40 CFR 180.1162 - Acrylate polymers and copolymers; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Acrylate polymers and copolymers... RESIDUES IN FOOD Exemptions From Tolerances § 180.1162 Acrylate polymers and copolymers; exemption from the requirement of a tolerance. (a) Acrylate polymers and copolymers are exempt from the requirement of a...

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... ferrite with acrylic ester polymer (generic). 721.10223 Section 721.10223 Protection of Environment... manganese ferrite with acrylic ester polymer (generic). (a) Chemical substance and significant new uses... manganese ferrite with acrylic ester polymer (PMN P-09-582) is subject to reporting under this section for...

40 CFR 180.1162 - Acrylate polymers and copolymers; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Acrylate polymers and copolymers... RESIDUES IN FOOD Exemptions From Tolerances § 180.1162 Acrylate polymers and copolymers; exemption from the requirement of a tolerance. (a) Acrylate polymers and copolymers are exempt from the requirement of a...

40 CFR 721.463 - Acrylate of polymer based on isophorone diisocyanate (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Acrylate of polymer based on... New Uses for Specific Chemical Substances § 721.463 Acrylate of polymer based on isophorone... substance identified generically as acrylate of polymer based on isophorone diisocyanate (PMN P-00-0626) is...

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... ferrite with acrylic ester polymer (generic). 721.10223 Section 721.10223 Protection of Environment... manganese ferrite with acrylic ester polymer (generic). (a) Chemical substance and significant new uses... manganese ferrite with acrylic ester polymer (PMN P-09-582) is subject to reporting under this section for...

40 CFR 721.463 - Acrylate of polymer based on isophorone diisocyanate (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acrylate of polymer based on... New Uses for Specific Chemical Substances § 721.463 Acrylate of polymer based on isophorone... substance identified generically as acrylate of polymer based on isophorone diisocyanate (PMN P-00-0626) is...

40 CFR 721.463 - Acrylate of polymer based on isophorone diisocyanate (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acrylate of polymer based on... New Uses for Specific Chemical Substances § 721.463 Acrylate of polymer based on isophorone... substance identified generically as acrylate of polymer based on isophorone diisocyanate (PMN P-00-0626) is...

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... ferrite with acrylic ester polymer (generic). 721.10223 Section 721.10223 Protection of Environment... manganese ferrite with acrylic ester polymer (generic). (a) Chemical substance and significant new uses... manganese ferrite with acrylic ester polymer (PMN P-09-582) is subject to reporting under this section for...

40 CFR 721.463 - Acrylate of polymer based on isophorone diisocyanate (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Acrylate of polymer based on... New Uses for Specific Chemical Substances § 721.463 Acrylate of polymer based on isophorone... substance identified generically as acrylate of polymer based on isophorone diisocyanate (PMN P-00-0626) is...

40 CFR 180.1162 - Acrylate polymers and copolymers; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Acrylate polymers and copolymers... RESIDUES IN FOOD Exemptions From Tolerances § 180.1162 Acrylate polymers and copolymers; exemption from the requirement of a tolerance. (a) Acrylate polymers and copolymers are exempt from the requirement of a...

40 CFR 180.1162 - Acrylate polymers and copolymers; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Acrylate polymers and copolymers... RESIDUES IN FOOD Exemptions From Tolerances § 180.1162 Acrylate polymers and copolymers; exemption from the requirement of a tolerance. (a) Acrylate polymers and copolymers are exempt from the requirement of a...

40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... ferrite with acrylic ester polymer (generic). 721.10223 Section 721.10223 Protection of Environment... manganese ferrite with acrylic ester polymer (generic). (a) Chemical substance and significant new uses... manganese ferrite with acrylic ester polymer (PMN P-09-582) is subject to reporting under this section for...

Nail Care Products

MedlinePlus

... Acrylics") Artificial nails are composed primarily of acrylic polymers and are made by reacting together acrylic monomers, such as ethyl methacrylate monomer, with acrylic polymers, such as polymethylmethacrylate. When the reaction is completed, ...

21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl acrylate...

21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl acrylate...

21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

Code of Federal Regulations, 2012 CFR

2012-04-01

... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl acrylate...

21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

Code of Federal Regulations, 2013 CFR

2013-04-01

... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl acrylate...

40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Butyl acrylate, polymer with... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6920 Butyl... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane...

21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

Code of Federal Regulations, 2014 CFR

2014-04-01

... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic.../methyl methacrylate polymers. The vinylidene chloride/methyl acrylate/methyl methacrylate polymers (CAS...

Microstructural aspects in steel fiber reinforced acrylic emulsion polymer modified concrete

NASA Astrophysics Data System (ADS)

Hazimmah, Dayang; Ayob, Afizah; Sie Yee, Lau; Chee Cung, Wong

2018-03-01

Scanning electron microscope observations of polymer-free and polymer-modified cements have shown that the polymer particles are partitioned between the inside of hydrates and the surface of anhydrous cement grains. For optimum dosage of acrylic emulsion polymer with 2.5%, the C-S-H gel in this structure is finer and more acicular. Some polymer adheres or deposit on the surface of the C-S-H gel. The presence of acrylic emulsion polymer confines the ionic diffusion so that the Ca(OH)2 crystallized locally to form fine crystals. The void in the structures seems to be smaller but no polymer films appears to be bridging the walls of pores although many polymer bonds or C-S-H spread into the pore spaces. In addition to porosity reduction, acrylic emulsion polymer modified the hydration products in the steel fiber -matrix ITZ. The hydration product C-S-H appeared as a needle like shape. The needle-shaped C-S-H increases and gradually formed the gel, with needles growing into the pore space. The phenomenon is more obvious as curing age increased.

Long-Life Self-Renewing Solar Reflector Stack

DOEpatents

Butler, Barry Lynn

1997-07-08

A long-life solar reflector includes a solar collector substrate and a base layer bonded to a solar collector substrate. The first layer includes a first reflective layer and a first acrylic or transparent polymer layer covering the first reflective layer to prevent exposure of the first reflective layer. The reflector also includes at least one upper layer removably bonded to the first acrylic or transparent polymer layer of the base layer. The upper layer includes a second reflective layer and a second acrylic or transparent polymer layer covering the second reflective layer to prevent exposure of the second reflective layer. The upper layer may be removed from the base reflective layer to expose the base layer, thereby lengthening the useful life of the solar reflector. A method of manufacturing a solar reflector includes the steps of bonding a base layer to a solar collector substrate, wherein the base reflective layer includes a first reflective layer and a first transparent polymer or acrylic layer covering the first reflective layer; and removably bonding a first upper layer to the first transparent polymer or acrylic layer of the base layer. The first upper layer includes a second reflective layer and a second transparent polymer or acrylic layer covering the second reflective layer to prevent exposure of the second reflective layer.

Additive manufacturing of short and mixed fibre-reinforced polymer

DOEpatents

Lewicki, James; Duoss, Eric B.; Rodriguez, Jennifer Nicole; Worsley, Marcus A.; King, Michael J.

2018-01-09

Additive manufacturing of a fiber-reinforced polymer (FRP) product using an additive manufacturing print head; a reservoir in the additive manufacturing print head; short carbon fibers in the reservoir, wherein the short carbon fibers are randomly aligned in the reservoir; an acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin in the reservoir, wherein the short carbon fibers are dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; a tapered nozzle in the additive manufacturing print head operatively connected to the reservoir, the tapered nozzle produces an extruded material that forms the fiber-reinforced polymer product; baffles in the tapered nozzle that receive the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; and a system for driving the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin from the reservoir through the tapered nozzle wherein the randomly aligned short carbon fibers in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin are aligned by the baffles and wherein the extruded material has the short carbon fibers aligned in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin that forms the fiber-reinforced polymer product.

Computational study of chain transfer to monomer reactions in high-temperature polymerization of alkyl acrylates.

PubMed

Moghadam, Nazanin; Liu, Shi; Srinivasan, Sriraj; Grady, Michael C; Soroush, Masoud; Rappe, Andrew M

2013-03-28

This article presents a computational study of chain transfer to monomer (CTM) reactions in self-initiated high-temperature homopolymerization of alkyl acrylates (methyl, ethyl, and n-butyl acrylate). Several mechanisms of CTM are studied. The effects of the length of live polymer chains and the type of monoradical that initiated the live polymer chains on the energy barriers and rate constants of the involved reaction steps are investigated theoretically. All calculations are carried out using density functional theory. Three types of hybrid functionals (B3LYP, X3LYP, and M06-2X) and four basis sets (6-31G(d), 6-31G(d,p), 6-311G(d), and 6-311G(d,p)) are applied to predict the molecular geometries of the reactants, products and transition sates, and energy barriers. Transition state theory is used to estimate rate constants. The results indicate that abstraction of a hydrogen atom (by live polymer chains) from the methyl group in methyl acrylate, the methylene group in ethyl acrylate, and methylene groups in n-butyl acrylate are the most likely mechanisms of CTM. Also, the rate constants of CTM reactions calculated using M06-2X are in good agreement with those estimated from polymer sample measurements using macroscopic mechanistic models. The rate constant values do not change significantly with the length of live polymer chains. Abstraction of a hydrogen atom by a tertiary radical has a higher energy barrier than abstraction by a secondary radical, which agrees with experimental findings. The calculated and experimental NMR spectra of dead polymer chains produced by CTM reactions are comparable. This theoretical/computational study reveals that CTM occurs most likely via hydrogen abstraction by live polymer chains from the methyl group of methyl acrylate and methylene group(s) of ethyl (n-butyl) acrylate.

Novel (meth)acrylate monomers for ultrarapid polymerization and enhanced polymer properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beckel, E. R.; Berchtold, K. A.; Nie, J.

2002-01-01

Ultraviolet light is known to be one of the most efficient methods to initiatc polymeric reactions in the presence of a photonitiator. Photopolymerizations are advantageous because the chemistry of the materials can be tailored to design liquid monomers for ultrarapid polymerization into a solid polymer material. One way to achieve rapid photopolymerizations is to utilize multifunctional (meth)acrylate monomers. which form highly crosslinked polymers; however, these monomers typically do not achieve complete functional group conversion. Recently, Decker et al. developed novel monovinyl acrylate monomers that display polyriicrization kinetics that rival those of multifunctional acrylate monomers. These novel acrylate monomers incorporate secondarymore » functionalities and end groups such as carbonates, carbamates, cyclic carbonates and oxazolidone which promote the increased polymerization kinetics of these monomers. In addition to thc polynierization kinetics, these novel monovinyl monomers form crosslinked polymers, which are characterized by having high strength and high flexibility. Unfortunately, the exact mechanism or mechanisms responsible for the polymerization kinetics and crosslinking are not well understood.« less

Synthesis of acrylic polymer beads for solid-supported proline-derived organocatalysts.

PubMed

Kristensen, Tor E; Vestli, Kristian; Fredriksen, Kim A; Hansen, Finn K; Hansen, Tore

2009-07-16

A completely non-chromatographic and highly large-scale adaptable synthesis of acrylic polymer beads containing proline and prolineamides has been developed. Novel monomeric proline (meth)acrylates are prepared from hydroxyproline in only one step. Free-radical copolymerization then gives solid-supported proline organocatalysts directly in as little as two steps overall, without using any prefabricated solid supports, by using either droplet or dispersion polymerization. These affordable acrylic beads have highly favorable and adjustable swelling characteristics and are excellent reusable catalysts for organocatalytic reactions.

Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC).

PubMed

Ritter, Helmut; Tabatabai, Monir; Herrmann, Markus

2016-01-01

We describe the synthesis of bromo-tert-butyloxycarbonyl (Br-t-BOC)-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t-BOC)-aminoethyl (meth)acrylate) 6a,b bearing protected amino side groups. The subsequent solvolysis of the Br-t-BOC function led to the new polymers poly(2-aminoethyl (meth)acrylate) 8a,b with protonated free amino groups. The monomers and the resulting polymers were thoroughly characterized by (1)H NMR, IR, GPC and DSC methods. The kinetics of the deprotection step was followed by (1)H NMR spectroscopy. The solvent polarity and neighboring group effects on the kinetics of deprotection are discussed.

Diffusion-Controlled Recrystallization of Water Sorbed into Poly(meth)acrylates Revealed by Variable-Temperature Mid-Infrared Spectroscopy and Molecular Dynamics Simulation.

PubMed

Yasoshima, Nobuhiro; Fukuoka, Mizuki; Kitano, Hiromi; Kagaya, Shigehiro; Ishiyama, Tatsuya; Gemmei-Ide, Makoto

2017-05-18

Recrystallization behaviors of water sorbed into four poly(meth)acrylates, poly(2-methoxyethyl acrylate), poly(tetrahydrofurfuryl acrylate), poly(methyl acrylate), and poly(methyl methacrylate), are investigated by variable-temperature mid-infrared (VT-MIR) spectroscopy and molecular dynamics (MD) simulation. VT-MIR spectra demonstrate that recrystallization temperatures of water sorbed into the polymers are positively correlated with their glass-transition temperatures reported previously. The present MD simulation shows that a lower-limit temperature of the diffusion for the sorbed water and the glass-transition temperatures of the polymers also have a positive correlation, indicating that the recrystallization is controlled by diffusion mechanism rather than reorientation mechanism. Detailed molecular processes of not only recrystallization during rewarming but also crystallization during cooling and hydrogen-bonding states of water in the polymers are systematically analyzed and discussed.

Thiol-vinyl systems as shape memory polymers and novel two-stage reactive polymer systems

NASA Astrophysics Data System (ADS)

Nair, Devatha P.

2011-12-01

The focus of this research was to formulate, characterize and tailor the reaction methodologies and material properties of thiol-vinyl systems to develop novel polymer platforms for a range of engineering applications. Thiol-ene photopolymers were demonstrated to exhibit several advantageous characteristics for shape memory polymer systems for a range of biomedical applications. The thiol-ene shape memory polymer systems were tough and flexible as compared to the acrylic control systems with glass transition temperatures between 30 and 40 °C; ideal for actuation at body temperature. The thiol-ene polymers also exhibited excellent shape fixity and a rapid and distinct shape memory actuation response along with free strain recoveries of greater than 96% and constrained stress recoveries of 100%. Additionally, two-stage reactive thiol-acrylate systems were engineered as a polymer platform technology enabling two independent sets of polymer processing and material properties. There are distinct advantages to designing polymer systems that afford two distinct sets of material properties -- an intermediate polymer that would enable optimum handling and processing of the material (stage 1), while maintaining the ability to tune in different, final properties that enable the optimal functioning of the polymeric material (stage 2). To demonstrate the range of applicability of the two-stage reactive systems, three specific applications were demonstrated; shape memory polymers, lithographic impression materials, and optical materials. The thiol-acrylate reactions exhibit a wide range of application versatility due to the range of available thiol and acrylate monomers as well as reaction mechanisms such as Michael Addition reactions and free radical polymerizations. By designing a series of non-stoichiometeric thiol-acrylate systems, a polymer network is initially formed via a base catalyzed 'click' Michael addition reaction. This self-limiting reaction results in a Stage 1 polymer with excess acrylic functional groups within the network. At a later point in time, the photoinitiated, free radical polymerization of the excess acrylic functional groups results in a highly crosslinked, robust material system. By varying the monomers within the system as well as the stoichiometery of thiol to acrylate functional groups, the ability of the two-stage reactive systems to encompass a wide range of properties at the end of both the stage 1 and stage 2 polymerizations was demonstrated. The thiol-acrylate networks exhibited intermediate Stage 1 rubbery moduli and glass transition temperatures that range from 0.5 MPa and -10 ºC to 22 MPa and 22 ºC respectively. The same polymer networks can then attain glass transition temperatures that range from 5 ºC to 195 ºC and rubbery moduli of up to 200 MPa after the subsequent photocure stage. Two-stage reactive polymer composite systems were also formulated and characterized for thermomechanical and mechanical properties. Thermomechanical analysis showed that the fillers resulted in a significant increase in the modulus at both stage 1 and stage 2 polymerizations without a significant change in the glass transition temperatures (Tg). The two-stage reactive matrix composite formed with a hexafunctional acrylate matrix and 20 volume % silica particles showed a 125% increase in stage 1 modulus and 101% increase in stage 2 modulus, when compared with the modulus of the neat matrix. Finally, the two-stage reactive polymeric devices were formulated and designed as orthopedic suture anchors for arthroscopic surgeries and mechanically characterized. The Stage 1 device was designed to exhibit properties ideal for arthroscopic delivery and device placement with glass transition temperatures 25 -- 30 °C and rubbery moduli ˜ 95 MPa. The subsequent photopolymerization generated Stage 2 polymers designed to match the local bone environment with moduli ranging up to 2 GPa. Additionally, pull-out strengths of 140 N were demonstrated and are equivalent to the pull-strengths achieved by other commercially available suture anchors.

40 CFR 180.1162 - Acrylate polymers and copolymers; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., and beads, as long as the fibers, beads and resins particle sizes are greater than 10 microns and insoluble in water. This exemption pertains to the acrylate polymers/copolymers used as inert ingredients...

The effect of extended polymer chains on the properties of transparent multi-walled carbon nanotubes/poly(methyl methacrylate/acrylic acid) film

NASA Astrophysics Data System (ADS)

Huang, Yuan-Li; Tien, Hsi-Wen; Ma, Chen-Chi M.; Yu, Yi-Hsiuan; Yang, Shin-Yi; Wei, Ming-Hsiung; Wu, Sheng-Yen

2010-05-01

Optically transparent and electrically conductive thin films composed of multi-walled carbon nanotube (MWCNT) reinforced polymethyl methacrylate/acrylic acid (PMMA/AA) were fabricated using a wire coating technique. Poly(acrylic acid) controls the level of MWCNT dispersion in aqueous mixtures and retains the well-dispersed state in the polymer matrix after solidification resulting from extended polymer chains by adjusting the pH value. The exfoliating the MWCNT bundles by extended polymer chains results in the excellent dispersion of MWCNT. It causes a lower surface electrical resistance at the same MWCNT content. The hydrophilic functional groups (-COO - NA + ) also caused a decrease in the crystallization of PMMA and led to an increase in the transmittance.

The effect of extended polymer chains on the properties of transparent multi-walled carbon nanotubes/poly(methyl methacrylate/acrylic acid) film.

PubMed

Huang, Yuan-Li; Tien, Hsi-Wen; Ma, Chen-Chi M; Yu, Yi-Hsiuan; Yang, Shin-Yi; Wei, Ming-Hsiung; Wu, Sheng-Yen

2010-05-07

Optically transparent and electrically conductive thin films composed of multi-walled carbon nanotube (MWCNT) reinforced polymethyl methacrylate/acrylic acid (PMMA/AA) were fabricated using a wire coating technique. Poly(acrylic acid) controls the level of MWCNT dispersion in aqueous mixtures and retains the well-dispersed state in the polymer matrix after solidification resulting from extended polymer chains by adjusting the pH value. The exfoliating the MWCNT bundles by extended polymer chains results in the excellent dispersion of MWCNT. It causes a lower surface electrical resistance at the same MWCNT content. The hydrophilic functional groups (-COO( - )NA( + )) also caused a decrease in the crystallization of PMMA and led to an increase in the transmittance.

Poly(meth)acrylate-based coatings.

PubMed

Nollenberger, Kathrin; Albers, Jessica

2013-12-05

Poly(meth)acrylate coatings for pharmaceutical applications were introduced in 1955 with the launch of EUDRAGIT(®) L and EUDRAGIT(®) S, two types of anionic polymers. Since then, by introducing various monomers into their polymer chains and thus altering their properties, diverse forms with specific characteristics have become available. Today, poly(meth)acrylates function in different parts of the gastrointestinal tract and/or release the drug in a time-controlled manner. This article reviews the properties of various poly(meth)acrylates and discusses formulation issues as well as application possibilities. Copyright © 2013 Elsevier B.V. All rights reserved.

Magnetic particles

NASA Technical Reports Server (NTRS)

Chang, Manchium (Inventor); Colvin, Michael S. (Inventor); Rembaum, Alan (Inventor); Richards, Gil F. (Inventor)

1987-01-01

Metal oxide containing polymers and particularly styrene, acrylic or protein polymers containing fine, magnetic iron oxide particles are formed by combining a NO.sub.2 -substituted polymer with an acid such as hydrochloric acid in the presence of metal, particularly iron particles. The iron is oxidized to fine, black Fe.sub.3 O.sub.4 particles which deposit selectively on the polymer particles. Nitrated polymers are formed by reacting functionally substituted, nitrated organic compounds such as trinitrobenzene sulfonate or dinitrofluoro benzene with a functionally coreactive polymer such as an amine modified acrylic polymer or a protein. Other transition metals such as cobalt can also be incorporated into polymers using this method.

Repair and Rehabilitation of Dams: Case Studies

DTIC Science & Technology

1999-09-01

with fiber - reinforced , acrylic- polymer modi- fied concrete (FRAPMC) and eliminating leakage into the trunnion recesses. FRAPMC consists of mortar...coarse aggregate, and reinforcement fibers . It is mixed in a mortar mixer as a two-component system consisting of a liquid polymer emulsion of...seat was removed and replaced with fiber - reinforced , acrylic- polymer modified concrete (FRAPMC). New bridge seats were installed, allowing for more

21 CFR 173.5 - Acrylate-acrylamide resins.

Code of Federal Regulations, 2010 CFR

2010-04-01

... and acrylic acid, with the greater part of the polymer being composed of acrylamide units. (2) Sodium polyacrylate-acrylamide resin is produced by the polymerization and subsequent hydrolysis of acrylonitrile in a sodium silicate-sodium hydroxide aqueous solution, with the greater part of the polymer being composed of...

21 CFR 173.5 - Acrylate-acrylamide resins.

Code of Federal Regulations, 2011 CFR

2011-04-01

... and acrylic acid, with the greater part of the polymer being composed of acrylamide units. (2) Sodium polyacrylate-acrylamide resin is produced by the polymerization and subsequent hydrolysis of acrylonitrile in a sodium silicate-sodium hydroxide aqueous solution, with the greater part of the polymer being composed of...

Water evaporation on highly viscoelastic polymer surfaces.

PubMed

Pu, Gang; Severtson, Steven J

2012-07-03

Results are reported for a study on the evaporation of water droplets from a highly viscoelastic acrylic polymer surface. These are contrasted with those collected for the same measurements carried out on polydimethylsiloxane (PDMS). For PDMS, the evaporation process involves the expected multistep process including constant drop area, constant contact angle, and finally a combination of these steps until the liquid is gone. In contrast, water evaporation from the acrylic polymer shows a constant drop area mode throughout. Furthermore, during the evaporation process, the drop area actually expands on the acrylic polymer. The single mode evaporation process is consistent with formation of wetting structures, which cannot be propagated by the capillary forces. Expansion of the drop area is attributed to the influence of the drop capillary pressure. Furthermore, the rate of drop area expansion is shown to be dependent on the thickness of the polymer film.

Design and Fabrication of NxN Optical Couplers Based on Organic Polymer Opti al WaveGuides

DTIC Science & Technology

1994-08-01

lOxlO optical coupler utilizing photopolymerizable organic polymers. Background information on the theory of operation of the coupler culminating in a...Channel Waveguides Based on Photopolymerizable Di/Tri Acrylates," in Optoelecwonic Interconnects Ii, Ray T. Chen, John A. Neff, Editors, Proc. SPIE 2153, pp...demonstrated that acrylic polymers can be used to fabricate single-mode optical wavguides. The resins that we have formulated are photopolymerizable

Industrially relevant epoxy-acrylate hybrid resin photopolymerizations

NASA Astrophysics Data System (ADS)

Ajiboye, Gbenga I.

Photopolymerization of epoxy-acrylate hybrid resins takes advantages of inherent properties present in the free-radical and cationic reactions to reduce oxygen inhibition problems that plague free-radical reactions. Similarly, the combined reaction mechanisms reduce moisture sensitivity of the cationic reactions. Despite the advantages of epoxy-acrylate hybrid resins, problems persist that need to be addressed. For example, low conversion and polymerization rate of the epoxides are a problem, because the fast acrylate conversion prevents the epoxide from reaching high conversion. Controlling phase separation is challenging, since two moieties with different properties are reacting. The physical properties of the polymer will be impacted by the availability of different moieties. High shrinkage stress results from the acrylate moiety, causing buckling and cracking in film and coating applications. The overall goal of this study is to use the fundamental knowledge of epoxy-acrylate hybrid resins to formulate industrially viable polymers. In order to achieve this goal, the study focuses on the following objectives: (I) determine the apparent activation energy of the hybrid monomer METHB, (II) increase epoxide conversion and polymerization rate of hybrid formulations, and (III) control physical properties in epoxy-acrylate hybrid resins. In order to increase the epoxide conversion and rate of polymerization, the sensitivity of epoxides to alcohol is used to facilitate the activated monomer (AM) mechanism and induce a covalent bond between the epoxide and acrylate polymers through the hydroxyl group. It is hypothesized that if the AM mechanism is facilitated, epoxide conversion will increase. As a result, the resins can be tailored to control phase separation and physical properties, and shrinkage stress can be reduced. In pursuit of these objectives, the hybrid monomer METHB was polymerized at temperatures ranging from 30°C to 70°C to obtain apparent activation energy of 23.49 kJ/mol for acrylate and 57 kJ/mol for epoxide moeities. Then, hybrid systems pairing hydroxyl-containing acrylates with epoxides were formulated to promote the faster AM mechanism. Monomer composition was changed in the presence of hydroxyl-containing acrylate, and initiators were carefully selected in order to control phase separation. The conversion of acrylate and epoxide was monitored in real time by Raman spectroscopy. The physical and mechanical properties were monitored using dynamic mechanical analysis. Epoxide conversion and rate of polymerization in epoxide-acrylate hybrid monomer systems were shown to increase through the introduction of a hydroxyl group on the meth/acrylate monomer, taking advantage of the faster AM mechanism. In addition, this covalent bond linking the epoxide network to the meth/acrylate polymer chains resulted in little or no phase separation and a reduction of the Tg for the hybrid polymer compared to the neat epoxide. Fundamental knowledge gained from this research will enable the use of epoxy-acrylate hybrid resins in variety of applications. For instance, shrinkage may be reduced in dental fillings, noise and vibration problems in aircraft and other machinery may be controlled, and photopolymerization cost could be reduced in thin film applications.

Porous and non-porous water soluble polymer nanospheres

NASA Astrophysics Data System (ADS)

Henselwood, Fred William

Water soluble polymer nanospheres have been prepared from the photo-cross-linking of diblock copolymer micelles formed either in water or in N,N-dimethylformamide/water mixtures. The diblock copolymers utilized in this study were poly(2-cinnamoyl-ethyl methacrylate)-block-poly(acrylic acid), poly ((2-cinnamoylethyl methacrylate)-random-(2-octanoylethyl methacrylate)) -block-poly(acrylic acid), and poly ((2-cinnamoyl-ethyl methacrylate)-random-(2-oleoylethyl methacrylate)) -block-poly(acrylic acid). These polymers were synthesized by the functionalization of diblock copolymers prepared by anionic polymerization. The photo-cross-linking was achieved through the dimerization of cinnamoyl groups by ultraviolet irradiation. Transmission electron microscopy confirmed that the polymer nanospheres had an inner core region formed by the cinnamoyl containing polymer blocks, and an outer shell layer formed by the acrylic acid polymer blocks. The hydrodynamic radius of the polymer nanospheres in water was approximately 50 to 75 nm as determined by dynamic light scattering. It has been found that the polymer nanospheres, when in water, could be readily impregnated with organic molecules. Fluorescence measurements showed that the polymer nanospheres could uptake polyaromatic hydrocarbons by the direct mixing of polyaromatic hydrocarbons with the polymer nanospheres in water. Perylene was found to be between 2.0 × 10sp5 and 4.0 × 10sp5 times more soluble in the core region of the polymer nanospheres than in water. The addition of divalent cations was shown to induce aggregation of the polymer nanospheres and resulted in the precipitation of the polymer nanospheres along with any captured perylene. This suggests that the polymer nanospheres may be useful in water remediation. Porous polymer nanospheres were prepared by the incorporation of low molecular weight polymeric porogens within the core region of the polymer nanospheres. Following photo-cross-linking the polymeric porogens were extracted out of the polymer nanospheres resulting in pore formation. Perylene loading experiments revealed that the loading of the porous polymer nanospheres was 41% higher than that achieved for non-porous polymer nanospheres prepared from the same initial diblock copolymer. This indicates that the porous polymer nanospheres may be preferred over the non-porous polymer nanospheres in applications such as drug delivery.

Microcontact printing for patterning carbon nanotube/polymer composite films with electrical conductivity.

PubMed

Ogihara, Hitoshi; Kibayashi, Hiro; Saji, Tetsuo

2012-09-26

Patterned carbon nanotube (CNT)/acrylic resin composite films were prepared using microcontact printing (μCP). To prepare ink for μCP, CNTs were dispersed into propylene glycol monomethyl ether acetate (PGMEA) solution in which acrylic resin and a commercially available dispersant (Disperbyk-2001) dissolved. The resulting ink were spin-coated onto poly(dimethylsiloxane) (PDMS) stamps. By drying solvent components from the ink, CNT/polymer composite films were prepared over PDMS stamps. Contact between the stamps and glass substrates provided CNT/polymer composite patternings on the substrates. The transfer behavior of the CNT/polymer composite films depended on the thermal-treatment temperature during μCP; thermal treatment at temperatures near the glass-transition temperature (T(g)) of the acrylic resin was effective to form uniform patternings on substrates. Moreover, contact area between polymer and substrates also affect the transfer behavior. The CNT/polymer composite films showed high electrical conductivity, despite the nonconductivity of polymer components, because CNTs in the films were interconnected. The electrical conductivity of the composite films increased as CNT content in the film became higher; as a result, the composite patternings showed almost as high electrical conductivity as previously reported CNT/polymer bulk composites.

Waterborne Polymeric Films.

DTIC Science & Technology

1979-12-01

resin types: 1) acrylic latex, 2) acrylic solution polymer, 3) epoxy emulsions, 4) polyurethane, 5) butadiene elastomeric latex, 6) polyester/ alkyd , 7...emulsions and the class of polyester/ alkyd resins were evaluated only as network, crosslinked films. -53- j z I, ACRYLIC SOLUTIONLATEX URE THANE ACRYLIC ...amount of "plasticizing" monomer such as ethyl acrylate . 2.3.1.3 Aqueous Polyester Alkyd Resins As indicated in section 2.2.7 of this report,

Thiolated polymers: evaluation of their potential as dermoadhesive excipients.

PubMed

Grießinger, Julia Anita; Bonengel, Sonja; Partenhauser, Alexandra; Ijaz, Muhammad; Bernkop-Schnürch, Andreas

2017-02-01

The objective of this study was to evaluate and compare four different thiolated polymers regarding their dermoadhesive potential. Therefore, three hydrophilic polymers (poly(acrylic acid), Carbopol 971 and carboxymethylcellulose) and a lipophilic polymer (silicone oil) were chosen to generate thiolated polymers followed by characterization. The total work of adhesion (TWA) and the maximum detachment force (MDF) of formulations containing modified and unmodified polymers were investigated on skin obtained from pig ears using a tensile sandwich technique. The synthesis of thiolated polymers provided 564 µmol, 1079 µmol, 482 µmol and 217 µmol thiol groups per gram poly(acrylic acid), Carbopol 971, carboxymethylcellulose and silicone oil, respectively. Hydrogels containing poly(acrylic acid)-cysteine, Carbopol 971-cysteine, and carboxymethylcellulose-cysteamine exhibited a 6-fold, 25-fold and 9-fold prolonged adhesion on porcine skin than the hydrogel formulations prepared from the corresponding unmodified polymers, respectively. Furthermore, thiolation of silicone oil with thioglycolic acid led to a 5-fold improvement in adhesion compared to the unmodified silicone oil. A comparison between the four thiolated polymer formulations showed a clear correlation between the amount of coupled thiol groups and the TWA. According to these results thiomers might also be useful excipients to provide a prolonged dermal resistance time of various formulations.

Polyacrylates with High Biomass Contents for Pressure-Sensitive Adhesives Prepared via Mini-emulsion Polymerization

Treesearch

Gang Pu; Matthew R. Dubay; Jiguang Zhang; Steven J. Severtson; Carl J. Houtman

2012-01-01

n-Butyl acrylate and other acrylic monomers were copolymerized with an acrylated macromonomer to produce polymers for pressure-sensitive adhesive (PSA) applications. Macromonomers were generated through the ring-opening copolymerization of L-lactide and ε-caprolactone with 2-hydroxyethyl...

Effect of a Polymercaptan Material on the Electro-Optical Properties of Polymer-Dispersed Liquid Crystal Films.

PubMed

Sun, Yujian; Zhang, Cuihong; Zhou, Le; Fang, Hua; Huang, Jianhua; Ma, Haipeng; Zhang, Yi; Yang, Jie; Zhang, Lan-Ying; Song, Ping; Gao, Yanzi; Xiao, Jiumei; Li, Fasheng; Li, Kexuan

2016-12-30

Polymer-dispersed liquid crystal (PDLC) films were prepared by the ultraviolet-light-induced polymerization of photopolymerizable monomers in nematic liquid crystal/chiral dopant/thiol-acrylate reaction monomer composites. The effects of the chiral dopant and crosslinking agents on the electro-optical properties of the PDLC films were systematically investigate. While added the chiral dopant S811 into the PDLC films, the initial off-state transmittance of the films was decreased. It was found that the weight ratio among acrylate monomers, thiol monomer PETMP and the polymercaptan Capcure 3-800 showed great influence on the properties of the fabricated PDLC films because of the existence of competition between thiol-acrylate reaction and acrylate monomer polymerization reaction. While adding polymercaptans curing agent Capcure 3-800 with appropriate concentration into the PDLC system, lower driven voltage and higher contrast ratio were achieved. This made the polymer network and electro-optical properties of the PDLC films easily tunable by the introduction of the thiol monomers.

Folic acid conjugated cross-linked acrylic polymer (FA-CLAP) hydrogel for site specific delivery of hydrophobic drugs to cancer cells.

PubMed

Pillai, Jisha Jayadevan; Thulasidasan, Arun Kumar Theralikattu; Anto, Ruby John; Chithralekha, Devika Nandan; Narayanan, Ashwanikumar; Kumar, Gopalakrishnapillai Sankaramangalam Vinod

2014-07-15

The hydrogel based system is found to be rarely reported for the delivery of hydrophobic drug due to the incompatibility of hydrophilicity of the polymer network and the hydrophobicity of drug. This problem can be solved by preparing semi-interpenetrating network of cross-linked polymer for tuning the hydrophilicity so as to entrap the hydrophobic drugs. The current study is to develop a folic acid conjugated cross-linked pH sensitive, biocompatible polymeric hydrogel to achieve a site specific drug delivery. For that, we have synthesized a folic acid conjugated PEG cross-linked acrylic polymer (FA-CLAP) hydrogel and investigated its loading and release of curcumin. The formed polymer hydrogel was then conjugated with folic acid for the site specific delivery of curcumin to cancer cells and then further characterized and conducted the cell uptake and cytotoxicity studies on human cervical cancer cell lines (HeLa). In this study, we synthesized folic acid conjugated cross-linked acrylic hydrogel for the delivery of hydrophobic drugs to the cancer site. Poly (ethyleneglycol) (PEG) diacrylate cross-linked acrylic polymer (PAA) was prepared via inverse emulsion polymerization technique and later conjugated it with folic acid (FA-CLAP). Hydrophobic drug curcumin is entrapped into it and investigated the entrapment efficiency. Characterization of synthesized hydogel was done by using Fourier Transform-Infrared spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC). Polymerization and folate conjugation was confirmed by FT-IR spectroscopy. The release kinetics of drug from the entrapped form was studied which showed initial burst release followed by sustained release due to swelling and increased cross-linking. In vitro cytotoxicity and cell uptake studies were conducted in human cervical cancer (HeLa) cell lines. Results showed that curcumin entrapped folate conjugated cross-linked acrylic polymer (FA-CLAP) hydrogel showed higher cellular uptake than the non folate conjugated form. So this can be suggested as a better delivery system for site specific release of hydrophobic cancer drugs.

Development of materials from copolyacrylates via atom transfer radical polymerization

NASA Astrophysics Data System (ADS)

Jones, Melody Mersadez

Homopolymerization of 2-(trimethylsilyl)ethyl acrylate, 3,3-dimethylbutyl acrylate, methyl acrylate, and methyl methacrylate using atom transfer radical polymerization (ATRP) is reported. In addition, polymethyl acrylate and polymethyl methacrylate were used as macroinitiators for diblock copolymerizations (via ATRP) with various monomers to yield pMA-b-TMSEA, pMMA-b-TMSEA, and pMMA-b-GMA copolymers; these results are also reported. Controlled polymerizations were performed using the CuBr/hexamethyltriethylenetetramine catalyst system in combination with methyl bromopropionate as the initiator. The protected acid block copolymers pMA-b-TMSEA and pMMA-b-TMSEA were deprotected to afford acrylic and meth acrylic acid block copolymers pMA-b-AA and pMMA-b-AA. Methylene chloride was used to micellize the amphiphilic copolymers in order to obtain the critical micelle concentration of the polymers (CMCpMA-b-AA = 10 mg/mL, CMCpMMA-b-AA = 0.4 mg/mL). The majority of polymerization were done in bulk; however, since poly(trimethylsilyl)ethyl acrylate displayed polydispersity (Mn = 11459, PDI = 1.437) on the high end of the acceptable range, various solvents were utilized to decrease the polymerization rate and afford low polydispersity materials. This differs from the ATRP of polymethyl acrylate or polymethyl methacrylate using this catalytic system, which do not require the addition of a solvent to obtain well-defined polymers. Also, for this polymerization system three different temperatures (60°C, 90°C, and 120°C) were used, in order to reduce the concentration of radicals and the contribution of termination. The homopolymers and protected acid block copolymers were characterized by gel permeation chromatography to determine the relative molecular weights. Differential scanning calorimetry was used to obtain the glass transition temperature of all polymers. Characterization using NMR (1H and 13C) and FTIR confirmed homopolymerization of 3,3-dimethylbutyl acrylate, 2-(trimethylsilyl)ethyl acrylate and complete cleavage of the (trimethylsilyl)ethyl group from the protected acid copolymers.

Two Players Make a Formidable Combination: In Situ Generated Poly(acrylic anhydride-2-methyl-acrylic acid-2-oxirane-ethyl ester-methyl methacrylate) Cross-Linking Gel Polymer Electrolyte toward 5 V High-Voltage Batteries.

PubMed

Ma, Yue; Ma, Jun; Chai, Jingchao; Liu, Zhihong; Ding, Guoliang; Xu, Gaojie; Liu, Haisheng; Chen, Bingbing; Zhou, Xinhong; Cui, Guanglei; Chen, Liquan

2017-11-29

Electrochemical performance of high-voltage lithium batteries with high energy density is limited because of the electrolyte instability and the electrode/electrolyte interfacial reactivity. Hence, a cross-linking polymer network of poly(acrylic anhydride-2-methyl-acrylic acid-2-oxirane-ethyl ester-methyl methacrylate) (PAMM)-based electrolyte was introduced via in situ polymerization inspired by "shuangjian hebi", which is a statement in a traditional Chinese Kungfu story similar to the synergetic effect of 1 + 1 > 2. A poly(acrylic anhydride) and poly(methyl methacrylate)-based system is very promising as electrolyte materials for lithium-ion batteries, in which the anhydride and acrylate groups can provide high voltage resistance and fast ionic conductivity, respectively. As a result, the cross-linking PAMM-based electrolyte possesses a significant comprehensive enhancement, including electrochemical stability window exceeding 5 V vs Li + /Li, an ionic conductivity of 6.79 × 10 -4 S cm -1 at room temperature, high mechanical strength (27.5 MPa), good flame resistance, and excellent interface compatibility with Li metal. It is also demonstrated that this gel polymer electrolyte suppresses the negative effect resulting from dissolution of Mn 2+ ions at 25 and 55 °C. Thus, the LiNi 0.5 Mn 1.5 O 4 /Li and LiNi 0.5 Mn 1.5 O 4 /Li 4 Ti 5 O 12 cells using the optimized in situ polymerized cross-linking PAMM-based gel polymer electrolyte deliver stable charging/discharging profiles and excellent rate performance at room temperature and even at 55 °C. These findings suggest that the cross-linking PAMM is an intriguing candidate for 5 V class high-voltage gel polymer electrolyte toward high-energy lithium-on batteries.

Development and characterization of amorphous acrylate networks for use as switchable adhesives inspired from shapememory behavior

NASA Astrophysics Data System (ADS)

Lakhera, Nishant

Several types of insects and animals such as spiders and geckos are inherently able to climb along vertical walls and ceilings. This remarkable switchable adhesive behavior has been attributed to the fibrillar structures on their feet, with size ranging from few nanometers to a few micrometers depending on the species. Several studies have attempted to create synthetic micro-patterned surfaces trying to imitate this adhesive behavior seen in nature. The experimental procedures are scattered, with sole purpose of trying to increase adhesion, thereby making direct comparison between studies very difficult. There is a lack of fundamental understanding on adhesion of patterned surfaces. The influence of critical parameters like material modulus, glass transition temperature, viscoelastic effects, temperature and water absorption on adhesion is not fully explored and characterized. These parameters are expected to have a decisive influence on adhesion behavior of the polymer. Previous studies have utilized conventional "off-the-shelf" materials like epoxy, polyurethanes etc. It is however, impossible to change the material modulus, glass transition temperature etc. of these polymer systems without changing the base constituents itself, thereby explaining the gaps in the current research landscape. The purpose of this study was to use acrylate shape-memory polymers (SMPs) for their ability to be tailored to specific mechanical properties by control of polymer chemistry, without changing the base constituents. Polymer networks with tailorable glass transition, material modulus, water absorption etc. were developed and adhesion studies were performed to investigate the influence of temperature, viscoelastic effects, material modulus on the adhesion behavior of flat acrylate polymer surfaces. The knowledge base gained from these studies was utilized to better understand the fundamental mechanisms associated with adhesion behavior of patterned acrylate surfaces. Thermally induced switchable adhesion and water induced switchable adhesion of patterned acrylate surfaces was investigated. The viscoelastic energy dissipation occurring during the detachment phase was shown to dramatically increase adhesion under both thermally induced and water induced conditions. This effect was most pre-dominant at the glass transition temperature of the material. Increase in pre-load force and unloading velocity were also shown to increase the adhesive capability of the patterned acrylate SMPs.

Synthesis and properties of a novel bio-based polymer from modified soybean oil

NASA Astrophysics Data System (ADS)

Li, Y. T.; Yang, L. T.; Zhang, H.; Tang, Z. J.

2017-02-01

Maleated acrylated epoxidized soybean oil (MAESO) was prepared by acrylated epoxidized soybean oil (AESO) and maleic anhydride. AESO were obtained by the reaction of epoxidized soybean oil (ESO) with acrylic acid as the ring-opening reagent. The polymer was prepared by MAESO react with styrene. The structures of the products were studied by Fourier transformation infrared spectrometer (FT-IR), and were consistent with the theoretical structures. Swelling experiment indicated that the crosslinking degree increased with increasing epoxy value of ESO. Thermal properties was tested by thermo-gravimetric analysis (TG) and differential scanning calorimetry analysis (DSC), indicating that glass transition temperature (Tg) of the polymer increased with increasing epoxy value of ESO, and thermal stability of polymer have a good correlation with the crosslinking degree. Mechanical properties analysis presented that tensile strength and impact strength affected by epoxy value of ESO. With the increase of epoxy value, the tensile strength increase, while the impact strength decrease. The property of the polymer ranged from elastomer to plastic character depended on the functionality of the ESO.

Bioinspired bioadhesive polymers: dopa-modified poly(acrylic acid) derivatives.

PubMed

Laulicht, Bryan; Mancini, Alexis; Geman, Nathanael; Cho, Daniel; Estrellas, Kenneth; Furtado, Stacia; Hopson, Russell; Tripathi, Anubhav; Mathiowitz, Edith

2012-11-01

The one-step synthesis and characterization of novel bioinspired bioadhesive polymers that contain Dopa, implicated in the extremely adhesive byssal fibers of certain gastropods, is reported. The novel polymers consist of combinations of either of two polyanhydride backbones and one of three amino acids, phenylalanine, tyrosine, or Dopa, grafted as side chains. Dopa-grafted hydrophobic backbone polymers exhibit as much as 2.5 × the fracture strength and 2.8 × the tensile work of bioadhesion of a commercially available poly(acrylic acid) derivative as tested on live, excised, rat intestinal tissue. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gas response behaviour and photochemistry of borondiketonate in acrylic polymer matrices for sensing applications.

PubMed

Arias Espinoza, Juan Diego; Sazhnikov, Viacheslav; Smits, Edsger C P; Ionov, Dmirity; Kononevich, Yuriy; Yakimets, Iryna; Alfimov, Mikael; Schoo, Herman F M

2014-11-01

The fluorescent spectra in combination with gas response behavior of acrylic polymers doped with dibenzoyl(methanato)boron difluoride (DBMBF2) were studied by fluorescence spectroscopy and time-resolved fluorescence lifetime. The role of acrylic matrix polarity upon the fluorescence spectra and fluorescence lifetime was analyzed. Changes in emission of the dye doped polymers under exposure to toluene, n-hexane and ethanol were monitored. The fluorescence lifetimes were measured for the singlet excited state as well as the exciplex formed between DBMBF2 and toluene. A reduction of the transition energy to the first singlet-excited state in the four polymers was observed, compared to solution. Reversible exciplex formation, viz. a red shifted fluorescence emission was perceived when exposing the polymers to toluene, while for hexane and ethanol only reversible reduction of the fluorescence occurred. Longer singlet and shorter exciplex lifetimes were observed for non-polar matrixes. The latter mechanism is explained in function of the lower charge transfer character of the exciplex in non-polar matrixes. Additionally, the quantum yield of the dye in the polymer matrix increased almost seventh-fold compared to values for solution.

Thermodynamic Interactions between Polystyrene and Long-Chain Poly(n-Alkyl Acrylates) Derived from Plant Oils.

PubMed

Wang, Shu; Robertson, Megan L

2015-06-10

Vegetable oils and their fatty acids are promising sources for the derivation of polymers. Long-chain poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) are readily derived from fatty acids through conversion of the carboxylic acid end-group to an acrylate or methacrylate group. The resulting polymers contain long alkyl side-chains with around 10-22 carbon atoms. Regardless of the monomer source, the presence of alkyl side-chains in poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) provides a convenient mechanism for tuning their physical properties. The development of structured multicomponent materials, including block copolymers and blends, containing poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) requires knowledge of the thermodynamic interactions governing their self-assembly, typically described by the Flory-Huggins interaction parameter χ. We have investigated the χ parameter between polystyrene and long-chain poly(n-alkyl acrylate) homopolymers and copolymers: specifically we have included poly(stearyl acrylate), poly(lauryl acrylate), and their random copolymers. Lauryl and stearyl acrylate were chosen as model alkyl acrylates derived from vegetable oils and have alkyl side-chain lengths of 12 and 18 carbon atoms, respectively. Polystyrene is included in this study as a model petroleum-sourced polymer, which has wide applicability in commercially relevant multicomponent polymeric materials. Two independent methods were employed to measure the χ parameter: cloud point measurements on binary blends and characterization of the order-disorder transition of triblock copolymers, which were in relatively good agreement with one another. The χ parameter was found to be independent of the alkyl side-chain length (n) for large values of n (i.e., n > 10). This behavior is in stark contrast to the n-dependence of the χ parameter predicted from solubility parameter theory. Our study complements prior work investigating the interactions between polystyrene and short-chain polyacrylates (n ≤ 10). To our knowledge, this is the first study to explore the thermodynamic interactions between polystyrene and long-chain poly(n-alkyl acrylates) with n > 10. This work lays the groundwork for the development of multicomponent structured systems (i.e., blends and copolymers) in this class of sustainable materials.

Acrylic and metal based Y-branch plastic optical fiber splitter with optical NOA63 polymer waveguide taper region

NASA Astrophysics Data System (ADS)

Ehsan, Abang Annuar; Shaari, Sahbudin; Rahman, Mohd Kamil Abd.

2011-01-01

We proposed a simple low-cost acrylic and metal-based Y-branch plastic optical fiber (POF) splitter which utilizes a low cost optical polymer glue NOA63 as the main waveguiding medium at the waveguide taper region. The device is composed of three sections: an input POF waveguide, a middle waveguide taper region and output POF waveguides. A desktop high speed CNC engraver is utilized to produce the mold inserts used for the optical devices. Short POF fibers are inserted into the engraved slots at the input and output ports. UV curable optical polymer glue NOA63 is injected into the waveguide taper region and cured. The assembling is completed when the top plate is positioned to enclose the device structure and connecting screws are secured. Both POF splitters have an average insertion loss of 7.8 dB, coupling ratio of 55: 45 and 57: 43 for the acrylic and metal-based splitters respectively. The devices have excess loss of 4.82 and 4.73 dB for the acrylic and metal-based splitters respectively.

Nonlinear Optical Acrylic Polymers and Use Thereof in Optical and Electro-Optic Devices

DTIC Science & Technology

1992-01-07

COVERED 4. TITLE AND SUBTITLE Nonlinear Optical Acrylic Polymers and Use Thereof in Optical and Electro - Optic Devices 5a. CONTRACT NUMBER 5b. GRANT...generators, computational devices and the like. 15. SUBJECT TERMS optical devices, electro - optical devices, optical signal processing...THEREOF IN OPTICAL AND ELECTRO - OPTIC DEVICES [75] Inventors: Le*lie H. Sperling, Bethlehem; Clarence J. Murphy, Stroudsburg; Warren A. Rosen

Synthetic consolidants attacked by melanin-producing fungi: case study of the biodeterioration of Milan (Italy) cathedral marble treated with acrylics.

PubMed

Cappitelli, Francesca; Nosanchuk, Joshua D; Casadevall, Arturo; Toniolo, Lucia; Brusetti, Lorenzo; Florio, Sofia; Principi, Pamela; Borin, Sara; Sorlini, Claudia

2007-01-01

Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks.

Coatings and Biodegradable and Bioasorbable Films

DTIC Science & Technology

2006-12-28

linseed oil and soy oil VOMMs were designed and synthesized including linseed acrylate monomer (LiAM), soy acrylate monomer (SAM), soy amide acrylate...the plasticizing effects of vegetable oil macromonomers as incorporated into emulsion polymers for efficient almost zero VOC film formation and the...Environmentally friendly coatings, Topside Navy Haze Gray, Vegetable Oil Macromonomer, Low VOC, Biodegradable Food Packaging, Polyester-Polyurethanes

Effect of Antiadherents on the Physical and Drug Release Properties of Acrylic Polymeric Films.

PubMed

Ammar, Hussein O; Ghorab, Mamdouh M; Felton, Linda A; Gad, Shadeed; Fouly, Aya A

2016-06-01

Antiadherents are used to decrease tackiness of a polymer coating during both processing and subsequent storage. Despite being a common excipient in coating formulae, antiadherents may affect mechanical properties of the coating film as well as drug release from film-coated tablets, but how could addition of antiadherents affect these properties and to what extent and is there a relation between the physical characteristics of the tablet coat and the drug release mechanisms? The aim of this study was to evaluate physical characteristics of films containing different amounts of the antiadherents talc, glyceryl monostearate, and PlasACRYL(TM) T20. Eudragit RL30D and Eudragit RS30D as sustained release polymers and Eudragit FS30D as a delayed release material were used. Polymer films were characterized by tensile testing, differential scanning calorimetry (DSC), microscopic examination, and water content as calculated from loss on drying. The effect of antiadherents on in vitro drug release for the model acetylsalicylic acid tablets coated with Eudragit FS30D was also determined. Increasing talc concentration was found to decrease the ability of the polymer films to resist mechanical stress. In contrast, glyceryl monostearate (GMS) and PlasACRYL produced more elastic films. Talc at concentrations higher than 25% caused negative effects, which make 25% concentration recommended to be used with acrylic polymers. All antiadherents delayed the drug release at all coating levels; hence, different tailoring of drug release may be achieved by adjusting antiadherent concentration with coating level.

Preparation, Characterization and Utilization of Electrodes Coated with Polymeric Networks Formed by Gamma Radiation Crosslinking.

DTIC Science & Technology

1987-04-01

polymers such as poly[ diallyl dimethyl ammonium chloride] , poly [vinylbenzyl trimethyl ammonium chloride], poly[styrene sulfonic acid , sodium salt] and...poly[acrylic acid ], which would ordinarily dissolve from the electrode surface in aqueous solution unless crosslinked into a network, and several...Irradiation on a Water-Soluble Polymer: DDAC 8 E. Electrochemistry of DDAC Networks on Platinum and Graphite 10 F. Poly [acrylic acid ] Films on Graphite

Synthesis and characterization of UV-absorbing fluorine-silicone acrylic resin polymer

NASA Astrophysics Data System (ADS)

Lei, Huibin; He, Deliang; Guo, Yanni; Tang, Yining; Huang, Houqiang

2018-06-01

A series of UV-absorbing fluorine-silicone acrylic resin polymers containing different amount of UV-absorbent were successfully prepared by solution polymerization, with 2-[3-(2H-Benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate (BHEM), vinyltrimethoxysilane (VTMS) and hexafluorobutyl methacrylate (HFMA) as modifying monomers. The acrylic polymers and the coatings thereof were characterized by Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible (UV-vis) absorption spectrum, thermogravimetric analysis (TGA), water contact angle (CA) and Xenon lamp artificial accelerated aging tests. Results indicated that the resin exhibited high UV absorption performance as well as good thermal stability. The hydrophobicity of the coatings was of great improvement because of the bonded fluorine and silicone. Meanwhile, the weather-resistance was promoted through preferably colligating the protective effects of BHEM, organic fluorine and silicone. Also, a fitting formula about the weatherability with the BMHE content was tentatively proposed.

Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography.

PubMed

Zhang, Shu-Xin; Chai, Xin-Sheng; Jiang, Ran

2017-02-17

This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20min at 70°C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD<2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control. Copyright © 2017 Elsevier B.V. All rights reserved.

Constitutive Analyses of Nontraditional Stabilization Additives

DTIC Science & Technology

2004-11-01

cm-I Figure 29. FTIRIATR spectrum of Ven-Set 950 soil stabilization agent Based on the information provided in the MSDS and the FTIR analysis above...emulsion. The MSDS states that it is composed of an acrylic polymer (52 percent) with zinc oxide (2 percent), activated carbon (8 to 9 percent), and...water. The polymer as yet is unidentified. However, it appears to be an acrylate/ methacrylate with some aromaticity (peak about 1,635 c-f’). The

Michael Addition Polymerization of Trifunctional Amine and Acrylic Monomer: A Versatile Platform for Development of Biomaterials.

PubMed

Cheng, Weiren; Wu, Decheng; Liu, Ye

2016-10-10

Michael addition polymerizations of amines and acrylic monomers are versatile approaches to biomaterials for various applications. A combinatorial library of poly(β-amino ester)s and diverse poly(amido amine)s from diamines and diacrylates or bis(acrylamide)s have been reported, respectively. Furthermore, novel linear and hyperbranched polymers from Michael addition polymerizations of trifunctional amines and acrylic monomers significantly enrich this category of biomaterials. In this Review, we focus on the biomaterials from Michael addition polymerizations of trifunctional amines and acrylic monomers. First we discuss how the polymerization mechanisms, which are determined by the reactivity sequence of the three types of amines of trifunctional amines, i.e., secondary (2°) amines (original), primary (1°) amines, and 2° amines (formed), are affected by the chemistry of monomers, reaction temperature, and solvent. Then we update how to design and synthesize linear and hyperbranched polymers based on the understanding of polymerization mechanisms. Linear polymers containing 2° amines in the backbones can be obtained from polymerizations of diacrylates or bis(acrylamide)s with equimolar trifunctional amine, and several approaches, e.g., 2A 2 +BB'B″, A 3 +2BB'B', A 2 +BB'B″, to hyperbranched polymers are developed. Further through molecular design of monomers, conjugation of functional species to 2° amines in the backbones of linear polymers and the abundant terminal groups of hyperbranched polymers, the amphiphilicity of polymers can be adjusted, and additional stimuli, e.g., thermal, redox, reactive oxidation species (ROS), and light, responses can be integrated with the intrinsic pH response. Finally we discuss the applications of the polymers for gene/drug delivery and bioimaging through exploring their self-assemblies in various motifs, e.g., micelles, polyplexes particles/nanorings and hydrogels. Redox-responsive hyperbranched polymers can display 300 times higher in vitro gene transfection efficiency and provide a higher in vivo siRNA efficacy than PEI. Also redox-responsive micelle carriers can improve the efficacy of anticancer drug and the bioimaging contrast. Further molecular design and optimization of this category of polymers together with in vivo studies should provide safe and efficient biomaterials for clinical applications.

Polymer brush covalently attached to OH-functionalized mica surface via surface-initiated ATRP: control of grafting density and polymer chain length.

PubMed

Lego, Béatrice; François, Marion; Skene, W G; Giasson, Suzanne

2009-05-05

The controlled grafting density of poly(tert-butyl acrylate) was studied on OH-activated mica substrates via surface-initiated atom-transfer radical polymerization (ATRP). By properly adjusting parameters such as the immobilization reaction time and the concentration of an ATRP initiator, a wide range of initiator surface coverages and hence polymer densities on mica were possible. The covalently immobilized initiator successfully promoted the polymerization of tert-butyl acrylate on mica surfaces. The resulting polymer layer thickness was measured by AFM using a step-height method. Linear relationships of the polymer thickness with respect to the molecular weight of the free polymer and with respect to the monomer conversion were observed, suggesting that ATRP is well controlled and relatively densely end-grafted layers were obtained. The polymer grafting density controlled by adjusting the initiator surface coverage was confirmed by the polymer layer swelling capacity and film thickness measurements.

21 CFR 175.365 - Vinylidene chloride copolymer coatings for polycarbonate film.

Code of Federal Regulations, 2014 CFR

2014-04-01

... conditions: (a) The coating is applied as a continuous film over one or both sides of a base film produced... acrylate, and acrylic acid. The finished copolymers contain at least 50 weight-percent of polymer units...

PROPERTY ANALYSIS OF TRIGLYCERIDE-BASED THERMOSETS. (R829576)

EPA Science Inventory

Triglycerides with acrylate functionality were prepared from various oils and
model triglycerides. The triglyceride-acrylates were homopolymerized and copolymerized
with styrene. The cross-link densities of the resulting polymer networks were
predicted utilizing the F...

Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites

NASA Technical Reports Server (NTRS)

Liaw, Benjamin; Zeichner, Glenn; Liu, Yanxiong; Bowles, Kenneth J. (Technical Monitor)

2000-01-01

The main objective of this NASA FAR project is to conduct ultrasonic assessment of impact-induced damage and microcracking in polymer matrix composites at various temperatures. It is believed that the proposed study of impact damage assessment on polymer matrix composites will benefit several NASA's missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Currently, impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.

Gel polymer electrolytes based on nanofibrous polyacrylonitrile–acrylate for lithium batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Dul-Sun; Woo, Jang Chang; Youk, Ji Ho, E-mail: youk@inha.ac.kr

2014-10-15

Graphical abstract: - Highlights: • Nanofibrous polyacrylonitrile–acrylate membranes were prepared by electrospinning. • Trimethylolpropane triacrylate was used as a crosslinking agent of fibers. • The GPE based on PAN–acrylate (1/0.5) showed good electrochemical properties. - Abstract: Nanofibrous membranes for gel polymer electrolytes (GPEs) were prepared by electrospinning a mixture of polyacrylonitrile (PAN) and trimethylolpropane triacrylate (TMPTA) at weight ratios of 1/0.5 and 1/1. TMPTA is used to achieve crosslinking of fibers thereby improving mechanical strength. The average fiber diameters increased with increasing TMPTA concentration and the mechanical strength was also improved due to the enhanced crosslinking of fibers. GPEs basedmore » on electrospun membranes were prepared by soaking them in a liquid electrolyte of 1 M LiPF{sub 6} in ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1, v/v). The electrolyte uptake and ionic conductivity of GPEs based on PAN and PAN–acrylate (weight ratio; 1/1 and 1/0.5) were investigated. Ionic conductivity of GPEs based on PAN–acrylate was the highest for PAN/acrylate (1/0.5) due to the proper swelling of fibers and good affinity with liquid electrolyte. Both GPEs based on PAN and PAN–acrylate membranes show good oxidation stability, >5.0 V vs. Li/Li{sup +}. Cells with GPEs based on PAN–acrylate (1/0.5) showed remarkable cycle performance with high initial discharge capacity and low capacity fading.« less

Facile Fabrication of Gradient Surface Based on (meth)acrylate Copolymer Films

NASA Astrophysics Data System (ADS)

Zhang, Y.; Yang, H.; Wen, X.-F.; Cheng, J.; Xiong, J.

2016-08-01

This paper describes a simple and economic approach for fabrication of surface wettability gradient on poly(butyl acrylate - methyl methacrylate) [P (BA-MMA)] and poly(butyl acrylate - methyl methacrylate - 2-hydroxyethyl methacrylate) [P (BA-MMA-HEMA)] films. The (meth)acrylate copolymer [including P (BA-MMA) and P (BA-MMA-HEMA)] films are hydrolyzed in an aqueous solution of NaOH and the transformation of surface chemical composition is achieved by hydrolysis in NaOH solution. The gradient wetting properties are generated based on different functional groups on the P (BA-MMA) and P (BA-MMA-HEMA) films. The effects of both the surface chemical and surface topography on wetting of the (meth)acrylate copolymer film are discussed. Surface chemical composition along the materials length is determined by XPS, and surface topography properties of the obtained gradient surfaces are analyzed by FESEM and AFM. Water contact angle system (WCAs) results show that the P (BA-MMA-HEMA) films provide a larger slope of the gradient wetting than P (BA-MMA). Moreover, this work demonstrates that the gradient concentration of chemical composition on the poly(meth) acrylate films is owing to the hydrolysis processes of ester group, and the hydrolysis reactions that have negligible influence on the surface morphology of the poly(meth) acrylate films coated on the glass slide. The gradient wettability surfaces may find broad applications in the field of polymer coating due to the compatibility of (meth) acrylate polymer.

Solid phase graft copolymerization of acrylic monomers onto thermoplastics and their use as blend compatibilizers

NASA Astrophysics Data System (ADS)

Subramanian, Srinivas

This research work is an extension of some of the earlier work done on the development of solid phase grafting technique to graft various monomers onto polymers as well as postulation of the usefulness of the graft copolymers thus synthesized. Polystyrene grafted with acrylic acid, previously developed in bench scale, was synthesized in pilot-plant scale batches. Process parameter studies on the grafting of acrylic acid onto polypropylene and developmental studies on the grafting of maleic anhydride onto polystyrene were also done. Polymers grafted with polar molecules such as maleic anhydride and acrylic acid have been used to compatibilize immiscible blends of polar and non-polar polymers. On the same note, the applicability of the solid phase graft copolymers as blend compatibilizers were investigated and their performance was compared to commercially available compatibilizers. Solid phase graft copolymerization process is a technique to synthesize graft copolymers. Some of its salient features are use of minimal solvent to conduct the reaction and easy equipment modification. It is a low pressure and low temperature process. This technique provides a viable alternative to the environmentally hazardous, and time consuming conventional process currently in use. Hence, development of this technique could be beneficial not only to the plastics industry, but also to mankind. Also, this technique provides a low-cost and extremely easy method to develop graft copolymers such as acrylic acid functionalized polymers that are rapidly gaining popularity as blend compatibilizers and polymer reinforcing agents. A study that proves the potential of these solid phase graft copolymers as good blend compatibilizers for industrially important immiscible polymers will develop interest in the industries about this grafting process. The free radical solid phase graft copolymerization process was carried in a modified Brabender-type mixer fitted with specially designed blades to promote efficient mixing of the polymer, initiator, monomer, and solvent. The grafting was qualitatively confirmed by means of a FTIR and quantitatively using titration. The polymer blends were synthesized in a single screw extruder. Rheological, morphological, thermal, mechanical, and molecular weight studies were done on these blends. The graft copolymers produced in larger batches had the same amount of graft content as those produced in smaller batches. This small success is a positive step towards the goal of commercializing this process. Grafting of acrylic acid onto polypropylene gave graft levels of 4 weight percent. However, the attempt to graft maleic anhydride onto polystyrene was not successful. The solid phase graft copolymers were successfully able to compatibilize the polymer blend systems studied (PS/PMMA, PS/nylon 6,6, PS/nylon 6, and PP/nylon 6). The properties of the blends compatibilized using the solid phase graft copolymers were comparable to and in some instances, better than those of the blends compatibilized with commercially available graft copolymers. The successful scale-up of the process, development of new graft copolymers and ability of copolymers to compatibilize blends augurs well for the solid phase grafting process.

Hierarchically organized architecture of potassium hydrogen phthalate and poly(acrylic acid): toward a general strategy for biomimetic crystal design.

PubMed

Oaki, Yuya; Imai, Hiroaki

2005-12-28

A hierarchically organized architecture in multiple scales was generated from potassium hydrogen phthalate crystals and poly(acrylic acid) based on our novel biomimetic approach with an exquisite association of polymers on crystallization.

Effect of fluorinated groups on photooxidative stability of polymeric protectives applied on marble.

PubMed

Chiantore, O; Poli, T; Colombo, C; Peruzzi, R; Toniolo, L

2001-01-01

Some new protective copolymers and a commercial one have been tested on Candoglia marble, a very low porosity stone. Two of the polymers contained a partially fluorinated methacrylic monomer, 2,2,2 trifluoro ethyl methacrylate (TFEMA), in combination with either an acrylic, methyl acrylate (MA) or a vinyl ether, n-butyl vinyl ether (n-BVE) unit. Two copolymers, ethyl methacrylate/n-butyl vinyl ether and ethyl methacrylate (EMA)/methyl acrylate (Paraloid B72), were non-fluorinated and similar in compositions and molar ratio. The aim of the work is to test the copolymers and compare the performances of fluorinated new polymers with the non fluorinated one and with the largely used commercial product. The results obtained demonstrate that the introduction, even in limited amounts, of fluorine atoms in the side ester groups of methacrylic type polymers really improves their protective effect and the durability of the stone treatments. The best results were obtained with the copolymer TFEM/MA which is the fluorinated homologous of Paraloid B72.

