Science.gov

Sample records for ether-maleic anhydride polymer

  1. Improved lithographic performance for resists based on polymers having a vinyl ether-maleic anhydride (VEMA) backbone

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Woo; Choi, Sang-Jun; Jung, Dong-Won; Lee, Sook; Lee, Sung-Ho; Kang, Yool; Woo, Sang-Gyun; Moon, Joo-Tae; Kavanagh, Robert J.; Barclay, George G.; Orsula, George W.; Mattia, Joe; Caporale, Stefan; Adams, Timothy G.; Tanaka, Tsutomu; Kang, Doris

    2001-08-01

    ArF lithography, in combination with chemically amplified resists, has been investigated as one of the most promising technologies for producing patterns below 100 nm. In considering the polymer matrix for 193 nm photoresist applications, factors such as sensitivity, transparency to 193 nm radiation, adhesion to substrate, dry etch resistance, ease of synthesis, and availability of monomers are very critical. In these respects, remarkable progress has been made in development of ArF resist material. Polymers of acrylic and methacrylic esters show good imaging performance at 193 nm, but have insufficient dry-etch resistance under oxide or nitride etch condition. On the other hand, cyclic olefin-maleic anhydride (COMA) alternating copolymers exhibit good dry etch resistance, but have poor resolution capability. We previously reported a new platform, based on a vinyl ether-maleic anhydride (VEMA) alternating polymer system, that demonstrated both good resolution and high dry etch resistance. In this paper, VEMA systems with improved lithographic performance are presented. The new platform (VEMA) showed good performance in resolution, depth of focus (DOF), iso-dense bias, and post-etch roughness. With conventional illumination (NA=0.6, sigma=0.7), 120 nm dense line/space patterns with 0.4 (mu) M DOF were resolved. And 90 nm L/S patterns 0.6 (mu) M DOF were resolved with off-axis illumination (NA=0.63). Another important factor to be considered for the dry-etch process is post-etch roughness. In the case of VEMA system a clean surface was observed after etch under oxide, nitride, and poly conditions. The VEMA resist system is regarded as one of the most production-worthy material for real device manufacture.

  2. 78 FR 76567 - Tall Oil, Polymer With Polyethylene Glycol and Succinic Anhydride Monopolyisobutylene Derivs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-18

    ... AGENCY 40 CFR Part 180 Tall Oil, Polymer With Polyethylene Glycol and Succinic Anhydride... oil, polymer with polyethylene glycol and succinic anhydride monopolyisobutylene derivs. (CAS Reg. No... residues of tall oil, polymer with polyethylene glycol and succinic anhydride monopolyisobutylene...

  3. 40 CFR 721.10038 - Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Trimellitic anhydride, polymer with... Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol (generic... identified generically as trimellitic anhydride, polymer with substituted glycol, alkyl phenols...

  4. 40 CFR 721.10038 - Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Trimellitic anhydride, polymer with... Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol (generic... identified generically as trimellitic anhydride, polymer with substituted glycol, alkyl phenols...

  5. 40 CFR 721.10038 - Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Trimellitic anhydride, polymer with... Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol (generic... identified generically as trimellitic anhydride, polymer with substituted glycol, alkyl phenols...

  6. 40 CFR 721.10038 - Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Trimellitic anhydride, polymer with... Trimellitic anhydride, polymer with substituted glycol, alkyl phenols and ethoxylated nonylphenol (generic... identified generically as trimellitic anhydride, polymer with substituted glycol, alkyl phenols...

  7. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine (PMN...

  8. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine (PMN...

  9. Imide Oligomers Endcapped with Phenylethynl Phthalic Anhydrides and Polymers Therefrom

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1998-01-01

    Controlled molecular weight phenylethynyl terminated imide oligomers (PETIs) have been prepared by the cyclodehydration of precursor phenylethynyl terminated amic acid oligomers. Amino terminated amic acid oligomers are prepared from the reaction of dianhydride(s) with an excess of diamine(s) and subsequently endcapped with phenylethynyl phthalic anhydride(s) (PEPA). The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N.N-dimethylacetamide under nitrogen at room temperature. The amic acid oligomers are subsequently cyclodehydrated either thermally or cheznicauy to the corresponding imide oligomers. Direct preparation of PETIs from the reaction of dianhydxide(s) with an excess of diamine(s) and endcapped with phenylethynyl phthalic anhydride(s) has been performed in m-cresol. Phenylethynyl phthalic anhydrides are synthesized by the palladium catalyzed reaction of phenylacetylene with bromo substituted phthalic anhydrides in triethylamine. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  10. Imide oligomers endcapped with phenylethynyl phthalic anhydrides and polymers therefrom

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Smith, Jr., Joseph G. (Inventor)

    1996-01-01

    Controlled molecular weight phenylethynyl terminated imide oligomers (PETIs) have been prepared by the cyclodehydration of precursor phenylethynyl terminated amic acid oligomers. Amino terminated amic acid oligomers are prepared from the reaction of dianhydride(s) with an excess of diamine(s) and subsequently endcapped with phenylethynyl phthalic anhydride(s) (PEPA). The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide under nitrogen at room temperature. The amic acid oligomers are subsequently cyclodehydrated either thermally or chemically to the corresponding imide oligomers. Direct preparation of PETIs from the reaction of dianhydride(s) with an excess of diamine(s) and endcapped with phenylethynyl phthalic anhydride(s) has been performed in m-cresol. Phenylethynyl phthalic anhydrides are synthesized by the palladium catalyzed reaction of phenylacetylene with bromo substituted phthalic anhydrides in triethylamine. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  11. Prolonged Hypocalcemic Effect by Pulmonary Delivery of Calcitonin Loaded Poly(Methyl Vinyl Ether Maleic Acid) Bioadhesive Nanoparticles

    PubMed Central

    Varshosaz, J.; Minaiyan, M.; Forghanian, M.

    2014-01-01

    The purpose of the present study was to design a pulmonary controlled release system of salmon calcitonin (sCT). Therefore, poly(methyl vinyl ether maleic acid) [P(MVEMA)] nanoparticles were prepared by ionic cross-linking method using Fe2+ and Zn2+ ions. Physicochemical properties of nanoparticles were studied in vitro. The stability of sCT in the optimized nanoparticles was studied by electrophoretic gel method. Plasma calcium levels until 48 h were determined in rats as pulmonary-free sCT solution or nanoparticles (25 μg·kg−1), iv solution of sCT (5 μg·kg−1), and pulmonary blank nanoparticles. The drug remained stable during fabrication and tests on nanoparticles. The optimized nanoparticles showed proper physicochemical properties. Normalized reduction of plasma calcium levels was at least 2.76 times higher in pulmonary sCT nanoparticles compared to free solution. The duration of hypocalcemic effect of pulmonary sCT nanoparticles was 24 h, while it was just 1 h for the iv solution. There was not any significant difference between normalized blood calcium levels reduction in pulmonary drug solution and iv injection. Pharmacological activity of nanoparticles after pulmonary delivery was 65% of the iv route. Pulmonary delivery of P(MVEMA) nanoparticles of sCT enhanced and prolonged the hypocalcemic effect of the drug significantly. PMID:24701588

  12. XPS depth profiling of derivatized amine and anhydride plasma polymers: Evidence of limitations of the derivatization approach

    NASA Astrophysics Data System (ADS)

    Manakhov, Anton; Michlíček, Miroslav; Felten, Alexandre; Pireaux, Jean-Jacques; Nečas, David; Zajíčková, Lenka

    2017-02-01

    The quantitative analysis of the chemistry at the surface of functional plasma polymers is highly important for the optimization of their deposition conditions and, therefore, for their subsequent applications. The chemical derivatization of amine and carboxyl-anhydride layers is a well-known technique already applied by many researchers, notwithstanding the known drawback of the derivatization procedures like side or uncomplete reactions that could lead to "unreliable" results. In this work, X-ray photoelectron spectroscopy (XPS) combined with depth profiling with argon clusters is applied for the first time to study derivatized amine and carboxyl-anhydride plasma polymer layers. It revealed an additional important parameter affecting the derivatization reliability, namely the permeation of the derivatizing molecule through the target analysed layer, i.e. the composite effect of the probe molecule size and the layer porosity. Amine-rich films prepared by RF low pressure plasma polymerization of cyclopropylamine were derivatized with trifluoromethyl benzaldehide (TFBA) and it was observed by that the XPS-determined NH2 concentration depth profile is rapidly decreasing over top ten nanometers of the layer. The anhydride-rich films prepared by atmospheric plasma co-polymerization of maleic anhydride and C2H2 have been reacted with, parafluoroaniline and trifluoroethyl amine. The decrease of the F signal in top surface layer of the anhydride films derivatized by the "large" parafluoroaniline was observed similarly as for the amine films but the derivatization with the smaller trifluoroethylamine (TFEA) led to a more homogenous depth profile. The data analysis suggests that the size of the derivatizing molecule is the main factor, showing that the very limited permeation of the TFBA molecule can lead to underestimated densities of primary amines if the XPS analysis is solely carried out at a low take-off angle. In contrast, TFEA is found to be an efficient

  13. Role of Cellulose Nanocrystals on the Microstructure of Maleic Anhydride Plasma Polymer Thin Films.

    PubMed

    Brioude, Michel M; Roucoules, Vincent; Haidara, Hamidou; Vonna, Laurent; Laborie, Marie-Pierre

    2015-07-01

    Recently, it was shown that the microstructure of a maleic anhydride plasma polymer (MAPP) could be tailored ab initio by adjusting the plasma process parameters. In this work, we aim to investigate the ability of cellulose nanocrystals (CNCs) to induce topographical structuration. Thus, a new approach was designed based on the deposition of MAPP on CNCs model surfaces. The nanocellulosic surfaces were produced by spin-coating the CNC suspension on a silicon wafer substrate and on a hydrophobic silicon wafer substrate patterned with circular hydrophilic microsized domains (diameter of 86.9 ± 4.9 μm), resulting in different degrees of CNC aggregation. By depositing the MAPP over these surfaces, it was possible to observe that the surface fraction of nanostructures increased from 20% to 35%. This observation suggests that CNCs can act as nucleation points resulting in more structures, although a critical density of the CNCs is required.

