Responses of Vascular Endothelial Cells to Photoembossed Topographies on Poly(Methyl Methacrylate) Films

PubMed Central

Qiu, Lin; Hughes-Brittain, Nanayaa F.; Bastiaansen, Cees W. M.; Peijs, Ton; Wang, Wen

2016-01-01

Failures of vascular grafts are normally caused by the lack of a durable and adherent endothelium covering the graft which leads to thrombus and neointima formation. A promising approach to overcome these issues is to create a functional, quiescent monolayer of endothelial cells on the surface of implants. The present study reports for the first time on the use of photoembossing as a technique to create polymer films with different topographical features for improved cell interaction in biomedical applications. For this, a photopolymer is created by mixing poly(methyl methacrylate) (PMMA) and trimethylolpropane ethoxylate triacrylate (TPETA) at a 1:1 ratio. This photopolymer demonstrated an improvement in biocompatibility over PMMA which is already known to be biocompatible and has been extensively used in the biomedical field. Additionally, photoembossed films showed significantly improved cell attachment and proliferation compared to their non-embossed counterparts. Surface texturing consisted of grooves of different pitches (6, 10, and 20 µm) and heights (1 µm and 2.5 µm). The 20 µm pitch photoembossed films significantly accelerated cell migration in a wound-healing assay, while films with a 6 µm pitch inhibited cells from detaching. Additionally, the relief structure obtained by photoembossing also changed the surface wettability of the substrates. Photoembossed PMMA-TPETA systems benefited from this change as it improved their water contact angle to around 70°, making it well suited for cell adhesion. PMID:27941669

Two decades of occupational (meth)acrylate patch test results and focus on isobornyl acrylate.

PubMed

Christoffers, Wietske A; Coenraads, Pieter-Jan; Schuttelaar, Marie-Louise A

2013-08-01

Acrylates constitute an important cause of occupational contact dermatitis. Isobornyl acrylate sensitization has been reported in only 2 cases. We encountered an industrial process operator with occupational contact dermatitis caused by isobornyl acrylate. (i) To investigate whether it is relevant to add isobornyl acrylate to the (meth)acrylate test series. (ii) To report patients with (meth)acrylate contact allergy at an occupational dermatology clinic. Our patch test database was screened for positive reactions to (meth)acrylates between 1993 and 2012. A selected group of 14 patients was tested with an isobornyl acrylate dilution series: 0.3%, 0.1%, 0.033%, and 0.01%. Readings were performed on D2, D3, and D7. One hundred and fifty-one patients were tested with our (meth)acrylate series; 24 had positive reactions. Most positive reactions were to 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, and diethyleneglycol diacrylate. Hypothetical screening with 2-hydroxypropyl acrylate, ethyleneglycol dimethacrylate, ethoxylated bisphenol A glycol dimethacrylate and trimethylolpropane triacrylate identified 91.7% of the 24 patients. No positive reactions were observed in 14 acrylate-positive patients tested with the isobornyl acrylate dilution series. The 0.3% isobornyl acrylate concentration induced irritant reactions in 3 patients. We report a rare case of allergic contact dermatitis caused by isobornyl acrylate. However, this study provides insufficient support for isobornyl acrylate to be added to a (meth)acrylate series. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Multidose Preservative Free Eyedrops by Selective Removal of Benzalkonium Chloride from Ocular Formulations.

PubMed

Hsu, Kuan-Hui; Gupta, Karishma; Nayaka, Harish; Donthi, Aashrit; Kaul, Siddarth; Chauhan, Anuj

2017-12-01

About 70% of eye drops contain benzalkonium chloride (BAK) to maintain sterility. BAK is an effective preservative but it can cause irritation and toxicity. We propose to mitigate ocular toxicity without compromising sterility by incorporating a filter into an eye drop bottle to selectively remove BAK during the process of drop instillation. The filter is a packed bed of particles made from poly(2-hydroxyethyl methacrylate) (pHEMA), which is a common ophthalmic material. We showed that pHEMA particle prepared by using ethoxylated trimethylolpropane triacrylate as crosslinker can be incorporated into a modified eyedrop bottle tip to selectively remove the preservative as the formulation is squeezed out of the bottle. Hydraulic permeability of the plug is measured to determine the resistance to eye drop squeezing, and % removal of BAK and drugs are determined. The modified tip has a hydraulic permeability of about 2 Darcy, which allows eyedrops formulations to flow through without excessive resistance. The tip is designed such that the patients can create an eyedrop of solution of 1-10 cP viscosity in 4 s with a nominal pressure. During this short contact time, the packed particles removed nearly 100% of benzalkonium chloride (BAK) from a 15 mL, 0.012% BAK solution but have only minimal impact on the concentration of contained active components. Our novel design can eliminate the preservative induced toxicity from eye drops thereby impacting hundreds of millions of patients with chronic ophthalmic diseases like glaucoma and dry eyes.

Analysis of the conduction mechanism and dielectric properties of N, N', N" tris(4-methylphenyl)phosphoric triamide

NASA Astrophysics Data System (ADS)

Ali, H. A. M.

2016-03-01

The structure for the powder of N,N', N"-tris(4-methylphenyl)phosphoric triamide, TMP-TA, was characterized using X-ray diffraction (XRD) and differential thermal analysis (DTA) techniques. The ac conductivity and dielectric properties were measured in the frequency range of 42-105 Hz for the bulk TMP-TA in a pellet form at different temperatures. The frequency dependence of ac conductivity was expressed by a Jonscher's universal power law. The frequency exponent (s) was determined from the fitting of experimental data of ac conductivity. The correlated barrier hopping (CBH) model was found to be responsible for the ac conduction mechanism in TMP-TA. The activation energy was calculated from the temperature dependence of ac conductivity. The values of the density of states at the Fermi level were determined for different frequencies. The components of the electric modulus (M' and M") were calculated and used to estimate the relaxation time.

Inert Reassessment Document for Trimethylolpropane - CAS No. 77-99-6

EPA Pesticide Factsheets

Trimethylolpropane is used in a large variety of commercial applications, including in the manufacturer of varnishes, resins; polyesters for polyurethane foams, textile finishes, plastictzers, and cross-linking agents for spandex fibers.

Allergic contact dermatitis due to urethane acrylate in ultraviolet cured inks.

PubMed Central

Nethercott, J R; Jakubovic, H R; Pilger, C; Smith, J W

1983-01-01

Seven workers exposed to ultraviolet printing inks developed contact dermatitis. Six cases were allergic and one irritant. A urethane acrylate resin accounted for five cases of sensitisation, one of which was also sensitive to pentaerythritol triacrylate and another also to an epoxy acrylate resin. One instance of allergy to trimethylpropane triacrylate accounted for the sixth case of contact dermatitis in this group of workers. An irritant reaction is presumed to account for the dermatitis in the individual not proved to have cutaneous allergy by patch tests. In this instance trimethylpropane triacrylate was thought to be the most likely irritating agent. Laboratory investigation proved urethane acrylate to be an allergen. The results of investigations of the sensitisation potentials of urethane acrylate, methylmethacrylate, epoxy acrylate resins, toluene-2,4-diisocyanate, and other multifunctional acrylic monomers in the albino guinea pig are presented. The interpretation of such predictive tests is discussed. Images PMID:6223656

Synthesis and characterization of branched polymers from lipase-catalyzed trimethylolpropane copolymerizations.

PubMed

Kulshrestha, Ankur S; Gao, Wei; Fu, Hongyong; Gross, Richard A

2007-06-01

Lipase-catalyzed terpolymerizations were performed with the monomers trimethylolpropane (B3), 1,8-octanediol (B2), and adipic acid (A2). Polymerizations were performed in bulk, at 70 degrees C, for 42 h, using immobilized lipase B from Candida antartica (Novozyme-435) as a catalyst. To determine the substitution pattern of trimethylolpropane (TMP) in copolymers, model compounds with variable degrees of acetylation were synthesized. Inverse-gated 13C NMR spectra were recorded to first determine the chemical shift positions for mono-, di-, and trisubstituted TMP units and, subsequently, to determine substitution of TMP units along chains. Variation of TMP in the monomer feed gave copolymers with degrees of branching (DB) from 20% to 67%. In one example, a hyperbranched copolyester with 53 mol % TMP adipate units was formed in 80% yield, with Mw 14 100 (relative to polystyrene standards), Mw/Mn 5.3, and DB 36%. Thermal and crystalline properties of the copolyesters were studied by thermogravimetric analysis and differential scanning calorimetry.

Synthetic Light-Curable Polymeric Materials Provide a Supportive Niche for Dental Pulp Stem Cells.

PubMed

Vining, Kyle H; Scherba, Jacob C; Bever, Alaina M; Alexander, Morgan R; Celiz, Adam D; Mooney, David J

2018-01-01

Dental disease annually affects billions of patients, and while regenerative dentistry aims to heal dental tissue after injury, existing polymeric restorative materials, or fillings, do not directly participate in the healing process in a bioinstructive manner. There is a need for restorative materials that can support native functions of dental pulp stem cells (DPSCs), which are capable of regenerating dentin. A polymer microarray formed from commercially available monomers to rapidly identify materials that support DPSC adhesion is used. Based on these findings, thiol-ene chemistry is employed to achieve rapid light-curing and minimize residual monomer of the lead materials. Several triacrylate bulk polymers support DPSC adhesion, proliferation, and differentiation in vitro, and exhibit stiffness and tensile strength similar to existing dental materials. Conversely, materials composed of a trimethacrylate monomer or bisphenol A glycidyl methacrylate, which is a monomer standard in dental materials, do not support stem cell adhesion and negatively impact matrix and signaling pathways. Furthermore, thiol-ene polymerized triacrylates are used as permanent filling materials at the dentin-pulp interface in direct contact with irreversibly injured pulp tissue. These novel triacrylate-based biomaterials have potential to enable novel regenerative dental therapies in the clinic by both restoring teeth and providing a supportive niche for DPSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

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

Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

PubMed

Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

2017-11-01

Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Introduction to Rocket Propulsion

DTIC Science & Technology

1991-12-01

such as epoxies, MAPO (a trifunctional aziridinyl phosphine oxide), MT-4, various isocyanates, such a TDI, HDI, IPDI, and polyols such as trimethylol...propane (2) Burning rate catalysts, such as copper chromite (or chromate), ferrocene , and several less migratory derivatives of this organic iron

Hydrogels Synthesized by Electron Beam Irradiation for Heavy Metal Adsorption

PubMed Central

Manaila, Elena; Craciun, Gabriela; Ighigeanu, Daniel; Cimpeanu, Catalina; Barna, Catalina; Fugaru, Viorel

2017-01-01

Poly(acrylamide co-acrylic acid) hydrogels were prepared by free-radical copolymerization of acrylamide and acrylic acid in aqueous solutions using electron beam irradiation in the dose range of 2.5 kGy to 6 kGy in atmospheric conditions and at room temperature. The influence of the absorbed dose, the amount of cross-linker (trimethylolpropane trimethacrylate) and initiator (potassium persulfate) on the swelling properties and the diffusion coefficient and network parameters of hydrogels were investigated. The structure and morphology of hydrogels were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The use of the obtained hydrogels by the removal of Cu2+ and Cr6+ from aqueous solutions was investigated at room temperature. During the adsorption of metal ions on hydrogels, the residual metal ion concentration in the solution was measured by an atomic absorption spectrophotometer (AAS). It has been established that the use of a relatively small amount of trimethylolpropane trimethacrylate for hydrogel preparation has led to the increasing of swelling up to 8500%. PMID:28772904

Hydrogels Synthesized by Electron Beam Irradiation for Heavy Metal Adsorption.

PubMed

Manaila, Elena; Craciun, Gabriela; Ighigeanu, Daniel; Cimpeanu, Catalina; Barna, Catalina; Fugaru, Viorel

2017-05-18

Poly(acrylamide co-acrylic acid) hydrogels were prepared by free-radical copolymerization of acrylamide and acrylic acid in aqueous solutions using electron beam irradiation in the dose range of 2.5 kGy to 6 kGy in atmospheric conditions and at room temperature. The influence of the absorbed dose, the amount of cross-linker (trimethylolpropane trimethacrylate) and initiator (potassium persulfate) on the swelling properties and the diffusion coefficient and network parameters of hydrogels were investigated. The structure and morphology of hydrogels were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The use of the obtained hydrogels by the removal of Cu 2+ and Cr 6+ from aqueous solutions was investigated at room temperature. During the adsorption of metal ions on hydrogels, the residual metal ion concentration in the solution was measured by an atomic absorption spectrophotometer (AAS). It has been established that the use of a relatively small amount of trimethylolpropane trimethacrylate for hydrogel preparation has led to the increasing of swelling up to 8500%.

Polymer impregnated bridge slabs : interim report, condition of slabs after three years of service life.

DOT National Transportation Integrated Search

1983-01-01

The condition of six concrete bridge slabs that had been in service for three years was evaluated. The top 2 in. of the four slabs that had been impregnated to a depth of about 1 in. with a methyl methacrylate and trimethylolpropane trimethacrylate m...

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hexanoic acid, 2-ethyl-, mixed... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10109 Hexanoic acid, 2-ethyl-, mixed... to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, mixed triesters with...

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hexanoic acid, 2-ethyl-, mixed... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10109 Hexanoic acid, 2-ethyl-, mixed... to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, mixed triesters with...

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Hexanoic acid, 2-ethyl-, mixed... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10109 Hexanoic acid, 2-ethyl-, mixed... to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, mixed triesters with...

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hexanoic acid, 2-ethyl-, mixed... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10109 Hexanoic acid, 2-ethyl-, mixed... to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, mixed triesters with...