Antifungal Effect of Henna against Candida albicans Adhered to Acrylic Resin as a Possible Method for Prevention of Denture Stomatitis

PubMed Central

Nawasrah, Amal; AlNimr, Amani; Ali, Aiman A.

2016-01-01

Denture stomatitis is a very common disease affecting the oral mucosa of denture wearers. The aim of this study was to measure the antifungal effect of henna against Candida albicans adhered to acrylic resin as a possible method for prevention of denture stomatitis. One-hundred-eighty acrylic plates were prepared of heat-cured acrylic denture resin. The specimens were divided into six groups of 30 samples each. The first group was only polymer and monomer following the conventional manufacturer instruction for processing complete dentures. The other five groups were processed by adding different concentration of Yamani henna powder (Harazi) to the polymer in a concentration of henna: polymer 1%, 2.5%, 5%, 7.5% and 10%, respectively. Samples were incubated in artificial saliva rich with Candida albicans at 37 °C, and the effect of henna on Candida albicans was evaluated in two different methods: semi-quantitative slide count and a culture-based quantitative assay (quantitative). Variation in the number of live Candida was observed with the increase in the concentration of Yamani henna powder. It was observed that the variation in live Candida, between control group and group B (concentration of Yamani henna powder was 1%), was statistically significant with a p-value of 0.0001. Similarly, variations in live Candida were significant, when the concentration of powder was 7.5% or 10% in contrast with control group and p-values were 0.0001 and 0.001 respectively. Adding henna to acrylic resin denture could be effective in controlling Candida albicans proliferation on the denture surface; however, its effects on the physical properties of acrylic resin denture need further studies. PMID:27223294

Synthesis and characterization of POSS-(PAA)8 star copolymers and GICs for dental applications.

PubMed

Zelmer, Christina; Wang, David K; Keen, Imelda; Hill, David J T; Symons, Anne L; Walsh, Laurence J; Rasoul, Firas

2016-04-01

To investigate the application of a new type of multiarm polymer resins in the formulation of Glass Ionic Cements. A series of star copolymers of t-butyl acrylate has been prepared by ATRP using a multiarm POSS-Br8 initiator. The resulting POSS-co-t-butyl acrylate star copolymers with eight arms were subsequently hydrolysed by trifluoroacetic acid to produce the corresponding POSS-co-acrylic acid star copolymers. All of the copolymers have been characterized by (1)H and (13)C NMR and FTIR spectroscopies and TGA/DSC. The as-prepared star copolymers were mixed with the glass powder from Fuji IX GP to produce the GIC samples for compression testing. The new type of multiarm polymer resins have been shown to have narrow molecular weight distributions and thermal properties of the acrylic acid copolymers are similar to that of poly(acrylic acid), with a two stage degradation profile involving transitions at ≈140°C and 250°C, corresponding to anhydride formation and loss of carbon dioxide, respectively. In aqueous solution the POSS-co-acrylic acid copolymers form aggregates with ≈33nm dimensions. When aqueous solutions of POSS-(PAA)8 are mixed with a glass powder, a rigid glass ionomer cement, GIC, is formed with a maximum compressive stress significantly greater than that for a linear PAA GIC of a comparable polymer molecular weight. Therefore, these POSS-(PAA)8 copolymers demonstrate the potential for the application of well characterized star copolymers in the future development of new GICs as dental materials. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Matrix normalized MALDI-TOF quantification of a fluorotelomer-based acrylate polymer.

PubMed

Rankin, Keegan; Mabury, Scott A

2015-05-19

The degradation of fluorotelomer-based acrylate polymers (FTACPs) has been hypothesized to serve as a source of the environmental contaminants, perfluoroalkyl carboxylates (PFCAs). Studies have relied on indirect measurement of presumed degradation products to evaluate the environmental fate of FTACPs; however, this approach leaves a degree of uncertainty. The present study describes the development of a quantitative matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry method as the first direct analysis method for FTACPs. The model FTACP used in this study was poly(8:2 FTAC-co-HDA), a copolymer of 8:2 fluorotelomer acrylate (8:2 FTAC) and hexadecyl acrylate (HDA). Instead of relying on an internal standard polymer, the intensities of 40 poly(8:2 FTAC-co-HDA) signals (911-4612 Da) were normalized to the signal intensity of a matrix-sodium cluster (659 Da). We termed this value the normalized polymer response (P(N)). By using the same dithranol solution for the sample preparation of poly(8:2 FTAC-co-HDA) standards, calibration curves with coefficient of determinations (R(2)) typically >0.98 were produced. When poly(8:2 FTAC-co-HDA) samples were prepared with the same dithranol solution as the poly(8:2 FTAC-co-HDA) standards, quantification to within 25% of the theoretical concentration was achieved. This approach minimized the sample-to-sample variability that typically plagues MALDI-TOF, and is the first method developed to directly quantify FTACPs.

Triggered metal ion release and oxidation: Ferrocene as new mechanophore in polymers.

PubMed

Di Giannantonio, Michela; Ayer, Mathieu A; Verde-Sesto, Ester; Lattuada, Marco; Weder, Christoph; Fromm, Katharina M

2018-06-13

The introduction of mechanophores into polymers allows transducing mechanical forces into chemical reactions for e.g. self-healing, catalytic activity, or mechanochromic response. Here, the first example of mechanically induced metal ion release from a polymer is reported. Ferrocene (Fc) was incorporated as an Fe-ion releasing mechanophore into poly(methyl acrylate)s (PMAs) and polyurethanes (PUs). Sonication triggered the preferential cleavage of the polymers at the Fc units over other bonds, as shown by a kinetic study of the molar mass distribution of the cleaved Fc-containing and Fc-free reference polymers. The released and oxidized Fe2+ ions can be detected with KSCN to generate the red-colored [Fe(SCN)n(H2O)6-n)](3-n)+ or reacted with K4[Fe(CN)6] to afford Prussian blue. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

21 CFR 175.210 - Acrylate ester copolymer coating.

Code of Federal Regulations, 2014 CFR

2014-04-01

... polymerized copolymer of ethyl acrylate, methyl methacrylate, and methacrylic acid applied in emulsion form to... of the polymer and in the preparation and application of the emulsion may include substances named in... amount required as a preservative in emulsion defoamer. Disodium hydrogen phosphate Do. Formaldehyde...

Synthetic Consolidants Attacked by Melanin-Producing Fungi: Case Study of the Biodeterioration of Milan (Italy) Cathedral Marble Treated with Acrylics▿

PubMed Central

Cappitelli, Francesca; Nosanchuk, Joshua D.; Casadevall, Arturo; Toniolo, Lucia; Brusetti, Lorenzo; Florio, Sofia; Principi, Pamela; Borin, Sara; Sorlini, Claudia

2007-01-01

Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks. PMID:17071788

ToF-SIMS analysis of a polymer microarray composed of poly(meth)acrylates with C6 derivative pendant groups.

PubMed

Hook, Andrew L; Scurr, David J

2016-04-01

Surface analysis plays a key role in understanding the function of materials, particularly in biological environments. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) provides highly surface sensitive chemical information that can readily be acquired over large areas and has, thus, become an important surface analysis tool. However, the information-rich nature of ToF-SIMS complicates the interpretation and comparison of spectra, particularly in cases where multicomponent samples are being assessed. In this study, a method is presented to assess the chemical variance across 16 poly(meth)acrylates. Materials are selected to contain C 6 pendant groups, and ten replicates of each are printed as a polymer microarray. SIMS spectra are acquired for each material with the most intense and unique ions assessed for each material to identify the predominant and distinctive fragmentation pathways within the materials studied. Differentiating acrylate/methacrylate pairs is readily achieved using secondary ions derived from both the polymer backbone and pendant groups. Principal component analysis (PCA) is performed on the SIMS spectra of the 16 polymers, whereby the resulting principal components are able to distinguish phenyl from benzyl groups, mono-functional from multi-functional monomers and acrylates from methacrylates. The principal components are applied to copolymer series to assess the predictive capabilities of the PCA. Beyond being able to predict the copolymer ratio, in some cases, the SIMS analysis is able to provide insight into the molecular sequence of a copolymer. The insight gained in this study will be beneficial for developing structure-function relationships based upon ToF-SIMS data of polymer libraries. © 2016 The Authors Surface and Interface Analysis Published by John Wiley & Sons Ltd.

A STUDY OF THE MECHANISM OF RADIATION-INDUCED GELATION IN MONOMER-POLYMER MIXTURES. Quarterly Summary Report, August 1, 1961-October 31, 1961

DOE Office of Scientific and Technical Information (OSTI.GOV)

Odian, G.; Bernstein, B.S.; Kelly, J.J.

1961-11-01

Gel contents can be obtained with polyethylene swollen with inhibitor- free allyl acrylate or inhibitor-free allyl methacrylate at a dose of only 0.05 Mrads Using Co/sup 60/ as the radiation source, allyl methacrylate gives higher gel content than allyl acrylate under similar conditions. icant and continues after Co/sup 60/ irradiation has been completed. Monomer desorption after a dose of 1.2 Mrads is less than after 0.05 Mrads, and does not continue after irradiation is stopped. Gel contents can be obtained without prior equilibrium swelling of polymer--monomer mixtures by irradiating the polymer in the presence of the monomer in a nitrogenmore » atmosphere. By irradiating under these conditions with prior equilibrium swelling, gel fractions appear to be higher than those normally obtained. Gel contents of irradiated equilibrium-swollen polyethylene/ allyl acrylate and polyethylene/allyl methacrylate increase with increasing radiation dose from 0.05 to 1.2 Mrads. Gel contents of 1.2 Mrad irradiated polyethyleneallyl methacrylate systems containing various initial amounts of monomer, increase with increasing monomer content. Polypropylene can be radiation crosslinked to give over 40% gel by prior equilibrium swelling with allyl acrylate or allyl methacrylate. (auth)« less

Development of new resist materials for 193-nm dry and immersion lithography

NASA Astrophysics Data System (ADS)

Sasaki, Takashi; Shirota, Naoko; Takebe, Yoko; Yokokoji, Osamu

2006-03-01

We earlier developed new monocyclic fluoropolymers (FUGU) for F II resist materials. But, it is necessary for FUGU to improve of their characteristics, especially the dry-etching resistance, in order to apply for ArF lithography at fine design rules. We have tried to combine FUGUs with Adamntyl methacrylates based conventional ArF resist polymer. In this paper, we have investigated the role of cyclic fluorinated unit, FUGU, in 193 nm resist polymers by analyzing the dissolution behavior. We found that FGEAM showed high sensitivity and good dissolution contrast, compared with acrylate based conventional samples at low PEB temperature (100 °C). And this difference of sensitivity was clearly found when weak acidity PAGs were used. From the dissolution behaviors of FGEAM, FUGU unit can work to improve the resist sensitivity in acrylate based ArF resist polymers. And we also found that FGEAM showed long acid diffusion length on PEB process, compared with Conventional samples. These result show that FUGU unit has a unique characteristics of the sensitivity with 193nm exposure and the acid diffusion behavior. We also investigated a new series of fluorinated copolymers for 193-nm lithography, combination of FUGU monomer and acrylate units which are used in conventional ArF resist. Six ter-polymers of FUGU, combination of FUGU monomers and EAdMA, GBLMA and HAdMA were prepared. We found that FUGU ter-polymers had a good dry etching resistance keeping high transparency at 193nm. And FUGU ter-polymers showed high sensitivity toward 193nm exposure. FUGU ter-polymers also had a high hydrophobic properties compared conventional type ArF resist polymers. So we also expect FUGU ter-polymers to be useful for ArF dry and immersion lithography.

Vacuum-deposited polymer/silver reflector material

NASA Astrophysics Data System (ADS)

Affinito, John D.; Martin, Peter M.; Gross, Mark E.; Bennett, Wendy D.

1994-09-01

Weatherable, low cost, front surface, solar reflectors on flexible substrates would be highly desirable for lamination to solar concentrator panels. The method to be described in this paper may permit such reflector material to be fabricated for less the 50$CNT per square foot. Vacuum deposited Polymer/Silver/Polymer reflectors and Fabry-Perot interference filters were fabricated in a vacuum web coating operation on polyester substrates. Reflectivities were measured in the wavelength range from .4 micrometers to .8 micrometers . It is hoped that a low cost substrate can be used with the substrate laminated to the concentrator and the weatherable acrylic polymer coating facing the sun. This technique should be capable of deposition line speeds approaching 1500 linear feet/minute2. Central to this technique is a new vacuum deposition process for the high rate deposition of polymer films. This polymer process involves the flash evaporation of an acrylic monomer onto a moving substrate. The monomer is subsequently cured by an electron beam or ultraviolet light. This high speed polymer film deposition process has been named the PML process- for Polymer Multi- Layer.

[The tissue reaction to acrylic plastics modified by supercritical extraction with carbon dioxide].

PubMed

Volozhin, A I; Shekhter, A B; Karakov, K G; Sukhanov, Iu P; Gavril'chak, A V; Popov, V K; Antonov, E N; Karrot, M

1998-01-01

The process of extraction of admixtures from acryl plastic widely used in dentistry by means of supercritical carbon dioxide (sc-CO2) was studied and effects of extraction conditions on biocompatibility and toxicity of resultant materials assessed, sc-CO2 effectively purified the specimens from toxic compounds (monomers and low-molecular oligomers, methylmethacrylate, dichloroethane) and notably improved the biocompatability of polymer implants. Tissue reaction to ethacryl and protacryl depends on the degree of implant polymerization and duration of extraction of toxic substances from polymer.

Bistable electroactive polymer for refreshable Braille display with improved actuation stability

NASA Astrophysics Data System (ADS)

Niu, Xiaofan; Brochu, Paul; Stoyanov, Hristiyan; Yun, Sung Ryul; Pei, Qibing

2012-04-01

Poly(t-butyl acrylate) is a bistable electroactive polymer (BSEP) capable of rigid-to-rigid actuation. The BSEP combines the large-strain actuation of dielectric elastomers with shape memory property. We have introduced a material approach to overcome pull-in instability in poly(t-butyl acrylate) that significantly improves the actuation lifetime at strains greater than 100%. Refreshable Braille display devices with size of a smartphone screen have been fabricated to manifest a potential application of the BSEP. We will report the testing results of the devices by a Braille user.

Polymer grafted magnetic nanoparticles for delivery of anticancer drug at lower pH and elevated temperature.

PubMed

Dutta, Sujan; Parida, Sheetal; Maiti, Chiranjit; Banerjee, Rakesh; Mandal, Mahitosh; Dhara, Dibakar

2016-04-01

Efficient and controlled delivery of therapeutics to tumor cells is one of the important issues in cancer therapy. In the present work, a series of pH- and temperature-responsive polymer grafted iron oxide nanoparticles were prepared by simple coupling of aminated iron oxide nanoparticle with poly(N-isopropylacrylamide-ran-poly(ethylene glycol) methyl ether acrylate)-block-poly(acrylic acid) (P(NIPA-r-PEGMEA)-b-PAA). For this, three water soluble block polymers were prepared via reversible addition fragmentation transfer (RAFT) polymerization technique. At first, three different block copolymers were prepared by polymerizing mixture of NIPA and PEGMEA (with varying mole ratio) in presence of poly(tert-butyl acrylate) (PtBA) macro chain transfer agent. Subsequently, P(NIPA-r-PEGMEA)-b-PAA copolymers were synthesized by hydrolyzing tert-butyl acrylate groups of the P(NIPA-r-PEGMEA)-b-PtBA copolymers. The resulting polymers were then grafted to iron oxide nanoparticles, and these functionalized nanoparticles were thoroughly characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), zeta potential measurements, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and Fourier transform infrared spectroscopy (FTIR). Doxorubicin (DOX), an anti-cancer drug, was loaded into the polymer coated nanoparticles and its release behavior was subsequently studied at different pH and temperatures. The drug release pattern revealed a sustained release of DOX preferentially at the desired lysosomal pH of cancer cells (pH 5.0) and slightly above the physiological temperature depending upon the composition of the copolymers. The potential anticancer activity of the polymer grafted DOX loaded nanoparticles were established by MTT assay and apoptosis study of cervical cancer ME 180cells in presence of the nanoparticles. Thus, these particles can be utilized for controlled delivery of anticancer drugs at the desired lysosomal pH and/or by slightly heating the cells using magnetic hyperthermia. Copyright © 2016 Elsevier Inc. All rights reserved.

Stabilized polyacrylic saccharide protein conjugates

DOEpatents

Callstrom, Matthew R.; Bednarski, Mark D.; Gruber, Patrick R.

1996-01-01

This invention is directed to water soluble protein polymer conjugates which are stabile in hostile environments. The conjugate comprises a protein which is linked to an acrylic polymer at multiple points through saccharide linker groups.

Monomers, polymers and articles containing the same from sugar derived compounds

DOEpatents

Gallagher, James; Reineke, Theresa; Hillmyer, Marc A.

2016-11-29

Disclosed herein are monomers formed by reacting a sugar derived compound(s) comprising a lactone and two hydroxyls with a compound(s) comprising an isocyanate and an acrylate or methacrylate. Polymers formed from such monomers, and articles formed from the polymers are also disclosed.

21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false n-Alkylglutarimide/acrylic copolymers. 177.1060 Section 177.1060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated...

21 CFR 177.1340 - Ethylene-methyl acrylate copolymer resins.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene-methyl acrylate copolymer resins. 177.1340 Section 177.1340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and...

Corrosion-Inhibiting Coating Composition.

DTIC Science & Technology

1990-03-01

acrylic polymers were designed for compatibility with the alkyd resins and are useful therefore in preparing coatings of improved hardness...Hydrocarbon solvents 10 to 50 Componentam PatIbyWih Acrylic resin (B-67) 17.3 Silicone resin (SR-80M) 17.3 Silicone- alkyd resin 8.6 (V(ARKYD 385-50E...aichol e.6 VM&P Naphtha 17.1 Example II I ComponentPatbyWgh Acrylic resin 17.3 15 Silicone resin 17.3 Silicone- alkyd resin 8.6 Alkyl

Fracture analysis of CAD-CAM high-density polymers used for interim implant-supported fixed, cantilevered prostheses.

PubMed

Yilmaz, Burak; Alp, Gülce; Seidt, Jeremy; Johnston, William M; Vitter, Roger; McGlumphy, Edwin A

2018-01-06

The load-to-fracture performance of computer-assisted design and computer-assisted manufacturing (CAD-CAM) high-density polymer (HDP) materials in cantilevers is unknown. The purposes of this in vitro study were to evaluate the load-to-fracture performance of CAD-CAM-fabricated HDPs and to compare that with performance of autopolymerized and injection-molded acrylic resins. Specimens from 8 different brands of CAD-CAM HDPs, including Brylic Solid (BS); Brylic Gradient (BG); AnaxCAD Temp EZ (AE); AnaxCAD Temp Plus (AP); Zirkonzahn Temp Basic (Z); GDS Tempo-CAD (GD); Polident (Po); Merz M-PM-Disc (MAT); an autopolymerized acrylic resin, Imident (Conv) and an injection-molded acrylic resin, SR-IvoBase High Impact (Inj) were evaluated for load-to-fracture analysis (n=5). CAD-CAM specimens were milled from poly(methyl methacrylate) (PMMA) blocks measuring 7 mm in buccolingual width, 8 mm in occlusocervical thickness, and 30 mm in length. A wax pattern was prepared in the same dimensions used for CAD-CAM specimens, flasked, and boiled out. Autopolymerizing acrylic resin was packed and polymerized in a pressure container for 30 minutes. An identical wax pattern was flasked and boiled out, and premeasured capsules were injected (SR-IvoBase) and polymerized under hydraulic pressure for 35 minutes for the injection-molded PMMA. Specimens were thermocycled 5000 times (5°C to 55°C) and fixed to a universal testing machine to receive static loads on the 10-mm cantilever, vertically at a 1 mm/min crosshead speed until fracture occurred. Maximum load-to-fracture values were recorded. ANOVA was used to analyze the maximum force values. Significant differences among materials were analyzed by using the Ryan-Einot-Gabriel-Welsch multiple range test (α=.05). Statistically significant differences were found among load-to-fracture values of different HDPs (P<.001). GD and Po materials had significantly higher load-to-fracture values than other materials (P<.001), and no statistically significant differences were found between GD and Po. The lowest load-to-fracture values were observed for autopolymerized and BG materials, which were significantly lower than those of GD, Po, AE, AP, Z, MAT, Inj, and BS. The load-to-fracture value of autopolymerized acrylic resin was not significantly different from that of BG CAD-CAM polymer. GD and Po CAD-CAM materials had the highest load-to-fracture values. AE, AP, Z, MAT, and BS CAD-CAM polymers and injection-molded acrylic resin had similar load-to-fracture values, which were higher than those of BG and autopolymerized acrylic resin. Autopolymerized acrylic resin load-to-fracture value was similar to that of BG CAD-CAM polymer, which is colored in a gradient pattern. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Ionizing radiation in the field of hydrogels used for agriculture and medicine

NASA Astrophysics Data System (ADS)

Radoiu, M.; Martin, D.; Oproiu, C.; Toma, M.; Popescu, A. S.; Bestea, V.; Dragusin, M.; Moraru, R.; Calinescu, I.; Manea, A.

1999-01-01

Some hydrogel types, obtained by gamma ray and electron beam irradiation, such as homopolymers of acrylamide (pAA type), co-polymers of acrylamide and sodium acrylate (pAANA type), homo-polymers of sodium acrylate (pNA type) and homo-polymers of 2-hydroxyethylmethacrylate (pHEMA type), are presented. The effects of the solution's chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of pAA, pAANA, pNA types are discussed. For the pHEMA type, which are reinforced in the polyester network, the studies concerning the influence of the irradiation parameters and chemical composition upon the shape stability after swelling and surface's roughness are also discussed.

Stabilized polyacrylic saccharide protein conjugates

DOEpatents

Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

1996-02-20

This invention is directed to water soluble protein polymer conjugates which are stable in hostile environments. The conjugate comprises a protein which is linked to an acrylic polymer at multiple points through saccharide linker groups. 16 figs.

Preparation of Fe 3O 4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride) by emulsifier-free emulsion polymerization and its interaction with DNA

NASA Astrophysics Data System (ADS)

Li, Xiaolong; Liu, Guoqiang; Yan, Wei; Chu, Paul K.; Yeung, Kelvin W. K.; Wu, Shuilin; Yi, Changfeng; Xu, Zushun

2012-04-01

Cationic magnetic polymer particles Fe3O4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride), a type of potential gene carrier, were prepared by emulsifier-free emulsion polymerization with oleic acid modified magnetite Fe3O4, styrene, butyl acrylate and [2-(methacryloxy)ethyl]trimethylammonium chloride) (METAC). The morphology of the particles was characterized by transmission electron microscopy and the composites of particles were characterized by FT-IR spectroscopy, X-ray diffraction. These results showed that magnetic particles were well dispersed in polymers with the content of about 15%(wt/wt). The composites exhibited superparamagnetism and possessed a certain level of magnetic response. The interactions between the particles with calf-thymus DNA (ct DNA) were confirmed by zeta potential measurement, UV-vis spectroscopy and fluorescence spectroscopy. The DNA-binding capacity determined by the agarose gel electrophoresis showed good binding capacity of the emulsion to DNA. These results suggested the potential of the cationic magnetic polymer emulsion as gene target delivery carrier.

Antibiotic loading and release studies of LSMO nanoparticles embedded in an acrylic polymer

NASA Astrophysics Data System (ADS)

Biswas, Sonali; Keshri, Sunita; Goswami, Sudipta; Isaac, Jinu; Ganguly, Swastika; Perov, Nikolai

2016-12-01

In this paper, we present the drug loading and release works of ? (LSMO) manganite nanoparticles (NPs). The LSMO NPs, grown using the sol-gel method, were embedded in an acrylic interpenetrating polymer network to make the sample applicable for biomedical purposes. The results of scanning electron microscopy showed that these NPs were well dispersed in the polymer. The grain size of these NPs lies in the range of 25-45 nm, as confirmed by transmission electron microscopy. The measurements of DC magnetization and hysteresis loops reveal that the basic magnetic behaviour of the LSMO NPs remained almost unaltered even after embedding in polymer, but with lower saturation value of magnetization. The drug loading and release studies of the grown sample were carried out using an antibiotic, ciprofloxacin. The minimum inhibitory effect of the sample loaded with this drug has exhibited high activity against different strains of bacteria, comparable to the pure ciprofloxacin.

Materials Evaluated as Potential Soil Stabilizers

DTIC Science & Technology

1977-09-01

resin systems including melamines , furfurals, formaldehydes , ureas , sili- cates, acrylamides, vinyls, styrenes, epoxies, and acrylates. Special...CEMENT .. .................. A60 CATEGORY: LIME .. .. ................. A130 CATEGORY: RESIN . .. ................. A155 CATEGORY: SALT...attention was given to calcium acrylate, which had been found unique in developing high strength in very wet soils. This polymer resin was studied extensively

Properties of amylose-oleic acid inclusion complexes from corn starch grafted with poly(methyl acrylate)

USDA-ARS?s Scientific Manuscript database

Corn starch granules have been previously investigated as fillers in polymers. In this study, much smaller particles in the form of spherulites produced by steam jet-cooking high-amylose corn starch and oleic acid to form amylose inclusion complexes were graft polymerized with methyl acrylate, both ...

Asphaltenes-based polymer nano-composites

DOEpatents

Bowen, III, Daniel E

2013-12-17

Inventive composite materials are provided. The composite is preferably a nano-composite, and comprises an asphaltene, or a mixture of asphaltenes, blended with a polymer. The polymer can be any polymer in need of altered properties, including those selected from the group consisting of epoxies, acrylics, urethanes, silicones, cyanoacrylates, vulcanized rubber, phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, imides, esters, cyanate esters, allyl resins.

Multifunctional Polymer Microbubbles for Advanced Sentinel Lymph Node Imaging and Mapping

DTIC Science & Technology

2012-03-01

undesired PMA attached to microbubble surface. Figure 1: One-pot polymer -lipid microbubbles. (a) Synthesis of thiolated poly(acrylic acid) with...Award Number: W81XWH-11-1-0215 TITLE: Multifunctional Polymer Microbubbles for Advanced Sentinel...February 2012 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Multifunctional Polymer Microbubbles for Advanced Sentinel Lymph Node Imaging and Mapping 5b

Proof-of-concept switchable hydrophobic/hydrophilic patterned surfaces from thermo-mechanically tailored acrylate systems

NASA Astrophysics Data System (ADS)

Laursen, Christopher M.

A novel, proof-of-concept, switchable hydrophobic/hydrophilic structured surface targeted to assist in antifouling of materials in aqueous environments was created through the development of a multi-tiered platform. The understructure consists of a thermo-mechanically tailored acrylate based polymer patterned in a pillared array, which was then overlaid with spatially tailored hydrophobic/hydrophilic surface chemistry treatments. Development focused on the synthesis of a ternary acrylate system displaying proper thermo-mechanical behavior in submerged conditions for the understructure, creation of a sufficient soft molding technique, and methods to chemically alter water-surface wetting interactions. The final acrylate based polymer constituents were chosen based on expected low-toxicity and the ability to be photopolymerized, while the final system displayed appropriate mechanical toughness, water absorption, and material stiffness over a select temperature window. This was important as alteration in wettability characteristics relied upon a stark transition in the polymeric materials stiffness within a narrow temperature range. The material qualitatively displayed a more hydrophobic state with the pillared surface structures erect, and a more hydrophilic state with the pillars bent over.

Analysis of Mechanical and Thermogravimetric Properties of Composite Materials Based on PVA/MWCNT and Styrene-Acrylic Copolymer/MWCNT

NASA Astrophysics Data System (ADS)

Volynets, N. I.; Poddubskaya, O. G.; Demidenko, M. I.; Lyubimov, A. G.; Kuzhir, P. P.; Suslyaev, V. I.; Pletnev, M. A.; Zicans, Janis

2017-08-01

Mechanical and thermogravimetric properties of polymer composite materials with various concentrations of multiwalled carbon nanotubes effectively shielding radiation in the radio frequency (20 Hz - 1 MHz) and microwave (26-36 GHz) frequency ranges are studied. As a matrix, widely available polymeric materials, such as polyvinyl acetate and styrene-acrylate, were used in the form of dispersions. From the analysis of the obtained experimental data, it was shown that the introduction of carbon nanotubes into the polymer matrix makes it possible to increase mechanical properties and thermal stability of composite materials.

21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films.

Code of Federal Regulations, 2014 CFR

2014-04-01

... film over one or both sides of a base film produced from one or more of the basic olefin polymers complying with § 177.1520 of this chapter. The base polyolefin film may contain optional adjuvant substances... Limitations (i) Resins and polymers: Acrylic acid polymer and its ethyl or methyl esters Acrylamide...

Organocatalyzed Photocontrolled Radical Polymerization of Semifluorinated (Meth)acrylates Driven by Visible Light.

PubMed

Gong, Honghong; Zhao, Yucheng; Shen, Xianwang; Lin, Jun; Chen, Mao

2018-01-02

Fluorinated polymers are important materials that are widely used in many areas. Herein, we report the development of a metal-free photocontrolled radical polymerization of semifluorinated (meth)acrylates with a new visible-light-absorbing organocatalyst. This method enabled the production of a variety of semifluorinated polymers with narrow molar-weight distributions from semifluorinated trithiocarbonates or perfluoroalkyl iodides. The high performance of "ON/OFF" control and chain-extension experiments further demonstrate the utility and reliability of this method. Furthermore, to streamline the preparation of semifluorinated polymers, a scalable continuous-flow approach has been developed. Given the broad interest in fluorinated materials and photopolymerization, we expect that this method will facilitate the development of advanced materials with unique properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrothermal Growth of ZnO Nanowires on UV-Nanoimprinted Polymer Structures.

PubMed

Park, Sooyeon; Moore, Sean A; Lee, Jaejong; Song, In-Hyouk; Farshchian, Bahador; Kim, Namwon

2018-05-01

Integration of zinc oxide (ZnO) nanowires on miniaturized polymer structures can broaden its application in multi-functional polymer devices by taking advantages of unique physical properties of ZnO nanowires and recent development of polymer microstructures in analytical systems. In this paper, we demonstrate the hydrothermal growth of ZnO nanowires on polymer microstructures fabricated by UV nanoimprinting lithography (NIL) using a polyurethane acrylate (PUA). Since PUA is a siloxane-urethane-acrylate compound containing the alpha-hydroxyl ketone, UV-cured PUA include carboxyl groups, which inhibit and suppress the nucleation and growth of ZnO nanowires on polymer structures. The presence of carboxyl groups in UV-cured PUA was substantiated by Fourier transform infrared spectroscopy (FTIR), and a Ag thin film was deposited on the nanoimprinted polymer structures to limit their inhibitive influence on the growth of ZnO nanowires. Furthermore, the naturally oxidized Ag layer (Ag2O) reduced crystalline lattice mismatches at the interface between ZnO-Ag during the seed annealing process. The ZnO nanowires grown on the Ag-deposited PUA microstructures were found to have comparable morphological characteristics with ZnO nanowires grown on a Si wafer.

21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films.

Code of Federal Regulations, 2012 CFR

2012-04-01

... coating is applied as a continuous film over one or both sides of a base film produced from one or more of the basic olefin polymers complying with § 177.1520 of this chapter. The base polyolefin film may... as are provided: List of substances Limitations (i) Resins and polymers: Acrylic acid polymer and its...

21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films.

Code of Federal Regulations, 2013 CFR

2013-04-01

... coating is applied as a continuous film over one or both sides of a base film produced from one or more of the basic olefin polymers complying with § 177.1520 of this chapter. The base polyolefin film may... as are provided: List of substances Limitations (i) Resins and polymers: Acrylic acid polymer and its...

Desorption of biocides from renders modified with acrylate and silicone.

PubMed

Styszko, Katarzyna; Bollmann, Ulla E; Wangler, Timothy P; Bester, Kai

2014-01-01

Biocides are used in the building industry to prevent algal, bacterial and fungal growth on polymericrenders and thus to protect buildings. However, these biocides are leached into the environment. To better understand this leaching, the sorption/desorption of biocides in polymeric renders was assessed. In this study the desorption constants of cybutryn, carbendazim, iodocarb, isoproturon, diuron, dichloro-N-octylisothiazolinone and tebuconazole towards acrylate and silicone based renders were assessed at different pH values. At pH 9.5 (porewater) the constants for an acrylate based render varied between 8 (isoproturon) and 9634 (iodocarb) and 3750 (dichloro-N-octylisothiazolinone), respectively. The values changed drastically with pH value. The results for the silicone based renders were in a similar range and usually the compounds with high sorption constants for one polymer also had high values for the other polymer. Comparison of the octanol water partitioning constants (Kow) with the render/water partitioning constants (Kd) revealed similarities, but no strong correlation. Adding higher amounts of polymer to the render material changed the equilibria for dichloro-N-octylisothiazolinone, tebuconazole, cybutryn, carbendazim but not for isoproturon and diuron. Copyright © 2013 Elsevier Ltd. All rights reserved.

Continuous process of preparation of n-butyl(meth)acrylate by esterification of (meth)acrylic acid by butanol on thermostable sulfo-cation exchanger

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheleznaya, L.L.; Karakhanov, R.A.; Lunin, A.F.

1987-11-10

The authors propose an effective thermostable sulfo-cation exchanger based on polymers with a system of conjugated bonds, sulfopolyphenylene ketone (SPP) differing from the known cation exchangers by the high thermostability (up to 250/sup 0/C), and also having the effect of the stabilization of the double bond in unsaturated monomers. The combination of inhibiting and cation exchange properties makes it also possible to use these sulfo-cation exchangers in the processes of esterification of (meth)acrylic acids by alcohols without addition of special inhibitors. The SPP catalyst was tested in esterification processes of acrylic an methacrylic acid by butanol at a pilot plant.

Triple-Shape Memory Polymers Based on Self-Complementary Hydrogen Bonding

PubMed Central

Ware, Taylor; Hearon, Keith; Lonnecker, Alexander; Wooley, Karen L.; Maitland, Duncan J.; Voit, Walter

2012-01-01

Triple shape memory polymers (TSMPs) are a growing subset of a class of smart materials known as shape memory polymers, which are capable of changing shape and stiffness in response to a stimulus. A TSMP can change shapes twice and can fix two metastable shapes in addition to its permanent shape. In this work, a novel TSMP system comprised of both permanent covalent cross-links and supramolecular hydrogen bonding cross-links has been synthesized via a one-pot method. Triple shape properties arise from the combination of the glass transition of (meth)acrylate copolymers and the dissociation of self-complementary hydrogen bonding moieties, enabling broad and independent control of both glass transition temperature (Tg) and cross-link density. Specifically, ureidopyrimidone methacrylate and a novel monomer, ureidopyrimidone acrylate, were copolymerized with various alkyl acrylates and bisphenol A ethoxylate diacrylate. Control of Tg from 0 to 60 °C is demonstrated: concentration of hydrogen bonding moieties is varied from 0 to 40 wt %; concentration of the diacrylate is varied from 0 to 30 wt %. Toughness ranges from 0.06 to 0.14 MPa and is found to peak near 20 wt % of the supramolecular cross-linker. A widely tunable class of amorphous triple-shape memory polymers has been developed and characterized through dynamic and quasi-static thermomechanical testing to gain insights into the dynamics of supramolecular networks. PMID:22287811

Degradability of an Acrylate-Linked, Fluorotelomer Polymer in Soil

EPA Science Inventory

Fluorotelomer polymers are used in a broad array of products in modern societies worldwide and, if they degrade at significant rates, potentially are a significant source of perfluorooctanoic acid (PFOA) and related compounds to the environment. To evaluate this possibility, we i...

Multifunctional Polymer Microbubbles for Advanced Sentinel Lymph Node Imaging and Mapping

DTIC Science & Technology

2012-06-01

of thiolated poly(acrylic acid) with fluorescein attached. (b) Bright field image of large bubbles stabilized by polymer and phospholipid...Page 1 of 6 AD_________________ Award Number: W81XWH-11-1-0215 TITLE:   Multifunctional Polymer Microbubbles for Advanced... Polymer Microbubbles for Advanced Sentinel Lymph Node Imaging and Mapping 5b. GRANT NUMBER W81XWH-11-1-0215   5c. PROGRAM ELEMENT NUMBER 6

Molecular weight (hydrodynamic volume) dictates the systemic pharmacokinetics and tumour disposition of PolyPEG star polymers.

PubMed

Khor, Song Yang; Hu, Jinming; McLeod, Victoria M; Quinn, John F; Williamson, Mark; Porter, Christopher J H; Whittaker, Michael R; Kaminskas, Lisa M; Davis, Thomas P

2015-11-01

Herein we report for the first time the biological fate of poly[(oligoethylene glycol) acrylate] (POEGA) star polymers synthesised via a versatile arm-first reversible addition-fragmentation chain transfer (RAFT) polymerisation approach. The biopharmaceutical behaviour of three different molecular weight (49, 64 and 94kDa) POEGA stars was evaluated in rats and nude mice bearing human MDA MB-231 tumours after intravenous administration. The 94kDa star polymer exhibited a longer plasma exposure time than the 49kDa or 64kDa star polymer; an observation attributable to differences in the rates of both polymer biodegradation and urinary excretion. Tumour biodistribution also correlated with molecular weight and was greatest for the longest circulating 94kDa star. Different patterns of liver and spleen biodistribution were observed between mice and rats for the different sized polymers. The polymers were also well-tolerated in vivo and in vitro at therapeutic concentrations. Advances in nanotechnology has enabled scientists to produce nanoparticle as drug carriers in cancer therapeutics. In this article, the authors studied the biological fate of poly[(oligoethylene glycol) acrylate] (POEGA) star polymers of different size, after intravenous injections. This would allow the subsequent comparison to other drug delivery systems for better drug delivery. Copyright © 2015 Elsevier Inc. All rights reserved.

Comparison of Flexural Strength of Different CAD/CAM PMMA-Based Polymers.

PubMed

Alp, Gülce; Murat, Sema; Yilmaz, Burak

2018-01-28

To compare the flexural strength of different computer-aided design/computer-aided manufacturing (CAD/CAM) poly(methyl methacrylate)-based (PMMA) polymers and conventional interim resin materials after thermocycling. Rectangular-shaped specimens (n = 15, for each material) (25 × 2 × 2 mm 3 ) were fabricated from 3 CAD/CAM PMMA-based polymers (Telio CAD [T]; M-PM-Disc [M]; Polident-PMMA [P]), 1 bis-acrylate composite resin (Protemp 4 [PT]), and 1 conventional PMMA (ArtConcept Artegral Dentine [C]) according to ISO 10477:2004 Standards (Dentistry-Polymer-Based Crown and Bridge Materials). The specimens were subjected to 10,000 thermocycles (5 to 55°C). Three-point flexural strength of the specimens was tested in a universal testing machine at a 1.0 mm/min crosshead speed, and the flexural strength data (σ) were calculated (MPa). The flexural strength values were statistically analyzed using 1-way ANOVA, and Tukey HSD post-hoc test for multiple comparisons (α = 0.05). Flexural strength values ranged between 66.1 ± 13.1 and 131.9 ± 19.8 MPa. There were significant differences among the flexural strengths of tested materials, except for between T and P CAD/CAM PMMA-based polymers (p > 0.05). CAD/CAM PMMA-based polymer M had the highest flexural strength and conventional PMMA had the lowest (p < 0.05). CAD/CAM PMMA-based T and P polymers had significantly higher flexural strength than the bis-acrylate composite resin (p < 0.05), and conventional PMMA (p < 0.0001), and significantly lower flexural strength compared to CAD/CAM PMMA-based M (p < 0.05). The flexural strength of CAD/CAM PMMA-based polymers was greater than the flexural strength of bis-acrylate composite resin, which had a greater flexural strength compared to conventional PMMA resin. © 2018 by the American College of Prosthodontists.

Synthesis of Radiation Curable Palm Oil-Based Epoxy Acrylate: NMR and FTIR Spectroscopic Investigations.

PubMed

Salih, Ashraf M; Ahmad, Mansor Bin; Ibrahim, Nor Azowa; Dahlan, Khairul Zaman Hj Mohd; Tajau, Rida; Mahmood, Mohd Hilmi; Yunus, Wan Md Zin Wan

2015-08-04

Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA) from an epoxidized palm oil product (EPOP) as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated.

The protection of different Italian marbles with two partially flourinated acrylic copolymers

NASA Astrophysics Data System (ADS)

Poli, T.; Toniolo, L.; Chiantore, O.

Committing stone protection to polymeric materials started in the sixties but the study and knowledge of the complex and multiple interactions between stone and polymers has only been carried out recently. It's important to note that, together with the factors related to the polymeric system itself, intrinsic properties of the stone substrate, like composition, porosity, and crystalline characteristics, play a relevant role. In this paper the issues related to protection of three different Italian marbles have been investigated: Candoglia marble, employed in the building of the Milan Cathedral, Carrara marble, widely used in sculpture and historical architecture, and S. Giuliano marble, used in the building of the Pisa Cathedral and its famous leaning tower. Specimens coming from blocks of the three quarried stones have been characterized, treated with two new partially fluorinated acrylic copolymers, 2,2,2-trifluoroethyl methacrylate/methyl acrylate (TFEMA/MA), and trifluoromethyl-2,2,2-trifluorethyl methacrylate/methyl acrylate (HFIMA/MA), and tested according to UNI-Normal Italian protocol. All the measurements including capillary water absorption, static contact angles, colour variation, water vapour permeability, and SEM morphological analysis have been carried out before and after the polymeric treatment. The aim of this work is to evaluate the protective efficacy of these two new partially fluorinated acrylic copolymers on the three different marbles, and to correlate the different behaviours with the polymers' properties and with the stone substrates characteristics.

Signal enhancement in ligand-receptor interactions using dynamic polymers at quartz crystal microbalance sensors.

PubMed

Dunér, Gunnar; Anderson, Henrik; Pei, Zhichao; Ingemarsson, Björn; Aastrup, Teodor; Ramström, Olof

2016-06-20

The signal enhancement properties of QCM sensors based on dynamic, biotinylated poly(acrylic acid) brushes has been studied in interaction studies with an anti-biotin Fab fragment. The poly(acrylic acid) sensors showed a dramatic increase in signal response with more than ten times higher signal than the carboxyl-terminated self-assembled monolayer surface.

Controlled aqueous polymerization of acrylamides and acrylates and "in situ" depolymerization in the presence of dissolved CO2.

PubMed

Lloyd, Danielle J; Nikolaou, Vasiliki; Collins, Jennifer; Waldron, Christopher; Anastasaki, Athina; Bassett, Simon P; Howdle, Steven M; Blanazs, Adam; Wilson, Paul; Kempe, Kristian; Haddleton, David M

2016-05-05

Aqueous copper-mediated radical polymerization of acrylamides and acrylates in carbonated water resulted in high monomer conversions (t < 10 min) before undergoing depolymerization (60 min > t > 10 min). The regenerated monomer was characterized and repolymerized following deoxygenation of the resulting solutions to reyield polymers in high conversions that exhibit low dispersities.

Water-Base Coatings

DTIC Science & Technology

1974-11-01

reacted with hydroxypropyl methacrylate and 1-butanol modifier in butyl acrylate -isobutyl methacrylate reactive diluent mixture using dibutyltin dilaurate...disadvantages are: 1. only a few commercial systems (e. g., acrylic resins ) are available; 2. after application, the polymer must somehow be insolubilized...a bisphenol in the presence of an emulsifier and a water-miscible solvent (9); 2. emulsification of an epoxy resin -amine curing agent mixture , e.g

Electron beam-induced graft polymerization of acrylic acid and immobilization of arginine-glycine-aspartic acid-containing peptide onto nanopatterned polycaprolactone.

PubMed

Sun, Hui; Wirsén, Anders; Albertsson, Ann-Christine

2004-01-01

Electron beam- (EB-) induced graft polymerization of acrylic acid and the subsequent immobilization of arginine-glycine-aspartic acid (RGD) peptide onto nanopatterned polycaprolactone with parallel grooves is reported. A high concentration of carboxylic groups was introduced onto the polymer substrate by EB-induced polymerization of acrylic acid. In the coupling of the RGD peptide to the carboxylated polymer surface, a three-step peptide immobilization process was used. This process included the activation of surface carboxylic acid into an active ester intermediate by use of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), the introduction of disulfide groups by use of 2-(2-pyridinyldithio)ethanamine hydrochloride (PDEA), and final immobilization of the peptide via a thiol-disulfide exchange reaction. The extent of coupling was measured by UV spectroscopy. A preliminary study of the in vitro behavior of keratinocytes (NCTC 2544) cultured on the acrylic acid-grafted and RGD peptide-coupled surface showed that most cells grown on the coupled samples had a spread-rounded appearance, while the majority of cells tended to be elongated along the grooves on uncoupled substrates.

Lower critical solution temperature behavior of alpha-substituted poly(acrylic acids)s, cyclopolymerization of N-vinylformamido-methylacrylates, and use of the World-Wide Web in polymer science education

NASA Astrophysics Data System (ADS)

Michalovic, Mark Stephen

A series of alpha-substituted poly(acrylic acid)s was synthesized and characterized. Their aqueous solution properties were investigated with respect to lower critical solution temperature (LCST) behavior. Poly(alpha-methoxymethylacrylic acid) was found to have a lower critical solution temperature (LCST) of 46°C, poly(alpha-methoxyethoxymethylacrylic acid) showed an LCST of 26.5°C and poly(alpha-methoxyethoxyethoxymethylacrylic acid) showed an LCST of 66°C. The cloud points of the solutions of these polymers were found to be sensitive to pH, and to concentrations of additives such as urea, salts, and surfactants. Because of low molecular weight due to chain transfer, high molecular weight analogs of the ether-linked polymers were synthesized in which ester linkages joined the oligo-oxyethylene segment to the acrylate moiety. Poly(alpha-methoxyethoxyacetoxymethylacrylic acid) was the only one of this series to give an LCST with a value of 52.5°C. Copolymers of t-butyl alpha-methoxymethylacrylate (tBMMA) with alpha-(1H,1H- perfluorooctyloxymethyl)acrylic acid (PFOMA) were synthesized, deprotected and their lower critical solution temperatures (LCSTs) evaluated. At PFOMA feed ratios of 0.25 mol % or less, no observable change in the LCST was observed, while at PFOMA feed ratios of above 0.25 mol % to 1.125 mol %, a large linear decrease in the LCST was observed with increasing fluorocarbon content. t-Butyl alpha-(N-vinylformamidomethyl)acrylate (tBVFA) and ethyl alpha-(N-vinylformamidomethyl)acrylate (EVFA) were synthesized from t-butyl alpha-bromomethylacrylate and ethyl alpha-chloromethylacrylate, respectively. tBVFA was found to cyclopolymerize at 120°C in DMF, DMSO, and 1,2-dichlorobenzene at solvent:monomer ratios of 10:1 vol:wt. Molecular weights for poly(tBVFA) ranged from 10,000 to 13,000 as estimated by size-exclusion chromatography. At lower solvent monomer ratio (1:1), and at lower temperature (71°C), crosslinking occurred. EVFA was found to cyclopolymerize, but only in DMF at 122°C and at a 10:1 solvent:monomer ratio. A multimedia educational program called The Macrogalleria dealing with polymer science was created and distributed by the world wide web and on cd-rom. The site is made in the form of a virtual shopping mall in which each store is a lesson on some aspect of polymer science. The lessons are written in informal language to make the material more accessible. Also, the lessons are connected by hypertext links in a nonlinear fashion to allow students to create their own pathways through the material. The Macrogalleria has been very successful, being used by educational institutions to incorporate polymer science into the undergraduate chemistry curriculum, and by many industrial users as well. It has received numerous awards as well.

Preparation of poly(acrylamide-co-acrylic acid)-grafted gum and its flocculation and biodegradation studies.

PubMed

Mittal, H; Mishra, Shivani B; Mishra, A K; Kaith, B S; Jindal, R; Kalia, S

2013-10-15

Biodegradation studies of Gum ghatti (Gg) and acrylamide-co-acrylic acid based flocculants [Gg-cl-poly(AAm-co-AA)] have been reported using the soil composting method. Gg-cl-poly(AAm-co-AA) was found to degrade 89.76% within 60 days. The progress of biodegradation at each stage was monitored through FT-IR and SEM. Polymer was synthesized under pressure using potassium persulphate-ascorbic acid as a redox initiator and N,N'-methylene-bis-acrylamide as a crosslinker. Synthesized polymer was found to show pH, temperature and ionic strength of the cations dependent swelling behavior. Gg-cl-poly(AAm-co-AA) was utilized for the selective absorption of saline from different petroleum fraction-saline emulsions. The flocculation efficiency of the polymer was studied as a function of polymer dose, temperature and pH of the solution. Gg-cl-poly(AAm-co-AA) showed maximum flocculation efficiency with 20 mol L(-1) polymer dose in acidic medium at 50 °C. Copyright © 2013. Published by Elsevier Ltd.

Diels-Alder Trapping of Photochemically Generated o-Quinodimethane Intermediates: An Alternative Route to Photocured Polymer Film Development

NASA Technical Reports Server (NTRS)

Tyson, Daniel S.; Ilhan, Faysal; Meador, Mary Ann B.; Smith, Dee Dee; Scheiman, Daniel A.; Meador, Michael A.

2004-01-01

Photolysis of o-methylphenyl ketones generates bis-o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis-(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate ester monomers for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis-(o-methylphenyl ketone)s and acrylate esters produce thin polymer films. Solid state 13C NMR data indicated 47- 100% reaction of the bis-(o-methylphenyl ketone)s, depending on experimental conditions, to yield the desired products. DSC and TGA analyses were performed to determine the glass transition temperature, T,, and onset of decomposition, Td, of the resulting polymer films. A statistical Design of Experiments approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties.

Preparation and luminescent properties of the novel polymer-rare earth complexes composed of Poly(ethylene-co-acrylic acid) and Europium ions

NASA Astrophysics Data System (ADS)

Wu, Yuewen; Hao, Haixia; Wu, Qingyao; Gao, Zihan; Xie, Hongde

2018-06-01

A series of novel polymer-rare earth complexes with Eu3+ ions have been synthesized and investigated successfully, including the binary complexes containing the single ligand poly(ethylene-co-acrylic acid) (EAA) and the ternary complexes using 1,10-phenanthroline (phen), dibenzoylmethane (DBM) or thenoyltrifluoroacetone (TTA) as the second ligand. Their structures have been characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis and X-ray diffraction (XRD), which confirm that both EAA and small molecules participate in the coordination reaction with rare earth ions, and they can disperse homogeneously in the polymer matrixes. Both ultraviolet-visible (UV-vis) absorption and photoluminescence tests for the complexes have been recorded. The relationship between fluorescence intensity of polymer-rare earth complexes and the quantity of ligand EAA has been studied and discussed. The films casted from the complexes solution can emit strong characteristic red light under UV light excitation. All these results suggest that the complexes possess potential application as luminescent materials.

Recrystallization of water in non-water-soluble (meth)acrylate polymers is not rare and is not devitrification.

PubMed

Gemmei-Ide, Makoto; Ohya, Atsushi; Kitano, Hiromi

2012-02-16

Change in the state of water sorbed into four kinds of non-water-soluble poly(meth)acrylates with low water content by temperature (T) perturbation was examined on the basis of T variable mid-infrared (MIR) spectroscopy. Many studies using differential scanning calorimetry suggested that there was no change in the state. T dependence of their MIR spectra, however, clearly demonstrated various changes in the state. Furthermore, recrystallization, which was crystallization during heating, was observed in all four polymers. The recrystallization observed in this study was not devitrification, which is the change in the state from glassy water to crystalline water, but vapor deposition during heating (vapor re-deposition). There were only two reports about recrystallization of water in a non-water-soluble polymer before this report; therefore, it might be considered to be a rare phenomenon. However, as demonstrated in this study, it is not a rare phenomenon. Recrystallization (vapor re-deposition) of water in the polymer matrices is related to a balance between flexibility and strength of the electrostatic interaction sites of polymer matrices but might not be related to the biocompatibility of polymers.

40 CFR 63.11398 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... acrylonitrile units: acrylic fiber or modacrylic fiber. Acrylonitrile solution polymerization means a process where acrylonitrile and comonomers are dissolved in a solvent to form a polymer solution (typically... resulting reactor polymer solution (spin dope) is filtered and pumped directly to the fiber spinning process...

40 CFR 63.11398 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... acrylonitrile units: acrylic fiber or modacrylic fiber. Acrylonitrile solution polymerization means a process where acrylonitrile and comonomers are dissolved in a solvent to form a polymer solution (typically... resulting reactor polymer solution (spin dope) is filtered and pumped directly to the fiber spinning process...

Volume effect of non-polar solvent towards the synthesis of hydrophilic polymer nanoparticles prepares via inverse miniemulsion polymerization

NASA Astrophysics Data System (ADS)

Kamaruddin, Nur Nasyita; Kassim, Syara; Harun, Noor Aniza

2017-09-01

Polymeric nanoparticles have drawn tremendous attention to researchers and have utilized in diverse fields especially in biomedical applications. Nevertheless, question has raised about the safety and hydrophilicity of the nanoparticles to be utilized in medical and biological applications. One promising solution to this problem is to develop biodegradable polymeric nanoparticles with improve hydrophilicity. This study is focusing to develop safer and "greener" polymeric nanoparticles via inverse miniemulsion polymerization techniques, a robust and convenient method to produce water-soluble polymer nanoparticles. Acrylamide (Am), acrylic acid (AA) and methacrylic acid (MAA) monomers have chosen, as they are biocompatible, non-toxic and ecological. The effect of different volumes of cyclohexane towards the formation of polymer nanoparticles, particle size, particle size distribution and morphology of polymer nanoparticles are investigated. The formation and morphology of polymer nanoparticles are determined using FTIR and SEM respectively. The mean diameters of the polymer nanoparticles were in a range of 80 - 250 nm and with broad particle size distributions as determined by dynamic light scattering (DLS). Hydrophilic polyacrylamide (pAm), poly(acrylic acid) (pAA) and poly(methacrylic acid) (pMAA) nanoparticles were successfully achieved by inverse miniemulsion polymerization and have potentiality to be further utilized in the fabrication of hybrid polymer composite nanoparticles especially in biological and medical applications.

Air Quality Management Using Pollution Prevention: A Joint Service Approach

DTIC Science & Technology

1998-03-01

sites to promote polymerization. High solids coatings may be one or two component systems based on acrylic , alkyd , epoxy, polyester, or urethane...formulation to form high molecular weight polymers. Examples include acrylic , epoxy/polyester hybrid , functional epoxy, thin film epoxy, and urethane...Air Human System Center (HSC/OEBQ) Naval Facilities Engineering Service Center (NFESC) 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 9

PREPARATION OF BLOCK COPOLYMERS OF POLY(STYRENE) AND POLY(T-BUTYL ACRYLATE) OF VARIOUS MOLECULAR WEIGHTS AND ARCHITECTURES BY ATOM TRANSFER RADICAL POLYMERIZATION. (R826735)

EPA Science Inventory

Block copolymers of polystyrene and poly(t-butyl acrylate) were prepared using atom transfer radical polymerization techniques. These polymers were synthesized with a CuBr/N,N,N,NMolecular Probe Fluorescence Monitoring of Polymerization

NASA Technical Reports Server (NTRS)

Bunton, Patrick

2002-01-01

This project investigated the feasibility of using fluorescence spectroscopy to determine viscosity of polymer/monomer in support of Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS). This project will attempt to measure gradient induced flow at a miscible interface during and / or after in-flight polymerization of dodecyl acrylate (lauryl acrylate). Concentration and temperature gradients will be intentionally introduced during polymerization and the resultant fluid flow determined by Particle Imaging Velocimetry (PIV). This report describes an investigation of the feasibility of using fluorescence of a probe molecule to monitor viscosity and/or concentration during and after polymerization. The probe used was pyrene which has been shown to be sensitive to its local environment in methyl methacrylate.

Radiation cured polyester compositions containing metal-properties

NASA Astrophysics Data System (ADS)

Szalińska, H.; Pietrzak, M.; Gonerski, A.

The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them.

Staphylococcus epidermidis biofilm formation and structural organization on different types of intraocular lenses under in vitro flow conditions.

PubMed

Baillif, Stéphanie; Leduff, Frank; Hartmann, Daniel J; Kodjikian, Laurent

2013-01-01

To compare the adherence and structural organization of Staphylococcus epidermidis biofilm on intraocular lenses (IOLs). IOLs made of 3 different biomaterials [polymethyl methacrylate (PMMA), hydrophilic acrylic or hydrophobic acrylic] were incubated into an S. epidermidis bacterial solution. Scanning electron microscopy was used to count the bound bacteria and to analyze the structural biofilm architecture. After 4-6 h of incubation, adherence was statistically weakest on the hydrophilic acrylic polymer. On the hydrophobic acrylic material, the bacterial cells tended to cover the substratum in a horizontal spread in a continuous monolayer. On the hydrophilic acrylic material or on the PMMA material bacterial cells tended to form only few, small scattered cell clusters. The data suggest that the pattern of S. epidermidis adhesion varies with the IOL biomaterial. Hydrophobic IOLs seem to be more permissive to S. epidermidis adhesion. Copyright © 2013 S. Karger AG, Basel.

Evaluations of candidate encapsulation designs and materials for low-cost silicon photovoltaic arrays

NASA Technical Reports Server (NTRS)

Gaines, G. B.; Carmichael, D. C.; Sliemers, F. A.; Brockway, M. C.; Bunk, A. R.; Nance, G. P.

1978-01-01

Three encapsulation designs for silicon photovoltaic arrays based on cells with silk-screened Ag metallization have been evaluated: transparent polymeric coatings over cells laminated between two films or sheets of polymeric materials; cells adhesively bonded to a glass cover with a polymer pottant and a glass or other substrate component. Silicone and acrylic coatings were assessed, together with acrylic sheet, 0.635 mm fiberglass-reinforced polyester sheet, 0.102 mm polycarbonate/acrylic dual-layer film, 0.127 mm fluorocarbon film, soda-lime glass, borosilicate glass, low-iron glass, and several adhesives. The encapsulation materials were characterized by light transmittance measurements, determination of moisture barrier properties and bond strengths, and by the performance of cells before and after encapsulation. Silicon and acrylic coatings provided inadequate protection. Acrylic and fluorocarbon films displayed good weatherability and acceptable optical transmittance. Borosilicate, low-iron and soda-lime-float glasses were found to be acceptable candidate encapsulants for most environments.

Potential Fungus surface resistance of the silica/acrylic coated leaves waste composite

NASA Astrophysics Data System (ADS)

Masturi; Jannah, WN; Maulana, RM; Darsono, T.; Sunarno; Rustad, S.

2018-04-01

The composite coated by some materials coaters have been made. This coating was done to isolate the fungus possibly growing on the composite. The composite was made from a mixture of teak leaves waste and polyurethane polymer using a simple mixing method; then the mixture was pressed at a pressure of 3 metric-tons for 15 minutes. The composite produced then was coated with acrylic only and acrylic-silica using spray method. The coated samples then were characterized using scanning electron microscopy (SEM) to determine the surface pores. Further, it was obtained the average surface pore size of acrylic coater is 1.24 µm, while the acrylic-silica pore forms an oval shape with a length and a width of 0.75 µm and 0.38 µm, respectively. In comparison with the fungus size of 2-7 µm, it can be concluded that the composite is proper as home appliance application.

Novel biobased photo-crosslinked polymer networks prepared from vegetable oil and 2,5-furan diacrylate

USDA-ARS?s Scientific Manuscript database

Novel biobased crosslinked polymer networks were prepared from vegetable oil with 2,5-furan diacrylate as a difunctional stiffener through UV photopolymerization, and the mechanical properties of the resulting films were evaluated. The vegetable oil raw materials used were acrylated epoxidized soybe...

Polymer-gel formation and reformation on irradiation of tertiary-butyl acrylate

NASA Astrophysics Data System (ADS)

Yao, Tiantian; Denkova, Antonia G.; Warman, John M.

2014-04-01

The purpose of the present research was to provide a radiation-chemical basis for the use of tertiary-butyl acrylate gels in radio-fluorogenic dose-imaging applications (Warman et al. 2011a,b, 2013a,b). The radiation-induced polymerization of tertiary-butyl acrylate (TBA) results in the formation of a transparent gel with an optical density lower than 0.1 cm-1 from 600 nm down to 315 nm. The fractional monomer-to-polymer conversion, CM, determined gravimetrically, increases super-linearly with dose, D Gy. Up to CM≈40%, and over the dose rate range D‧=3.5 to 49 cGy s-1, the dose dependence is given by CM=[1+ACM]KD/√D‧ with K=1.43×10-3 Gy-0.5 s-0.5 and A=0.70. For D‧=3.5 cGy s-1 the average polymer size is estimated to be 1.2×105 monomer units or 17 megadalton. For CM≥10% the gel is quasi-rigid, displaying little tendency to flow on a timescale of an hour or more. After removal of monomer by evacuation, the gel can be reformed by adding a volume of monomer to the remaining polymer equal to that removed and allowing this to swell for several days. The dose and dose rate dependence of radiation-induced monomer conversion in the reformed gel show no evidence of a discontinuity caused by the intervening evacuation and reformation procedures.

Preparation and evaluation of microparticles from thiolated polymers via air jet milling.

PubMed

Hoyer, Herbert; Schlocker, Wolfgang; Krum, Kafedjiiski; Bernkop-Schnürch, Andreas

2008-06-01

Microparticles were formulated by incorporation of the model protein horseradish peroxidase in (thiolated) chitosan and (thiolated) poly(acrylic acid) via co-precipitation. Dried protein/polymer complexes were ground with an air jet mill and resulting particles were evaluated regarding size distribution, shape, zeta potential, drug load, protein activity, release pattern, swelling behaviour and cytotoxicity. The mean particle size distribution was 0.5-12 microm. Non-porous microparticles with a smooth surface were prepared. Microparticles from (thiolated) chitosan had a positive charge whereas microparticles from (thiolated) poly(acrylic acid) were negatively charged. The maximum protein load for microparticles based on chitosan, chitosan-glutathione (Ch-GSH), poly(acrylic acid) (PAA) and for poly(acrylic acid)-glutathione (PAA-GSH) was 7+/-1%, 11+/-2%, 4+/-0.2% and 7+/-2%, respectively. The release profile of all microparticles followed a first order release kinetic. Chitosan (0.5mg), Ch-GSH, PAA and PAA-GSH particles showed a 31.4-, 13.8-, 54.2- and a 42.2-fold increase in weight, respectively. No significant cytotoxicity could be found. Thiolated microparticles prepared by jet milling technique were shown to be stable and to have controlled drug release characteristics. After further optimizations the preparation method described here might be a useful tool for the production of protein loaded drug delivery systems.

Optical Input/Electrical Output Memory Elements based on a Liquid Crystalline Azobenzene Polymer.

PubMed

Mosciatti, Thomas; Bonacchi, Sara; Gobbi, Marco; Ferlauto, Laura; Liscio, Fabiola; Giorgini, Loris; Orgiu, Emanuele; Samorì, Paolo

2016-03-01

Responsive polymer materials can change their properties when subjected to external stimuli. In this work, thin films of thermotropic poly(metha)acrylate/azobenzene polymers are explored as active layer in light-programmable, electrically readable memories. The memory effect is based on the reversible modifications of the film morphology induced by the photoisomerization of azobenzene mesogenic groups. When the film is in the liquid crystalline phase, the trans → cis isomerization induces a major surface reorganization on the mesoscopic scale that is characterized by a reduction in the effective thickness of the film. The film conductivity is measured in vertical two-terminal devices in which the polymer is sandwiched between a Au contact and a liquid compliant E-GaIn drop. We demonstrate that the trans → cis isomerization is accompanied by a reversible 100-fold change in the film conductance. In this way, the device can be set in a high- or low-resistance state by light irradiation at different wavelengths. This result paves the way toward the potential use of poly(metha)acrylate/azobenzene polymer films as active layer for optical input/electrical output memory elements.

Advanced clay nanocomposites based on in situ photopolymerization utilizing novel polymerizable organoclays

NASA Astrophysics Data System (ADS)

Kim, Soon Ki

Polymer nanocomposite technology has had significant impact on material design. With the environmental advantages of photopolymerization, a research has recently focused on producing nanocomposites utilizing inexpensive clay particles based on in situ photopolymerization. In this research, novel polymerizable organoclays and thiol-ene photopolymerization have been utilized to develop advanced photopolymer clay nanocomposites and to overcome several limitations in conventional free radical photopolymers. To this end, factors important in nanocomposite processes such as monomer composition, clay dispersion, and photopolymerization behavior in combination with the evolution of ultimate nanocomposite properties have been investigated. For monomer-organoclay compositions, higher chemical compatibility of components induces enhanced clay exfoliation, resulting in photopolymerization rate increases due to an amplified clay template effect. Additionally, by affecting the stoichiometric ratio between thiol and acrylate double bond in the clay gallery, thiolated organoclays enhance thiol-ene copolymerization with increased final thiol conversion while acrylated organoclays encourage acrylate homopolymerization. In accordance with the reaction behavior, incorporation of thiolated organoclays makes polymer chains more flexible with decreased glass transition temperature due to higher formation of thio-ether linkages while adding acrylated organoclays significantly increases the modulus. Photopolymer nanocomposites also help overcome two major drawbacks in conventional free radical photopolymerization, namely severe polymerization shrinkage and oxygen inhibition during polymerization. With addition of a low level of thiol monomers, the oxygen inhibition in various acrylate systems can be overcome by addition of only 5wt% thiolated organoclay. The same amount of polymerizable organoclay also induces up to 90% decreases in the shrinkage stress for acrylate or thiol-acrylate systems. However, nonreactive clays do not reduce the stress substantially and even decreases the polymerization rate in air. Additionally, the clay morphology and polymerization behavior are closely related with evolution of ultimate nanocomposite performance. Use of polymerizable organoclay significantly improves overall toughness of nanocomposites by increasing either modulus or elongation at break based on the type of polymerizable organoclay, which demonstrates the promise of this technology as a modulation and/or optimization tool for nanocomposite properties.

Effects of added surfactant on swelling and molecular transport in drug-loaded tablets based on hydrophobically modified poly(acrylic acid).