  14. New polymers for 193-nm single-layer resists based on substituted cycloolefins/maleic anhydride resins

    NASA Astrophysics Data System (ADS)

    Rushkin, Ilya L.; Houlihan, Francis M.; Kometani, Janet M.; Hutton, Richard S.; Timko, Allen G.; Reichmanis, Elsa; Nalamasu, Omkaram; Gabor, Allen H.; Medina, Arturo N.; Slater, Sydney G.; Neisser, Mark O.

    1999-06-01

    A series of new polymers for 193 nm single layer resist based on maleic anhydride/cycloolefin systems with minimum amount of acrylate units were synthesized. In order to minimize the acrylate content, the cycloolefin moiety of the polymers was functionalized with side groups designed to either promotes adhesion to silicon substrate and/or impart the imaging functionality. All polymers were prepared by free-radical polymerization in moderate to high yields and were characterized by variety of techniques. The initial lithographic evaluation of the new resists was carried out. It was found that acrylates can be successfully replaced with appropriately substituted cycloolefins to provide good resolution. The etch resistance of the new materials generally improves with increase in cycloolefin content. The Onishi and Kunz type plots will be discussed.

  15. Effect of Phthalic Anhydride Modified Soy Protein on Viscoelastic Properties of Polymer Composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phthalic anhydride (PA) modified soy protein isolates (SPI), both hydrolyzed and un-hydrolyzed, are investigated as reinforcement fillers in styrene-butadiene (SB) composites. The modification of SPI by PA increases the number of carboxylic acid functional groups on the protein surface and therefor...

  16. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... maleic anhydride monomer content. Residual maleic anhydride monomer content shall be determined by a gas chromatographic method titled “Determination of Residual Maleic Anhydride in Polymers by Gas...

  17. Development of a guided bone regeneration device using salicylic acid-poly(anhydride-ester) polymers and osteoconductive scaffolds.

    PubMed

    Mitchell, Ashley; Kim, Brian; Cottrell, Jessica; Snyder, Sabrina; Witek, Lukasz; Ricci, John; Uhrich, Kathryn E; O'Connor, J Patrick

    2014-03-01

    Successful repair of craniofacial and periodontal tissue defects ideally involves a combined therapy that includes inflammation modulation, control of soft tissue infiltration, and bone regeneration. In this study, an anti-inflammatory polymer, salicylic acid-based poly(anhydride-ester) (SAPAE) and a three-dimensional osteoconductive ceramic scaffold were evaluated as a combined guided bone regeneration (GBR) system for concurrent control of inflammation, soft tissue ingrowth, and bone repair in a rabbit cranial defect model. At time periods of 1, 3, and 8 weeks, five groups were compared: (1) scaffolds with a solid ceramic cap (as a GBR structure); (2) scaffolds with no cap; (3) scaffolds with a poly(lactide-glycolide) cap; (4) scaffolds with a slow release SAPAE polymer cap; and (5) scaffolds with a fast release SAPAE polymer cap. Cellular infiltration and bone formation in these scaffolds were evaluated to assess inflammation and bone repair capacity of the test groups. The SAPAE polymers suppressed inflammation and displayed no deleterious effect on bone formation. Additional work is warranted to optimize the anti-inflammatory action of the SAPAE, GBR suppression of soft tissue infiltration, and stimulation of bone formation in the scaffolds and create a composite device for successful repair of craniofacial and periodontal tissue defects.

  18. 40 CFR 721.10316 - Dicyclopentadiene polymer with maleic anhydride and alkyl alcohols (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Dicyclopentadiene polymer with maleic... Significant New Uses for Specific Chemical Substances § 721.10316 Dicyclopentadiene polymer with maleic.... (1) The chemical substance identified generically as dicyclopentadiene polymer with maleic...

  19. 40 CFR 721.10316 - Dicyclopentadiene polymer with maleic anhydride and alkyl alcohols (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Dicyclopentadiene polymer with maleic... Significant New Uses for Specific Chemical Substances § 721.10316 Dicyclopentadiene polymer with maleic.... (1) The chemical substance identified generically as dicyclopentadiene polymer with maleic...

  20. 40 CFR 721.10316 - Dicyclopentadiene polymer with maleic anhydride and alkyl alcohols (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Dicyclopentadiene polymer with maleic... Significant New Uses for Specific Chemical Substances § 721.10316 Dicyclopentadiene polymer with maleic.... (1) The chemical substance identified generically as dicyclopentadiene polymer with maleic...

  1. Effects of Secondary Polymer Covalently Attached to Monodisperse, Poly(maleic anhydride-styrene)-Modified Colloidal Silica on Dispersibility in Organic Solvent.

    PubMed

    Yoshinaga; Shimada; Nishida; Komatsu

    1999-06-15

    Effects of surface-grafted polymer on the dispersibility of polymer-silica composite particles in ethyl acetate-methanol cosolvent were investigated. The composite particles were prepared by a two-step modification of monodisperse colloidal silica (120 nm in diameter). Modifications were carried out by first reacting the surface silanol of the colloidal silica with maleic anhydride-styrene copolymer silane coupling agent to prevent aggregation and then grafting, in acetone or tetrahydrofuran, amino group-terminated poly(methyl acrylate), poly(methyl methacrylate), or polystyrene to the maleic anhydride moiety on the surface. For poly(methyl acrylate) and poly(methyl methacrylate) graftings, composite particles with long polymer chains aggregated in methanol-rich cosolvent due to insoluble secondary polymer chain interaction among the particles. Particles with a small amount of relatively low-molecular-weight secondary polymer were dispersible in the methanol content range from 0 to 90 vol%. Polystyrene-modified particles never aggregated, even in 90 vol% methanol solution. An ESR study of the suspension in ethyl acetate-hexane cosolvent suggested that the dispersibility of these composite particles in ethyl acetate-rich solution is attributable to steric repulsion between solvated and expanded secondary polymer chains among the particles. The dispersibility of the composite particles in methanol-rich solution was controlled by a delicate balance between the electrostatic repulsion and the interparticle attraction due to the desolvated and insoluble polymer chain interaction among the particles. Copyright 1999 Academic Press.

  2. Maleic anhydride

    Integrated Risk Information System (IRIS)

    Maleic anhydride ; CASRN 108 - 31 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  3. Phthalic anhydride

    Integrated Risk Information System (IRIS)

    Phthalic anhydride ; CASRN 85 - 44 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  4. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... maleic anhydride monomer content shall be determined by a gas chromatographic method titled “Determination of Residual Maleic Anhydride in Polymers by Gas Chromatography,” which is incorporated...

  5. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... maleic anhydride monomer content shall be determined by a gas chromatographic method titled “Determination of Residual Maleic Anhydride in Polymers by Gas Chromatography,” which is incorporated...

  6. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... maleic anhydride monomer content shall be determined by a gas chromatographic method titled “Determination of Residual Maleic Anhydride in Polymers by Gas Chromatography,” which is incorporated...

  7. Synthesis, characterisation, and evaluation of a cross-linked disulphide amide-anhydride-containing polymer based on cysteine for colonic drug delivery.

    PubMed

    Lim, Vuanghao; Peh, Kok Khiang; Sahudin, Shariza

    2013-12-18

    The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide)-3-mercapto propionic anhydride (trithiol monomers) using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5-1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.

  8. Rheological Analysis of Polymer Interactions and Ageing of Poly(Methylvinylether-Co-Maleic Anhydride)/Poly(Vinyl Alcohol) Binary Networks and Their Effects on Mucoadhesion.