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hexanoic acid, 2-ethyl-, mixed... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10109 Hexanoic acid, 2-ethyl-, mixed... to reporting. (1) The chemical substance identified as hexanoic acid, 2-ethyl-, mixed triesters with...

Preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) monolithic column by in situ polymerization and a click reaction for capillary liquid chromatography of small molecules and proteins.

PubMed

Lin, Zian; Yu, Ruifang; Hu, Wenli; Zheng, Jiangnan; Tong, Ping; Zhao, Hongzhi; Cai, Zongwei

2015-07-07

Combining free radical polymerization with click chemistry via a copper-mediated azide/alkyne cycloaddition (CuAAC) reaction in a "one-pot" process, a facile approach was developed for the preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) (AZT-co-PMA-co-PETA) monolithic column. The resulting poly(AZT-co-PMA-co-PETA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of a monolithic column. A series of alkylbenzenes, amides, anilines, and benzoic acids were used to evaluate the chromatographic properties of the polymer monolith in terms of hydrophobic, hydrophilic and cation-exchange interactions, and the results showed that the poly(AZT-co-PMA-co-PETA) monolith exhibited more flexible adjustment in chromatographic selectivity than that of the parent poly(PMA-co-PETA) and AZT-modified poly(PMA-co-PETA) monoliths. Column efficiencies for toluene, DMF, and formamide with 35,000-48,000 theoretical plates per m could be obtained at a linear velocity of 0.17 mm s(-1). The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention factors were less than 4.2%. In addition, the proposed monolith was also applied to efficient separation of sulfonamides, nucleobases and nucleosides, anesthetics and proteins for demonstrating its potential.

Synthesis, Characterization, and Visible Light Curing Capacity of Polycaprolactone Acrylate

PubMed Central

Tzeng, Jy-Jiunn; Hsiao, Yi-Ting; Wu, Yun-Ching; Chen, Hsuan; Lee, Shyh-Yuan

2018-01-01

Polycaprolactone (PCL) is drawing increasing attention in the field of medical 3D printing and tissue engineering because of its biodegradability. This study developed polycaprolactone prepolymers that can be cured using visible light. Three PCL acrylates were synthesized: polycaprolactone-530 diacrylate (PCL530DA), glycerol-3 caprolactone triacrylate (Glycerol-3CL-TA), and glycerol-6 caprolactone triacrylate (Glycerol-6CL-TA). PCL530DA has two acrylates, whereas Glycerol-3CL-TA and Glycerol-6CL-TA have three acrylates. The Fourier transform infrared and nuclear magnetic resonance spectra suggested successful synthesis of all PCL acrylates. All are liquid at room temperature and can be photopolymerized into a transparent solid after exposure to 470 nm blue LED light using 1% camphorquinone as photoinitiator and 2% dimethylaminoethyl methacrylate as coinitiator. The degree of conversion for all PCL acrylates can reach more than 80% after 1 min of curing. The compressive modulus of PCL530DA, Glycerol-3CL-TA, and Glycerol-6CL-TA is 65.7 ± 12.7, 80.9 ± 6.1, and 32.1 ± 4.1 MPa, respectively, and their compressive strength is 5.3 ± 0.29, 8.3 ± 0.18, and 3.0 ± 0.53 MPa, respectively. Thus, all PCL acrylates synthesized in this study can be photopolymerized and because of their solid structure and low viscosity, they are applicable to soft tissue engineering and medical 3D printing. PMID:29854803

Synthesis of palm oil fatty acid and trimethylolpropane based ester for biolubricant base stocks

NASA Astrophysics Data System (ADS)

Nor, Nurazira Mohd; Derawi, Darfizzi; Salimon, Jumat

2018-04-01

RBD palm oil become one of the interesting renewable resources in biolubricant application. However, palm oil cannot be used directly as lubricant due to some performance limitations such as thermal and oxidative stability. This drawback can be overcome by chemical modification through esterification with polyhydric alcohol such as trimethylolpropane (TMP). The synthesis of ester was carried out via esterification of palm oil fatty acid (POFA) with TMP in the presence of 2% sulphuric acid as catalyst at 150 °C for 5 hours. Gas Chromatography equipped with a Flame Ionization Detector (GC-FID) was used to determine the percentage composition of POTMP ester. The structure confirmation of POTMP ester was proven by Fourier Transformation Infra-Red (FTIR), proton and carbon Nuclear Magnetic Resonance (1H-NMR and 13C-NMR) spectroscopy analysis. The result showed that POTMP ester has successfully synthesized with 97.7% composition of triesters (TE), proved by GC chromatogram. Presence of ester group also evidenced by 1H NMR at 2.27-2.30 ppm and 13C NMR at 173.52-173.54 ppm. The percentage yield of POTMP ester produced was 82% and exist in liquid form at room temperature.

Pipette-tip solid-phase extraction using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a new molecularly imprinted polymer in the determination of avermectins and milbemycins in fruit juice and water samples.

PubMed

Teixeira, Roseane Andrade; Flores, Diego Hernando Ângulo; da Silva, Ricky Cássio Santos; Dutra, Flávia Viana Avelar; Borges, Keyller Bastos

2018-10-01

A simple HPLC method was developed for the determination of abamectin (ABA), eprinomectin (EPR), and moxidectin (MOX). Pipette-tip molecularly imprinted polymer solid-phase extraction (PT-MIP-SPE) using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a selective adsorbent material was studied in detail, including the washing solvent, type and volume of eluent, pH, quantity of adsorbent material and sample volume. The performance criteria for linearity, sensitivity, precision, accuracy, recovery, robustness and stability have been assessed and were within the recommended guidelines. The mean extraction recoveries/relative standard deviation for ABA 1b, EPR, ABA 1a and MOX were 98.77 ± 3.82%, 88.19 ± 2.57%, 110.54 ± 1.52% and 100.42 ± 0.59%, respectively. Finally, the results proved that PT-MIP-SPE coupled to HPLC-UV is an economical, simple and easy-to-perform technique, and presented a high potential for extraction of macrocyclic lactones in mineral water and grape and juice samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

Degradation Studies of a Trimethylolpropane Triheptanoate Lubricant Basestock

DTIC Science & Technology

1977-12-01

primary dibasic acids : azelaic , adipic, glutaric, and sebacic. From this and subsequent investigations, a dibasic acid ester evolved which has been...Rotating Cylinder Deposition Rig-Parts List 13 2 Analysis for Parent Alcohols in (1-76-5 25 3 Analysis for Parent Acids in 0-76-5 27 4 Gas...formulations: (1) dibasic acid esters formed via esterification of dibasic fatty acids and monohydric alcohols, and (2) neopentyl polyol esters of monobasic

Selective oxidation of trimethylolpropane to 2,2-bis(hydroxymethyl)butyric acid using growing cells of Corynebacterium sp. ATCC 21245.

PubMed

Sayed, Mahmoud; Dishisha, Tarek; Sayed, Waiel F; Salem, Wesam M; Temerk, Hanan A; Pyo, Sang-Hyun

2016-03-10

Multifunctional chemicals including hydroxycarboxylic acids are gaining increasing interest due to their growing applications in the polymer industry. One approach for their production is a biological selective oxidation of polyols, which is difficult to achieve by conventional chemical catalysis. In the present study, trimethylolpropane (TMP), a trihydric alcohol, was subjected to selective oxidation using growing cells of Corynebacterium sp. ATCC 21245 as a biocatalyst and yielding the dihydroxy-monocarboxylic acid, 2,2-bis(hydroxymethyl)butyric acid (BHMB). The study revealed that co-substrates are crucial for this reaction. Among the different evaluated co-substrates, a mixture of glucose, xylose and acetate at a ratio of 5:5:2 was found optimum. The optimal conditions for biotransformation were pH 8, 1v/v/m airflow and 500rpm stirring speed. In batch mode of operation, 70.6% of 5g/l TMP was converted to BHMB in 10 days. For recovery of the product the adsorption pattern of BHMB to the anion exchange resin, Ambersep(®) 900 (OH(-)), was investigated in batch and column experiments giving maximum static and dynamic binding capacities of 135 and 144mg/g resin, respectively. BHMB was separated with 89.7% of recovery yield from the fermentation broth. The approach is applicable for selective oxidation of other highly branched polyols by biotransformation. Copyright © 2016 Elsevier B.V. All rights reserved.

Final report of the safety assessment of methacrylate ester monomers used in nail enhancement products.

PubMed

2005-01-01

Methacrylate ester monomers are used in as artificial nail builders in nail enhancement products. They undergo rapid polymerization to form a hard material on the nail that is then shaped. While Ethyl Methacrylate is the primary monomer used in nail enhancement products, other methacrylate esters are also used. This safety assessment addresses 22 other methacrylate esters reported by industry to be present in small percentages as artificial nail builders in cosmetic products. They function to speed up polymerization and/or form cross-links. Only Tetrahydrofurfuryl Methacrylate was reported to the FDA to be in current use. The polymerization rates of these methacrylate esters are within the same range as Ethyl Methacrylate. While data are not available on all of these methacrylate esters, the available data demonstrated little acute oral, dermal, or i.p. toxicity. In a 28-day inhalation study on rats, Butyl Methacrylate caused upper airway irritation; the NOAEL was 1801 mg/m3. In a 28-day oral toxicity study on rats, t-Butyl Methacrylate had a NOAEL of 20 mg/kg/day. Beagle dogs dosed with 0.2 to 2.0 g/kg/day of C12 to C18 methacrylate monomers for 13 weeks exhibited effects only in the highest dose group: weight loss, emesis, diarrhea, mucoid feces, or salivation were observed. Butyl Methacrylate (0.1 M) and Isobutyl Methacrylate (0.1 M) are mildly irritating to the rabbit eye. HEMA is corrosive when instilled in the rabbit eye, while PEG-4 Dimethacrylate and Trimethylolpropane Trimethacrylate are minimally irritating to the eye. Dermal irritation caused by methacrylates is documented in guinea pigs and rabbits. In guinea pigs, HEMA, Isopropylidenediphenyl Bisglycidyl Methacrylate, Lauryl Methacrylate, and Trimethylolpropane Trimethacrylate are strong sensitizers; Butyl Methacrylate, Cyclohexyl Methacrylate, Hexyl Methacrylate, and Urethane Methacrylate are moderate sensitizers; Hydroxypropyl Methacrylate is a weak sensitizer; and PEG-4 Dimethacrylate and Triethylene Glycol Dimethacrylate are not sensitizers. Ethylene Glycol Dimethacrylate was not a sensitizer in one guinea pig study, but was a strong sensitizer in another. There is cross-reactivity between various methacrylate esters in some sensitization tests. Inhaled Butyl Methacrylate, HEMA, Hydroxypropyl Methacrylate, and Trimethylolpropane Trimethacrylate can be developmental toxicants at high exposure levels (1000 mg/kg/day). None of the methacrylate ester monomers that were tested were shown to have any endocrine disrupting activity. These methacrylate esters are mostly non-mutagenic in bacterial test systems, but weak mutagenic responses were seen in mammalian cell test systems. Chronic dermal exposure of mice to PEG-4 Dimethacrylate (25 mg, 2 x weekly for 80 weeks) or Trimethylolpropane Trimethacrylate (25 mg, 2 x weekly for 80 weeks) did not result in increased incidence of skin or visceral tumors. The carcinogenicity of Triethylene Glycol Dimethacrylate (5, 25, or 50%) was assessed in a mouse skin painting study (50 microl for 5 days/week for 78 weeks), but was not carcinogenic at any dose level tested. The Expert Panel was concerned about the strong sensitization and crossor co-reactivity potential of the methacrylate esters reviewed in this report. However, data demonstrated the rates of polymerization of these Methacrylates were similar to that of Ethyl Methacrylate and there would be little monomer available exposure to the skin. In consideration of the animal toxicity data, the CIR Expert Panel decided that these methacrylate esters should be restricted to the nail and must not be in contact with the skin. Accordingly, these methacrylate esters are safe as used in nail enhancement products when skin contact is avoided.

Analysis of Hydraulic Fluids and Lubricating Oils for the Formation of Trimethylolpropane Phosphate (TMP-P)

DTIC Science & Technology

1989-08-09

quantitative and can be ascribed to differences in experimental methodology , recovery methods and canputational procedure. one important differenc.e in...when the oil was pyrolyzed in sealed glass tubes. Aircraft turbo oil lubricants with the designation MIL-L-23699 are in canron usage throughout the...which is not explosive, not an oxidizing agent and is relatively inflamnable and non -corrosive. It has the following structure: CH2 - 0 CH3 CH2 C CH2 - 0

Modification and characterization of biodegradable methylcellulose films with trimethylolpropane trimethacrylate (TMPTMA) by γ radiation: effect of nanocrystalline cellulose.

PubMed

Sharmin, Nusrat; Khan, Ruhul A; Salmieri, Stephane; Dussault, Dominic; Bouchard, Jean; Lacroix, Monique

2012-01-18

Methylcellulose (MC)-based films were prepared by solution casting from its 1% aqueous suspension containing 0.25% glycerol. Trimethylolpropane trimethacrylate (TMPTMA) monomer (0.1-2% by wt) along with the glycerol was added to the MC suspension. The films were cast and irradiated from a radiation dose varied from 0.1 to 10 kGy. Then the mechanical properties such as tensile strength (TS), tensile modulus (TM), and elongation at break (Eb) and barrier properties of the films were evaluated. The highest TS (47.88 PMa) and TM (1791.50 MPa) of the films were found by using 0.1% monomer at 5 kGy dose. The lowest water vapor permeability (WVP) of the films was found to be 5.57 g·mm/m(2)·day·kPa (at 0.1% monomer and 5 kGy dose), which is 12.14% lower than control MC-based films. Molecular interactions due to incorporation of TMPTMA were supported by FTIR spectroscopy. A band at 1720 cm(-1) was observed due to the addition of TMPTMA in MC-based films, which indicated the typical (C═O) carbonyl stretching. For the further improvement of the mechanical and barrier properties of the film, 0.025-1% nanocrystalline cellulose (NCC) was added to the MC-based suspension containing 1% TMPTMA. Addition of NCC led to a significant improvement in the mechanical and barrier properties. The novelty of this investigation was to graft insoluble monomer using γ radiation with MC-based films and use of biodegradable NCC as the reinforcing agent.