PubMed

Knöös, Patrik; Wahlgren, Marie; Topgaard, Daniel; Ulvenlund, Stefan; Piculell, Lennart

2014-08-14

A combination of NMR chemical shift imaging and self-diffusion experiments is shown to give a detailed molecular picture of the events that occur when tablets of hydrophobically modified poly(acrylic acid) loaded with a drug (griseofulvin) swell in water in the presence or absence of surfactant (sodium octylbenzenesulfonate). The hydrophobic substituents on the polymer bind and trap the surfactant molecules in mixed micelles, leading to a slow effective surfactant transport that occurs via a small fraction of individually dissolved surfactant molecules in the water domain. Because of the efficient binding of surfactant, the penetrating water is found to diffuse past the penetrating surfactant into the polymer matrix, pushing the surfactant front outward as the matrix swells. The added surfactant has little effect on the transport of drug because both undissolved solid drug and surfactant-solubilized drug function as reservoirs that essentially follow the polymer as it swells. However, the added surfactant nevertheless has a strong indirect effect on the release of griseofulvin, through the effect of the surfactant on the solubility and erosion of the polymer matrix. The surfactant effectively solubilizes the hydrophobically modified polymer, making it fully miscible with water, leading to a more pronounced swelling and a slower erosion of the polymer matrix.

76 FR 77709 - Butyl acrylate-methacrylic acid-styrene polymer; Tolerance Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-14

... result of pesticide use in residential settings. If EPA is able to determine that a finite tolerance is... integral part of its composition the atomic elements carbon, hydrogen, and oxygen. 3. The polymer does not contain as an integral part of its composition, except as impurities, any element other than those listed...

Polyethylene Glycol-Poly(2-Methyl-5-Vinyl Tetrazole) Polymer Blend (A desensitizing Binder for Propellants and Explosives)

DTIC Science & Technology

1989-03-01

PVA, CTBN , PBAA, PMMA, etc. As a test of this predictability, we dissolved a vinyl acetate polymer in THF, and then added PMVT, and did succeed in...Polyvinyl acetate CTBN Carboxy terminated butadiene acrylonitrile PBAA Polybutadiene acrylic acid PMMA Polymethyl. methacrylate THF Tetrahydrofuran NMR

Synthesis of polymer hybrid latex poly(methyl methacrylate-co-butyl acrylate) with organo montmorillonite via miniemulsion polymerization method for barrier paper

NASA Astrophysics Data System (ADS)

Chanra, J.; Budianto, E.; Soegijono, B.

2018-03-01

Hybrid polymer latex based on combination of organic-inorganic materials, poly(methyl methacrylate-co-butyl acrylate) (PMMBA) and organo-montmorillonite (OMMT) were synthesized via miniemulsion polymerization technique. Modification of montmorillonite (MMT) through the incorporation of myristyltrimethylammonium bromide (MTAB) into the clay’s interlayer spaces were investigated by Small-Angle X-ray Scattering (SAXS), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Transmission Electron Microscopy (TEM). Barrier property and thermal stability of polymer latex film sample were investigated through its Water Vapor Transmission Rate (WVTR) and Thermogravimetric Analysis (TGA). The results indicated that addition of OMMT as filler in PMMBA increased the barrier property and thermal stability of the latex film. Addition of 8.0% (wt) OMMT increased the barrier property and thermal stability. Miniemusion polymerization process with higher addition (>8.0 wt%) of OMMT resulting in high latex viscosity, particle size, and high amount of coagulum. The utilization of this hybrid polymer could benefits paper and board industries to produce high quality barrier paper for food packaging.

Superficial and Inner Examination of a Microwave-Irradiated Dental Acrylic Resin and Its Metal-Polymer Interface.

PubMed

Popescu, Marian C; Bita, Bogdan I; Tucureanu, Vasilica; Vasilache, Dan; Banu, Melania A; Avram, Andrei M; Giurescu-Dumitrescu, Raluca A

2018-02-01

The aim of this study is to conduct an extended surface and cross-section characterization of a denture base acrylic resin subjected to 500, 650, and 750 W microwave irradiation for 2, 3, and 5 min to assess its morphological modifications. A commercial heat-cured powder was polymerized according to the manufacturer's specifications and distributed into 20 circular samples. A stainless-steel wire was partially embedded in half of the discs, in order to investigate the metal-polymer interface. High-resolution scanning electron microscopy (SEM) imaging, white light interferometry, roughness measurements and Fourier transform infrared spectrometry were employed for morphological and structural evaluation of the irradiated polymer. Superficial adaptation was discovered after 5 min exposure at 500 W, 650 W, and 750 W, revealing significant roughness correction for 750 W. SEM characterization revealed the inner alteration of the resin for the 750 W protocol and a metal-polymer gap developed regardless of the irradiation conditions. The considerable temperature fluctuations that the samples were subject to during the experiments did not essentially change the poly(methyl-methacrylate) bond structure.

Stability effect of cholesterol-poly(acrylic acid) in a stimuli-responsive polymer-liposome complex obtained from soybean lecithin for controlled drug delivery.

PubMed

Simões, M G; Alves, P; Carvalheiro, Manuela; Simões, P N

2017-04-01

The development of polymer-liposome complexes (PLCs), in particular for biomedical applications, has grown significantly in the last decades. The importance of these studies comes from the emerging need in finding intelligent controlled release systems, more predictable, effective and selective, for applications in several areas, such as treatment and/or diagnosis of cancer, neurological, dermatological, ophthalmic and orthopedic diseases, gene therapy, cosmetic treatments, and food engineering. This work reports the development and characterization of a pH sensitive system for controlled release based on PLCs. The selected hydrophilic polymer was poly(acrylic acid) (PAA) synthesized by atom transfer radical polymerization (ATRP) with a cholesterol (CHO) end-group to improve the anchoring of the polymer into the lipid bilayer. The polymer was incorporated into liposomes formulated from soybean lecithin and stearylamine, with different stearylamine/phospholipid and polymer/phospholipid ratios (5, 10 and 20%). The developed PLCs were characterized in terms of particle size, polydispersity, zeta potential, release profiles, and encapsulation efficiency. Cell viability studies were performed to assess the cytotoxic potential of PLCs. The results showed that the liposomal formulation with 5% of stearylamine and 10% of polymer positively contribute to the stabilization of the complexes. Afterwards, the carboxylic acid groups of the polymer present at the surface of the liposomes were crosslinked and the same parameters analyzed. The crosslinked complexes showed to be more stable at physiologic conditions. In addition, the release profiles at different pHs (2-12) revealed that the obtained complexes released all their content at acidic conditions. In summary, the main accomplishments of this work are: (i) innovative synthesis of cholesterol-poly(acrylic acid) (CHO-PAA) by ATRP; (ii) stabilization of the liposomal formulation by incorporation of stearylamine and CHO-PAA; (iii) new approach for CHO-PAA crosslinking, resulting in more stable PLCs at physiological conditions; (iv) destabilization of PLCs upon slight changes of pH, showing their pH sensitivity; and (v) the PLCs do not exhibit cellular toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Thiolated and S-protected hydrophobically modified cross-linked poly(acrylic acid)--a new generation of multifunctional polymers.

PubMed

Bonengel, Sonja; Haupstein, Sabine; Perera, Glen; Bernkop-Schnürch, Andreas

2014-10-01

The aim of this study was to create a novel multifunctional polymer by covalent attachment of l-cysteine to the polymeric backbone of hydrophobically modified cross-linked poly(acrylic acid) (AC1030). Secondly, the free thiol groups of the resulting thiomer were activated using 2-mercaptonicotinic acid (2-MNA) to provide full reactivity and stability. Within this study, 1167.36 μmol cysteine and 865.72 μmol 2-MNA could be coupled per gram polymer. Studies evaluating mucoadhesive properties revealed a 4-fold extended adherence time to native small intestinal mucosa for the thiomer (AC1030-cysteine) as well as an 18-fold prolonged adhesion for the preactivated thiomer (AC1030-Cyst-2-MNA) compared to the unmodified polymer. Modification of the polymer led to a higher tablet stability concerning the thiomer and the S-protected thiomer, but a decelerated water uptake could be observed only for the preactivated thiomer. Neither the novel conjugates nor the unmodified polymer showed severe toxicity on Caco-2 cells. Evaluation of emulsification capacity proofed the ability to incorporate lipophilic compounds like medium chain triglycerides and the preservation of the emulsifying properties after the modifications. According to these results thiolated AC1030 as well as the S-protected thiolated polymer might provide a promising tool for solid and semisolid formulations in pharmaceutical development. Copyright © 2014 Elsevier B.V. All rights reserved.

An efficient photochemical route to Pd nanoparticles; application to the one-step synthesis of Pd@polymer nanocomposite films

NASA Astrophysics Data System (ADS)

Wolak, Séverine; Vidal, Loïc; Becht, Jean-Michel; Michelin, Laure; Balan, Lavinia

2016-08-01

We have developed a facile, efficient, low cost and ‘green’ photochemical approach to preparing surfactant-free Pd nanoparticles and Pd-immobilized@acrylate photo-polymer films at room temperature, under air and without any additional treatment. The reaction system only includes a photo-initiator used as a generator of free radicals and a Pd(II) salt. In ethanol solution, the photochemical reduction of Pd(II) to Pd(0) generates very small metal particles with a narrow size distribution (2-4 nm). Furthermore, we have shown that the formation of Pd nanoparticles from a Pd(II) salt can be reversible thus allowing easy handling and safe storage with the possibility of generating the nanoparticles just before use. In the presence of an acrylate bifunctional monomer, Pd@polymer film was obtained through a ‘one-pot, one-step’ process resulting from a simultaneous photo-reduction of Pd(II) and photo-polymerization of acrylate units. The simultaneous generation of a 3D polymer network and of metal particles leads to a homogeneous distribution of Pd nanoparticles in the photo-polymer matrix with an average diameter of approximately 3.7 ± 1.1 nm. Such as-prepared Pd@polymer films were found to efficiently catalyze the Mizoroki-Heck reaction in the presence of only 0.9 mequiv. of supported palladium. The major interest of this arrangement is its recoverability and reusability, which makes it very attractive both from a practical and economical viewpoint. Finally, it is worth noting that this innovation offers a great advantage over concurrent methods in that it is simply generated within minutes, it is highly stable, and there is sharp monodispersity in the size of the Pd nanoparticles that can be stored for months without alteration of their physico-chemical properties and catalytic activity.

Comparison of impact strength of acrylic resin reinforced with kevlar and polyethylene fibres.

PubMed

Kamath, G; Bhargava, K

2002-01-01

The present study was done to evaluate the impact strengths of heat-activated acrylic resins reinforced with Kevlar fibres, polyethylene fibres and unreinforced heat activated acrylic resin. Each of three groups had 25 specimens. Brass rods of uniform length of 40 mm and diameter of 8 mm were used to prepare the moulds. A combination of long fibres (40 mm length) and short fibres (6 mm length) were used. The total amount of fibres incorporated was limited to 2% by weight of the resin matrix. Short and long fibres of equal weight were incorporated. The short fibres were mixed with polymer and monomer and packed into the mould, while, the long axis of the specimen, perpendicular to the applied force. The specimens were then processed. Impact strength testing was done on Hounsfield's impact testing machine. Kevlar fibre reinforced heat activated acrylic resin specimens recorded higher mean impact strength of 0.8464 Joules, while polyethylene fibres reinforced heat activated acrylic resin recorded mean impact strength of 0.7596 joules. The unreinforced heat activated acrylic resin recorded mean impact strength of 0.3440 Joules.

Synthesis of a proline-modified acrylic acid copolymer in supercritical CO2 for glass-ionomer dental cement applications.

PubMed

Moshaverinia, Alireza; Roohpour, Nima; Darr, Jawwad A; Rehman, Ihtesham U

2009-06-01

Supercritical (sc-) fluids (such as sc-CO(2)) represent interesting media for the synthesis of polymers in dental and biomedical applications. Sc-CO(2) has several advantages for polymerization reactions in comparison to conventional organic solvents. It has several advantages in comparison to conventional polymerization solvents, such as enhanced kinetics, being less harmful to the environment and simplified solvent removal process. In our previous work, we synthesized poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone) (PAA-IA-NVP) terpolymers in a supercritical CO(2)/methanol mixture for applications in glass-ionomer dental cements. In this study, proline-containing acrylic acid copolymers were synthesized, in a supercritical CO(2) mixture or in water. Subsequently, the synthesized polymers were used in commercially available glass-ionomer cement formulations (Fuji IX commercial GIC). Mechanical strength (compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS)) and handling properties (working and setting time) of the resulting modified cements were evaluated. It was found that the polymerization reaction in an sc-CO(2)/methanol mixture was significantly faster than the corresponding polymerization reaction in water and the purification procedures were simpler for the former. Furthermore, glass-ionomer cement samples made from the terpolymer prepared in sc-CO(2)/methanol exhibited higher CS and DTS and comparable BFS compared to the same polymer synthesized in water. The working properties of glass-ionomer formulations made in sc-CO(2)/methanol were comparable and better than the values of those for polymers synthesized in water.

Preactivated thiolated poly(methacrylic acid-co-ethyl acrylate): synthesis and evaluation of mucoadhesive potential.

PubMed

Hauptstein, Sabine; Bonengel, Sonja; Rohrer, Julia; Bernkop-Schnürch, Andreas

2014-10-15

The study was aimed to developed and investigate a novel polymer for intestinal drug delivery with improved mucoadhesive properties. Therefore Eudragit® L 100-55 (poly(methacrylic acid-co-ethyl acrylate)) was thiolated by covalent attachment of L-cysteine. The immobilized thiol groups were preactivated by disulfide bond formation with 2-mercaptonicotinic acid. Resulting derivative (Eu-S-MNA) was investigated in terms of mucoadhesion via three different methods: tensile studies, rotating cylinder studies and rheological synergism method, as well as water-uptake capacity and cytotoxicity. Different derivatives were obtained with increasing amount of bound L-cysteine (60, 140 and 266 μmol/g polymer) and degree of preactivation (33, 45 and 51 μmol/g polymer). Tensile studies revealed a 30.5-, 35.3- and 52.2-fold rise of total work of adhesion for the preactivated polymers compared to the unmodified Eudragit. The adhesion time on the rotating cylinder was prolonged up to 17-fold in case of thiolated polymer and up to 34-fold prolonged in case of the preactivated polymer. Rheological synergism revealed remarkable interaction of all investigated modified derivatives with mucus. Further, water-uptake studies showed an over 7h continuing weight gain for the modified polymers whereat disintegration took place for the unmodified polymer within the first hour. Cell viability studies revealed no impact of modification. Accordingly, the novel preactivated thiolated Eudragit-derivative seems to be a promising excipient for intestinal drug delivery. Copyright © 2014 Elsevier B.V. All rights reserved.

Superabsorbent hydrogels via graft polymerization of acrylic acid from chitosan-cellulose hybrid and their potential in controlled release of soil nutrients.

PubMed

Essawy, Hisham A; Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F

2016-08-01

Superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS) yields materials that suffer from poor mechanical strength. Hybridization of chitosan with cellulose (Cell) via chemical bonding using thiourea formaldehyde resin increases the flexibility of the produced hybrid (CTS/Cell). The hybridization process and post graft polymerization of acrylic acid was followed using Fourier transform infrared (FTIR). Also, the obtained structures were homogeneous and exhibited uniform surface as could be shown from imaging with scanning electron microscopy (SEM). Thus, the polymers derived from the grafting of polyacrylic acid from (CTS/Cell) gave rise to much more mechanically robust structures ((CTS/Cell)-g-PAA) that bear wide range of pH response due to presence of chitosan and polyacrylic acid in one homogeneous entity. Additionally, the obtained structures possessed greater water absorbency 390, 39.5g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced retention potential even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high grafting efficiency (GE%), 86.4%, and grafting yield (GY%), 750%. The new superabsorbent polymers proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Cascade synthesis of a gold nanoparticle-network polymer composite

DOE PAGES

Grubjesic, Simonida; Ringstrand, Bryan Scott; Jungjohann, Katherine L.; ...

2015-11-02

In this paper, the multi-step, cascade synthesis of a self-supporting, hierarchically-structured gold nanoparticle hydrogel composite is described. The composite is spontaneously prepared from a non-covalent, lamellar lyotropic mesophase composed of amphiphiles that support the reactive constituents, a mixture of hydroxyl- and acrylate-end-derivatized PEO 117-PPO 47-PEO 117 and [AuCl 4] -. The reaction sequence begins with the auto-reduction of aqueous [AuCl 4] - by PEO 117-PPO 47-PEO 117 which leads to both the production of Au NPs and the free radical initiated polymerization and crosslinking of the acrylate endderivatized PEO 117-PPO 47-PEO 117 to yield a network polymer. Optical spectroscopy andmore » TEM monitored the reduction of [AuCl 4] -, formation of large aggregated Au NPs and oxidative etching into a final state of dispersed, spherical Au NPs. ATR/FT-IR spectroscopy and thermal analysis confirms acrylate crosslinking to yield the polymer network. X-ray scattering (SAXS and WAXS) monitored the evolution of the multilamellar structured mesophase and revealed the presence of semi-crystalline PEO confined within the water layers. The hydrogel could be reversibly swollen without loss of the well-entrained Au NPs with full recovery of composite structure. Finally, optical spectroscopy shows a notable red shift (Δλ~ 45 nm) in the surface plasmon resonance between swollen and contracted states, demonstrating solvent-mediated modulation of the internal NP packing arrangement.« less

Multi-walled carbon nanotubes/polymer composites in absence and presence of acrylic elastomer (ACM).

PubMed

Kumar, S; Rath, T; Mahaling, R N; Mukherjee, M; Khatua, B B; Das, C K

2009-05-01

Polyetherimide/Multiwall carbon nanotube (MWNTs) nanocomposites containing as-received and modified (COOH-MWNT) carbon nanotubes were prepared through melt process in extruder and then compression molded. Thermal properties of the composites were characterized by thermo-gravimetric analysis (TGA). Field emission scanning electron microscopy (FESEM) images showed that the MWNTs were well dispersed and formed an intimate contact with the polymer matrix without any agglomeration. However the incorporation of modified carbon nanotubes formed fascinating, highly crosslinked, and compact network structure throughout the polymer matrix. This showed the increased adhesion of PEI with modified MWNTs. Scanning electron microscopy (SEM) also showed high degree of dispersion of modified MWNTs along with broken ends. Dynamic mechanical analysis (DMA) results showed a marginal increase in storage modulus (E') and glass transition temperature (T(g)) with the addition of MWNTs. Increase in tensile strength and impact strength of composites confirmed the use the MWNTs as possible reinforcement agent. Both thermal and electrical conductivity of composites increased, but effect is more pronounced on modification due to formation of network of carbon nanotubes. Addition of acrylic elastomer to developed PEI/MWNTs (modified) nanocomposites resulted in the further increase in thermal and electrical properties due to the formation of additional bond between MWNTs and acrylic elastomers at the interface. All the results presented are well corroborated by SEM and FESEM studies.

77 FR 32965 - Certain New Chemicals; Receipt and Status Information

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-04

... importer P-12-0214 03/01/2012 05/01/2012 CBI Laundry and auto Carbohydrate polymers dish wash with acrylic... salt (1:2) initiate. P12-0215 03/01/2012 05/01/2012 CBI Laundry and auto Carbohydrate, polymers dish............ 04/25/2012 04/17/2012 (G) Barium, dialkyl 2-sulfobutanedioate phosphate complexes. P-09-0384...

Negative Electrode For An Alkaline Cell

DOEpatents

Coco, Isabelle; Cocciantelli, Jean-Michel; Villenave, Jean-Jacques

1998-07-14

The present invention concerns a negative electrode for an alkaline cell, comprising a current collector supporting a paste containing an electrochemically active material and a binder, characterized in that said binder is a polymer containing hydrophilic and hydrophobic groups, said polymer being selected from an acrylic homopolymer, copolymer and terpolymer, an unsaturated organic acid copolymer and an unsaturated acid anhydride copolymer.

Free Volume Structure of Acrylic-Type Dental Nanocomposites Tested with Annihilating Positrons.

PubMed

Shpotyuk, Olha; Ingram, Adam; Shpotyuk, Oleh

2016-12-01

Positron annihilation spectroscopy in lifetime measuring mode exploring conventional fast-fast coincidence ORTEC system is employed to characterize free volume structure of commercially available acrylic-type dental restorative composite Charisma® (Heraeus Kulzer GmbH, Germany). The measured lifetime spectra for uncured and light-cured composites are reconstructed from unconstrained x3-term fitting and semi-empirical model exploring x3-x2-coupling decomposition algorithm. The governing channel of positron annihilation in the composites studied is ascribed to mixed positron-Ps trapping, where Ps decaying in the third component is caused entirely by input from free-volume holes in polymer matrix, while the second component is defined by free positron trapping in interfacial free-volume holes between filler nanoparticles and surrounded polymer matrix. Microstructure scenario of the photopolymerization shrinkage includes cross-linking of structural chains in polymer matrix followed by conversion of bound positron-electron (positronium) traps in positron-trapping interfacial free-volume voids in a vicinity of agglomerated filler nanoparticles.

Preparation of polyelectrolytes for wastewater treatment.

PubMed

Radoiu, Marilena T; Martin, Diana I; Calinescu, Ioan; Iovu, Horia

2004-01-02

Liquid-phase polymerisation of acrylamide-acrylic acid to form polyelectrolytes used in wastewater cleaning was examined using accelerated electron beam and microwave irradiation methods. Polymerisation was carried out in aqueous solutions at temperatures approximately 60 degrees C. Monomers total concentration was established at 40% (36% acrylamide and 4% acrylic acid). Only using the features of simultaneous radiation-induction and microwave heating can result in the formation of linear polymer chains with good water solubility and low residual monomer concentration. The flocculation capacity of the obtained polymers was tested using two wastewaters, one sampled from a slaughterhouse and the other from a vegetable oil plant. Quality indicators such as total suspended matters (TSM), chemical oxygen demand (COD), biological oxygen demand (BOD) and fat, oils and grease (FOG) were measured before and after the treatment with polymeric flocculants and compared with the results obtained in classical treatment with Al(2)(SO(4))(3). It was found that the combined treatment with polymers and Al(2)(SO(4))(3) increases the degree of purification of both wastewaters up to 99%.

Porous polymer media

DOEpatents

Shepodd, Timothy J.

2002-01-01

Highly crosslinked monolithic porous polymer materials for chromatographic applications. By using solvent compositions that provide not only for polymerization of acrylate monomers in such a fashion that a porous polymer network is formed prior to phase separation but also for exchanging the polymerization solvent for a running buffer using electroosmotic flow, the need for high pressure purging is eliminated. The polymer materials have been shown to be an effective capillary electrochromatographic separations medium at lower field strengths than conventional polymer media. Further, because of their highly crosslinked nature these polymer materials are structurally stable in a wide range of organic and aqueous solvents and over a pH range of 2-12.

Biodegradable starch-based polymeric materials

NASA Astrophysics Data System (ADS)

Suvorova, Anna I.; Tyukova, Irina S.; Trufanova, Elena I.

2000-05-01

The effects of low-molecular-weight additives, temperature and mechanical action on the structure and properties of starch are discussed. Special attention is given to mixtures of starch with synthetic polymers, e.g., co-polymers of ethylene with vinyl acetate, vinyl alcohol, acrylic acid, cellulose derivatives and other natural polymers. These mixtures can be used in the development of novel environmentally safe materials (films, coatings, packaging materials) and various articles for short-term use. The bibliography includes 105 references.

Dewetting acrylic polymer films with water/propylene carbonate/surfactant mixtures - implications for cultural heritage conservation.

PubMed

Baglioni, M; Montis, C; Brandi, F; Guaragnone, T; Meazzini, I; Baglioni, P; Berti, D

2017-09-13

The removal of hydrophobic polymer films from surfaces is one of the top priorities of modern conservation science. Nanostructured fluids containing water, good solvents for polymers, either immiscible or partially miscible with water, and surfactants have been used in the last decade to achieve controlled removal. The dewetting of the polymer film is often an essential step to achieve efficient removal; however, the role of the surfactant throughout the process is yet to be fully understood. We report on the dewetting of a methacrylate/acrylate copolymer film induced by a ternary mixture of water, propylene carbonate (PC) and C 9-11 E 6 , a nonionic alcohol ethoxylate surfactant. The fluid microstructure was characterised through small angle X-ray scattering and the interactions between the film and water, water/PC and water/PC/C 9-11 E 6 , were monitored through confocal laser-scanning microscopy (CLSM) and analised both from a thermodynamic and a kinetic point of view. The presence of a surfactant is a prerequisite to induce dewetting of μm-thick films at room temperature, but it is not a thermodynamic driver. The amphiphile lowers the interfacial energy between the phases and favors the loss of adhesion of the polymer on glass, decreasing, in turn, the activation energy barrier, which can be overcome by the thermal fluctuations of polymer film stability, initiating the dewetting process.

Spacecraft dielectric material properties and spacecraft charging

NASA Technical Reports Server (NTRS)

Frederickson, A. R.; Wall, J. A.; Cotts, D. B.; Bouquet, F. L.

1986-01-01

The physics of spacecraft charging is reviewed, and criteria for selecting and testing semiinsulating polymers (SIPs) to avoid charging are discussed and illustrated. Chapters are devoted to the required properties of dielectric materials, the charging process, discharge-pulse phenomena, design for minimum pulse size, design to prevent pulses, conduction in polymers, evaluation of SIPs that might prevent spacecraft charging, and the general response of dielectrics to space radiation. SIPs characterized include polyimides, fluorocarbons, thermoplastic polyesters, poly(alkanes), vinyl polymers and acrylates, polymers containing phthalocyanine, polyacene quinones, coordination polymers containing metal ions, conjugated-backbone polymers, and 'metallic' conducting polymers. Tables summarizing the results of SIP radiation tests (such as those performed for the NASA Galileo Project) are included.

Uptake and transfection with polymeric nanoparticles are dependent on polymer end-group structure, but largely independent of nanoparticle physical and chemical properties

PubMed Central

Sunshine, Joel C.; Peng, Daniel Y.; Green, Jordan J.

2012-01-01

Development of non-viral particles for gene delivery requires a greater understanding of the properties that enable gene delivery particles to overcome the numerous barriers to intracellular DNA delivery. Linear poly(beta-amino) esters (PBAE) have shown substantial promise for gene delivery, but the mechanism behind their effectiveness is not well quantified with respect to these barriers. In this study, we synthesized, characterized, and evaluated for gene delivery an array of linear PBAEs that differed by small changes along the backbone, side chain, and end-group of the polymers. We examined particle size and surface charge, polymer molecular weight, polymer degradation rate, buffering capacity, cellular uptake, transfection, and cytotoxicity of nanoparticles formulated with these polymers. Significantly, this is the first study that has quantified how small differential structural changes to polymers of this class modulate buffering capacity and polymer degradation rate and relates these findings to gene delivery efficacy. All polymers formed positively charged (zeta potential 21–29 mV) nanosized articles (~ 150 nm). The polymers hydrolytically degraded quickly in physiological conditions, with half-lives ranging from 90 minutes to 6 hours depending on polymer structure. The PBAE buffering capacities in the relevant pH range (pH 5.1 – 7.4) varied from 34% to 95% protonable amines, and on a per mass basis, PBAEs buffered 1.4–4.6 mmol H+/g. When compared to 25 kDa branched polyethyleneimine (PEI), PBAEs buffer significantly fewer protons/mass, as PEI buffers 6.2 mmol H+/g over the same range. However, due to the relatively low cytotoxicity of PBAEs, higher polymer mass can be used to form particles than with PEI and total buffering capacity of PBAE-based particles significantly exceeds that of PEI. Uptake into COS-7 cells ranged from 0% to 95% of cells and transfection ranged from 0% to 93% of cells, depending on the base polymer structure and the end-modifications examined. Five polymers achieved higher uptake and transfection efficacy with less toxicity than branched-PEI control. Surprisingly, acrylate-terminated base polymers were dramatically less efficacious than their end-capped versions, both in terms of uptake (1–3% for acrylate, 75–94% for end-capped) and transfection efficacy (0–1% vs. 20–89%), even though there are minimal differences between acrylate and end-capped polymers in terms of DNA retardation in gel electrophoresis, particle size, zeta potential, and cytotoxicity. These studies further elucidate the role of polymer structure for gene delivery and highlight that small molecule end-group modification of a linear polymer can be critical for cellular uptake in a manner that is largely independent of polymer/DNA binding, particle size, and particle surface charge. PMID:22970908

All acrylic-based thermoplastic elastomers with high upper service temperature and superior mechanical properties

DOE PAGES

Lu, Wei; Wang, Yangyang; Wang, Weiyu; ...

2017-08-25

All acrylic-based thermoplastic elastomers (TPEs) offer potential alternatives to the widely-used styrenic TPEs. However, the high entanglement molecular weight ( M e) of polyacrylates, as compared to polydienes, leads to “disappointing” mechanical performance as compared to styrenic TPEs. In this study, triblock copolymers composed of alkyl acrylates with different pendant groups and different glass transition temperatures ( T gs), i.e. 1-adamatyl acrylate (AdA) and tetrahydrofurfuryl acrylate (THFA), were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. Thermal characterization of the resulting polymers was performed using differential scanning calorimetry (DSC), and the T gs of both segments were observed for themore » block copolymers. This indication of microphase separation behavior was further demonstrated using atomic-force microscopy (AFM) and small angle X-ray scattering (SAXS). Dynamic mechanical analysis (DMA) showed that the softening temperature of the PAdA domains is 123 °C, which is higher than that of both styrenic TPEs and commercial acrylic based TPEs with poly(methyl methacrylate) (PMMA) hard block. Here, the resulting triblock copolymers also exhibited stress–strain behavior superior to that of conventional all acrylic-based TPEs composed of PMMA and poly( n-butyl acrylate) (PBA) made by controlled radical processes, while the tensile strength was lower than for products made by living anionic polymerization.« less

Development of photopolymerizable clay nanocomposites utilizing reactive dispersants

NASA Astrophysics Data System (ADS)

Owusu-Adom, Kwame

Nanocomposites hold tremendous promise for expanding the utility of polymeric materials. However, accessing particulate sizes in the nanoscale domain continues to be a scientific challenge, especially in highly cross-linked photopolymerizable systems. In this study, photopolymerizable nanocomposites utilizing clay nanoparticles and reactive dispersants have been developed. The influence of particle size, dispersant-clay interactions, and surfactant concentration on photopolymerization behavior and nanoparticle dispersion has been elucidated. Clay particles serve as templates upon which surfactants aggregate during photopolymerization. This results in higher photopolymerization rates with addition of increasing concentrations of polymerizable surfactants. Furthermore, polymerizable surfactants induce faster photopolymerization rates compared to non-polymerizable analogues in systems that have ionically-bound dispersants on the particle surface. Utilizing reactive organoclays induces significant changes to the photopolymerization behavior depending on the choice of reactive functionality employed. Faster acrylate photopolymerization rates occur in photopolymer systems containing thiol-modified clays, while much slower rates occur for nonpolymerizable organoclay systems. In addition, chemical compatibility between monomer and clay dispersant (based on chemical similarity or polarity) allows enhancement of exfoliation in photopolymerizable formulations. With polymerizable dispersants, exfoliation is readily achieved in various multifunctional acrylate systems. The degree of exfoliation depends on the position of the reactive group relative to the surfactant's cationic site and the type of functionality. Thiolated organoclays exfoliate during polymerization, while methacrylated clays show substantially less dependence on polymerization behavior. Interestingly, changes in the physical properties of the resulting nanocomposite are independent of the degree of exfoliation in polymerizable organoclay systems. The polymer cross-link density dictates the magnitude of change in both modulus and glass transition temperature of the nanocomposite. Substantial increases in modulus and Tg occur in elastomeric and low cross-link density polymers, while decreases occur in the modulus and Tg of highly cross-linked polymer networks. Finally, these parameters have formed a basis for developing nanocomposites with higher moduli and lower volumetric shrinkage. The photopolymerization rates of these systems are controllable and increase substantially with addition of polymerizable organoclays. Such properties occur in traditional multifunctional acrylate photopolymer systems as well as new binary thiol-(meth)acrylate and ternary thiol-ene-(meth)acrylate photopolymers.

Marginal discrepancy dimensions of single unit metal crowns fabricated by using CAD-CAM-milled acrylate resin polymer blocks or a conventional waxing technique.

PubMed

Lalande, David; Hodd, Jeffrey A; Brousseau, John S; Ramos, Van; Dunham, Daniel; Rueggeberg, Frederick

2017-10-14

Because crowns with open margins are a well-known problem and can lead to complications, it is important to assess the accuracy of margins resulting from the use of a new technique. Currently, data regarding the marginal fit of computer-aided design and computer-aided manufacturing (CAD-CAM) technology to fabricate a complete gold crown (CGC) from a castable acrylate resin polymer block are lacking. The purpose of this in vitro study was to compare marginal discrepancy widths of CGCs fabricated by using either conventional hand waxing or acrylate resin polymer blocks generated by using CAD-CAM technology. A plastic model of a first mandibular molar was prepared by using a 1-mm, rounded chamfer margin on the entire circumference of the tooth. The master die was duplicated 30 times, and 15 wax patterns were fabricated by using a manual waxing technique, and 15 were fabricated by using CAD-CAM technology. All patterns were invested and cast, and resulting CGCs were cemented on their respective die by using resin-modified glass ionomer cement. The specimens were then embedded in acrylic resin and sectioned buccolingually. The buccal and lingual marginal discrepancies of each sectioned portion were measured by using microscopy at ×50 magnification. Data were subjected to repeated measures 2-way ANOVA, by using the Tukey post hoc pairwise comparison test (α=.05). The factor of "technique" had no significant influence on marginal discrepancy measurement (P=.431), but a significant effect of "margin location" (P=.019) was noted. The confounding combination of factors was found to be significantly lower marginal discrepancy dimensions of the lingual margin discrepancy than on the buccal side by using CAD-CAM technology. The marginal discrepancy of CAD-CAM acrylate resin crowns was not significantly different from those made with a conventional manual method; however, lingual margin discrepancies present from CAD-CAM-prepared crowns were significantly less than those measured on the respective buccal surface. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Synthesis and characterisation of new types of side chain cholesteryl polymers.

PubMed

Wang, Bin; Du, Haiyan; Zhang, Junhua

2011-01-01

A series of cholesterol derivatives have been synthesised via the alkylation reaction of the 3-hydroxyl group with the aliphatic bromide compounds with different chain lengths, namely 3β-alkyloxy-cholesterol. The double bond between the C5 and C6 positions in these cholesterol derivatives was oxidised into epoxy, followed by an epoxy-ring-opening reaction with the treatment with acrylic acid, resulting in a series of 3β-alkyloxy-5α-hydroxy-6β-acryloyloxycholesterol, C(n)OCh (n=1, 2, 4, 6, 8, 10, 12), The acrylate group is connected to the C6 position, which is confirmed by the single crystal structure analysis. The corresponding polymers, PC(n)OCh, were prepared via free radical polymerisation. The structure of monomers and the resulting polymers were characterised with nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The thermal properties of PC(n)OCh were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). To determine the secondary structure of polymers, circular dichroism (CD) spectra were performed. It was found that not all monomers produce high-molecular-weight polymers because of steric hindrance. However, all polymers have a helical structure, which can be enhanced by increasing the alkoxy chain length. In addition, increasing the alkoxy chain length decreases the glass transition temperature and increases the decomposition temperature of the polymers. Copyright © 2010 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Wei; Wang, Yangyang; Wang, Weiyu

All acrylic-based thermoplastic elastomers (TPEs) offer potential alternatives to the widely-used styrenic TPEs. However, the high entanglement molecular weight ( M e) of polyacrylates, as compared to polydienes, leads to “disappointing” mechanical performance as compared to styrenic TPEs. In this study, triblock copolymers composed of alkyl acrylates with different pendant groups and different glass transition temperatures ( T gs), i.e. 1-adamatyl acrylate (AdA) and tetrahydrofurfuryl acrylate (THFA), were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. Thermal characterization of the resulting polymers was performed using differential scanning calorimetry (DSC), and the T gs of both segments were observed for themore » block copolymers. This indication of microphase separation behavior was further demonstrated using atomic-force microscopy (AFM) and small angle X-ray scattering (SAXS). Dynamic mechanical analysis (DMA) showed that the softening temperature of the PAdA domains is 123 °C, which is higher than that of both styrenic TPEs and commercial acrylic based TPEs with poly(methyl methacrylate) (PMMA) hard block. Here, the resulting triblock copolymers also exhibited stress–strain behavior superior to that of conventional all acrylic-based TPEs composed of PMMA and poly( n-butyl acrylate) (PBA) made by controlled radical processes, while the tensile strength was lower than for products made by living anionic polymerization.« less

Synthesis and electromechanical characterization of a new acrylic dielectric elastomer with high actuation strain and dielectric strength

NASA Astrophysics Data System (ADS)

Hu, Wei; Niu, Xiaofan; Yang, Xinguo; Zhang, Naifang; Pei, Qibing

2013-04-01

Dielectric Elastomers (DEs) can be actuated under high electric field to produce large strains. Most high-performing DE materials such as the 3M™ VHB™ membranes are commercial products designed for industrial pressure-sensitive adhesives. The limited knowledge of the exact chemical structures of these commercial materials has made it difficult to understand the relationship between molecular structures and electromechanical properties. In this work, new acrylic elastomers based on n-butyl acrylate and acrylic acid were synthesized from monomer solutions by UV-initiated bulk polymerization. The new acrylic copolymers have a potential to obtain high dielectric constant, actuation strain, dielectric strength, and a high energy density. Silicone and ester oligomer diacrylates were also added onto the copolymer structures to suppress crystallization and to crosslink the polymer chains. Four acrylic formulations were developed with different amounts of acrylic acid. This gives a tunable stiffness, while the dielectric constant is varied from 4.3 to 7.1. The figure-of-merit performance of the best formulation is 186 % area strain, 222 MV/m of dielectric strength, and 2.7 MJ/m3 of energy density. To overcome electromechanical instability, different prestrain ratios were investigated, and under the optimized prestrain, the material has a lifetime of thousands of cycles at 120 % area strain.

Photo-Curing: UV Radiation curing of polymers

NASA Technical Reports Server (NTRS)

Inman, Christina A.

2004-01-01

The Polymers Branch of the Materials Division is dedicated to the development of high-performance for a variety of applications. Areas of significant interest include high- temperature polymers, low density, and high strength insulating materials, conductive polymers, and high density polymer electrolytes. This summer our group is working diligently on a photo-curing project. There is interest in the medical community feel the need for a new and improved balloon that will be used for angioplasty (a form of heart surgery). This product should maintain flexibility but add many other properties. Like possibly further processability and resistance to infection. Our group intends on coming up with this product by using photo-enolization (or simply, photo-curing) by Diels-Alder trapping. The main objective was to synthesize a series of new polymers by Diels-Alder cycloaddition of photoenols with more elastomeric properties. Our group was responsible for performing the proper photo-curing techniques of the polymers with diacrylates and bismaleimides, synthesizing novel monomers, and evaluating experimental results. We attempted to use a diacrylate to synthesize the polymer because of previous research done within the Polymers Branch here at NASA. Most acrylates are commercially available, have more elastometric properties than a typical rigid aromatic structure has and they contain ethylene oxides in the middle of their structure that create extensive flexibility. The problem we encountered with the acrylates is that they photo chemically and thermally self polymerize and create diradicals at low temperatures; these constraints caused a lot of unnecessary side reactions. We want to promote solely, diketone polymerization because this type of polymerization has the ability to cause very elastic polymers. We chose to direct our attention towards the usage of maleimides because they are known for eliminating these unnecessary side reactions.

Novel Side-Chain Liquid Cyrstalline Polymers

DTIC Science & Technology

1989-01-01

Synthesis and Characterization of Liquid Crystalline Polyacrylates and Poly- methacrylates Containing Benzyl Ether and Diphenyl Ethane Based Mesogens J...Crystalline Polymethacrylates and Polyacrylates of trans 2-[4-(11- hydroxyundecanyloxy)-3,5-dimethylphenylI-4-(4-methoxyphenyl)-l,3-dioxane Makromol. Chem., 189...and Characterization of Liquid Crystalline Polyacrylates and Poly- met acrylates Containing Benzyl Ether and Diphenyl Ethane Based Mesogens J. Polym

Poly(vinyl alcohol) stabilization of acrylic emulsion polymers using the miniemulsion approach

NASA Astrophysics Data System (ADS)

Kim, Noma

Miniemulsion approach was employed to obtain stable acrylic latexes of n-butyl acrylate and methyl methacrylate (50/50 wt%) stabilized with poly(vinyl alcohol) (PVA) and to enhance the grafting reaction between PVA and acrylic monomers at the water/droplet interface. The stability of miniemulsions were studied in terms of the type and concentration of' the stabilizer, and the PVA partitioning were determined as a function of the PVA concentration. Using the comparison of PVA partitioning at droplet surface and grafted PVA as a function of concentration, it was suggested that the water/monomer interface is the main grafting site in the miniemulsion polymerization. Seeded emulsion and miniemulsion copolymerizations initiated with water-soluble (hydrogen peroxide, HPO), partially water-soluble (t-butyl peroxide, TBHP), and oil-soluble (t-butyl peroxyoctoate, TBPO) initiators were carried out to further investigate the oil/water interface as the grafting site for PVA. The interaction between the capillary wall in the CHDF (capillary hydrodynamic fractionation) chromatographic particle sizer and the water-soluble polymers adsorbed on the particle surface was studied using different types of water-soluble polymers and eluants. Different grafting architectures depending on the initiation site were suggested based on the CHDF results. The amounts of grafted PVA produced in miniemulsion polymers initiated with TBHP and TBPO were substantially less than those in the corresponding seeded emulsion polymerizations. The effect on the internal viscosity at the interface was proposed to explain the difference in grafting in terms of polymerization methods. Aqueous phase and interface grafting were studied using the measurement of the degree of hydrolysis (DH) of the serum PVA and adsorbed PVA after miniemulsion polymerizations. Based on the results, it was found that aqueous phase and interface grafting occurred in the HPO system; however, interface grafting dominated the TBHP system. Colloidal instability in conventional emulsion polymerizations was investigated and compared with the corresponding miniemulsion polymerization. It was found that the grafted PVA in conventional emulsion polymerizations was more hydrophobic presumably due to a greater amount of grafted chains than that in similar miniemulsion polymerizations and this could be correlated with the colloidal instability during conventional emulsion polymerizations.

A remote query magnetoelastic pH sensor.

PubMed

Cai, Q Y; Grimes, C A

2000-11-15

A remote query magnetoelastic pH sensor comprised of a magnetoelastic thick-film coated with a mass-changing pH-responsive polymer is described. In response to a magnetic query field the magnetoelastic sensor mechanically vibrates at a characteristic frequency that is inversely dependent upon the mass of the attached polymer layer. As the magnetoelastic sensor is magnetostrictive the mechanical vibrations of the sensor launch magnetic flux that can be detected remotely from the sensor using a pickup coil. The pH responsive copolymer is synthesized from 20 mol% of acrylic acid and 80 mol% of iso-octyl acrylate and then deposited onto a magnetoelastic film by dip-coating. For a 1 micrometer polymer coating upon a 30 micrometer thick Metglas [The Metglas alloys are a registered trademark of Honeywell Corporation. For product information see: http://www.electronicmaterials.com:80/businesses/sem/amorph/page5_1_2.htm.] alloy 2826MB magnetoelastic film between pH 5 and 9 the change in resonant frequency is linear, approximately 285 Hz/pH or 0.6%/pH. The addition of 10 mmol/l of KCl to the test solution decreases the sensitivity of the polymer approximately 4%. c2000 Elsevier Science B.V. All rights reserved.

Double Modification of Polymer End Groups through Thiolactone Chemistry.

PubMed

Driessen, Frank; Martens, Steven; Meyer, Bernhard De; Du Prez, Filip E; Espeel, Pieter

2016-06-01

A straightforward synthetic procedure for the double modification and polymer-polymer conjugation of telechelic polymers is performed through amine-thiol-ene conjugation. Thiolactone end-functionalized polymers are prepared via two different methods, through controlled radical polymerization of a thiolactone-containing initiator, or by modification of available end-functionalized polymers. Next, these different linear polymers are treated with a variety of amine/acrylate-combinations in a one-pot procedure, creating a library of tailored end-functionalized polymers. End group conversions are monitored via SEC, NMR, and MALDI-TOF analysis, confirming the quantitative modification after each step. Finally, this strategy is applied for the synthesis of block copolymers via polymer-polymer conjugation and the successful outcome is analyzed via LCxSEC measurements. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Brain-Machine-Brain Interface for Rewiring of Cortical Circuitry after Traumatic Brain Injury

DTIC Science & Technology

2011-09-01

parietal bones, and a threaded rod was implanted into the interparietal bone. These were affixed to the skull with dental acrylic. A hybrid, 16...then sealed with a silicone polymer (Kwik-Cast, WPI). The base of the probe connector was lowered onto the dental acrylic and fixed into place. An...the skull using a dental drill with a trephine bit over the cortex contralateral to the dominant forelimb. A total of 14 animals received CCI in the

Surface monolayers of well-defined amphiphilic block copolymer composed of poly(acrylic acid) or poly(oxyethylene) and poly(styrene). Interpolymer complexation at the air-water interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niwa, Masazo; Hayashi, Takehiro; Higashi, Nobuyuki

1990-01-01

Amphiphilic block polymers (2,3) composed of poly(acrylic acid) (PAA) or poly(oxyethylene) (POE) and chain length controlled poly(styrene) (PSt) have been prepared by using a catalytic system of tribromomethyl-terminated oligomer and manganese carbonyl. All the amphiphilic materials formed well-behaved surface monolayers, and the II-A curves for them expanded systematically with an increase of the PSt chain length.

Develop Roll-to-Roll Manufacturing Process of ZrO 2 Nanocrystals/Acrylic Nanocomposites for High Refractive Index Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Pooran C.; Compton, Brett G.; Li, Jianlin

2015-04-01

The purpose of this Cooperative Research and Development Agreement (CRADA) was to develop and evaluate ZrO 2/acrylic nanocomposite coatings for integrated optoelectronic applications. The formulations engineered to be compatible with roll-to-roll process were evaluated in terms of optical and dielectric properties. The uniform distribution of the ZrO 2 nanocrystals in the polymer matrix resulted in highly tunable refractive index and dielectric response suitable for advanced photonic and electronic device applications.

Effect of beverages and mouthwashes on the hardness of polymers used in intraoral prostheses.

PubMed

Goiato, Marcelo Coelho; Dos Santos, Daniela Micheline; Andreotti, Agda Marobo; Nobrega, Adhara Smith; Moreno, Amalia; Haddad, Marcela Filié; Pesqueira, Aldiéris Alves

2014-10-01

The mechanical properties of acrylic resins used in intraoral prostheses may be altered by frequent exposure to liquids such as beverages and mouthwashes. This study aimed to evaluate the effect of thermocycling and liquid immersion on the hardness of four brands of acrylic resins commonly used in removable prostheses (Onda Cryl, QC-20, Clássico, Lucitone). For each brand of resin, seven specimens were immersed in each of six solutions (coffee, cola, red wine, Plax-Colgate, Listerine [LI], Oral B), and seven more were placed in artificial saliva (control). The hardness was tested using a microhardness tester before and after 5000 thermocycles and after 1, 3, 24, 48, and 96 hours of immersion. The results were analyzed using three-way repeated-measures ANOVA and Tukey's test (p < 0.05). The hardness of the resins decreased following thermocycling and immersion in the solutions. Specimens immersed in cola and wine exhibited significant decreases in hardness after immersion for 96 hours, although the greatest significant decrease in hardness occurred in specimens immersed in LI. However, according to American Dental Association specification 12, the Knoop hardness of acrylic resins for intraoral prostheses should not be below 15. Thus, the median values of superficial hardness observed in most of the acrylic resins in this study are considered clinically acceptable. The microhardness of polymers used for intraoral prostheses decreases following thermocycling. Among specimens immersed in beverages, those immersed in cola or wine experienced the greatest decrease in microhardness. Immersion of acrylic resins in LI significantly decreased the microhardness in relation to the initial value. Among the resins assessed, QC-20 exhibited the lowest initial hardness. © 2014 by the American College of Prosthodontists.

Nano-engineered Drug Combinations for Breast Cancer Treatment

DTIC Science & Technology

2013-08-01

dextran),41 or poly(acrylamide-co-acrylic acid ),42 poly(methyl methacrylate),40 poly(styrene),40 and poly(vinyl cinnamate )40, 43, 44 in separate...pH, this polymer is stable and water insoluble, but at acidic pH the polymer becomes de-protected and water-soluble (Figure 6.A). Thus, particles...made of such a polymer will stay intact in the blood stream and will only start to dissolve away and release their cargo in environments with an acidic

Preparation and characterization of polymeric nanocomposite films for application as protective coatings

NASA Astrophysics Data System (ADS)

Gagliardi, S.; Rondino, F.; D'Erme, C.; Persia, F.; Menchini, F.; Santarelli, M. L.; Paulke, B.-R.; Enayati, A. L.; Falconieri, M.

2017-08-01

Addiction of ceramic nanoparticles to acrylic polymers provides a simple and effective means to produce paints with important properties, such as mechanical resistance and tailored wettability, even though for optimal performances, an engineered nanoparticle distribution would be desirable. In this paper we report on the realization and on the morphological and functional characterization of nanocomposites where the nanophase is distributed on the surface of acrylic polymer films, in order to enhance the expression of surface-related properties. To this aim, commercial titanium oxide and silicon oxide nanopowders were dispersed in water and the suspensions were air-sprayed on polymeric films prepared by paint brushing, thus producing a nanostructured ceramic surface coating. Control of the pH of suspensions and acrylic acid functionalization of the surface of titania were used together with high power ultrasonic treatments in order to control dimension of the aggregates in the sprayed suspensions. Optical microscopy, mechanical profilometry, and atomic force microscopy were used to characterize the nanocomposite surface morphology and correlate it to the coating functional properties, evaluated through mechanical abrasion tests and contact angle measurements; also, colorimetry on coated stones was performed in order to test the impact of the coatings on the aesthetical appearance and their photostability under UV irradiation. Results show that the nanostructured ceramic layer slightly improves the resistance of coatings to mechanical abrasion in case of polymer films prepared from latexes. The nanocomposite surface layer does not affect the wettability of the polymer, which remained slightly hydrophilic; this behavior is likely due to inadequate distribution of the nanophase. On the other hand UV-induced superhydrophilicity was observed when the concentration of surface titania nanoparticles is about 0.6 mg/cm2. Colorimetric analysis on historical and Carrara marbles before and after coating evidenced the good transparency of the nanocomposites. Accelerated aging tests permitted to demonstrate that, on the historical marbles, the presence of the nanoparticles has a protective action against UV-induced damage of the underlying polymer film, preventing photodegradation.

Charge-discharge characteristics of nickel/zinc battery with polymer hydrogel electrolyte

NASA Astrophysics Data System (ADS)

Iwakura, Chiaki; Murakami, Hiroki; Nohara, Shinji; Furukawa, Naoji; Inoue, Hiroshi

A new nickel/zinc (Ni/Zn) battery was assembled by using polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and KOH aqueous solution, and its charge-discharge characteristics were investigated. The experimental Ni/Zn cell with the polymer hydrogel electrolyte exhibited well-defined charge-discharge curves and remarkably improved charge-discharge cycle performance, compared to that with a KOH aqueous solution. Moreover, it was found that dendritic growth hardly occurred on the zinc electrode surface during charge-discharge cycles in the polymer hydrogel electrolyte. These results indicate that the polymer hydrogel electrolyte can successfully be used in Ni/Zn batteries as an electrolyte with excellent performance.

Synthesis and Characterization of a Novel Borazine-Type UV Photo-Induced Polymerization of Ceramic Precursors.

PubMed

Wei, Dan; Chen, Lixin; Xu, Tingting; He, Weiqi; Wang, Yi

2016-06-21

A preceramic polymer of B,B',B''-(dimethyl)ethyl-acrylate-silyloxyethyl-borazine was synthesized by three steps from a molecular single-source precursor and characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectrometry. Six-member borazine rings and acrylate groups were effectively introduced into the preceramic polymer to activate UV photo-induced polymerization. Photo-Differential Scanning Calorimetry (Photo-DSC) and real-time FTIR techniques were adapted to investigate the photo-polymerization process. The results revealed that the borazine derivative exhibited dramatic activity by UV polymerization, the double-bond conversion of which reached a maximum in 40 s. Furthermore, the properties of the pyrogenetic products were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD), which proved the ceramic annealed at 1100 °C retained the amorphous phase.

Preparation of hybrid thiol-acrylate emulsion-templated porous polymers by interfacial copolymerization of high internal phase emulsions.

PubMed

Langford, Caitlin R; Johnson, David W; Cameron, Neil R

2015-05-01

Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 μm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication and characterization of shape memory polymers at small-scales

NASA Astrophysics Data System (ADS)

Wornyo, Edem

The objective of this research is to thoroughly investigate the shape memory effect in polymers, characterize, and optimize these polymers for applications in information storage systems. Previous research effort in this field concentrated on shape memory metals for biomedical applications such as stents. Minimal work has been done on shape memory polymers; and the available work on shape memory polymers has not characterized the behaviors of this category of polymers fully. Copolymer shape memory materials based on diethylene glycol dimethacrylate (DEGDMA) crosslinker, and tert butyl acrylate (tBA) monomer are designed. The design encompasses a careful control of the backbone chemistry of the materials. Characterization methods such as dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC); and novel nanoscale techniques such as atomic force microscopy (AFM), and nanoindentation are applied to this system of materials. Designed experiments are conducted on the materials to optimize spin coating conditions for thin films. Furthermore, the recovery, a key for the use of these polymeric materials for information storage, is examined in detail with respect to temperature. In sum, the overarching objectives of the proposed research are to: (i) Design shape memory polymers based on polyethylene glycol dimethacrylate (PEGDMA) and diethylene glycol dimethacrylate (DEGDMA) crosslinkers, 2-hydroxyethyl methacrylate (HEMA) and tert-butyl acrylate monomer (tBA). (ii) Utilize dynamic mechanical analysis (DMA) to comprehend the thermomechanical properties of shape memory polymers based on DEGDMA and tBA. (iii) Utilize nanoindentation and atomic force microscopy (AFM) to understand the nanoscale behavior of these SMPs, and explore the strain storage and recovery of the polymers from a deformed state. (iv) Study spin coating conditions on thin film quality with designed experiments. (iv) Apply neural networks and genetic algorithms to optimize these systems.

Degradation Behaviour of Gamma Irradiated Poly(Acrylic Acid)-graft-Chitosan Superabsorbent Hydrogel

NASA Astrophysics Data System (ADS)

Ria Barleany, Dhena; Ilhami, Alpin; Yusuf Yudanto, Dea; Erizal

2018-03-01

A series of superabsorbent hydrogels were prepared from chitosan and partially neutralized acrylic acid at room temperature by gamma irradiation technique. The effect of irradiation and chitosan addition to the degradation behaviour of polymer were investigated. The gel content, swelling capacity, Equillibrium Degree of Swelling (EDS), Fourier Transform Infra Red (FTIR), and Scanning Electron Microscopy (SEM) study were also performed. Natural degradation in soil and thermal degradation by using of TGA analysis were observed. The variation of chitosan compositions were 0.5, 1, 1.5, and 2 g and the total irradiation doses were 5, 10, 15, and 20 kGy. The highest water capacity of 583.3 g water/g dry hydrogel was resulted from 5 kGy total irradiation dose and 0,5 g addition of chitosan. From the thermal degradation evaluation by using of TGA analysis showed that irradiation dose did not give a significant influence to the degradation rate. The rate of thermal degradation was ranged between 2.42 to 2.55 mg/min. In the natural test of degradation behaviour by using of soil medium, the hydrogel product with chitosan addition was found to have better degradability compared with the poly(acrylic acid) polymer without chitosan.

Thermal and mechanical properties of palm oil-based polyurethane acrylate/clay nanocomposites prepared by in-situ intercalative method and electron beam radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salih, A. M.; Ahmad, Mansor Bin; Ibrahim, Nor Azowa

2014-02-12

Palm oil based-polyurethane acrylate (POBUA)/clay nanocomposites were prepared via in-situ intercalative polymerization using epoxidized palm oil acrylate (EPOLA) and 4,4' methylene diphenyl diisocyante (MDI). Organically modified Montmorillonite (ODA-MMT) was incorporated in EPOLA (1, 3 and 5%wt), and then subjected to polycondensation reaction with MDI. Nanocomposites solid films were obtained successfully by electron beam radiation induced free radical polymerization (curing). FTIR results reveal that the prepolymer was obtained successfully, with nanoclay dispersed in the matrix. The intercalation of the clay in the polymer matrix was investigated by XRD and the interlayer spacing of clay was found to be increased up tomore » 37 Å, while the structure morphology of the nanocomposites was investigated by TEM and SEM. The nanocomposites were found to be a mixture of exfoliated and intercalated morphologies. The thermal stability of the nanocomposites was significantly increased by incorporation of nanoclay into the polymer matrix. DSC results reveal that the Tg was shifted to higher values, gradually with increasing the amount of filler in the nanocomposites. Tensile strength and Young's modulus of the nanocomposites showed remarkable improvement compared to the neat POBUA.« less

Broadband pH-Sensing Organic Transistors with Polymeric Sensing Layers Featuring Liquid Crystal Microdomains Encapsulated by Di-Block Copolymer Chains.

PubMed

Seo, Jooyeok; Song, Myeonghun; Jeong, Jaehoon; Nam, Sungho; Heo, Inseok; Park, Soo-Young; Kang, Inn-Kyu; Lee, Joon-Hyung; Kim, Hwajeong; Kim, Youngkyoo

2016-09-14

We report broadband pH-sensing organic field-effect transistors (OFETs) with the polymer-dispersed liquid crystal (PDLC) sensing layers. The PDLC layers are prepared by spin-coating using ethanol solutions containing 4-cyano-4'-pentyl-biphenyl (5CB) and a diblock copolymer (PAA-b-PCBOA) that consists of LC-philic block [poly(4-cyano-biphenyl-4-oxyundecyl acrylate) (PCBOA)] and acrylic acid block [poly(acrylic acid) (PAA)]. The spin-coated sensing layers feature of 5CB microdomains (<5 μm) encapsulated by the PAA-b-PCBOA polymer chains. The resulting LC-integrated-OFETs (PDLC-i-OFETs) can detect precisely and reproducibly a wide range of pH with only small amounts (10-40 μL) of analyte solutions in both static and dynamic perfusion modes. The positive drain current change is measured for acidic solutions (pH < 7), whereas basic solutions (pH > 7) result in the negative change of drain current. The drain current trend in the present PDLC-i-OFET devices is explained by the shrinking-expanding mechanism of the PAA chains in the diblock copolymer layers.

Invertase immobilization onto radiation-induced graft copolymerized polyethylene pellets

NASA Astrophysics Data System (ADS)

de Queiroz, Alvaro Antonio Alencar; Vitolo, Michele; de Oliveira, Rômulo Cesar; Higa, Olga Zazuco

1996-06-01

The graft copolymer poly(ethylene-g-acrylic acid) (LDPE-g-AA) was prepared by radiation-induced graft copolymerization of acrylic acid onto low density polyethylene (LDPE) pellets, and characterized by infrared photoacoustic spectroscopy and scanning electron microscopy (SEM). The presence of the grafted poly(acrylic acid) (PAA) was established. Invertase was immobilized onto the graft polymer and the thermodynamic parameters of the soluble and immobilized enzyme were determined. The Michaelis constant, Km, and the maximum reaction velocity, Vmax, were determined for the free and the immobilized invertase. The Michaelis constant, Km was larger for the immobilized invertase than for the free enzyme, whereas Vmax was smaller for the immobilized invertase. The thermal stability of the immobilized invertase was higher than that of the free enzyme.

Fabrication and Properties of polyacrylic acid by ionic surfactant disturbance method

NASA Astrophysics Data System (ADS)

Lawan, S.; Osotchan, T.; Chuajiw, W.; Subannajui, K.

2017-09-01

The formation of polymeric materials can be achieved by several methods such as melting and casting, screw extrusion, cross-linking of resin or rubber in a mold, and so on. In this work, the polyacrylic acid is formed by using the emulsion disturbance method. Despite extensively used in the colour painting and coating industries, acrylic emulsion can be processed into a foam and powder configuration by a reaction between acrylic emulsion and salt. The solidification hardly changes the volume between liquid emulsion and solidified polymer which means the final structure of polyacrylic acid is filled with opened air cells. The opened air cell structure is confirmed by the result from scanning electron microscopy. The chemical analysis and crystallography of acrylic powder and foam are examined by Fourier-transform infrared spectroscopy and X-ray diffraction respectively. The phase transformation and Thermal stability are studied by differential scanning calorimetry and thermo gravimetric analysis. Moreover, the mechanical properties of acrylic foam were observed by tensile, compressive and hardness test. In addition to the basic property analysis, acrylic foam was also used in the particle filtration application.

Enzymatic modification of natural and synthetic polymers using lipases and proteases

NASA Astrophysics Data System (ADS)

Chakraborty, Soma

Enzymatic modification of natural/synthetic polymers [starch nanoparticles, poly (n-alkyl acrylates) and poly(vinyl formamide)] was studied. Enzymes used for catalysis were lipases and proteases. Starch nanoparticles (40nm diameter) were incorporated into AOT-coated reverse micelles. Reactions performed with the acylating agents vinyl stearate, epsilon-caprolactone and maleic anhydride in toluene in presence of Novozyme-435 at 40°C for 36h gave products with degrees of substitution of 0.8, 0.6 and 0.4 respectively. DEPT-135 NMR spectra revealed that the modification occurred regioselectively at the C-6 position of the glucose units. Infrared microspectroscopy showed that the surfactant coated starch nanoparticles diffuse into pores of Novozyme-435 beads, coming in close proximity with CALB to promote modification. The modified products retained nanoscale dimensions. Catalysis of amide bond formation between a low molar mass amine and ester side groups of poly(n-alkyl acrylates)[poly(ethyl acrylate), poly(methyl acrylate) and poly(butyl acrylate)] was also examined. The nucleophiles were mono and diamines. Among the poly(n-alkyl acrylates) and the lipases studied, poly(ethyl acrylate) was the preferred substrate and Novozyme-435 the most active lipase. Poly(ethyl acrylate) in 80% by-volume toluene was reacted with 1 equivalent per repeat unit of hexyl amine at 70°C in presence of Novozyme-435. The product contained 10.6 mol% amide groups. Attempts to increase the amidation beyond 10--11 mol% by increasing the reaction time or use of fresh enzyme were unsuccessful, showing that poly(ethylacrylate-co-10mol%hexylacrylamide) is a poor substrate for further acylation. When chiral amines ([R,S]-alpha-methyl benzylamine, [R,S]-beta-methyl phenyl amine) were used as nucleophiles, Novozyme-435 enantioselectively catalyzed amidation of poly(ethyl acrylate). Poly(vinyl formamide), P(VfAm) by acid or base-catalyzed hydrolysis leads to poly(vinylamine), P(VAm), and corresponding copolymers. As an alternative to chemical hydrolysis a mild and selective enzymatic method was discovered. Fifteen proteases were evaluated for this transformation. Of these, PROT 7 was the most active. Within 24h PROT 7 gave products with 44% hydrolysis. Further hydrolysis was not observed by extending the reaction time because poly(vinylformamide-co-40%vinylamine) is a poor substrate for further hydrolysis. The sequence distribution of copolymers formed by chemical hydrolysis and enzymatic hydrolysis was compared. Chemical hydrolysis gave random copolymer. In contrast, PROT 7 gave block-like arrangement of VAm units.

An Examination of Models of Relaxation in Complex Systems. I. Continuous Time Random Walk (CTRW) Models.

DTIC Science & Technology

1986-02-04

Laberge , Phys. Chem. Glasses 14, 122 (1973); F.S. Howell, R. Bose, P.B. Macedo and C.T. Moynihan, J. Phys. Chem. 78, 639 (1974). 30. K.L. Ngai, R.W...J.R. Stevens , J. Polym. Sci.: Polym. Phys. Ed. 17, 1547 (1979); 21, 605 (1983). 41. For Polyethyl acrylate (PEA) see G. Williams and D.C. Watts in

Advanced ultraviolet-resistant silver mirrors for use in solar reflectors

DOEpatents

Jorgensen, Gary J [Pine, CO; Gee, Randy [Arvada, CO

2009-11-03

A silver mirror construction that maintains a high percentage of hemispherical reflectance throughout the UV and visible spectrum when used in solar reflectors, comprising:a) a pressure sensitive adhesive layer positioned beneath a silver overlay;b) a polymer film disposed on the silver overlay;c) an adhesive layer positioned on the polymer film; andd) a UV screening acrylic film disposed on the adhesive layer.

Method for estimating protein binding capacity of polymeric systems.

PubMed

Sharma, Vaibhav; Blackwood, Keith A; Haddow, David; Hook, Lilian; Mason, Chris; Dye, Julian F; García-Gareta, Elena

2015-01-01

Composite biomaterials made from synthetic and protein-based polymers are extensively researched in tissue engineering. To successfully fabricate a protein-polymer composite, it is critical to understand how strongly the protein binds to the synthetic polymer, which occurs through protein adsorption. Currently, there is no cost-effective and simple method for characterizing this interfacial binding. To characterize this interfacial binding, we introduce a simple three-step method that involves: 1) synthetic polymer surface characterisation, 2) a quick, inexpensive and robust novel immuno-based assay that uses protein extraction compounds to characterize protein binding strength followed by 3) an in vitro 2D model of cell culture to confirm the results of the immuno-based assay. Fibrinogen, precursor of fibrin, was adsorbed (test protein) on three different polymeric surfaces: silicone, poly(acrylic acid)-coated silicone and poly(allylamine)-coated silicone. Polystyrene surface was used as a reference. Characterisation of the different surfaces revealed different chemistry and roughness. The novel immuno-based assay showed significantly stronger binding of fibrinogen to both poly(acrylic acid) and poly(allylamine) coated silicone. Finally, cell studies showed that the strength of the interaction between the protein and the polymer had an effect on cell growth. This novel immuno-based assay is a valuable tool in developing composite biomaterials of synthetic and protein-based polymers with the potential to be applied in other fields of research where protein adsorption onto surfaces plays an important role.