    PubMed

    Andrews, Gavin P; Laverty, Thomas P; Jones, David S

    2015-12-01

    Polymer blends of poly(vinylalcohol, PVA) and poly(methylvinylether-co-maleic anhydride, PMVE/MA) were formulated and their viscoelastic and mucoadhesive properties characterised. The viscoelastic and mucoadhesive properties were dependent on polymer concentration, molecular weight of PVA and PVA:PMVE/MA ratio. Alteration of these properties allowed platforms to be designed to offer defined rheological and mucoadhesive properties, properties that could not be achieved using monopolymeric platforms. A strong correlation was noted between the modulus of the polymeric blends and mucoadhesion. After storage, the polymeric blends underwent rheological structuring (ageing) with an attendant enhancement of mucoadhesion. In certain blends containing the highest molecular weight of PVA (146-186 kDa), storage ultimately resulted in an increase and then a significant decrease in the rheological and mucoadhesive properties, the latter phenomenon being accredited to polymer recrystallisation. Ageing of the rheological and mucoadhesive properties was modelled using an exponential growth model, allowing predictions of the storage period associated with the maxima in viscoelastic and mucoadhesive properties. These observations highlight the possible implications whenever interactive polymeric blends are employed in drug delivery. Caution is therefore urged whenever a formulation strategy based on interactive polymer blends is employed to ensure that ageing is fully understood and mathematically characterised.

  9. Carbon-13 cross-polarization magic-angle-spinning nuclear magnetic resonance investigation of the interactions between maleic anhydride grafted polypropylene and wood polymers.

    PubMed

    Rude, Erica; Laborie, Marie-Pierre G

    2008-05-01

    The chemical interactions between maleic anhydride grafted polypropylene (MAPP) and wood were studied with solid-state carbon-13 cross-polarization magic-angle-spinning nuclear magnetic resonance ((13)C CPMAS NMR) spectroscopy. MAPP was synthesized with 100% (13)C enrichment at the C(1) and C(4) carbons to allow detection of the [1,4-(13)C(2)]MAPP functional groups and was melt blended with cellulose, lignin, and maple wood. In the cellulose/MAPP blend, changes in (13)C CPMAS NMR corrected signal intensities for the anhydride and dicarboxylic maleic acid functionalities suggested that esterification may have occurred predominantly from the more numerous diacid carbons. A single proton longitudinal relaxation in the rotating frame, (H)T(1rho), for the MAPP and the cellulose carbons in the blend suggested that they were spin coupled, i.e., homogeneous on a 10-200 Angstrom scale. Esterification was also suggested in the lignin/MAPP blend. Furthermore, the more significant changes in the intensities of the carbonyl signals and (H)T(1rho) values suggested that lignin may be more reactive to MAPP than cellulose. Finally, when maple was melt blended with MAPP, the same trends in the (13)C CP-MAS NMR spectra and (H)T(1rho) behavior were observed as when MAPP was blended with cellulose or lignin. This study therefore clarifies that during melt compounding of wood with MAPP, esterification occurs with wood polymers, preferentially with lignin. Understanding the interactions of MAPP with wood is of significance for the development of natural-fiber-reinforced thermoplastic composites.

  10. Phenylethynyl Phthalic Anhydride

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Controlled molecular weight PhenylEthynyl Terminated Imide oligomers (PETIs) have been prepared by the cyclodehydration of precursor phenylethynyl terminated amic acid oligomers. Amino terminated amic acid oligomers are prepared from the reaction of dianhydride(s) with an excess of diamine(s) and subsequently endcapped with PhenylEthynyl Phthalic Anhydride(s) (PEPA). The polymerizations are carried out in polar aprotic solvents such as N-methyl-2pyrrolidinone or N N-dimethylacetamide under nitrogen at room temperature. The amic acid oligomers are subsequently cyclodehydrated either thermally or chemically to the corresponding imide oligomers. Direct preparation of PETIs from the reaction of dianhydride(s) with an excess of diamine(s) and endcapped with phenylethynyl phthalic anhydride(s) has been performed in m-cresol. Phenylethynyl phthalic anhydrides are synthesized by the palladium catalyzed reaction of phenylacetylene with bromo substituted phthalic anhydrides in triethylamine. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  11. Isomeric oxydiphthalic anhydride polyimides

    NASA Technical Reports Server (NTRS)

    Gerber, Margaret K.; Pratt, J. Richard; Stclair, Terry L.

    1988-01-01

    Much of the polyimide research at Langley Research Center has focused on isomeric modification of the diamine component; polyimides having considerably improved processability and adhesion have resulted. The present structure-property study was designed to investigate how isomeric attachment of the three oxydiphthalic anhydride (ODPA) polyimides affects their properties. Each dianhydride, 3,4,3',4'-oxydiphthalic anhydride (4,4'-OPDA,I), 2,3,2',3'-oxydiphthalic anhydride (3,3'-ODPA,II), and 2,3,3',4'-oxydiphthalic anhydride (3,4'-OPDA,III), was reacted with p-phenylenediamine, 4,4'-oxydianiline, 3,3'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, and 4,4'-bis(3-aminophenoxy)benzophenone in DMAc. The inherent viscosities of the resulting poly(amic acids) were determined. Thermally imidized films were studied for their creasability and solubility, as well as by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and wide angle X-ray scattering (WAXS). A comparison of these properties will be made.

  12. Succinic anhydrides from epoxides

    DOEpatents

    Coates, Geoffrey W.; Rowley, John M.

    2013-07-09

    Catalysts and methods for the double carbonylation of epoxides are disclosed. Each epoxide molecule reacts with two molecules of carbon monoxide to produce a succinic anhydride. The reaction is facilitated by catalysts combining a Lewis acidic species with a transition metal carbonyl complex. The double carbonylation is achieved in single process by using reaction conditions under which both carbonylation reactions occur without the necessity of isolating or purifying the product of the first carbonylation.

  13. Maleic anhydride from normal butane

    SciTech Connect

    Cooley, S.D.; Doshi, B.

    1987-01-01

    Worldwide about one billion pounds of maleic anhydride is used annually in the manufacture of a number of commercially valuable products, including unsaturated polyester resins, agricultural chemicals, and lubricating oil additives. Maleic anhydride is not found in nature. It was first prepared in 1834 by heating malic acid (hydroxy-succinic acid, a compound found in apples and many other fruits). Maleic anhydride was not available commercially until ca. 1930 when the catalytic air oxidation of benzene was begun by National Aniline and Chemical on an industrial scale. The estimated worldwide production in 1985 was 1023 million pounds coming from more than 35 plants varying in capacity from 6 million pounds to 170 million pounds annually.

  14. Poly(butylene succinate-co-butylene adipate)/cellulose nanocrystal composites modified with phthalic anhydride.

    PubMed

    Zhang, Xuzhen; Zhang, Yong

    2015-12-10

    As a kind of biomass nanofiller for polymers, cellulose nanocrystal (CNC) has good mechanical properties and reinforcing capability. To improve the compatibility of poly(butylene succinate-co-butylene adipate) (PBSA)/CNC composites, phthalic anhydride was used as a compatilizer during melt mixing, leading to the significant improvement of the mechanical properties and thermal stability of the composites, which is related to the better dispersion of CNC in the composites. The addition of phthalic anhydride could accelerate the crystallization of PBSA component as evidenced by the curves of isothermal crystallization of the composites, but had little effect on the crystalline polymorphs of PBSA component. The addition of phthalic anhydride could strongly improve the hydrophobicity of the composites. The good mechanical properties, fast crystallization and improved hydrophobicity of PBSA/CNC composites with phthalic anhydride are favor to their practical commercial utilization.

  15. Salicylic acid (SA) bioaccessibility from SA-based poly(anhydride-ester).

    PubMed

    Rogers, Michael A; Yan, Yim-Fan; Ben-Elazar, Karen; Lan, Yaqi; Faig, Jonathan; Smith, Kervin; Uhrich, Kathryn E

    2014-09-08

    The bioaccessibility of salicylic acid (SA) can be effectively modified by incorporating the pharmacological compound directly into polymers such as poly(anhydride-esters). After simulated digestion conditions, the bioaccessibility of SA was observed to be statistically different (p < 0.0001) in each sample: 55.5 ± 2.0% for free SA, 31.2 ± 2.4% the SA-diglycolic acid polymer precursor (SADG), and 21.2 ± 3.1% for SADG-P (polymer). The release rates followed a zero-order release rate that was dependent on several factors, including (1) solubilization rate, (2) macroscopic erosion of the powdered polymer, (3) hydrolytic cleavage of the anhydride bonds, and (4) subsequent hydrolysis of the polymer precursor (SADG) to SA and diglycolic acid.

  16. Surface modification of cell culture carriers: routes to anhydride functionalization of polystyrene.

    PubMed

    Nitschke, Mirko; Ricciardi, Serena; Gramm, Stefan; Zschoche, Stefan; Herklotz, Manuela; Rivolo, Paola; Werner, Carsten

    2012-02-01

    Physico-chemical and topographical cues allow to control the behavior of adherent cells. Towards this goal, commercially available cell culture carriers can be finished with a laterally microstructured biomolecular functionalization. As shown in a previous study [Biomacromolecules 4 (2003) 1072], the anhydride moiety facilitates a simple and versatile way to protein binding. The present work addresses the technical issue of anhydride surface functionalization of polystyrene, the most common material for cell culture ware. Different approaches based on low pressure plasma, electron beam and ultraviolet light techniques (i.e. maleic anhydride plasma reactions; plasma, electron beam and UV immobilization of functional polymer thin films; grafting of functional polymers to plasma activated surfaces) are introduced and briefly illustrated with examples. Results are characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and ellipsometry. The different routes are compared in terms of technical feasibility and achievable surface properties.