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.

High temperature polymer concrete compositions

DOEpatents

Fontana, Jack J.; Reams, Walter

1985-01-01

This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system. A preferred formulation emphasizing the major necessary components is as follows: ______________________________________ Component A: Silica sand 60-77 wt. % Silica flour 5-10 wt. % Portland cement 15-25 wt. % Acrylamide 1-5 wt. % Component B: Styrene 50-60 wt. % Trimethylolpropane 35-40 wt. % trimethacrylate ______________________________________ and necessary initiators, accelerators, and surfactants.

Fetal and neonatal exposure to trimethylolpropane phosphate alters rat social behavior and emotional responsivity.

PubMed

Bekkedal, M Y; Rossi, J; Panksepp, J

1999-01-01

The proconvulsant compound trimethylolpropane phosphate (TMPP) was evaluated for its effects on motor, social, and emotional behaviors. Long Evans rats were treated prenatally for 13 days and/or neonatally for 10 days. Behavioral tests were performed during treatment and several days after treatment. Beginning on gestation day 9, and continuing for 13 days, 20 dams received once daily i.p. injections. Half were treated with distilled water, the other 10 received 0.2 mg TMPP/kg body weight. No external malformations were observed in the live-born offspring of TMPP- or vehicle-exposed dams. On postnatal day 3 one-half the pups were cross-fostered to dams that had the opposite treatment as their biological mothers. Also on postnatal day 3, pups were divided into two groups, one receiving injections of distilled water, the other receiving injections of 0.2 mg TMPP/kg body weight. Ten daily injections were administered i.p., beginning postnatal day 3. Motor behaviors were evaluated in step-down and paw lift tasks and no group differences were found. At 18 days of age, one half the pups were separated from the dam and their littermates. The other half of the pups continued to be housed with the dam and remaining littermates until postnatal day 50. Social interaction was measured in juvenile play and adult social investigation. Emotional responsivity was assessed in open field activity, elevated plus-maze exploration, and ultrasonic distress vocalizations. Complex interactions were found for measures of social interaction and emotional responsivity related to drug treatment, housing condition, and sex. Due to the observed sex differences. it is hypothesized that the action of TMPP may involve a change in the hormonal systems that control the differentiation of related sex-typical behaviors.

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.

High temperature concrete composites containing organosiloxane crosslinked copolymers

DOEpatents

Zeldin, A.; Carciello, N.; Kukacka, L.; Fontana, J.

High temperature polymer concrete composites comprising about 10 to 30% by weight of a liquid monomer mixture is described. It consists essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures thereof. About 70 to 90% by weight of an inert inorganic filler system containing silica sand and portland cement, Fe/sub 2/O/sub 3/, carbon black or mixtures thereof. Optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobyutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides are used to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

Effect of concentration of polyfunctional monomers on physical properties of acrylonitrile butadiene rubber under electron-beam irradiation

NASA Astrophysics Data System (ADS)

Yasin, Tariq; Ahmed, Shamshad; Ahmed, Munir; Yoshii, Fumio

2005-06-01

An investigation has been undertaken to find out the effect of concentration of different polyfunctional monomers (PFMs) on the physical properties of the acrylonitrile-butadiene rubber (NBR) crosslinked by electron beam (EB). The PFMs used were diethylene glycol dimethacrylate, trimethylol propane trimethacrylate and trimethylol propane triacrylate. The physical properties of EB-irradiated NBR sheets were evaluated by measuring the tensile strength, elongation percent at break, hardness and gel fraction. The results showed a remarkable increase in tensile strength, hardness and gel fraction as the concentration of PFMs was increased from 1 part per hundred (phr) to 5 phr in the NBR samples whereas elongation percent decreased in a steady manner. The improvement in physical properties of radiation crosslinked NBR in the presence of PFMs may be attributed to its increased crosslinking density as observed by the corresponding increase in gel content.

Viscous Flow Behaviour of Karanja Oil Based Bio-lubricant Base Oil.

PubMed

Sharma, Umesh Chandra; Sachan, Sadhana; Trivedi, Rakesh Kumar

2018-01-01

Karanja oil (KO) is widely used for synthesis of bio-fuel karanja oil methyl ester (KOME) due to its competitive price, good energy values and environmentally friendly combustion properties. Bio-lubricant is another value added product that can be synthesized from KO via chemical modification. In this work karanja oil trimethylolpropane ester (KOTMPE) bio-lubricant was synthesized and evaluated for its viscous flow behaviour. A comparison of viscous flow behaviours of natural KO and synthesized bio-fuel KOME and bio-lubricant KOTMPE was also made. The aim of this comparison was to validate the superiority of KOTMPE bio-lubricant over its precursors KO and KOME in terms of stable viscous flow at high temperature and high shear rate conditions usually encountered in engine operations and industrial processes. The free fatty acid (FFA) content of KO was 5.76%. KOME was synthesized from KO in a two-step, acid catalyzed esterification followed by base catalyzed transesterification, process at 65°C for 5 hours with oil-methanol ratio 1:6, catalysts H 2 SO 4 and KOH (1 and 1.25% w/w KO, respectively). In the final step, KOTMPE was prepared from KOME via transesterification with trimethylolpropane (TMP) at 150°C for 3 hours with KOME-TMP ratio 4:1 and H 2 SO 4 (2% w/w KOME) as catalyst. The viscosity versus temperature studies were made at 0-80°C temperatures in shear rate ranges of 10-1000 s -1 using a Discovery Hybrid Rheometer, model HR-3 (TA instruments, USA). The study found that viscosities of all three samples decreased with increase in temperature, though KOTMPE was able to maintain a good enough viscosity at elevated temperatures due to chemical modifications in its molecular structure. The viscosity index (VI) value for KOTMPE was 206.72. The study confirmed that the synthesized bio-lubricant KOTMPE can be used at high temperatures as a good lubricant, though some additives may be required to improve properties other than viscosity.

Determination of the thermal stability of fluids by tensimetry - Instrumentation and procedure

NASA Technical Reports Server (NTRS)

Helmick, Larry S.; Jones, William R., Jr.

1990-01-01

A computerized tensimeter and experimental procedure for determination of the thermal decomposition temperature (T sub d) of perfluoro alkylethers were developed and tested. Both the apparatus and the procedure are described in detail. Results of testing with bis(2-ethylhexyl) phthalate and trimethylolpropane triheptanoate demonstrate that the reciprocal of the decomposition temperature is a linear function of the logarithm of the gas volume/heated liquid volume ratio. The T sub d obtained for each compound at a gas volume/heated liquid volume ration of one was similar to the value previously reported using an isoteniscope technique. Results of testing with a polymer of hexafluoropropylene oxide demonstrate that this instrument and procedure can be used to determine the T sub d of perfluoro alkylethers.

Determination of the thermal stability of perfluoroalkylethers by tensimetry: Instrumentation and Procedure

NASA Technical Reports Server (NTRS)

Helmick, Larry S.; Jones, William R., Jr.

1989-01-01

A computerized tensimeter and experimental procedure for determination of the thermal decomposition temperature (T sub d) of perfluoro alkylethers were developed and tested. Both the apparatus and the procedure are described in detail. Results of testing with bis(2-ethylhexyl) phthalate and trimethylolpropane triheptanoate demonstrate that the reciprocal of the decomposition temperature is a linear function of the logarithm of the gas volume/heated liquid volume ratio. The T sub d obtained for each compound at a gas volume/heated liquid volume ration of one was similar to the value previously reported using an isoteniscope technique. Results of testing with a polymer of hexafluoropropylene oxide demonstrate that this instrument and procedure can be used to determine the T sub d of perfluoroalkylethers.

High temperature concrete composites containing organosiloxane crosslinked copolymers

DOEpatents

Zeldin, Arkady; Carciello, Neal; Kukacka, Lawrence; Fontana, Jack

1980-01-01

This invention relates to high temperature polymer concrete composites comprising about 10-30% by weight of a liquid monomer mixture consisting essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures theroef; and about 70-90% by weight of an inert inorganic filler system containing silica sand and preferably a member selected from the group consisting of portland cement, Fe.sub.2 O.sub.3, carbon black and mixtures thereof; and optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

High temperature chemically resistant polymer concrete

DOEpatents

Sugama, T.; Kukacka, L.E.

High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

Macroradical initiated polymerisation of acrylic and methacrylic monomers.

PubMed

Mijangos, Irene; Guerreiro, António; Piletska, Elena; Whitcombe, Michael J; Karim, Kal; Chianella, Iva; Piletsky, Sergey

2009-10-01

An approach has been developed for the grafting of monomers onto poly(trimethylolpropane trimethacrylate) (polyTRIM) particles using 2,2-diethyl dithiocarbamic acid benzyl ester (DDCABE) as an initiator. A set of polymers was prepared with this technique over different lengths of time and the kinetics of the reaction studied experimentally. It was found that the grafting of initiator to the polymeric support followed a second order reaction, while the subsequent addition of monomers from solution into the polyTRIM macroradicals followed a first order reaction. The living nature of the iniferter modified macroradicals permits easy consecutive grafting of multiple polymeric layers, allowing straightforward functionalisation of particles. However, the effectiveness of the grafted initiator decreased with each cycle of polymerisation. This technique can be used for a wide range of applications in analytical and biochemistry.

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.

Radiation-induced polymerization for the immobilization of penicillin acylase

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

Boccu, E.; Carenza, M.; Lora, S.

The immobilization of Escherichia coli penicillin acylase was investigated by radiation-induced polymerization of 2-hydroxyethyl methacrylate at low temperature. A leak-proof composite that does not swell in water was obtained by adding the cross-linking agent trimethylolpropane trimethacrylate to the monomer-aqueous enzyme mixture. Penicillin acylase, which was immobilized with greater than 70% yield, possessed a higher Km value toward the substrate 6-nitro-3-phenylacetamidobenzoic acid than the free enzyme form (Km = 1.7 X 10(-5) and 1 X 10(-5) M, respectively). The structural stability of immobilized penicillin acylase, as assessed by heat, guanidinium chloride, and pH denaturation profiles, was very similar to that ofmore » the free-enzyme form, thus suggesting that penicillin acylase was entrapped in its native state into aqueous free spaces of the polymer matrix.« less

Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

NASA Astrophysics Data System (ADS)

Kan, Xianwen; Geng, Zhirong; Zhao, Yao; Wang, Zhilin; Zhu, Jun-Jie

2009-04-01

Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe3O4 nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

Computer-aided method for the determination of Hansen solubility parameters. Application to the miscibility of refrigerating lubricant and new refrigerant

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

Remigy, J.C.; Nakache, E.; Brechot, P.D.

This article presents a method which allows one to find the Hansen solubility parameters by means of data processing. In the first part, the authors present the thermodynamical principle of Hansen parameters, and then they explain the model used to find parameters from experimental data. They validate the method by studying the solubility parameters of CFC-12 (dichlorodifluoromethane), HFC-134a (1,1,1,2-tetrafluoroethane), neopentylglycol esters, trimethylolpropane esters, dipentaerythritol esters, and pentaerythritol esters. Then, the variation of Hansen parameters are studied as well as the relation between the miscibility temperature (the temperature at which a blend passes from the miscible state to the immiscible state)more » and the interaction distance. The authors establish the critical interaction distance of HFC-134a which determines the solubility limit and they study its variation with temperature.« less

Experimental mixture design as a tool for the synthesis of antimicrobial selective molecularly imprinted monodisperse microbeads.

PubMed

Benito-Peña, Elena; Navarro-Villoslada, Fernando; Carrasco, Sergio; Jockusch, Steffen; Ottaviani, M Francesca; Moreno-Bondi, Maria C

2015-05-27

The effect of the cross-linker on the shape and size of molecular imprinted polymer (MIP) beads prepared by precipitation polymerization has been evaluated using a chemometric approach. Molecularly imprinted microspheres for the selective recognition of fluoroquinolone antimicrobials were prepared in a one-step precipitation polymerization procedure using enrofloxacin (ENR) as the template molecule, methacrylic acid as functional monomer, 2-hydroxyethyl methacrylate as hydrophilic comonomer, and acetonitrile as the porogen. The type and amount of cross-linker, namely ethylene glycol dimethacrylate, divinylbenzene or trimethylolpropane trimethacrylate, to obtain monodispersed MIP spherical beads in the micrometer range was optimized using a simplex lattice design. Particle size and morphology were assessed by scanning electron microscopy, dynamic light scattering, and nitrogen adsorption measurements. Electron paramagnetic resonance spectroscopy in conjunction with a nitroxide as spin probe revealed information about the microviscosity and polarity of the binding sites in imprinted and nonimprinted polymer beads.

Endoplasmic reticulum-Golgi intermediate compartment protein 3 knockdown suppresses lung cancer through endoplasmic reticulum stress-induced autophagy.