Synthesis of N-vinylpyrrolidone modified acrylic acid copolymer in supercritical fluids and its application in dental glass-ionomer cements.

PubMed

Moshaverinia, Alireza; Roohpour, Nima; Billington, Richard W; Darr, Jawwad A; Rehman, Ihtesham U

2008-07-01

Compressed fluids such as supercritical CO(2) offer marvellous opportunities for the synthesis of polymers, particularly in applications in medicine and dentistry. It has several advantages in comparison to conventional polymerisation solvents, such as enhanced kinetics and simplified solvent removal process. In this study, poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone) (PAA-IA-NVP), a modified glass-ionomer polymer, was synthesised in supercritical CO(2) (sc-CO(2)) and methanol as a co-solvent. The synthesised polymer was characterized by (1)H-NMR, Raman and FT-IR spectroscopy and viscometry. The molecular weight of the final product was also measured using static light scattering method. The synthesised polymers were subsequently used in several glass ionomer cement formulations (Fuji II commercial GIC) in which mechanical strength (compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS)) and handling properties (working and setting time) of the resulting cements were evaluated. The polymerisation reaction in sc-CO(2)/methanol was significantly faster than the corresponding polymerisation reaction in water and the purification procedures were simpler for the former. Furthermore, glass ionomer cement samples made from the terpolymer prepared in sc-CO(2)/methanol exhibited higher CS and DTS and comparable BFS compared to the same polymer synthesised in water. The working properties of glass ionomer formulations made in sc-CO(2)/methanol were comparable and in selected cases better than the values of those made from polymers synthesised in water.

Influence of miscibility phenomenon on crystalline polymorph transition in poly(vinylidene fluoride)/acrylic rubber/clay nanocomposite hybrid.

PubMed

Abolhasani, Mohammad Mahdi; Naebe, Minoo; Jalali-Arani, Azam; Guo, Qipeng

2014-01-01

In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules.

Effect of flexibility of grafted polymer on the morphology and property of nanosilica/PVC composites

NASA Astrophysics Data System (ADS)

Zhu, Aiping; Cai, Aiyun; Zhou, Weidong; Shi, Zhehua

2008-04-01

In this study, poly(methyl methacrylate)-grafted-nanosilica (PMMA-g-silica) and a copolymer of styrene (St), n-butyl acrylate (BA) and acrylic acid (AA)-grafted-nanosilica (PSBA-g-silica) hybrid nanoparticles were prepared by using a heterophase polymerization technique in an aqueous system. The grafted polymers made up approximately 50 wt.% of the resulted hybrid nanoparticles which showed a spherical and well-dispersed morphology. The silica hybrid nanoparticles were subsequently used as fillers in a poly(vinyl chloride) (PVC) matrix to fabricate PVC nanocomposite. Morphology study of PVC nanocomposites revealed that both PMMA- and PSBA-grafted-silica had an adhesive interface between the silica and PVC. The tensile strength and elongation to break were found to be improved significantly in comparison with that of untreated nanosilica/PVC composites. Finally our results clearly demonstrated that the properties (e.g. chain flexibility, composition) of the grafted polymer in the hybrid nanoparticles could significantly affect the dispersion behavior of hybrid nanoparticles in PVC matrix, dynamic mechanical thermal properties and mechanical properties of the resulted PVC composites.

Using NMR chemical shift imaging to monitor swelling and molecular transport in drug-loaded tablets of hydrophobically modified poly(acrylic acid): methodology and effects of polymer (in)solubility.

PubMed

Knöös, Patrik; Topgaard, Daniel; Wahlgren, Marie; Ulvenlund, Stefan; Piculell, Lennart

2013-11-12

A new technique has been developed using NMR chemical shift imaging (CSI) to monitor water penetration and molecular transport in initially dry polymer tablets that also contain small low-molecular weight compounds to be released from the tablets. Concentration profiles of components contained in the swelling tablets could be extracted via the intensities and chemical shift changes of peaks corresponding to protons of the components. The studied tablets contained hydrophobically modified poly(acrylic acid) (HMPAA) as the polymer component and griseofulvin and ethanol as hydrophobic and hydrophilic, respectively, low-molecular weight model compounds. The water solubility of HMPAA could be altered by titration with NaOH. In the pure acid form, HMPAA tablets only underwent a finite swelling until the maximum water content of the polymer-rich phase, as confirmed by independent phase studies, had been reached. By contrast, after partial neutralization with NaOH, the polyacid became fully miscible with water. The solubility of the polymer affected the water penetration, the polymer release, and the releases of both ethanol and griseofulvin. The detailed NMR CSI concentration profiles obtained highlighted the clear differences in the disintegration/dissolution/release behavior for the two types of tablet and provided insights into their molecular origin. The study illustrates the potential of the NMR CSI technique to give information of importance for the development of pharmaceutical tablets and, more broadly, for the general understanding of any operation that involves the immersion and ultimate disintegration of a dry polymer matrix in a solvent.

Occupational skin hazards from synthetic plastics.

PubMed

Tosti, A; Guerra, L; Vincenzi, C; Peluso, A M

1993-01-01

Epoxy and acrylic resins have numerous industrial applications but are also widely used in the household environment. These compounds are presently one of the most important sources of occupational contact dermatitis. Contact sensitization to epoxy resins is usually caused by the resin itself but hardeners or other additives, such as reactive diluents, plasticizers, fillers and pigments, can occasionally be responsible. Since completely cured epoxy resins are not sensitizers, epoxy resin sensitization is always due to the presence, in the final polymer, of uncured allergenic low molecular weight oligomers. Acrylates are now considered the fourth most common cause of contact sensitization due to resins. Unpolymerized monomers of acrylic compounds are known to be responsible for the contact allergy. Accelerators, inhibitors and catalysts, which are usually added to the acrylates to promote the polymerization process, can also sensitize. Both allergic and irritant contact dermatitis may be caused by exposure to epoxy or acrylic resins and their additives. Contact urticaria, allergic or irritant airborne contact dermatitis caused by volatile compounds, onychia and paronychia can also occur. From January of 1984 to May of 1992 we detected 39 cases of occupational allergic contact dermatitis to epoxy resin system substances and 11 cases of occupational contact sensitization to acrylic compounds. In our experience, the electronics industry as well as paint and glue related activities were the most important sources of epoxy sensitization. Dental materials and anaerobic sealants were found to be the most frequent acrylate sensitizers.

Patterning methods for polymers in cell and tissue engineering.

PubMed

Kim, Hong Nam; Kang, Do-Hyun; Kim, Min Sung; Jiao, Alex; Kim, Deok-Ho; Suh, Kahp-Yang

2012-06-01

Polymers provide a versatile platform for mimicking various aspects of physiological extracellular matrix properties such as chemical composition, rigidity, and topography for use in cell and tissue engineering applications. In this review, we provide a brief overview of patterning methods of various polymers with a particular focus on biocompatibility and processability. The materials highlighted here are widely used polymers including thermally curable polydimethyl siloxane, ultraviolet-curable polyurethane acrylate and polyethylene glycol, thermo-sensitive poly(N-isopropylacrylamide) and thermoplastic and conductive polymers. We also discuss how micro- and nanofabricated polymeric substrates of tunable elastic modulus can be used to engineer cell and tissue structure and function. Such synergistic effect of topography and rigidity of polymers may be able to contribute to constructing more physiologically relevant microenvironment.

Formation and properties of surface-anchored polymer assemblies with tunable physico-chemical characteristics

NASA Astrophysics Data System (ADS)

Wu, Tao

We describe two new methodologies leading to the formation of novel surface-anchored polymer assemblies on solid substrates. While the main goal is to understand the fundamentals pertaining to the preparation and properties of the surface-bound polymer assemblies (including neutral and chargeable polymers), several examples also are mentioned throughout the Thesis that point out to practical applications of such structures. The first method is based on generating assemblies comprising anchored polymers with a gradual variation of grafting densities on solid substrates. These structures are prepared by first covering the substrate with a molecular gradient of the polymerization initiator, followed by polymerization from these substrate-bound initiator centers ("grafting from"). We apply this technique to prepare grafting density gradients of poly(acryl amide) (PAAm) and poly(acrylic acid) (PAA) on silica-covered substrates. We show that using the grafting density gradient geometry, the characteristics of surface-anchored polymers in both the low grafting density ("mushroom") regime as well as the high grafting density ("brush") regime can be accessed conveniently on a single sample. We use a battery of experimental methods, including Fourier transform infrared spectroscopy (FTIR), Near-edge absorption fine structure spectroscopy (NEXAFS), contact angle, ellipsometry, to study the characteristics of the surface-bound polymer layers. We also probe the scaling laws of neutral polymer as a function of grafting density, and for weak polyelectrolyte, in addition to the grafting density, we study the affect of solution ionic strength and pH values. In the second novel method, which we coined as "mechanically assisted polymer assembly" (MAPA), we form surface anchored polymers by "grafting from" polymerization initiators deposited on elastic surfaces that have been previously extended uniaxially by a certain length increment, Deltax. Upon releasing the strain in the substrate after completion of polymerization, we show the grafting density of the polymers grafted to flexible substrates can be tuned as a function of Deltax.

Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

NASA Technical Reports Server (NTRS)

1979-01-01

A cost effective encapsulant system was identified and a silicone acrylic cover material containing a durable ultraviolet screening agent was prepared. The effectiveness of the cover material in protecting photo-oxidatively sensitive polymers was demonstrated.

Holographic recording medium

NASA Technical Reports Server (NTRS)

Gange, Robert Allen (Inventor)

1977-01-01

A holographic recording medium comprising a conductive substrate, a photoconductive layer and an electrically alterable layer of a linear, low molecular weight hydrocarbon polymer has improved fatigue resistance. An acrylic barrier layer can be interposed between the photoconductive and electrically alterable layers.

Improvement of transmission properties of visible pilot beam for polymer-coated silver hollow fibers with acrylic silicone resin as buffer layer for sturdy structure

NASA Astrophysics Data System (ADS)

Iwai, Katsumasa; Takaku, Hiroyuki; Miyagi, Mitsunobu; Shi, Yi-Wei; Zhu, Xiao-Song; Matsuura, Yuji

2017-02-01

Flexible hollow fibers with 530-μm-bore size were developed for infrared laser delivery. Sturdy hollow fibers were fabricated by liquid-phase coating techniques. A silica glass capillary is used as the substrate. Acrylic silicone resin is used as a buffer layer and the buffer layer is firstly coated on the inner surface of the capillary to protect the glass tube from chemical damages due to the following silver plating process. A silver layer was inner-plated by using the conventional silver mirror-plating technique. To improve adhesion of catalyst to the buffer layer, a surface conditioner has been introduced in the method of silver mirror-plating technique. We discuss improvement of transmission properties of sturdy polymer-coated silver hollow fibers for the Er:YAG laser and red pilot beam delivery.

Charged triblock copolymer self-assembly into charged micelles

NASA Astrophysics Data System (ADS)

Chen, Yingchao; Zhang, Ke; Zhu, Jiahua; Wooley, Karen; Pochan, Darrin; Department of Material Science; Engineering University of Delaware Team; Department of Chemistry Texas A&M University Collaboration

2011-03-01

Micelles were formed through the self-assembly of amphiphlic block copolymer poly(acrylic acid)-block-poly(methyl acrylate)-block-polystyrene (PAA-PMA-PS). ~Importantly, the polymer is complexed with diamine molecules in pure THF solution prior to water titration solvent processing-a critical aspect in the control of final micelle geometry. The addition of diamine triggers acid-base complexation ~between the carboxylic acid PAA side chains and amines. ~Remarkably uniform spheres were found to form close-packed patterns when forced into dried films and thin, solvated films when an excess of amine was used in the polymer assembly process. Surface properties and structural features of these hexagonal-packed spherical micelles with charged corona have been explored by various characterization methods including Transmission Electron Microscopy (TEM), cryogenic TEM, z-potential analysis and Dynamic Light Scattering. The forming mechanism for this pattern and morphology changes against external stimulate such as salt will be discussed.

Extraction of domoic acid from seawater and urine using a resin based on 2-(trifluoromethyl)acrylic acid.

PubMed

Piletska, Elena V; Villoslada, Fernando Navarro; Chianella, Iva; Bossi, Alessandra; Karim, Kal; Whitcombe, Michael J; Piletsky, Sergey A; Doucette, Gregory J; Ramsdell, John S

2008-03-03

A new solid-phase extraction (SPE) matrix with high affinity for the neurotoxin domoic acid (DA) was designed and tested. A computational modelling study led to the selection of 2-(trifluoromethyl)acrylic acid (TFMAA) as a functional monomer capable of imparting affinity towards domoic acid. Polymeric adsorbents containing TFMAA were synthesised and tested in high ionic strength solutions such as urine and seawater. The TFMAA-based polymers demonstrated excellent performance in solid-phase extraction of domoic acid, retaining the toxin while salts and other interfering compounds such as aspartic and glutamic acids were removed by washing and selective elution. It was shown that the TFMAA-based polymer provided the level of purification of domoic acid from urine and seawater acceptable for its quantification by high performance liquid chromatography-mass spectrometry (HPLC-MS) and enzyme-linked immunosorbent assay (ELISA) without any additional pre-concentration and purification steps.

Determination of enrofloxacin by room-temperature phosphorimetry after solid phase extraction on an acrylic polymer sorbent

NASA Astrophysics Data System (ADS)

de Souza, Cabrini F.; Martins, Renata K. S.; da Silva, Andrea R.; da Cunha, Alessandra L. M. C.; Aucélio, Ricardo Q.

A phosphorimetric method was developed to enable the determination of enrofloxacin using photochemical derivatization which was used to both improve detection limits and to minimize the uncertainty of measurements. Phosphorescence was induced on cellulose containing TlNO3. Absolute limit of detection at the ng range and linear analytical response over three orders of magnitude were achieved. A metrological study was made to obtain the combined uncertainty value and to identify that the precision was mainly affected by the changing of substrates when measuring the signal from each replicate. Pharmaceutical formulations containing enrofloxacin were successfully analyzed by the method and the results were similar to the ones achieved using a HPLC method. A solid phase extraction on an acrylic polymer was optimized to separate enrofloxacin from interferents such as diclofenac and other components from biological matrices, which allowed the successful use of the method in urine analysis.

Spatial Frequency Responses of Anisotropic Refractive Index Gratings Formed in Holographic Polymer Dispersed Liquid Crystals

PubMed Central

Fukuda, Yoshiaki; Tomita, Yasuo

2016-01-01

We report on an experimental investigation of spatial frequency responses of anisotropic transmission refractive index gratings formed in holographic polymer dispersed liquid crystals (HPDLCs). We studied two different types of HPDLC materials employing two different monomer systems: one with acrylate monomer capable of radical mediated chain-growth polymerizations and the other with thiol-ene monomer capable of step-growth polymerizations. It was found that the photopolymerization kinetics of the two HPDLC materials could be well explained by the autocatalytic model. We also measured grating-spacing dependences of anisotropic refractive index gratings at a recording wavelength of 532 nm. It was found that the HPDLC material with the thiol-ene monomer gave higher spatial frequency responses than that with the acrylate monomer. Statistical thermodynamic simulation suggested that such a spatial frequency dependence was attributed primarily to a difference in the size of formed liquid crystal droplets due to different photopolymerization mechanisms. PMID:28773314

Spatial Frequency Responses of Anisotropic Refractive Index Gratings Formed in Holographic Polymer Dispersed Liquid Crystals.

PubMed

Fukuda, Yoshiaki; Tomita, Yasuo

2016-03-10

We report on an experimental investigation of spatial frequency responses of anisotropic transmission refractive index gratings formed in holographic polymer dispersed liquid crystals (HPDLCs). We studied two different types of HPDLC materials employing two different monomer systems: one with acrylate monomer capable of radical mediated chain-growth polymerizations and the other with thiol-ene monomer capable of step-growth polymerizations. It was found that the photopolymerization kinetics of the two HPDLC materials could be well explained by the autocatalytic model. We also measured grating-spacing dependences of anisotropic refractive index gratings at a recording wavelength of 532 nm. It was found that the HPDLC material with the thiol-ene monomer gave higher spatial frequency responses than that with the acrylate monomer. Statistical thermodynamic simulation suggested that such a spatial frequency dependence was attributed primarily to a difference in the size of formed liquid crystal droplets due to different photopolymerization mechanisms.

Aqueous film coating to reduce recrystallization of guaifenesin from hot-melt extruded acrylic matrices.

PubMed

Bruce, Caroline D; Fegely, Kurt A; Rajabi-Siahboomi, Ali R; McGinity, James W

2010-02-01

This study investigated the effect of aqueous film coating on the recrystallization of guaifenesin from acrylic, hot-melt extruded matrix tablets. After hot-melt extrusion, matrix tablets were film-coated with either hypromellose or ethylcellulose. The effects of the coating polymer, curing and storage conditions, polymer weight gain, and core guaifenesin concentration on guaifenesin recrystallization were investigated. The presence of either film coating on the guaifenesin-containing tablets was found to prolong the onset time of drug crystallization. The coating polymer was the most important factor determining the delay in the onset of crystallization, with the more hydrophilic polymer, hypromellose, having a higher solubilization potential for the guaifenesin and delaying crystallization for longer period (3 or 6 months in tablets stored at 40 degrees C or 25 degrees C, respectively) than the more hydrophobic ethylcellulose, which displayed a lower solubilization potential for guaifenesin (crystal growth on tablets cured for 2 hours at 60 degrees C occurred within 3 weeks, whereas uncoated tablets displayed surface crystal growth after 30 minutes). Crystal morphology was also affected by the film coating. Elevated temperatures during both curing and storage, incomplete film coalescence, and high core drug concentrations all contributed to an earlier onset of crystal growth.

Synthesis and characterization of gold nanoparticles in a self-assembled ionic liquid polymer nanocomposite

NASA Astrophysics Data System (ADS)

Magurudeniya, Harsha; Ringstrand, Bryan; Jungjohann, Katherine; Firestone, Millicent

Incorporation of nanoparticles(NPs) into polymer matrices has attracted interest, offering a means to create multi-functional materials combining the attributes of polymers (flexibility, processability, mechanical durability) with the opto-electrical properties of NPs. Synthesis of a self-supporting, hierarchically structured Au NP-network polymer was accomplished via a ``one-pot'' reaction employing a mesophase of AuCl3 and an imidazolium based-ionic liquid (IL) containing a acrylate group. In-situ generation of NPs was achieved by reduction of Au3+which in turn yields concomitant initiation of the polymerization of the mesophase. FT-IR and thermal analysis confirmed acrylate cross-linking. X-ray scattering confirms preservation of the mesophase within the NP composite. TEM showed a distribution of the NPs within the composite of primarily non-spherical morphologies. The co-integration of a macromer, PEG diacrylate, served as a reducing agent for the Au and the amount incorporated into the mesophase allowed for manipulation of the swelling factor of the resultant nanocomposite in a ethanol, providing means to modulate the plasmonic resonance of the NPs. This methodology provides means for organizing NPs within the structured regions of the poly(IL) matrix. Such composites may be of interest for photonic/sensing applications.

Multiphoton microscopy of transdermal quantum dot delivery using two photon polymerization-fabricated polymer microneedles

PubMed Central

Gittard, Shaun D; Miller, Philip R; Boehm, Ryan D; Ovsianikov, Aleksandr; Chichkov, Boris N; Heiser, Jeremy; Gordon, John; Monteiro-Riviere, Nancy A; Narayan, Roger J

2010-01-01

Due to their ability to serve as fluorophores and drug delivery vehicles, quantum dots are a powerful tool for theranostics-based clinical applications. In this study, microneedle devices for transdermal drug delivery were fabricated by means of two-photon polymerization of an acrylate-based polymer. We examined proliferation of cells on this polymer using neonatal human epidermal keratinocytes and human dermal fibroblasts. The microneedle device was used to inject quantum dots into porcine skin; imaging of the quantum dots was performed using multiphoton microscopy. PMID:21413181

Ion exchange polymers and method for making

NASA Technical Reports Server (NTRS)

Philipp, Warren H. (Inventor); Street, Kenneth W., Jr. (Inventor)

1994-01-01

An ion exchange polymer comprised of an alkali metal or alkaline earth metal salt of a poly(carboxylic acid) in a poly(vinyl acetal) matrix is described. The polymer is made by treating a mixture made of poly(vinyl alcohol) and poly(acrylic acid) with a suitable aldehyde and an acid catalyst to cause acetalization with some cross-linking. The material is then subjected to an alkaline aqueous solution of an alkali metal salt or an alkali earth metal salt. All of the film forming and cross-linking steps can be carried out simultaneously, if desired.

Synthesis and properties of hydroxy acrylic resin with high solid content

NASA Astrophysics Data System (ADS)

Yu, Zhen; Hu, Mingguang; Cui, Han; Xiao, Jijun

2017-10-01

Manufacturers of automotive repair finishes are tending to reduce more and more the level of volatile organic compounds in their paints in order to comply with increasingly strict environmental legislation. A high solid hydroxy acrylic resin was synthesised using CARDURA E10 and a type of hydroxyacrylic acid resin, its' acid value, hydroxylvalue, viscosity, structure, morphology was measured and film-forming properties after curing were characterised. The results show that the addition of CARDURA E10 in the copolymer composition significantly reduced the viscosity of the polymer system, improved the solid content of the resin and the physical properties of the coating. The hydroxyl acrylate resin with solid content of 90% and excellent comprehensive performance were successfully prepared by controlling the initiator dosage, polymerization temperature and monomer ratio.

Advanced materials for 193-nm resists

NASA Astrophysics Data System (ADS)

Ushirogouchi, Tohru; Asakawa, Koji; Shida, Naomi; Okino, Takeshi; Saito, Satoshi; Funaki, Yoshinori; Takaragi, Akira; Tsutsumi, Kentaro; Nakano, Tatsuya

2000-06-01

Acrylate monomers containing alicyclic side chains featuring a series of polar substituent groups were assumed to be model compounds. Solubility parameters were calculated for the corresponding acrylate polymers. These acrylate monomers were synthesized using a novel aerobic oxidation reaction employing N-hydroxyphtalimide (NHPI) as a catalyst, and then polymerized. These reactions were confirmed to be applicable for the mass-production of those compounds. The calculation results agreed with the hydrophilic parameters measured experimentally. Moreover, the relationship between the resist performance and the above-mentioned solubility parameter has been studied. As a result, a correlation between the resist performance and the calculated solubility parameter was observed. Finally, resolution of 0.13-micron patterns, based on the 1G DRAM design rule, could be successfully fabricated by optimizing the solubility parameter and the resist composition.

Effective holographic recordings in the photopolymer nanocomposites with functionalized silica nanoparticle and polyurethane matrix

NASA Astrophysics Data System (ADS)

Han, Samsook; Lee, Muncheul; Kim, Byung Kyu

2011-11-01

Effective holographic nanocomposites were developed by the surface-functionalized silica nanoparticles and two acrylate monomers/polyurethane (PU) matrix polymer. The functionalization was done with silane compounds carrying long alkyl chain or vinyl group. We evaluated the holographic nanocomposite films by the diffraction efficiency, volume shrinkage, optical loss, and the film morphology. It was found that acrylate monomers/PU system gave higher diffraction efficiency than those of two monomers due to the high refractive index mismatch between the acrylate-rich and PU-rich regions. With the modification of silica particle, up to 35% of particle loading was possible to give a maximum diffraction efficiency of 93.6% for a film of 20 μm in thickness, along with improved refractive index modulation and the sensitivity.

Nanocellular thermoplastic foam and process for making the same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Lingbo; Costeux, Stephane; Patankar, Kshitish A.

Prepare a thermoplastic polymer foam having a porosity of 70% or more and at least one of: (i) an average cell size of 200 nanometers or less; and (ii) a nucleation density of at least 1.times.1015 effective nucleation sites per cubic centimeter of foamable polymer composition not including blowing agent using a foamable polymer composition containing a thermoplastic polymer selected from styrenic polymer and (meth)acrylic polymers, a blowing agent comprising at least 20 mole-percent carbon dioxide based on moles of blowing agent and an additive having a Total Hansen Solubility Parameter that differs from that of carbon dioxide by lessmore » than 2 and that is present at a concentration of 0.01 to 1.5 weight parts per hundred weight parts thermoplastic polymer.« less

pH dependence of the properties of waterborne pressure-sensitive adhesives containing acrylic acid.

PubMed

Wang, Tao; Canetta, Elisabetta; Weerakkody, Tecla G; Keddie, Joseph L; Rivas, Urko

2009-03-01

Polymer colloids are often copolymerized with acrylic acid monomers in order to impart colloidal stability. Here, the effects of the pH on the nanoscale and macroscopic adhesive properties of waterborne poly(butyl acrylate-co-acrylic acid) films are reported. In films cast from acidic colloidal dispersions, hydrogen bonding between carboxylic acid groups dominates the particle-particle interactions, whereas ionic dipolar interactions are dominant in films cast from basic dispersions. Force spectroscopy using an atomic force microscope and macroscale mechanical measurements show that latex films with hydrogen-bonding interactions have lower elastic moduli and are more deformable. They yield higher adhesion energies. On the other hand, in basic latex, ionic dipolar interactions increase the moduli of the dried films. These materials are stiffer and less deformable and, consequently, exhibit lower adhesion energies. The rate of water loss from acidic latex is slower, perhaps because of hydrogen bonding with the water. Therefore, although acid latex offers greater adhesion, there is a limitation in the film formation.

Waterborne polyurethane-acrylic hybrid nanoparticles by miniemulsion polymerization: applications in pressure-sensitive adhesives.

PubMed

Lopez, Aitziber; Degrandi-Contraires, Elise; Canetta, Elisabetta; Creton, Costantino; Keddie, Joseph L; Asua, José M

2011-04-05

Waterborne polyurethane-acrylic hybrid nanoparticles for application as pressure-sensitive adhesives (PSAs) were prepared by one-step miniemulsion polymerization. The addition of polyurethane to a standard waterborne acrylic formulation results in a large increase in the cohesive strength and hence a much higher shear holding time (greater than seven weeks at room temperature), which is a very desirable characteristic for PSAs. However, with the increase in cohesion, there is a decrease in the relative viscous component, and hence there is a decrease in the tack energy. The presence of a small concentration of methyl methacrylate (MMA) in the acrylic copolymer led to phase separation within the particles and created a hemispherical morphology. The tack energy was particularly low in the hybrid containing MMA because of the effects of lower energy dissipation and greater cross-linking. These results highlight the great sensitivity of the viscoelastic and adhesive properties to the details of the polymer network architecture and hence to the precise composition and synthesis conditions.

Well-Defined Macromolecules Using Horseradish Peroxidase as a RAFT Initiase.

PubMed

Danielson, Alex P; Bailey-Van Kuren, Dylan; Lucius, Melissa E; Makaroff, Katherine; Williams, Cameron; Page, Richard C; Berberich, Jason A; Konkolewicz, Dominik

2016-02-01

Enzymatic catalysis and control over macromolecular architectures from reversible addition-fragmentation chain transfer polymerization (RAFT) are combined to give a new method of making polymers. Horseradish peroxidase (HRP) is used to catalytically generate radicals using hydrogen peroxide and acetylacetone as a mediator. RAFT is used to control the polymer structure. HRP catalyzed RAFT polymerization gives acrylate and acrylamide polymers with relatively narrow molecular weight distributions. The polymerization is rapid, typically exceeding 90% monomer conversion in 30 min. Complex macromolecular architectures including a block copolymer and a protein-polymer conjugate are synthesized using HRP to catalytically initiate RAFT polymerization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pharmacokinetics of an oral extended-release formulation of doxycycline hyclate containing acrylic acid and polymethacrylate in dogs.

PubMed

Ruiz, Sara Melisa Arciniegas; Olvera, Lilia Gutiérrez; Chacón, Sara del Carmen Caballero; Estrada, Dinorah Vargas

2015-04-01

To determine the pharmacokinetics of doxycycline hyclate administered orally in the form of experimental formulations with different proportions of acrylic acid-polymethacrylate-based matrices. 30 healthy adult dogs. In a crossover study, dogs were randomly assigned (in groups of 10) to receive a single oral dose (20 mg/kg) of doxycycline hyclate without excipients (control) or extended-release formulations (ERFs) containing doxycycline, acrylic acid polymer, and polymethacrylate in the following proportions: 1:0.5:0.0075 (ERF1) or 1:1:0.015 (ERF2). Serum concentrations of doxycycline were determined for pharmacokinetic analysis before and at several intervals after each treatment. Following oral administration to the study dogs, each ERF resulted in therapeutic serum doxycycline concentrations for 48 hours, whereas the control treatment resulted in therapeutic serum doxycycline concentrations for only 24 hours. All pharmacokinetic parameters for ERF1 and ERF2 were significantly different; however, findings for ERF1 did not differ significantly from those for the control treatment. Results indicated that both ERFs containing doxycycline, acrylic acid polymer, and polymethacrylate had an adequate pharmacokinetic-pharmacodynamic relationship for a time-dependent drug and a longer release time than doxycycline alone following oral administration in dogs. Given the minimum effective serum doxycycline concentration of 0.26 μg/mL, a dose interval of 48 hours can be achieved for each tested ERF. This minimum inhibitory concentration has the potential to be effective against several susceptible bacteria involved in important infections in dogs. Treatment of dogs with either ERF may have several benefits over treatment with doxycycline alone.

Selective separation of fluorinated compounds from complex organic mixtures by pyrolysis-comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry.

PubMed

Nakajima, Yoji; Arinami, Yuko; Yamamoto, Kiyoshi

2014-12-29

The usefulness of comprehensive two-dimensional gas chromatography (GC×GC) was demonstrated for the selective separation of fluorinated compounds from organic mixtures, such as kerosene/perfluorokerosene mixtures, pyrolysis products derived from polyethylene/ethylene-tetrafluoroethylene alternating copolymer mixture and poly[2-(perfluorohexyl)ethyl acrylate]. Perfluorocarbons were completely separated from hydrocarbons in the two-dimensional chromatogram. Fluorohydrocarbons in the pyrolysis products of polyethylene/ethylene-tetrafluoroethylene alternating copolymer mixture were selectively isolated from their hydrocarbon counterparts and regularly arranged according to their chain length and fluorine content in the two-dimensional chromatogram. A reliable structural analysis of the fluorohydrocarbons was achieved by combining effective GC×GC positional information with accurate mass spectral data obtained by high-resolution time-of-flight mass spectrometry (HRTOF-MS). 2-(Perfluorohexyl)ethyl acrylate monomer, dimer, and trimer as well as 2-(perfluorohexyl)ethyl alcohol in poly[2-(perfluorohexyl)ethyl acrylate] pyrolysis products were detected in the bottommost part of the two-dimensional chromatogram with separation from hydrocarbons possessing terminal structure information about the polymer, such as α-methylstyrene. Pyrolysis-GC×GC/HRTOF-MS appeared particularly suitable for the characterization of fluorinated polymer microstructures, such as monomer sequences and terminal groups. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of thiolated poly(acrylic acid) microparticles for the nasal administration of exenatide.

PubMed

Millotti, Gioconda; Vetter, Anja; Leithner, Katharina; Sarti, Federica; Shahnaz Bano, Gul; Augustijns, Patrick; Bernkop-Schnürch, Andreas

2014-12-01

The purpose of this study was to develop a microparticulate formulation for nasal delivery of exenatide utilizing a thiolated polymer. Poly(acrylic acid)-cysteine (PAA-cys) and unmodified PAA microparticles loaded with exenatide were prepared via coprecipitation of the drug and the polymer followed by micronization. Particle size, drug load and release of incorporated exenatide were evaluated. Permeation enhancing properties of the formulations were investigated on excised porcine respiratory mucosa. The viability of the mucosa was investigated by histological studies. Furthermore, ciliary beat frequency (CBF) studies were performed. Microparticles displayed a mean size of 70-80 µm. Drug encapsulation was ∼80% for both thiolated and non-thiolated microparticles. Exenatide was released from both thiolated and non-thiolated particles in comparison to exenatide in buffer only within 40 min. As compared to exenatide dissolved in buffer only, non-thiolated and thiolated microparticles resulted in a 2.6- and 4.7-fold uptake, respectively. Histological studies performed before and after permeation studies showed that the mucosa is not damaged during permeation studies. CBF studies showed that the formulations were cilio-friendly. Based on these results, poly(acrylic acid)-cysteine-based microparticles seem to be a promising approach starting point for the nasal delivery of exenatide.

The Evaluation of Water Sorption/Solubility on Various Acrylic Resins

PubMed Central

Tuna, Suleyman Hakan; Keyf, Filiz; Gumus, Hasan Onder; Uzun, Cengiz

2008-01-01

Objectives The absorption of water by acrylic resins is a phenomenon of considerable importance since it is accompanied by dimensional changes, a further undesirable effect of absorbed water in acrylic resins to reduce the tensile strength of the material. Solubility is also an important property because it represents the mass of soluble materials from the polymers. Methods Ten acrylic resin-based materials were evaluated: two heat cure acrylic resins (De Trey QC-20, Meliodent Heat Cure) and eight self cure acrylic resins (Meliodent Cold, Akrileks, Akribel, Akribel Transparent, Vertex Trayplast, Formatray, Dentalon Plus, Palavit G). To evaluate water sorption and water solubility, thirty square-shaped specimens (20×20×1.5 mm) were fabricated from the wax specimens. One way ANOVA test, Tukey test and Pearson correlation coefficient performed for data. Results Water sorption mean values varied from 11.33±0.33 to 30.46±0.55 μg/mm3. Water solubility mean values varied from −0.05±0.23 to 3.69±0.12 μg/mm3. There was statistically significant difference between mean values of the materials (P<.05). There was no linear correlation between sorption and solubility values. Conclusions The results of the water sorption and water solubility values of both self-cured and heat-cured acrylic resins were in accordance with the ISO specification. No correlation found between water sorption and water solubility values. PMID:19212546

Dosimetry Evolution in Teletherapy: Polimer Gel

NASA Astrophysics Data System (ADS)

Hamann, J. H.; Peixoto, J. G. P.

2018-03-01

Polymer gels evolution and chemical composition used in dosimetry. Type Composition First gels Folin’s Phenol or Gallic Acid Polymer Gel Agarose and N,N’-methylene-bis-acrylamide BANANA Bis, acrylamide, nitrous oxide and agarose BANG-1TM Bis, acrylamide, nitrogen and gelatin BANG-2TM Bis, acrylic acid, sodium hydroxide, nitrogen and gelatin BANG-3TM Bis, methacrylate acid, sodium hydroxide, nitrogen and gelatin MAGIC Methacrylate acid, ascorbic acid, gelatin and copper sulphate

Thiomers--from bench to market.

PubMed

Bonengel, Sonja; Bernkop-Schnürch, Andreas

2014-12-10

Thiolated polymers or designated thiomers are obtained by immobilization of sulhydryl bearing ligands on the polymeric backbone of well-established polymers such as poly(acrylates) or chitosans. This functionalization leads to significantly improved mucoadhesive properties compared to the corresponding unmodified polymers, as disulfide bonds between thiol groups of thiomers and cysteine-rich glycoproteins of the mucus gel layer are formed. Furthermore, enzyme- and efflux-pump inhibiting as well as improved permeation-enhancing properties are advantages of thiolization. By the covalent attachment of mercaptonicotinamide substructures via disulfide bonds to thiolated polymers these properties are even substantially further improved and stability towards oxidation even in aqueous media can be provided. Meanwhile, more than 50 research groups worldwide are working on thiolated polymers. For certain thiomers the scale up process for industrial production has already been done and GMP material is available. Furthermore, safety of thiolated poly(acrylic acid), thiolated chitosan and thiolated hyaluronic acid could be demonstrated via orientating studies in human volunteers and via various clinical trials. The first product (Lacrimera® eye drops, Croma-Pharma) containing a chitosan-N-acetylcysteine conjugate for treatment of dry eye syndrome will enter the European market this year. It is the only product providing a sustained protective effect on the ocular surface due to its comparatively much more prolonged residence time worldwide. Various further products utilizing, for instance, thiolated hyaluronic acid in ocular surgery are in the pipeline. Copyright © 2014 Elsevier B.V. All rights reserved.

Patterning Methods for Polymers in Cell and Tissue Engineering

PubMed Central

Kim, Hong Nam; Kang, Do-Hyun; Kim, Min Sung; Jiao, Alex; Kim, Deok-Ho; Suh, Kahp-Yang

2017-01-01

Polymers provide a versatile platform for mimicking various aspects of physiological extracellular matrix properties such as chemical composition, rigidity, and topography for use in cell and tissue engineering applications. In this review, we provide a brief overview of patterning methods of various polymers with a particular focus on biocompatibility and processability. The materials highlighted here are widely used polymers including thermally curable polydimethyl siloxane, ultraviolet-curable polyurethane acrylate and polyethylene glycol, thermo-sensitive poly(N-isopropylacrylamide) and thermoplastic and conductive polymers. We also discuss how micro- and nanofabricated polymeric substrates of tunable elastic modulus can be used to engineer cell and tissue structure and function. Such synergistic effect of topography and rigidity of polymers may be able to contribute to constructing more physiologically relevant microenvironment. PMID:22258887

Interconnected Porous Polymers with Tunable Pore Throat Size Prepared via Pickering High Internal Phase Emulsions.

PubMed

Xu, Hongyun; Zheng, Xianhua; Huang, Yifei; Wang, Haitao; Du, Qiangguo

2016-01-12

Interconnected macroporous polymers were prepared by copolymerizing methyl acrylate (MA) via Pickering high internal phase emulsion (HIPE) templates with modified silica particles. The pore structure of the obtained polymer foams was observed by field-emission scanning electron microscopy (FE-SEM). Gas permeability was characterized to evaluate the interconnectivity of macroporous polymers. The polymerization shrinkage of continuous phase tends to form open pores while the solid particles surrounding the droplets act as barriers to produce closed pores. These two conflicting factors are crucial in determining the interconnectivity of macroporous polymers. Thus, poly-Pickering HIPEs with high permeability and well-defined pore structure can be achieved by tuning the MA content, the internal phase fraction, and the content of modified silica particles.

Influence of Miscibility Phenomenon on Crystalline Polymorph Transition in Poly(Vinylidene Fluoride)/Acrylic Rubber/Clay Nanocomposite Hybrid

PubMed Central

Abolhasani, Mohammad Mahdi; Naebe, Minoo; Jalali-Arani, Azam; Guo, Qipeng

2014-01-01

In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules. PMID:24551141

Development and characterization of adjustable refractive index scattering epoxy acrylate polymer layers

NASA Astrophysics Data System (ADS)

Eiselt, Thomas; Preinfalk, Jan; Gleißner, Uwe; Lemmer, Uli; Hanemann, Thomas

2017-03-01

Several polymer films for improved optical properties in optoelectronic devices are presented. In such optical applications, it is sometimes important to have a film with an adjusted refractive index, scattering properties, and a low surface roughness. These diffusing films can be used to increase the efficiency of optoelectronic components, such as organic light-emitting diodes. Three different epoxy acrylate mixtures containing Syntholux 291 EA, bisphenol A glycerolate dimethacrylate, and Sartomer SR 348 L are characterized and optimized with different additives. The adjustable refractive index of the material is achieved by chemical doping using 9-vinylcarbazole. Titanium nanoparticles in the mixtures generate light scattering and increase the refractive index additionally. A high-power stirrer is used to mix and disperse all chemical substances together to a homogenous mixture. The viscosity behavior of the mixtures is an important property for the selection of the production method and, therefore, the viscosity measurement results are presented. After the mixing, the monomer mixture is applied on glass substrates by screen printing. To initiate polymerization, the produced films are irradiated for 10 min with ultraviolet radiation and heat. Transmission measurements of the polymer matrix and roughness measurements complement the characterization.

Mitigation of Biofilm Formation on Corrugated Cardboard Fresh Produce Packaging Surfaces Using a Novel Thiazolidinedione Derivative Integrated in Acrylic Emulsion Polymers.

PubMed

Brandwein, Michael; Al-Quntar, Abed; Goldberg, Hila; Mosheyev, Gregory; Goffer, Moshe; Marin-Iniesta, Fulgencio; López-Gómez, Antonio; Steinberg, Doron

2016-01-01

Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analog cardboard packaging using high throughput sequencing technology. We further developed an anti-biofilm polymer meant to coat corrugated cardboard surfaces and mediate bacterial biofilm growth on said surfaces. Integration of a novel thiazolidinedione derivative into the acrylic emulsion polymers was assessed using Energy Dispersive X-ray Spectrometry (EDS) analysis and surface topography was visualized and quantified on corrugated cardboard surfaces. Biofilm growth was measured using q-PCR targeting the gene encoding 16s rRNA. Additionally, architectural structure of the biofilm was observed using SEM. The uniform integration of the thiazolidinedione derivative TZD-6 was confirmed, and it was determined via q-PCR to reduce biofilm growth by ~80% on tested surfaces. A novel and effective method for reducing microbial load and preventing contamination on food packaging is thereby proposed.

Molecularly Imprinted Biodegradable Nanoparticles

NASA Astrophysics Data System (ADS)

Gagliardi, Mariacristina; Bertero, Alice; Bifone, Angelo

2017-01-01

Biodegradable polymer nanoparticles are promising carriers for targeted drug delivery in nanomedicine applications. Molecu- lar imprinting is a potential strategy to target polymer nanoparticles through binding of endogenous ligands that may promote recognition and active transport into specific cells and tissues. However, the lock-and-key mechanism of molecular imprinting requires relatively rigid cross-linked structures, unlike those of many biodegradable polymers. To date, no fully biodegradable molecularly imprinted particles have been reported in the literature. This paper reports the synthesis of a novel molecularly- imprinted nanocarrier, based on poly(lactide-co-glycolide) (PLGA) and acrylic acid, that combines biodegradability and molec- ular recognition properties. A novel three-arm biodegradable cross-linker was synthesized by ring-opening polymerization of glycolide and lactide initiated by glycerol. The resulting macromer was functionalized by introduction of end-functions through reaction with acryloyl chloride. Macromer and acrylic acid were used for the synthesis of narrowly-dispersed nanoparticles by radical polymerization in diluted conditions in the presence of biotin as template molecule. The binding capacity of the imprinted nanoparticles towards biotin and biotinylated bovine serum albumin was twentyfold that of non-imprinted nanoparti- cles. Degradation rates and functional performances were assessed in in vitro tests and cell cultures, demonstrating effective biotin-mediated cell internalization.

[Study on the choice of functional monomer before preparation of myclobutanil molecularly imprinted polymer].

PubMed

Gao, Wen-Hui; Liu, Bo; Li, Xing-Feng; Han, Jun-Hua; Jia, Ying-Min

2014-03-01

To prepare myclobutanil molecularly imprinted polymer, a method was established for the choice of the appropriate functional monomer and its dosage. UV spectra was applied to study the combination form, the effect intensity, the optimal concentration ratio and the numbers of binding sites between myclobutanil and methyl acrylic acid (MAA) or acrylamide (AM) functional monomer. The results showed that hydrogen-bonding interaction could be formed between myclobutanil and methyl acrylic acid (MAA) or acrylamide (AM) functional monomer. The pi electron of the triazole ring conjugated double bond in my clobutanil could transit to pi* conjugate antibonding orbital when it absorbed energy. The formation of hydrogen bond could make pi-->pi* absorption band transit. Maximum absorption wavelength produced red shift with the increase in the functional monomer concentration in the system. The research revealed that the optimal concentration ratios between myclobutanil and the two monomers were c(M):c(MAA) = 1:4, c(M):c(AM) = 1:2. Myclobutanil and the both the functional monomers had the bonding ability, and strong bonding force. The prepared molecularly imprinted polymer using AM as a functional monomer had better stability and specificity of recognition for myclobutanil.

Diffuse polymer interfaces in lobed nanoemulsions preserved in aqueous media.

PubMed

Kim, Ginam; Sousa, Alioscka; Meyers, Deborah; Shope, Marilyn; Libera, Matthew

2006-05-24

Using valence electron energy loss spectroscopy (EELS) in the cryo-scanning transmission electron microscopy (STEM), we found that the polymer-polymer interface in two-phase nanocolloids of polydimethyl siloxane (PDMS) and copolymer (methyl acrylate (MA)-methyl methacrylate (MMA)-vinyl acetate (VA)) preserved in water was diffuse despite the fact that equilibrium thermodynamics indicates it should only be on the order of a few nanometers. The diffuse interface is a result of the kinetic trapping of the copolymer within the PDMS phase, and this finding suggests new nonequilibrium pathways to control interfaces during the synthesis of multicomponent polymeric nanostructures.

Transparent organic/inorganic hybrid sol-gel materials based on perfluorinated polymers and silica

NASA Astrophysics Data System (ADS)

Wojcik, Anna B.; Klein, Lisa C.

1996-01-01

Two types of hybrid gels based on silica and perfluorinated polymers have been prepared. The first type involves a perfluorinated polymer containing acrylate groups. Perfluoropolyether diol diacrylate (PFDA) was functionalized by reacting it with (3-mercapto-propyl) trimethoxysilane by a Michael addition. The resulting silyl derivative (PFDAS) was able to copolymerize with a silica precursor, tetraethylorthosilicate (TEOS), resulting in perfluorinated polymer/silica hybrid gels. For the second type, perfluoroalkylsilane (FAS), vinyltriethoxysilane (VTES), and TEOS were polymerized in one step. In both cases, the gels were transparent, crack-free and water repellent. Since the inorganic and organic components are covalently bonded to each other, these materials can be classified as organic/inorganic copolymers.

Poly(1-adamantyl acrylate): Living Anionic Polymerization, Block Copolymerization, and Thermal Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Wei; Huang, Caili; Hong, Kunlun

Living anionic polymerization of acrylates is challenging due to intrinsic side reactions including backbiting reactions of propagating enolate anions and aggregation of active chain ends. In this study, the controlled synthesis of poly(1-adamatyl acrylate) (PAdA) was performed successfully for the first time via living anionic polymerization through investigation of the initiation systems of sec-butyllithium/diphenylethylene/lithium chloride (sec-BuLi/DPE/LiCl), diphenylmethylpotassium/diethylzinc (DPMK/Et 2Zn), and sodium naphthalenide/dipenylethylene/diethylzinc (Na-Naph/DPE/Et2Zn) in tetrahydrofuran at -78 °C using custom glass-blowing and high-vacuum techniques. PAdA synthesized via anionic polymerization using DPMK with a large excess (more than 40-fold to DPMK) of Et 2Zn as the ligand exhibited predicted molecular weightsmore » from 4.3 to 71.8 kg/mol and polydispersity indices of around 1.10. In addition, the produced PAdAs exhibit a low level of isotactic content (mm triads of 2.1%). The block copolymers of AdA and methyl methacrylate (MMA) were obtained by sequential anionic polymerization, and the distinct living property of PAdA over other acrylates was demonstrated based on the observation that the resulting PAdA-b-PMMA block copolymers were formed with no residual PAdA homopolymer. The PAdA homopolymers exhibit a very high glass transition temperature (133 °C) and outstanding thermal stability (T d: 376 °C) as compared to other acrylic polymers such as poly(tert-butyl acrylate) and poly(methyl acrylate). These merits make PAdA a promising candidate for acrylic-based thermoplastic elastomers with high upper service temperature and enhanced mechanical strength.« less

Poly(1-adamantyl acrylate): Living Anionic Polymerization, Block Copolymerization, and Thermal Properties

DOE PAGES

Lu, Wei; Huang, Caili; Hong, Kunlun; ...

2016-12-06

Living anionic polymerization of acrylates is challenging due to intrinsic side reactions including backbiting reactions of propagating enolate anions and aggregation of active chain ends. In this study, the controlled synthesis of poly(1-adamatyl acrylate) (PAdA) was performed successfully for the first time via living anionic polymerization through investigation of the initiation systems of sec-butyllithium/diphenylethylene/lithium chloride (sec-BuLi/DPE/LiCl), diphenylmethylpotassium/diethylzinc (DPMK/Et 2Zn), and sodium naphthalenide/dipenylethylene/diethylzinc (Na-Naph/DPE/Et2Zn) in tetrahydrofuran at -78 °C using custom glass-blowing and high-vacuum techniques. PAdA synthesized via anionic polymerization using DPMK with a large excess (more than 40-fold to DPMK) of Et 2Zn as the ligand exhibited predicted molecular weightsmore » from 4.3 to 71.8 kg/mol and polydispersity indices of around 1.10. In addition, the produced PAdAs exhibit a low level of isotactic content (mm triads of 2.1%). The block copolymers of AdA and methyl methacrylate (MMA) were obtained by sequential anionic polymerization, and the distinct living property of PAdA over other acrylates was demonstrated based on the observation that the resulting PAdA-b-PMMA block copolymers were formed with no residual PAdA homopolymer. The PAdA homopolymers exhibit a very high glass transition temperature (133 °C) and outstanding thermal stability (T d: 376 °C) as compared to other acrylic polymers such as poly(tert-butyl acrylate) and poly(methyl acrylate). These merits make PAdA a promising candidate for acrylic-based thermoplastic elastomers with high upper service temperature and enhanced mechanical strength.« less

Rheology of acrylic denture-base polymers.

PubMed

Mutlu, G; Huggett, R; Harrison, A; Goodwin, J W; Hughes, R W

1990-10-01

The aim of this study was to investigate the changing rheological behavior of a denture-base polymer from mixing to setting. In addition, monomer evaporation and exothermic behavior of the mix were evaluated. The results show that the material behaves as a pseudoplastic fluid. It is shown that the viscosity increases at different rates with respect to lapsed time, and increases with higher temperature. Also, it is shown that polymerization and monomer evaporation both play a part in dough formation.

Hysteresis-free and submillisecond-response polymer network liquid crystal.

PubMed

Lee, Yun-Han; Gou, Fangwang; Peng, Fenglin; Wu, Shin-Tson

2016-06-27

We demonstrate a polymer network liquid crystal (PNLC) with negligible hysteresis while keeping submillisecond response time. By doping about 1% dodecyl acrylate (C12A) into the liquid crystal/monomer precursor, both hysteresis and residual birefringence are almost completely eliminated. The operating voltage and scattering properties remain nearly intact, but the tradeoff is enhanced double relaxation. This hysteresis-free PNLC should find applications in spatial light modulators, laser beam control, and optical communications in infrared region.

Release of chemical permeation enhancers from drug-in-adhesive transdermal patches.

PubMed

Qvist, Michael H; Hoeck, Ulla; Kreilgaard, Bo; Madsen, Flemming; Frokjaer, Sven

2002-01-14

There is only limited knowledge of how chemical permeation enhancers release from transdermal drug delivery systems of the drug-in-adhesive type. In this study, the release of eight commonly known enhancers from eight types of polymer adhesives was evaluated using Franz diffusion cells. It was shown that all the enhancers released completely from the adhesives and followed a square root of time kinetic (Higuchi law). Using a statistical analysis it was shown that the release rate was more dependent on the type of enhancer than on the type of polymers. The mean release rates were in the range from 2.2 to 11.1%/ radical t for the slowest and fastest releasing enhancers, which correspond to a 50% release within 500 and 20 min, respectively. Furthermore, the release rates were inversely proportional to the cube root of the molal volumes of the enhancers and to their logarithmic partition coefficients between the polymer adhesive and the receptor fluid. It was found that the observed release rates were probably due to a high diffusion coefficient of the enhancers rather than due to an inhomogeneous embedment of the enhancers in the adhesives. The type of adhesive showed minor influence on the release rate, especially among the acrylic polymers no difference was seen. However, compared to the acrylic adhesives, the polyisobutylene adhesive showed slower release rates, while the silicone adhesive showed slightly faster release rates.

Side-Chain Liquid Crystalline Poly(meth)acrylates with Bent-Core Mesogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen,X.; Tenneti, K.; Li, C.

2007-01-01

We report the design, synthesis, and characterization of side-chain liquid crystalline (LC) poly(meth)acrylates with end-on bent-core liquid crystalline (BCLC) mesogens. Both conventional free radical polymerization and atom transfer radical polymerization have been used to synthesize these liquid crystalline polymers (LCP). The resulting polymers exhibit thermotropic LC behavior. Differential scanning calorimetry, thermopolarized light microscopy, wide-angle X-ray diffraction, and small-angle X-ray scattering were used to characterize the LC structure of both monomers and polymers. The electro-optic (EO) measurement was carried out by applying a triangular wave and measuring the LC EO response. SmCP (Smectic C indicates the LC molecules are tilted withmore » respect to the layer normal; P denotes polar ordering) phases were observed for both monomers and polymers. In LC monomers, typical antiferroelectric switching was observed. In the ground state, SmCP{sub A} (A denotes antiferroelectric) was observed which switched to SmCP{sub F} (F denotes ferroelectric) upon applying an electric field. In the corresponding LCP, a unique bilayer structure was observed, which is different from the reported BCLC bilayer SmCG (G denotes generated) phase. Most of the LCPs did not switch upon applying electric field while weak AF switching was observed in a low molecular weight poly{l_brace}3'-[4-(4-n-dodecyloxybenzoyloxy)benzoyloxy]-4-(12-acryloyloxydodecyloxy)benzoyloxybiphenyl{r_brace} sample.« less

Acrylate-endcapped polymer precursors: effect of chemical composition on the healing efficiency of active concrete cracks

NASA Astrophysics Data System (ADS)

Araújo, Maria; Van Tittelboom, Kim; Dubruel, Peter; Van Vlierberghe, Sandra; De Belie, Nele

2017-05-01

The repair of cracks in concrete is an unavoidable practice since these cracks endanger the durability of the structure. Inspired by nature, the self-healing concept has been widely investigated in concrete as a promising solution to solve the limitations of manual repair. This self-healing functionality may be realized by the incorporation of encapsulated healing agents in concrete. Depending on the nature of the cracks, different healing agents can be used. For structures subjected to repeated loads, elastic materials should be considered to cope with the crack opening and closing movement. In this study, various acrylate-endcapped polymer precursors were investigated for their suitability to heal active cracks. The strain capacity of the polymers was assessed by means of visual observation together with water flow tests after widening of the healed cracks in a stepwise manner. A strain of at least 50% could be sustained by epoxy- and siloxane-based healing agents. For polyester- and urethane/poly(propylene glycol)-based precursors, failure occurred at 50% elongation due to detachment of the polymer from the crack walls. However, for urethane/poly(propylene glycol)-based healing agent, debonding was limited to some local spots. The resistance of the polymerized healing agents against degradation in the strong alkaline environment characteristic for concrete has also been evaluated, with the urethane/poly(propylene glycol)-based precursor showing the best performance to withstand degradation.

Variables that affect the mechanism of drug release from osmotic pumps coated with acrylate/methacrylate copolymer latexes.

PubMed

Jensen, J L; Appel, L E; Clair, J H; Zentner, G M

1995-05-01

The feasibility of using modified Eudragit acrylic latexes as microporous coatings for osmotic devices was investigated. Potassium chloride tablets were coated with mixtures of Eudragit RS30D and RL30D acrylic latexes that also contained a plasticizer (triethyl citrate or acetyl tributyl citrate) and a pore-forming agent (urea). A 2(5-1) fractional factorial experimental design was employed to determine the effect of five formulation variables (RS30D:RL30D polymer ratio plasticizer type, plasticizer level, urea level, and cure) on the in vitro release rate of KCl in deionized water (di water), lag time, and coat burst strength. The RS30D:RL30D polymer ratio had the greatest effect on the release rate, and both lag time and burst strength were most affected by the urea level. Statistical optimization was performed, and a coat formulation with predicted desirable in vitro performance was prepared and tested. The in vitro release rate (di water), lag time, and coat burst strength agreed well with the prediction. Dissolutions were also performed in phosphate buffered saline (PBS; pH 7.4); several formulations released markedly slower in PBS than in di water. This discrepancy was dependent on the type of plasticizer and the amount of pore former. Only those coat formulations containing acetyl tributyl citrate as the plasticizer and a 100% urea [(g urea/g polymer solids) x 100] level exhibited similar release rates in di water and PBS. The mechanism of release from these devices was primarily osmotic, whereas the release from devices coated with a formulation containing triethyl citrate and 50% urea was not dependent on the osmotic pressure difference. Devices with an osmotic release mechanism behaved similarly in vivo and in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo evaluation of folate decorated cross-linked micelles for the delivery of platinum anticancer drugs.

PubMed

Eliezar, Jeaniffer; Scarano, Wei; Boase, Nathan R B; Thurecht, Kristofer J; Stenzel, Martina H

2015-02-09

The biodistribution of micelles with and without folic acid targeting ligands were studied using a block copolymer consisting of acrylic acid (AA) and polyethylene glycol methyl ether acrylate (PEGMEA) blocks. The polymers were prepared using RAFT polymerization in the presence of a folic acid functionalized RAFT agent. Oxoplatin was conjugated onto the acrylic acid block to form amphiphilic polymers which, when diluted in water, formed stable micelles. In order to probe the in vivo stability, a selection of micelles were cross-linked using 1,8-diamino octane. The sizes of the micelles used in this study range between 75 and 200 nm, with both spherical and worm-like conformation. The effects of cross-linking, folate conjugation and different conformation on the biodistribution were studied in female nude mice (BALB/c) following intravenous injection into the tail vein. Using optical imaging to monitor the fluorophore-labeled polymer, the in vivo biodistribution of the micelles was monitored over a 48 h time-course after which the organs were removed and evaluated ex vivo. These experiments showed that both cross-linking and conjugation with folic acid led to increased fluorescence intensities in the organs, especially in the liver and kidneys, while micelles that are not conjugated with folate and not cross-linked are cleared rapidly from the body. Higher accumulation in the spleen, liver, and kidneys was also observed for micelles with worm-like shapes compared to the spherical micelles. While the various factors of cross-linking, micelle shape, and conjugation with folic acid all contribute separately to prolong the circulation time of the micelle, optimization of these parameters for drug delivery devices could potentially overcome adverse effects such as liver and kidney toxicity.

Adsorption of Copper Ion using Acrylic Acid-g-Polyaniline in Aqueous Solution

NASA Astrophysics Data System (ADS)

Kamarudin, Sabariah; Mohammad, Masita

2018-04-01

A conductive polymer, polyaniline (PANI) has unique electrical behaviour, stable in the environment, easy synthesis and have wide application in various fields. Modification of PANI in order to improve its adsorption capacity has been done. In this study, the polyaniline-grafted acrylic acid has been prepared and followed by adsorption of copper ion in aqueous solution. Acrylic acid, PANI and acrylic acid-g-polyaniline (Aag-PANI) were characterized by FTIR and SEM to determine its characteristic. The adsorption capacity was investigated to study the removal capacity of Cu ion from aqueous solution. Two parameters were selected which are pH (2, 4 and 6) and initial metal ion concentration (50 mg/L, 100 mg/L and 200 mg/L). The maximum adsorption capacity for PANI and Aag-PANI are 1.7 mg/g and 64.6 mg/g, respectively, at an initial concentration of 100 mg/L. The Langmuir adsorption isotherm model and Freundlich adsorption isotherm model have been used and showed that it is heterolayer adsorption by follows the Freundlich isotherm model.

Sulfonated macro-RAFT agents for the surfactant-free synthesis of cerium oxide-based hybrid latexes.

PubMed

Garnier, Jérôme; Warnant, Jérôme; Lacroix-Desmazes, Patrick; Dufils, Pierre-Emmanuel; Vinas, Jérôme; van Herk, Alex

2013-10-01

Three types of amphiphatic macro-RAFT agents were employed as compatibilizers to promote the polymerization reaction at the surface of nanoceria for the synthesis of CeO2-based hybrid latexes. Macro-RAFT copolymers and terpolymers were first synthesized employing various combinations of butyl acrylate as a hydrophobic monomer and acrylic acid (AA) and/or 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as hydrophilic monomers. After characterizing the adsorption of these macro-RAFT agents at the cerium oxide surface by UV-visible spectrometry, emulsion copolymerization reactions of styrene and methyl acrylate were then carried out in the presence of the surface-modified nanoceria. Dynamic Light Scattering and cryo-Transmission Electron Microscopy were employed to confirm the hybrid structure of the final CeO2/polymer latexes, and proved that the presence of acrylic acid units in amphiphatic macro-RAFT agents enabled an efficient formation of hybrid structures, while the presence of AMPS units, when combined with AA units, resulted in a better distribution of cerium oxide nanoclusters between latex particles. Copyright © 2013 Elsevier Inc. All rights reserved.

Inhibition of Staphylococcus epidermidis biofilms using polymerizable vancomycin derivatives.

PubMed

Lawson, McKinley C; Hoth, Kevin C; Deforest, Cole A; Bowman, Christopher N; Anseth, Kristi S

2010-08-01

Biofilm formation on indwelling medical devices is a ubiquitous problem causing considerable patient morbidity and mortality. In orthopaedic surgery, this problem is exacerbated by the large number and variety of material types that are implanted. Metallic hardware in conjunction with polymethylmethacrylate (PMMA) bone cement is commonly used. We asked whether polymerizable derivatives of vancomycin might be useful to (1) surface modify Ti-6Al-4V alloy and to surface/bulk modify PMMA bone cement to prevent Staphylococcus epidermidis biofilm formation and (2) whether the process altered the compressive modulus, yield strength, resilience, and/or fracture strength of cement copolymers. A Ti-6Al-4V alloy was silanized with methacryloxypropyltrimethoxysilane in preparation for subsequent polymer attachment. Surfaces were then coated with polymers formed from PEG(375)-acrylate or a vancomycin-PEG(3400)-PEG(375)-acrylate copolymer. PMMA was loaded with various species, including vancomycin and several polymerizable vancomycin derivatives. To assess antibiofilm properties of these materials, initial bacterial adherence to coated Ti-6Al-4V was determined by scanning electron microscopy (SEM). Biofilm dry mass was determined on PMMA coupons; the compressive mechanical properties were also determined. SEM showed the vancomycin-PEG(3400)-acrylate-type surface reduced adherent bacteria numbers by approximately fourfold when compared with PEG(375)-acrylate alone. Vancomycin-loading reduced all mechanical properties tested; in contrast, loading a vancomycin-acrylamide derivative restored these deficits but demonstrated no antibiofilm properties. A polymerizable, PEGylated vancomycin derivative reduced biofilm attachment but resulted in inferior cement mechanical properties. The approaches presented here may offer new strategies for developing biofilm-resistant orthopaedic materials. Specifically, polymerizable derivatives of traditional antibiotics may allow for direct polymerization into existing materials such as PMMA bone cement while minimizing mechanical property compromise. Questions remain regarding ideal monomer structure(s) that confer biologic and mechanical benefits.

Frit inlet field-flow fractionation techniques for the characterization of polyion complex self-assemblies.

PubMed

Till, Ugo; Gaucher, Mireille; Amouroux, Baptiste; Gineste, Stéphane; Lonetti, Barbara; Marty, Jean-Daniel; Mingotaud, Christophe; Bria, Carmen R M; Williams, S Kim Ratanathanawongs; Violleau, Frédéric; Mingotaud, Anne-Françoise

2017-01-20

Polymer self-assemblies joining oppositely charged chains, known as polyion complexes (PICs), have been formed using poly(ethyleneoxide - b - acrylic acid)/poly(l-lysine), poly(ethyleneoxide-b-acrylic acid)/dendrigraft poly(l-lysine) and poly[(3-acrylamidopropyl) trimethylammonium chloride - b - N - isopropyl acrylamide]/poly(acrylic acid). The self-assemblies have been first characterized in batch by Dynamic Light Scattering. In a second step, their analysis by Flow Field-Flow Fractionation techniques (FlFFF) was examined. They were shown to be very sensitive to shearing, especially during the focus step of the fractionation, and this led to an incompatibility with asymmetrical FlFFF. On the other hand, Frit Inlet FlFFF proved to be very efficient to observe them, either in its symmetrical (FI-FlFFF) or asymmetrical version (FI-AsFlFFF). Conditions of elution were found to optimize the sample recovery in pure water. Spherical self-assemblies were detected, with a size range between 70-400nm depending on the polymers. Compared to batch DLS, FI-AsFlFFF clearly showed the presence of several populations in some cases. The influence of salt on poly(ethyleneoxide-b-acrylic acid) (PEO-PAA) 6000-3000/dendrigraft poly(l-lysine) (DGL 3) was also assessed in parallel in batch DLS and FI-AsFlFFF. Batch DLS revealed a first process of swelling of the self-assembly for low concentrations up to 0.8M followed by the dissociation. FI-AsFlFFF furthermore indicated a possible ejection of DGL3 from the PIC assembly for concentrations as low as 0.2M, which could not be observed in batch DLS. Copyright © 2016 Elsevier B.V. All rights reserved.

Long term flight electrodes

NASA Technical Reports Server (NTRS)

Mosier, B.

1975-01-01

The reproducibility, stability, and methods of preparation for the various types and forms of biomedical electrodes are discussed. A critical and selective compilation of information on biological and/or physiological electrodes is presented. A discussion of plant hydrocolloids, clays, hydrophyllic colloids, synthetic waxes, and acrylic polymers is included.

Novel chronotherapeutic rectal aminophylline delivery system for therapy of asthma.

PubMed

Shiohira, Hideo; Fujii, Makiko; Koizumi, Naoya; Kondoh, Masuo; Watanabe, Yoshiteru

2009-09-08

The aim of this study was to develop a new chronotherapeutic pharmaceutical preparation as a sustained-release suppository for prevention and therapeutic use against bronchial asthma in the early morning. Sustained-release hollow-type (SR-HT) suppositories using sodium alginate (Alg-Na), sodium polyacrylate (PANa) or polyacrylate-PANa co-polymer (PA-PANa) as gelling polymers (gel agent) were prepared and pharmaceutical characteristics of these suppositories were investigated. Type A SR-HT suppositories comprised a suppository shell prepared with oleaginous base and containing aminophylline only or aminophylline with Alg-Na or PANa in the cavity (hollow space). Type B SR-HT suppositories comprised a suppository shell prepared with oleaginous base and gel agent (30%), with aminophylline in the hollow space. In drug-release studies, the acrylate polymer-containing suppositories showed linearity of delayed release rate, providing significantly decreased the highest concentration of theophylline in plasma (C(max)) and delayed the time required to reach C(max) (t(max)) and the mean residence time (MRT) after rectal administrated in rabbits. In particular, suppositories containing PA-PANa maintained significantly higher theophylline concentrations than control suppositories at 12h after rectal administration. Furthermore, histopathological examination indicated that these suppositories using acrylate polymers did not result in rectal lesions. The SR-HT suppository, particularly using PA-PANa as a gel agent, may thus be useful against nocturnal symptoms of asthma. In this study, we confirmed new formulation of sustained-release suppository for chronotherapy of theophylline using oily base material in combination with polymer such as PA-PANa. The hollow-type suppository containing oleaginous base and hydrophilic polymer in the shell could be useful device for rectal administration of various drugs with prolongation of plasma concentration.