  17. Thermoplastic adhesives based on 4,4'-isophthaloyldiphthalic anhydride (IDPA)

    NASA Technical Reports Server (NTRS)

    Progar, Donald J.; Stclair, Terry L.; Pratt, J. Richard

    1988-01-01

    Thermoplastic polyimides were prepared and evaluated as adhesives. These materials are based on 4,4'-isophthaloyldiphathalic anhydride (IDAP) and either metaphenylene diamine (MPD) or 3,3'-diaminobenzophenone (DBAP). Both polymers exhibit excellent adhesive properties; however, the IDPA-MPD is the more attractive system because of a combination of high mechanical and physical properties as well as being made from commercially attractive monomers. The IDPA-MPD is an isomeric form of the commercially available adhesive and matrix resin, LARC-TPI and both systems have the same glass transition temperature and exhibit similar adhesive properties.

  18. A preliminary study on the dynamic-mechanical behaviour of compression moulded polypropylene/carbon fiber composites interfacially modified by a succinic anhydride grafted atactic polypropylene from polymer wastes

    NASA Astrophysics Data System (ADS)

    García-Martínez, Jesús María; Areso, Susana; Collar, Emilia P.

    2016-05-01

    Present communication is devoted to the study of the effect of a novel interfacial agent in polypropylene/carbon fibre composites. The interfacial agent used is a succinic anhydride grafted atactic polypropylene containing both succinic bridges and side grafts (aPP-SASA) and with 5.6% (5.6.10-4g/mol) of grafting content obtained at the GIP labs. The study considers the study dynamic-mechanical behaviour with temperature at a frequency of 1 hz to ascertain the differences in the interfacial activity. The samples were compression molded in order to isolate as far as possible the effect of the solely aPP-SASA in absence of those synergetic effects due to the preferential orientation of the fibres.

  19. Phenolic acid-based poly(anhydride-esters) as antioxidant biomaterialsa

    PubMed Central

    Prudencio, Almudena; Faig, Jonathan J.; Song, MinJung

    2015-01-01

    Poly(anhydride-esters) comprised of naturally occurring, non-toxic phenolic acids, namely syringic and vanillic acid, with antioxidant properties were prepared via solution polymerization methods. Polymer and polymer precursor physiochemical properties were characterized, including polymer molecular weight and thermal properties. In vitro release studies illustrated that polymer hydrolytic degradation was influenced by relative hydrophobicity and degree of methoxy substitution of the phenolic acids. Further, the released phenolic acids were found to maintain antioxidant potency relative to free phenolic acid controls as determined by a 2,2-diphenyl-1-picrylhydrazyl assay. Polymer cytotoxicity was assessed with L929 fibroblasts in polymer-containing media; appropriate cell morphology and high fibroblast proliferation were obtained for the polymers at the lower concentrations. These polymers deliver non-cytotoxic levels of naturally occurring antioxidants, which could be efficacious in topical delivery of antioxidant therapies. PMID:26425923

  20. Collagen functionalized with unsaturated cyclic anhydrides-interactions in solution and solid state.

    PubMed

    Potorac, S; Popa, M; Picton, L; Dulong, V; Verestiuc, L; Le Cerf, D

    2014-03-01

    Maleic anhydride (CMA) and itaconic anhydride modified collagen (CITA) were prepared as precursors for production of interpenetrated polymer networks (IPN). Calculated values for Huggins coefficient in aqueous diluted and semi-diluted solutions of modified collagen indicated a slightly tendency of aggregation for itaconic anhydride-modified collagen. In semi-diluted solution collagen (Coll) and CMA present slightly differences in the thixotropic behavior, while CITA has a pronounced thixotropic behavior. Flow and oscillatory measurements revealed an elastic behavior of the collagen solutions, pure and modified with MA or ITA, as the storage modulus (G') has always a superior value compared with the loss modulus (G″). The denaturation temperature (Td) of unmodified collagen increased from 34°C to 40°C for CMA and to 39°C for CITA respectively, by formation of covalent bonds that stabilize the triple helix.

  1. Langmuir and Langmuir-Blodgett films of a maleic anhydride derivative: effect of subphase divalent cations.

    PubMed

    Martín-García, B; Velázquez, M Mercedes; Pérez-Hernández, J A; Hernández-Toro, J

    2010-09-21

    We report the study of the equilibrium and dynamic properties of Langmuir monolayers of poly(styrene-co-maleic anhydride) partial 2-buthoxyethyl ester cumene terminated polymer and the effect of the Mg(NO(3))(2) addition in the water subphase on the film properties. Results show that the polymer monolayer becomes more expanded when the electrolyte concentration in the subphase increases. Dense polymer films aggregate at the interface. The aggregates are transferred onto silicon wafers using the Langmuir-Blodgett methodology and the morphology is observed by AFM. The structure of aggregates depends on the subphase composition of the Langmuir film transferred onto the silicon wafer.

  2. A new approach to reducing the flammability of layered double hydroxide (LDH)-based polymer composites: preparation and characterization of dye structure-intercalated LDH and its effect on the flammability of polypropylene-grafted maleic anhydride/d-LDH composites.

    PubMed

    Kang, Nian-Jun; Wang, De-Yi; Kutlu, Burak; Zhao, Peng-Cheng; Leuteritz, Andreas; Wagenknecht, Udo; Heinrich, Gert

    2013-09-25

    Dye structure-intercalated layered double hydroxide (d-LDH) was synthesized using a one-step method, and its intercalated behaviors have been characterized by Fourier transform infrared spectroscopy (FTIR), wide angle X-ray scattering (WAXS), scanning electron microscopy, thermogravimetric analysis (TGA), etc. As a novel functional potential fire-retarding nanofiller, it was used to prepare a polypropylene-grafted maleic anhydride (PP-g-MA)/d-LDH composite by refluxing the mixture of d-LDH and PP-g-MA in xylene, aiming to investigate its effect on the flammability of the PP-g-MA composite. The morphological properties, thermal stability, and flame retardant properties of the PP-g-MA/d-LDH composite were determined by FTIR, WAXS, transmission electron microscopy, TGA, and microscale combustion calorimetry. Compared with NO3-LDH (unmodified LDH) and LDH intercalated by sodium dodecylbenzenesulfonate (conventional organo-modified LDH), d-LDH can significantly decrease the heat release rate and the total heat release of the PP-g-MA composite, offering a new approach to imparting low flammability to LDH-based polymer composites.

  3. Synthesis of Hydroxy-Terminated Dinitropropyl Acrylate Polymers and Improved Characterization of Hydroxy-Terminated Prepolymers

    DTIC Science & Technology

    1983-03-01

    azelate polyesterdiol from Wittco PA Phthalic anhydride PCP Polycaprolactone diol from Union Carbide PDNPA Polydinitropropyl acrylate (our experimental... anhydride (AA) in the presence of N-methylimidazole (NMIM) (15)reported by Conners , and (b) phthalic anhydride (PA) in the presence of pyridine (PY...three meq sample of dried polymer was weighed into a 100 ml round bottom flask and 50 ml of phthalic anhydride stock solution (0.6 N) in anhydrous

  4. Evidence of glass transition in thin films of maleic anhydride derivatives: Effect of the surfactant coadsorption

    NASA Astrophysics Data System (ADS)

    López-Dıaz, D.; Velázquez, M. M.

    2008-08-01

    The glass transition temperature of poly (maleic anhydride-alt-1-octadecen) and poly (styrene-co-maleic anhydride) cumene-terminated thin films has been measured by mechanical relaxation of Langmuir films of these polymers. The dynamical properties show glass-like features (non-Arrhenius relaxation times and non-Debye mechanical response) interpreted by the coupling model. The glass transition temperature values determined by a mechanical relaxation experiment (step-compression) agree very well with those obtained by surface potential measurements. It is found that the glass transition temperature values in thin films decrease by about 100K as compared with those corresponding to the bulk polymers. The coadsorption of the water-insoluble surfactant DODAB decreases the glass transition temperature.

  5. Biomaterial properties evaluation of poly(vinyl acetate- alt-maleic anhydride)/chitosan nanocapsules

    NASA Astrophysics Data System (ADS)

    Raţă, Delia Mihaela; Popa, Marcel; Chailan, Jean-François; Zamfir, Carmen Lăcrămioara; Peptu, Cătălina Anişoara

    2014-08-01

    Nanocapsules with diameter around 100 nm based on a natural polymer (chitosan) and a synthetic polymer poly(vinyl acetate- alt-maleic anhydride) [poly(MAVA)] by interfacial condensation method were prepared. The present study proposes a new type of biocompatible nanocapsules based on poly(vinyl acetate- alt-maleic anhydride-chitosan) (MCS) able to become a reliable support for inclusion and release of drugs. The spherical shape of the nanocapsules was evidenced by scanning electron microscopy. Nanocapsules presented a good Norfloxacin loading and release capacity. Haemocompatibility tests have demonstrated that the nanocapsules present a low toxicity and a good compatibility with sanguine medium. The biocompatibility properties of the nanocapsules after their intraperitoneal administration in rats were evidenced by histopathological examination of different organs (brain, liver, kidney, and lung). The results are encouraging and the nanocapsules can be used as controlled drug delivery systems.