PubMed

Hong, Seong-Ho; Chang, Seung-Hee; Cho, Kyung-Cho; Kim, Sanghwa; Park, Sungjin; Lee, Ah Young; Jiang, Hu-Lin; Kim, Hyeon-Jeong; Lee, Somin; Yu, Kyeong-Nam; Seo, Hwi Won; Chae, Chanhee; Kim, Kwang Pyo; Park, Jongsun; Cho, Myung-Haing

2016-10-04

Trafficking from the endoplasmic reticulum (ER) to the Golgi apparatus is elevated in cancer cells. Therefore, proteins of the ER-Golgi intermediate compartment (ERGIC) attract significant attention as targets for cancer treatment. Enhanced cancer cell growth and epithelial-mesenchymal transition by ERGICs correlates with poor-prognosis of lung cancer. This prompted us to assess whether knockdown of ERGIC3 may decrease lung cancer growth. To test the hypothesis, the effects of ERGIC3 short hairpin RNA (shERGIC3) on ER stress-induced cell death and lung tumorigenesis were investigated both in vitro and in vivo. Knockdown of ERGIC3 led to ER stress-induced autophagic cell death and suppression of proliferation in the A549 human lung cancer cell-line. Moreover, non-invasive aerosol-delivery of shERGIC3 using the biocompatible carrier glycerol propoxylate triacrylate and spermine (GPT-SPE) inhibited lung tumorigenesis in the K-rasLA1 murine model of lung cancer. Our data suggest that suppression of ERGIC3 could provide a framework for the development of effective lung cancer therapies.

The effect of phase change materials on the frontal polymerization of a triacrylate

NASA Astrophysics Data System (ADS)

Viner, Veronika G.; Pojman, John A.; Golovaty, Dmitry

2010-06-01

The production of smoke and fumes is a major obstacle to the practical use of thermal frontal polymerization. The front temperature and the amount of smoking can be reduced by adding inert fillers, such as clay and silica, to the reactive mixture. Here we investigate the possibility of incorporating inert materials that melt (so-called phase change materials) to the mixture. By performing both experiments and mathematical modeling, we demonstrate that, in addition to the standard parameters of frontal polymerization, the front temperature and velocity depend on the melting point and heat of fusion of the phase change material. We use the method of matched asymptotic expansions to develop an explicit expression for the velocity of the reaction front. The expression demonstrates that the behavior of the front is determined by the difference between the reaction temperature and the melting temperature, with the front being slower and cooler if melting occurs farther ahead of the reaction front. The theoretical trends are hard to confirm directly because different characteristics of the phase change material cannot be varied separately.

Synthesis of TMP-ester biolubricant basestock from palm stearin fatty acids

NASA Astrophysics Data System (ADS)

Fadzel, Fatimatuzzahraa Mohd; Salimon, Jumat; Derawi, Darfizzi

2018-04-01

A potential biolubricant; TMP-ester was produced via esterification of fatty acids (FA) from palm stearin (PS) with trimethylolpropane (TMP). The synthesis was conducted at four conditions; temperature, time, molar ratio of FA:TMP and H2SO4 as catalyst (by percent based on the weight of FA and TMP) that are 150 °C, 2 hours, 4:1 and 1% of H2SO4 respectively. The composition of ester produced was determined using gas chromatography (GC-FID). The presence of ester group was confirmed by the means of FTIR by the existence of strong carboxyl band of ester, v(C=O) at 1746cm-1 and 1H and 13C NMR spectroscopy shows the chemical shift, δ of ester, C=O at 2.27-2.31 ppm and 173.45 ppm accordingly. From the esterification reaction, 95% product of TMP-ester was formed. The thermal and oxidative stability of TMP-ester is 200°C.

Preparation and properties of high storage stability polyester polyol dispersion for two-component waterborne polyurethane coating

NASA Astrophysics Data System (ADS)

Hao, H.; Hu, J. Q.; Wang, F.; Tu, W. P.

2017-01-01

A new type of polyester polyol dispersion with good storage stability was prepared based on a hydrophilic monomer 5-sodium sulfodimethyl isophthalate (5-SIPM), and frequently-used monomers such as neopentyl glycol (NPG), dimethyl terephthalate (DMT), dimethyl phthalate (DMP) and trimethylolpropane (TMP) by the transpolycondensation and polycondensation method. The polyester polyol dispersion was characterized by FTIR and GPC. The proper content of these monomers were determined by the performance of polyester dispersion: the content of TMP was 15wt%, the content of NPG was 7.5wt% and the hydrophilic monomer 5-SIPM content was 5wt%. Two-component waterborne polyurethane (2K-WPU) coatings were prepared by Bayhydur® XP2487/1 and polyester polyol dispersions, which were stored before and after at 40 ° for 6 weeks, the prepared films have no differences in drying time, adhesion, pencil hardness, gloss and chemical resistance, the result also reveals that the polyester polyol dispersion have excellent storage stability resistance.

Polymer concrete composites for the production of high strength pipe and linings in high temperature corrosive environments

DOEpatents

Zeldin, A.; Carciello, N.; Fontana, J.; Kukacka, L.

High temperature corrosive resistant, non-aqueous polymer concrete composites are described. They comprise about 12 to 20% by weight of a water-insoluble polymer binder polymerized in situ from a liquid monomer mixture consisting essentially of about 40 to 70% by weight of styrene, about 25 to 45% by weight acrylonitrile and about 2.5 to 7.5% by weight acrylamide or methacrylamide and about 1 to 10% by weight of a crosslinking agent. This agent is selected from the group consisting of trimethylolpropane trimethacrylate and divinyl benzene; and about 80 to 88% by weight of an inert inorganic filler system containing silica sand and portland cement, and optionally Fe/sub 2/O/sub 3/ or carbon black or mica. A free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other organic peroxides and combinations thereof to initiate crosspolymerization of the monomer mixture in the presence of said inorganic filler.

Non-biodegradable polymer particles for drug delivery: A new technology for "bio-active" restorative materials.

PubMed

Imazato, Satoshi; Kitagawa, Haruaki; Tsuboi, Ririko; Kitagawa, Ranna; Thongthai, Pasiree; Sasaki, Jun-Ichi

2017-09-26

To develop dental restorative materials with "bio-active" functions, addition of the capability to release active agents is an effective approach. However, such functionality needs to be attained without compromising the basic properties of the restorative materials. We have developed novel non-biodegradable polymer particles for drug delivery, aimed for application in dental resins. The particles are made using 2-hydroxyethyl methacrylate (HEMA) and a cross-linking monomer trimethylolpropane trimethacrylate (TMPT), with a hydrophilic nature to adsorb proteins or water-soluble antimicrobials. The polyHEMA/TMPT particles work as a reservoir to release fibroblast growth factor-2 (FGF-2) or cetylpyridinium chloride (CPC) in an effective manner. Application of the polyHEMA/TMPT particles loaded with FGF-2 to adhesives, or those loaded with CPC to resin-based endodontic sealers or denture bases/crowns is a promising approach to increase the success of the treatments by conferring "bio-active" properties to these materials to induce tissue regeneration or to inhibit bacterial infection.

Occupational methacrylate and acrylate allergy--cross-reactions and possible screening allergens.

PubMed

Aalto-Korte, Kristiina; Henriks-Eckerman, Maj-Len; Kuuliala, Outi; Jolanki, Riitta

2010-12-01

Acrylic resin monomers, especially acrylates and methacrylates, are important occupational allergens. To analyse patterns of concomitant patch test reactions to acrylic monomers in relation to exposure, and to suggest possible screening allergens. We reviewed the patch test files for the years 1994-2009 at the Finnish Institute of Occupational Health for allergic reactions to acrylic monomers, and analysed the clinical records of sensitized patients. In a group of 66 patients allergic to an acrylic monomer, the most commonly positive allergens were three methacrylates, namely ethyleneglycol dimethacrylate (EGDMA), 2-hydroxyethyl methacrylate (2-HEMA) and 2-hydroxypropyl methacrylate (2-HPMA), and an acrylate, namely diethyleneglycol diacrylate (DEGDA). The patterns of concomitant reactions imply that exposure to methacrylates may induce cross-reactivity to acrylates, whereas exposure to acrylates usually does not lead to cross-allergy to methacrylates. Screening for triethyleneglycol diacrylate (TREGDA) in the baseline series was found to be useful, as 3 of 8 patients with diagnosed occupational acrylate allergy might have been missed without the screening. A short screening series of four allergens, EGDMA, DEGDA, 2-HPMA and pentaerythritol triacrylate (PETA), would have screened 93% of our 66 patients; each of the remaining 5 patients reacted to different acrylic monomer(s). © 2010 John Wiley & Sons A/S.

New Elastomeric Materials Based on Natural Rubber Obtained by Electron Beam Irradiation for Food and Pharmaceutical Use

PubMed Central

Craciun, Gabriela; Manaila, Elena; Stelescu, Maria Daniela

2016-01-01

The efficiency of polyfunctional monomers as cross-linking co-agents on the chemical properties of natural rubber vulcanized by electron beam irradiation was studied. The following polyfunctional monomers were used: trimethylolpropane-trimethacrylate, zinc-diacrylate, ethylene glycol dimethacrylate, triallylcyanurate and triallylisocyanurate. The electron beam treatment was done using irradiation doses in the range of 75 kGy–300 kGy. The gel fraction, crosslink density and effects of different aqueous solutions, by absorption tests, have been investigated as a function of polyfunctional monomers type and absorbed dose. The samples gel fraction and crosslink density were determined on the basis of equilibrium solvent-swelling measurements by applying the modified Flory–Rehner equation for tetra functional networks. The absorption tests were done in accordance with the SR ISI 1817:2015 using distilled water, acetic acid (10%), sodium hydroxide (1%), ethylic alcohol (96%), physiological serum (sodium chloride 0.9%) and glucose (glucose monohydrate 10%). The samples structure and morphology were investigated by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy techniques. PMID:28774150

Preparation of thermo-responsive membranes. II.

PubMed

Nozawa, I; Suzuki, Y; Sato, S; Sugibayashi, K; Morimoto, Y

1991-05-01

Two types of liquid crystal (LC)-immobilized membranes were prepared by a soaking method and sandwich method to control the permeation of indomethacin, as a model drug, in response to local and systemic fever. Monooxyethylene trimethylolpropane tristearate (MTTS) was used as a model LC because it has a gel-liquid crystal phase transition temperature near the body temperature, 39-40 degrees C in phosphate buffered saline (pH 7.4). Two porous polypropylene (PP) membranes were soaked into 20% MTTS chloroform solution in the soaking method, and two PP membranes were poured with the melted MTTS and pressed in the sandwich method. Thermo-response efficacy of the soaked membrane was dependent upon the content of MTTS in MTTS membrane, and the MTTS content above the void volume of PP membrane (38%) was needed for high efficacy. On the other hand, the sandwich membrane exhibited higher thermo-response efficacy than the soaked membrane, because more LC was embedded in the pores of sandwich membrane than that of the soaked membrane. The sandwich membrane permeation of indomethacin was sharply controlled by temperature changes between 32 and 38 degrees C.

New Elastomeric Materials Based on Natural Rubber Obtained by Electron Beam Irradiation for Food and Pharmaceutical Use.

PubMed

Craciun, Gabriela; Manaila, Elena; Stelescu, Maria Daniela

2016-12-21

The efficiency of polyfunctional monomers as cross-linking co-agents on the chemical properties of natural rubber vulcanized by electron beam irradiation was studied. The following polyfunctional monomers were used: trimethylolpropane-trimethacrylate, zinc-diacrylate, ethylene glycol dimethacrylate, triallylcyanurate and triallylisocyanurate. The electron beam treatment was done using irradiation doses in the range of 75 kGy-300 kGy. The gel fraction, crosslink density and effects of different aqueous solutions, by absorption tests, have been investigated as a function of polyfunctional monomers type and absorbed dose. The samples gel fraction and crosslink density were determined on the basis of equilibrium solvent-swelling measurements by applying the modified Flory-Rehner equation for tetra functional networks. The absorption tests were done in accordance with the SR ISI 1817:2015 using distilled water, acetic acid (10%), sodium hydroxide (1%), ethylic alcohol (96%), physiological serum (sodium chloride 0.9%) and glucose (glucose monohydrate 10%). The samples structure and morphology were investigated by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy techniques.

Development and evaluation of spherical molecularly imprinted polymer beads.

PubMed

Kempe, Henrik; Kempe, Maria

2006-06-01

The majority of studies on molecularly imprinted polymers has until now been carried out on irregularly shaped particles prepared by grinding of polymer monoliths. The preparation procedures are time- and labor-consuming and produce particles of wide size distributions. To answer the need for fast and straightforward routes to spherical molecularly imprinted polymer beads, we have developed a method comprising the formation of droplets of pre-polymerization solution directly in mineral oil by vigorous mixing followed by transformation of the droplets into solid spherical beads by photoinduced free-radical polymerization. No detergents or stabilizers were required for the droplet formation. Factors influencing the bead synthesis have been investigated and are detailed here. The beads were evaluated in parallel with corresponding irregularly shaped particles prepared from polymer monoliths. Conditions for the synthesis of propranolol-imprinted poly(methacrylic acid-co-trimethylolpropane trimethacrylate) beads in the size range of 1-100 microm in almost quantitative yield are described. The beads were applied as the recognition element in a 96-well plate format radioligand assay of propranolol in human serum.

A Novel Methodology for the Synthesis of Acyloxy Castor Polyol Esters: Low Pour Point Lubricant Base Stocks.