The actuation of a biomimetic poly(vinyl alcohol)poly(acrylic acid) gel.

PubMed

Marra, S P; Ramesh, K T; Douglas, A S

2002-02-15

Active polymer gels expand and contract in response to certain environmental stimuli, such as the application of an electric field or a change in the pH level of the surroundings. This ability to achieve large, reversible deformations with no external mechanical loading has generated much interest in the use of these gels as biomimetic actuators and "artificial muscles". In previous work, a thermodynamically consistent finite-elastic constitutive model has been developed to describe the mechanical and actuation behaviours of active polymer gels. The mechanical properties were characterized by a free-energy function, and the model uses an evolving internal variable to describe the actuation state. In this work, an evolution law for the internal variable is determined from free actuation experiments on a poly(vinyl alcohol)poly(acrylic acid) (PVAPAA) gel. The complete finite-elastic/evolution law constitutive model is then used to predict the response of the PVA-PAA gel to isotonic and isometric loading and actuation. The model is shown to give relatively good agreement with experimental results.

The graft polymers from different species of lignin and acrylic acid: synthesis and mechanism study.

PubMed

Ye, De zhan; Jiang, Li; Ma, Chao; Zhang, Ming-hua; Zhang, Xi

2014-02-01

The influence of lignin species on the grafting mechanism of lignosulfonate (from eucalyptus and pine, recorded as HLS and SLS, respectively) with acrylic acid (AA) was investigated. The graft polymers were confirmed by the absorption of carbonyl groups in the FTIR spectra. The decreasing phenolic group's content (Ph-OH) is not only due to its participation as grafting site but also to the negative effect of initiator. In the initial period (0-60 min), HLS and SLS both accelerate the polymerization of AA. Additionally, Ph-OH group's content is proportional to product yield (Y%), monomer conversion (C%) and grafting efficiency (GE%), strongly indicating that it acts as active center. Nevertheless, compared with HLS, Y% and C% in SLS grafting system are lower though it has higher Ph-OH group's content, which is due to the quinonoid structure formed by the self-conjugated of phenoxy radical in Guaiacyl unit. Finally, the lignosulfonate grafting mechanism was proposed. Copyright © 2013 Elsevier B.V. All rights reserved.

Sugarcane bagasse derivative-based superabsorbent containing phosphate rock with water-fertilizer integration.

PubMed

Zhong, Kang; Zheng, Xi-Liang; Mao, Xiao-Yun; Lin, Zuan-Tao; Jiang, Gang-Biao

2012-10-01

To improve the water-fertilizer utilization ratio and mitigate the environmental contamination, an eco-friendly superabsorbent polymer (SPA), modified sugarcane bagasse/poly (acrylic acid) embedding phosphate rock (MSB/PAA/PHR), was prepared. Ammonia, phosphate rock (PHR) and KOH were admixed in the presence of acrylic acid to provide nitrogen (N), phosphorus (P) and potassium (K) nutrients, respectively. Impacts on water absorption capacity of the superabsorbent polymer (SAP) were investigated. The maximum swelling capacity in distilled water and 0.9 wt.% (weight percent) NaCl solution reached 414 gg(-1) and 55 gg(-1) (water/prepared SAP), respectively. The available NPK contents of the combination system were 15.13 mgg(-1), 6.93 mgg(-1) and 52.05 mgg(-1), respectively. Moreover, the release behaviors of NPK in the MSB/PAA/PHR were also studied. The results showed that the MSB/PAA/PHR has outstanding sustained-release plant nutrients property. Copyright © 2012 Elsevier Ltd. All rights reserved.

Strategic design and fabrication of acrylic shape memory polymers

NASA Astrophysics Data System (ADS)

Park, Ju Hyuk; Kim, Hansu; Ryoun Youn, Jae; Song, Young Seok

2017-08-01

Modulation of thermomechanics nature is a critical issue for an optimized use of shape memory polymers (SMPs). In this study, a strategic approach was proposed to control the transition temperature of SMPs. Free radical vinyl polymerization was employed for tailoring and preparing acrylic SMPs. Transition temperatures of the shape memory tri-copolymers were tuned by changing the composition of monomers. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses were carried out to evaluate the chemical structures and compositions of the synthesized SMPs. The thermomechanical properties and shape memory performance of the SMPs were also examined by performing dynamic mechanical thermal analysis. Numerical simulation based on a finite element method provided consistent results with experimental cyclic shape memory tests of the specimens. Transient shape recovery tests were conducted and optical transparence of the samples was identified. We envision that the materials proposed in this study can help develop a new type of shape-memory devices in biomedical and aerospace engineering applications.

Neutral glycans from sandfish skin can reduce friction of polymers

PubMed Central

Vihar, Boštjan; Hanisch, Franz Georg; Baumgartner, Werner

2016-01-01

The lizard Scincus scincus, also known as sandfish, can move through aeolian desert sand in a swimming-like manner. A prerequisite for this ability is a special integument, i.e. scales with a very low friction for sand and a high abrasion resistance. Glycans in the scales are causally related to the low friction. Here, we analysed the glycans and found that neutral glycans with five to nine mannose residues are important. If these glycans were covalently bound to acrylic polymers like poly(methyl methacrylate) or acrylic car coatings at a density of approximately one molecule per 4 nm², friction for and adhesion of sand particles could be reduced to levels close to those observed with sandfish scales. This was also found true, if the glycans were isolated from sources other than sandfish scales like plants such as almonds or mistletoe. We speculate that these neutral glycans act as low density spacers separating sand particles from the dense scales thereby reducing van der Waals forces. PMID:27030038

Determination of diffusion coefficients of biocides on their passage through organic resin-based renders.

PubMed

Styszko, Katarzyna; Kupiec, Krzysztof

2016-10-01

In this study the diffusion coefficients of isoproturon, diuron and cybutryn in acrylate and silicone resin-based renders were determined. The diffusion coefficients were determined using measuring concentrations of biocides in the liquid phase after being in contact with renders for specific time intervals. The mathematical solution of the transient diffusion equation for an infinite plate contacted on one side with a limited volume of water was used to calculate the diffusion coefficient. The diffusion coefficients through the acrylate render were 8.10·10(-9) m(2) s(-1) for isoproturon, 1.96·10(-9) m(2) s(-1) for diuron and 1.53·10(-9) m(2) s(-1) for cybutryn. The results for the silicone render were lower by one order of magnitude. The compounds with a high diffusion coefficient for one polymer had likewise high values for the other polymer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Healable Antifouling Films Composed of Partially Hydrolyzed Poly(2-ethyl-2-oxazoline) and Poly(acrylic acid).

PubMed

Li, Yixuan; Pan, Tiezheng; Ma, Benhua; Liu, Junqiu; Sun, Junqi

2017-04-26

Antifouling polymeric films can prevent undesirable adhesion of bacteria but are prone to accidental scratches, leading to a loss of their antifouling functions. To solve this problem, we report the fabrication of healable antifouling polymeric films by layer-by-layer assembly of partially hydrolyzed poly(2-ethyl-2-oxazoline) (PEtOx-EI-7%) and poly(acrylic acid) (PAA) based on hydrogen-bonding interaction as the driving force. The thermally cross-linked (PAA/PEtOx-EI-7%)*100 films show strong resistance to adhesion of both Gram-negative Escherichia coli and Gram-positive Bacillus subtilis bacteria due to the high surface and bulk concentration of the antifouling polymer PEtOx-EI-7%. Meanwhile, the dynamic nature of the hydrogen-bonding interactions and the high mobility of the polymers in the presence of water enable repeated healing of cuts of several tens of micrometers wide in cross-linked (PAA/PEtOx-EI-7%)*100 films to fully restore their antifouling function.

Duty cycle dependent chemical structure and wettability of RF pulsed plasma copolymers of acrylic acid and octafluorocyclobutane

NASA Astrophysics Data System (ADS)

Muzammil, I.; Li, Y. P.; Li, X. Y.; Lei, M. K.

2018-04-01

Octafluorocyclobutane and acrylic acid (C4F8-co-AA) plasma copolymer coatings are deposited using a pulsed wave (PW) radio frequency (RF) plasma on low density polyethylene (LDPE). The influence of duty cycle in pulsed process with the monomer feed rate on the surface chemistry and wettability of C4F8-co-AA plasma polymer coatings is studied. The concentration of the carboxylic acid (hydrophilic) groups increase, and that of fluorocarbon (hydrophobic) groups decrease by lowering the duty cycle. The combined effect of surface chemistry and surface morphology of the RF pulsed plasma copolymer coatings causes tunable surface wettability and surface adhesion. The gradual emergence of hydrophilic contents leads to surface heterogeneity by lowering duty cycle causing an increased surface adhesion in hydrophobic coatings. The C4F8-co-AA plasma polymer coatings on the nanotextured surfaces are tuned from repulsive superhydrophobicity to adhesive superhydrophobicity, and further to superhydrophilicity by adjusting the duty cycles with the monomer feed rates.

Latex imaging by environmental STEM: application to the study of the surfactant outcome in hybrid alkyd/acrylate systems.

PubMed

Faucheu, Jenny; Chazeau, Laurent; Gauthier, Catherine; Cavaillé, Jean-Yves; Goikoetxea, Monika; Minari, Roque; Asua, José M

2009-09-01

Among other uses, latexes are a successful alternative to solvent-borne binders for coatings. Efforts are made to produce hybrid nanostructured latexes containing an acrylic phase and an alkyd phase. However, after the film-forming process, the surfactant used to stabilize these latexes remains in the film, and its location can have a drastic effect on the application properties. Among the processing parameters, the alkyd hydrophobicity can strongly influence this location. This article aims at the imaging of these surfactant molecules in two hybrid latexes with different hydrophobicity level of the alkyd resin. A first part of this paper is dedicated to the understanding of the contrast provided by the surfactant in environmental STEM imaging of latexes. Then, the influence of surfactant-polymer affinity on the surfactant location after film-forming of those hybrid alkyd/acrylate latexes is studied by this technique. It is shown that in the hybrid latex with an alkyd shell (obtained with the most hydrophilic resin), the surfactant molecules tend to remain buried in the alkyd phase. Conversely, in the hybrid latex with an acrylate shell (in the case of the most hydrophobic resin), the surfactant molecules tend to gather into islands like in pure acrylate latex films.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carranza, Arturo; Gewin, Mariah; Pojman, John A., E-mail: japojman@lsu.edu

In this study, we present an inexpensive and practical method that allows the monitoring and visualization of front polymerization, propagation, and dynamics. Commercially available europium-doped aluminum oxide powders were combined with video imaging to visualize free-radical propagating polymer fronts. In order to demonstrate the applicability of this method, frontal copolymerization reactions of propoxylated glycerin triacrylate (EB53), pentaerythritol triacrylate (PETA), and pentaerythritol tetra-acrylate (PETEA) with 1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (Luperox 231®) as an initiator were studied and compared to the results obtained by IR imaging. Systems exhibiting higher filler loading, higher EB53 content, and less acrylated monomers showed a marked decrease in front velocity,more » while those with more acrylated monomers and higher crosslinking density showed a marked increase in front velocity. Finally, in order to show the potential of the imaging technique, we studied fronts propagating in planar and spherical geometries.« less

Studies of organic paint binders by NMR spectroscopy

NASA Astrophysics Data System (ADS)

Spyros, A.; Anglos, D.

2006-06-01

Nuclear magnetic resonance spectroscopy is applied to the study of aged binding media used in paintings, namely linseed oil, egg tempera and an acrylic medium. High resolution 1D and 2D NMR experiments establish the state of hydrolysis and oxidation of the linseed and egg tempera binders after five years of aging, by determining several markers sensitive to the hydrolytic and oxidative processes of the binder lipid fraction. The composition of the acrylic binder co-polymer is determined by 2D NMR spectroscopy, while the identification of a surfactant, poly(ethylene glycol), found in greater amounts in aged acrylic medium, is reported. The non-destructive nature of the proposed analytical NMR methodology, and minimization of the amount of binder material needed through the use of sophisticated cryoprobes and hyphenated LC-NMR techniques, make NMR attractive for the arts analyst, in view of its rapid nature and experimental simplicity.

Peel/seal properties of poly(ethylene methyl acrylate)/polybutene-1 blend films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohammdi, Seyedeh Raziyeh; Ajji, Abdellah; Tabatabaei, Seyed H.

Nowadays, the possibility to easy open a food package is of great interest both from the consumer and food producers’ perspective. In this study, the peel/seal properties of poly (ethylene methyl acrylate) (EMA)/polybutene-1 (PB-1) blend films were investigated. Three blends of EMA/PB-1 with different methyl acrylate (MA) content were prepared using cast extrusion process. Differential Scanning Calorimetry (DSC) was used to investigate the thermal behavior as well as the crystalinity of the blends. The effect of polymer matrix on the crystalline structure of PB-1 was studied using Wide Angle X-ray Diffraction (WAXD) and DSC. T-peel tests were carried out onmore » the heat sealed films at various seal temperatures. The effect of MA content and heat seal temperature on peel/seal properties (i.e. peel initiation temperature, temperature window of sealability and peel strength) of the films were studied.« less

Influence of Surface Properties on the Adhesion of Staphylococcus epidermidis to Acrylic and Silicone

PubMed Central

Sousa, Cláudia; Teixeira, Pilar; Oliveira, Rosário

2009-01-01

The aim of the present study was to compare the ability of eight Staphylococcus epidermidis strains to adhere to acrylic and silicone, two polymers normally used in medical devices manufacture. Furthermore, it was tried to correlate that with the surface properties of substrata and cells. Therefore, hydrophobicity and surface tension components were calculated through contact angle measurements. Surface roughness of substrata was also assessed by atomic force microscopy (AFM). No relationship was found between microbial surface hydrophobicity and adhesion capability. Nevertheless, Staphylococcus epidermidis IE214 showed very unique adhesion behaviour, with cells highly aggregated between them, which is a consequence of their specific surface features. All strains, determined as being hydrophilic, adhered at a higher extent to silicone than to acrylic, most likely due to its more hydrophobic character and higher roughness. This demonstrates the importance of biomaterial surface characteristics for bacterial adhesion. PMID:20126579

Characteristics and mechanisms of acrylate polymer damage to maize seedlings.

PubMed

Chen, Xian; Mao, Xiaoyun; Lu, Qin; Liao, Zongwen; He, Zhenli

2016-07-01

Superabsorbent acrylate polymers (SAPs) have been widely used to maintain soil moisture in agricultural management, but they may cause damage to plants, and the mechanisms are not well understood. In this study, seed germination, soil pot culture, hydroponic experiments, and SAPs degradation were conducted to investigate damage characteristics and mechanisms associated with SAPs application. The Results showed that SAPs inhibited maize growth and altered root morphology (irregular and loose arrangement of cells and breakage of cortex parenchyma), and the inhibitory effects were enhanced at higher SAPs rates. After 1h SAP hydrogels treatment, root malondialdehyde (MDA) content was significantly increased, while superoxide dismutase (SOD) and catalase (CAT) content were significantly decreased. Hydroponics experiment indicated that root and shoot growth was inhibited at 2.5mgL(-1) acrylic acid (AA), and the inhibition was enhanced with increasing AA rates. This effect was exacerbated by the presence of Na(+) at a high concentration in the hydrogels. Release and degradation of AA were enhanced at higher soil moisture levels. A complete degradation of AA occurred between 15 and 20 days after incubation (DAI), but it took longer for Na(+) concentration to decrease to a safe level. These results indicate that high concentration of both AA and Na(+) present in the SAPs inhibits plant growth. The finding of this study may provide a guideline for appropriate application of SAPs in agriculture. Copyright © 2016 Elsevier Inc. All rights reserved.

Purifying Water by Imbibition

NASA Technical Reports Server (NTRS)

Lawton, E. A.

1986-01-01

Concept for purifying water uses absorbent material to remove organic substances. Entire bulk of material employed, not just surface. Proposed purification process uses inexpensive equipment and low energy. Material is methyl acrylate polymer. Material cheap and regenerated by rinsing with methanol or by allowing absorbed compounds to evaporate from it.

40 CFR 799.5025 - Testing consent orders for mixtures without Chemical Abstracts Service Registry Numbers.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Polytetrafluoroethylene, DCN No. 63040000018B ......do Do. Fluorotelomer-based composite substance: (1) For Paper containing three of the following chemical substances as specified in the ECA: (i) Perfluoroalkylethyl...) Perfluoroalkyl acrylate copolymer, ACC 158022 ......do Do. (iii) Perfluoroalkyl methacrylate polymer, EPA...

HYBRID MINIEMULSION POLYMERIZATION OF ACRYLIC/ALKYD SYSTEMS AND CHARACTERIZATION OF THE RESULTING POLYMERS. (R825326)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Investigation of test methods, material properties, and processes for solar cell encapsulants. Encapsulation task of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

1977-01-01

During this quarter, flat-plate solar collector systems were considered and six basic construction elements were identified: outer coatings, superstrates, pottants, substrates, undercoats, and adhesives. Materials surveys were then initiated to discover either generic classes or/and specific products to function as each construction element. Cost data included in the surveys permit ready evaluation of each material. Silicones, fluorocarbons, glass, and acrylic polymers have the highest inherent weatherability of materials studied to date. Only acrylics, however, combine low costs, environmental resistance, and potential processability. This class will receive particular emphasis.

Large-strain, rigid-to-rigid deformation of bistable electroactive polymers

NASA Astrophysics Data System (ADS)

Yu, Zhibin; Yuan, Wei; Brochu, Paul; Chen, Bin; Liu, Zhitian; Pei, Qibing

2009-11-01

Thermoplastic poly(tert-butyl acrylate) (PTBA) is reported as an electroactive polymer that is rigid at ambient conditions and turns into a dielectric elastomer above a transition temperature. In the rubbery state, a PTBA thin film can be electrically actuated to strains up to 335% in area expansion. The calculated actuation pressure is 3.2 MPa. The actuation is made bistable by cooling to below glass transition temperature. The PTBA represents the bistable electroactive polymer (BSEP) that can be actuated to various largely strained, rigid shapes. The application of the BSEP for refreshable Braille display, an active tactile display, is also demonstrated.

Preparing high-density polymer brushes by mechanically assisted polymer assembly (MAPA)

NASA Astrophysics Data System (ADS)

Wu, Tao; Efimenko, Kirill; Genzer, Jan

2001-03-01

We introduce a novel method of modifying the surface properties of materials. This technique, called MAPA (="mechanically assisted polymer assembly"), is based on: 1) chemically attaching polymerization initiators to the surface of an elastomeric network that has been previously stretched by a certain length, Δx, and 2) growing end-anchored macromolecules using surface initiated ("grafting from") atom transfer living radical polymerization. After the polymerization, the strain is removed from the substrate, which returns to its original size causing the grafted macromolecules to stretch away from the substrate and form a dense polymer brush. We demonstrate the feasibility of the MAPA method by preparing high-density polymer brushes of poly(acryl amide), PAAm. We show that, as expected, the grafting density of the PAAm brushes can be increased by increasing Δx. We demonstrate that polymer brushes with extremely high grafting densities can be successfully prepared by MAPA.

[Preparation of Pb2+ imprinted acrylic acid-co-styrene and analysis of its adsorption properties by FAAS].

PubMed

Shawket, Abliz; Abdiryim, Supahun; Wang, Ji-De; Ismayil, Nurulla

2011-06-01

With lead ion template, acrylic acid as functional monomer, potassium persulfate as initiator, strytrene as framework monomer, lead ion imprinted polymers (Pb(II)-IIPs) were prepared using free emulsion polymerization method. The structure and morphology of the polymers were analyzed by UV-spectra, FTIR and scanning electron microscopy. The adsorption/ desorption and selectivity for Pb2+ were investigated by flame atomic absorption spectrometry (FAAS) as the detection means. The results show that compared with non-imprinted polymers(NIPs), the Pb(II)-IIPs had higher specific adsorption properties and selective recognition ability for Pb(II). The relative selectivity coefficient of Pb(II)-IIPs for Pb(II) was 6.25, 6.18, 6.25 and 6.38 in the presence of Cd(II), Cu(II), Mn(II) and Zn(II) interferences, respectively. The absorption rate was the best at the pH of adsorbent solution of 6, Adsorption rate reached 96% during the 2.5 h static adsorption time. Using 3.0 mol x L(-1) HCI as the best desorption solvent to desorb the adsorbents, the desorbtion rate reached 98%. Under the best adsorption conditions, the adsorption capacity of Pb(II)-IIPs for Pb(II) was found to be 40. mg x g(-1).

Mitigation of Biofilm Formation on Corrugated Cardboard Fresh Produce Packaging Surfaces Using a Novel Thiazolidinedione Derivative Integrated in Acrylic Emulsion Polymers

PubMed Central

Brandwein, Michael; Al-Quntar, Abed; Goldberg, Hila; Mosheyev, Gregory; Goffer, Moshe; Marin-Iniesta, Fulgencio; López-Gómez, Antonio; Steinberg, Doron

2016-01-01

Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analog cardboard packaging using high throughput sequencing technology. We further developed an anti-biofilm polymer meant to coat corrugated cardboard surfaces and mediate bacterial biofilm growth on said surfaces. Integration of a novel thiazolidinedione derivative into the acrylic emulsion polymers was assessed using Energy Dispersive X-ray Spectrometry (EDS) analysis and surface topography was visualized and quantified on corrugated cardboard surfaces. Biofilm growth was measured using q-PCR targeting the gene encoding 16s rRNA. Additionally, architectural structure of the biofilm was observed using SEM. The uniform integration of the thiazolidinedione derivative TZD-6 was confirmed, and it was determined via q-PCR to reduce biofilm growth by ~80% on tested surfaces. A novel and effective method for reducing microbial load and preventing contamination on food packaging is thereby proposed. PMID:26909074

Bioinspired Polymeric Photonic Crystals for High Cycling pH-Sensing Performance.

PubMed

Fei, Xiang; Lu, Tao; Ma, Jun; Wang, Wanlin; Zhu, Shenmin; Zhang, Di

2016-10-12

Artificial photonic crystals (PCs) have been extensively studied to improve the sensing performance of poly(acrylic acid) (PAAc), as it can transform the PAAc volume change into optical signal which is easier to read. Nevertheless, these PCs are limited by the monostructure. We herein developed new photonic crystals (PCs) by coating acrylic acid and acrylamide (AAm) via in situ copolymerization onto Papilio paris wings having hierarchical, lamellar structure. Our PCs exhibited high performance of color tunability to environmental pH, as detected by reflectance spectra and visual observation. The introduction of AAm into the system created covalent bonding which robustly bridged the polymer with the wings, leading to an accurate yet broad variation of reflection wavelength to gauge environmental pH. The reflection wavelength can be tailored by the refractive index of the lamellar interspacing due to the swelling/deswelling of the polymer. The mechanism is not only supported by experimenta but proved by finite-difference time-domain simulation. Moreover, It is worth noting that the covalent bonding has provided the PCs-based pH sensor with high cycling performance, implying great potential in practical applications. The simple fabrication process is applicable to the development of a wide variety of stimuli-responsive PCs taking advantage of other polymers.

High Strength Carbide-Based Fibrous Monolith Materials for Solid Rocket Nozzles

DTIC Science & Technology

2008-02-19

individual powders are blended with thermoplastic melt-extrudable polymer binders and plasticizers , using a high shear mixer (Brabender Technologie Inc...Ethylene Ethyl Acrylate, EEA DuPont MFI 1.5 and 20 DPDA 9169 NT Stearic Acid Crompton Hystrene 97 18 NF FG 65 References 1. J. B

A chromatographic analysis of the response of polymeric fire-detection devices to combustion products

NASA Technical Reports Server (NTRS)

Senturia, S. D.

1977-01-01

Polymer responses to a variety of smouldering sources, including cellulose, acrylic, urethane, polyvinyl chloride, and wool were investigated. A suitable trapping system for combustion products was developed and a charge flow transistor was fabricated to monitor the transverse or sheet resistance of a thin film.

Wastewater Collection System Rehabilitation Techniques for Army Installation

DTIC Science & Technology

1988-11-01

eliminate contact with water. For an occasional user, acrylate polymer is the least difficult to use from a toxi - city and handling point of view. Foam...and other materials common in sanitary sewage. It is sus- ceptible to damage from nonpolar materials such as gasoline , oils, organic solvents, etc. The

Holographic recording medium employing a photoconductive layer and a low molecular weight microcrystalline polymeric layer

NASA Technical Reports Server (NTRS)

Gange, Robert Allen (Inventor)

1977-01-01

A holographic recording medium comprising a conductive substrate, a photoconductive layer and an electrically alterable layer of a linear, low molecular weight hydrocarbon polymer has improved fatigue resistance. An acrylic barrier layer can be interposed between the photoconductive and electrically alterable layers.

Entropy driven chain effects on ligation chemistry† †Electronic supplementary information (ESI) available: Synthetic details, applied MHKS parameters, SEC chromatograms of all samples, (HT) NMR data, experimental debonding values, SANS measurements, computational data (energy contributions and geometries in the form of Gaussian archive entries). See DOI: 10.1039/c4sc02908a Click here for additional data file.

PubMed Central

Pahnke, Kai; Brandt, Josef; Gryn'ova, Ganna; Lindner, Peter; Schweins, Ralf; Schmidt, Friedrich Georg

2015-01-01

We report the investigation of fundamental entropic chain effects that enable the tuning of modular ligation chemistry – for example dynamic Diels–Alder (DA) reactions in materials applications – not only classically via the chemistry of the applied reaction sites, but also via the physical and steric properties of the molecules that are being joined. Having a substantial impact on the reaction equilibrium of the reversible ligation chemistry, these effects are important when transferring reactions from small molecule studies to larger or other entropically very dissimilar systems. The effects on the DA equilibrium and thus the temperature dependent degree of debonding (%debond) of different cyclopentadienyl (di-)functional poly(meth-)acrylate backbones (poly(methyl methacrylate), poly(iso-butyl methacrylate), poly(tert-butyl methacrylate), poly(iso-butyl acrylate), poly(n-butyl acrylate), poly(tert-butyl acrylate), poly(methyl acrylate) and poly(isobornyl acrylate)), linked via a difunctional cyanodithioester (CDTE) were examined via high temperature (HT) NMR spectroscopy as well as temperature dependent (TD) SEC measurements. A significant impact of not only chain mass and length with a difference in the degree of debonding of up to 30% for different lengths of macromonomers of the same polymer type but – remarkably – as well the chain stiffness with a difference in bonding degrees of nearly 20% for isomeric poly(butyl acrylates) is found. The results were predicted, reproduced and interpreted via quantum chemical calculations, leading to a better understanding of the underlying entropic principles. PMID:29560194

Surface-modified multifunctional MIP nanoparticles

NASA Astrophysics Data System (ADS)

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

2013-04-01

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors. Electronic supplementary information (ESI) available: Details of the synthesis of eosin O-acrylate monomer and 1H-NMR spectrum of MIP NPs post-derivatised with PEG shell. See DOI: 10.1039/c3nr00354j

Application of an Addition-Fragmentation-Chain Transfer Monomer in Di(meth)acrylate Network Formation to Reduce Polymerization Shrinkage Stress.

PubMed

Shah, Parag K; Stansbury, Jeffrey W; Bowman, Christopher N

2017-08-14

A new addition-fragmentation chain transfer (AFT) capable moiety was incorporated into a dimethacrylate monomer that participated readily in network formation by copolymerizing with multifunctional methacrylates or acrylates. The process of AFT occurred simultaneously with photopolymerization of the AFT monomer (AFM) and other (meth)acrylate monomers leading to polymer stress relaxation via network reconfiguration. At low loading levels of the AFM, a significant reduction in shrinkage stress, especially for acrylate monomers, was observed with nominal effects on conversion. At higher loading levels of the AFM, the photopolymerization reaction kinetics and final double bond conversion were significantly lowered along with a delay in the gel-point conversion. Electron paramagnetic resonance studies during polymerization revealed the presence of a distinct radical species that was present in proportional quantities to the AFM content in the system. The lifetime and the character of the persistent radicals were altered due to the presence of the distinctive radical, in turn affecting the polymerization kinetics. With polymerization conducted at higher irradiance, the differential conversion between the control resin and samples with moderate AFM content was minimal, especially for the methacrylate-based formulations.

Transport of poly(acrylic acid) coated 2-line ferrihydrite nanoparticles in saturated aquifer sediments for environmental remediation

NASA Astrophysics Data System (ADS)

Xiang, Aishuang; Zhou, Sheng; Koel, Bruce E.; Jaffé, Peter R.

2014-04-01

Groundwater remediation using iron oxide and zero-valent iron nanoparticles (NPs) can be effective, but is limited in many applications due to the NP strong retention in groundwater-saturated porous media after injection, the passivation of the porous surface, and the high cost of nanomaterials versus macro scale iron. In this study, we investigated transport of bare and polymer-coated 2-line ferrihydrite NPs (30-300 nm) in saturated aquifer sediments. The influence of poly(acrylic acid) (PAA) polymer coatings was studied on the colloidal stability and transport in sediments packed column tests simulating groundwater flow in saturated sediments. In addition, the influence of calcium cations was investigated by transport measurements using sediments with calcium concentrations in the aqueous phase ranging from 0.5 (typical for most sediments) to 2 mM. Measurements were also made of zeta potential, hydrodynamic diameter, polymer adsorption and desorption properties, and bio-availability of PAA-coated NPs. We found that NP transport through the saturated aquifer sediments was improved by PAA coating and that the transport properties could be tuned by adjusting the polymer concentration. We further discovered that PAA coatings enhanced NP transport, compared to bare NPs, in all calcium-containing experiments tested, however, the presence of calcium always exhibited a negative effect on NP transport. In tests of bioavailability, the iron reduction rate of the coated and bare NPs by Geobacter sulfurreducens was the same, which shows that the PAA coating does not significantly reduce NP Fe(III) bioavailability. Our results demonstrate that much improved transport of iron oxide NP can be achieved in saturated aquifer sediments by introducing negatively charged polyelectrolytes and optimizing polymer concentrations, and furthermore, these coated NPs retain their bioavailability that is needed for applications in bio-environmental remediation.

Permeation enhancing polymers in oral delivery of hydrophilic macromolecules: thiomer/GSH systems.

PubMed

Bernkop-Schnürch, A; Kast, C E; Guggi, D

2003-12-05

Thiolated polymers (= thiomers) in combination with reduced glutathione (GSH) were shown to improve the uptake of hydrophilic macromolecules from the GI tract. The mechanism responsible for this permeation enhancing effect seems to be based on the thiol groups of the polymer. These groups inhibit protein tyrosine phosphatase, being involved in the closing process of tight junctions, via a GSH-mediated mechanism. The strong permeation enhancing effect of various thiomer/GSH systems such as poly(acrylic acid)-cysteine/GSH or chitosan-4-thio-butylamidine (chitosan-TBA)/GSH could be shown via permeation studies on freshly excised intestinal mucosa in Ussing-type chambers. Furthermore, the efficacy of the system was also shown in vivo. By utilizing poly(acrylic acid)-cysteine/GSH as carrier matrix, an absolute oral bioavailability for low molecular weight heparin of 19.9 +/- 9.3% and a pharmacological efficacy--calculated on the basis of the areas under the reduction in serum glucose levels of the oral formulation versus subcutaneous (s.c.) injection-for orally given insulin of 7% could be achieved. The incorporation of salmon calcitonin in chitosan-TBA/GSH led on the other hand to a pharmacological efficacy based on the areas under the reduction in plasma calcium levels of the oral thiomer formulation versus intravenous (i.v.) injection of 1.3%. Because of this high efficacy (i), the possibility to combine thiomer/GSH systems with additional low molecular weight permeation enhancers acting in other ways (ii) and minimal toxicological risks as these polymers are not absorbed from the GI tract (iii), thiolated polymers represent a promising novel tool for the oral administration of hydrophilic macromolecules.

Understanding the surface properties and rheology of a silica suspension mediated by a comb-type poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) copolymer: effect of salinity.

PubMed

Yang, Dingzheng; Yan, Bin; Xiang, Li; Xu, Haolan; Wang, Xiaogang; Zeng, Hongbo

2018-06-13

Understanding the surface properties and rheology of colloidal suspensions in the presence of polymer additives with high salinity are of great importance in formulating construction materials and optimizing process conditions in the mining and petroleum industry. In this work, the surface properties and rheology of a model spherical silica aqueous suspension mediated by a comb-type poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) copolymer at various salt concentrations have been investigated. Adsorption measurements using a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) align well with zeta potential tests and show that polymer adsorption on silica surfaces is enhanced at high salinity (i.e., 3 M NaCl) than at low salinity (i.e., 1 mM NaCl) due to the suppression of the electrical double layer. Surface Forces Apparatus (SFA) measurements reveal that for interactions between two mica surfaces (the basal plane of which has a similar structure as silica) at a high polymer concentration (e.g., 2 wt%), steric repulsion dominates in 1 mM NaCl while bridging attraction is observed in 3 M NaCl. Surface force measurements agree with rheological results on silica suspensions with 0.5 to 2 wt% of PAA/PEO addition, which shows a significant decrease in yield stress in 1 mM NaCl due to steric repulsion but an insignificant variation in yield stress in 3 M NaCl due to attractive bridging interactions. This work provides useful information regarding the surface properties and rheological properties of comb-type polymer-mediated silica suspensions under different salinity conditions, with implications on designing and processing complex colloidal suspensions with polymer additives for various applications.

Self-initiation of UV photopolymerization reactions using tetrahalogenated bisphenol A (meth)acrylates.

PubMed

Pelras, Théophile; Knolle, Wolfgang; Naumov, Sergej; Heymann, Katja; Daikos, Olesya; Scherzer, Tom

2017-05-17

The potential of tetrachlorinated and tetrabrominated bisphenol A diacrylates and dimethacrylates for self-initiation of a radical photopolymerization was investigated. The kinetics of the photopolymerization of an acrylic model varnish containing halogenated monomers was studied by real-time FTIR spectroscopy, whereas the formation of reactive species and secondary products was elucidated by laser flash photolysis and product analysis by GC-MS after steady-state photolysis. The interpretation of the experimental data and the analysis of possible reaction pathways were assisted by quantum chemical calculations. It was shown that all halogenated monomers lead to a significant acceleration of the photopolymerization kinetics at a minimum concentration of 5 wt%. Steady-state and laser flash photolysis measurements as well as quantum chemical calculations showed that brominated and chlorinated samples do not follow the same pathway to generate radical species. Whereas chlorinated (meth)acrylates may cleave only at the C-O bonds of the carboxyl groups resulting in acrolein and oxyl radicals for initiation, brominated monomers may cleave either at the C-O bonds or at the C-Br bonds delivering aryl and bromine radicals. The quantum yields for the photolysis of the halogenated monomers were found to be in the order of 0.1 for acrylates and 0.2 for methacrylates (with an estimated error of 25%), independently of the attached Br and Cl halogens. Finally, the trihalogenated bisphenol A di(meth)acrylate radicals and the acrolein radicals were found to show the highest efficiencies for the reaction with another acrylic double bond leading to the formation of a polymer network.

Synthesis of molecular imprinting polymers for extraction of gallic acid from urine.

PubMed

Bhawani, Showkat Ahmad; Sen, Tham Soon; Ibrahim, Mohammad Nasir Mohammad

2018-02-21

The molecularly imprinted polymers for gallic acid were synthesized by precipitation polymerization. During the process of synthesis a non-covalent approach was used for the interaction of template and monomer. In the polymerization process, gallic acid was used as a template, acrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobisisobutyronitrile as an initiator and acetonitrile as a solvent. The synthesized imprinted and non-imprinted polymer particles were characterized by using Fourier-transform infrared spectroscopy and scanning electron microscopy. The rebinding efficiency of synthesized polymer particles was evaluated by batch binding assay. The highly selective imprinted polymer for gallic acid was MIPI1 with a composition (molar ratio) of 1:4:20, template: monomer: cross-linker, respectively. The MIPI1 showed highest binding efficiency (79.50%) as compared to other imprinted and non-imprinted polymers. The highly selective imprinted polymers have successfully extracted about 80% of gallic acid from spiked urine sample.

Potassium fulvate-modified graft copolymer of acrylic acid onto cellulose as efficient chelating polymeric sorbent.

PubMed

Mohamed, Magdy F; Essawy, Hisham A; Ammar, Nabila S; Ibrahim, Hanan S

2017-01-01

Acrylic acid (AA) was graft copolymerized from cellulose (Cell) in presence of potassium fulvate (KF) in order to enhance the chemical activity of the resulting chelating polymer and the handling as well. Fourier transform infrared (FTIR) proved that KF was efficiently inserted and became a permanent part of the network structure of the sorbent in parallel during the grafting copolymerization. Scanning electron microscopy (SEM) revealed intact homogeneous structure with uniform surface. This indicates improvement of the handling, however, it was not the case for the graft copolymer of acrylic acid onto cellulose in absence of KF, which is known to be brittle and lacks mechanical integrity. Effective insertion of this co-interpenetrating agent provided more functional groups, such as OH and COOH, which improved the chelating power of the produced sorbent as found for the removal of Cu 2+ ions from its aqueous solutions (the removal efficiency reached ∼98.9%). Different models were used to express the experimental data. The results corroborated conformity of the pseudo-second order kinetic model and Langmuir isotherm model to the sorption process, which translates into dominance of the chemisorption. Regeneration of the chelating polymers under harsh conditions did not affect the efficiency of copper ions uptake up to three successive cycles. A thermodynamic investigation ensured exothermic nature of the adsorption process that became less favourable at higher temperatures. Copyright © 2016 Elsevier B.V. All rights reserved.

Resist Rolymers. 8. Thermolysis of Bromine Containing Acrylate Polymers.

DTIC Science & Technology

1987-06-01

bromine containing polymers is particularly interesting because of their role as proven flame retardants . The bromine ...BrI IC COOH I -co2 (1 CH MeI I Br --- CH 2 ---- The presence of bromine on ester units apparently alters the principal mode of degradation of the...CH2---C C--- I I I I C-O C-O C C=O 0’ OCH2CH2Br 0 0 + ’OCH2CH 2Br (6) As described earlier6 bromoethoxy radical loose bromine atom at

Carbon nanoscrolls by pyrolysis of a polymer

NASA Astrophysics Data System (ADS)

Yadav, Prasad; Warule, Sambhaji; Jog, Jyoti; Ogale, Satishchandra

2012-12-01

3D network of carbon nanoscrolls was synthesized starting from pyrolysis of poly(acrylic acid-co-maleic acid) sodium salt. It is a catalyst-free process where pyrolysis of polymer leads to formation of carbon form and sodium carbonate. Upon water soaking of pyrolysis product, the carbon form undergoes self-assembly to form carbon nanoscrolls. The interlayer distance between the walls of carbon nanoscroll was found to be 0.34 nm and the carbon nanoscrolls exhibited a surface area of 188 m2/g as measured by the BET method.

Calcium-tolerant N-substituted acrylamides as thickeners for aqueous systems

DOEpatents

McCormick, Charles L.; Blackmon, Kenneth P.

1987-01-01

A water-soluble, charged, random copolymer of acrylamide and an alkali metal salt of an acrylamido-alkanoic acid such as alkali metal 3-acrylamido-3-methylbutanoate, having an average molecular weight of greater than about 50,000, has been found to maintain unusually stable and effective viscosities in the presence of salts such as NaCl and CaCl.sub.2 when added to water in minor amounts, thus making it a highly effective mobility control agent for secondary and tertiary oil recovery methods. Also within the scope of the invention are the acid form of the polymer, as well as terpolymers which additionally contain olefinically unsaturated monomers such as acrylic acid or sodium acrylate.

Calcium-tolerant N-substituted acrylamides as thickeners for aqueous systems

DOEpatents

McCormick, C.L.; Blackmon, K.P.

1987-03-10

A water-soluble, charged, random copolymer of acrylamide and an alkali metal salt of an acrylamido-alkanoic acid such as alkali metal 3-acrylamido-3-methylbutanoate, having an average molecular weight of greater than about 50,000, has been found to maintain unusually stable and effective viscosities in the presence of salts such as NaCl and CaCl[sub 2] when added to water in minor amounts, thus making it a highly effective mobility control agent for secondary and tertiary oil recovery methods. Also within the scope of the invention are the acid form of the polymer, as well as terpolymers which additionally contain olefinically unsaturated monomers such as acrylic acid or sodium acrylate.

Manganese oxide electrochemical capacitor with potassium poly(acrylate) hydrogel electrolyte

NASA Astrophysics Data System (ADS)

Lee, Kuang-Tsin; Wu, Nae-Lih

An aqueous gel electrolyte has for the first time been successfully applied to the MnO 2· nH 2O-based pseudocapacitive electrochemical capacitors (ECs). The gel electrolyte is made of potassium poly(acrylate) (PAAK) polymer and aqueous solution of KCl. With the selected composition, PAAK:KCl:H 2O = 9.0%:6.7%:84.3% by weight, the gel shows no fluidity, possessing an ionic conductivity in the order of 10 -1 S cm -1. The gel electrolyte has been found to give substantially higher specific capacitances than those in the liquid electrolyte with the same salt (KCl) composition (1 M) and high power capability (>10 kW/kg).

New regioselective derivatives of sucrose with amino acid and acrylic groups.

PubMed

Anders, Jan; Buczys, Rachel; Lampe, Elmar; Walter, Martin; Yaacoub, Emile; Buchholz, Klaus

2006-02-27

We report here a range of new sucrose derivatives obtained from '3-ketosucrose' in aqueous medium with few reaction steps. As an intermediate, 3-amino-3-deoxy-alpha-D-allopyranosyl beta-D-fructofuranoside (1) was obtained via the classical route of reductive amination with much improved yield and high stereoselectivity. Building blocks for polymerization were synthesized by introduction of acrylic-type side chains, for example, with methacrylic anhydride. Corresponding polymers were synthesized. Aminoacyl and peptide conjugates were obtained through conventional peptide synthesis with activated and protected amino acids. Deprotection yielded new glycoderivatives having an unconventional substitution pattern, namely 3-(aminoacylamino) allosaccharides. Both mono- and di-peptide conjugates of allosucrose have been synthesized.

Development of a special purpose spacecraft interior coating, phase 1

NASA Technical Reports Server (NTRS)

Bartoszek, E. J.; Nannelli, P.

1975-01-01

Coating formulations were developed consisting of latex blends of fluorocarbon polymers, acrylic resins, stabilizers, modifiers, other additives, and a variety of inorganic pigments. Suitable latex primers were also developed from an acrylic latex base. The formulations dried to touch in about one hour and were fully dry in about twenty-four hours under normal room temperature and humidity conditions. The resulting coatings displayed good optical and mechanical properties, including excellent bonding to (pre-treated) substrates. In addition, the preferred compositions were found to be self-extinguishing when applied to nonflammable substrates and could meet the offgassing requirements specified by NASA for the intended application. Improvements are needed in abrasion resistance and hardness.

Electrochromatography on acrylate-based monolith in cyclic olefin copolymer microchip: an attractive technology.

PubMed

Ladner, Y; Cretier, G; Faure, K

2015-01-01

Electrochromatography (EC) on a porous monolithic stationary phase prepared within the channels of a microsystem is an attractive alternative for on-chip separation. It combines the separation mechanisms of electrophoresis and liquid chromatography. Moreover, the porous polymer monolithic materials have become popular as stationary phase due to the ease and rapidity of fabrication via free radical photopolymerization. Here, we describe a hexyl acrylate (HA)-based porous monolith which is simultaneously in situ synthesized and anchored to the inner walls of the channel of a cyclic olefin copolymer (COC) device in only 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is realized.

Electron beam surface modifications in reinforcing and recycling of polymers

NASA Astrophysics Data System (ADS)

Czvikovszky, T.; Hargitai, H.

1997-08-01

Thermoplastic polymers can be fiber-reinforced in the recycling step through a reactive modification of the interface between the polymer matrix and fiber. Recollected automobile bumpers made of polypropylene copolymers have been reinforced during the reprocessing with eight different types of high-strength fibers, with waste cord-yarns of the tire industry. A thin layer reactive interface of acrylic oligomers has been applied and activated through low energy (175 keV) electron beam (EB). The upcycling (upgrading recycling) resulted in a series of extrudable and injection-mouldable, fiber-reinforced thermoplastic of enhanced bending strength, increased modulus of elasticity and acceptable impact strength. EB treatment has been compared with conventional methods.

Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies

NASA Astrophysics Data System (ADS)

Docters, E. H.; Smolko, E. E.; Suarez, C. E.

The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

40 CFR 63.11398 - What definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...? Acrylic fiber means a manufactured synthetic fiber in which the fiber-forming substance is any long-chain...) Fails to meet any term or condition that is adopted to implement an applicable requirement in this... fiber-forming substance is any long-chain synthetic polymer composed of at least 35 percent by weight of...

Strand Burner Results of AFP-001 Propellant with Inert Coating for Temperature Compensation

DTIC Science & Technology

2015-10-01

there were 4 different configurations: baseline, a C-100 coated, an SC-11 coated, and a urethane acrylate (UA) coated. C-100 is a polyurea based...phenomena associated with coated AFP-001 propellant. Three different coating polymers were chosen for the experiments: an epoxy (SC-11), polyurea (C-100

Photoinduced Formation and Characterization of Metallic Silver and Gold Particles in VYCOR (trademark) Glass

DTIC Science & Technology

2004-12-01

agent such as citric acid or sodium borohydride. Other systems have been studied in which polymers such as poly vinyl alcohol/poly acrylic acid or...Wu, M. H., Henderson, D. O., Malone, K., Mills, G., Meldrum , A., Proceedings of the Electrochemical Society, 1999, 98-11, 439.

Response to Comments on "Degradability of an Acrylate-Linked, Fluorotelomer Polymer in Soil"

EPA Science Inventory

We thank Russell et al for their careful comments on our paper. We address their comments, however, in all this detail, we emphasize that it is important not to lose track of several overarching issues that we address here and in Supporting Information: (1) We observed an excess ...

Iron-Based Redox Polymerization of Acrylic Acid for Direct Synthesis of Hydrogel/Membranes, and Metal Nanoparticles for Water Treatment

PubMed Central

Hernández, Sebastián; Papp, Joseph K.; Bhattacharyya, Dibakar

2014-01-01

Functionalized polymer materials with ion exchange groups and integration of nano-structured materials is an emerging area for catalytic and water pollution control applications. The polymerization of materials such as acrylic acid often requires persulfate initiator and a high temperature start. However, is generally known that metal ions accelerate such polymerizations starting from room temperature. If the metal is properly selected, it can be used in environmental applications adding two advantages simultaneously. This paper deals with this by polymerizing acrylic acid using iron as accelerant and its subsequent use for nanoparticle synthesis in hydrogel and PVDF membranes. Characterizations of hydrogel, membranes and nanoparticles were carried out with different techniques. Nanoparticles sizes of 30–60 nm were synthesized. Permeability and swelling measurements demonstrate an inverse relationship between hydrogel mesh size (6.30 to 8.34 nm) and membrane pores (222 to 110 nm). Quantitative reduction of trichloroethylene/chloride generation by Fe/Pd nanoparticles in hydrogel/membrane platforms was also performed. PMID:24954975

Antibiotic-conjugated polyacrylate nanoparticles: new opportunities for development of anti-MRSA agents.

PubMed

Turos, Edward; Shim, Jeung-Yeop; Wang, Yang; Greenhalgh, Kerriann; Reddy, G Suresh Kumar; Dickey, Sonja; Lim, Daniel V

2007-01-01

This report describes the preparation of polyacrylate nanoparticles in which an N-thiolated beta-lactam antibiotic is covalently conjugated onto the polymer framework. These nanoparticles are formed in water by emulsion polymerization of an acrylated antibiotic pre-dissolved in a liquid acrylate monomer (or mixture of co-monomers) in the presence of sodium dodecyl sulfate as a surfactant and potassium persulfate as a radical initiator. Dynamic light scattering analysis and electron microscopy images of these emulsions show that the nanoparticles are approximately 40 nm in diameter. The emulsions have potent in vitro antibacterial properties against methicillin-resistant Staphylococcus aureus and have improved bioactivity relative to the non-polymerized form of the antibiotic. A unique feature of this methodology is the ability to incorporate water-insoluble drugs directly into the nanoparticle framework without the need for post-synthetic modification. Additionally, the antibiotic properties of the nanoparticles can be modulated by changing the length or location of the acrylate linker on the drug monomer.

A green approach to prepare silver nanoparticles loaded gum acacia/poly(acrylate) hydrogels.

PubMed

Bajpai, S K; Kumari, Mamta

2015-09-01

In this work, gum acacia (GA)/poly(sodium acrylate) semi-interpenetrating polymer networks (Semi-IPN) have been fabricated via free radical initiated aqueous polymerization of monomer sodium acrylate (SA) in the presence of dissolved Gum acacia (GA), using N,N'-methylenebisacrylamide (MB) as cross-linker and potassium persulphate (KPS) as initiator. The semi-IPNs, synthesized, were characterized by various techniques such as X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The dynamic water uptake behavior of semi-IPNs was investigated and the data were interpreted by various kinetic models. The equilibrium swelling data were used to evaluate various network parameters. The semi-IPNs were used as template for the in situ preparation of silver nanoparticles using extract of Syzygium aromaticum (clove). The formation of silver nanoparticles was confirmed by surface plasmon resonance (SPR), XRD and transmission electron microscopy (TEM). Finally, the antibacterial activity of GA/poly(SA)/silver nanocomposites was tested against E. coli. Copyright © 2015 Elsevier B.V. All rights reserved.

Control the wettability of poly(n-isopropylacrylamide-co-1-adamantan-1-ylmethyl acrylate) modified surfaces: the more Ada, the bigger impact?

PubMed

Shi, Xiu-Juan; Chen, Gao-Jian; Wang, Yan-Wei; Yuan, Lin; Zhang, Qiang; Haddleton, David M; Chen, Hong

2013-11-19

Surface-initiated SET-LRP was used to synthesize polymer brush containing N-isopropylacrylamide and adamantyl acrylate using Cu(I)Cl/Me6-TREN as precursor catalyst and isopropanol/H2O as solvent. Different reaction conditions were explored to investigate the influence of different parameters (reaction time, catalyst concentration, monomer concentration) on the polymerization. Copolymers with variable 1-adamantan-1-ylmethyl acrylate (Ada) content and comparable thickness were synthesized onto silicon surfaces. Furthermore, the hydrophilic and bioactive molecule β-cyclodextrin-(mannose)7 (CDm) was synthesized and complexed with adamantane via host-guest interaction. The effect of adamantane alone and the effect of CDm together with adamantane on the wettability and thermoresponsive property of surface were investigated in detail. Experimental and molecular structure analysis showed that Ada at certain content together with CDm has the greatest impact on surface wettability. When Ada content was high (20%), copolymer-CDm surfaces showed almost no CDm complexed with Ada as the result of steric hindrance.

Europium-doped aluminum oxide phosphors as indicators for frontal polymerization dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carranza, Arturo; Gewin, Mariah; Pojman, John A., E-mail: japojman@lsu.edu

2014-06-15

In this study, we present an inexpensive and practical method that allows the monitoring and visualization of front polymerization, propagation, and dynamics. Commercially available europium-doped aluminum oxide powders were combined with video imaging to visualize free-radical propagating polymer fronts. In order to demonstrate the applicability of this method, frontal copolymerization reactions of propoxylated glycerin triacrylate (EB53), pentaerythritol triacrylate (PETA), and pentaerythritol tetra-acrylate (PETEA) with 1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (Luperox 231®) as an initiator were studied and compared to the results obtained by IR imaging. Systems exhibiting higher filler loading, higher EB53 content, and less acrylated monomers showed a marked decrease in front velocity,more » while those with more acrylated monomers and higher crosslinking density showed a marked increase in front velocity. Finally, in order to show the potential of the imaging technique, we studied fronts propagating in planar and spherical geometries.« less

Molecularly designed water soluble, intelligent, nanosize polymeric carriers.

PubMed

Pişkin, Erhan

2004-06-11

Intelligent polymers, also referred as "stimuli-responsive polymers" undergo strong property changes (in shape, surface characteristics, solubility, etc.) when only small changes in their environment (changes in temperature, pH, ionic strength light, electrical and magnetic field, etc.). They have been used in several novel applications, drug delivery systems, tissue engineering scaffolds, bioseparation, biomimetic actuators, etc. The most popular member of these type of polymers is poly(N-isopropylacrylamide) (poly(NIPA)) which exhibits temperature-sensitive character, in which the polymer chains change from water-soluble coils to water-insoluble globules in aqueous solution as temperature increases above the lower critical solution temperature (LCST) of the polymer. Copolymerization of NIPA with acrylic acid (AAc) allows the synthesis of both pH and temperature-responsive copolymers. This paper summarizes some of our related studies in which NIPA and its copolymers were synthesized and used as intelligent carriers in diverse applications.

A plasticized polymer-electrolyte-based photoelectrochemical solar cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, D.; Ibrahim, M.A.; Frank, A.J.

1998-01-01

A photoelectrochemical solar cell based on an n-GaAs/polymer-redox-electrolyte junction is reported. Di(ethylene glycol) ethyl ether acrylate containing ferrocene as a redox species and benzoin methyl ether as a photoinitiator is polymerized in situ. Propylene carbonate is used as a plasticizer to improve the conductivity of the polymer redox electrolyte. For thin (1 {micro}m) polymer electrolytes, the series resistance of the cell is negligible. However, the short-circuit photocurrent density of the cell at light intensities above 10 mW/cm{sup 2} is limited by mass transport of redox species within the polymer matrix. At a light intensity of 70 mW/cm{sup 2}, a moderatemore » light-to-electrical energy conversion efficiency (3.1%) is obtained. The interfacial charge-transfer properties of the cell in the dark and under illumination are studied.« less

Polymer surface functionalities that control human embryoid body cell adhesion revealed by high throughput surface characterization of combinatorial material microarrays

PubMed Central

Yang, Jing; Mei, Ying; Hook, Andrew L.; Taylor, Michael; Urquhart, Andrew J.; Bogatyrev, Said R.; Langer, Robert; Anderson, Daniel G.; Davies, Martyn C.; Alexander, Morgan R.

2010-01-01

High throughput materials discovery using combinatorial polymer microarrays to screen for new biomaterials with new and improved function is established as a powerful strategy. Here we combine this screening approach with high throughput surface characterisation (HT-SC) to identify surface structure-function relationships. We explore how this combination can help to identify surface chemical moieties that control protein adsorption and subsequent cellular response. The adhesion of human embryoid body (hEB) cells to a large number (496) of different acrylate polymers synthesized in a microarray format is screened using a high throughput procedure. To determine the role of the polymer surface properties on hEB cell adhesion, detailed HT-SC of these acrylate polymers is carried out using time of flight secondary ion mass spectrometry (ToF SIMS), x-ray photoelectron spectroscopy (XPS), pico litre drop sessile water contact angle (WCA) measurement and atomic force microscopy (AFM). A structure-function relationship is identified between the ToF SIMS analysis of the surface chemistry after a fibronectin (Fn) pre-conditioning step and the cell adhesion to each spot using the multivariate analysis technique partial least squares (PLS) regression. Secondary ions indicative of the adsorbed Fn correlate with increased cell adhesion whereas glycol and other functionalities from the polymers are identified that reduce cell adhesion. Furthermore, a strong relationship between the ToF SIMS spectra of bare polymers and the cell adhesion to each spot is identified using PLS regression. This identifies a role for both the surface chemistry of the bare polymer and the pre-adsorbed Fn, as-represented in the ToF SIMS spectra, in controlling cellular adhesion. In contrast, no relationship is found between cell adhesion and wettability, surface roughness, elemental or functional surface composition. The correlation between ToF SIMS data of the surfaces and the cell adhesion demonstrates the ability of identifying surface moieties that control protein adsorption and subsequent cell adhesion using ToF SIMS and multivariate analysis. PMID:20832108

Preparation and application of the sol-gel-derived acrylate/silicone co-polymer coatings for headspace solid-phase microextraction of 2-chloroethyl ethyl sulfide in soil.

PubMed

Liu, Mingming; Zeng, Zhaorui; Fang, Huaifang

2005-05-27

Three types of novel acrylate/silicone co-polymer coatings, including co-poly(methyl acrylate/hydroxy-terminated silicone oil) (MA/OH-TSO), co-poly(methyl methacrylate/OH-TSO) (MMA/OH-TSO) and co-poly(butyl methacrylate/OH-TSO) (BMA/OH-TSO), were prepared for the first time by sol-gel method and cross-linking technology and subsequently applied to headspace solid-phase microextraction (HS-SPME) of 2-chloroethyl ethyl sulfide (CEES), a surrogate of mustard, in soil. The underlying mechanisms of the coating process were discussed and confirmed by IR spectra. The selectivity of the three types of sol-gel-derived acrylate/silicone coated fibers was studied, and the BMA/OH-TSO coated fibers exhibited the highest extraction ability to CEES. The concentration of BMA and OH-TSO in sol solution was optimized, and the BMA/OH-TSO (3:1)-coated fibers possessed the highest extraction efficiency. Compared with commercially available polyacrylate (PA) fiber, the sol-gel-derived BMA/OH-TSO (3:1) fibers showed much higher extraction efficiency to CEES. Therefore, the BMA/OH-TSO (3:1)-coated fibers were chosen for the analysis of CEES in soil matrix. The reproducibility of coating preparation was satisfactory, with the RSD 2.39% within batch and 3.52% between batches, respectively. The coatings proved to be quite stable at high temperature (to 350 degrees C) and in different solvents (organic or inorganic), thus their lifetimes (to 150 times) are longer than conventional fibers. Extraction parameters, such as the volume of water added to the soil, extraction temperature and time, and the ionic strength were optimized. The linearity was from 0.1 to 10 microg/g, the limit of detection (LOD) was 2.7 ng/g, and the RSD was 2.19%. The recovery of CEES was 88.06% in agriculture soil, 92.61% in red clay, and 101.95% in sandy soil, respectively.

Responsive copolymers for enhanced petroleum recovery. Second annual report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCormick, C.; Hester, R.

The authors describe second year efforts in synthesis, characterization, and rheology to develop polymers with significantly improved efficiency in mobility control and conformance. These advanced polymer systems would maintain high viscosities or behave as virtual gels under low shear conditions and at elevated electrolyte concentrations. At high fluid shear rates, associates would deaggregate yielding low viscosity solutions, reducing problems of shear degradation or face plugging during injection. Polymeric surfactants were also developed with potential for use in higher salt, higher temperature reservoirs for mobilization of entrapped oil. Chapters include: Ampholytic terpolymers of acrylamide with sodium 3-acrylamido-3-methylbutanoate and 2-acrylamido-2-methylpropanetrimethylammonium chloride; Hydrophilicmore » sulfobetaine copolymers of acrylamide and 3-(2-acrylamido-methylpropane-dimethylammonio)-1-propanesulfonate; Copolymerization of maleic anhydride and N-vinylformamide; Reactivity ratio of N-vinylformamide with acrylamide, sodium acrylate, and n-butyl acrylate; Effect of the distribution of the hydrophobic cationic monomer dimethyldodecyl(2-acrylamidoethyl)ammonium bromide on the solution behavior of associating acrylamide copolymers; Effect of surfactants on the solution properties of amphipathic copolymers of acrylamide and N,N-dimethyl-N-dodecyl-N-(2-acrylamidoethyl)ammonium bromide; Associative interactions and photophysical behavior of amphiphilic terpolymers prepared by modification of maleic anhydride/ethyl vinyl ether copolymers; Copolymer compositions of high-molecular-weight functional acrylamido water-soluble polymers using direct-polarization magic-angle spinning {sup 13}C NMR; Use of factorial experimental design in static and dynamic light scattering characterization of water soluble polymers; and Porous medium elongational rheometer studies of NaAMB/AM copolymer solutions.« less

Synthesis and characterization of antifouling poly(N-acryloylaminoethoxyethanol) with ultralow protein adsorption and cell attachment.

PubMed

Chen, Hong; Zhang, Mingzhen; Yang, Jintao; Zhao, Chao; Hu, Rundong; Chen, Qiang; Chang, Yung; Zheng, Jie

2014-09-02

Rational design of effective antifouling polymers is challenging but important for many fundamental and applied applications. Herein we synthesize and characterize an N-acryloylaminoethoxyethanol (AAEE) monomer, which integrates three hydrophilic groups of hydroxyl, amide, and ethylene glycol in the same material. AAEE monomers were further grafted and polymerized on gold substrates to form polyAAEE brushes with well-controlled thickness via surface-initiated atomic transfer radical polymerization (SI-ATRP), with particular attention to a better understanding of the molecular structure-antifouling property relationship of hydroxyl-acrylic-based polymers. The surface hydrophilicity and antifouling properties of polyAAEE brushes as a function of film thickness are studied by combined experimental and computational methods including surface plasmon resonance (SPR) sensors, atomic force microscopy (AFM), cell adhesion assay, and molecular dynamics (MD) simulations. With the optimal polymer film thicknesses (∼10-40 nm), polyAAEE-grafted surfaces can effectively resist protein adsorption from single-protein solutions and undiluted human blood plasma and serum to a nonfouling level (i.e., <0.3 ng/cm(2)). The polyAAEE brushes also highly resist mammalian cell attachment up to 3 days. MD simulations confirm that the integration of three hydrophilic groups induce a stronger and closer hydration layer around polyAAEE, revealing a positive relationship between surface hydration and antifouling properties. The molecular structure-antifouling properties relationship of a series of hydroxyl-acrylic-based polymers is also discussed. This work hopefully provides a promising structural motif for the design of new effective antifouling materials beyond traditional ethylene glycol-based antifouling materials.

Metal chelation dual-template epitope imprinting polymer via distillation-precipitation polymerization for recognition of porcine serum albumin.

PubMed

Qin, Ya-Ping; Wang, Hai-Yan; He, Xi-Wen; Li, Wen-You; Zhang, Yu-Kui

2018-08-01

A novel dual-template epitope imprinting polymer coated on magnetic carbon nanotubes (MCNTs@D-EMIP) was successfully prepared for specific recognition of porcine serum albumin (PSA) via dual-template epitope imprinting, metal chelation imprinting and distillation-precipitation polymerization (DPP). C-terminal peptides and N-terminal peptides of PSA were selected as templates simultaneously, and zinc acrylate and ethylene glycol dimethacrylate (EGDMA) were used as functional monomer and cross-linker, respectively. The epitope templates were immobilized by metal chelation and six-membered ring formed with zinc acrylate. Finally, MCNTs@D-EMIP was synthesized by DPP in only 30 min, which was much shorter than those of other polymerization methods. The prepared MCNTs@D-EMIP displayed specific recognition ability toward PSA and its adsorption amount and imprinting factor were 45.05 mg g -1 and 4.50, which were much higher than those of single template epitope imprinting polymers. Besides, high-performance liquid chromatography (HPLC) analysis of PSA in porcine blood serum real sample indicated that the specificity was not affected by other competitive proteins, which forcefully stated that the MCNTs@D-EMIP had potential to be applied in bio-separation area. In addition, the results of cross-reactivity experiment proved that this strategy had generality to prepare dual-template epitope imprinting polymer for recognition of target protein. In summary, this study provided an efficient protocol to recognize target protein in complex sample via dual-template epitope imprinting approach, metal chelation imprinting and distillation-precipitation polymerization. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of γ-radiation induced polymerization in ethyl methacrylate and methyl acrylate monomers solutions

NASA Astrophysics Data System (ADS)

Baccaro, Stefania; Casieri, Cinzia; Cemmi, Alessia; Chiarini, Marco; D'Aiuto, Virginia; Tortora, Mariagrazia

2017-12-01

The present work is focused on the γ-radiation induced polymerization of ethyl methacrylate (EMA) and methyl acrylate (MA) monomers mixture to obtain a co-polymer with specific features. The effect of the irradiation parameters (radiation absorbed dose, dose rate) and of the environmental atmosphere on the features of the final products was investigated. Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Nuclear Magnetic Resonance high-resolution analyses of hydrogen and carbon nuclei (1H and 13C NMR) were applied to follow the γ-induced modifications by monitoring the co-polymerization process and allowed the irradiation parameters optimization. Diffusion-Ordered NMR (DOSY-NMR) data were used to evaluate the co-polymers polydispersity and polymerization degree. Since the last parameter is strongly influenced by the γ radiation and environmental conditions, a comparison among samples prepared and irradiated in air and under nitrogen atmosphere was carried out. In presence of oxygen, higher radiation was required to obtain a full solid co-polymer since a partial amount of energy released to the samples was involved in competitive processes, i.e. oxygen-containing free radicals formation and primary radicals recombination. Irrespectively to the environmental atmosphere, more homogeneous samples in term of polymerization degree dispersion was achieved at lower dose rates. At radiation absorbed doses higher than those needed for the formation of the co-polymer, while in case of samples irradiated in air heavy depolymerization was verified, a sensible increase of the samples stability was attained if the irradiation was performed under nitrogen atmosphere.

Synthesis of poly(N-isopropylacrylamide)-co-poly(phenylboronate ester) acrylate and study on their glucose-responsive behavior.