  6. Preparation of hydrophilic styrene maleic anhydride copolymer fibers for use in papermaking

    DOEpatents

    Rave, Terence W.

    1979-01-01

    Hydrophilic fibers may be prepared by discharging a heated and pressurized dispersion of a styrene-maleic anhydride copolymer into a zone of reduced temperature and pressure, and then modifying the fibers so produced by treatment with an aqueous admixture of selected cationic and anionic water-soluble, nitrogen-containing polymers. Blends of the hydrophilic fibers with wood pulp provide paper products having improved physical properties.

  7. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Styrene-maleic anhydride copolymers. 177.1820... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1820 Styrene-maleic anhydride copolymers. Styrene-maleic anhydride copolymers identified in paragraph (a) of this section may be...

  8. Improved zein articles using polyethylenemaleic anhydride

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Developing corn protein (zein) articles with improved physical properties and solvent resistance will have a beneficial impact on companies that use corn. The effect of using the crosslinking reagent polyethylenemaleic anhydride (PEMA) on the properties and solubility of zein articles were studied. ...

  9. Ring-opening copolymerization of maleic anhydride with epoxides: a chain-growth approach to unsaturated polyesters.

    PubMed

    DiCiccio, Angela M; Coates, Geoffrey W

    2011-07-20

    We report the ring-opening copolymerization of maleic anhydride with a variety of epoxides catalyzed by a chromium(III) salen complex. Quantitative isomerization of the cis-maleate form of all polymers affords the trans-fumarate analogues. Addition of chain transfer reagents yields low M(n), narrow PDI polymer samples. This method provides access to a range of new unsaturated polyesters with versatile functionality, as well as the first synthesis of high molecular weight poly(propylene fumarate).

  10. Preparation of poly(glycidylmethacrylate-divinylbenzene) weak acid cation exchange stationary phases with succinic anhydride, phthalic anhydride, and maleic anhydride for ion chromatography.

    PubMed

    Liu, Junwei; Wang, Yong; Wu, Shuchao; Zhang, Peimin; Zhu, Yan

    2016-08-01

    In this work, poly(glycidylmethacrylate-divinylbenzene) microspheres were prepared and applied for the preparation of weak acid cation exchange stationary phases. Succinic anhydride, phthalic anhydride, and maleic anhydride were selected as carboxylation reagents to prepare three weak acid cation exchangers by direct chemical derivatization reaction without solvent or catalyst. The diameters and dispersity of the microspheres were characterized by scanning electron microscopy; the amount of accessible epoxy groups and mechanical stability were also measured. The weak acid cation exchangers were characterized by Fourier transform infrared spectroscopy; the content of carboxyl groups was measured by traditional acid base titration method. The chromatographic properties were characterized and compared by separating alkali, alkaline earth metal ions and ammonium and polar amines. The separation properties enhanced in the order of succinic anhydride, phthalic anhydride, and maleic anhydride modified poly(glycidylmethacrylate-divinylbenzene) cation exchangers.

  11. Poly(anhydride-esters) Comprised Exclusively of Naturally Occurring Antimicrobials and EDTA: Antioxidant and Antibacterial Activities

    PubMed Central

    2015-01-01

    Carvacrol, thymol, and eugenol are naturally occurring phenolic compounds known to possess antimicrobial activity against a range of bacteria, as well as antioxidant activity. Biodegradable poly(anhydride-esters) composed of an ethylenediaminetetraacetic acid (EDTA) backbone and antimicrobial pendant groups (i.e., carvacrol, thymol, or eugenol) were synthesized via solution polymerization. The resulting polymers were characterized to confirm their chemical composition and understand their thermal properties and molecular weight. In vitro release studies demonstrated that polymer hydrolytic degradation was complete after 16 days, resulting in the release of free antimicrobials and EDTA. Antioxidant and antibacterial assays determined that polymer release media exhibited bioactivity similar to that of free compound, demonstrating that polymer incorporation and subsequent release had no effect on activity. These polymers completely degrade into components that are biologically relevant and have the capability to promote preservation of consumer products in the food and personal care industries via antimicrobial and antioxidant pathways. PMID:24702678

  12. Poly(anhydride-esters) comprised exclusively of naturally occurring antimicrobials and EDTA: antioxidant and antibacterial activities.

    PubMed

    Carbone-Howell, Ashley L; Stebbins, Nicholas D; Uhrich, Kathryn E

    2014-05-12

    Carvacrol, thymol, and eugenol are naturally occurring phenolic compounds known to possess antimicrobial activity against a range of bacteria, as well as antioxidant activity. Biodegradable poly(anhydride-esters) composed of an ethylenediaminetetraacetic acid (EDTA) backbone and antimicrobial pendant groups (i.e., carvacrol, thymol, or eugenol) were synthesized via solution polymerization. The resulting polymers were characterized to confirm their chemical composition and understand their thermal properties and molecular weight. In vitro release studies demonstrated that polymer hydrolytic degradation was complete after 16 days, resulting in the release of free antimicrobials and EDTA. Antioxidant and antibacterial assays determined that polymer release media exhibited bioactivity similar to that of free compound, demonstrating that polymer incorporation and subsequent release had no effect on activity. These polymers completely degrade into components that are biologically relevant and have the capability to promote preservation of consumer products in the food and personal care industries via antimicrobial and antioxidant pathways.

  13. Dicarboxylic acid anhydride condensation with compounds containing active methylene groups. 4: Some 4-nitrophthalic anhydride condensation reactions

    NASA Technical Reports Server (NTRS)

    Oskaja, V.; Rotberg, J.

    1985-01-01

    By 4-nitrophthalic anhydride condensation with acetoacetate in acetic anhydride and triethylamine solution with subsequent breakdown of the intermediate condensation product, 5-nitroindanedione-1,3 was obtained. A 4-nitrophthalic anhydride with acetic anhydride, according to reaction conditions, may yield two products: in the presence of potassium acetate and at high temperatures 4-(or 5-)-nitro-2-acetylbenzoic acid is formed: in the presence of triethylamine and at room temperature 5-( or 6-)-nitrophthalic acetic acid is isolated. A 4-nitrophthalic anhydride and malonic acid in pyridine solution according to temperature yield either 5-( or 6-)-nitrophthalic acetic acid or 4-(or 5-)-nitro-2-acetylbenzoic acid.

  14. Design and Synthesis of Fast-Degrading Poly(anhydride-esters)

    PubMed Central

    Carbone, Ashley L.

    2009-01-01

    Fast-degrading, salicylate-based poly(anhydride-esters) were designed to degrade and release the active component, salicylic acid (SA), within 1 week. The polymer degradation was enhanced by using shorter or oxygen-containing aliphatic chains. A copolymer of diglycolic acid was also made with a salicylate-based diacid for comparison of polymer properties, including SA release. Both methods resulted in polyanhydrides with molecular weights ranging from 14 500 to 27 800 Da and displayed glass transition temperatures near physiological conditions, namely 33–40°C. the homo- and copolymers completely degraded within one week releasing the chemically incorporated SA. PMID:20161638

  15. Condensation of anhydrides or dicarboxylic acids with compounds containing active methylene groups. Part 19: Condensation of phthalic and substituted phthalic anhydrides with benzoylacetic ester

    NASA Technical Reports Server (NTRS)

    Rotberg, Y. T.; Oshkaya, V. P.

    1985-01-01

    Phthalylbenzoylacetic ester and its nitro and halogen derivatives were prepared through condensation of phthalic anhydride, nitrophthalic anhydride, and phthalic halide anhydride with benzoylacetic ester in a solution of acetic anhydride and triethylamine. The condensation of hemipinic acid anhydride proceeds similarly, but under more drastic conditions. Derivatives of indan-1,3-dione are also formed, with a small yield, in the reaction of nitrophthalic anhydrides with benzoylacetic ester in the presence of increased quantities of triethylamine.

  16. Chemicals from coal - The Eastman experience. [Anhydride

    SciTech Connect

    Larkins, T.H.

    1986-03-01

    Tennessee Eastman Company is a major producer of chemicals, fibers and plastics. It is located in Kingsport, Tennessee, headquarters for the Eastman Chemicals Division of Eastman Kodak Company. Eastman Companies employ a total of 12,250 people in Kingsport. Other domestic Eastman Chemicals Division plants are located in Texas, South Carolina, Arkansas and New York. The authors began to witness a flow of products from one of the most highly technical and sophisticated chemical processes in operation in the world. The Eastman ''Chemicals-from-Coal'' facility is not a sunfuel plant. To be sure, we are producing syngas from coal, but the syngas is used to produce acetic anhydride. Acetic anhydride is very important to Eastman. This chemical intermediate eventually finds its way into such diverse products as aspirin, cigarette filters, tool handles, and photographic film. It also is used to make other chemical intermediates such as cellulose esters, anhydrides, triacetin, and acetate ester solvents, all of which have a variety of end uses. The chemicals-from-coal project had its inception in the late 1960's when Eastman stepped up its program of energy conservation and began a search for lower cost chemical feedstocks. Our concern started before the national concern caused by a ten-fold increase in petroleum prices during the past decade.