PubMed

Kamalakar, Kotte; Mahesh, Goli; Prasad, Rachapudi B N; Karuna, Mallampalli S L

2015-01-01

Castor oil, a non-edible oil containing hydroxyl fatty acid, ricinoleic acid (89.3 %) was chemically modified employing a two step procedure. The first step involved acylation (C(2)-C(6) alkanoic anhydrides) of -OH functionality employing a green catalyst, Kieselguhr-G and solvent free medium. The catalyst after reaction was filtered and reused several times without loss in activity. The second step is esterification of acylated castor fatty acids with branched mono alcohol, 2-ethylhexanol and polyols namely neopentyl glycol (NPG), trimethylolpropane (TMP) and pentaerythritol (PE) to obtain 16 novel base stocks. The base stocks when evaluated for different lubricant properties have shown very low pour points (-30 to -45°C) and broad viscosity ranges 20.27 cSt to 370.73 cSt, higher viscosity indices (144-171), good thermal and oxidative stabilities, and high weld load capacities suitable for multi-range industrial applications such as hydraulic fluids, metal working fluids, gear oil, forging and aviation applications. The study revealed that acylated branched mono- and polyol esters rich in monounsaturation is desirable for developing low pour point base stocks.

Structural and Interfacial Properties of Hyperbranched-Linear Polymer Surfactant.

PubMed

Qiang, Taotao; Bu, Qiaoqiao; Huang, Zhaofeng; Wang, Xuechuan

2014-01-01

With oleic acid grafting modification, a series of hyperbranched-linear polymer surfactants (HLPS) were prepared by hydroxyl-terminated hyperbranched polymer (HBP), which was gained through a step synthesis method using trimethylolpropane and AB 2 monomer. The AB 2 monomers were obtained through the Michael addition reaction of methyl acrylate and diethanol amine. The structures of HLPS were characterised by Fourier transform infrared spectrophotometer and nuclear magnetic resonance (NMR), which indicated that HBP was successfully modified by oleic acid. Furthermore, the properties of surface tension and critical micelle concentration of HLPS solution showed that HLPS can significantly reduce the surface tension of water. The morphology of the HLPS solution was characterised by dynamic light scattering, which revealed that HLPS exhibited a nonmonotonic appearance in particle size at different scattering angles owing to the different replaced linear portions. The relationships of the surface pressure to monolayer area and time were measured using the Langmuir-Blodgett instrument, which showed that the surface tension of monolayer molecules increased with the increasing of hydrophobic groups. In addition, the interface conditions of different replaced HLPS solutions were simulated.

Development of molecularly imprinted polymer in porous film format for binding of phenol and alkylphenols from water.

PubMed

Gryshchenko, Andriy O; Bottaro, Christina S

2014-01-20

Molecularly imprinted polymers (MIPs) were fabricated on glass slides with a "sandwich" technique giving ~20 µm thick films. Methanol/water as a solvent, and polyethyleneglycol and polyvinylacetate as solvent modifiers, were used to give a porous morphology, which was studied with scanning electron microscopy and gravimetric analysis. Various MIPs were synthesized through non-covalent imprinting with phenol as the template; itaconic acid, 4-vinylpyridine, and styrene as monomers; ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and pentaerythritol triacrylate (PETA) as cross-linkers. Binding and imprinting properties of the MIPs were evaluated based on phenol adsorption isotherms. Since phenol has only one weakly acidic hydroxyl group and lacks unique structural characteristics necessary for binding specificity, the preparation of selective MIPs was challenging. The recognition of phenol via hydrogen bonding is suppressed in water, while hydrophobic interactions, though promoted, are not specific enough for highly-selective phenol recognition. Nevertheless, the styrene-PETA MIP gave modest imprinting effects, which were higher at lower concentrations (Imprinting Factor (IF) = 1.16 at 0.5 mg·L(-1)). The isotherm was of a Freundlich type over 0.1-40 mg·L(-1) and there was broad cross-reactivity towards other structurally similar phenols. This shows that phenol MIPs or simple adsorbents can be developed based on styrene for hydrophobic binding, and PETA to form a tighter, hydrophilic network.

Optimization of esterification of oleic acid and trimethylolpropane (TMP) and pentaerythritol (PE)

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

Mahmud, Hamizah Ammarah; Salimon, Jumat

Vegetable oil (VO) is the most potential alternative to replace mineral oil for lubricant due to better lubricating properties and great physicochemical properties. Chemical modification has to be done to overcome low temperature performance and low oxidation instability due to the presence of β-hydrogen atoms of glycerol molecule. The optimization of esterification of oleic acid and polyhydric alcohol with sulfuric acid catalyst was carried out to find the optimum conditions with the highest yield. Reeaction variables such as; molar ratio, temperature, duration and catalyst concentration. Two types of polyhydric alcohol have been used; TMP and PE. The optimum results showedmore » oleic acid successfully converted 91.2% ester TMP and 92.7% ester PE at duration: 5 hours (Ester TMP), 6 hours (Ester PE); temperature: 150°C (ester TMP), 180°C (Ester PE); catalyst concentration: 1.5% (w/w); and mol ratio: 3.9:1 (ester TMP), 4.9:1 (ester PE). From the data obtained, mole ratio showed most influenced factors to the increasing yields of ester conversions.. The TMP/PE ester was confirmed using gas chromatography (GC-FID), Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR)« less

Vapor-liquid interfacial reaction to fabricate superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabric for oil/water separation

NASA Astrophysics Data System (ADS)

Li, Hongqiang; Liang, Tao; Lai, Xuejun; Su, Xiaojing; Zhang, Lin; Zeng, Xingrong

2018-01-01

With oil spill accidents and oil industrial wastewater increasing, oil/water separation has attracted much attention in recent years. Herein, we report the fabrication of superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabrics for oil/water separation via vapor-liquid interfacial reaction. It is based on sol-gel reaction of tetraethyl orthosilicate (TEOS) to generate silica and thiol-ene reaction between poly(ethylene glycol) dimethacrylate (PEGDMA) and trimethylolpropane tris(3-mercaptopropionate) (TTMP) to form crosslinked hydrophilic polymer on polyester fabric under the catalysis of butylamine/ammonia vapor. The chemical structure of the surfaces on thiol-ene/silica hybrid decorated fabric was confirmed by FTIR and XPS, and obvious micro-nano morphology and roughness were observed with SEM and AFM. The water contact angle of the fabric attained 0° in 0.36 s, and the underwater oil contact angle reached up to 160°. Importantly, the fabric exhibited high separation efficiency at 99.5%, fast water flux above 71600 Lm-2h-1 and excellent recyclability in oil/water separation. Our findings open a new strategy to fabricate organic-inorganic hybrid superhydrophobic and underwater superoleophobic materials for oil/water separation.

UV-Induced [2+2] Grafting-To Reactions for Polymer Modification of Cellulose.

PubMed

Conradi, Matthias; Ramakers, Gijs; Junkers, Thomas

2016-01-01

Benzaldehyde-functional cellulose paper sheets have been synthesized via tosylation of cellulose (Whatman No 5) followed by addition of p-hydroxy benzaldehyde. Via UV-induced Paterno-Büchi [2+2] cycloaddition reactions, these aldehyde functional surfaces are grafted with triallylcyanurate, trimethylolpropane allyl ether, and vinyl chloroacetate. In the following, allyl-functional polymers (poly(butyl acrylate), pBA, Mn = 6990 g mol(-1) , Đ = 1.12 and poly(N-isopropyl acrylamide), pNIPAAm, Mn = 9500 g mol(-1) , Đ = 1.16) synthesized via reversible addition fragmentation chain transfer polymerization are conjugated to the celloluse surface in a UV-induced grafting-to approach. With pBA, hydrophobic cellulose sheets are obtained (water contact angle 116°), while grafting of pNIPAAm allows for generation of "smart" surfaces, which are hydrophilic at room temperature, but that become hydrophobic when heated above the characteristic lower critical solution temperature (93° contact angle). The Paterno-Büchi reaction has been shown to be a versatile synthetic tool that also performs well in grafting-to approaches whereby its overall performance seems to be close to that of radical thiol-ene reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solution-Processed Wide-Bandgap Organic Semiconductor Nanostructures Arrays for Nonvolatile Organic Field-Effect Transistor Memory.

PubMed

Li, Wen; Guo, Fengning; Ling, Haifeng; Liu, Hui; Yi, Mingdong; Zhang, Peng; Wang, Wenjun; Xie, Linghai; Huang, Wei

2018-01-01

In this paper, the development of organic field-effect transistor (OFET) memory device based on isolated and ordered nanostructures (NSs) arrays of wide-bandgap (WBG) small-molecule organic semiconductor material [2-(9-(4-(octyloxy)phenyl)-9H-fluoren-2-yl)thiophene]3 (WG 3 ) is reported. The WG 3 NSs are prepared from phase separation by spin-coating blend solutions of WG 3 /trimethylolpropane (TMP), and then introduced as charge storage elements for nonvolatile OFET memory devices. Compared to the OFET memory device with smooth WG 3 film, the device based on WG 3 NSs arrays exhibits significant improvements in memory performance including larger memory window (≈45 V), faster switching speed (≈1 s), stable retention capability (>10 4 s), and reliable switching properties. A quantitative study of the WG 3 NSs morphology reveals that enhanced memory performance is attributed to the improved charge trapping/charge-exciton annihilation efficiency induced by increased contact area between the WG 3 NSs and pentacene layer. This versatile solution-processing approach to preparing WG 3 NSs arrays as charge trapping sites allows for fabrication of high-performance nonvolatile OFET memory devices, which could be applicable to a wide range of WBG organic semiconductor materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polymer monolithic capillary microextraction combined on-line with inductively coupled plasma MS for the determination of trace rare earth elements in biological samples.

PubMed

Zhang, Lin; Chen, Beibei; He, Man; Hu, Bin

2013-07-01

A rapid and sensitive method based on polymer monolithic capillary microextraction combined on-line with microconcentric nebulization inductively coupled plasma MS has been developed for the determination of trace/ultratrace rare earth elements in biological samples. For this purpose, the iminodiacetic acid modified poly(glycidyl methacrylate-trimethylolpropane trimethacrylate) monolithic capillary was prepared and characterized by SEM and FTIR spectroscopy. Factors affecting the extraction efficiency, such as sample pH, sample flow rate, sample/eluent volume, and coexisting ions were investigated in detail. Under the optimal conditions, the LODs for rare earth elements were in the range of 0.08 (Er) to 0.97 ng/L (Nd) with a sampling frequency of 8.5 h(-1), and the RSDs were between 1.5% (Sm) and 7.4% (Nd) (c = 20 ng/L, n = 7). The proposed method was successfully applied to the analysis of trace/ultratrace rare earth elements in human urine and serum samples, and the recoveries for the spiked samples were in the range of 82-105%. The developed method was simple, rapid, sensitive, and favorable for the analysis of trace/ultratrace rare earth elements in biological samples with limited sample volume. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selective solid-phase extraction based on molecularly imprinted technology for the simultaneous determination of 20 triazole pesticides in cucumber samples using high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Zhao, Fengnian; She, Yongxin; Zhang, Chao; Cao, Xiaolin; Wang, Shanshan; Zheng, Lufei; Jin, Maojun; Shao, Hua; Jin, Fen; Wang, Jing

2017-10-01

A selective analytical method for the simultaneous determination of 20 triazole fungicides and plant growth regulators in cucumber samples was developed using solid-phase extraction with specific molecularly imprinted polymers (MIPs) as adsorbents. The MIPs were successfully prepared by precipitation polymerization using triadimefon as the template molecule, methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the crosslinker, and acetonitrile as the porogen. The performance and recognition mechanism for both the MIPs and non-molecularly imprinted polymers were evaluated using adsorption isotherms and adsorption kinetics. Liquid chromatography-tandem quadrupole mass spectrometry was used to identify and quantify the target analytes. The solid-phase extraction using the MIPs was rapid, convenient, and efficient for extraction and enrichment of the 20 triazole pesticides from cucumber samples. The recoveries obtained at three concentration levels (1, 2, and 10μgL -1 ) ranged from 82.3% to 117.6% with relative standard deviations of less than 11.8% (n=5) for all analytes. The limits of detection for the 20 triazole pesticides were all less than 0.4μgL -1 , and were sufficient to meet international standards. Copyright © 2017 Elsevier B.V. All rights reserved.

Application of stored waveform ion modulation 2D-FTICR MS/MS to the analysis of complex mixtures.

PubMed

Ross, Charles W; Simonsick, William J; Aaserud, David J

2002-09-15

Component identification of complex mixtures, whether they are from polymeric formulations or combinatorial synthesis, by conventional MS/MS techniques generally requires component separation by chromatography or mass spectrometry. An automated means of acquiring simultaneous MS/MS data from a complex mixture without prior separation is obtained from stored waveform ion modulation (SWIM) two-dimensional FTICR MS/MS. The technique applies a series of SWIFT excitation waveforms whose frequency domain magnitude spectrum is a sinusoid increasing in frequency from one waveform to the next. The controlled dissociation of the precursor ions produces an associated modulation of the product ion abundances. Fourier transformation of these abundances reveals the encoded modulation frequency from which connectivities of precursor and product ions are observed. The final result is total assignment of product ions for each precursor ion in a mixture from one automated experiment. We demonstrated the applicability of SWIM 2D-FTICR MS/MS to two diverse samples of industrial importance. We characterized structured polyester oligomers and products derived from combinatorial synthesis. Fragmentation pathways identified in standard serial ion isolation MS/MS experiments were observed for trimethylolpropane/methyl hexahydrophthalic anhydride. A 20-component sample derived from combinatorial synthesis was fragmented, and the template ion along with another key fragment ion was identified for each of the 20 components.

Solid phase selective separation and preconcentration of Cu(II) by Cu(II)-imprinted polymethacrylic microbeads.