PubMed

Yao, Yuan; Shen, Heyun; Zhang, Guanghui; Yang, Jing; Jin, Xu

2014-10-01

We introduced thermo-sensitive poly(N-isopropylacrylamide) (PNIPAM) into the polymer structure of poly(ethylene glycol)-block-poly(phenylboronate ester) acrylate (MPEG-block-PPBDEMA) by block and random polymerization pathways in order to investigate the effect of polymer architecture on the glucose-responsiveness and enhance their insulin release controllability. By following the structure, the continuous PNIPAM shell of the triblock polymer MPEG-block-PNIPAM-block-PPBDEMA collapsing on the glucose-responsive PPBDEMA core formed the polymeric micelles with a core-shell-corona structure, and MPEG-block-(PNIPAM-rand-PPBDEMA) exhibited core-corona micelles in which the hydrophobic core consisted of PNIPAM and PPBDEMA segments when the environmental temperature was increased above low critical solution temperature (LCST) of PNIPAM. The micellar morphologies can be precisely controlled by temperature change between 15 and 37°C. As a result, the introduction of PNIPAM greatly enhanced the overall stability of insulin encapsulated in the polymeric micelles in the absence of glucose over incubation 80 h at 37°C. Comparing to MPEG-block-PNIPAM-block-PPBDEMA, the nanocarriers from MPEG-block-(PNIPAM-rand-PPBDEMA) showed great insulin release behavior which is zero insulin release without glucose, low release at normal blood glucose concentration (1.0 mg/mL). Therefore, these nanocarriers may be served as promising self-regulated insulin delivery system for diabetes treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

Adsorption of ammonium and phosphate by feather protein based semi-interpenetrating polymer networks hydrogel as a controlled-release fertilizer.

PubMed

Su, Yuan; Liu, Jia; Yue, Qinyan; Li, Qian; Gao, Baoyu

2014-01-01

A new feather protein-grafted poly(potassium acrylate)/polyvinyl alcohol (FP-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was produced through graft copolymerization with FP as a basic macromolecular skeletal material, acrylic acid as a monomer and PVA as a semi-IPNs polymer. The adsorption of ammonium and phosphate ions from aqueous solution using the new hydrogel as N and P controlled-release fertilizer with water-retention capacity was studied. The effects of pH value, concentration, contact time and ion strength on NH4+ and PO3-4 removal by FP-g-PKA/PVA semi-IPNs hydrogel were investigated using batch adsorption experiments. The results indicated that the hydrogel had high adsorption capacities and fast adsorption rates for NH4+ and PO3-4 in wide pH levels ranging from 4.0 to 9.0. Kinetic analysis presented that both NH4+ and PO3-4 removal were closely fitted with the pseudo-second-order model. Furthermore, the adsorption isotherms of hydrogel were best represented by the Freundlich model. The adsorption-desorption experimental results showed the sustainable stability of FP-g-PKA/PVA semi-IPNs hydrogel for NH4+ and PO3-4 removal. Overall, FP-g-PKA/PVA could be considered as an efficient material for the removal and recovery of nitrogen and phosphorus with the agronomic reuse as a fertilizer.

A comparison of tackified, miniemulsion core-shell acrylic latex films with corresponding particle-blend films: structure-property relationships.

PubMed

Canetta, Elisabetta; Marchal, Jeanne; Lei, Chun-Hong; Deplace, Fanny; König, Alexander M; Creton, Costantino; Ouzineb, Keltoum; Keddie, Joseph L

2009-09-15

Tackifying resins (TRs) are often added to pressure-sensitive adhesive films to increase their peel strength and adhesion energy. In waterborne adhesives, the TR is dispersed in water using surfactants and then blended with colloidal polymers in water (i.e., latex). In such waterborne systems, there are problems with the colloidal stability and difficulty in applying coatings of the particle blends; the films are often hydrophilic and subject to water uptake. Here, an alternative method of making waterborne, tackified adhesives is demonstrated. The TR is incorporated within the core of colloidal polymer particles via miniemulsion polymerization. Atomic force microscopy (AFM) combined with force spectroscopy analysis reveals there is heterogeneity in the distribution of the TR in films made from particle blends and also in films made from miniemulsion polymers. Two populations, corresponding to TR-rich and acrylic-rich components, were identified through analysis of the AFM force-displacement curves. The nanoscale maximum adhesion force and adhesion energy were found to be higher in a miniemulsion film containing 12 wt % tackifying resin in comparison to an equivalent blended film. The macroscale tack and viscoelasticity are interpreted by consideration of the nanoscale structure and properties. The incorporation of tackifying resin through a miniemulsion polymerization process not only offers clear benefits in the processing of the adhesive, but it also leads to enhanced adhesion properties.

Transparent and Electrically Conductive Carbon Nanotube-Polymer Nanocomposite Materials for Electrostatic Charge Dissipation

NASA Technical Reports Server (NTRS)

Dervishi, E.; Biris, A. S.; Biris, A. R.; Lupu, D.; Trigwell, S.; Miller, D. W.; Schmitt, T.; Buzatu, D. A.; Wilkes, J. G.

2006-01-01

In recent years, nanocomposite materials have been extensively studied because of their superior electrical, magnetic, and optical properties and large number of possible applications that range from nano-electronics, specialty coatings, electromagnetic shielding, and drug delivery. The aim of the present work is to study the electrical and optical properties of carbon nanotube(CNT)-polymer nanocomposite materials for electrostatic charge dissipation. Single and multi-wall carbon nanotubes were grown by catalytic chemical vapor deposition (CCVD) on metal/metal oxide catalytic systems using acetylene or other hydrocarbon feedstocks. After the purification process, in which amorphous carbon and non-carbon impurities were removed, the nanotubes were functionalized with carboxylic acid groups in order to achieve a good dispersion in water and various other solvents. The carbon nanostructures were analyzed, both before and after functionalization by several analytical techniques, including microscopy, Raman spectroscopy, and X-Ray photoelectron spectroscopy. Solvent dispersed nanotubes were mixed (1 to 7 wt %) into acrylic polymers by sonication and allowed to dry into 25 micron thick films. The electrical and optical properties of the films were analyzed as a function of the nanotubes' concentration. A reduction in electrical resistivity, up to six orders of magnitude, was measured as the nanotubes' concentration in the polymeric films increased, while optical transparency remained 85 % or higher relative to acrylic films without nanotubes.

Risk Assessment of residual monomer migrating from acrylic polymers and causing Allergic Contact Dermatitis during normal handling and use.

PubMed

Pemberton, Mark A; Lohmann, Barbara S

2014-08-01

Acrylic, Poly Methyl Methacrylate (PMMA) based polymers are found in many industrial, professional and consumer products and are of low toxicity, but do contain very low levels of residual monomers and process chemicals that can leach out during handling and use. Methyl Methacrylate, the principle monomer is of low toxicity, but is a recognized weak skin sensitizer. The risk of induction of contact allergy in consumers was determined using a method based upon the Exposure-based Quantitative Risk Assessment approach developed for fragrance ingredients. The No Expected Sensitization Induction Level (NESIL) was based on the threshold to induction of sensitization (EC3) in the Local Lymph Node Assay (LLNA) since no Human Repeat Insult Patch Test (HRIPT) data were available. Categorical estimation of Consumer Exposure Level was substituted with a worst case assumption based upon the quantitative determination of MMA monomer migration into simulants. Application of default and Chemical-Specific Adjustment Factors results in a Risk Characterization Ratio (RCR) of 10,000 and a high Margin of Safety for induction of Allergic Contact Dermatitis (ACD) in consumers handling polymers under conservative exposure conditions. Although there are no data available to derive a RCR for elicitation of ACD it is likely to be lower than that for induction. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

[Modern polymers in matrix tablets technology].

PubMed

Zimmer, Łukasz; Kasperek, Regina; Poleszak, Ewa

2014-01-01

Matrix tablets are the most popular method of oral drug administration, and polymeric materials have been used broadly in matrix formulations to modify and modulate drug release rate. The main goal of the system is to extend drug release profiles to maintain a constant in vivo plasma drug concentration and a consistent pharmacological effect. Polymeric matrix tablets offer a great potential as oral controlled drug delivery systems. Cellulose derivatives, like hydroxypropyl methylcellulose (HPMC) are often used as matrix formers. However, also other types of polymers can be used for this purpose including: Kollidon SR, acrylic acid polymers such as Eudragits and Carbopols. Nevertheless, polymers of natural origin like: carragens, chitosan and alginates widely used in the food and cosmetics industry are now coming to the fore of pharmaceutical research and are used in matrix tablets technology. Modern polymers allow to obtain matrix tablets by 3D printing, which enables to develop new formulation types. In this paper, the polymers used in matrix tablets technology and examples of their applications were described.

Toward a versatile toolbox for cucurbit[n]uril-based supramolecular hydrogel networks through in situ polymerization.

PubMed

Liu, Ji; Soo Yun Tan, Cindy; Lan, Yang; Scherman, Oren A

2017-09-15

The success of exploiting cucurbit[ n ]uril (CB[ n ])-based molecular recognition in self-assembled systems has sparked a tremendous interest in polymer and materials chemistry. In this study, polymerization in the presence of host-guest complexes is applied as a modular synthetic approach toward a diverse set of CB[8]-based supramolecular hydrogels with desirable properties, such as mechanical strength, toughness, energy dissipation, self-healing, and shear-thinning. A range of vinyl monomers, including acrylamide-, acrylate-, and imidazolium-based hydrophilic monomers, could be easily incorporated as the polymer backbones, leading to a library of CB[8] hydrogel networks. This versatile strategy explores new horizons for the construction of supramolecular hydrogel networks and materials with emergent properties in wearable and self-healable electronic devices, sensors, and structural biomaterials. © 2017 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3105-3109.

Polymer Characterization by 13C Nuclear Magnetic Resonance (NMR) spectroscopy: Acryloid K125-EA and High Molecular Weight PIBM

DTIC Science & Technology

1980-02-01

average sequence length Butyl acrylate Methyl methacrylate PIBM Carbon-13 Monomer distribution PMMA (Continued on reverse side) 120. ASTACT (VC•T e m...TACTEC Attic SARPH.FTA 1 505 KIng Avenue Ihlle ithlt, AR 71611 Columbus, OH 43201 US ARMY TRAINING & DOCTRINE COMMAND Director or Toxicology

78 FR 55644 - Styrene, Copolymers with Acrylic Acid and/or Methacrylic Acid; Tolerance Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-11

... in residential settings. If EPA is able to determine that a finite tolerance is not necessary to... composition the atomic elements carbon, hydrogen, and oxygen. 3. The polymer does not contain as an integral part of its composition, except as impurities, any element other than those listed in 40 CFR 723.250(d...

78 FR 6213 - Styrene-2-Ethylhexyl Acrylate Copolymer; Tolerance Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-30

.... If EPA is able to determine that a finite tolerance is not necessary to ensure that there is a... composition the atomic elements carbon, hydrogen, and oxygen. 3. The polymer does not contain as an integral part of its composition, except as impurities, any element other than those listed in 40 CFR 723.250(d...

Tung oil-based unsaturated co-ester macromonomer for thermosetting polymers: Synergetic synthesis and copolymerization with styrene

USDA-ARS?s Scientific Manuscript database

A novel unsaturated co-ester (co-UE) macromonomer containing both maleates and acrylates was synthesized from tung oil (TO) and its chemical structure was characterized by FT-IR, 1H-NMR, 13C-NMR, and gel permeation chromatography (GPC). The monomer was synthesized via a new synergetic modification o...

Anti-Icing Chitin Coating System Development

DTIC Science & Technology

1990-10-30

medium. Second, antifouling paints must inhibit barnacles, algae and fungi destruction. Current paints contain TBT , cuprous oxide, mercury, water-soluble... TBT ) copolymer (Intersmooth SPC) erodes slowly but requires expensive hull preparation. Courtauld, Jotun, Kansai Paint and Chugoku Marine Paint...manufacturer TBT -free ablative paints. These paints, however, contain cuprous oxide, mercury, water-soluble acrylic organotin polymer or polysiloxane

Properties of pressure sensitive adhesives found in paper recycling operations

Treesearch

Ryan F. Verhulst; Steven J. Severtson; Jihui Guo; Carl J. Houtman

2006-01-01

Hot melt and water-based adhesives are very different materials with similar physical properties. Their ability to act as adhesives is due to physical bonds and mechanical interlocks which form as adhesive flows into topographical features on the substrate surface. Hot-melt adhesives are based on soft, rubbery polymers while water-based adhesives are usually acrylic...

Chemical modification of magnetite nanoparticles and preparation of acrylic-base magnetic nanocomposite particles via miniemulsion polymerization

NASA Astrophysics Data System (ADS)

Mahdieh, Athar; Mahdavian, Ali Reza; Salehi-Mobarakeh, Hamid

2017-03-01

Nowadays, magnetic nanocomposite particles have attracted many interests because of their versatile applications. A new method for chemical modification of Fe3O4 nanoparticles with polymerizable groups is presented here. After synthesis of Fe3O4 nanoparticles by co-precipitation method, they were modified sequentially with 3-aminopropyl triethoxysilane (APTES), acryloyl chloride (AC) and benzoyl chloride (BC) and all were characterized by FTIR, XRD, SEM and TGA analyses. Then the modified magnetite nanoparticles with unsaturated acrylic groups were copolymerized with methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA) through miniemulsion polymerization. Although several reports exist on preparation of magnetite-base polymer particles, but the efficiency of magnetite encapsulationwith reasonable content and obtaining final stable latexes with limited aggregation ofFe3O4 are still important issues. These were considered here by controlling reaction parameters. Hence, a seriesofmagneticnanocomposites latex particlescontaining different amounts of Fe3O4 nanoparticles (0-10 wt%) were prepared with core-shell morphology and diameter below 200 nm and were characterized by FT-IR, DSC and TGA analyses. Their morphology and size distribution were studied by SEM, TEM and DLS analyses too. Magnetic properties of all products were also measuredby VSM analysis and the results revealed almost superparamagnetic properties for the obtained nanocomposite particles.

Renewable Acrylonitrile Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beckham, Gregg T; Karp, Eric M; Eaton, Todd R

Acrylonitrile (ACN) is a petroleum-derived compound used in resins, polymers, acrylics, and carbon fiber. We present a process for renewable ACN production using 3-hydroxypropionic acid (3-HP), which can be produced microbially from sugars. The process achieves ACN molar yields exceeding 90% from ethyl 3-hydroxypropanoate (ethyl 3-HP) via dehydration and nitrilation with ammonia over an inexpensive titanium dioxide solid acid catalyst. We further describe an integrated process modeled at scale that is based on this chemistry and achieves near-quantitative ACN yields (98 +/- 2%) from ethyl acrylate. This endothermic approach eliminates runaway reaction hazards and achieves higher yields than the standardmore » propylene ammoxidation process. Avoidance of hydrogen cyanide as a by-product also improves process safety and mitigates product handling requirements.« less

Enhanced Dielectric Constant for Efficient Electromagnetic Shielding Based on Carbon-Nanotube-Added Styrene Acrylic Emulsion Based Composite

PubMed Central

2010-01-01

An efficient electromagnetic shielding composite based on multiwalled carbon nanotubes (MWCNTs)-filled styrene acrylic emulsion-based polymer has been prepared in a water-based system. The MWCNTs were demonstrated to have an effect on the dielectric constants, which effectively enhance electromagnetic shielding efficiency (SE) of the composites. A low conductivity threshold of 0.23 wt% can be obtained. An EMI SE of ~28 dB was achieved for 20 wt% MWCNTs. The AC conductivity (σac) of the composites, deduced from imaginary permittivity, was used to estimate the SE of the composites in X band (8.2–12.4 GHz), showing a good agreement with the measured results. PMID:20596498

Incorporation of antimicrobial macromolecules in acrylic denture base resins: a research composition and update.

PubMed

Sivakumar, Indumathi; Arunachalam, Kuthalingam Subbiah; Sajjan, Suresh; Ramaraju, Alluri Venkata; Rao, Bheemalingeshwara; Kamaraj, Bindu

2014-06-01

Contemporary research in acrylic denture base materials focuses on the development of a novel poly(methyl methacrylate) (PMMA) resin with antimicrobial properties. Although PMMA resin has fulfilled all the requirements of an ideal denture base material, its susceptibility to microbial colonization in the oral environment is a formidable concern to clinicians. Many mechanisms including the absence of ionic charge in the methyl methacrylate resins, hydrophobic interactions, electrostatic interactions, and mechanical attachment have been found to contribute to the formation of biofilm. The present article outlines the basic categories of potential antimicrobial polymer (polymeric biocides) formulations (modified PMMA resins) and considers their applicability, biological status, and usage potential over the coming years. © 2013 by the American College of Prosthodontists.

Characterizing mesh size distributions (MSDs) in thermosetting materials using a high-pressure system.

PubMed

Larché, J-F; Seynaeve, J-M; Voyard, G; Bussière, P-O; Gardette, J-L

2011-04-21

The thermoporosimetry method was adapted to determine the mesh size distribution of an acrylate thermoset clearcoat. This goal was achieved by increasing the solvent rate transfer by increasing the pressure and temperature. A comparison of the results obtained using this approach with those obtained by DMA (dynamic mechanical analysis) underlined the accuracy of thermoporosimetry in characterizing the macromolecular architecture of thermosets. The thermoporosimetry method was also used to analyze the effects of photoaging on cross-linking, which result from the photodegradation of the acrylate thermoset. It was found that the formation of a three-dimensional network followed by densification generates a modification of the average mesh size that leads to a dramatic decrease of the meshes of the polymer.

Cadmium sulfide quantum dots/poly(acrylic acid-co-acrylic amide) composite hydrogel synthesized by gamma irradiation

NASA Astrophysics Data System (ADS)

Yang, Tao; Li, Qing; Wen, Wanxin; Hu, Liang; He, Weiwei; Liu, Hanzhou

2018-04-01

To improve the durability and stability of quantum dots (QDs) in the composite hydrogel, an irradiation induced reduction and polymerization-crosslinking method was reported herein where CdS QDs could be synthesized in situ and fastened to polymer chains due to the coordination forces between amino groups and CdS nanoparticles. The morphology and photoluminescence (PL) property of the composite hydrogel were studied. The result indicated that the CdS QDs with uniform size were dispersed evenly in the composite hydrogel, and the introduced CdS QDs had no obvious effect on the hydrogel structure. With the increases of reagent concentrations, PL intensity of the composite hydrogel was enhanced; however, the emission wavelength had no change.

Ca (OH)2Nanoparticles Based on Acrylic Copolymers for the consolidation and protection of Ancient Egypt Calcareous Stone Monuments

NASA Astrophysics Data System (ADS)

Al-Dosari, Mohammad A.; Darwish, Sawsan S.; Adam, Mahmoud A.; Elmarzugi, Nagib A.; Al-Mouallimi, Nadia; Ahmed, Sayed M.

2017-04-01

The deterioration of calcareous stones materials used in artistic/architectural field is one of the most serious problems facing conservation today. The aim of this study was to evaluate the effectiveness of nanosized particles of calcium hydroxide (slaked lime) as a consolidation and protection material dispersed in acrylic copolymer, poly ethylmethacrylate/methylacrylate (70:30) (Poly (EMA/MA), for calcareous stone monuments and painted surfaces affected by different kinds of decay. The synthesis process of Ca (OH)2 nanoparticles/polymer nanocomposites have been prepared by in situ emulsion polymerization system. The prepared nanocomposite containing 5% of Ca (OH)2 nanoparticles showed obvious transparency features and represent nanocomposites coating technology with hydrophobic, consolidating and well protection properties.

Photonic Shape Memory Polymer with Stable Multiple Colors

PubMed Central

2017-01-01

A photonic shape memory polymer film that shows large color response (∼155 nm) in a wide temperature range has been fabricated from a semi-interpenetrating network of a cholesteric polymer and poly(benzyl acrylate). The large color response is achieved by mechanical embossing of the photonic film above its broad glass transition temperature. The embossed film, as it recovers to its original shape on heating through the broad thermal transition, exhibits multiple structural colors ranging from blue to orange. The relaxation behavior of the embossed film can be fully described using a Kelvin–Voigt model, which reveals that the influence of temperature on the generation of colors is much stronger than that of time, thereby producing stable multiple colors. PMID:28840717

Nonlinear absorption enhancement of AuNPs based polymer nanocomposites

NASA Astrophysics Data System (ADS)

Zulina, Natalia A.; Baranov, Mikhail A.; Kniazev, Kirill I.; Kaliabin, Viacheslav O.; Denisyuk, Igor Yu.; Achor, Susan U.; Sitnikova, Vera E.

2018-07-01

Au nanoparticles (AuNPs) based polymer nanocomposites with high nonlinear absorption coefficient were synthesized by UV-photocuring. AuNPs were synthesized by laser ablation method in liquid monomer isodecyl acrylate (IDA). In this research, two colloids with 70 nm and 20 nm nanoparticles average sizes were studied. Size control was performed with SEM and STEM. Prepared nanomaterials exhibit strong third-order nonlinear optical responses under CW laser irradiation at 532 nm, which was estimated by using z-scan technique performed with open aperture. It was found experimentally that nonlinear absorption β is almost twice higher for nanocomposites with smaller AuNPs.

Hydrolyzable Poly[Poly(Ethylene Glycol) Methyl Ether Acrylate]-Colistin Prodrugs through Copper-Mediated Photoinduced Living Radical Polymerization.

PubMed

Zhu, Chongyu; Schneider, Elena K; Nikolaou, Vasiliki; Klein, Tobias; Li, Jian; Davis, Thomas P; Whittaker, Michael R; Wilson, Paul; Kempe, Kristian; Velkov, Tony; Haddleton, David M

2017-07-19

Through the recently developed copper-mediated photoinduced living radical polymerization (CP-LRP), a novel and well-defined polymeric prodrug of the antimicrobial lipopeptide colistin has been developed. A colistin initiator (Boc 5 -col-Br 2 ) was synthesized through the modification of colistin on both of its threonine residues using a cleavable initiator linker, 2-(2-bromo-2-methylpropanoyloxy) acetic acid (BMPAA), and used for the polymerization of acrylates via CP-LRP. Polymerization proceeds from both sites of the colistin initiator, and through the polymerization of poly(ethylene glycol) methyl ether acrylate (PEGA 480 ), three water-soluble polymer-colistin conjugates (col-PPEGA, having degrees of polymerization of 5, 10, and 20) were achieved with high yield (conversion of ≥93%) and narrow dispersities (Đ < 1.3) in 2-4 h. Little or no effect on the structure and activity of the colistin was observed during the synthesis, and most of the active colistin can be recovered from the conjugates in vitro within 2 days. Furthermore, in vitro biological analyses including disk diffusion, broth microdilution, and time-kill studies suggested that all of the conjugates have the ability to inhibit the growth of multidrug-resistant (MDR) Gram-negative bacteria, of which col-PPEGA DP5 and DP10 showed similar or better antibacterial performance compared to the clinically relevant colistin prodrug CMS, indicating their potential as an alternative antimicrobial therapy. Moreover, considering the control over the polymerization, the CP-LRP technique has the potential to provide an alternative platform for the development of polymer bioconjugates.

Silver distribution and release from an antimicrobial denture base resin containing silver colloidal nanoparticles.

PubMed

Monteiro, Douglas Roberto; Gorup, Luiz Fernando; Takamiya, Aline Satie; de Camargo, Emerson Rodrigues; Filho, Adhemar Colla Ruvolo; Barbosa, Debora Barros

2012-01-01

The aim of this study was to evaluate a denture base resin containing silver colloidal nanoparticles through morphological analysis to check the distribution and dispersion of these particles in the polymer and by testing the silver release in deionized water at different time periods. A Lucitone 550 denture resin was used, and silver nanoparticles were synthesized by reduction of silver nitrate with sodium citrate. The acrylic resin was prepared in accordance with the manufacturers' instructions, and silver nanoparticle suspension was added to the acrylic resin monomer in different concentrations (0.05, 0.5, and 5 vol% silver colloidal). Controls devoid of silver nanoparticles were included. The specimens were stored in deionized water at 37°C for 7, 15, 30, 60, and 120 days, and each solution was analyzed using atomic absorption spectroscopy. Silver was not detected in deionized water regardless of the silver nanoparticles added to the resin and of the storage period. Micrographs showed that with lower concentrations, the distribution of silver nanoparticles was reduced, whereas their dispersion was improved in the polymer. Moreover, after 120 days of storage, nanoparticles were mainly located on the surface of the nanocomposite specimens. Incorporation of silver nanoparticles in the acrylic resin was evidenced. Moreover, silver was not detected by the detection limit of the atomic absorption spectrophotometer used in this study, even after 120 days of storage in deionized water. Silver nanoparticles are incorporated in the PMMA denture resin to attain an effective antimicrobial material to help control common infections involving oral mucosal tissues in complete denture wearers. © 2011 by the American College of Prosthodontists.

Design and characterization of diclofenac diethylamine transdermal patch using silicone and acrylic adhesives combination.

PubMed

Panchaxari, Dandigi M; Pampana, Sowjanya; Pal, Tapas; Devabhaktuni, Bhavana; Aravapalli, Anil Kumar

2013-01-07

The objective of the study was to develop and characterize Diclofenac Diethylamine (DDEA) transdermal patch using Silicone and acrylic adhesives combination. Modified solvent evaporation method was employed for casting of film over Fluoropolymer coated polyester release liner. Initial studies included solubilization of drug in the polymers using solubilizers. The formulations with combination of adhesives were attempted to combine the desirable features of both the adhesives. The effect of the permeation enhancers on the drug permeation were studied using pig ear skin. All the optimized patches were subjected to adhesion, dissolution and stability studies. A 7-day skin irritancy test on albino rabbits and an in vivo anti-inflammatory study on wistar rats by carrageenan induced paw edema method were also performed. The results indicated the high percent drug permeation (% CDP-23.582) and low solubility nature (1%) of Silicone adhesive and high solubility (20%) and low% CDP (10.72%) of acrylic adhesive. The combination of adhesives showed desirable characteristics for DDEA permeation with adequate % CDP and sufficient solubility. Release profiles were found to be dependent on proportion of polymer and type of permeation enhancer. The anti-inflammatory study revealed the sustaining effect and high percentage inhibition of edema of C4/OLA (99.68%). The acute skin irritancy studies advocated the non-irritant nature of the adhesives used. It was concluded that an ideal of combination of adhesives would serve as the best choice, for fabrication of DDEA patches, for sustained effect of DDEA with better enhancement in permeation characteristics and robustness.

Design and characterization of diclofenac diethylamine transdermal patch using silicone and acrylic adhesives combination

PubMed Central

2013-01-01

Background and purpose of the study The objective of the study was to develop and characterize Diclofenac Diethylamine (DDEA) transdermal patch using Silicone and acrylic adhesives combination. Methods Modified solvent evaporation method was employed for casting of film over Fluoropolymer coated polyester release liner. Initial studies included solubilization of drug in the polymers using solubilizers. The formulations with combination of adhesives were attempted to combine the desirable features of both the adhesives. The effect of the permeation enhancers on the drug permeation were studied using pig ear skin. All the optimized patches were subjected to adhesion, dissolution and stability studies. A 7-day skin irritancy test on albino rabbits and an in vivo anti-inflammatory study on wistar rats by carrageenan induced paw edema method were also performed. Results The results indicated the high percent drug permeation (% CDP-23.582) and low solubility nature (1%) of Silicone adhesive and high solubility (20%) and low% CDP (10.72%) of acrylic adhesive. The combination of adhesives showed desirable characteristics for DDEA permeation with adequate % CDP and sufficient solubility. Release profiles were found to be dependent on proportion of polymer and type of permeation enhancer. The anti-inflammatory study revealed the sustaining effect and high percentage inhibition of edema of C4/OLA (99.68%). The acute skin irritancy studies advocated the non-irritant nature of the adhesives used. Conclusion It was concluded that an ideal of combination of adhesives would serve as the best choice, for fabrication of DDEA patches, for sustained effect of DDEA with better enhancement in permeation characteristics and robustness. PMID:23351568

Enzyme and Thermal Dual Responsive Amphiphilic Polymer Core-Shell Nanoparticle for Doxorubicin Delivery to Cancer Cells.

PubMed

Kashyap, Smita; Singh, Nitesh; Surnar, Bapurao; Jayakannan, Manickam

2016-01-11

Dual responsive polymer nanoscaffolds for administering anticancer drugs both at the tumor site and intracellular compartments are made for improving treatment in cancers. The present work reports the design and development of new thermo- and enzyme-responsive amphiphilic copolymer core-shell nanoparticles for doxorubicin delivery at extracellular and intracellular compartments, respectively. A hydrophobic acrylate monomer was tailor-made from 3-pentadecylphenol (PDP, a natural resource) and copolymerized with oligoethylene glycol acrylate (as a hydrophilic monomer) to make new classes of thermo and enzyme dual responsive polymeric amphiphiles. Both radical and reversible addition-fragmentation chain transfer (RAFT) methodologies were adapted for making the amphiphilic copolymers. These amphiphilic copolymers were self-assembled to produce spherical core-shell nanoparticles in water. Upon heating, the core-shell nanoparticles underwent segregation to produce larger sized aggregates above the lower critical solution temperature (LCST). The dual responsive polymer scaffold was found to be capable of loading water insoluble drug, such as doxorubicin (DOX), and fluorescent probe-like Nile Red. The drug release kinetics revealed that DOX was preserved in the core-shell assemblies at normal body temperature (below LCST, ≤ 37 °C). At closer to cancer tissue temperature (above LCST, ∼43 °C), the polymeric scaffold underwent burst release to deliver 90% of loaded drugs within 2 h. At the intracellular environment (pH 7.4, 37 °C) in the presence of esterase enzyme, the amphiphilic copolymer ruptured in a slow and controlled manner to release >95% of the drugs in 12 h. Thus, both burst release of cargo at the tumor microenvironment and control delivery at intracellular compartments were accomplished in a single polymer scaffold. Cytotoxicity assays of the nascent and DOX-loaded polymer were carried out in breast cancer (MCF-7) and cervical cancer (HeLa) cells. Among the two cell lines, the DOX-loaded polymers showed enhanced killing in breast cancer cells. Furthermore, the cellular uptake of the DOX was studied by confocal and fluorescence microscopes. The present investigation opens a new enzyme and thermal-responsive polymer scaffold approach for DOX delivery in cancer cells.

End-Functionalized Palladium SCS Pincer Polymers via Controlled Radical Polymerizations.

PubMed

Lye, Diane S; Cohen, Aaron E; Wong, Madeleine Z; Weck, Marcus

2017-07-01

A direct and facile route toward semitelechelic polymers, end-functionalized with palladated sulfur-carbon-sulfur pincer (Pd II -pincer) complexes is reported that avoids any post-polymerization step. Key to our methodology is the combination of reversible addition-fragmentation chain-transfer (RAFT) polymerization with functionalized chain-transfer agents. This strategy yields Pd end-group-functionalized materials with monomodal molar mass dispersities (Đ) of 1.18-1.44. The RAFT polymerization is investigated using a Pd II -pincer chain-transfer agent for three classes of monomers: styrene, tert-butyl acrylate, and N-isopropylacrylamide. The ensuing Pd II -pincer end-functionalized polymers are analyzed using 1 H NMR spectroscopy, gel-permeation chromatography, and elemental analysis. The RAFT polymerization methodology provides a direct pathway for the fabrication of Pd II -pincer functionalized polymers with complete end-group functionalization. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reversible clustering of pH- and temperature-responsive Janus magnetic nanoparticles.

PubMed

Isojima, Tatsushi; Lattuada, Marco; Vander Sande, John B; Hatton, T Alan

2008-09-23

Janus nanoparticles have been synthesized consisting of approximately 5 nm magnetite nanoparticles coated on one side with a pH-dependent and temperature-independent polymer (poly(acrylic acid), PAA), and functionalized on the other side by a second (tail) polymer that is either a pH-independent polymer (polystyrene sodium sulfonate, PSSNa) or a temperature-dependent polymer (poly(N-isopropyl acrylamide), PNIPAM). These Janus nanoparticles are dispersed stably as individual particles at high pH values and low temperatures, but can self-assemble at low pH values (PSSNa) or at high temperatures (>31 degrees C) (PNIPAM) to form stable dispersions of clusters of approximately 80-100 nm in hydrodynamic diameter. The Janus nanoparticle compositions were verified using FTIR and XPS, and their structures observed directly by TEM. Their clustering behavior is analyzed by dynamic light scattering and zeta potential measurements.

In Situ Infrared Ellipsometry for Protein Adsorption Studies on Ultrathin Smart Polymer Brushes in Aqueous Environment

DOE PAGES

Kroning, Annika; Furchner, Andreas; Aulich, Dennis; ...

2015-02-10

The protein-adsorbing and -repelling properties of various smart nanometer-thin polymer brushes with high potential for biosensing and biomedical applications are studied by in-situ infrared-spectroscopic ellipsometry (IRSE). IRSE as a highly sensitive non-destructive technique allows us to investigate protein adsorption on polymer brushes in aqueous environment in dependence of external stimuli like temperature and pH. These stimuli are, for instance, relevant in switchable mixed brushes containing poly(N-isopropyl acrylamide) and poly(acrylic acid), respectively. We use such brushes as model surfaces for controlling protein adsorption of human serum albumin and human fibrinogen. IRSE can distinguish between polymer-specific vibrational bands, which yield insights intomore » the hydration state of the brushes, and changes in the protein-specific amide bands, which are related to changes of the protein secondary structure.« less

In situ measurement of Larval Salamander growth using individuals marked with acrylic polymers

Treesearch

Brent R. Johnson; J. Bruce Wallace

2002-01-01

Mark-recapture studies are often used to provide valuable life history information for animal populations. However, long-term marking of larval amphibians has been problematic because of their small size, delicate skin, and ability to regenerate tissues (Cecil and Just 1978; Donnelly et al. 1994; Seale and Boraas 1974). Procedures that have been used to mark larvae...

COMPARISON AND EVALUATION OF THE SYNTHETIC BIOPOLYMER POLY-L-ASPARTIC ACID AND THE SYNTHETIC "PLASTIC" POLYMER POLY-ACRYLIC ACID FOR USE IN METAL ION-EXCHANGE SYSTEMS. (R826694C651)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Compacted Multiparticulate Systems for Colon-Specific Delivery of Ketoprofen.

PubMed

de Alencar, Rodrigo Gomes; de Oliveira, Aline Carlos; Lima, Eliana Martins; da Cunha-Filho, Marcílio Sérgio Soares; Taveira, Stephânia Fleury; Marreto, Ricardo Neves

2017-08-01

Pellet-containing tablets for colon-specific drug delivery present higher targeting efficiency and lower costs when compared with monolithic tablets and pellet-filled capsules, respectively. In this study, pellets containing ketoprofen were coated with different acrylic polymers and submitted to compaction. The influence of formulation and process factors on film integrity was then evaluated. Pellets were prepared via extrusion-spheronization and coated using two acrylic polymers (Eudragit® FS 30 D and Opadry® 94 k28327, PMMA and PMA, respectively). The resulting pellets were mixed with placebo granules and compressed in a hydraulic press. Multiple regression showed that ketoprofen release from pellet-containing tablets is predominantly influenced by pellet content, hardness, friability, and disintegration time. PMA-containing tablets prepared under low compaction force or with low pellet content showed rapid disintegration (<1 min) and ketoprofen release similar to those of uncompressed coated pellets (∼30% at 360 min of experiment). On the other hand, PMMA-containing tablets showed a higher rupture level, and those prepared with higher pellet content gave rise to a non-disintegrating matrix. Coated pellets were shown to be able to target ketoprofen to the colonic region. Targeting capacity was dependent on the physicochemical characteristics of the tablets.

Frequency-Dependent Magnetic Susceptibility of Magnetite and Cobalt Ferrite Nanoparticles Embedded in PAA Hydrogel

PubMed Central

van Berkum, Susanne; Dee, Joris T.; Philipse, Albert P.; Erné, Ben H.

2013-01-01

Chemically responsive hydrogels with embedded magnetic nanoparticles are of interest for biosensors that magnetically detect chemical changes. A crucial point is the irreversible linkage of nanoparticles to the hydrogel network, preventing loss of nanoparticles upon repeated swelling and shrinking of the gel. Here, acrylic acid monomers are adsorbed onto ferrite nanoparticles, which subsequently participate in polymerization during synthesis of poly(acrylic acid)-based hydrogels (PAA). To demonstrate the fixation of the nanoparticles to the polymer, our original approach is to measure low-field AC magnetic susceptibility spectra in the 0.1 Hz to 1 MHz range. In the hydrogel, the magnetization dynamics of small iron oxide nanoparticles are comparable to those of the particles dispersed in a liquid, due to fast Néel relaxation inside the particles; this renders the ferrogel useful for chemical sensing at frequencies of several kHz. However, ferrogels holding thermally blocked iron oxide or cobalt ferrite nanoparticles show significant decrease of the magnetic susceptibility resulting from a frozen magnetic structure. This confirms that the nanoparticles are unable to rotate thermally inside the hydrogel, in agreement with their irreversible fixation to the polymer network. PMID:23673482

Rapid synthesis of graft copolymers from natural cellulose fibers.

PubMed

Thakur, Vijay Kumar; Thakur, Manju Kumari; Gupta, Raju Kumar

2013-10-15

Cellulose is the most abundant natural polysaccharide polymer, which is used as such or its derivatives in a number of advanced applications, such as in paper, packaging, biosorption, and biomedical. In present communication, in an effort to develop a proficient way to rapidly synthesize poly(methyl acrylate)-graft-cellulose (PMA-g-cellulose) copolymers, rapid graft copolymerization synthesis was carried out under microwave conditions using ferrous ammonium sulfate-potassium per sulfate (FAS-KPS) as redox initiator. Different reaction parameters such as microwave radiation power, ratio of monomer, solvent and initiator concentrations were optimized to get the highest percentage of grafting. Grafting percentage was found to increase with increase in microwave power up to 70%, and maximum 36.73% grafting was obtained after optimization of all parameters. Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG) analysis were used to confirm the graft copolymerization of poly(methyl acrylate) (PMA) onto the mercerized cellulose. The grafted cellulosic polymers were subsequently subjected to the evaluation of different physico-chemical properties in order to access their application in everyday life, in a direction toward green environment. The grafted copolymers demonstrated increased chemical resistance, and higher thermal stability. Published by Elsevier Ltd.

Starch derivative-based superabsorbent with integration of water-retaining and controlled-release fertilizers.

PubMed

Zhong, Kang; Lin, Zuan-Tao; Zheng, Xi-Liang; Jiang, Gang-Biao; Fang, Yu-Sheng; Mao, Xiao-Yun; Liao, Zong-Wen

2013-02-15

Phosphate rock (PHR), a traditional fertilizer, is abundant, but is hard to be utilized by plants. To improve the utilization of PHR, and to integrate water-retaining and controlled-release fertilizers, an agricultural superabsorbent polymer based on sulfonated corn starch/poly (acrylic acid) embedding phosphate rock (SCS/PAA/PHR) was prepared. PHR can be suspended and well-dispersed in SCS/PAA by sulfonated corn starch (SCS). PHR and KOH were mixed in acrylic acid solution to provide phosphorus (P) and potassium (K) nutrients, respectively. Impacts on water absorption capacity of the superabsorbent were investigated. The maximum swelling capacity in distilled water or 0.9 wt.% (weight percent) NaCl solution reached 498 g g(-1) and 65 g g(-1) (water/prepared dry superabsorbent) respectively. Moreover, release behaviours of P and K in SCS/PAA/PHR were also investigated. The results showed that SCS/PAA/PHR possessed excellent sustained-release property of plant nutrient, and the SCS/PAA could improve the P release greatly. Besides, the XPS analysis was employed to study the relationship between PHR and superabsorbent polymer. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development and characterization of high refractive index and high scattering acrylate polymer layers

NASA Astrophysics Data System (ADS)

Eiselt, Thomas; Gomard, Guillaume; Preinfalk, Jan; Gleissner, Uwe; Lemmer, Uli; Hanemann, Thomas

2016-04-01

The aim is to develop a polymer layer which has the ability to diffuse light homogeneously and exhibit a high refractive index. The mixtures are containing an acrylate casting resin, benzylmethacrylate, phenanthrene and other additives. Phenanthrene is employed to increase the refractive index. The mixtures are first rheologically characterized and then polymerized with heat and UV radiation. For the refractive index measurements the polymerized samples require a planar surface without air bubbles. To produce flat samples a special construction consisting of a glass plate, a teflon sheet, a silicone ring (PDMS mold), another teflon sheet and another glass plate is developed. Glue clamps are used to fix this construction together. Selected samples have a refractive index of 1.585 at 20°C at a wavelength of 589nm. A master mixture with a high refractive index is taken for further experiments. Nano scaled titanium dioxide is added and dispersed into the master mixture and then spin coated on a glass substrate. These layers are optically characterized. The specular transmission and the overall transmission are measured to investigate the degree of scattering, which is defined as the haze. Most of the presented layers express the expected haze of over 50%.

Chitosan-Acrylic Polymeric Nanoparticles with Dynamic Covalent Bonds. Synthesis and Stimuli Behavior.

PubMed

Palacio, Herman; Otálvaro, Felipe; Giraldo, Luis Fernando; Ponchel, Gilles; Segura-Sánchez, Freimar

2017-12-01

Drug delivery represents one of the most important research fields within the pharmaceutical industry. Different strategies are reported every day in a dynamic search for carriers with the ability to transport drugs across the body, avoiding or decreasing toxic issues and improving therapeutic activity. One of the most interesting strategies currently under research is the development of drug delivery systems sensitive to different stimuli, due to the high potential attributed to the selective delivery of the payload. In this work, a stimuli-sensitive nanocarrier was built with a bifunctional acrylic polymer, linked by imine and disulfide bonds to thiolate chitosan, the latter being a biopolymer widely known in the field of tissue engineering and drug delivery by its biodegradability and biocompatibility. These polymer nanoparticles were exposed to different changes in pH and redox potential, which are environments commonly found inside cancer cells. The results proof the ability of the nanoparticles to keep the original structure when either changes in pH or redox potential were applied individually. However, when both stimuli were applied simultaneously, a disassembly of the nanoparticles was evident. These special characteristics make these nanoparticles suitable nanocarriers with potential for the selective delivery of anticancer drugs.

Preparation of porous carbons from polymeric precursors modified with acrylated kraft lignin

NASA Astrophysics Data System (ADS)

Sobiesiak, M.

2016-04-01

The presented studies concern the preparation of porous carbons from a BPA.DA-St polymer containing acrylated kraft lignin as a monomer. The porous polymeric precursor in the form of microspheres was synthesized in suspension polymerization process. Next samples of the polymer were impregnated with acetic acid or aqueous solution of acetates (potassium or ammonia), dried and carbonised in nitrogen atmosphere at 450°C. After carbonization microspherical shape of the materials was remained, that is desired feature for potential application in chromatography or SPE technique. Chemical and textural properties of the porous carbon adsorbents were characterized using infrared spectroscopy (ATR-FTIR), thermogravimetry analyses with mass spectrometry of released gases (TG-MS) and nitrogen sorption experiments. The presented studies revealed the impregnation is useful method for development of porous structure of carbonaceous materials. The highest values of porous structure parameters were obtained when acetic acid and ammonium acetate were used as impregnating substances. On the surface of the materials oxygen functional groups are present that is important for specific interactions during sorption processes. The highest contents of functionalities were observed for carbon BPA.DA-St-LA-C-AcNH4.

Thiolated polymers: evaluation of the influence of the amount of covalently attached L-cysteine to poly(acrylic acid).

PubMed

Palmberger, Thomas F; Albrecht, Karin; Loretz, Brigitta; Bernkop-Schnürch, Andreas

2007-06-01

It was the aim of this study to investigate the influence of the amount of thiol groups being covalently attached to poly(acrylic acid) 450 kDa on its properties. Five different PAA(450)-L-cysteine conjugates (PAA(450)-Cys) were synthesized bearing 53.0 (PAA I), 113.4 (PAA II), 288.8 (PAA III), 549.1 (PAA IV) and 767.0 (PAA V) micromol immobilized thiol groups per gram polymer. Mucoadhesion studies utilizing the rotating cylinder method, tensile studies and disintegration studies were performed. Self-crosslinking properties were measured by the increase in viscosity. Permeation studies were performed on rat small intestine and Caco-2 monolayers using sodium fluorescein as model drug. Following residence times on the rotating cylinder could be identified: PAA I 3.1; PAA II 5.2; PAA III 22.0; PAA IV 33.8; PAA V 53.7; control 1.3 [h]. The disintegration time of all PAA(450)-Cys tablets was strongly dependent on the degree of thiolation of the polymer. Self-crosslinking studies showed that the different PAA(450)-Cys conjugates (3% m/v) in phosphate buffer, pH 6.8, formed intramolecular disulfide bonds. In case of Caco-2 monolayer transport studies following P(app)-values could be identified: PAA I 9.8; PAA II 10.1; PAA III 11.1; PAA IV 8.9; PAA V 8.2; control 6.4 [P(app)x10(-6), cms(-1)]. Mucoadhesive and self-crosslinking properties are strongly dependent on the degree of thiolation of the polymer and with respect to transport studies, an optimum amount of covalently attached L-cysteine could be identified.

Surface radical chain-transfer reaction in deep eutectic solvents for preparation of silica-grafted stationary phases in hydrophilic interaction chromatography.

PubMed

Yang, Beibei; Cai, Tianpei; Li, Zhan; Guan, Ming; Qiu, Hongdeng

2017-12-01

In this paper, deep eutectic solvents (DESs) were firstly used as new and green solvents for the preparation of polymer-grafted silica stationary phases. 1-Vinylimidazole and acrylic acid were homopolymerized and copolymerized on silica via surface radical chain-transfer reaction in the DESs. Three stationary phases including poly(1-vinylimidazole)-, poly(acrylic acid)-, poly(1-vinylimidazole-co-acrylic acid)-grafted silica were obtained and characterized by elemental analysis and Fourier transform infrared spectroscopy. Their hydrophilic interaction chromatographic properties were investigated for separation of nucleosides, nucleobases, saccharides and amino acids. The retention changes of nucleosides and nucleobases on these columns were investigated under different chromatographic conditions including acetonitrile content, salt concentration, pH of mobile phase and column temperature. The repeatability of these columns was also investigated. The results demonstrate that DESs can be used as new media for the synthesis of silica-based stationary phases by homopolymerization and copolymerization on the surface of porous silica particles. Copyright © 2017 Elsevier B.V. All rights reserved.

Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

NASA Astrophysics Data System (ADS)

Barleany, Dhena Ria; Ulfiyani, Fida; Istiqomah, Shafina; Heriyanto, Heri; Rahmayetty, Erizal

2015-12-01

Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w-1 acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g-1 of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g-1 and 523 g g-1 for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).

Synthesis of wheat straw cellulose-g-poly (potassium acrylate)/PVA semi-IPNs superabsorbent resin.

PubMed

Liu, Jia; Li, Qian; Su, Yuan; Yue, Qinyan; Gao, Baoyu; Wang, Rui

2013-04-15

To better use wheat straw and minimize its negative impact on environment, a novel semi-interpenetrating polymer networks (semi-IPNs) superabsorbent resin (SAR) composed of wheat straw cellulose-g-poly (potassium acrylate) (WSC-g-PKA) network and linear polyvinyl alcohol (PVA) was prepared by polymerization in the presence of a redox initiating system. The structure and morphology of semi-IPNs SAR were characterized by means of FTIR, SEM and TGA, which confirmed that WSC and PVA participated in the graft polymerization reaction with acrylic acid (AA). The factors that can influence the water absorption of the semi-IPNs SAR were investigated and optimized, including the weight ratios of AA to WSC and PVA to WSC, the content of initiator and crosslinker, neutralization degree (ND) of AA, reaction temperature and time. The semi-IPNs SAR prepared under optimized synthesis condition gave the best water absorption of 266.82 g/g in distilled water and 34.32 g/g in 0.9 wt% NaCl solution. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of silicate module of water glass on rheological parameters of poly(sodium acrylate)/sodium silicate hydrogels

NASA Astrophysics Data System (ADS)

Mastalska-Popiawska, J.; Izak, P.

2017-01-01

The poly(sodium acrylate)/sodium silicate hydrogels were synthesized in the presence of sodium thiosulphate and potassium persulphate as the redox initiators and N,N’-methylene-bisacrylamide as the cross-linking monomer. 20 wt% aqueous solution of sodium acrylate was polymerized together with water glass with different silicate modules (M) from 1.74 to 2.29, in three mass ratio of the monomer solution to the water glass 2:1, 1:1 and 1:2. Such obtained hybrid composites were rheologically tested using the oscillation method. It allowed to designate the crossover point during polymerization, as well as to define the viscoelastic properties of the casted hydrogel samples one week after the reaction. The obtained results of the oscillation measurements showed that cross-linking reaction proceeds very quickly and the lower the silicate module is, the process starts faster. After the completion of the reaction the silicate-polymer hydrogels are strongly elastic materials and the highest elasticity characterizes systems with the mass ratio 1:2, i.e. with the highest water glass content.

Preparation of Caco-2 cell sheets using plasma polymerised acrylic acid as a weak boundary layer.

PubMed

Majani, Ruby; Zelzer, Mischa; Gadegaard, Nikolaj; Rose, Felicity R; Alexander, Morgan R

2010-09-01

The use of cell sheets for tissue engineering applications has considerable advantages over single cell seeding techniques. So far, only thermoresponsive surfaces have been used to manufacture cell sheets without chemically disrupting the cell-surface interactions. Here, we present a new and facile technique to prepare sheets of epithelial cells using plasma polymerised acrylic acid films. The cell sheets are harvested by gentle agitation of the media without the need of any additional external stimulus. We demonstrate that the plasma polymer deposition conditions affect the viability and metabolic activity of the cells in the sheet and relate these effects to the different surface properties of the plasma polymerised acrylic acid films. Based on surface analysis data, a first attempt is made to explain the mechanism behind the cell sheet formation. The advantage of the epithelial cell sheets generated here over single cell suspensions to seed a PLGA scaffold is presented. The scaffold itself, prepared using a mould fabricated via photolithography, exhibits a unique architecture that mimics closely the dimensions of the native tissue (mouse intestine). Copyright 2010 Elsevier Ltd. All rights reserved.

Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

PubMed Central

Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

2016-01-01

The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA. PMID:26786315

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Hui; Wei, Yang; Wang, Cheng

The excessive volume changes during cell cycling of Si-based anode in lithium ion batteries impeded its application. One major reason for the cell failure is particle isolation during volume shrinkage in delithiation process, which makes strong adhesion between polymer binder and anode active material particles a highly desirable property. Here, a biomimetic side-chain conductive polymer incorporating catechol, a key adhesive component of the mussel holdfast protein, was synthesized. Atomic force microscopy-based single-molecule force measurements of mussel-inspired conductive polymer binder contacting a silica surface revealed a similar adhesion toward substrate when compared with an effective Si anode binder, homo-poly(acrylic acid), withmore » the added benefit of being electronically conductive. Electrochemical experiments showed a very stable cycling of Si-alloy anodes realized via this biomimetic conducting polymer binder, leading to a high loading Si anode with a good rate performance. We attribute the ability of the Si-based anode to tolerate the volume changes during cycling to the excellent mechanical integrity afforded by the strong interfacial adhesion of the biomimetic conducting polymer.« less

Polymerization speed and diffractive experiments in polymer network LC test cells

NASA Astrophysics Data System (ADS)

Braun, Larissa; Gong, Zhen; Habibpourmoghadam, Atefeh; Schafforz, Samuel L.; Wolfram, Lukas; Lorenz, Alexander

2018-02-01

Polymer-network liquid crystals (LCs), where the response properties of a LC can be enhanced by the presence of a porous polymer network, are investigated. In the reported experiments, liquid crystals were doped with a small amount (< 10%) of photo-curable acrylate monomers. Samples with surface grafted photoinitiators, dissolvable photoinitiators, and samples with both kinds of photoinitiators were prepared. Both conventional (planar electrodes) and diffractive (interdigitated electrodes) test cells were used. These samples were exposed with a UV light source and changes of their capacitance were investigated with an LCR meter during exposure. Due to the presence of the in-situ generated polymer network, the electro-optic response properties of photo cured samples were enhanced. For example, their continuous phase modulation properties led to more localized responses in samples with interdigitated electrodes, which caused suppression of selected diffraction orders in the diffraction patterns recorded in polymer network LC samples. Moreover, capacitance changes were investigated during photopolymerization of a blue phase LC.

Glycosylated polyacrylate nanoparticles by emulsion polymerization

PubMed Central

Abeylath, Sampath C.; Turos, Edward

2007-01-01

A selection of glycosylated polyacrylate nanoparticles has been prepared by radical-initiated emulsion polymerization in aqueous media. Using ethyl acrylate as a co-monomer, carbohydrate acrylates were incorporated into the poly(ethyl acrylate) framework to give stable emulsions of glyconanoparticles with an average particle size of around 40 nm. Using this technique a variety of glyconanoparticles were prepared from 3-O-acryloyl-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, 1-O-acryloyl-2,3:5,6-di-O-isopropylidene-α-D-mannofuranose, 6-O-acryloyl-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose, 2-N-acryloyl-1,3,4,6-tetra-O-acetyl-β-D-glucosamine, 5-O-acryloyl-2,3-isopropylidene-1-methoxy-β-D-ribofuranose and 4-N-acetyl-5’-O-acryloyl-2’,3’-O-isopropylidene cytidine. Scanning electron microscopy, dynamic light scattering and proton NMR analysis of the emulsions indicated essentially 100% incorporation of the carbohydrate acrylate monomer into the polymer with the exception of O-benzyl- and O-benzoyl-protected carbohydrate acrylates, which gave incomplete incorporation. Formation of larger glyconanoparticles of ~80nm with (unprotected) 3-O-acryloyl-D-glucose and 5-O-acryloyl-1-methoxy-β-D-ribofuranose revealed the influence of free hydroxyl groups in the monomer on the particle size during polymerization, a feature which is also apparently dependent on the amount of carbohydrate in the matrix. This methodology allows for a new, simple route to the synthesis of polymeric glyconanoparticles with potential applications in targeted drug delivery and materials development. PMID:18677404

Radiation-induced synthesis of poly(acrylic acid) nanogels

NASA Astrophysics Data System (ADS)

Matusiak, Malgorzata; Kadlubowski, Slawomir; Ulanski, Piotr

2018-01-01

Nanogel is a two-component system of a diameter in the range of tens of nanometers, consisting of an intramolecularly crosslinked polymer chain and solvent, typically water, filling the space between segments of the macromolecule. Microgels are bigger than nanogels and their size range is between 100 nm to 100 μm. One of the methods used for synthesizing nanogels is linking the segments of a single macromolecule with the use of ionizing radiation, by intramolecular recombination of radiation-generated polymer radicals. The main advantage of this technique is absence of monomers, catalysts, surfactants or crosslinking agents. This method is an interesting alternative way of synthesizing polymeric carriers for biomedical applications. The aim of the study was radiation synthesis and characterization of poly(acrylic acid) - PAA - nanogels and microgels. The physico-chemical properties were described by determination of weight-average molecular weight and dimensions (radius of gyration, hydrodynamic radius) of the nanogels and microgels. Influence of polymer concentration and dose on these parameters was analyzed. Adjusting the PAA concentration and absorbed dose, one can control the molecular weight and dimensions of nanogels. The solutions of PAA were irradiated with two sources of ionizing radiation: γ-source and electron accelerator. The former method yields mainly microgels due to prevailing intermolecular crosslinking, while the latter promotes intramolecular recombination of PAA-derived radicals and in consequence formation of nanogels. In the future radiation-synthesized PAA nanogels, after functionalization, will be tested as carriers for delivering radionuclides to the tumor cells.

Designing a Novel Polymer Electrolyte for Improving the Electrode/Electrolyte Interface in Flexible All-Solid-State Electrical Double-Layer Capacitors.

PubMed

Wang, Jeng-An; Lu, Yi-Ting; Lin, Sheng-Chi; Wang, Yu-Sheng; Ma, Chen-Chi M; Hu, Chi-Chang

2018-05-30

A novel copolymer, polyurethane-poly(acrylic acid) (PAA), is successfully synthesized from poly(acrylic acid) (PAA) backbone cross-linked with waterborne polyurethane (WPU). This sticky polymer, which is neutralized with 1 M KOH and then soaked in 1 M KOH (denoted as WPU-PAAK-K), provides an ionic conductivity greater than 10 -2 S cm -1 and acts as a gel electrolyte perfectly improving the electrode/electrolyte interfaces in a flexible all-solid-state electrical double-layer capacitor (EDLC). The PAA backbone chains in the copolymer increase the amount of carboxyl groups and promote the segmental motion. The carboxyl groups enhance the water-uptake capacity, which facilitates the ion transport and promotes the ionic conductivity. The cross-linked agent, WPU chains, effectively maintains the rich water content and provides mechanical stickiness to bind two electrodes together. An acid-treated carbon paper (denoted as ACP) combining with such a gel polymer electrolyte demonstrates excellent capacitive behavior with a high areal capacitance of 211.6 mF cm -2 at 10 mV s -1 . A full cell consisting of ACP/WPU-PAAK-K/ACP displays a low equivalent series resistance of 0.44 Ω from the electrochemical impedance spectroscopic results. An all-solid-state ACP/WPU-PAAK-K/ACP EDLC provides an areal specific capacitance of 94.6 mF cm -2 at 1 mA cm -2 . This device under 180° bending shows a capacitance retention over 90%, revealing its remarkable flexibility.

Constructing honeycomb micropatterns on nonplanar substrates with high glass transition temperature polymers.

PubMed

Ding, Jianyun; Gong, Jianliang; Bai, Hua; Li, Lei; Zhong, Yawen; Ma, Zhi; Svrcek, Vladimir

2012-08-15

In Qiao's previous report, only star polymers with T(g) (glass transition temperature) below 48°C were found forming homogeneous honeycomb coatings on the nonplanar substrates. The polymers with high T(g) are believed not able to duplicate nonplanar substrate due to their brittleness. This article presents a comprehensive study on the construction of macroporous polymeric films on various nonplanar substrates with static breath figure (BF) technique, using linear polymers with high T(g). Two kinds of linear polymers with high T(g), polystyrene-b-poly(acrylic acid) and polystyrene without polar end groups, are employed to prepare 3-dimensional macroporous films on different nonplanar substrates. Scanning electronic microscopy views on the side wall in addition to views in-plane prove that polymer films with BF array perfectly replicated the surface features of these substrates. The formation processes of macropores on these substrates are analyzed in detail, and it demonstrates that neither molecular topography nor T(g) of polymers is the critical factor contouring nonplanar substrate. A new hypothesis involving polymer plasticization and conformation during the solvent evaporation is formulated. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

Photo-triggered solvent-free metamorphosis of polymeric materials.

PubMed

Honda, Satoshi; Toyota, Taro

2017-09-11

Liquefaction and solidification of materials are the most fundamental changes observed during thermal phase transitions, yet the design of organic and polymeric soft materials showing isothermal reversible liquid-nonliquid conversion remains challenging. Here, we demonstrate that solvent-free repeatable molecular architectural transformation between liquid-star and nonliquid-network polymers that relies on cleavage and reformation of a covalent bond in hexaarylbiimidazole. Liquid four-armed star-shaped poly(n-butyl acrylate) and poly(dimethyl siloxane) with 2,4,5-triphenylimidazole end groups were first synthesized. Subsequent oxidation of the 2,4,5-triphenylimidazoles into 2,4,5-triphenylimidazoryl radicals and their coupling with these liquid star polymers to form hexaarylbiimidazoles afforded the corresponding nonliquid network polymers. The resulting nonliquid network polymers liquefied upon UV irradiation and produced liquid star-shaped polymers with 2,4,5-triphenylimidazoryl radical end groups that reverted to nonliquid network polymers again by recoupling of the generated 2,4,5-triphenylimidazoryl radicals immediately after terminating UV irradiation.The design of organic and polymeric soft materials showing isothermal reversible liquid-nonliquid conversion is challenging. Here, the authors show solvent-free repeatable molecular architectural transformation between liquid-star and non-liquid-network polymers by the cleavage and reformation of covalent bonds in the polymer chain.

Hybrid capacitor with activated carbon electrode, Ni(OH) 2 electrode and polymer hydrogel electrolyte

NASA Astrophysics Data System (ADS)

Nohara, Shinji; Asahina, Toshihide; Wada, Hajime; Furukawa, Naoji; Inoue, Hiroshi; Sugoh, Nozomu; Iwasaki, Hideharu; Iwakura, Chiaki

A new hybrid capacitor (HC) cell was assembled using an activated carbon (AC) negative electrode, an Ni(OH) 2 positive electrode and a polymer hydrogel electrolyte prepared from crosslinked potassium poly(acrylate) (PAAK) and KOH aqueous solution. The HC cell was characterized compared with an electric double layer capacitor (EDLC) using two AC electrodes and the polymer hydrogel electrolyte. It was found that the HC cell successfully worked in the larger voltage range and exhibited ca. 2.4 times higher capacitance than the EDLC cell. High-rate dischargeability of the HC cell was also superior to that of the EDLC cell. These improved characteristics strongly suggest that the HC cell can be a promising system of capacitors with high energy and power densities.

Redox-responsive self-healing materials formed from host–guest polymers

PubMed Central

Nakahata, Masaki; Takashima, Yoshinori; Yamaguchi, Hiroyasu; Harada, Akira

2011-01-01

Expanding the useful lifespan of materials is becoming highly desirable, and self-healing and self-repairing materials may become valuable commodities. The formation of supramolecular materials through host–guest interactions is a powerful method to create non-conventional materials. Here we report the formation of supramolecular hydrogels and their redox-responsive and self-healing properties due to host–guest interactions. We employ cyclodextrin (CD) as a host molecule because it is environmentally benign and has diverse applications. A transparent supramolecular hydrogel quickly forms upon mixing poly(acrylic acid) (pAA) possessing β-CD as a host polymer with pAA possessing ferrocene as a guest polymer. Redox stimuli induce a sol−gel phase transition in the supramolecular hydrogel and can control self-healing properties such as re-adhesion between cut surfaces. PMID:22027591

Immobilization of Polyoxometalates on Tailored Polymeric Surfaces.

PubMed

Aguado-Ureta, Saioa; Rodríguez-Hernández, Juan; Del Campo, Adolfo; Perez-Álvarez, Leyre; Ruiz-Rubio, Leire; Vilas, José Luis; Artetxe, Beñat; Reinoso, Santiago; Gutiérrez-Zorrilla, Juan M

2018-03-02

Herein we describe the preparation of hybrid polymer-inorganic interfaces by the immobilization of polyoxometalate nanoclusters on functionalized polymer surfaces. The polymeric surfaces were made of polystyrene- b -poly(acrylic acid)/polystyrene (PS- b -PAA/PS) blends by spin coating on a silicon wafer. The functionalization of the polymer film was obtained by interfacial migration of the amphiphilic block copolymer toward the interface upon water vapor annealing. The carboxylic acid functional groups contained in the PAA block were then employed to anchor the [Ln III (α-SiW 11 O 39 )] 5- polyoxometalates (Ln: Ce, Er). This purpose was achieved by immersing the films in aqueous solutions of the in situ-formed inorganic nanoclusters. X-ray photoelectron and confocal Raman spectroscopies, together with atomic force microscopy, confirmed the immobilization of the inorganic species at the interface.

Method for dialysis on microchips using thin porous polymer membrane

DOEpatents

Singh, Anup K [San Francisco, CA; Kirby, Brian J [San Francisco, CA; Shepodd, Timothy J [Livermore, CA

2009-05-19

Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

Dialysis on microchips using thin porous polymer membranes

DOEpatents

Singh, Anup K.; Kirby, Brian J.; Shepodd, Timothy J.

2007-09-04

Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and form a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

Mussel-Inspired Conductive Polymer Binder for Si-Alloy Anode in Lithium-Ion Batteries

DOE PAGES

Zhao, Hui; Wei, Yang; Wang, Cheng; ...

2018-01-15

The excessive volume changes during cell cycling of Si-based anode in lithium ion batteries impeded its application. One major reason for the cell failure is particle isolation during volume shrinkage in delithiation process, which makes strong adhesion between polymer binder and anode active material particles a highly desirable property. Here, a biomimetic side-chain conductive polymer incorporating catechol, a key adhesive component of the mussel holdfast protein, was synthesized. Atomic force microscopy-based single-molecule force measurements of mussel-inspired conductive polymer binder contacting a silica surface revealed a similar adhesion toward substrate when compared with an effective Si anode binder, homo-poly(acrylic acid), withmore » the added benefit of being electronically conductive. Electrochemical experiments showed a very stable cycling of Si-alloy anodes realized via this biomimetic conducting polymer binder, leading to a high loading Si anode with a good rate performance. We attribute the ability of the Si-based anode to tolerate the volume changes during cycling to the excellent mechanical integrity afforded by the strong interfacial adhesion of the biomimetic conducting polymer.« less

Three-Dimensional Flexible Electronics Enabled by Shape Memory Polymer Substrates for Responsive Neural Interfaces.

PubMed

Ware, Taylor; Simon, Dustin; Hearon, Keith; Liu, Clive; Shah, Sagar; Reeder, Jonathan; Khodaparast, Navid; Kilgard, Michael P; Maitland, Duncan J; Rennaker, Robert L; Voit, Walter E

2012-12-01

Planar electronics processing methods have enabled neural interfaces to become more precise and deliver more information. However, this processing paradigm is inherently 2D and rigid. The resulting mechanical and geometrical mismatch at the biotic-abiotic interface can elicit an immune response that prevents effective stimulation. In this work, a thiol-ene/acrylate shape memory polymer is utilized to create 3D softening substrates for stimulation electrodes. This substrate system is shown to soften in vivo from more than 600 to 6 MPa. A nerve cuff electrode that coils around the vagus nerve in a rat and that drives neural activity is demonstrated.

Integrated carbon fiber electrodes within hollow polymer microneedles for transdermal electrochemical sensing

PubMed Central

Miller, Philip R.; Gittard, Shaun D.; Edwards, Thayne L.; Lopez, DeAnna M.; Xiao, Xiaoyin; Wheeler, David R.; Monteiro-Riviere, Nancy A.; Brozik, Susan M.; Polsky, Ronen; Narayan, Roger J.

2011-01-01

In this study, carbon fiber electrodes were incorporated within a hollow microneedle array, which was fabricated using a digital micromirror device-based stereolithography instrument. Cell proliferation on the acrylate-based polymer used in microneedle fabrication was examined with human dermal fibroblasts and neonatal human epidermal keratinocytes. Studies involving full-thickness cadaveric porcine skin and trypan blue dye demonstrated that the hollow microneedles remained intact after puncturing the outermost layer of cadaveric porcine skin. The carbon fibers underwent chemical modification in order to enable detection of hydrogen peroxide and ascorbic acid; electrochemical measurements were demonstrated using integrated electrode-hollow microneedle devices. PMID:21522504

Photonic porous silicon as a pH sensor.