  17. Stability of a salicylate-based poly(anhydride-ester) to electron beam and gamma radiation

    PubMed Central

    Rosario-Meléndez, Roselin; Lavelle, Linda; Bodnar, Stanko; Halperin, Frederick; Harper, Ike; Griffin, Jeremy; Uhrich, Kathryn E.

    2011-01-01

    The effect of electron beam and gamma radiation on the physicochemical properties of a salicylate-based poly(anhydride-ester) was studied by exposing polymers to 0 (control), 25 and 50 kGy. After radiation exposure, salicylic acid release in vitro was monitored to assess any changes in drug release profiles. Molecular weight, glass transition temperature and decomposition temperature were evaluated for polymer chain scission and/or crosslinking as well as changes in thermal properties. Proton nuclear magnetic resonance and infrared spectroscopies were also used to determine polymer degradation and/or chain scission. In vitro cell studies were performed to identify cytocompatibility following radiation exposure. These studies demonstrate that the physicochemical properties of the polymer are not substantially affected by exposure to electron beam and gamma radiation. PMID:21909173

  18. 78 FR 4792 - Epoxy Polymer; Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-23

    ... AGENCY 40 CFR Part 180 Epoxy Polymer; Exemption From the Requirement of a Tolerance AGENCY: Environmental... requirement of a tolerance for residues of polymers of one or more diglycidyl ethers of bisphenol A...- cyclohexane-dicarboxylic anhydride and 1,2,3,6-tetrahydrophthalic anhydride; also referred to as epoxy...

  19. Polymers.

    ERIC Educational Resources Information Center

    Tucker, David C.

    1986-01-01

    Presents an open-ended experiment which has students exploring polymer chemistry and reverse osmosis. This activity involves construction of a polymer membrane, use of it in a simple osmosis experiment, and application of its principles in solving a science-technology-society problem. (ML)

  20. Optimize energy usage in phthalic anhydride units

    SciTech Connect

    de Virgiliis, A.; Gerunda, A.

    1982-05-01

    By maximizing the air to o-xylene ratios, Ftalital has developed a phthalic anhydride (PA) unit completely energy self-sufficient, generating its own electric power without affecting export steam. In the improved version of the production schemes a single-train synthesis reactors with 15,500 tubes each are used. These reactors have a production capacity of 35,000 metric tpy each and have operated with catalyst developed for high o-xylene-to-air ratios. Economic considerations are included.

  1. Alternating copolymerization of propylene oxide with biorenewable terpene-based cyclic anhydrides: a sustainable route to aliphatic polyesters with high glass transition temperatures.

    PubMed

    Van Zee, Nathan J; Coates, Geoffrey W

    2015-02-23

    The alternating copolymerization of propylene oxide with terpene-based cyclic anhydrides catalyzed by chromium, cobalt, and aluminum salen complexes is reported. The use of the Diels-Alder adduct of α-terpinene and maleic anhydride as the cyclic anhydride comonomer results in amorphous polyesters that exhibit glass transition temperatures (Tg ) of up to 109 °C. The polymerization conditions and choice of catalyst have a dramatic impact on the molecular weight distribution, the relative stereochemistry of the diester units along the polymer chain, and ultimately the Tg of the resulting polymer. The aluminum salen complex exhibits exceptional selectivity for copolymerization without transesterification or epimerization side reactions. The resulting polyesters are highly alternating and have high molecular weights and narrow polydispersities.

  2. Preparation of .alpha., .beta.-unsaturated carboxylic acids and anhydrides

    DOEpatents

    Spivey, James Jerry; Gogate, Makarand Ratnakav; Zoeller, Joseph Robert; Tustin, Gerald Charles

    1998-01-01

    Disclosed is a process for the preparation of .alpha.,.beta.-unsaturated carboxylic acids and anhydrides thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic anhydride in the presence of a catalyst comprising mixed oxides of vanadium, phosphorus and, optionally, a third component selected from titanium, aluminum or, preferably silicon.

  3. Preparation of {alpha}, {beta}-unsaturated carboxylic acids and anhydrides

    DOEpatents

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Tustin, G.C.

    1998-01-20

    Disclosed is a process for the preparation of {alpha},{beta}-unsaturated carboxylic acids and anhydrides thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic anhydride in the presence of a catalyst comprising mixed oxides of vanadium, phosphorus and, optionally, a third component selected from titanium, aluminum or, preferably silicon.

  4. Biodegradable Ferulic Acid-containing Poly(anhydride-ester): Degradation Products with Controlled Release and Sustained Antioxidant Activity

    PubMed Central

    Ouimet, Michelle A.; Griffin, Jeremy; Carbone-Howell, Ashley L.; Wu, Wen-Hsuan; Stebbins, Nicholas D.; Di, Rong; Uhrich, Kathryn E.

    2013-01-01

    Ferulic acid (FA) is an antioxidant and photoprotective agent used in biomedical and cosmetic formulations to prevent skin cancer and senescence. Although FA exhibits numerous health benefits, physicochemical instability leading to decomposition hinders its efficacy. To minimize inherent decomposition, a FA-containing biodegradable polymer was prepared via solution polymerization to chemically incorporate FA into a poly(anhydride-ester). The polymer was characterized using nuclear magnetic resonance and infrared spectroscopies. The molecular weight and thermal properties were also determined. In vitro studies demonstrated that the polymer was hydrolytically degradable, thus providing controlled release of the chemically incorporated bioactive with no detectable decomposition. The polymer degradation products were found to exhibit antioxidant and antibacterial activity comparable to free FA and in vitro cell viability studies demonstrated that the polymer is non-cytotoxic towards fibroblasts. This renders the polymer a potential candidate for use as a controlled release system for skin care formulations. PMID:23327626

  5. Biodegradable ferulic acid-containing poly(anhydride-ester): degradation products with controlled release and sustained antioxidant activity.

    PubMed

    Ouimet, Michelle A; Griffin, Jeremy; Carbone-Howell, Ashley L; Wu, Wen-Hsuan; Stebbins, Nicholas D; Di, Rong; Uhrich, Kathryn E

    2013-03-11

    Ferulic acid (FA) is an antioxidant and photoprotective agent used in biomedical and cosmetic formulations to prevent skin cancer and senescence. Although FA exhibits numerous health benefits, physicochemical instability leading to decomposition hinders its efficacy. To minimize inherent decomposition, a FA-containing biodegradable polymer was prepared via solution polymerization to chemically incorporate FA into a poly(anhydride-ester). The polymer was characterized using nuclear magnetic resonance and infrared spectroscopies. The molecular weight and thermal properties were also determined. In vitro studies demonstrated that the polymer was hydrolytically degradable, thus providing controlled release of the chemically incorporated bioactive with no detectable decomposition. The polymer degradation products were found to exhibit antioxidant and antibacterial activity comparable to that of free FA, and in vitro cell viability studies demonstrated that the polymer is noncytotoxic toward fibroblasts. This renders the polymer a potential candidate for use as a controlled release system for skin care formulations.

  6. Biocompatibility of polysebacic anhydride microparticles with chondrocytes in engineered cartilage

    PubMed Central

    Ponnurangam, Sathish; O'Connell, Grace D.; Hung, Clark T.; Somasundaran, Ponisseril

    2015-01-01

    One of main challenges in developing clinically relevant engineered cartilage is overcoming limited nutrient diffusion due to progressive elaboration of extracellular matrix at the periphery of the construct. Macro-channels have been used to decrease the nutrient path-length; however, the channels become occluded with matrix within weeks in culture, reducing nutrient diffusion. Alternatively, microparticles can be imbedded throughout the scaffold to provide localized nutrient delivery. In this study, we evaluated biocompatibility of polysebacic anhydride (PSA) polymers and the effectiveness of PSA-based microparticles for short-term delivery of nutrients in engineered cartilage. PSA-based microparticles were biocompatible with juvenile bovine chondrocytes for concentrations up to 2mg/mL; however, cytotoxicity was observed at 20mg/mL. Cytotoxicity at high concentrations is likely due to intracellular accumulation of PSA degradation products and resulting lipotoxicity. Cytotoxicity of PSA was partially reversed in the presence of bovine serum albumin. In conclusion, the findings from this study demonstrate concentration-dependent biocompatibility of PSA-based microparticles and potential application as a nutrient delivery vehicle that can be imbedded in scaffolds for tissue engineering. PMID:26398146

  7. Characterization and in vitro degradation of salicylate-derived poly(anhydride-ester microspheres).

    PubMed

    Yeagy, Brian A; Prudencio, Almudena; Schmeltzer, Robert C; Uhrich, Kathryn E; Cook, Thomas J

    2006-09-01

    The aim of this study was to investigate how glass transition temperature (Tg) influenced polymer microsphere formation and degradation of three chemically, similar novel salicylatebased poly(anhydride-esters): poly[1,6-bis(o-carboxyphenoxy)hexanoate] (CPH), Tg = 59 degrees C; poly[1,8-bis(o-carboxyphenoxy)octanoate] (CPO), Tg = 30 degrees C; and poly[1,10-bis(ocarboxyphenoxy) decanoate] (CPD), Tg = 27 degrees C. Microspheres of these polymers were prepared using a modified oil-in-water solvent evaporation method and processed by either resuspension or washed by centrifugation. The morphology of the microspheres determined by scanning electron microscopy (SEM) revealed that an extra washing step appears to increase aggregation as the Tg decreases; whereas only limited aggregation occurred in the polymer with the lowest Tg, CPD, in those not washed by centrifugation. Residual polyvinyl alcohol apparently affected the drug release rates from the microspheres by a stabilization process that produced an 8 h lag time and a 5% decrease in the amount of drug released over a 7 day period compared to microspheres washed free of PVA. These results demonstrate that salicylate-based poly(anhydride-esters) with sufficiently high Tgs, can be processed into microspheres that release salicylate over a time period amenable for drug delivery applications.