PubMed

Dakova, Ivanka; Karadjova, Irina; Ivanov, Ivo; Georgieva, Ventsislava; Evtimova, Bisera; Georgiev, George

2007-02-12

Ion-imprinted polymer (IIP) particles are prepared by copolymerization of methacrylic acid as monomer, trimethylolpropane trimethacrylate as crosslinking agent and 2,2'-azo-bis-isobutyronitrile as initiator in the presence of Cu(II), a Cu(II)-4-(2-pyridylazo)resorcinol (Cu(II)-PAR) complex, and PAR only. A batch procedure is used for the determination of the characteristics of the Cu(II) solid phase extraction from the IIP produced. The results obtained show that the Cu(II)-PAR IIP has the greatest adsorption capacity (37.4 micromol g(-1) of dry copolymer) among the IIPs investigated. The optimal pH value for the quantitative preconcentration is 7, and full desorption is achieved by 1 M HNO(3). The selectivity coefficients (S(Cu/Me)) for Me=Ni(II), Co(II) are 45.0 and 38.5, respectively. It is established that Cu(II)-PAR IIPs can be used repeatedly without a considerable adsorption capacity loss. The determination of Cu(II) ions in seawater shows that the interfering matrix does not influence the preconcentration and selectivity values of the Cu(II)-PAR IIPs. The detection and quantification limits are 0.001 micromol L(-1) (3sigma) and 0.003 micromol L(-1) (6sigma), respectively.

Kinetic modeling of copper biosorption by immobilized biomass

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

Veglio, F.; Beolchini, F.; Toro, L.

1998-03-01

Biosorption of heavy metals is one of the most promising technologies involved in the removal of toxic metals from industrial waste streams and natural waters. The kinetic modeling of copper biosorption by Arthrobacter sp. immobilized in a hydroxyethyl methacrylate-based matrix is reported in this work. The resin-biomass complex (RBC) has been used for copper biosorption in different conditions according to a factorial experiment. Factors investigated were cross-linker (trimethylolpropane trimethacrylate) concentration, biomass concentration in the solid, and particles` granulometry. A maximum copper specific uptake of abut 7 mg of Cu/g of biomass (dry weight) has been observed, in the case ofmore » a RBC with the following characteristics: 2% (w/w) cross-linker concentration, 8% (w/w) biomass concentration, and 425--750 {micro}m granulometry. The shrinking core model has been used for the fitting of experimental data. A good fit has been found in the case of controlling intraparticle diffusion in all experimental trials. The copper diffusion coefficient in RBC has been estimated from the slope of the regression lines. Values obtained for the diffusion coefficients do not differ from one another with respect to the estimated standard error. An average apparent copper diffusion coefficient of about 3 {times} 10{sup {minus}6} cm{sup 2}/s has been found.« less

Preparation of polymer monolithic column functionalized by arsonic acid groups for mixed-mode capillary liquid chromatography.

PubMed

Qin, Zhang-Na; Yu, Qiong-Wei; Wang, Ren-Qi; Feng, Yu-Qi

2018-04-27

A mixed-mode polymer monolithic column functionalized by arsonic acid groups was prepared by single-step in situ copolymerization of monomers p-methacryloylaminophenylarsonic acid (p-MAPHA) and pentaerythritol triacrylate (PETA). The prepared poly(p-MAPHA-co-PETA) monolithic column has a homogeneous monolithic structure with good permeability and mechanical stability. Zeta potential measurements reveal that the monolithic stationary phase holds a negative surface charge when the mobile phase resides in the pH range of 3.0-8.0. The retention mechanisms of prepared monolithic column are explored by the separation of selected polycyclic aromatic hydrocarbons (PAHs), nucleosides, and three basic compounds. The results indicate that the column functions in three different separation modes associated with reversed-phase chromatography based on hydrophobic interaction, hydrophilic interaction chromatography, and cation-exchange chromatography. The column efficiency of prepared monolithic column is estimated to be 70,000 and 76,000 theoretical plates/m for thiourea and naphthalene, respectively, at a linear flow velocity of 0.85 mm/s using acetonitrile/H 2 O (85/15, v/v) as the mobile phase. Furthermore, an analysis of the retention factors obtained for the PAHs indicates that the prepared monolithic column exhibits good reproducibility with relative standard deviations of 2.9%, 4.0%, and 4.7% based on run-to-run injections, column-to-column preparation, and batch-to-batch preparation, respectively. Finally, we investigate the separation performance of the proposed monolithic column for select phenols, sulfonamides, nucleobases and nucleosides. Copyright © 2018 Elsevier B.V. All rights reserved.

Development of an in-house mixed-mode solid-phase extraction for the determination of 16 basic drugs in urine by High Performance Liquid Chromatography-Ion Trap Mass Spectrometry.

PubMed

Musile, Giacomo; Cenci, Lucia; Piletska, Elena; Gottardo, Rossella; Bossi, Alessandra M; Bortolotti, Federica

2018-07-27

The aim of the present work was to develop a novel in-house mixed-mode SPE sorbent to be used for the HPLC-Ion TrapMS determination of 16 basic drugs in urine. By using a computational modelling, a virtual monomer library was screened identifying three suitable functional monomers, methacrylic acid (MAA), itaconic acid (IA) and 2-acrylamide-2-methylpropane sulfonic acid (AMPSA), respectively. Three different sorbents were then synthetized based on these monomers, and using as cross-linker trimethylolpropane trimethacrylate (TMPTMA). The sorbent characterization analyses brought to the selection of the AMPSA based phase. Using this novel in-house sorbent, a SPE-HPLC-Ion TrapMS method for drug analysis in urine was validated proving to be selective and accurate and showing a sensitivity adequate for toxicological urine analysis. The comparison of the in-house mixed-mode SPE sorbent with two analogous commercial mixed-mode SPE phases showed that the first one was better not only in terms of process efficiency, but also in terms of quality-price rate. To the best of our knowledge, this is the first time in which an in-house SPE procedure has been applied to the toxicological analysis of a complex matrix, such as urine. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer/cryogel composites for solid-phase extraction of bisphenol A from river water and wine.

PubMed

Baggiani, Claudio; Baravalle, Patrizia; Giovannoli, Cristina; Anfossi, Laura; Giraudi, Gianfranco

2010-05-01

Superporous monolithic hydrogels (cryogel monoliths) are elastic, sponge-like materials that can be prepared in an aqueous medium through a cryotropic gelation technique. These monoliths show interesting properties for the development of high-throughput solid-phase extraction supports to treat large volumes of aqueous samples. In this work, a cryogel-supported molecularly imprinted solid-phase extraction approach for the endocrine disruptor bisphenol A (BPA) from river water and wine samples is presented. An imprinted polymer with molecular recognition properties for BPA was prepared in acetonitrile by thermal polymerization of a mixture of 4,4'-dihydroxy-2,2-diphenyl-1,1,1,3,3,3-trifluoropropane as a mimic template of BPA, 4-vinylpyridine and trimethylolpropane trimethacrylate in a molar ratio of 1 + 6 + 6. Fine imprinted particles (<10 microm) were embedded in a poly-acrylamide-co-N,N'-methylenbisacrylamide cryogel obtained by ammonium persulfate-induced cryopolymerization at -18 degrees C. The resulting monolithic gel was evaluated for its use as a sorbent support in an off-line solid-phase extraction approach to recover BPA from dilute aqueous samples with minimum pre-loading work-up. The optimized extraction protocol resulted in a reliable MISPE method suitable to selectively extract and preconcentrate BPA from river water and red wine samples, demonstrating the practical feasibility of cryogel-trapped imprinted polymers as solid-phase extraction materials.

Biodegradable products by lipase biocatalysis.

PubMed

Linko, Y Y; Lämsä, M; Wu, X; Uosukainen, E; Seppälä, J; Linko, P

1998-11-18

The interest in the applications of biocatalysis in organic syntheses has rapidly increased. In this context, lipases have recently become one of the most studied groups of enzymes. We have demonstrated that lipases can be used as biocatalyst in the production of useful biodegradable compounds. A number of examples are given. 1-Butyl oleate was produced by direct esterification of butanol and oleic acid to decrease the viscosity of biodiesel in winter use. Enzymic alcoholysis of vegetable oils without additional organic solvent has been little investigated. We have shown that a mixture of 2-ethyl-1-hexyl esters can be obtained in a good yield by enzymic transesterification from rapeseed oil fatty acids for use as a solvent. Trimethylolpropane esters were also similarly synthesized as lubricants. Finally, the discovery that lipases can also catalyze ester syntheses and transesterification reactions in organic solvent systems has opened up the possibility of enzyme catalyzed production of biodegradable polyesters. In direct polyesterification of 1,4-butanediol and sebacic acid, polyesters with a mass average molar mass of the order of 56,000 g mol-1 or higher, and a maximum molar mass of about 130,000 g mol-1 were also obtained by using lipase as biocatalyst. Finally, we have demonstrated that also aromatic polyesters can be synthesized by lipase biocatalysis, a higher than 50,000 g mol-1 mass average molar mass of poly(1,6-hexanediyl isophthalate) as an example.

Printable Solid-State Lithium-Ion Batteries: A New Route toward Shape-Conformable Power Sources with Aesthetic Versatility for Flexible Electronics.

PubMed

Kim, Se-Hee; Choi, Keun-Ho; Cho, Sung-Ju; Choi, Sinho; Park, Soojin; Lee, Sang-Young

2015-08-12

Forthcoming flexible/wearable electronic devices with shape diversity and mobile usability garner a great deal of attention as an innovative technology to bring unprecedented changes in our daily lives. From the power source point of view, conventional rechargeable batteries (one representative example is a lithium-ion battery) with fixed shapes and sizes have intrinsic limitations in fulfilling design/performance requirements for the flexible/wearable electronics. Here, as a facile and efficient strategy to address this formidable challenge, we demonstrate a new class of printable solid-state batteries (referred to as "PRISS batteries"). Through simple stencil printing process (followed by ultraviolet (UV) cross-linking), solid-state composite electrolyte (SCE) layer and SCE matrix-embedded electrodes are consecutively printed on arbitrary objects of complex geometries, eventually leading to fully integrated, multilayer-structured PRISS batteries with various form factors far beyond those achievable by conventional battery technologies. Tuning rheological properties of SCE paste and electrode slurry toward thixotropic fluid characteristics, along with well-tailored core elements including UV-cured triacrylate polymer and high boiling point electrolyte, is a key-enabling technology for the realization of PRISS batteries. This process/material uniqueness allows us to remove extra processing steps (related to solvent drying and liquid-electrolyte injection) and also conventional microporous separator membranes, thereupon enabling the seamless integration of shape-conformable PRISS batteries (including letters-shaped ones) into complex-shaped objects. Electrochemical behavior of PRISS batteries is elucidated via an in-depth analysis of cell impedance, which provides a theoretical basis to enable sustainable improvement of cell performance. We envision that PRISS batteries hold great promise as a reliable and scalable platform technology to open a new concept of cell architecture and fabrication route toward flexible power sources with exceptional shape conformability and aesthetic versatility.

Novel acyloxy derivatives of branched mono- and polyol esters of sal fat: multiviscosity grade lubricant base stocks.

PubMed

Kamalakar, Kotte; Sai Manoj, Gorantla N V T; Prasad, Rachapudi B N; Karuna, Mallampalli S L

2014-12-10

Sal fat, a nontraditional seed oil, was chemically modified to obtain base stocks with a wide range of specifications that can replace mineral oil base stocks. Sal fatty acids were enriched to 72.6% unsaturation using urea adduct method and reacted with branched mono alcohol, 2-ethylhexanol (2-EtH), and polyols namely neopentyl glycol (NPG) and trimethylolpropane (TMP) to obtain corresponding esters. The esters were hydroxylated and then acylated using propionic, butyric, and hexanoic anhydrides to obtain corresponding acylated derivatives. The acylated TMP esters exhibited very high viscosities (427.35-471.93 cSt at 40 °C) similar to those of BS 150 mineral oil base stock range, ISO VG 460, while the acylated NPG esters (268.81-318.84 cSt at 40 °C) and 2-EtH esters viscosities (20.94-24.44 cSt at 40 °C) exhibited viscosities in the range of ISO VG 320 and 22 respectively with good viscosity indices. Acylated NPG esters were found suitable for high temperature and acylated 2-ethylhexyl esters for low viscosity grade industrial applications. It was observed that the thermo-oxidative stabilities of all acylated products were found better compared to other vegetable oil based base stocks. Overall, all the sal fat based lubricant base stocks are promising candidates with a wide range of properties, which can replace most of the mineral oil base stocks with appropriate formulations.

Facile construction of macroporous hybrid monoliths via thiol-methacrylate Michael addition click reaction for capillary liquid chromatography.

PubMed

Lin, Hui; Ou, Junjie; Liu, Zhongshan; Wang, Hongwei; Dong, Jing; Zou, Hanfa

2015-01-30

A facile approach based on thiol-methacrylate Michael addition click reaction was developed for construction of porous hybrid monolithic materials. Three hybrid monoliths were prepared via thiol-methacrylate click polymerization by using methacrylate-polyhedral oligomeric silsesquioxane (POSS) (cage mixture, n=8, 10, 12, POSS-MA) and three multi-thiol crosslinkers, 1,6-hexanedithiol (HDT), trimethylolpropane tris(3-mercaptopropionate) (TPTM) and pentaerythritol tetrakis(3-mercaptopropionate) (PTM), respectively, in the presence of porogenic solvents (n-propanol and PEG 200) and a catalyst (dimethylphenylphosphine, DMPP). The obtained monoliths possessed high thermal and chemical stabilities. Besides, they all exhibited high column efficiencies and excellent separation abilities in capillary liquid chromatography (cLC). The highest column efficiency could reach ca. 195,000N/m for butylbenzene on the monolith prepared with POSS-MA and TPTM (monolith POSS-TPTM) in reversed-phase (RP) mode at 0.64mm/s. Good chromatographic performance were all achieved in the separations of polycyclic aromatic hydrocarbons (PAHs), phenols, anilines, EPA 610 as well as bovine serum albumin (BSA) digest. The high column efficiencies in the range of 51,400-117,000N/m (achieved on the monolith POSS-PTM in RP mode) convincingly demonstrated the high separation abilities of these thiol-methacrylate based hybrid monoliths. All the results demonstrated the feasibility of the phosphines catalyzed thiol-methacrylate Michael addition click reaction in fabrication of monolithic columns with high efficiency for cLC applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Doxorubicin-loaded micelles based on multiarm star-shaped PLGA-PEG block copolymers: influence of arm numbers on drug delivery.