PubMed

Pace, Stephanie; Vasani, Roshan B; Zhao, Wei; Perrier, Sébastien; Voelcker, Nicolas H

2014-01-01

Chronic wounds do not heal within 3 months, and during the lengthy healing process, the wound is invariably exposed to bacteria, which can colonize the wound bed and form biofilms. This alters the wound metabolism and brings about a change of pH. In this work, porous silicon photonic films were coated with the pH-responsive polymer poly(2-diethylaminoethyl acrylate). We demonstrated that the pH-responsive polymer deposited on the surface of the photonic film acts as a barrier to prevent water from penetrating inside the porous matrix at neutral pH. Moreover, the device demonstrated optical pH sensing capability visible by the unaided eye.

Towards developing an efficient sensitive element for trinitrotoluene detection: TiO2 thin films functionalized with molecularly imprinted copolymer films

NASA Astrophysics Data System (ADS)

Lazau, Carmen; Iordache, Tanta-Verona; Florea, Ana-Mihaela; Orha, Corina; Bandas, Cornelia; Radu, Anita-Laura; Sarbu, Andrei; Rotariu, Traian

2016-10-01

In this study, TiO2 films were successfully grown in-situ onto a FTO substrate by a hydrothermal method, using TiCl4 as Ti precursor, and further on functionalized with a 2,4,6-trinitrotoluene-molecularly imprinted polymer (TNT-MIP) film as a preliminary step in developing a trinitrotoluene (TNT) reusable sensor to overcome the international security issues. For investigating the TiO2 film thickness, crystalline structure and morphology, the films were autoclaved at 200 °C at different times. The X-ray diffraction showed that TiO2 films possessed a rutile structure, with no cracks visible by atomic force microscopy (AFM), and the films morphology observed by scanning electron microscopy (SEM) was highly dependent upon the hydrothermal treatment time. Yet, the TiO2 films with a more porous surface were more suitable for TNT-MIP film deposit. Rheology of precursor polymer film solutions, based on poly (acrylonitrile-co-acrylic acid), poly (acrylonitrile-co-methacrylic acid) or poly (acrylonitrile- co-itaconic acid), and the structure and adherence of TNT-MIP films were investigated in order to establish the correct recipe of the MIP. The removal yield of TNT from the imprinted films, the thickness, the porosity and the compatibility with the inorganic TiO2 film were adequate for the poly (acrylonitrile-co-acrylic acid) system with an acrylonitrile: acrylic acid practical ratio of 86.1:13.9 (wt./wt.). Farmore, AFM morphology corroborated with SEM results highlighted the effect of TNT imprinting in the copolymer matrix as the surface of the imprinted layer was quite different from that of the non-imprinted layer.

Bottlebrush-Guided Polymer Crystallization Resulting in Supersoft and Reversibly Moldable Physical Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, William F. M.; Xie, Guojun; Vatankhah Varnoosfaderani, Mohammad

The goal of this study is to use ABA triblock copolymers with central bottlebrush B segments and crystalline linear chain A segments to demonstrate the effect of side chains on the formation and mechanical properties of physical networks cross-linked by crystallites. For this purpose, a series of bottlebrush copolymers was synthesized consisting of central amorphous bottlebrush polymer segments with a varying degree of polymerization (DP) of poly(n-butyl acrylate) (PnBA) side chains and linear tail blocks of crystallizable poly(octadecyl acrylate-stat-docosyl acrylate) (poly(ODA-stat-DA)). The materials were generated by sequential atom transfer radical polymerization (ATRP) steps starting with a series of bifunctional macroinitiatorsmore » followed by the growth of two ODA-stat-DA linear-chain tails and eventually growing poly(nBA) side chains with increasing DPs. Crystallization of the poly(ODA-stat-DA) tails resulted in a series of reversible physical networks with bottlebrush strands bridging crystalline cross-links. They displayed very low moduli of elasticity of the order of 10 3–10 4 Pa. These distinct properties are due to the bottlebrush architecture, wherein densely grafted side chains play a dual role by facilitating disentanglement of the network strands and confining crystallization of the linear-chain tails. This combination leads to physical cross-linking of supersoft networks without percolation of the crystalline phase. The cross-link density was effectively controlled by the DP of the side chains with respect to the DP of the linear tails (n A). Furthermore, shorter side chains allowed for crystallization of the linear tails of neighboring bottlebrushes, while steric repulsion between longer side chains hindered the phase separation and crystallization process and prevented network formation.« less

Bottlebrush-Guided Polymer Crystallization Resulting in Supersoft and Reversibly Moldable Physical Networks

DOE PAGES

Daniel, William F. M.; Xie, Guojun; Vatankhah Varnoosfaderani, Mohammad; ...

2017-02-24

The goal of this study is to use ABA triblock copolymers with central bottlebrush B segments and crystalline linear chain A segments to demonstrate the effect of side chains on the formation and mechanical properties of physical networks cross-linked by crystallites. For this purpose, a series of bottlebrush copolymers was synthesized consisting of central amorphous bottlebrush polymer segments with a varying degree of polymerization (DP) of poly(n-butyl acrylate) (PnBA) side chains and linear tail blocks of crystallizable poly(octadecyl acrylate-stat-docosyl acrylate) (poly(ODA-stat-DA)). The materials were generated by sequential atom transfer radical polymerization (ATRP) steps starting with a series of bifunctional macroinitiatorsmore » followed by the growth of two ODA-stat-DA linear-chain tails and eventually growing poly(nBA) side chains with increasing DPs. Crystallization of the poly(ODA-stat-DA) tails resulted in a series of reversible physical networks with bottlebrush strands bridging crystalline cross-links. They displayed very low moduli of elasticity of the order of 10 3–10 4 Pa. These distinct properties are due to the bottlebrush architecture, wherein densely grafted side chains play a dual role by facilitating disentanglement of the network strands and confining crystallization of the linear-chain tails. This combination leads to physical cross-linking of supersoft networks without percolation of the crystalline phase. The cross-link density was effectively controlled by the DP of the side chains with respect to the DP of the linear tails (n A). Furthermore, shorter side chains allowed for crystallization of the linear tails of neighboring bottlebrushes, while steric repulsion between longer side chains hindered the phase separation and crystallization process and prevented network formation.« less

Biofluidic Transport and Molecular Recognition in Polymer Microdevices

DTIC Science & Technology

2005-04-29

flexible membrane separating the particles and reservoir. B. Using photopolymerizable wires, an electrolysis pump was fabricated on a microdevice. It...Antigen detection was accomplished by grafting the approximate antibody or sensing compound via acrylation and polymerization to the surface. Figure 14...were detected with assay times of approximately 10 minutes. Figure 15 shows detection data for a compound (glucagon) that is impossible to detect by

Responsive copolymers for enhanced petroleum recovery. Quarterly technical progress report, December 21, 1994--March 22, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCormick, C.; Hester, R.

The purpose of this study is to extend the concept of micellar polymerization to more complex systems, and to explore the responsive nature of hydrophobically modified polyelectrolytes by tailoring the microstructure. The synthesis of hydrophobically modified acrylamide/acrylic acid copolymer is described. These types of polymers are of interest as thickening agents utilized in enhanced oil recovery.

Induced polymersome formation from a diblock PS-b-PAA polymer via encapsulation of positively charged proteins and peptides.

PubMed

Hvasanov, David; Wiedenmann, Jörg; Braet, Filip; Thordarson, Pall

2011-06-14

In contrast to simple salts or negatively charged macromolecules, positively charged proteins and peptides including cytochrome c (yeast) and poly-L-lysine are efficiently encapsulated while inducing the formation of polymersomes from polystyrene(140)-b-poly(acrylic acid)(48) (PS(140)-b-PAA(48)). This journal is © The Royal Society of Chemistry 2011

Quercetin conjugated poly(β-amino esters) nanogels for the treatment of cellular oxidative stress.

PubMed

Gupta, Prachi; Authimoolam, Sundar P; Hilt, J Zach; Dziubla, Thomas D

2015-11-01

PβAE polymers have emerged as highly promising candidates for biomedical and drug delivery applications owing to their tunable, degradable and pH sensitive properties. These polymeric systems can serve as prodrug carriers for the delivery of bioactive compounds which suffer from poor aqueous solubility, low bioavailability and are biologically unstable, such as the antioxidant, quercetin. Using acrylate functionalized quercetin, it is possible to incorporate the polyphenol into the backbone of the polymer matrix, permitting slow release of the intact molecule which is perfectly timed with the polymer degradation. While formulating these quercetin conjugated PβAE matrix into nanocarriers would allow for multiple delivery routes (oral, intravenous, inhalation etc.), well known oil-water nano-emulsion formulation methods are not amenable to the crosslinked hydrolytically sensitive nanoparticle/nanogel. In this work, a single-phase reaction-precipitation method was developed to formulate quercetin conjugated PβAE nanogels (QNG) via reaction of acrylated quercetin (4-5 acrylate groups) with a secondary diamine under dilute conditions using acetonitrile as the reaction medium, resulting in a self-stabilized suspension. The proposed approach permits the post synthesis modification of the spherical nanogels with a PEGylated coating, enhancing their aqueous stability and stealth characteristics. Nanogel size was controlled by varying feed reactant concentrations, achieving drug loadings of 25-38wt%. Uniform release of quercetin over 45-48h was observed upon PβAE ester hydrolysis under physiological conditions with its retained antioxidant activity over the extended times. Here we present the first demonstration of using poly(beta amino ester) chemistry to form nanogels composed of a bioactive polyphenol for the control of cellular oxidative stress. Previous nanogel and nanoparticle approaches, which use a water phase, are not readily amenable to PBAE chemistry due to their hydrolytic sensitivity. Here we demonstrate a simple approach to control particle size, modify surface chemistry and achieve highly regulated controlled release of active antioxidants, which can protect cells against external oxidative stress signals. This work has importance in the area of controlling material biocompatibility through augmenting the antioxidant status of cells. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The adsorption of cationic and amphoteric copolymers on glass surfaces: zeta potential measurements, adsorption isotherm determination, and FT Raman characterization.

PubMed

Tartakovsky, Alla; Drutis, Dane M; Carnali, Joseph O

2003-07-15

The adsorption of cationic and amphoteric copolymers onto controlled pore glass (CPG) powders has been studied by measurement of the powder particle zeta (zeta) potential, by determination of the adsorption isotherm, and by FT Raman measurements of the polymer-coated powder. The cationic polymers consisted chiefly of homopolymers of dimethyldiallylammonium chloride (DMDAAC) or copolymers of DMDAAC and acrylamide. The amphoteric polymers studied included copolymers of DMDAAC and acrylic acid. The comonomer ratio was varied to explore the dependence of cationic charge density on the extent and effect of adsorption. Both types of polymers adsorb onto the anionic glass surface via an ion-exchange mechanism. Consequently, a correspondingly higher mass of a low-charge-density copolymer adsorbs than of a cationic homopolymer. The presence of the anionic portion in the amphoteric polymers does not significantly alter this picture. The zeta potential, however, reflects the overall nature of the polymer. Cationic polymers effectively neutralize the glass surface, while amphoteric polymers leave the zeta potential net negative. Adsorption isotherms, determined via the depletion technique using colloidal titration, were used to "calibrate" a FT Raman method. The latter was used to determined the amount of adsorbed polymer under solution conditions in which colloidal titration could not be performed.

Synthesis and characterization of polymer matrix composite material with combination of ZnO filler and nata de coco fiber as a candidate of semiconductor material

NASA Astrophysics Data System (ADS)

Saputra, Asep Handaya; Anindita, Hana Nabila

2015-12-01

Synthesis of semiconductor composite using acrylic matrix filled with ZnO and nata de coco fiber has been conducted in this research. The purpose of this research is to obtain semiconductor composite material that has a good mechanical strength and thermal resistance. In situ polymerization method is used in this research and the composites are ready to be characterized after 12 hours. The main parameter that is characterized is the electric conductivity of the composite. Additional parameters are also characterized such as composite's elastic modulus and glass transition temperature. The composites that has been made in this research can be classified as semiconductor material because the conductivity is in the range of 10-8-103 S/cm. In general the addition of ZnO and nata de coco filler can increase the conductivity of the composite. The highest semiconductor characteristic in acrylic/ZnO composite is obtained from 30% volume filler that reach 3.4 x 10-7 S/cm. Similar with acrylic/ZnO composite, in acrylic/nata de coco fiber composite the highest semiconductor characteristic is also obtained from 30% volume filler that reach 1.15 x 10-7 S/cm. Combination of 20% volume of ZnO, 10% volume of nata de coco, and 70% volume of acrylic resulting in composite with electric conductivity of 1.92 x 10-7 S/cm. In addition, combination of ZnO and nata de coco fiber as filler in composite can also improve the characteristic of composite where composite with 20% volume of ZnO filler and 10% volume of nata de coco fiber resulting in composite with elastic modulus of 1.79 GPa and glass transition temperature of 175.73°C which is higher than those in acrylic/ZnO composite.

In vitro and in vivo biocompatibility study on laser 3D microstructurable polymers

NASA Astrophysics Data System (ADS)

Malinauskas, Mangirdas; Baltriukiene, Daiva; Kraniauskas, Antanas; Danilevicius, Paulius; Jarasiene, Rasa; Sirmenis, Raimondas; Zukauskas, Albertas; Balciunas, Evaldas; Purlys, Vytautas; Gadonas, Roaldas; Bukelskiene, Virginija; Sirvydis, Vytautas; Piskarskas, Algis

2012-09-01

Films and microstructured scaffolds have been fabricated using direct laser writing out of different polymers: hybrid organic-inorganic ORMOCORE b59, acrylate-based AKRE23, novel organic-inorganic Zr containing hybrid SZ2080, and biodegradable PEG-DA-258. Adult myogenic stem cells were grown on these surfaces in vitro. Their adhesion, growth, and viability test results suggest good potential applicability of the materials in biomedical practice. Pieces of these polymers were implanted in rat's paravertebral back tissue. Histological examination of the implants and surrounding tissue ex vivo after 3 weeks of implantation was conducted and results show the materials to be at least as biocompatible as surgical clips or sutures. The applied direct laser writing technique seems to offer good future prospects in a polymeric 3D scaffold design for artificial tissue engineering with autologous stem cells.

Novel high-performance scattering materials for use in energy-saving light fittings and skylights based on polymer pigmented with polymer

NASA Astrophysics Data System (ADS)

Smith, Geoffrey B.; Earp, Alan; Franklin, Jim B.; McCredie, Geoffrey

2001-11-01

Simple quantitative performance criteria are developed for translucent materials in terms of hemispherical visible transmittance, and angular spread of transmitted luminance using a half angle. Criteria are linked to applications in luminaires and skylights with emphasis on maximising visible throughput while minimising glare. These basic criteria are also extended to angle of incidence changes which are substantial. Example data is provided showing that acrylic pigmented with spherical polymer particles can have total hemispherical transmittance with weak thickness dependence, which is better than clear sheet, while the spread of transmitted light is quite thickness-sensitive and occurs over wider angles than inorganic pigments. This combination means significantly fewer lamps can achieve specified lux levels with low glare, and smaller skylights can provide higher, more uniform daylight illuminance.

Kinetics and Mechanism of in situ Simultaneous Formation of Metal Nanoparticles in Stabilizing Polymer Matrix

NASA Astrophysics Data System (ADS)

Pomogailo, Anatolii D.; Dzhardimalieva, Gulzhian I.; Rozenberg, Aleksander S.; Muraviev, Dmitri N.

2003-12-01

The kinetic peculiarities of the thermal transformations of unsaturated metal carboxylates (transition metal acrylates and maleates as well as their cocrystallites) and properties of metal-polymer nanocomposites formed have been studied. The composition and structure of metal-containing precursors and the products of the thermolysis were identified by X-ray analysis, optical and electron microscopy, magnetic measurements, EXAFS, IR and mass spectroscopy. The thermal transformations of metal-containing monomers studied are the complex process including dehydration, solid phase polymerization, and thermolysis process which proceed at varied temperature ranges. At 200-300°C the rate of thermal decay can be described by first-order equations. The products of decompositions are nanometer-sized particles of metal or its oxides with a narrow size distribution (the mean particle diameter of 5-10nm) stabilized by the polymer matrix.

Use of proteins to minimize the physical aging of EUDRAGIT sustained release films.

PubMed

Kucera, Shawn A; McGinity, James W; Zheng, Weijia; Shah, Navnit H; Malick, A Waseem; Infeld, Martin H

2007-07-01

The objective of this study was to investigate the influence of two proteins, albumin and type B gelatin, on the physical aging of EUDRAGIT RS 30 D and RL 30 D coated theophylline pellets. The physicomechanical properties of sprayed films, thermal properties of cast films, influence of proteins on the zeta potential and particle size of the dispersion, and the release of proteins from cast films under simulated dissolution conditions were investigated. The release rate of theophylline decreased significantly over time from pellets coated with an acrylic dispersion containing 10% albumin when there was no acidification of the acrylic dispersion; however, when pellets were coated with an acidified EUDRAGIT/albumin dispersion, the theophylline release rate was stable for dosage forms stored in the absence of humidity. The drug release rate was faster for pellets coated with acrylic dispersions containing 10% gelatin compared to the albumin-containing formulations. When sprayed films were stored at 40 degrees C/75% RH, the water vapor permeability decreased significantly for both EUDRAGIT films and those containing EUDRAGIT and albumin; however, there was no significant change in this parameter when 10% gelatin was present. Albumin was released from the acrylic films when the pH of the dissolution media was below the isoelectric point of the protein while no quantitative release of gelatin was observed in pH 1.2 or 7.4 media. The effect of gelatin to prevent the decrease in drug release rate was due to stabilization in water vapor permeability of the film. Acidification of the polymeric dispersion resulted in electrostatic repulsive forces between albumin and the acrylic polymer, which stabilized the drug release rate when the dosage forms were stored in aluminum induction sealed containers at both 40 degrees C/75% RH and 25 degrees C/60% RH.

Hierarchically porous materials from layer-by-layer photopolymerization of high internal phase emulsions.

PubMed

Sušec, Maja; Ligon, Samuel Clark; Stampfl, Jürgen; Liska, Robert; Krajnc, Peter

2013-06-13

A combination of high internal phase emulsion (HIPE) templating and additive manufacturing technology (AMT) is applied for creating hierarchical porosity within an acrylate and acrylate/thiol-based polymer network. The photopolymerizable formulation is optimized to produce emulsions with a volume fraction of droplet phase greater than 80 vol%. Kinetic stability of the emulsions is sufficient enough to withstand in-mold curing or computer-controlled layer-by-layer stereolithography without phase separation. By including macroscale cellular cavities within the build file, a level of controlled porosity is created simultaneous to the formation of the porous microstructure of the polyHIPE. The hybrid HIPE-AMT technique thus provides hierarchically porous materials with mechanical properties tailored by the addition of thiol chain transfer agent. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flavin-N5 Covalent Intermediate in a Nonredox Dehalogenation Reaction Catalyzed by an Atypical Flavoenzyme.

PubMed

Dai, Yumin; Kizjakina, Karina; Campbell, Ashley C; Korasick, David A; Tanner, John J; Sobrado, Pablo

2018-01-04

The flavin-dependent enzyme 2-haloacrylate hydratase (2-HAH) catalyzes the conversion of 2-chloroacrylate, a major component in the manufacture of acrylic polymers, to pyruvate. The enzyme was expressed in Escherichia coli, purified, and characterized. 2-HAH was shown to be monomeric in solution and contained a non-covalent, yet tightly bound, flavin adenine dinucleotide (FAD). Although the catalyzed reaction was redox-neutral, 2-HAH was active only in the reduced state. A covalent flavin-substrate intermediate, consistent with the flavin-acrylate iminium ion, was trapped with cyanoborohydride and characterized by mass spectrometry. Small-angle X-ray scattering was consistent with 2-HAH belonging to the succinate dehydrogenase/fumarate reductase family of flavoproteins. These studies establish 2-HAH as a novel noncanonical flavoenzyme. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of Paraffin@Poly(styrene-co-acrylic acid) Phase Change Nanocapsules via Combined Miniemulsion/Emulsion Polymerization.

PubMed

Zhang, Feng; Liu, Tian-Yu; Hou, Gui-Hua; Guan, Rong-Feng; Zhang, Jun-Hao

2018-06-01

The fast development of solid-liquid phase change materials calls for nanomaterials with large specific surface area for rapid heat transfer and encapsulation of phase change materials to prevent potential leakage. Here we report a combined miniemulsion/emulsion polymerization method to prepare poly(styrene-co-acrylic acid)-encapsulated paraffin (paraffin@P(St-co-AA)) nanocapsules. The method could suppress the shortcomings of common miniemulsion polymerization (such as evaporation of monomer and decomposition of initiator during ultrasonication). The paraffin@P(St-co-AA) nanocapsules are uniform in size and the polymer shell can be controlled by the weight ratio of St to paraffin. The phase change behavior of the nanocapsules is similar to that of pure paraffin. We believe our method can also be utilized to synthesize other core-shell phase change materials.

Synthesis and characterization of functional acrylic copolymers via RAFT mini-emulsion polymerization

NASA Astrophysics Data System (ADS)

Yılmaz, Onur; Özkan, ćiǧdem Kılıçarislan; Yılmaz, Catalina N.; Yorgancıoǧlu, Ali; Özgünay, Hasan; Karavana, Hüseyin Ata

2017-12-01

Copolymers bearing reactive functional groups with controlled molecular weights are of importance since they can be used in many fields such as composites, coatings, membranes, catalysis, biology, optoelectronics, pharmaceuticals, etc. In the present study low molecular weight copolymers based on butyl acrylate (BA) and methyl methacrylate (MMA) in combination with reactive functional monomers of vinyl trietoxysilane (VTES), 3-trimetoxysilylpropyl methacrylate (TMSPMA) and glycidyl methacrylate (GMA) were synthesized via RAFT mini-emulsion technique using 2-cyano 2-propyldodecyldithiocarbonate as CTA agent. The results showed that the average molecular weights of copolymers were close to the theoretical values. On the other hand, PDI values were found to be higher than conventional RAFT polymers. The particle sizes of the latexes were small with very homogenous distributions and good stability. FTIR, H-NMR and TGA results verified the success of copolymer syntheses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balhoff, Matthew; Tavassoli, Shayan; Fei Ho, Jostine

The potential leakage of hydrocarbon fluids or CO 2 out of subsurface formations through wells with fractured cement or debonded microannuli is a primary concern in oil and gas production and CO 2 storage. The presence of fractures in a cement annulus with apertures on the order of 10–300 microns can pose a significant leakage danger with effective permeability in the range of 0.1–1 mD (millidarcy). Leakage pathways with small apertures are often difficult to repair using conventional oilfield cement, thus a low-viscosity sealant that can be easily placed into these fractures while providing an effective seal is desired. Themore » development of a novel application using pH-triggered polymeric sealants could potentially be the solution to plugging these fractures and that was the research aim of this study. The application is based on the transport and reaction of a low-pH poly(acrylic acid) polymer through fractures in strongly alkaline cement. The pH-sensitive microgels viscosify upon neutralization with cement to become highly swollen gels with substantial yield stress that can block fluid flow. Experiments in a cement fracture determined the effects of the viscosification and gel deposition via real-time visual observation and measurements of pressure gradient and effluent pH. While the pH-triggered gelling mechanism and rheology measurements of the neutralized polymer gel show promising results, the polymer solution in contact with cement undergoes an undesirable reaction known as polymer syneresis. Syneresis is caused by the release of calcium cation from cement that collapses the polymer network. Syneresis produces an unstable calcium-precipitation byproduct that is detrimental to the strength and stability of the gel in place. As a result, gel-sealed leakage pathways that subjected to various degrees of syneresis often failed to hold back pressures. Several chemicals were studied to inhibit polymer syneresis and tested for pretreatment of cement cores to remove calcium and prevent syneresis during polymer placement. A chelating agent, sodium triphosphate (Na 5P 3O 10), was found to successfully eliminate syneresis without compromising the injectivity of polymer solution during placement. Polymer gel strength is determined by recording the maximum holdback pressure gradients during liquid breakthrough tests after various periods of pretreatment and polymer shut-in time. Cores pretreated with Na 5P 3O 10 successfully held up to an average of 80 psi/ft, which is significantly greater than the expected threshold value of about 0.1-5 psi/ft required to prevent flow in a typical CO 2 leakage scenario. The use of such inexpensive, pH-triggered poly-acrylic acid polymer allows long-term robust seal of leaky wellbores under high pH conditions.« less

Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS)

NASA Technical Reports Server (NTRS)

Pojman, John A.; Bessonov, Nicholas; Volpert, Vitaly; Wilke, Hermann

2003-01-01

Almost one hundred years ago Korteweg published a theory of how stresses could be induced in miscible fluids by concentration gradients, causing phenomena that would appear to be the same as with immiscible fluids. Miscible fluids could manifest a transient or effective interfacial tension (EIT). To this day, there has been no definitive experiment to confirm Korteweg's model but numerous fascinating and suggestive experiments have been reported. The goal of TIPMPS is to answer the question: Can concentration and temperature gradients in miscible materials induce stresses that cause convection? Many polymer processes involving miscible monomer and polymer systems could be affected by fluid flow and so this work could help understand miscible polymer processing, not only in microgravity, but also on earth. Demonstrating the existence of this phenomenon in miscible fluids will open up a new area of study for materials science. The science objectives of TIPMPS are: (1) Determine if convection can be induced by variation of the width of a miscible interface; (2) Determine if convection can be induced by variation of temperature along a miscible interface; (3) Determine if convection can be induced by variation of conversion along a miscible interface An interface between two miscible fluids can best be created via a spatially-selective photopolymerization of dodecyl acrylate with a photoinitiator, which allows the creation of precise and accurate concentration gradients between polymer and monomer. Optical techniques will be used to measure the refractive index variation caused by the resultant temperature and concentration fields. The viscosity of the polymer will be measured from the increase in the fluorescence of pyrene. Because the large concentration and temperature gradients cause buoyancy-driven convection that prevents the observation of the predicted flows, the experiment must be done in microgravity. In this report, we will consider our efforts to estimate the square gradient parameter, k, and our use of the estimates in modeling of the planned TIPMPS experiments. We developed a model consisting of the heat and diffusion equations with convective terms and of the Navier-Stokes equations with an additional volume force written in the form of the Korteweg stresses arising from nonlocal interaction in the fluid. The fluid's viscosity dependence on polymer conversion and temperature was taken from measurements of poly(dodecyl acrylate). Numerical modeling demonstrated that significant flows would arise for conditions corresponding to the planned experiments.

New Hydrophobic IOL Materials and Understanding the Science of Glistenings.

PubMed

Tetz, Manfred; Jorgensen, Matthew R

2015-01-01

An introduction to the history of intraocular lenses (IOLs) is given, leading up to modern hydrophobic examples. The roles of hydrophobicity, hygroscopy, materials chemistry, and edge design are discussed in the context of IOLs. The four major types of IOL materials are compared in terms of their chemistry and biocompatibility. An example of a modern "hydrophobic" acrylic polymer with higher water content is discussed in detail.

Novel Ultraviolet Light Absorbing Polymers For Optical Applications

NASA Astrophysics Data System (ADS)

Doddi, Namassivaya; Yamada, Akira; Dunks, Gary B.

1988-07-01

Ultraviolet light absorbing monomers have been developed that can be copolymerized with acrylates. The composition of the resultant stable copolymers can be adjusted to totally block the transmission of light below about 430 nm. Fabrication of lenses from the materials is accomplished by lathe cutting and injection molding procedures. These ultraviolet light absorbing materials are non-mutagenic and non-toxic and are currently being used in intraocular lenses.

Development and characterization of adjustable refractive index scattering epoxy acrylate polymer layers

NASA Astrophysics Data System (ADS)

Eiselt, Thomas; Preinfalk, Jan; Gleißner, Uwe; Lemmer, Uli; Hanemann, Thomas

2016-09-01

This work presents different polymer diffusing films for optical components. In optical applications it is sometimes important to have a film with an adjusted refractive index, scattering properties and a low surface roughness. These diffusing films can be used to increase the efficiency of optical components like organic light emitting diodes (OLEDs). In this study three different epoxy acrylate mixtures containing Syntholux 291 EA, bisphenol a glycerolate dimethacrylate, Sartomer SR 348 L are characterized and optimized with different additives. The adjustable refractive index of the material is achieved with a chemical doping by 9-vinylcarbazole. Titanium nanoparticles in the mixtures generate light scattering and increase the refractive index additionally. To prevent sedimentation and agglomeration of these nanoparticles, a stabilization agent [2-(2-methoxyethoxy)ethoxy]acetic acid is added to the mixture. Other ingredients are a UV-starter and thermal starter for the radical polymerization. A high power stirrer (ultraturrax) is used to mix and disperse all chemical substances together to a homogenous mixture. The viscosity behavior of the mixtures is an important property for the selection of the production method and gets characterized. After the mixing, the monomer mixture is applied on glass substrates by blade coating or screen printing. To initiate the chain growing (polymerization) the produced films are irradiated for 10 minutes long with UV light (UV LED Spot Hönle, 405 nm). After this step a final post bake from the layers in the oven (150°C, 30 min.) is operated. Light transmission measurements (UV-Vis) of the polymer matrix and roughness measurements complement the characterization.

High-refractive index polyacrylates based on quinolinone-structures for intraocular lenses

NASA Astrophysics Data System (ADS)

Dams, Christian; Helmstetter, Simon; Hampp, Norbert

2017-02-01

Intraocular lenses (IOL) have experienced an expanding application over the last decades. Not only they can be used to cure cataract caused blindness, but they are also appointed to ease visual impairments (e.g. -18 - 10 dioptre or astigmatism).[1] These phake IOL require materials with very high refractive indices due to the limited space at the implanting position in the eye of the patient. This enables less invasive operations and such with smaller incisions.[2] Quinolinone derivates, like carbostyril, are currently known from drug design and as a main structural component of several antibiotics.[3] Although they show high refractive indices and good dispersions they have not yet been used in materials for ophthalmic applications. We synthesized and characterized novel high refractive index polymers containing quinolinones as the main refractive unit of the structure.[4] We showed that it was possible to build quinolinone polymers with high refractive indices up to 1.685 at 589 nm. Using this material it would theoretically be possible to reduce the lens thickness of an IOL to under 40 percent compared to a commercial hydrogel lens with a refractive index of 1.470. We also used the synthesized quinolinone acrylates to create hydrophobic copolymers with improved physical properties and high transmission in the visible spectral range. Besides the good lightfastness these copolymers also showed very low tendencies of glistening. In conclusion quinolinones show attractive performances for the usage as a component in acrylic copolymers. If the requirements for IOL keep rising in the coming years these monomers could be used to boost the refractive index of ophthalmic polymer compositions.

Fluorescent Polystyrene Microbeads as Invisible Security Ink and Optical Vapor Sensor for 4-Nitrotoluene.

PubMed

Sonawane, Swapnil L; Asha, S K

2016-04-27

Color-tunable solid-state emitting polystyrene (PS) microbeads were developed by dispersion polymerization, which showed excellent fluorescent security ink characteristics along with sensitive detection of vapors of nitro aromatics like 4-nitro toluene (4-NT). The fluorophores pyrene and perylenebisimide were incorporated into the PS backbone as acrylate monomer and acrylate cross-linker, respectively. Solid state quantum yields of 94 and 20% were observed for the pyrene and perylenebisimide, respectively, in the PS/Py and PS/PBI polymers. The morphology and solid state fluorescence was measured by SEM, fluorescence microscopy, and absorbance and fluorescence spectroscopy techniques. The ethanol dispersion of the polymer could be used directly as a fluorescent security "invisible" ink, which became visible only under ultraviolet light. The color of the ink could be tuned depending on the amounts of the pyrene and perylenebisimide incorporated with blue and orange-green for pyrene alone or perylenebisimide alone beads respectively and various shades in between including pure white for beads incorporating both the fluorophores. More than 80% quenching of pyrene emission was observed upon exposure of the polymer in the form of powder or as spin-coated films to the vapors of 4-NT while the emission of perylenebisimide was unaffected. The limit of detection was estimated at 10(-5) moles (2.7 ppm) of 4-NT vapors. The ease of synthesis of the material along with its invisible ink characteristics and nitro aromatic vapor detection opens up new opportunities for exploring the application of these PS-based materials as optical sensors and fluorescent ink for security purposes.

Conducting electrospun fibres with polyanionic grafts as highly selective, label-free, electrochemical biosensor with a low detection limit for non-Hodgkin lymphoma gene.

PubMed

Kerr-Phillips, Thomas E; Aydemir, Nihan; Chan, Eddie Wai Chi; Barker, David; Malmström, Jenny; Plesse, Cedric; Travas-Sejdic, Jadranka

2018-02-15

A highly selective, label-free sensor for the non-Hodgkin lymphoma gene, with an aM detection limit, utilizing electrochemical impedance spectroscopy (EIS) is presented. The sensor consists of a conducting electrospun fibre mat, surface-grafted with poly(acrylic acid) (PAA) brushes and a conducting polymer sensing element with covalently attached oligonucleotide probes. The sensor was fabricated from electrospun NBR rubber, embedded with poly(3,4-ethylenedioxythiophene) (PEDOT), followed by grafting poly(acrylic acid) brushes and then electrochemically polymerizing a conducting polymer monomer with ssDNA probe sequence pre-attached. The resulting non-Hodgkin lymphoma gene sensor showed a detection limit of 1aM (1 × 10 -18 mol/L), more than 400 folds lower compared to a thin-film analogue. The sensor presented extraordinary selectivity, with only 1%, 2.7% and 4.6% of the signal recorded for the fully non-complimentary, T-A and G-C base mismatch oligonucleotide sequences, respectively. We suggest that such greatly enhanced selectivity is due to the presence of negatively charged carboxylic acid moieties from PAA grafts that electrostatically repel the non-complementary and mismatch DNA sequences, overcoming the non-specific binding. Copyright © 2017 Elsevier B.V. All rights reserved.

Acoustic Performance of Resilient Materials Using Acrylic Polymer Emulsion Resin.

PubMed

Kim, Haseog; Park, Sangki; Lee, Seahyun

2016-07-19

There have been frequent cases of civil complaints and disputes in relation to floor impact noises over the years. To solve these issues, a substantial amount of sound resilient material is installed between the concrete slab and the foamed concrete during construction. A new place-type resilient material is made from cement, silica powder, sodium sulfate, expanded-polystyrene, anhydrite, fly ash, and acrylic polymer emulsion resin. Its physical characteristics such as density, compressive strength, dynamic stiffness, and remanent strain are analyzed to assess the acoustic performance of the material. The experimental results showed the density and the dynamic stiffness of the proposed resilient material is increased with proportional to the use of cement and silica powder due to the high contents of the raw materials. The remanent strain, related to the serviceability of a structure, is found to be inversely proportional to the density and strength. The amount of reduction in the heavyweight impact noise is significant in a material with high density, high strength, and low remanent strain. Finally, specimen no. R4, having the reduction level of 3 dB for impact ball and 1 dB for bang machine in the single number quantity level, respectively, is the best product to obtain overall acoustic performance.

Oriented antibody immobilization to polystyrene macrocarriers for immunoassay modified with hydrazide derivatives of poly(meth)acrylic acid

PubMed Central

Shmanai, Vadim V; Nikolayeva, Tamara A; Vinokurova, Ludmila G; Litoshka, Anatoli A

2001-01-01

Background Hydrophobic polystyrene is the most common material for solid phase immunoassay. Proteins are immobilized on polystyrene by passive adsorption, which often causes considerable denaturation. Biological macromolecules were found to better retain their functional activity when immobilized on hydrophilic materials. Polyacrylamide is a common material for solid-phase carriers of biological macromolecules, including immunoreagents used in affinity chromatography. New macroformats for immunoassay modified with activated polyacrylamide derivatives seem to be promising. Results New polymeric matrices for immunoassay in the form of 0.63-cm balls which contain hydrazide functional groups on hydrophilic polymer spacer arms at their surface shell are synthesized by modification of aldehyde-containing polystyrene balls with hydrazide derivatives of poly(meth)acrylic acid. The beads contain up to 0.31 μmol/cm2 active hydrazide groups accessible for covalent reaction with periodate-oxidized antibodies. The matrices obtained allow carrying out the oriented antibody immobilization, which increases the functional activity of immunosorbents. Conclusions An efficient site-directed antibody immobilization on a macrosupport is realized. The polymer hydrophilic spacer arms are the most convenient and effective tools for oriented antibody coupling with molded materials. The suggested scheme can be used for the modification of any other solid supports containing electrophilic groups reacting with hydrazides. PMID:11545680

Bilayered Films Based on Novel Polymer Derivative for Improved Ocular Therapy of Gatifloxacin

PubMed Central

Aher, Naval Dinesh; Nair, Hema Ajit

2014-01-01

Context. Thiomers could prove to be suitable mucoadhesives for fabrication of ocular inserts. Objective. The study intends to explore the application of thiolated sodium alginate (TSA) to the preparation of bilayered ocular inserts of gatifloxacin. Methods. Cysteine moieties were grafted onto sodium alginate (SA) and the resultant thiomer was characterized for relevant physicochemical properties. Bilayered inserts were fabricated with a mucoadhesive immediate release layer composed of either SA or TSA and a sustained release layer composed of acrylates. Films were prepared by solvent evaporation and evaluated for mechanical properties, drug content, and in vitro release. Results and Discussion. The synthesized TSA possessed 248.80 ± 49.7 μmol thiol groups/gm and its solutions thickened on standing due to disulphide bridging. Its films showed improved mucoadhesion and also a strikingly beneficial property of resisting erosion and remaining as a hydrated adhesive layer for the duration of drug release. The bilayered films were found to be flexible, with good folding endurance, uniform thickness, and appropriate drug content, and showed a release of about 80% of loaded gatifloxacin in 12 h. Conclusion. The study demonstrates promise in employing thiolated polymer in conjunction with acrylates for the design of ocular inserts for twice a day therapy with gatifloxacin. PMID:24516362

Optically transparent super-hydrophobic thin film fabricated by reusable polyurethane-acrylate (PUA) mold

NASA Astrophysics Data System (ADS)

Park, J.-S.; Park, J.-H.; Lee, D.-W.

2018-02-01

In this paper, we describe a simple manufacturing method for producing an optically transparent super-hydrophobic polymer thin film using a reusable photo-curable polymer mold. Soluble photoresist (PR) molds were prepared with under-exposed and under-baked processes, which created unique hierarchical micro/nano structures. The reverse phase of the PR mold was replicated on the surface of polydimethylsiloxane (PDMS) substrates. The unique patterns on the replicated PDMS molds were successfully transferred back to the UV curable polyurethane-acrylate (PUA) using a laboratory-made UV exposure system. Continuous production of the super-hydrophobic PDMS thin film was demonstrated using the reusable PUA mold. In addition, hydrophobic nano-silica powder was sprayed onto the micro/nano structured PDMS surfaces to further improve hydrophobicity. The fabricated PDMS thin films with hierarchical surface texturing showed a water contact angle  ⩾150°. Excellent optical transmittance within the range of visible light of wavelengths between 400-800 nm was experimentally confirmed using a spectrophotometer. High efficiency of the super-hydrophobic PDMS film in optical transparency was also confirmed using solar panels. The fabricated PUA molds are very suitable for use in roll-to-roll or roll-to-plate systems which allow continuous production of super-hydrophobic thin films with an excellent optical transparency.

Shape Memory Polymers Containing Higher Acrylate Content Display Increased Endothelial Cell Attachment

PubMed Central

Govindarajan, Tina; Shandas, Robin

2018-01-01

Shape Memory Polymers (SMPs) are smart materials that can recall their shape upon the application of a stimulus, which makes them appealing materials for a variety of applications, especially in biomedical devices. Most prior SMP research has focused on tuning bulk properties; studying surface effects of SMPs may extend the use of these materials to blood-contacting applications, such as cardiovascular stents, where surfaces that support rapid endothelialization have been correlated to stent success. Here, we evaluate endothelial attachment onto the surfaces of a family of SMPs previously developed in our group that have shown promise for biomedical devices. Nine SMP formulations containing varying amounts of tert-Butyl acrylate (tBA) and Poly(ethylene glycol) dimethacrylate (PEGDMA) were analyzed for endothelial cell attachment. Dynamic mechanical analysis (DMA), contact angle studies, and atomic force microscopy (AFM) were used to verify bulk and surface properties of the SMPs. Human umbilical vein endothelial cell (HUVEC) attachment and viability was verified using fluorescent methods. Endothelial cells preferentially attached to SMPs with higher tBA content, which have rougher, more hydrophobic surfaces. HUVECs also displayed an increased metabolic activity on these high tBA SMPs over the course of the study. This class of SMPs may be promising candidates for next generation blood-contacting devices. PMID:29707382

Acoustic Performance of Resilient Materials Using Acrylic Polymer Emulsion Resin

PubMed Central

Kim, Haseog; Park, Sangki; Lee, Seahyun

2016-01-01

There have been frequent cases of civil complaints and disputes in relation to floor impact noises over the years. To solve these issues, a substantial amount of sound resilient material is installed between the concrete slab and the foamed concrete during construction. A new place-type resilient material is made from cement, silica powder, sodium sulfate, expanded-polystyrene, anhydrite, fly ash, and acrylic polymer emulsion resin. Its physical characteristics such as density, compressive strength, dynamic stiffness, and remanent strain are analyzed to assess the acoustic performance of the material. The experimental results showed the density and the dynamic stiffness of the proposed resilient material is increased with proportional to the use of cement and silica powder due to the high contents of the raw materials. The remanent strain, related to the serviceability of a structure, is found to be inversely proportional to the density and strength. The amount of reduction in the heavyweight impact noise is significant in a material with high density, high strength, and low remanent strain. Finally, specimen no. R4, having the reduction level of 3 dB for impact ball and 1 dB for bang machine in the single number quantity level, respectively, is the best product to obtain overall acoustic performance. PMID:28773711

Properties, ageing behavior and stability of bipolar films containing nano-layers of allylamine and acrylic acid plasma polymers

NASA Astrophysics Data System (ADS)

Aziz, Gaelle; Asadian, Mahtab; Declercq, Heidi; Morent, Rino; De Geyter, Nathalie

2018-06-01

In this work, a dielectric barrier discharge (DBD) has been used for the deposition of bipolar films containing alternating nano-layers of plasma polymerized allylamine (PPAam) and acrylic acid (PPAac). Various films were obtained by varying the single-layer thickness of each plasma polymer while maintaining a constant total film thickness and two kinds of films were fabricated via different depositing sequences (PPAam/Aac and PPAac/Aam). Films properties, ageing in air and stability in water over a 7 days period were investigated. Results showed that, COO- and NH3+ polar entities, generated from the interaction of PPAam and PPAac, are present in the bipolar films. Concerning the films stability, the different reaction mechanisms involved in the formation of each kind of films resulted in a higher amount of polar groups in the PPAam/Aac films; this conferred these films a higher stability than PPAac/Aam. Concerning the films ageing behavior, all prepared samples underwent some kind of ageing which was found to be dependent on the deposition sequence. Results also showed that bipolar coatings exhibited better cell-material interactions compared to PPAam and PPAac films; with a better cell viability observed on PPAam/Aac coatings after 1 and 7 days culture.

Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barleany, Dhena Ria, E-mail: dbarleany@yahoo.com; Ulfiyani, Fida; Istiqomah, Shafina

Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w{sup −1} acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 gmore » g{sup −1} of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g{sup −1} and 523 g g{sup −1} for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM)« less

Surface grafted antibodies: controlled architecture permits enhanced antigen detection.

PubMed

Sebra, Robert P; Masters, Kristyn S; Bowman, Christopher N; Anseth, Kristi S

2005-11-22

The attachment of antibodies to substrate surfaces is useful for achieving specific detection of antigens and toxins associated with clinical and field diagnostics. Here, acrylated whole antibodies were produced through conjugation chemistry, with the goal of covalently photografting these proteins from surfaces in a controlled fashion, to facilitate rapid and sensitive antigenic detection. A living radical photopolymerization chemistry was used to graft the acrylated whole antibodies on polymer surfaces at controlled densities and spatial locations by controlling the exposure time and area, respectively. Copolymer grafts containing these antibodies were synthesized to demonstrate two principles. First, PEG functionalities were introduced to prevent nonspecific protein interactions and improve the reaction kinetics by increasing solvation and mobility of the antibody-containing chains. Both of these properties lead to sensitive (pM) and rapid (<20 min) detection of antigens with this surface modification technique. Second, graft composition was tailored to include multiple antibodies on the same grafted chains, establishing a means for simultaneously detecting multiple antigens on one grafted surface area. Finally, the addition of PEG spacers between the acrylate functionality and the pendant detection antibodies was tuned to enhance the detection of a short-half-life molecule, glucagon, in a complex biological environment, plasma.

Development of an in-process UV-crosslinked, electrospun PCL/aPLA-co-TMC composite polymer for tubular tissue engineering applications.

PubMed

Stefani, I; Cooper-White, J J

2016-05-01

Cardiovascular diseases remain the largest cause of death worldwide, and half of these deaths are the result of failure of the vascular system. Tissue engineering promises to provide new, and potentially more effective therapeutic strategies to replace damaged or degenerated vessels with functional vessels. However, these engineered vessels have substantial performance criteria, including vessel-like tubular shape, structure and mechanical property slate. Further, whether implanted without or with prior in vitro culture, such tubular scaffolds must provide a suitable environment for cell adhesion and growth and be of sufficient porosity to permit cell colonization. This study investigates the fabrication of slowly degradable, composite tubular polymer scaffolds made from polycaprolactone (PCL) and acrylated l-lactide-co-trimethylene carbonate (aPLA-co-TMC). The addition of acrylate groups permits the 'in-process' formation of crosslinks between aPLA-co-TMC chains during electrospinning of the composite system, exemplifying a novel process to produce multicomponent, elastomeric electrospun polymer scaffolds. Although PCL and aPLA-co-TMC were miscible in a co-solvent, a criteria for electrospinning, due to thermodynamic incompatibility of the two polymers as melts, solvent evaporation during electrospinning drove phase separation of these two systems, producing 'core-shell' fibres, with the core being composed of PCL, and the shell of crosslinked elastomeric aPLA-co-TMC. The resulting elastic fibrous scaffolds displayed burst pressures and suture retention strengths comparable with human arteries. Cytocompatibility testing with human mesenchymal stem cells confirmed adhesion to, and proliferation on the three-dimensional fibrous network, as well as alignment with highly-organized fibres. This new processing methodology and resulting mechanically-robust composite scaffolds hold significant promise for tubular tissue engineering applications. Autologous small diameter blood vessel grafts are unsuitable solutions for vessel repair. Engineered solutions such as tubular biomaterial scaffolds however have substantial performance criteria to meet, including vessel-like tubular shape, structure and mechanical property slate. We detail herein an innovative methodology to co-electrospin and 'in-process' crosslink composite mixtures of Poly(caprolactone) and a newly synthesised acrylated-Poly(lactide-co-trimethylene-carbonate) to create elastomeric, core-shell nanofibrous porous scaffolds in a one-step process. This novel composite system can be used to make aligned scaffolds that encourage stem cell adhesion, growth and morphological control, and produce robust tubular scaffolds of tunable internal diameter and wall thickness that possess mechanical properties approaching those of native vessels, ideal for future applications in the field of vessel tissue engineering. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Unconstrained Recovery Characterization of Shape-Memory Polymer Networks for Cardiovascular Applications

PubMed Central

Yakacki, Christopher M.; Shandas, Robin; Lanning, Craig; Rech, Bryan; Eckstein, Alex; Gall, Ken

2009-01-01

Shape-memory materials have been proposed in biomedical device design due to their ability to facilitate minimally invasive surgery and recover to a predetermined shape in-vivo. Use of the shape-memory effect in polymers is proposed for cardiovascular stent interventions to reduce the catheter size for delivery and offer highly controlled and tailored deployment at body temperature. Shape-memory polymer networks were synthesized via photopolymerization of tert-butyl acrylate and poly (ethylene glycol) dimethacrylate to provide precise control over the thermomechanical response of the system. The free recovery response of the polymer stents at body temperature was studied as a function of glass transition temperature (Tg), crosslink density, geometrical perforation, and deformation temperature, all of which can be independently controlled. Room temperature storage of the stents was shown to be highly dependent on Tg and crosslink density. The pressurized response of the stents is also demonstrated to depend on crosslink density. This polymer system exhibits a wide range of shape-memory and thermomechanical responses to adapt and meet specific needs of minimally invasive cardiovascular devices. PMID:17296222

Three-Dimensional-Moldable Nanofiber-Reinforced Transparent Composites with a Hierarchically Self-Assembled "Reverse" Nacre-like Architecture.

PubMed

Biswas, Subir K; Sano, Hironari; Shams, Md Iftekhar; Yano, Hiroyuki

2017-09-06

Achieving a structural hierarchy and a uniform nanofiller dispersion simultaneously remains highly challenging for obtaining a robust polymer nanocomposite of immiscible components. In this study, a remarkably facile Pickering emulsification approach is developed to fabricate hierarchical composites of immiscible acrylic polymer and native cellulose nanofibers by taking advantage of the dual role of the nanofibers as both emulsion stabilizer and polymer reinforcement. The composites feature a unique "reverse" nacre-like microstructure reinforced with a well-dispersed two-tier hierarchical nanofiber network, leading to a synergistic high strength, modulus, and toughness (20, 50, and 53 times that of neat polymer, respectively), high optical transparency (89%), high flexibility, and a drastically low thermal expansion (13 ppm K -1 , 1/15th of the neat polymer). The nanocomposites have a three-dimensional-shape moldability, also their surface can be patterned with micro/nanoscale features with high fidelity by in situ compression molding, making them attractive as the substrate for flexible displays, smart contact lens devices, and photovoltaics. The Pickering emulsification approach should be broadly applicable for the fabrication of novel functional materials of various immiscible components.

Large accumulation of micro-sized synthetic polymer particles in the sea surface microlayer.

PubMed

Song, Young Kyoung; Hong, Sang Hee; Jang, Mi; Kang, Jung-Hoon; Kwon, Oh Youn; Han, Gi Myung; Shim, Won Joon

2014-08-19

Determining the exact abundance of microplastics on the sea surface can be susceptible to the sampling method used. The sea surface microlayer (SML) can accumulate light plastic particles, but this has not yet been sampled. The abundance of microplastics in the SML was evaluated off the southern coast of Korea. The SML sampling method was then compared to bulk surface water filtering, a hand net (50 μm mesh), and a Manta trawl net (330 μm mesh). The mean abundances were in the order of SML water > hand net > bulk water > Manta trawl net. Fourier transform infrared spectroscopy (FTIR) identified that alkyds and poly(acrylate/styrene) accounted for 81 and 11%, respectively, of the total polymer content of the SML samples. These polymers originated from paints and the fiber-reinforced plastic (FRP) matrix used on ships. Synthetic polymers from ship coatings should be considered to be a source of microplastics. Selecting a suitable sampling method is crucial for evaluating microplastic pollution.

Enhanced mechanical properties of low-surface energy thin films by simultaneous plasma polymerization of fluorine and epoxy containing polymers

NASA Astrophysics Data System (ADS)

Karaman, Mustafa; Uçar, Tuba

2016-01-01

Thin films of poly(2,2,3,4,4,4 hexafluorobutyl acrylate-glycidyl methacrylate) (P(HFBA-GMA) were deposited on different surfaces using an inductively coupled RF plasma reactor. Fluorinated polymer was used to impart hydrophobicity, whereas epoxy polymer was used for improved durability. The deposition at a low plasma power and temperature was suitable for the functionalization of fragile surfaces such as textile fabrics. The coated rough textile surfaces were found to be superhydrophobic with water contact angles greater than 150° due to the high retention of long fluorinated side chains. The hydrophobicity of the surfaces was observed to be stable after many exposures to ultrasonification tests, which is attributed to the mechanical durability of the films due to their epoxide functionality. FTIR and XPS analyses of the deposited films confirmed that the epoxide functionality of the polymers increased with increasing glycidyl methacrylate fraction in the reactor inlet. The modulus and hardness values of the films also increase with increasing epoxide functionality.

A Facile and General Approach to Recoverable High-Strain Multishape Shape Memory Polymers.

PubMed

Li, Xingjian; Pan, Yi; Zheng, Zhaohui; Ding, Xiaobin

2018-03-01

Fabricating a single polymer network with no need to design complex structures to achieve an ideal combination of tunable high-strain multiple-shape memory effects and highly recoverable shape memory property is a great challenge for the real applications of advanced shape memory devices. Here, a facile and general approach to recoverable high-strain multishape shape memory polymers is presented via a random copolymerization of acrylate monomers and a chain-extended multiblock copolymer crosslinker. As-prepared shape memory networks show a large width at the half-peak height of the glass transition, far wider than current classical multishape shape memory polymers. A combination of tunable high-strain multishape memory effect and as high as 1000% recoverable strain in a single chemical-crosslinking network can be obtained. To the best of our knowledge, this is the first thermosetting material with a combination of highly recoverable strain and tunable high-strain multiple-shape memory effects. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Local Dynamics of Acid- and Ion-containing Copolymer Melts

NASA Astrophysics Data System (ADS)

Winey, Karen; Middleton, Robert; Tarver, Jacob; Tyagi, Madhusudan; Soles, Christopher; Frischknecht, Amalie

Interest in acid- and ion-containing polymers arises in part from applications as single-ion conductors for selectively transporting a counter ion for battery applications. Structurally, the low dielectric constant of organic polymers and strong ionic interactions leads to ionic aggregation. Here the polymer backbone motion was investigated through quasi-elastic neutron scattering measurements (QENS) and compared with fully atomistic molecular dynamic simulations of precise poly(ethylene-acrylic acid) copolymers and their ionomers (pxAA-y%Li). The effect of carbon spacer length (x =9, 15, 21) between the acid groups and the degree of neutralization (y) with Li on PE backbone dynamics were considered. Systematic slowing in chain dynamics were observed with increasing neutralization where polymer dynamics appear constrained due to anchoring effects. Simulations provide complementary viewpoints indicating a gradient in chain dynamics as a distance away from acid groups. These results indicate that the addition of pendant acid groups inhibit typical PE backbone motion and the neutralized forms strongly suppress the fraction of mobile PE chain.

The influence of polymer topology on pharmacokinetics: differences between cyclic and linear PEGylated poly(acrylic acid) comb polymers.

PubMed

Chen, Bo; Jerger, Katherine; Fréchet, Jean M J; Szoka, Francis C

2009-12-16

Water-soluble polymers for the delivery of chemotherapeutic drugs passively target solid tumors as a consequence of reduced renal clearance and the enhanced permeation and retention (EPR) effect. Elimination of the polymers in the kidney occurs due to filtration through biological nanopores with a hydrodynamic diameter comparable to the polymer. Therefore we have investigated chemical features that may broadly be grouped as "molecular architecture" such as: molecular weight, chain flexibility, number of chain ends and branching, to learn how they impact polymer elimination. In this report we describe the synthesis of four pairs of similar molecular weight cyclic and linear polyacrylic acid polymers grafted with polyethylene glycol (23, 32, 65, 114 kDa) with low polydispersities using ATRP and "click" chemistry. The polymers were radiolabeled with (125)I and their pharmacokinetics and tissue distribution after intravenous injection were determined in normal and C26 adenocarcinoma tumored BALB/c mice. Cyclic polymers above the renal threshold of 30 kDa had a significantly longer elimination time (between 10 and 33% longer) than did the comparable linear polymer (for the 66 kDa cyclic polymer, t(1/2,beta)=35+/-2 h) and a greater area under the serum concentration versus time curve. This resulted in a greater tumor accumulation of the cyclic polymer than the linear polymer counterpart. Thus water-soluble cyclic comb polymers join a growing list of polymer topologies that show greatly extended circulation times compared to their linear counterparts and provide alternative polymer architecture for use as drug carriers.

The Influence of Polymer Topology on Pharmacokinetics: Differences Between Cyclic and Linear PEGylated Poly(acrylic Acid) Comb Polymers

PubMed Central

Chen, Bo; Jerger, Katherine; Fréchet, Jean M. J.; Szoka, Francis C.

2009-01-01

Water-soluble polymers for the delivery of chemotherapeutic drugs passively target solid tumors as a consequence of reduced renal clearance and the enhanced permeation and retention (EPR) effect. Elimination of the polymers in the kidney occurs due to filtration through biological nanopores with a hydrodynamic diameter comparable to the polymer. Therefore we have investigated chemical features that may broadly be grouped as “molecular architecture” such as: molecular weight, chain flexibility, number of chain ends and branching, to learn how they impact polymer elimination. In this report we describe the synthesis of four pairs of similar molecular weight cyclic and linear polyacrylic acid polymers grafted with polyethylene glycol (23, 32, 65, 114 kDa) with low polydispersities using ATRP and “click” chemistry. The polymers were radiolabeled with 125I and their pharmacokinetics and tissue distribution after intravenous injection were determined in normal and C26 adenocarcinoma tumored BALB/c mice. Cyclic polymers above the renal threshold of 30kDa had a significantly longer elimination time (between 10 to 33 % longer) than did the comparable linear polymer (for the 66 kDa cyclic polymer, t1/2, β= 35 ± 2 h) and a greater area under the serum concentration time curve. This resulted in a greater tumor accumulation of the cyclic polymer than the linear polymer counterpart. Thus water-soluble cyclic comb polymers join a growing list of polymer topologies that show greatly extended circulation times compared to their linear counterparts and provide alternative polymer architecture for use as drug carriers. PMID:19465070

Superabsorbent Polymers: An Idea Whose Time Has Come

NASA Astrophysics Data System (ADS)

Buchholz, Fredric L.

1996-06-01

Superabsorbent polymers are cross-linked polyelectrolytes. Because of their ionic nature and interconnected structure, they absorb large quantities of water and other aqueous solutions without dissolving. This makes them ideally suited as absorbents of body fluids in many personal care products sold today, including baby diapers, adult incontinence products, and feminine napkins. Several emerging applications are also described. A simple laboratory preparation of partially neutralized, cross-linked poly(acrylic acid) is given along with test methods suitable for measuring the absorption capacity of the product. Experiments are described that demonstrate the ability of a swelling gel to perform work, and the ability of a gel to exclude macromolecular solutes from diffusing into its porous, cross-linked structure.

Photonic porous silicon as a pH sensor

PubMed Central

2014-01-01

Chronic wounds do not heal within 3 months, and during the lengthy healing process, the wound is invariably exposed to bacteria, which can colonize the wound bed and form biofilms. This alters the wound metabolism and brings about a change of pH. In this work, porous silicon photonic films were coated with the pH-responsive polymer poly(2-diethylaminoethyl acrylate). We demonstrated that the pH-responsive polymer deposited on the surface of the photonic film acts as a barrier to prevent water from penetrating inside the porous matrix at neutral pH. Moreover, the device demonstrated optical pH sensing capability visible by the unaided eye. PMID:25177227

Puncture-Healing Thermoplastic Resin Carbon-Fiber-Reinforced Composites

NASA Technical Reports Server (NTRS)

Grimsley, Brian W. (Inventor); Gordon, Keith L. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor); Siochi, Emilie J. (Inventor)

2015-01-01

A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

Puncture-Healing Thermoplastic Resin Carbon-Fiber Reinforced Composites

NASA Technical Reports Server (NTRS)

Gordon, Keith L. (Inventor); Siochi, Emilie J. (Inventor); Grimsley, Brian W. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor)

2017-01-01

A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

Taichi-inspired rigid-flexible coupling cellulose-supported solid polymer electrolyte for high-performance lithium batteries

PubMed Central

Zhang, Jianjun; Yue, Liping; Hu, Pu; Liu, Zhihong; Qin, Bingsheng; Zhang, Bo; Wang, Qingfu; Ding, Guoliang; Zhang, Chuanjian; Zhou, Xinhong; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

2014-01-01

Inspired by Taichi, we proposed rigid-flexible coupling concept and herein developed a highly promising solid polymer electrolyte comprised of poly (ethylene oxide), poly (cyano acrylate), lithium bis(oxalate)borate and robust cellulose nonwoven. Our investigation revealed that this new class solid polymer electrolyte possessed comprehensive properties in high mechanical integrity strength, sufficient ionic conductivity (3 × 10−4 S cm−1) at 60°C and improved dimensional thermostability (up to 160°C). In addition, the lithium iron phosphate (LiFePO4)/lithium (Li) cell using such solid polymer electrolyte displayed superior rate capacity (up to 6 C) and stable cycle performance at 80°C. Furthermore, the LiFePO4/Li battery could also operate very well even at an elevated temperature of 160°C, thus improving enhanced safety performance of lithium batteries. The use of this solid polymer electrolyte mitigates the safety risk and widens the operation temperature range of lithium batteries. Thus, this fascinating study demonstrates a proof of concept of the use of rigid-flexible coupling solid polymer electrolyte toward practical lithium battery applications with improved reliability and safety. PMID:25183416

Piezoelectric Nanoparticle-Polymer Composite Materials

NASA Astrophysics Data System (ADS)

McCall, William Ray

Herein we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be synthesized and fabricated into complex microstructures using sugar-templating methods or optical printing techniques. Stretchable foams with excellent tunable piezoelectric properties are created by incorporating sugar grains directly into polydimethylsiloxane (PDMS) mixtures containing barium titanate (BaTiO3 -- BTO) nanoparticles and carbon nanotubes (CNTs), followed by removal of the sugar after polymer curing. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio and the electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs. User defined 2D and 3D optically printed piezoelectric microstructures are also fabricated by incorporating BTO nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate (PEGDA) and exposing to digital optical masks that can be dynamically altered. Mechanical-to-electrical conversion efficiency of the optically printed composite is enhanced by chemically altering the surface of the BTO nanoparticles with acrylate groups which form direct covalent linkages with the polymer matrix under light exposure. Both of these novel materials should find exciting uses in a variety of applications including energy scavenging platforms, nano- and microelectromechanical systems (NEMS/MEMS), sensors, and acoustic actuators.

Effect of degree of crosslinking and polymerization of 3D printable polymer/ionic liquid composites on performance of stretchable piezoresistive sensors

NASA Astrophysics Data System (ADS)

Lee, Jeongwoo; Faruk Emon, Md Omar; Vatani, Morteza; Choi, Jae-Won

2017-03-01

Ionic liquid (IL)/polymer composites (1-ethyl-3-methyl-imidazolium tetrafluoroborate (EMIMBF4)/2-[[(butylamino)carbonyl]oxy]ethyl acrylate (BACOEA)) were fabricated to use as sensing materials for stretchable piezoresistive tactile sensors. The detectability of the IL/polymer composites was enhanced because the ionic transport properties of EMIMBF4 in the composites were improved by the synergic actions between the coordinate sites generated by the local motion of BACOEA chain segments under enough activation energy. The performance of the piezoresistive sensors was investigated with the degree of crosslinking and polymerization of the IL/polymer composites. As the compressive strain was increased, the distance between two electrodes decreased, and the motion of polymer chains and IL occurred, resulting in a decrease in the electrical resistance of the sensors. We have confirmed that the sensitivity of the sensors are affected by the degree of crosslink and polymerization of the IL/polymer composites. In addition, all of the materials (skins, sensing material, and electrode) used in this study are photo-curable, and thus the stretchable piezoresistive tactile sensors can be successfully fabricated by 3D printing.

Removal of heavy metals from waste streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spence, M.D.; Kozaruk, J.M.; Melvin, M.

1988-07-19

A method for removing heavy metals from effluent water is described comprising performing sequentially the following steps: (a) adding from 7-333 ppm of an anionic surfactant to the effluent water to provide coagulatable heavy metal ion; (b) adjusting the effluent water pH to within the range of 8 to 10, (c) providing from 10-200 ppm of a cationic coagulant to coagulate the heavy metal ion, (d) providing from 0.3 to 5.0 ppm of a polymeric flocculant whereby a heavy metal containing floc is formed for removal from the effluent water, and, (e) then removing the floc from the effluent water,more » wherein the anionic surfactant is sodium lauryl ether sulfate. The cationic coagulant is selected from the group consisting of diallyl dimethylammonium chloride polymer, epichlorohydrin dimethylamine polymer, ethylene amine polymer, polyaluminum chloride, and alum; and the flocculant is an acrylamide/sodium acrylate copolymer having an RSV greater than 23.« less

Grafting of 2 (2-hydroxy-5-vinylphenyl) 2H-benzotriazole onto polymers with aliphatic groups. Synthesis and polymerization of 2 (2-hydroxy-5-isopropenylphenyl) 2H-benzotriazole and a new synthesis of 2 (2-hydroxy-5-vinylphenyl) 2H-benzotriazole

NASA Technical Reports Server (NTRS)

Pradellok, W.; Nir, Z.; Vogl, O.

1981-01-01

Successful grafting of 2(2-hydroxy-5-vinylphenyl)2H-benzotriazole onto saturated aliphatic C-H groups of polymers has been accomplished. When the grafting reaction was carried out in chlorobenzene at 150 C = 160 C with di-tertiarybutylperoxide as the grafting initiator, grafts as high as 20 percent - 30 percent at a grafting efficiency of 50 percent and 80 percent have readily been obtained. The grafting reaction was carried out in tubes sealed under high vacuum since trace amounts of oxygen cause complete inhibition of the grafting reaction by the phenolic monomer. On a variety of different polymers including atactic polypropylene, ethylene/vinyl acetate copolymer, poly(methyl methacrylate), poly(butyl acrylate), and polycarbonate were used.

Electrowetting of Weak Polyelectrolyte-Coated Surfaces.

PubMed

Sénéchal, Vincent; Saadaoui, Hassan; Rodriguez-Hernandez, Juan; Drummond, Carlos

2017-05-23

Polymer coatings are commonly used to modify interfacial properties like wettability, lubrication, or biocompatibility. These properties are determined by the conformation of polymer molecules at the interface. Polyelectrolytes are convenient elementary bricks to build smart materials, given that polyion chain conformation is very sensitive to different environmental variables. Here we discuss the effect of an applied electric field on the properties of surfaces coated with poly(acrylic acid) brushes. By combining atomic force microscopy, quartz crystal microbalance, and contact angle experiments, we show that it is possible to precisely tune polyion chain conformation, surface adhesion, and surface wettability using very low applied voltages if the polymer grafting density and environmental conditions (pH and ionic strength) are properly formulated. Our results indicate that the effective ionization degree of the grafted weak polyacid can be finely controlled with the externally applied field, with important consequences for the macroscopic surface properties.