  8. Stereocomplexes of enantiomeric lactic acid and sebacic acid ester-anhydride triblock copolymers.

    PubMed

    Slivniak, Raia; Domb, Abraham J

    2002-01-01

    A systematic study on the synthesis, characterization, degradation, and drug release of d-, l-, and dl-poly(lactic acid) (PLA)-terminated poly(sebacic acid) (PSA) and their stereocomplexes is reported. PLA-terminated sebacic acid polymers were synthesized by melt condensation of the acetate anhydride derivatives of PLA oligomers and sebacic anhydride oligomers to yield ABA triblock copolymers of molecular weights between 3000 and 9000 that melt at temperatures between 35 and 80 degrees C. Pairs of the corresponding enantiomeric ABA copolymers composed of l-PLA-PSA-l-PLA and d-PLA-PSA-d-PLA were solvent mixed to form stereocomplexes. The formed stereocomplexes exhibited higher crystalline melting temperature than the enantiomeric polymers, which indicate stereocomplex formulation. The PLA terminals had a significant effect on the polymer degradation and drug release rate. PSA with up to 20% w/w of PLA terminals degraded and released the incorporated drug for more than 3 weeks as compared with 10 days for PSA homopolymer.

  9. Heterogeneous catalyst for the production of ethylidene diacetate from acetic anhydride

    DOEpatents

    Ramprasad, Dorai; Waller, Francis Joseph

    1998-01-01

    This invention relates to a process for producing ethylidene diacetate by the reaction of acetic anhydride, acetic acid, hydrogen and carbon monoxide at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that is stable to hydrogenation and comprises an insoluble polymer having pendant quaternized heteroatoms, some of which heteroatoms are ionically bonded to anionic Group VIII metal complexes, the remainder of the heteroatoms being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled without loss in activity.

  10. Heterogeneous catalyst for the production of ethylidene diacetate from acetic anhydride

    DOEpatents

    Ramprasad, D.; Waller, F.J.

    1998-06-16

    This invention relates to a process for producing ethylidene diacetate by the reaction of acetic anhydride, acetic acid, hydrogen and carbon monoxide at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that is stable to hydrogenation and comprises an insoluble polymer having pendant quaternized heteroatoms, some of which heteroatoms are ionically bonded to anionic Group VIII metal complexes, the remainder of the heteroatoms being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled without loss in activity.

  11. Biocompatible photocrosslinked poly(ester anhydride) based on functionalized poly(epsilon-caprolactone) prepolymer shows surface erosion controlled drug release in vitro and in vivo.

    PubMed

    Mönkäre, J; Hakala, R A; Vlasova, M A; Huotari, A; Kilpeläinen, M; Kiviniemi, A; Meretoja, V; Herzig, K H; Korhonen, H; Seppälä, J V; Järvinen, K

    2010-09-15

    Star-shaped poly(epsilon-caprolactone) oligomers functionalized with succinic anhydride were used as prepolymers to prepare photocrosslinked poly(ester anhydride) to evaluate their in vivo drug delivery functionality and biocompatibility. Thus, in this work, erosion, drug release and safety of the photocrosslinked poly(ester anhydride) were examined in vitro and in vivo. A small water-soluble drug, propranolol HCl (M(w) 296 g/mol, solubility 50 mg/ml), was used as the model drug in an evaluation of the erosion controlled release. Drug-free and drug-loaded (10-60% w/w) poly(ester anhydride) discoids eroded in vitro (pH 7.4 buffer, +37 degrees C) linearly within 24-48 h. A strong correlation between the polymer erosion and the linear drug release in vitro was observed, indicating that the release had been controlled by the erosion of the polymer. Similarly, in vivo studies (s.c. implantation of discoids in rats) indicated that surface erosion controlled drug release from the discoids (drug loading 40% w/w). Oligomers did not decrease cell viability in vitro and the implanted discoids (s.c., rats) did not evoke any cytokine activity in vivo. In summary, surface erosion controlled drug release and the safety of photocrosslinked poly(ester anhydride) were demonstrated in this study.

  12. Synthesis of Oxyarylene BBB Polymers.

    DTIC Science & Technology

    1975-06-01

    is only soluble in highly corrosive solvents. A series of BBB polymers has been synthesized by the reaction of 1,4,5,8- naphthalenetetracarboxylic...an increased number of rotational sites along the polymer backbone were soluble in m- cresol and exhibited glass transition temperatures in the 300... corrosive solvents. A series of BBB polymers has been synthesized by the reaction of 1,4,5,8-naphthalenetetracarboxylic acid anhydride with oxyarylene

  13. Antimocrobial Polymer

    DOEpatents

    McDonald, William F.; Huang, Zhi-Heng; Wright, Stacy C.

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  14. Antimicrobial Polymer

    DOEpatents

    McDonald, William F.; Wright, Stacy C.; Taylor, Andrew C.

    2004-09-28

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The polymeric composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from metals, metal alloys, metal salts, metal complexes and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one example embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl; and the metallic antimicrobial agent is selected from chelated silver ions, silver metal, chelated copper ions, copper metal, chelated zinc ions, zinc metal and mixtures thereof.

  15. Tunable drug release profiles from salicylate-based poly(anhydride-ester) matrices using small molecule admixtures

    PubMed Central

    Ouimet, Michelle A; Snyder, Sabrina S; Uhrich, Kathryn E

    2013-01-01

    Poly(anhydride-esters) with salicylic acid, a nonsteroidal anti-inflammatory drug, chemically incorporated into the polymer backbone provide high inherent drug loading. These poly(anhydride-esters) hydrolytically degrade to release salicylic acid over extended time periods (>30 days); however, an initial lag period of no salicylic acid release is observed. This lag period could be unfavorable in applications where immediate salicylic acid release is desired. Poly(anhydride-esters) with short (2 days) and long (11 days) lag periods were admixed with various small molecules as a means to shorten or eliminate the lag period. Salicylic acid, larger salicylic acid prodrugs, and 1:1 combinations of the two were physically admixed, each at 1%, 5%, and 10% (w/w). All admixtures resulted in immediate salicylic acid release and a decrease in glass transition temperatures compared to polymer alone. By varying the amounts of salicylic acid and salicylic acid prodrugs incorporated into the polymer matrix, immediate and constant salicylic acid release profiles over varied time periods were achieved. PMID:24078768

  16. Synthesis and Characterization of Poly(maleic Anhydride)s Cross-linked Polyimide Aerogels

    NASA Technical Reports Server (NTRS)

    Guo, Haiquan; Meador, Mary Ann B.

    2015-01-01

    With the development of technology for aerospace applications, new thermal insulation materials are required to be flexible and capable of surviving high heat flux. For instance, flexible insulation is needed for inflatable aerodynamic decelerators which are used to slow spacecraft for entry, descent and landing (EDL) operations. Polyimide aerogels have low density, high porosity, high surface area, and better mechanical properties than silica aerogels and can be made into flexible thin films, thus they are potential candidates for aerospace needs. The previously reported cross-linkers such as octa(aminophenyl)silsesquioxane (OAPS) and 1,3,5-triaminophenoxybenzene (TAB) are either expensive or not commercially available. Here, we report the synthesis of a series of polyimide aerogels cross-linked using various commercially available poly(maleic anhydride)s, as seen in Figure 1. The amine end capped polyimide oligomers were made with 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) and diamine combinations of dimethylbenzidine (DMBZ) and 4, 4-oxydianiline (ODA). The resulting aerogels have low density (0.12 gcm3 to 0.16 gcm3), high porosity (90) and high surface area (380-554 m2g). The effect of the different poly(maleic anhydride) cross-linkers and polyimide backbone structures on density, shrinkage, porosity, surface area, mechanical properties, moisture resistance and thermal properties will be discussed.