PubMed

Ma, Guilei; Zhang, Chao; Zhang, Linhua; Sun, Hongfan; Song, Cunxian; Wang, Chun; Kong, Deling

2016-01-01

Star-shaped block copolymers based on poly(D,L-lactide-co-glycolide) (PLGA) and poly(ethylene glycol) (PEG) (st-PLGA-PEG) were synthesized with structural variation on arm numbers in order to investigate the relationship between the arm numbers of st-PLGA-PEG copolymers and their micelle properties. st-PLGA-PEG copolymers with arm numbers 3, 4 and 6 were synthesized by using different cores such as trimethylolpropane, pentaerythritol and dipentaerythritol, and were characterized by nuclear magnetic resonance and gel permeation chromatography. The critical micelle concentration decreased with increasing arm numbers in st-PLGA-PEG copolymers. The doxorubicin-loaded st-PLGA-PEG micelles were prepared by a modified nanoprecipitation method. Micellar properties such as particle size, drug loading content and in vitro drug release behavior were investigated as a function of the number of arms and compared with each other. The doxorubicin-loaded 4-arm PLGA-PEG micelles were found to have the highest cellular uptake efficiency and cytotoxicity compared with 3-arm PLGA-PEG micelles and 6-arm PLGA-PEG micelles. The results suggest that structural tailoring of arm numbers from st-PLGA-PEG copolymers could provide a new strategy for designing drug carriers of high efficiency. Structural tailoring of arm numbers from star shaped-PLGA-PEG copolymers (3-arm/4-arm/6-arm-PLGA-PEG) could provide a new strategy for designing drug carriers of high efficiency.

Hybrid molecularly imprinted poly(methacrylic acid-TRIM)-silica chemically modified with (3-glycidyloxypropyl)trimethoxysilane for the extraction of folic acid in aqueous medium.

PubMed

de Oliveira, Fernanda Midori; Segatelli, Mariana Gava; Tarley, César Ricardo Teixeira

2016-02-01

In the present study a hybrid molecularly imprinted poly(methacrylic acid-trimethylolpropane trimethacrylate)-silica (MIP) was synthesized and modified with (3-glycidyloxypropyl)trimethoxysilane (GPTMS) with posterior opening of epoxy ring to provide hydrophilic properties of material in the extraction of folic acid from aqueous medium. The chemical and structural aggregates of hybrid material were characterized by means of Fourier Transform Infrared (FT-IR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA) and textural data. Selectivity data of MIP were compared to non-imprinted polymer (NIP) through competitive sorption studies in the presence of caffeine, paracetamol or 4-aminobenzamide yielding relative selectivity coefficients (k′) higher than one unit, thus confirming the selective character of MIP even in the presence of structurally smaller compounds than the folic acid. The lower hydrophobic sorption by bovine serum albumin (BSA) in the MIP as compared to unmodified MIP proves the hydrophilicity of polymer surface by using GPTMS with opening ring. Under acid medium(pH 1.5) the sorption of folic acid onto MIP from batch experiments was higher than the one achieved for NIP. Equilibrium sorption of folic acid was reached at 120 min for MIP, NIP and MIP without GPTMS and kinetic sorption data were well described by pseudo-second-order, Elovich and intraparticle diffusion models. Thus, these results indicate the existence of different binding energy sites in the polymers and a complex mechanism consisting of both surface sorption and intraparticle transport of folic acid within the pores of polymers.

Ion-imprinted polymethacrylic microbeads as new sorbent for preconcentration and speciation of mercury.

PubMed

Dakova, Ivanka; Karadjova, Irina; Georgieva, Ventsislava; Georgiev, George

2009-04-30

Metal ion-imprinted polymer particles have been prepared by copolymerization of methacrylic acid as monomer, trimethylolpropane trimethacrylate as cross-linking agent and 2,2'-azobisisobutyronitrile as initiator, in the presence of Hg(II)-1-(2-thiazolylazo)-2-naphthol complex. The separation and preconcentration characteristics of the Hg-ion-imprinted microbeads for inorganic mercury have been investigated by batch procedure. The optimal pH value for the quantitative sorption is 7. The adsorbed inorganic mercury is easily eluted by 2 mL 4M HNO(3). The adsorption capacity of the newly synthesized Hg ion-imprinted microbeads is 32.0 micromol g(-1) for dry copolymer. The selectivity of the copolymer toward inorganic mercury (Hg(II)) ion is confirmed through the comparison of the competitive adsorptions of Cd(II), Co(II), Cu(II), Ni(II), Pb(II), Zn(II)) and high values of the selectivity and distribution coefficients have been calculated. Experiments performed for selective determination of inorganic mercury in mineral and sea waters showed that the interfering matrix does not influence the extraction efficiency of Hg ion-imprinted microbeads. The detection limit for inorganic mercury is 0.006 microg L(-1) (3 sigma), determined by cold vapor atomic adsorption spectrometry. The relative standard deviation varied in the range 5-9 % at 0.02-1 microg L(-1) Hg levels. The new Hg-ion-imprinted microbeads have been tested and applied for the speciation of Hg in river and mineral waters: inorganic mercury has been determined selectively in nondigested sample, while total mercury e.g. sum of inorganic and methylmercury, has been determined in digested sample.

Rational design of molecularly imprinted polymer: the choice of cross-linker.

PubMed

Muhammad, Turghun; Nur, Zohre; Piletska, Elena V; Yimit, Osmanjan; Piletsky, Sergey A

2012-06-07

The paper describes a rational approach for the selection of cross-linkers during the development of molecularly imprinted polymers (MIPs). As a model system for this research MIPs specific for the drug zidovudine (AZT) were designed and tested. Three cross-linkers trimethylolpropane trimethacrylate (TRIM), ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) were studied. The analogue of zidovudine (AZT) ester (AZT-ES) was used as a dummy template. The imprinting factors for all of the polymers in the static adsorption experiments were calculated. The data on the AZT adsorption by control polymers (CP), which were prepared with different cross-linkers without a functional monomer, was also analyzed. DVB was found to be more inert towards zidovudine than EGDMA and TRIM, which was confirmed by both molecular modelling and adsorption experiments. It was demonstrated that DVB-based polymers had a higher imprinting factor (I = 1.85) compared with other tested cross-linked polymers. It was suggested that the selection of the cross-linker should be based on the strength of the interaction with the template: the cross-linker which displays lower binding of the template should be preferential because it generates MIPs with lower non-specific binding and a higher imprinting factor, and therefore specificity. Which cross-linker to use for the preparation of any particular MIP can be determined by analysis of the interactions between the cross-linker and template. This could be done either virtually using computational modelling or by template adsorption using a small library of polymers prepared using different cross-linkers.

The effect of free radical inhibitor on the sensitized radiation crosslinking and thermal processing stabilization of polyurethane shape memory polymers.

PubMed

Hearon, Keith; Smith, Sarah E; Maher, Cameron A; Wilson, Thomas S; Maitland, Duncan J

2013-02-01

The effects of free radical inhibitor on the electron beam crosslinking and thermal processing stabilization of novel radiation crosslinkable polyurethane shape memory polymers (SMPs) blended with acrylic radiation sensitizers have been determined. The SMPs in this study possess novel processing capabilities-that is, the ability to be melt processed into complex geometries as thermoplastics and crosslinked in a secondary step using electron beam irradiation. To increase susceptibility to radiation crosslinking, the radiation sensitizer pentaerythritol triacrylate (PETA) was solution blended with thermoplastic polyurethane SMPs made from 2-butene-1,4-diol and trimethylhexamethylene diisocyanate (TMHDI). Because thermoplastic melt processing methods such as injection molding are often carried out at elevated temperatures, sensitizer thermal instability is a major processing concern. Free radical inhibitor can be added to provide thermal stabilization; however, inhibitor can also undesirably inhibit radiation crosslinking. In this study, we quantified both the thermal stabilization and radiation crosslinking inhibition effects of the inhibitor 1,4-benzoquinone (BQ) on polyurethane SMPs blended with PETA. Sol/gel analysis of irradiated samples showed that the inhibitor had little to no inverse effects on gel fraction at concentrations of 0-10,000 ppm, and dynamic mechanical analysis showed only a slight negative correlation between BQ composition and rubbery modulus. The 1,4-benzoquinone was also highly effective in thermally stabilizing the acrylic sensitizers. The polymer blends could be heated to 150°C for up to five hours or to 125°C for up to 24 hours if stabilized with 10,000 ppm BQ and could also be heated to 125°C for up to 5 hours if stabilized with 1000 ppm BQ without sensitizer reaction occurring. We believe this study provides significant insight into methods for manipulation of the competing mechanisms of radiation crosslinking and thermal stabilization of radiation sensitizers, thereby facilitating further development of radiation crosslinkable thermoplastic SMPs.

The effect of free radical inhibitor on the sensitized radiation crosslinking and thermal processing stabilization of polyurethane shape memory polymers

NASA Astrophysics Data System (ADS)

Hearon, Keith; Smith, Sarah E.; Maher, Cameron A.; Wilson, Thomas S.; Maitland, Duncan J.

2013-02-01

The effects of free radical inhibitor on the electron beam crosslinking and thermal processing stabilization of novel radiation crosslinkable polyurethane shape memory polymers (SMPs) blended with acrylic radiation sensitizers have been determined. The SMPs in this study possess novel processing capabilities—that is, the ability to be melt processed into complex geometries as thermoplastics and crosslinked in a secondary step using electron beam irradiation. To increase susceptibility to radiation crosslinking, the radiation sensitizer pentaerythritol triacrylate (PETA) was solution blended with thermoplastic polyurethane SMPs made from 2-butene-1,4-diol and trimethylhexamethylene diisocyanate (TMHDI). Because the thermoplastic melt processing methods such as injection molding are often carried out at elevated temperatures, sensitizer thermal instability is a major processing concern. Free radical inhibitor can be added to provide thermal stabilization; however, inhibitor can also undesirably inhibit radiation crosslinking. In this study, we quantified both the thermal stabilization and radiation crosslinking inhibition effects of the inhibitor 1,4-benzoquinone (BQ) on polyurethane SMPs blended with PETA. Sol/gel analysis of irradiated samples showed that the inhibitor had little to no inverse effects on gel fraction at concentrations of 0-10,000 ppm, and dynamic mechanical analysis showed only a slight negative correlation between BQ composition and rubbery modulus. The 1,4-benzoquinone was also highly effective in thermally stabilizing the acrylic sensitizers. The polymer blends could be heated to 150 °C for up to 5 h or to 125 °C for up to 24 h if stabilized with 10,000 ppm BQ and could also be heated to 125 °C for up to 5 h if stabilized with 1000 ppm BQ without sensitizer reaction occurring. We believe this study provides significant insight into methods for manipulation of the competing mechanisms of radiation crosslinking and thermal stabilization of radiation sensitizers, thereby facilitating further development of radiation crosslinkable thermoplastic SMPs.

Fast preparation of hybrid monolithic columns via photo-initiated thiol-yne polymerization for capillary liquid chromatography.

PubMed

Ma, Shujuan; Zhang, Haiyang; Li, Ya; Li, Yanan; Zhang, Na; Ou, Junjie; Ye, Mingliang; Wei, Yinmao

2018-02-23

Although several approaches have been developed to fabricate hybrid monoliths, it would still take a few hours to finish the formation of monoliths. Herein, photo-initiated thiol-yne polymerization was first adopted to in situ fabricate hybrid monoliths within the confines of UV-transparent fused-silica capillary. A silicon-containing diyne (1,3-diethynyltetramethyl-disiloxane, DYDS) was copolymerized with three multithiols, 1,6-hexanedithiol, trimethylolpropane tris(3-mercaptopropionate) and pentaerythriol tetrakis(3-mercaptopropionate), by using a binary porogenic system of diethylene glycol diethyl ether (DEGDE)/poly(ethylene glycol) (PEG200) within 10 min. Several characterizations of three hybrid monoliths (assigned as I, II and III, respectively) were performed. The results showed that these hybrid monoliths possessed bicontinuous porous structure, which was remarkably different from that via typical free-radical polymerization. The highest column efficiency of 76,000 plates per meter for butylbenzene was obtained on the column I in reversed-phase liquid chromatography (RPLC). It was observed that the efficiencies for strong-retained butylbenzene were almost close to those of weak-retained benzene, indicating a retention-independent efficient performance of small molecules on hybrid column I. The surface area of this hybrid monolith was very small in the dry state (less than 10.0 m 2 /g), and the chromatographic behavior of hybrid monolithic columns would be possibly explained by radical-mediated step-growth process of thiol-yne polymerization. Finally, the column I was applied for separation of BSA tryptic digest by cLC-MS/MS, indicating satisfactory separation ability for complicated samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Biomimetic piezoelectric quartz crystal sensor with chloramphenicol-imprinted polymer sensing layer.