Synthesis of Hydroxy-Terminated Dinitropropyl Acrylate Polymers and Improved Characterization of Hydroxy-Terminated Prepolymers

DTIC Science & Technology

1983-03-01

Carbonate GPC Gel Permeation Chromatography HEDS Hydroxyethyl Disulfide HPLC High Pressure Liquid Chromatography NMIM N-methyl imidazole NPGA Neopentyl... analysis and intrinsic viscosity determination by a capillary viscometry shows promise as a reliable approach for the determination of the molecular...more reliable and meaningful data than GPC analysis alone. 3.2.3 Determination of Number Average Functionality of Prepolymer of fp < 2.0 The number

Photooxidative degradation of clear ultraviolet absorbing acrylic copolymer surfaces

NASA Technical Reports Server (NTRS)

Gupta, A.; Liang, R. H.; Vogl, O.; Pradellok, W.; Huston, A. L.; Scott, G. W.

1983-01-01

Photodegradation of copolymer of methyl methacrylate and 2(2'-hydroxy 5'vinyl-phenyl) 2H-benzotriazole has been investigated in order to determine the changes in the chemical composition of the surface of the copolymer on photooxidation. An electronic energy transfer mechanism has been postulated in order to interpret the observed photochemical changes in the polymer. Preliminary examination of the photophysical properties of the chromophore provides support for such a mechanism.

Fluorogel elastomers with tunable transparency, elasticity, shape-memory, and antifouling properties

DOE PAGES

Yao, Xi; Dunn, Stuart S.; Kim, Philseok; ...

2014-03-18

In this study, omniphobic fluorogel elastomers were prepared by photocuring perfluorinated acrylates and a perfluoropolyether crosslinker. By tuning either the chemical composition or the temperature that control the crystallinity of the resulting polymer chains, a broad range of optical and mechanical properties of the fluorogel can be achieved. After infusing with fluorinated lubricants, the fluorogels showed excellent resistance to wetting by various liquids and anti-biofouling behavior, while maintaining cytocompatiblity.

Polyacrylic acid polymer brushes as substrates for the incorporation of anthraquinone derivatives. Unprecedented application of decorated polymer brushes on organocatalysis

NASA Astrophysics Data System (ADS)

Ruiz-Muelle, Ana Belén; Contreras-Cáceres, Rafael; Oña-Burgos, Pascual; Rodríguez-Dieguez, Antonio; López-Romero, Juan Manuel; Fernández, Ignacio

2018-01-01

The synthesis of amino-terminated anthraquinone derivatives and their incorporation onto polymer brushes for the fabrication of silicon-based nanometric functional coatings are described for the first time. The general process involves the covalent grafting of anthraquinone 1 onto two different polymer-brushes by amidation reactions. They are composed by amino- and carboxy-terminated poly(acrylic acid) chains (PAA-NH2- and PAA-COOH, respectively) tethered by one end to an underlying silicon oxide (SiO2) substrate in a polymer brush configuration. A third substrate is fabricated by UV induced hydrosilylation reaction using undecenoic acid as adsorbate on hydrogen-terminated Si(111) surfaces. One- and two-dimensional nuclear magnetic resonance (NMR), FT-IR, MS and X-ray diffraction (XRD) were used to characterize anthraquinone 1. Ellipsometric and X-ray photoelectron spectroscopy (XPS) measurements demonstrated the presence of the polymer brushes on the silicon wafers, and atomic force microscopy (AFM) was used to study its surface morphology. The covalent linkage between anthraquinone and polymer brushes was proven by XPS and confocal fluorescence microscopy. The resulting surfaces were assayed in the heterogenous organocatalytic transformation of (1H)-indole into 3-benzyl indole with moderate yields but with high recyclability.

Thiomers: a new generation of mucoadhesive polymers.

PubMed

Bernkop-Schnürch, Andreas

2005-11-03

Thiolated polymers or designated thiomers are mucoadhesive basis polymers, which display thiol bearing side chains. Based on thiol/disulfide exchange reactions and/or a simple oxidation process disulfide bonds are formed between such polymers and cysteine-rich subdomains of mucus glycoproteins building up the mucus gel layer. Thiomers mimic therefore the natural mechanism of secreted mucus glycoproteins, which are also covalently anchored in the mucus layer by the formation of disulfide bonds-the bridging structure most commonly encountered in biological systems. So far the cationic thiomers chitosan-cysteine, chitosan-thiobutylamidine as well as chitosan-thioglycolic acid and the anionic thiomers poly(acylic acid)-cysteine, poly(acrylic acid)-cysteamine, carboxy-methylcellulose-cysteine and alginate-cysteine have been generated. Due to the immobilization of thiol groups on mucoadhesive basis polymers, their mucoadhesive properties are 2- up to 140-fold improved. The higher efficacy of this new generation of mucoadhesive polymers in comparison to the corresponding unmodified mucoadhesive basis polymers could be verified via various in vivo studies on various mucosal membranes in different animal species and in humans. The development of first commercial available products comprising thiomers is in progress. Within this review an overview of the mechanism of adhesion and the design of thiomers as well as delivery systems comprising thiomers and their in vivo performance is provided.

Assembly of polythiophenes on responsive polymer microgels for the highly selective detection of ammonia gas

DOE PAGES

Chang, Aiping; Peng, Yahui; Li, Zezhou; ...

2016-04-05

For this study, a class of smart composite materials based on the assembly of conjugated polymers on responsive polymer microgels has been prepared. We have chosen poly(3-((2-(2-methoxyethoxy)ethoxy)methyl)-thiophene) as the model conjugated polymer and an ammonia-responsive microgel of phenoxazinium-functionalized poly(N-isopropylacrylamide-co-propargyl acrylate) as the model template. Under this design, the composite materials can combine the electrical conductivity of the conjugated polymers and the ammonia recognisability of the ammonia-responsive polymer microgels; the cooperation of these properties allows the reversible control of electrical conductivity by ammonia gas. Those composite materials can not only adapt to ammonia gas, but also convert changes in the concentrationmore » of ammonia into conductance, allowing the electrical detection of ammonia gas with high selectivity. This makes the composite materials different from the conductive polymer platforms reported previously, which may also respond to non-ammonia gases and the response induced by non-ammonia gases is close to that induced by ammonia gas. Using these composite materials as sensing materials for the electrical detection of ammonia gas, the detection limit can reach as low as 1.1 ppb. Finally, these features enable their use for the electrical detection of ammonia in breath.« less

Assembly of polythiophenes on responsive polymer microgels for the highly selective detection of ammonia gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Aiping; Peng, Yahui; Li, Zezhou

For this study, a class of smart composite materials based on the assembly of conjugated polymers on responsive polymer microgels has been prepared. We have chosen poly(3-((2-(2-methoxyethoxy)ethoxy)methyl)-thiophene) as the model conjugated polymer and an ammonia-responsive microgel of phenoxazinium-functionalized poly(N-isopropylacrylamide-co-propargyl acrylate) as the model template. Under this design, the composite materials can combine the electrical conductivity of the conjugated polymers and the ammonia recognisability of the ammonia-responsive polymer microgels; the cooperation of these properties allows the reversible control of electrical conductivity by ammonia gas. Those composite materials can not only adapt to ammonia gas, but also convert changes in the concentrationmore » of ammonia into conductance, allowing the electrical detection of ammonia gas with high selectivity. This makes the composite materials different from the conductive polymer platforms reported previously, which may also respond to non-ammonia gases and the response induced by non-ammonia gases is close to that induced by ammonia gas. Using these composite materials as sensing materials for the electrical detection of ammonia gas, the detection limit can reach as low as 1.1 ppb. Finally, these features enable their use for the electrical detection of ammonia in breath.« less

Acid-Group-Content-Dependent Proton Conductivity Mechanisms at the Interlayer of Poly(N-dodecylacrylamide-co-acrylic acid) Copolymer Multilayer Nanosheet Films.

PubMed

Sato, Takuma; Tsukamoto, Mayu; Yamamoto, Shunsuke; Mitsuishi, Masaya; Miyashita, Tokuji; Nagano, Shusaku; Matsui, Jun

2017-11-14

The effect of the content of acid groups on the proton conductivity at the interlayer of polymer-nanosheet assemblies was investigated. For that purpose, amphiphilic poly(N-dodecylacrylamide-co-acrylic acid) copolymers [p(DDA/AA)] with varying contents of AA were synthesized by free radical polymerization. Surface pressure (π)-area (A) isotherms of these copolymers indicated that stable polymer monolayers are formed at the air/water interface for AA mole fraction (n) ≤ 0.49. In all cases, a uniform dispersion of the AA groups in the polymer monolayer was observed. Subsequently, polymer monolayers were transferred onto solid substrates using the Langmuir-Blodgett (LB) technique. X-ray diffraction (XRD) analyses of the multilayer films showed strong Bragg diffraction peaks, suggesting a highly uniform lamellar structure for the multilayer films. The proton conductivity of the multilayer films parallel to the direction of the layer planes were measured by impedance spectroscopy, which revealed that the conductivity increased with increasing values of n. Activation energies for proton conduction of ∼0.3 and 0.42 eV were observed for n ≥ 0.32 and n = 0.07, respectively. Interestingly, the proton conductivity of a multilayer film with n = 0.19 did not follow the Arrhenius equation. These results were interpreted in terms of the average distance between the AA groups (l AA ), and it was concluded that, for n ≥ 0.32, an advanced 2D hydrogen bonding network was formed, while for n = 0.07, l AA is too long to form such hydrogen bonding networks. The l AA for n = 0.19 is intermediate to these extremes, resulting in the formation of hydrogen bonding networks at low temperatures, and disruption of these networks at high temperatures due to thermally induced motion. These results indicate that a high proton conductivity with low activation energy can be achieved, even under weakly acidic conditions, by arranging the acid groups at an optimal distance.

Wear characteristics of current aesthetic dental restorative CAD/CAM materials: two-body wear, gloss retention, roughness and Martens hardness.

PubMed

Mörmann, Werner H; Stawarczyk, Bogna; Ender, Andreas; Sener, Beatrice; Attin, Thomas; Mehl, Albert

2013-04-01

This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group. Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million loadings, 49N at 1.7Hz; 3000 thermocycles 5/50°C). Each of the 11 groups consisted of 12 specimens and 12 enamel antagonists. Quantitative analysis of wear was carried out with a 3D-surface analyser. Gloss and roughness measurements were evaluated using a glossmeter and an inductive surface profilometer before and after abrasive toothbrushing of machine-polished specimens. Additionally Martens hardness was measured. Statistically significant differences were calculated with one-way ANOVA (analysis of variance). Statistically significant differences were found for two-body wear, gloss, surface roughness and hardness. Zirconium dioxide ceramics showed no material wear and low wear of the enamel antagonist. Two-body wear of CAD/CAM-silicate and -lithium disilicate ceramics, -hybrid ceramics and -nanocomposite as well as direct nanocomposite did not differ significantly from that of human enamel. Temporary polymers showed significantly higher material wear than permanent materials. Abrasive toothbrushing significantly reduced gloss and increased roughness of all materials except zirconium dioxide ceramics. Gloss retention was highest with zirconium dioxide ceramics, silicate ceramics, hybrid ceramics and nanocomposites. Temporary polymers showed least gloss retention. Martens hardness differed significantly among ceramics, between ceramics and composites, and between resin composites and acrylic block materials as well. All permanent aesthetic CAD/CAM block materials tested behave similarly or better with respect to two-body wear and toothbrushing wear than human enamel, which is not true for temporary polymer CAD/CAM block materials. Ceramics show the best gloss retention compared to hybrid ceramics, composites and acrylic polymers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bonding durability between acrylic resin adhesives and titanium with surface preparations.

PubMed

Yanagida, Hiroaki; Minesaki, Yoshito; Matsumura, Kousuke; Tanoue, Naomi; Muraguchi, Koichi; Minami, Hiroyuki

2017-01-31

The purpose of the present study was to evaluate the efficacy of pretreatment on the bonding durability between titanium casting and two acrylic adhesives. Cast titanium disk specimens treated with four polymer-metal bonding systems as follow: 1) air-abraded with 50-70 μm alumina, 2) 1)+Alloy Primer, 3) 1)+M.L. Primer and 4) tribochemical silica/silane coating system (Rocatec System). The specimens were bonded with M bond or Super-bond C&B adhesive. The shear bond strengths were determined before and after thermocycling (20,000 cycles). The surface characteristics after polishing, and for the 1) and 4) preparations were determined. The bond strengths for all combinations significantly decreased after thermocycling. The combination of Super-bond C&B adhesive and 2) led to significantly higher bond strength than the other preparations after thermocycling. The maximum height of the profile parameters for the polishing group was lower than other preparations.

Designed drug-release systems having various breathable polyurethane film-backed hydrocolloid acrylated adhesive layers for moisture healing.

PubMed

Chang, Ching-Hsien; Liu, Hsia-Wei; Huang, Ching-Cheng

2014-01-01

A series of designed drug-release systems were prepared and established for clear moisture healing. These systems were designed to have an interpenetrating polymer network (IPN) structure, which contained a breathable polyurethane film, hydrocolloidlayer, and polyacrylate adhesive layer. Breathable polyurethane film (2000 g/m(2)/24 hr) with high moisture permeability was employed as a base for new drug-release systems or wound dressings. All drug-release systems having a polyurethane film-backed hydrocolloid acrylated adhesive layer showed an increase of water uptakes with increasing time. After 114 hours, high water uptakes of drug-release systems with 20% hydrocolloid components were observed in the values of 160, 1100, and 1870% for different additional hydrocolloid components of carboxymethylcellulose, sodium alginate, and carbomer U10, respectively. New drug-release systems of polyurethane film-backed hydrocolloid/adhesive layers could be designed and established for wound care managements.

Carbon nanotubes and carbon onions for modification of styrene-acrylate copolymer based nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merijs-Meri, Remo; Zicans, Janis; Ivanova, Tatjana

2014-05-15

Styrene acrylate polymer (SAC) nanocomposites with various carbon nanofillers (multiwalled carbon nanotubes MWCNTs and onion like carbon OLC) are manufactured by means of latex based routes. Concentration of the carbon nanofillers is changed in a broad interval starting from 0.01 up to 10 wt. %. Elastic, dielectric and electromagnetic properties of SAC nanocomposites are investigated. Elastic modulus, electrical conductivity and electromagnetic radiation absorption of the investigated SAC nanocomposites increase along with rising nanofiller content. The effect of the addition of anisometric MWCNTs on the elastic properties of the composite is higher than in the case of the addition of OLC.more » Higher electrical conductivity of the OLC containing nanocomposites is explained with the fact that reasonable agglomeration of the nanofiller can promote the development of electrically conductive network. Efficiency of the absorption of electromagnetic radiation depends on the development of conductive network within the SAC matrix.« less

Novel carboxy functionalized sol-gel precursors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolter, H.; Storch, W.; Gellermann, C.

1996-12-31

A novel family of inorganic-organic copolymers (ORMOCER`s) derived from urethane- and thioether(meth)acrylate alkoxysilanes has been successfully exploited for a variety of diverse applications. In order to widen the range of applications an additional functionality (carboxy group) has been incorporated int his silane type. Conventional sol-gel processing facilitates the formation of an inorganic Si-O-Si-network via hydrolysis and polycondensation reactions of alkoxysilyl moieties and in addition, the (meth)acrylate groups are available for radically induced polymerization to obtain a complementary organic polymer structure. The presence of a carboxy group would appear to have great potential for a range of diverse areas of application,more » such as an internal catalyst for the sol-gel process, complexation of elements such as Zr and Ti, increasing the adhesion to various substrates and modification of solubility. A number of novel silanes and their syntheses will be described in this paper.« less

Preparation and Properties of a Novel Semi-IPN Slow-Release Fertilizer with the Function of Water Retention.

PubMed

Xiang, Yang; Ru, Xudong; Shi, Jinguo; Song, Jiang; Zhao, Haidong; Liu, Yaqing; Guo, Dongdong; Lu, Xin

2017-12-20

A new semi-interpenetrating polymer network (semi-IPN) slow-release fertilizer (SISRF) with water absorbency, based on the kaolin-g-poly(acrylic acid-co-acrylic amide) (kaolin-g-P(AA-co-AM)) network and linear urea-formaldehyde oligomers (UF), was prepared by solution polymerization. Nutrients phosphorus and potassium were supplied by adding dipotassium hydrogen phosphate during the preparation process. The structure and properties of SISRF were characterized by various characterization methods. SISRF showed excellent water absorbency of 68 g g -1 in tap water. The slow-release behavior of nutrients and water-retention capacity of SISRF were also measured. Meanwhile, the swelling kinetics was well described by a pseudo-second-order kinetics model. Results suggested the formation of SISRF with simultaneously good slow-release and water-retention capacity, which was expected to apply in modern agriculture and horticulture.

Combinatorial Methodology for Screening Selectivity in Polymeric Pervaporation Membranes.

PubMed

Godbole, Rutvik V; Ma, Lan; Doerfert, Michael D; Williams, Porsche; Hedden, Ronald C

2015-11-09

Combinatorial methodology is described for rapid screening of selectivity in polymeric pervaporation membrane materials for alcohol-water separations. The screening technique is demonstrated for ethanol-water separation using a model polyacrylate system. The materials studied are cross-linked random copolymers of a hydrophobic comonomer (n-butyl acrylate, B) and a hydrophilic comonomer (2-hydroxyethyl acrylate, H). A matrix of materials is prepared that has orthogonal variations in two key variables, H:B ratio and cross-linker concentration. For mixtures of ethanol and water, equilibrium selectivities and distribution coefficients are obtained by combining swelling measurements with high-throughput HPLC analysis. Based on the screening results, two copolymers are selected for further study as pervaporation membranes to quantify permeability selectivity and the flux of ethanol. The screening methodology described has good potential to accelerate the search for new membrane materials, as it is adaptable to a broad range of polymer chemistries.

Segregation of mass at the periphery of N -isopropylacrylamide-co-acrylic-acid microgels at high temperatures

DOE PAGES

Hyatt, John S.; Do, Changwoo; Hu, Xiaobo; ...

2015-09-29

Here, we investigate poly(N-isopropylacrylamide) (pNIPAM) microgels randomly copolymerized with large mol % of protonated acrylic acid (AAc), finding that above the lower critical solution temperature the presence of the acid strongly disrupts pNIPAM's collapse, leading to unexpected new behavior at high temperatures. We see a dramatic increase in the ratio between the radius of gyration and the hydrodynamic radius above the theoretical value for homogeneous spheres, and a corresponding increase of the network length scale, which we attribute to the presence of a heterogeneous polymer distribution that forms due to frustration of pNIPAM's coil-to-globule transition by the AAc. Finally, wemore » analyze this phenomenon using a Debye-Bueche-like scattering contribution as opposed to the Lorentzian term often used, interpreting the results in terms of mass segregation at the particle periphery.« less

Synthesis and characterization of functionalized methacrylates for coatings and biomedical applications

NASA Astrophysics Data System (ADS)

Shemper, Bianca Sadicoff

The research presented in this dissertation involves the design of polymers for biomaterials and for coatings applications. The development of non-wettable, hard UV-curing, or reactive coatings is discussed. The biomaterials section involves the syntheses of linear and star-like polymers of the functionalized monomer poly(propylene glycol) monomethacrylate (PPGM) via atom transfer radical polymerization (ATRP) (Chapter II). Its copolymerization with a perfluoroalkyl ethyl methacrylate monomer (1H,1H,2H,2H-heptadecafluorodecyl methacrylate) and the syntheses of linear and star-like amphiphilic copolymers containing the fluorinated monomer and poly(ethyleneglycol) methyl ether methacrylate (MPEGMA) are discussed in Chapter III. The four-arm amphiphilic block copolymer obtained showed unique associative properties leading to micellization in selective solvents. Chapter IV includes research involving the design of films with low surface energy by incorporating fluorine into the polymer. The synthesis, characterization and polymerization of a perfluoroalkylether-substituted methacrylic acid (C8F7) are discussed, and the properties of coatings obtained after its photopolymerization on different substrates are evaluated to confirm formation of low-surface energy polymeric coatings. Subsequently, hard coatings based on methyl (alpha-hydroxymethyl)acrylate (MHMA) were prepared via photopolymerization using UV-light. Firstly, mechanistic investigations into the photopolymerization behavior of (alpha-hydroxymethyl)acrylates (RHMA's) are reported (Chapter V). RHMA derivatives were photopolymerized with various multifunctional acrylates and methacrylates and the effect of crosslinker type and degree of functionality on photopolymerization rates and conversions was investigated. Then, in Chapter VI the synthesis of a series of new crosslinkers is described and their photopolymerization kinetics was investigated in bulk. The effect of these novel crosslinkers on the photopolymerization kinetics and coatings properties of MHMA systems is then shown in Chapter VII. This chapter also includes the effect of the presence of synthetic clay in these systems and the preparation of nanocomposite-based films. The final chapter of this dissertation involves the design of reactive coatings for biomedical applications. The syntheses and characterization of novel functionalized methacrylates containing succinimide ester groups susceptible to derivatization with amine-containing species were accomplished. Photopolymerization of these monomers led to formation of hydrogels and derivatization of the hydrogel surfaces with the tripeptide RGD (arginine-glycine-aspartic acid) was successfully achieved.

A Facile in Situ and UV Printing Process for Bioinspired Self-Cleaning Surfaces

PubMed Central

González Lazo, Marina A.; Katrantzis, Ioannis; Dalle Vacche, Sara; Karasu, Feyza; Leterrier, Yves

2016-01-01

A facile in situ and UV printing process was demonstrated to create self-cleaning synthetic replica of natural petals and leaves. The process relied on the spontaneous migration of a fluorinated acrylate surfactant (PFUA) within a low-shrinkage acrylated hyperbranched polymer (HBP) and its chemical immobilization at the polymer-air interface. Dilute concentrations of 1 wt. % PFUA saturated the polymer-air interface within 30 min, leading to a ten-fold increase of fluorine concentration at the surface compared with the initial bulk concentration and a water contact angle (WCA) of 108°. A 200 ms flash of UV light was used to chemically crosslink the PFUA at the HBP surface prior to UV printing with a polydimethylsiloxane (PDMS) negative template of red and yellow rose petals and lotus leaves. This flash immobilization hindered the reverse migration of PFUA within the bulk HBP upon contacting the PDMS template, and enabled to produce texturized surfaces with WCA well above 108°. The synthetic red rose petal was hydrophobic (WCA of 125°) and exhibited the adhesive petal effect. It was not superhydrophobic due to insufficient concentration of fluorine at its surface, a result of the very large increase of the surface of the printed texture. The synthetic yellow rose petal was quasi-superhydrophobic (WCA of 143°, roll-off angle of 10°) and its self-cleaning ability was not good also due to lack of fluorine. The synthetic lotus leaf did not accurately replicate the intricate nanotubular crystal structures of the plant. In spite of this, the fluorine concentration at the surface was high enough and the leaf was superhydrophobic (WCA of 151°, roll-off angle below 5°) and also featured self-cleaning properties. PMID:28773860

Electron Beam Curing of Composite Positive Electrode for Li-Ion Battery

DOE PAGES

Du, Zhijia; Janke, C. J.; Li, Jianlin; ...

2016-10-12

We have successfully used electron beam cured acrylated polyurethanes as novel binders for positive electrodes for Li-ion batteries. Furthermore, the cross-linked polymer after electron beam curing coheres active materials and carbon black together onto Al foil. Electrochemical tests demonstrate the stability of the polymer at a potential window of 2.0 V–4.6 V. The electrode is found to have similar voltage profiles and charge-transfer resistance compared to the conventional electrode using polyvinylidene fluoride as the binder. Finally, when the electrode is tested in full Li-ion cells, they exhibit excellent cycling performance, indicating promising use for this new type of binder inmore » commercial Li-ion batteries in the future.« less

One-Pot Automated Synthesis of Quasi Triblock Copolymers for Self-Healing Physically Crosslinked Hydrogels.

PubMed

Voorhaar, Lenny; De Meyer, Bernhard; Du Prez, Filip; Hoogenboom, Richard

2016-10-01

The preparation of physically crosslinked hydrogels from quasi ABA-triblock copolymers with a water-soluble middle block and hydrophobic end groups is reported. The hydrophilic monomer N-acryloylmorpholine is copolymerized with hydrophobic isobornyl acrylate via a one-pot sequential monomer addition through reversible addition fragmentation chain-transfer (RAFT) polymerization in an automated parallel synthesizer, allowing systematic variation of polymer chain length and hydrophobic-hydrophilic ratio. Hydrophobic interactions between the outer blocks cause them to phase-separate into larger hydrophobic domains in water, forming physical crosslinks between the polymers. The resulting hydrogels are studied using rheology and their self-healing ability after large strain damage is shown. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dialysis membrane for separation on microchips

DOEpatents

Singh, Anup K [San Francisco, CA; Kirby, Brian J [San Francisco, CA; Shepodd, Timothy J [Livermore, CA

2010-07-13

Laser-induced phase-separation polymerization of a porous acrylate polymer is used for in-situ fabrication of dialysis membranes inside glass microchannels. A shaped 355 nm laser beam is used to produce a porous polymer membrane with a thickness of about 15 .mu.m, which bonds to the glass microchannel and forms a semi-permeable membrane. Differential permeation through a membrane formed with pentaerythritol triacrylate was observed and quantified by comparing the response of the membrane to fluorescein and fluorescently tagging 200 nm latex microspheres. Differential permeation was observed and quantified by comparing the response to rhodamine 560 and lactalbumin protein in a membrane formed with SPE-methylene bisacrylamide. The porous membranes illustrate the capability for the present technique to integrate sample cleanup into chip-based analysis systems.

Constitutive Parameter Measurement Using Double Ridge Waveguide

DTIC Science & Technology

2013-03-01

different microwave absorbers. The sample constructed by AFRL is a polymer known commercially as VeroP and was fabricated in a Polyjet 3D printer . The...local 3D printer resources. The acrylic was able to fit similarly to the AFRL sample. The absorber material was formed using laser cut plastic as a...samples. During the sample fabrication process, the 3D printer from Air Force Institute of Technology (AFIT) was used to verify the sample size. The

CAD/CAM Handbook for Polymer Composite Reliability. Volume II. Figures and Tables.

DTIC Science & Technology

1983-03-01

for 177*C (350°F) service temperature epoxy resins ....................... 149 5-2 Repeat structure for 50:50 mole % isoamyl acrylate = neopentyl...and measured Tg (X’s) for Hercules 3501-5 epoxy resin (see Table 1-6 and Ref. 44) ................. 162 Chapter 6 6-1 Tensile response of C2F...173 6-12 Calculated (X) and experiment (.) effects of moisture on T_ of six cured epoxy resins (3501-5, 3501-6, 5208

Theoretical study of chain transfer to solvent reactions of alkyl acrylates.

PubMed

Moghadam, Nazanin; Srinivasan, Sriraj; Grady, Michael C; Rappe, Andrew M; Soroush, Masoud

2014-07-24

This computational and theoretical study deals with chain transfer to solvent (CTS) reactions of methyl acrylate (MA), ethyl acrylate (EA), and n-butyl acrylate (n-BA) self-initiated homopolymerization in solvents such as butanol (polar, protic), methyl ethyl ketone (MEK) (polar, aprotic), and p-xylene (nonpolar). The results indicate that abstraction of a hydrogen atom from the methylene group next to the oxygen atom in n-butanol, from the methylene group in MEK, and from a methyl group in p-xylene by a live polymer chain are the most likely mechanisms of CTS reactions in MA, EA, and n-BA. Energy barriers and molecular geometries of reactants, products, and transition states are predicted. The sensitivity of the predictions to three hybrid functionals (B3LYP, X3LYP, and M06-2X) and three different basis sets (6-31G(d,p), 6-311G(d), and 6-311G(d,p)) is investigated. Among n-butanol, sec-butanol, and tert-butanol, tert-butanol has the highest CTS energy barrier and the lowest rate constant. Although the application of the conductor-like screening model (COSMO) does not affect the predicted CTS kinetic parameter values, the application of the polarizable continuum model (PCM) results in higher CTS energy barriers. This increase in the predicted CTS energy barriers is larger for butanol and MEK than for p-xylene. The higher rate constants of chain transfer to n-butanol reactions compared to those of chain transfer to MEK and p-xylene reactions suggest the higher CTS reactivity of n-butanol.

In vivo evaluation of thiolated poly(acrylic acid) as a drug absorption modulator for MRP2 efflux pump substrates.

PubMed

Greindl, Melanie; Föger, Florian; Hombach, Juliane; Bernkop-Schnürch, Andreas

2009-08-01

Recently, several polymers have been reported to modulate drug absorption by inhibition of intestinal efflux pumps such as multidrug resistance proteins (MRPs) and P-glycoprotein (P-gp). The aim of the present study was to evaluate the efficiency of thiolated poly(acrylic acid) (PAA-Cys) to act as a drug absorption modulator for MRP2 efflux pump substrates in vivo, using sulforhodamine 101 as representative MRP2 substrate. In vitro, the permeation-enhancing effect of unmodified PAA and PAA(250)-Cys(,) displaying 580 micromol free thiol groups per gram polymer, was evaluated by using freshly excised rat intestinal mucosa mounted in Ussing-type chambers. In comparison to that of the buffer control, the sulforhodamine 101 transport in the presence of 0.5% unmodified PAA(250) and 0.5% (w/v) PAA(250)-Cys was 1.3- and 4.0-fold improved, respectively. In vivo, sulforhodamine 101 solutions containing 4% (w/v) unmodified PAA(250) or 4% (w/v) thiolated PAA(250) were orally given to rats. The PAA(250)-Cys solution increased the area under the plasma concentration-time curve (AUC(0-12)) of sulforhodamine 101 3.8-fold in comparison to control and 2.2-fold in comparison to unmodified PAA(250). This in vivo study revealed that PAA(250)-Cys significantly increased the oral bioavailability of MRP2 substrate sulforhodamine 101.

Development of nitroxide radicals-containing polymer for scavenging reactive oxygen species from cigarette smoke

NASA Astrophysics Data System (ADS)

Yoshitomi, Toru; Kuramochi, Kazuhiro; Binh Vong, Long; Nagasaki, Yukio

2014-06-01

We developed a nitroxide radicals-containing polymer (NRP), which is composed of poly(4-methylstyrene) possessing nitroxide radicals as a side chain via amine linkage, to scavenge reactive oxygen species (ROS) from cigarette smoke. In this study, the NRP was coated onto cigarette filters and its ROS-scavenging activity from streaming cigarette smoke was evaluated. The intensity of electron spin resonance signals of the NRP in the filter decreased after exposure to cigarette smoke, indicating consumption of nitroxide radicals. To evaluate the ROS-scavenging activity of the NRP-coated filter, the amount of peroxy radicals in an extract of cigarette smoke was measured using UV-visible spectrophotometry and 1,1-diphenyl-2-picrylhydrazyl (DPPH). The absorbance of DPPH at 517 nm decreased with exposure to cigarette smoke. When NRP-coated filters were used, the decrease in the absorbance of DPPH was prevented. In contrast, both poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters, which have no nitroxide radical, did not show any effect, indicating that the nitroxide radicals in the NRP scavenge the ROS in cigarette smoke. As a result, the extract of cigarette smoke passed through the NRP-coated filter has a lower cellular toxicity than smoke passed through poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters. Accordingly, NRP is a promising material for ROS scavenging from cigarette smoke.

Cytocompatible antifungal acrylic resin containing silver nanoparticles for dentures

PubMed Central

Acosta-Torres, Laura Susana; Mendieta, Irasema; Nuñez-Anita, Rosa Elvira; Cajero-Juárez, Marcos; Castaño, Víctor M

2012-01-01

Background Inhibition of Candida albicans on denture resins could play a significant role in preventing the development of denture stomatitis. The safety of a new dental material with antifungal properties was analyzed in this work. Methods Poly(methyl methacrylate) [PMMA] discs and PMMA-silver nanoparticle discs were formulated, with the commercial acrylic resin, Nature-CrylTM, used as a control. Silver nanoparticles were synthesized and characterized by ultraviolet-visible spectroscopy, dispersive Raman spectroscopy, and transmission electron microscopy. The antifungal effect was assessed using a luminescent microbial cell viability assay. Biocompatibility tests were carried out using NIH-3T3 mouse embryonic fibroblasts and a Jurkat human lymphocyte cell line. Cells were cultured for 24 or 72 hours in the presence or absence of the polymer formulations and analyzed using three different tests, ie, cellular viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell proliferation by enzyme-linked immunosorbent assay BrdU, and genomic DNA damage (Comet assay). Finally, the samples were evaluated mechanically, and the polymer-bearing silver nanoparticles were analyzed microscopically to evaluate dispersion of the nanoparticles. Results The results show that PMMA-silver nanoparticle discs significantly reduce adherence of C. albicans and do not affect metabolism or proliferation. They also appear not to cause genotoxic damage to cells. Conclusion The present work has developed a new biocompatible antifungal PMMA denture base material. PMID:22969297

New inorganic/organic copolymers (ORMOCER{reg_sign}s) for dental applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolter, H.; Storch, W.; Ott, H.

1994-12-31

Urethane and thioether (meth)acrylate alkoxysilanes have been used, as sol-gel precursors, for the preparation of a special family of inorganic/organic copolymers (ORMOCER{reg_sign}s). The basic silane type offers the following structural and synthetic possibilities for modifying the properties of the resulting copolymers: variation of the number of alkoxy groups, combination with other, different, sol-gel precursors, variation of the number of attached (meth)acrylate groups (1--5), and variation within the molecular segment (kind, structure and length) connecting the inorganic with the organic polymer structure. To achieve the additional organic polymer structure in the cured copolymer the use of different radically induced polymerization approachesmore » (UV-, visible light-, thermal- and redox induced) is possible. Taking the incorporation of fillers into account, the Young`s modulus of these copolymers is adjustable in a range of 1--17,000 MPa, and the thermal expansion coefficient in a range of 17--250{center_dot}10{sup {minus}6}{center_dot}K{sup {minus}1} (5--50 C). Other advantages are the low shrinkage (1--2,8 vol.-%), the high flexural strength (up to 160 MPa), and the high abrasion resistance. This new copolymer type seems to have significant potential for medical applications, especially as dental filling material to replace the currently used controversial amalgam fillings.« less

Synthesis of silica coated zinc oxide–poly(ethylene-co-acrylic acid) matrix and its UV shielding evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramasamy, Mohankandhasamy; Kim, Yu Jun; Gao, Haiyan

Graphical abstract: - Highlights: • Well layer thickness controlled silica shell was made on ZnO nanoparticles. • PEAA, an interfacial agent is used to make nanocomposite–polymer matrix by twin-screw extruder. • Si-ZnO/PEAA matrix is highly stable and UV protective as compared to ZnO/PEAA matrix. • Nanoparticle embedded polymer matrix is suggested to make UV shielding fabrics with Nylon4. - Abstract: Silica coated zinc oxide nanoparticles (Si-ZnO NPs) (7 nm thick) were synthesized successfully and melt blended with poly(ethylene-co-acrylic acid) (PEAA resin) to improving ultraviolet (UV) shielding of zinc oxide nanoparticles (ZnO NPs). The photostability of both the ZnO NPs andmore » Si-ZnO NPs were analyzed by the difference in photoluminescence (PL) and by methylene blue (MB) degradation. Photo-degradation studies confirmed that Si-ZnO NPs are highly photostable compared to ZnO NPs. The melt blended matrices were characterized by field emission scanning electron microscopy interfaced with energy dispersive X-ray spectroscopy (FE-SEM-EDX). The UV shielding property was analyzed from the transmittance spectra of UV–visible (UV–vis) spectroscopy. The results confirmed fine dispersion of thick Si-ZnO NPs in the entire resin matrix. Moreover, the Si-ZnO/PEAA showed about 97% UV shielding properties than the ZnO/PEAA.« less

A Facile Strategy for Catalyst Separation and Recycling Suitable for ATRP of Hydrophilic Monomers Using a Macroligand.

PubMed

Jiang, Xiaowu; Wu, Jian; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

2016-01-01

How to simply and efficiently separate and recycle catalyst has still been a constraint for the wide application of atom transfer radical polymerization (ATRP), especially for the polymerization systems with hydrophilic monomers because the polar functional groups may coordinate with transition metal salts, resulting in abundant catalyst residual in the resultant water-soluble polymers. In order to overcome this problem, a latent-biphasic system is developed, which can be successfully used for ATRP catalyst separation and recycling in situ for various kinds of hydrophilic monomers for the first time, such as poly(ethylene glycol) monomethyl ether methacrylate (PEGMA), 2-hydroxyethyl methacrylate (HEMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), N,N-dimethyl acrylamide (DMA), and N-isopropylacrylamide (NIPAM). Herein, random copolymer of octadecyl acrylate (OA), MA-Ln (2-(bis(pyridin-2-ylmethyl)amino)ethyl acrylate), and POA-ran-P(MA-Ln) is designed as the macroligand, and heptane/ethanol is selected as the biphasic solvent. Copper(II) bromide (CuBr2 ) is employed as the catalyst, PEG-bound 2-bromo-2-methylpropanoate (PEG350 -Br) as the water-soluble ATRP initiator and 2,2'-azobis(isobutyronitrile) (AIBN) as the azo-initiator to establish an ICAR (initiators for continuous activator regeneration) ATRP system. Importantly, well-defined water-soluble polymers are obtained even though the recyclable catalyst is used for sixth times. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Engineering single-molecule, nanoscale, and microscale bio-functional materials via click chemistry

NASA Astrophysics Data System (ADS)

Daniele, Michael Angelo-Anthony

To expand the design envelope and supplement the materials library available to biomaterials scientists, the copper(I)-catalyzed azide-alkyne cycloaddition (CuCAAC) was explored as a route to design, synthesize and characterize bio-functional small-molecules, nanoparticles, and microfibers. In each engineered system, the use of click chemistry provided facile, bio-orthogonal control for materials synthesis; moreover, the results provided a methodology and more complete, fundamental understanding of the use of click chemistry as a tool for the synergy of biotechnology, polymer and materials science. Fluorophores with well-defined photophysical characteristics (ranging from UV to NIR fluorescence) were used as building blocks for small-molecule, fluorescent biosensors. Fluorophores were paired to exhibit fluorescence resonant energy transfer (FRET) and used to probe the metabolic activity of carbazole 1,9a-dioxygenase (CARDO). The FRET pair exhibited a significant variation in PL response with exposure to the lysate of Pseudomonas resinovorans CA10, an organism which can degrade variants of both the donor and acceptor fluorophores. Nanoparticle systems were modified via CuCAAC chemistry to carry affinity tags for CARDO and were subsequently utilized for affinity based bioseparation of CARDO from crude cell lysate. The enzymes were baited with an azide-modified carbazolyl-moiety attached to a poly(propargyl acrylate) nanoparticle. Magnetic nanocluster systems were also modified via CuCAAC chemistry to carry fluorescent imaging tags. The iron-oxide nanoclusters were coated with poly(acrylic acid-co-propargyl acrylate) to provide a clickable surface. Ultimately, alternate Cu-free click chemistries were utilized to produce biohybrid microfibers. The biohybrid microfibers were synthesized under benign photopolymerization conditions inside a microchannel, allowing the encapsulation of viable bacteria. By adjusting pre-polymer solutions and laminar flow rates within the microchannel, the morphology, hydration, and thermal properties of the fibers were easily tuned. The methodology produced hydrogel fibers that sustained viable cells as demonstrated by the encapsulation and subsequent proliferation of Bacillus cereus and Escherichia coli communities.

Feasibility of Crosslinked Acrylic Shape Memory Polymer for a Thrombectomy Device

PubMed Central

Muschenborn, Andrea D.; Hearon, Keith; Volk, Brent L.; Conway, Jordan W.; Maitland, Duncan J.

2014-01-01

Purpose To evaluate the feasibility of utilizing a system of SMP acrylates for a thrombectomy device by determining an optimal crosslink density that provides both adequate recovery stress for blood clot removal and sufficient strain capacity to enable catheter delivery. Methods Four thermoset acrylic copolymers containing benzylmethacrylate (BzMA) and bisphenol A ethoxylate diacrylate (Mn~512, BPA) were designed with differing thermomechanical properties. Finite element analysis (FEA) was performed to ensure that the materials were able to undergo the strains imposed by crimping, and fabricated devices were subjected to force-monitored crimping, constrained recovery, and bench-top thrombectomy. Results Devices with 25 and 35 mole% BPA exhibited the highest recovery stress and the highest brittle response as they broke upon constrained recovery. On the contrary, the 15 mole % BPA devices endured all testing and their recovery stress (5 kPa) enabled successful bench-top thrombectomy in 2/3 times, compared to 0/3 for the devices with the lowest BPA content. Conclusion While the 15 mole% BPA devices provided the best trade-off between device integrity and performance, other SMP systems that offer recovery stresses above 5 kPa without increasing brittleness to the point of causing device failure would be more suitable for this application. PMID:25414549

Liquid electrolyte-free cylindrical Al polymer capacitor review: Materials and characteristics

NASA Astrophysics Data System (ADS)

Yoo, Jeeyoung; Kim, Jaegun; Kim, Youn Sang

2015-06-01

The manufacturing methods for liquid electrolyte-free Al polymer capacitors are introduced by using new materials like novel oxidants, separators and negative current collectors. The Al polymer capacitor is constructed by an Al foil as an anode, Al2O3 as a dielectric, and poly(3, 4-ethylenedioxythiophene) (PEDOT) as a cathode. There are also various synthetic methods of 3, 4-ethylenedioxythiophene (EDOT) and the chemical polymerization of PEDOT from EDOT using iron benzenesulfonate as a new oxidant and dopant. Furthermore, various cathodic current collectors such as conventional Al foils, carbon and titanium dioxide deposited on Al foils or substrates, as well as various separators with manila-esparto paper and synthetic fibers (series of acryl, PET, etc.) are studied. The Al polymer capacitors with the newly introduced oxidant (iron benzenesulfonate), separator (aramid based synthetic fibers) and current collector (TiO2) exhibit considerably enhanced capacitance values and the extremely low resistance (7 mΩ), so there is low power consumption and high reliability. Additionally, the newly developed Al polymer capacitor is guaranteed for 5,000 h at 125 °C, which means there is a long life time operation over ∼ 5 × 106 h at 65 °C.

Responsive copolymers for enhanced petroleum recovery. Annual report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCormick, C.; Hester, R.

1994-08-01

A coordinated research program involving synthesis, characterization, and rheology has been undertaken to develop advanced polymer system which should be significantly more efficient than polymers presently used for mobility control and conformance. Unlike the relatively inefficient, traditional EOR polymers, these advanced polymer systems possess microstructural features responsive to temperature, electrolyte concentration, and shear conditions. Contents of this report include the following chapters. (1) First annual report responsive copolymers for enhanced oil recovery. (2) Copolymers of acrylamide and sodium 3-acrylamido-3-methylbutanoate. (3) Terpolymers of NaAMB, Am, and n-decylacrylamide. (4) Synthesis and characterization of electrolyte responsive terpolymers of acrylamide, N-(4-butyl)phenylacrylamide, and sodium acrylate,more » sodium-2-acrylamido-2-methylpropanesulphonate or sodium-3-acrylamido-3-methylbutanoate. (5) Synthesis and solution properties of associative acrylamido copolymers with pyrensulfonamide fluorescence labels. (6) Photophysical studies of the solution behavior of associative pyrenesulfonamide-labeled polyacrylamides. (7) Ampholytic copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate with [2-(acrylamido)-2-methypropyl]trimethylammonium chloride. (8) Ampholytic terpolymers of acrylamide with sodium 2-acrylamido-2-methylpropanesulphoante and 2-acrylamido-2-methylpropanetrimethyl-ammonium chloride and (9) Polymer solution extensional behavior in porous media.« less

Hyperbranched-polymer dispersed nanocomposite volume gratings for holography and diffractive optics

NASA Astrophysics Data System (ADS)

Tomita, Yasuo; Takeuchi, Shinsuke; Oyaizu, Satoko; Urano, Hiroshi; Fukamizu, Taka-aki; Nishimura, Naoya; Odoi, Keisuke

2016-10-01

We review our experimental investigations of photopolymerizable nanoparticle-polymer composites (NPCs) for holography and diffractive optics. Various types of hyperbranched polymer (HBP) were systhesized and used as transporting organic nanoparticles. These HBPs include hyperbranched poly(ethyl methacrylate) (HPEMA), hyperbranched polystyrene (HPS) and hyperbranched triazine/aromatic polymer units (HTA) whose refractive indices are 1.51, 1.61 and 1.82, respectively. Each HBP was dispersed in (meth)acrylate monomer whose refractive index was so chosen that a refractive index difference between HBP and the formed polymer was large. Such monomer-HBP syrup was mixed with a titanocene photoinitiator for volume holographic recording in the green. We used a two-beam interference setup to write an unslanted transmission volume grating at grating spacing of 1 μm and at a wavelength of 532 nm. It is shown that NPC volume gratings with the saturated refractive index modulation amplitudes as large as 0.008, 0.004 and 0.02 can be recorded in NPCs incorporated with HPEMA, HPS and HTA at their optimum concentrations of 34, 34 and 25 vol.%, respectively. We show the usefulness of HBP-dispersed NPC volume gratings for holographic applications such as holographic data storage and diffractive optical devices.

Chemical and Temperature Effects on Diffusion in a Model Polymer/Nanoparticle Composite

NASA Astrophysics Data System (ADS)

Janes, Dustin; Durning, Christopher

Polymers and inks used in medical devices may be strengthened with nanoparticle fillers, so an understanding of how they may affect the release of residuals and additives via diffusion will help modernize biocompatibility testing. Transport of small molecules in polymers with increasing volume fraction of impermeable nanoparticles is often poorly predicted by the simple Maxwell model for heterogeneous media. In this presentation we will examine two diffusant classes, only one of which possesses hydrogen bonding interactions with the nanoparticle surface. Since similar reductions in mutual diffusion coefficients were observed in both cases we attribute the enhancement of the ''blocking effect'' in nanocomposites to a reduction in polymer mobility in the interfacial volume near the nanoparticle. The temperature and penetrant concentration dependence of the diffusion coefficients were examined in the context of a Vrentas-Duda free volume model that includes a thermally activated prefactor. While data obtained for rubbery poly(methyl acrylate) clearly obeys the expected Arrhenius scaling with EA = 11 kJ/mol, results for films containing d = 14 nm spherical silica nanoparticles do not, providing more evidence that polymer free volume is perturbed in unexpected ways even for conceptually simple systems. National Science Foundation IGERT Program, Pall Corporation.

Role of the Strength of Drug-Polymer Interactions on the Molecular Mobility and Crystallization Inhibition in Ketoconazole Solid Dispersions.

PubMed

Mistry, Pinal; Mohapatra, Sarat; Gopinath, Tata; Vogt, Frederick G; Suryanarayanan, Raj

2015-09-08

The effects of specific drug-polymer interactions (ionic or hydrogen-bonding) on the molecular mobility of model amorphous solid dispersions (ASDs) were investigated. ASDs of ketoconazole (KTZ), a weakly basic drug, with each of poly(acrylic acid) (PAA), poly(2-hydroxyethyl methacrylate) (PHEMA), and polyvinylpyrrolidone (PVP) were prepared. Drug-polymer interactions in the ASDs were evaluated by infrared and solid-state NMR, the molecular mobility quantified by dielectric spectroscopy, and crystallization onset monitored by differential scanning calorimetry (DSC) and variable temperature X-ray diffractometry (VTXRD). KTZ likely exhibited ionic interactions with PAA, hydrogen-bonding with PHEMA, and weaker dipole-dipole interactions with PVP. On the basis of dielectric spectroscopy, the α-relaxation times of the ASDs followed the order: PAA > PHEMA > PVP. In addition, the presence of ionic interactions also translated to a dramatic and disproportionate decrease in mobility as a function of polymer concentration. On the basis of both DSC and VTXRD, an increase in strength of interaction translated to higher crystallization onset temperature and a decrease in extent of crystallization. Stronger drug-polymer interactions, by reducing the molecular mobility, can potentially delay the crystallization onset temperature as well as crystallization extent.

Polymer excipients enable sustained drug release in low pH from mechanically strong inorganic geopolymers.

PubMed

Jämstorp, Erik; Yarra, Tejaswi; Cai, Bing; Engqvist, Håkan; Bredenberg, Susanne; Strømme, Maria

2012-01-01

Improving acid resistance, while maintaining the excellent mechanical stability is crucial in the development of a sustained and safe oral geopolymer dosage form for highly potent opioids. In the present work, commercially available Methacrylic acid-ethyl acrylate copolymer, Polyethylene-glycol (PEG) and Alginate polymer excipients were included in dissolved or powder form in geopolymer pellets to improve the release properties of Zolpidem, herein acting as a model drug for the highly potent opioid Fentanyl. Scanning electron microscopy, compression strength tests and drug release experiments, in gastric pH 1 and intestinal pH 6.8 conditions, were performed. The polymer excipients, with an exception for PEG, reduced the drug release rate in pH 1 due to their ability to keep the pellets in shape, in combination with the introduction of an insoluble excipient, and thereby maintain a barrier towards drug diffusion and release. Neither geopolymer compression strength nor the release in pH 6.8 was considerably impaired by the incorporation of the polymer excipients. The geopolymer/polymer composites combine high mechanical strength and good release properties under both gastric and intestinal pH conditions, and are therefore promising oral dosage forms for sustained release of highly potent opioids.

Polymer Film Dewetting by Water/Surfactant/Good-Solvent Mixtures: A Mechanistic Insight and Its Implications for the Conservation of Cultural Heritage.

PubMed

Baglioni, Michele; Montis, Costanza; Chelazzi, David; Giorgi, Rodorico; Berti, Debora; Baglioni, Piero

2018-06-18

Aqueous nanostructured fluids (NSFs) have been proposed to remove polymer coatings from the surface of works of art; this process usually involves film dewetting. The NSF cleaning mechanism was studied using several techniques that were employed to obtain mechanistic insight on the interaction of a methacrylic/acrylic copolymer (Paraloid B72) film laid on glass surfaces and several NSFs, based on two solvents and two surfactants. The experimental results provide a detailed picture of the dewetting process. The gyration radius and the reduction of the T g of Paraloid B72 fully swollen in the two solvents is larger for propylene carbonate than for methyl ethyl ketone, suggesting higher mobility of polymer chains for the former, while a nonionic alcohol ethoxylate surfactant was more effective than sodium dodecylsulfate in favoring the dewetting process. FTIR 2D imaging showed that the dewetting patterns observed on model samples are also present on polymer-coated mortar tiles when exposed to NSFs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Accelerated Combinatorial High Throughput Star Polymer Synthesis via a Rapid One-Pot Sequential Aqueous RAFT (rosa-RAFT) Polymerization Scheme.

PubMed

Cosson, Steffen; Danial, Maarten; Saint-Amans, Julien Rosselgong; Cooper-White, Justin J

2017-04-01

Advanced polymerization methodologies, such as reversible addition-fragmentation transfer (RAFT), allow unprecedented control over star polymer composition, topology, and functionality. However, using RAFT to produce high throughput (HTP) combinatorial star polymer libraries remains, to date, impracticable due to several technical limitations. Herein, the methodology "rapid one-pot sequential aqueous RAFT" or "rosa-RAFT," in which well-defined homo-, copolymer, and mikto-arm star polymers can be prepared in very low to medium reaction volumes (50 µL to 2 mL) via an "arm-first" approach in air within minutes, is reported. Due to the high conversion of a variety of acrylamide/acrylate monomers achieved during each successive short reaction step (each taking 3 min), the requirement for intermediary purification is avoided, drastically facilitating and accelerating the star synthesis process. The presented methodology enables RAFT to be applied to HTP polymeric bio/nanomaterials discovery pipelines, in which hundreds of complex polymeric formulations can be rapidly produced, screened, and scaled up for assessment in a wide range of applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance comparison of hybrid resistive switching devices based on solution-processable nanocomposites

NASA Astrophysics Data System (ADS)

Rajan, Krishna; Roppolo, Ignazio; Bejtka, Katarzyna; Chiappone, Annalisa; Bocchini, Sergio; Perrone, Denis; Pirri, Candido Fabrizio; Ricciardi, Carlo; Chiolerio, Alessandro

2018-06-01

The present work compares the influence of different polymer matrices on the performance of planar asymmetric Resistive Switching Devices (RSDs) based on silver nitrate and Ionic Liquid (IL). PolyVinyliDene Fluoride-HexaFluoroPropylene (PVDF-HFP), PolyEthylene Oxide (PEO), PolyMethyl MethAcrylate (PMMA) and a blend of PVDF-HFP and PEO were used as matrices and compared. RSDs represent perhaps the most promising electron device to back the More than Moore development, and our approach through functional polymers enables low temperature processing and gives compatibility towards flexible/stretchable/wearable equipment. The switching mechanism in all the four sample families is explained by means of a filamentary conduction. A huge difference in the cyclability and the On/Off ratio is experienced when changing the active polymers and explained based on the polymer crystallinity degree and general morphology of the prepared nanocomposite. It is worth noting that all the RSDs discussed here present good switching behaviour with reasonable endurance. The current study displays one of the most cost-effective and effortless ways to produce an RSD based on solution-processable materials.

One-pot synthesis of redox-responsive polymers-coated mesoporous silica nanoparticles and their controlled drug release.

PubMed

Sun, Jiao-Tong; Piao, Ji-Gang; Wang, Long-Hai; Javed, Mohsin; Hong, Chun-Yan; Pan, Cai-Yuan

2013-09-01

A versatile one-pot strategy for the preparation of reversibly cross-linked polymer-coated mesoporous silica nanoparticles (MSNs) via surface reversible addition-fragmentation chain transfer (RAFT) polymerization is presented for the first time in this paper. The less reactive monomer oligo(ethylene glycol) acrylate (OEGA) and the more reactive cross-linker N,N'-cystaminebismethacrylamide (CBMA) are chosen to be copolymerized on the external surfaces of RAFT agent-functionalized MSNs to form the cross-linked polymer shells. Owing to the reversible cleavage and restoration of disulfide bonds via reduction/oxidation reactions, the polymer shells can control the on/off switching of the nanopores and regulate the drug loading and release. The redox-responsive release of doxorubicin (DOX) from this drug carrier is realized. The protein adsorption, in vitro cytotoxicity assays, and endocytosis studies demonstrate that this biocompatible vehicle is a potential candidate for delivering drugs. It is expected that this versatile grafting strategy may help fabricate satisfying MSN-based drug delivery systems for clinical application. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of pH-responsive β-CD-based star polymer and impact of its self-assembly behavior on pectinase activity.

PubMed

Hu, Dong; Yang, Hong; Liu, Jiangtao; Lei, Zhongli

2017-03-01

A novel type of pH-responsive star polymer based on β-cyclodextrin (β-CD) was synthesized and further covalently conjugated with enzyme. The impact of its self-assembly behavior on enzyme activity was investigated. In our design, azide containing the polymer (N 3 ) 7 -β-CD-(PtBA) 14 was synthesized via atom transfer radical polymerization of tert-butyl acrylate using (N 3 ) 7 -β-CD-(Br) 14 as the multifunctional initiator. The final product (N 3 ) 7 -β-CD-(PAA) 14 was obtained via hydrolysis and covalently conjugating pectinase onto pH-responsive polyacrylic acid (PAA) arms. PAA can change its conformation with the self-assembly by altered pH, leading its nanostructure into micellar nanoparticles in aqueous solution and further affecting the activity of immobilized pectinase. The results were proved by fluorescence spectroscopy and dynamic light scattering. This system proves that the activity of immobilized enzyme can be tailored predictably, and this pH-responsive polymer holds great potential for controllable delivery of enzymes. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

Injectable biocompatible and biodegradable pH-responsive hollow particle gels containing poly(acrylic acid): the effect of copolymer composition on gel properties.

PubMed

Halacheva, Silvia S; Adlam, Daman J; Hendow, Eseelle K; Freemont, Tony J; Hoyland, Judith; Saunders, Brian R

2014-05-12

The potential of various pH-responsive alkyl (meth)acrylate ester- and (meth)acrylic acid-based copolymers, including poly(methyl methacrylate-co-acrylic acid) (PMMA-AA) and poly(n-butyl acrylate-co-methacrylic acid) (PBA-MAA), to form pH-sensitive biocompatible and biodegradable hollow particle gel scaffolds for use in non-load-bearing soft tissue regeneration have been explored. The optimal copolymer design criteria for preparation of these materials have been established. Physical gels which are both pH- and redox-sensitive were formed only from PMMA-AA copolymers. MMA is the optimal hydrophobic monomer, whereas the use of various COOH-containing monomers, e.g., MAA and AA, will always induce a pH-triggered physical gelation. The PMMA-AA gels were prepared at physiological pH range from concentrated dispersions of swollen, hollow, polymer-based particles cross-linked with either cystamine (CYS) or 3,3'-dithiodipropionic acid dihydrazide (DTP). A linear relationship between particle swelling ratios, gel elasticity, and ductility was observed. The PMMA-AA gels with lower AA contents feature lower swelling ratios, mechanical strengths, and ductilities. Increasing the swelling ratio (e.g., through increasing AA content) decreased the intraparticle elasticity; however, intershell contact and gel elasticity were found to increase. The mechanical properties and performance of the gels were tuneable upon varying the copolymers' compositions and the structure of the cross-linker. Compared to PMMA-AA/CYS, the PMMA-AA/DTP gels were more elastic and ductile. The biodegradability and cytotoxicity of the new hollow particle gels were tested for the first time and related to their composition, mechanical properties, and morphology. The new PMMA-AA/CYS and PMMA-AA/DTP gels have shown good biocompatibility, biodegradability, strength, and interconnected porosity and therefore have good potential as a tissue repair agent.

Development of pH Sensitive Nanoparticles for Intestinal Drug Delivery Using Chemically Modified Guar Gum Co-Polymer.

PubMed

Varma, Vegesna Naga Sravan Kumar; Shivakumar, Hosakote Gurumalappa; Balamuralidhara, Veerna; Navya, Manne; Hani, Umme

2016-01-01

The aim of the research work was to chemically modify guargum (GG) as a pH sensitive co-polymer and formulating intestinal targeting ESO nanoparticles (NPs) using the synthesized co-polymer. Poly acrylamide-grafted-guar gum (PAAm-g-GG) co-polymer was synthesized by free radical polymerization. Chemical modification of PAAm-g-GG by alkaline hydrolysis results in formation of a pH-sensitive co-polymer. The effect of GG and acryl amide (AAm) on grafting was studied. Esomeprazole magnesium (ESO) loaded pH sensitive NPs were prepared by nano-emulsification polymer crosslinking method and characterized. Sixteen formulations were prepared and the concentration of process variables wasvaried to obtain nanoparticles of 200-600 nm. The NPs were found to be homogenous in size distribution. The encapsulation efficiency and drug loading ranged from 33.2% to 50.1% and 12.2% to 17.2% respectively. Particle size, encapsulation efficiency and drug loading increasedalong with co-polymer concentration. In-vitro release studies at pH 1.2 for 2 h, followed by pH 6.8 showed that environment pH significantly affected the drug release. SEM has shown that NPsare spherical with smooth surface. The pH sensitive PAAm-g-GGNPs resisted the initial release of the drug from the drug loaded NPs in acidic pH and delayed the release process to a longer period in alkaline environment.

Development of pH Sensitive Nanoparticles for Intestinal Drug Delivery Using Chemically Modified Guar Gum Co-Polymer

PubMed Central

Varma, Vegesna Naga Sravan Kumar; Shivakumar, Hosakote Gurumalappa; Balamuralidhara, Veerna; Navya, Manne; Hani, Umme

2016-01-01

The aim of the research work was to chemically modify guargum (GG) as a pH sensitive co-polymer and formulating intestinal targeting ESO nanoparticles (NPs) using the synthesized co-polymer. Poly acrylamide-grafted-guar gum (PAAm-g-GG) co-polymer was synthesized by free radical polymerization. Chemical modification of PAAm-g-GG by alkaline hydrolysis results in formation of a pH-sensitive co-polymer. The effect of GG and acryl amide (AAm) on grafting was studied. Esomeprazole magnesium (ESO) loaded pH sensitive NPs were prepared by nano-emulsification polymer crosslinking method and characterized. Sixteen formulations were prepared and the concentration of process variables wasvaried to obtain nanoparticles of 200-600 nm. The NPs were found to be homogenous in size distribution. The encapsulation efficiency and drug loading ranged from 33.2% to 50.1% and 12.2% to 17.2% respectively. Particle size, encapsulation efficiency and drug loading increasedalong with co-polymer concentration. In-vitro release studies at pH 1.2 for 2 h, followed by pH 6.8 showed that environment pH significantly affected the drug release. SEM has shown that NPsare spherical with smooth surface. The pH sensitive PAAm-g-GGNPs resisted the initial release of the drug from the drug loaded NPs in acidic pH and delayed the release process to a longer period in alkaline environment. PMID:27610149

Crosslinked, porous, polyacrylate beads

NASA Technical Reports Server (NTRS)

Rembaum, Alan (Inventor); Yen, Shiao-Ping Siao (Inventor); Dreyer, William J. (Inventor)

1976-01-01

Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

Crosslinked, porous, polyacrylate beads

NASA Technical Reports Server (NTRS)

Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

1977-01-01

Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree. C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

Effects of sterilization methods on key properties of specialty optical fibers used in medical devices

NASA Astrophysics Data System (ADS)

Stolov, Andrei A.; Slyman, Brian E.; Burgess, David T.; Hokansson, Adam S.; Li, Jie; Allen, R. Steve

2013-03-01

Optical fibers with different types of polymer coatings were exposed to three sterilization conditions: multiple autoclaving, treatment with ethylene oxide and treatment with gamma rays. Effects of different sterilization techniques on key optical and mechanical properties of the fibers are reported. The primary attention is given to behavior of the coatings in harsh sterilization environments. The following four coating/buffer types were investigated: (i) dual acrylate, (ii) polyimide, (iii) silicone/PEEK and (iv) fluoroacrylate hard cladding/ETFE.

Small, porous polyacrylate beads

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping Siao (Inventor); Rembaum, Alan (Inventor); Dreyer, William J. (Inventor)

1976-01-01

Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

A pH/enzyme-responsive polymer film consisting of Eudragit FS 30 D and arabinoxylane as a potential material formulation for colon-specific drug delivery system.

PubMed

Rabito, Mirela Fulgencio; Reis, Adriano Valim; Freitas, Adonilson dos Reis; Tambourgi, Elias Basile; Cavalcanti, Osvaldo Albuquerque

2012-01-01

Polymer film based on pH-dependent Eudragit FS 30 D acrylic polymer in association with arabinoxylane, a polysaccharide issued from gum psyllium, was produced by way of solvent casting. Physical-chemical characterization of the polymer film samples was performed by means of thermogravimetry (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Furthermore, water-equilibrium swelling index (I(s)) and weight loss of the films in KCl buffer solution of pH 1.2, in KH(2)PO(4) buffer solution of pH 5.0, or in KH(2)PO(4) buffer solution of pH 5.0 consisting of 4% enzyme Pectinex 3X-L (w/v) were also carried out for the film characterization. No chemical interactions between the Eudragit FS 30 D and the arabinoxylane polymer chains were evidenced, thus suggesting that the film-forming polymer structure was obtained from a physical mixture of both polymers. The arabinoxylane-loader films showed a more pronounced weight loss after their immersion in buffer solution containing enzyme Pectinex 3X-L. The introduction of the arabinoxylane makes the film more susceptible to undergo an enzymatic degradation. This meant that the enzyme-dependent propriety issued from the arabinoxylane has been imprinted into the film formulation. This type of polymer film is an interesting system for applications in colon-specific drug delivery system.

Comparison of selective flocculation of low grade goethitic iron ore fines using natural and synthetic polymers and a graft copolymer

NASA Astrophysics Data System (ADS)

Tudu, Kichakeswari; Pal, Sagar; Mandre, N. R.

2018-05-01

This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin (AP), poly acrylic acid (PAA), and a graft copolymer (AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction (XRD) and electron probe microanalysis (EPMA) techniques.

Oilfield flooding polymer

DOEpatents

Martin, Fred D.; Hatch, Melvin J.; Shepitka, Joel S.; Donaruma, Lorraine G.

1986-01-01

A monomer, polymers containing the monomer, and the use of the polymer in oilfield flooding is disclosed. The subject monomer is represented by the general formula: ##STR1## wherein: n is an integer from 0 to about 4; m is an integer from 0 to about 6; a is an integer equal to at least 1 except where m is equal to 0, a must equal 0 and where m is equal to 1, a must equal 0 or 1; p is an integer from 2 to about 10; b is an integer equal to at least 1 and is of sufficient magnitude that the ratio b/p is at least 0.2; and q is an integer from 0 to 2. The number of hydroxy groups in the monomer is believed to be critical, and therefore the sum of (a+b) divided by the sum (m+p) should be at least 0.2. The moieties linked to the acrylic nitrogen can be joined to provide a ringed structure.

Photo-induced Mass Transport through Polymer Networks

NASA Astrophysics Data System (ADS)

Meng, Yuan; Anthamatten, Mitchell

2014-03-01

Among adaptable materials, photo-responsive polymers are especially attractive as they allow for spatiotemporal stimuli and response. We have recently developed a macromolecular network capable of photo-induced mass transport of covalently bound species. The system comprises of crosslinked chains that form an elastic network and photosensitive fluorescent arms that become mobile upon irradiation. We form loosely crosslinked polymer networks by Michael-Addition between multifunctional thiols and small molecule containing acrylate end-groups. The arms are connected to the network by allyl sulfide, that undergoes addition-fragmentation chain transfer (AFCT) in the presence of free radicals, releasing diffusible fluorophore. The networks are loaded with photoinitiator to allow for spatial modulation of the AFCT reactions. FRAP experiments within bulk elastomers are conducted to establish correlations between the fluorophore's diffusion coefficient and experimental variables such as network architecture, temperature and UV intensity. Photo-induced mass transport between two contacted films is demonstrated, and release of fluorophore into a solvent is investigated. Spatial and temporal control of mass transport could benefit drug release, printing, and sensing applications.