PubMed

Ebarvia, Benilda S; Ubando, Isaiah E; Sevilla, Fortunato B

2015-11-01

The measurement of banned antibiotic like chloramphenicol is significant for customer protection and safety. The presence of residual antibiotics in foods and food products of animal origin could pose as health hazards and affect food quality for global acceptance. In this study, the potential of a chloramphenicol sensor based on molecularly imprinted polymer (MIP) coupled with a piezoelectric quartz crystal was explored. The MIP was prepared by precipitation polymerization at 60 °C. Methacrylic acid was used as monomer, trimethylolpropane trimethacrylate (TRIM) as crosslinker, and chloramphenicol as the template. Template removal on the resulting polymer was done by extraction using methanol-acetic acid. Characterization of the MIP and NIP were conducted by spectroscopic and microscopic methods. These further supported the imprinting and rebinding process of chloramphenicol to the polymer matrix. The chloramphenicol sensor was devised by spin-coating onto one side of the 10 MHz AT-cut quartz crystal the MIP suspension in polyvinylchloride-tetrahydrofuran (6:2:1 w/w/v) solution. Optimization of sensor response was performed by varying the type of cross-linker, amount of MIP sensing layer, curing time, and pH. The sensor exhibited good sensitivity of about 73 Hz/log (conc., µg mL(-1)) and good repeatability (rsd<10%). A linear relationship (r(2)=0.9901) between frequency shift and chloramphenicol concentration in the range of 1×10(-6) up to 1×10(-1) µg/mL was obtained. The sensor response was highly selective to chloramphenicol than with other compounds of similar chemical structures. Acceptable percent recovery was obtained for real sample analysis using the sensor. The proposed sensor could be a promising low cost and highly sensitive approach for residual chloramphenicol quantification in food products. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of Opalescence(®) bleaching gels on the elution of bulk-fill composite components.

PubMed

Schuster, Lena; Reichl, Franz-Xaver; Rothmund, Lena; He, Xiuli; Yang, Yang; Van Landuyt, Kirsten L; Kehe, Kai; Polydorou, Olga; Hickel, Reinhard; Högg, Christof

2016-02-01

Bleaching treatments can affect release of components from conventional composites. In this continuing study the influence of two different bleaching gels on the elution of bulk-fill composite components was investigated. The composites Tetric EvoCeram(®) Bulk Fill, QuiXFil™ and X-tra fil were treated with the bleaching gels Opalescence PF 15% (PF 15%) for 5 h and PF 35% (PF 35%) for 30 min and then stored in methanol and water for 24 h and 7 d. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). Unbleached specimens were used as control group. A total of 7 different elutable substances have been identified from the investigated composites after bleaching-treatment. Three of them were methacrylates: 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA) and trimethylolpropane trimethacrylate (TMPTMA). Compared to the unbleached controls an increase in elution after PF 15%-treatment of following compounds was found: HEMA (Tetric EvoCeram(®) Bulk Fill), TEGDMA (QuiXFil™, X-tra fil) and 4-N,N-dimethylaminobenzoic acid butyl ethoxy ester (DMABEE) (Tetric EvoCeram(®) Bulk Fill, QuiXFil™, X-tra fil). Following compounds showed a reduction in elution after PF 35%-treatment compared to controls: TEGDMA (QuiXFil™) and DMABEE (Tetric EvoCeram(®) Bulk Fill). The highest concentration of HEMA was 0.22 mmol/l (Tetric EvoCeram(®) Bulk Fill, methanol, 7 d, PF 15%), the highest concentration of TEGDMA was 0.3 mmol/l (X-tra fil, water, 7 d, PF 15%) and the highest concentration of DMABEE was 0.05 mmol/l (QuiXFil™, water, 7 d, PF 35%). PF 15% and PF 35% can lead to reduced and/or increased elution of some bulk-fill components, compared to unbleached bulk-fill composites. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Solid-phase extraction of the alcohol abuse biomarker phosphatidylethanol using newly synthesized polymeric sorbent materials containing quaternary heterocyclic groups.

PubMed

Duarte, Mariana; Jagadeesan, Kishore Kumar; Billing, Johan; Yilmaz, Ecevit; Laurell, Thomas; Ekström, Simon

2017-10-13

Phosphatidylethanol (PEth) is an interesting biomarker finding increased use for detecting long term alcohol abuse with high specificity and sensitivity. Prior to detection, sample preparation is an unavoidable step in the work-flow of PEth analysis and new protocols may facilitate it. Solid-phase extraction (SPE) is a versatile sample preparation method widely spread in biomedical laboratories due to its simplicity of use and the possibility of automation. In this work, SPE was used for the first time to directly extract PEth from spiked human plasma and spiked human blood. A library of polymeric SPE materials with different surface functionalities was screened for PEth extraction in order to identify the surface characteristics that control PEth retention and recovery. The plasma samples were diluted 1:10 (v/v) in water and spiked at different concentrations ranging from 0.3 to 5μM. The library of SPE materials was then evaluated using the proposed SPE method and detection was done by LC-MS/MS. One SPE material efficiently retained and recovered PEth from spiked human plasma. With this insight, four new SPE materials were formulated and synthesized based on the surface characteristics of the best SPE material found in the first screening. These new materials were tested with spiked human blood, to better mimic a real clinical sample. All the newly synthetized materials outperformed the pre-existing commercially available materials. Recovery values for the new SPE materials were found between 29.5% and 48.6% for the extraction of PEth in spiked blood. A material based on quaternized 1-vinylimidazole with a poly(trimethylolpropane trimethacrylate) backbone was found suitable for PEth extraction in spiked blood showing the highest analyte recovery in this experiment, 48.6%±6.4%. Copyright © 2017 Elsevier B.V. All rights reserved.

Separation of Rebaudiana A from Steviol glycoside using a polymeric adsorbent with multi-hydrogen bonding in a non-aqueous system.

PubMed

Ba, Jing; Zhang, Na; Yao, Lijuan; Ma, Ning; Wang, Chunhong

2014-11-15

Rebaudioside A (RA) and stevioside (SS) are the primary effective glycoside components in Stevia Rebaudiana. The RA glycoside is sweeter, and it tastes similarly to sucrose. Because extracts with a high RA content can be used as natural sweeteners for food additives approved by the FAO and FDA, RA should generate high market demand. In this study, an efficient method for separating RA was established based on the synergistic multi-hydrogen bonding interaction between a polymeric adsorbent and the RA glycoside. To overcome the destruction of the hydrophobic affinity required for the selective adsorption of RA, an innovative non-aqueous environment was established for adsorption and separation. To this end, an initial polymeric adsorbent composed of a glycidyl methacrylate and trimethylolpropane trimethacrylate (GMA-co-TMPTMA) copolymer matrix was synthesized, and polyethylene polyamine was employed as a functional reagent designed to react with the epoxy group on GME-co-TMPTMA to form a highly selective macroporous adsorbent. The effects of the different functional reagents and the solvent polarity on the adsorption selectivity for RA and SS, respectively, were investigated. Matching the structure of the polyethylene polyamine and sugar ligand on the glycoside molecule was essential in ensuring that the maximum synergistic interaction between adsorbent and adsorbate would be achieved. Moreover, the hydrogen-bonding force was observed to increase when the polarity of the adsorption solvent decreased. Therefore, among the synthesized macroporous polymeric adsorbents, the GTN4 adsorbent-bonding tetraethylenepentamine functional group provided the best separation in an n-butyl alcohol solution. Under the optimized gradient elution conditions, RA and SS can be effectively separated, and the contents of RA and SS increased from 33.5% and 51.5% in the initial crude extract to 95.4% and 78.2% after separation, respectively. Compared to conventional methods, the adsorption-desorption process is more advanced due to its procedural simplicity, low cost and adaptability for industrial production. Copyright © 2014 Elsevier B.V. All rights reserved.

Water-Stable In(III)-Based Metal-Organic Frameworks with Rod-Shaped Secondary Building Units: Single-Crystal to Single-Crystal Transformation and Selective Sorption of C2H2 over CO2 and CH4.

PubMed

Guo, Zhen-Ji; Yu, Jiamei; Zhang, Yong-Zheng; Zhang, Jian; Chen, Ya; Wu, Yufeng; Xie, Lin-Hua; Li, Jian-Rong

2017-02-20

Three new water-stable In(III)-based metal-organic frameworks, namely, [In 3 (TTTA) 2 (OH) 3 (H 2 O)]·(DMA) 3 (BUT-70, DMA = N,N-dimethylacetamide), [In 3 (TTTA) 2 (CH 3 O) 3 ] (BUT-70A), and [In 3 (TTTA) 2 (OH) 3 ] (BUT-70B), with rod-shaped secondary building units (SBUs) and an new acrylate-based ligand, (2E,2'E,2″E)-3,3',3″-(2,4,6-trimethylbenzene-1,3,5-triyl)-triacrylate (TTTA 3- ) were obtained and structurally characterized. BUT-70A and -70B were generated in a single-crystal to single-crystal transformation fashion from BUT-70 through guest exchange followed by their removal. The solvents used for guest exchange were methanol and dichloromethane, respectively. Single-crystal structure analyses show that the guest exchange and removal process is accompanied by the substitution of coordinated water molecules of In(III) centers with uncoordinated carboxylate O atoms of TTTA 3- ligands. Moreover, hydroxyl groups bridging two In(III) centers are also replaced by methoxyl groups in the transformation from BUT-70 to -70A. Overall, three metal-organic frameworks (MOFs) are constructed by infinite chains consisting of corner-sharing InO 4 (OR) 2 (R = H or Me) octahedral entities, which are interconnected by TTTA 3- ligands to form three-dimensional frameworks. Unlike most reported MOFs with infinite chains as SBUs, such as well-known MIL-53 and M-MOF-74, which have one-dimensional channels along the chain direction, the BUT-70 series contain two-dimensional intersecting channels. The Brunauer-Emmett-Teller surface area and pore volume of BUT-70A were estimated to be 460 m 2 g -1 and 0.18 cm 3 g -1 , respectively, which are obviously lower than those of BUT-70B (695 m 2 g -1 and 0.29 cm 3 g -1 ). Gas adsorption experiments demonstrated that BUT-70A and -70B are able to selectively adsorb C 2 H 2 over CO 2 and CH 4 . At 1 atm and 298 K, BUT-70A uptakes 3.1 mmol g -1 C 2 H 2 , which is 3.6 times that of the CO 2 uptake and 7.2 times that of the CH 4 uptake. Compared with BUT-70A, BUT-70B presents an even higher C 2 H 2 uptake of 3.9 mmol g -1 at the same conditions, but slightly lower Ideal Adsorbed Solution Theory C 2 H 2 /CO 2 and C 2 H 2 /CH 4 selectivities.

Green polymer chemistry: Synthesis of poly(disulfide) polymers and networks

NASA Astrophysics Data System (ADS)

Rosenthal-Kim, Emily Quinn

The disulfide group is unique in that it presents a covalent bond that is easily formed and cleaved under certain biological conditions. While the ease of disulfide bond cleavage is often harnessed as a method of biodegradation, the ease of disulfide bond formation as a synthetic strategy is often overlooked. The objective this research was to synthesize poly(disulfide) polymers and disulfide crosslinked networks from a green chemistry approach. The intent of the green chemistry approach was to take advantage of the mild conditions applicable to disulfide bond synthesis from thiols. With anticipated use as biomaterials, it was also desired that the polymer materials could be degraded under biological conditions. Here, a new method of poly(disulfide) polymer synthesis is introduced which was inspired by the reaction conditions and reagents found in Nature. Ambient temperatures and aqueous mixtures were used in the new method. Hydrogen peroxide, one of the Nature's most powerful oxidizing species was used as the oxidant in the new polymerization reaction. The dithiol monomer, 3,6-dioxa-1,8-octanedithiol was first solubilized in triethylamine, which activated the thiol groups and made the monomer water soluble. At room temperature, the organic dithiol/amine solution was then mixed with dilute aqueous hydrogen peroxide (3% by weight) to make the poly(disulfide) polymers. The presence of a two phase system (organic and aqueous phases) was critical to the polymerization reaction. As the reaction progresses, a third, polymer phase appeared. At ambient temperatures and above, this phase separated from the reaction mixture and the polymer product was easily removed from the reaction solution. These polymers reach Mn > 250,000 g/mol in under two hours. Molecular weight distributions were between 1.5 and 2.0. Reactions performed in an ice bath which remain below room temperature contain high molecular weight polymers with Mn ≈ 120,000 g/mol and have a molecular weight distribution of around 1.15. However, the majority of the product consists of low molecular weight cyclic poly(disulfide) oligomers. In reactions maintained below 18°C, the organic components were miscible in the aqueous hydrogen peroxide and a milky emulsion was produced. The polymers were degraded using the disulfide-specific reducing agent, dithiothreitol. Poly(disulfide) polymer networks were also synthesized in a two-phase system. Due to the poor solubility of the crosslinker, trimethylolpropane tris(2-mercaptopropionate, organic solvents were required to obtain consistent networks. The networks were degraded using dithiothreitol in tetrahydrofuran. The networks were stable under aqueous reducing conditions. The disulfide-bearing biochemical, alpha-lipoic acid, was investigated as monomer for the new method of poly(disulfide) polymer synthesis. It was also polymerized thermally and by a new interfacial method that proceeds at the air-water interface. Polymer products were often too large to be characterized by SEC (Mn > 1,000,000 g/mol). A poly(alpha-LA) polymer sample showed mass loss in aqueous solutions of glutathione at pH = 5.2 which was used to model cytosolic conditions. Poly(alpha-LA) was decorated with PEG (2,000 g/mol) in an esterification reaction catalyzed by Candida antarctica lipase B (CALB). The decorated polymers were imaged using AFM which revealed branch-like structures. To make new alpha-lipoic acid based monomers and macromonomers, CALB-catalyzed esterification, was used to conjugate alpha-lipoic acid to a variety of glycols including: diethylene glycol monomethyl ether, tetraethylene glycol, hexaethylene glycol, and poly(ethylene glycol). The products were verified using NMR spectroscopy and mass spectrometry.