  17. Controlled delivery of paclitaxel from stent coatings using novel styrene maleic anhydride copolymer formulations.

    PubMed

    Richard, Robert; Schwarz, Marlene; Chan, Ken; Teigen, Nikolai; Boden, Mark

    2009-08-01

    The controlled release of paclitaxel (PTx) from stent coatings comprising an elastomeric polymer blended with a styrene maleic anhydride (SMA) copolymer is described. The coated stents were characterized for morphology by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and for drug release using high-performance liquid chromatography (HPLC). Differential scanning calorimetry (DSC) was used to measure the extent of interaction between the PTx and polymers in the formulation. Coronary stents were coated with blends of poly(b-styrene-b-isobutylene-b-styrene) (SIBS) and SMA containing 7% or 14% maleic anhydride (MA) by weight. SEM examination of the stents showed that the coating did not crack or delaminate either before or after stent expansion. Examination of the coating surface via AFM after elution of the drug indicated that PTx resides primarily in the SMA phase and provided information about the mechanism of PTx release. The addition of SMA altered the release profile of PTx from the base elastomer coatings. In addition, the presence of the SMA enabled tunable release of PTx from the elastomeric stent coatings, while preserving mechanical properties. Thermal analysis reveled no shift in the glass transition temperatures for any of the polymers at all drug loadings studied, indicating that the PTx is not miscible with any component of the polymer blend. An in vivo evaluation indicated that biocompatibility and vascular response results for SMA/SIBS-coated stents (without PTx) are similar to results for SIBS-only-coated and bare stainless steel control stents when implanted in the non-injured coronary arteries of common swine for 30 and 90 days.

  18. Metal phthalocyanine polymers

    NASA Technical Reports Server (NTRS)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1984-01-01

    Metal 4, 4', 4", 4"'=tetracarboxylic phthalocyanines (MPTC) are prepared by reaction of trimellitic anhydride, a salt or hydroxide of the desired metal (or the metal in powdered form), urea and a catalyst. A purer form of MPTC is prepared than heretofore. These tetracarboxylic acids are then polymerized by heat to sheet polymers which have superior heat and oxidation resistance. The metal is preferably a divalent metal having an atomic radius close to 1.35A.

  19. Poly(anhydride-ester) and poly(N-vinyl-2-pyrrolidone) blends: salicylic acid-releasing blends with hydrogel-like properties that reduce inflammation.

    PubMed

    Ouimet, Michelle A; Fogaça, Renata; Snyder, Sabrina S; Sathaye, Sameer; Catalani, Luiz H; Pochan, Darrin J; Uhrich, Kathryn E

    2015-03-01

    Polymers such as poly(N-vinyl-2-pyrrolidone) (PVP) have been used to prepare hydrogels for wound dressing applications but are not inherently bioactive. For enhanced healing, PVP was blended with salicylic acid-based poly(anhydride-esters) (SAPAE) and shown to exhibit hydrogel properties upon swelling. In vitro release studies demonstrated that the chemically incorporated drug (SA) was released from the polymer blends over 3-4 d in contrast to 3 h, and that blends of higher PVP content displayed greater swelling values and faster SA release. The polymer blends significantly the inflammatory cytokine, TNF-α, in vitro without negative effects.

  20. Interaction and release of catechin from anhydride maleic-grafted polypropylene films.

    PubMed

    López de Dicastillo, Carol; Castro-López, Maria Del Mar; Lasagabaster, Aurora; López-Vilariño, Jose M; González-Rodríguez, M Victoria

    2013-04-24

    In this paper, investigations were carried out on catechin-loaded maleic anhydride (MAH)-modified polypropylenes (PP). Two maleic-modified polypropylenes (PPMAH) with different maleic concentrations have been blended with PP and catechin to obtain composites of improved catechin retention with the aim of studying the possible interactions between these grafted polymers with antioxidants, and a secondary interest in developing an active antioxidant packaging. Composite physicochemical properties were measured by thermal analysis (thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and oxidation induction time (OIT)) and infrared spectroscopy studies. Catechin release profiles into food simulants were obtained by HPLC-PDA-QqQ, following European legislation. Antiradical activity of composites was analyzed by the ABTS and DPPH method. The formation of intermolecular hydrogen bonds between catechin and functionalized PP has been confirmed by Fourier transform infrared (FTIR) studies. Besides, a small fraction of ester bonds, formed as a result of a chemical reaction between a fraction of the hydrolyzed anhydride and the catechin hydroxyl groups, is not discarded. OIT results also showed an increase in antioxidant effectiveness caused by the presence of catechin- and maleic-modified PPMAH in the blend formulations. Incorporation of MAH-grafted PP increased substantially the retention rate of catechin, being dependent on the MAH content of the grafted polypropylene. The described interactions between catechin and maleic groups, together with changes in PP morphology in comparison with reference PP explained lower antioxidant release. Besides formulation, antioxidant release was dependent on the type of food, the temperature, and the time.

  1. Grafting of poly (lactic acid) with maleic anhydride using supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Khankrua, R.; Pivsa-Art, S.; Hiroyuki, H.; Suttiruengwong, S.

    2015-07-01

    The aim of this work was to modify poly lactic acid (PLA) via free radical grafting with maleic anhydride (MA) by using supercritical carbon dioxide (SCCO2). Benzoyl peroxide (BPO) was used as an initiator. The solubility of MA in SCCO2 was first determined to estimate the suitable grafting conditions and equilibrium. From the solubility study of MA in SCCO2, it was found that the solubility of MA in SCCO2 increased with the increasing pressure and dissolution time. PLA films were first prepared by compression molding. The ratio of MA to BPO was 2:1. The reaction temperature and pressure were 70°C and 100 bar respectively. The grafting reaction and the degree of grafting were characterized by nuclear magnetic resonance (NMR) spectroscopy and titration, respectively. Scanning electron microscope (SEM) technique and contact angle were used to confirm the changes in physical properties of PLA film grafted MA. NMR spectrum indicated that the grafting of MA onto PLA was successively achieved. Degree of grafting by using SCCO2 was as high as 0.98%. This provided rather high grafting degree compared with other processes. SEM pictures showed the rough surface structure on modified PLA film. In addition, contact angle results showed an improvement of the hydrophilicity by maleic anhydride grafting onto polymers.

  2. Method for epoxy foam production using a liquid anhydride

    DOEpatents

    Celina, Mathias [Albuquerque, NM

    2012-06-05

    An epoxy resin mixture with at least one epoxy resin of between approximately 50 wt % and 100 wt %, an anhydride cure agent of between approximately 0 wt % and approximately 50 wt %, a tert-butoxycarbonyl anhydride foaming agent of between proximately 0.1-20 wt %, a surfactant and an imidazole or similar catalyst of less than approximately 2 wt %, where the resin mixture is formed from at least one epoxy resin with a 1-10 wt % tert-butoxycarbonyl anhydride compound and an imidazole catalyst at a temperature sufficient to keep the resin in a suitable viscosity range, the resin mixture reacting to form a foaming resin which in the presence of an epoxy curative can then be cured at a temperature greater than 50.degree. C. to form an epoxy foam.

  3. Quick don-doff electrode pastes

    NASA Technical Reports Server (NTRS)

    Mosier, B.

    1969-01-01

    Evaluation of electrode pastes for use in electrocardiographs and electroencephalographs found that the one having the desired don-doff properties had to be water soluble or a water dispersible base. Poly /methyl vinyl ether/maleic anhydride/ or starch gels of the gum drop variety are two such bases.

  4. THE RATIO OF THE GLASS TEMPERATURE TO THE MELTING POINT IN POLYMERS.

    DTIC Science & Technology

    PLASTICS , MELTING POINT, TRANSITION TEMPERATURE, POLYETHYLENE PLASTICS , VINYL PLASTICS , BUTADIENES, FLUORINE COMPOUNDS, STYRENE PLASTICS , POLYMERS...NYLON, PHYSICAL PROPERTIES, MOLECULAR STRUCTURE, CARBONATES, ESTERS, ACRYLIC RESINS, PHENOLIC PLASTICS , ANHYDRIDES, CARBOXYLIC ACIDS, PHTHALATES, UNITED KINGDOM.

  5. β-Functionalization of carboxylic anhydrides with β-alkyl substituents through carbene organocatalysis.

    PubMed

    Jin, Zhichao; Chen, Shaojin; Wang, Yuhuang; Zheng, Pengcheng; Yang, Song; Chi, Yonggui Robin

    2014-12-01

    The first NHC-catalyzed functionalization of carboxylic anhydrides is described. In this reaction, the β carbon behaves as a nucleophilic carbon and undergoes asymmetric reactions with electrophiles. Anhydrides with challenging β-alkyl substituents work effectively.

  6. Formulation of salicylate-based poly(anhydride-ester) microspheres for short- and long-term salicylic acid delivery

    PubMed Central

    Rosario-Meléndez, Roselin; Ouimet, Michelle A.; Uhrich, Kathryn E.

    2013-01-01

    The formulation of salicylate-based poly(anhydride-ester) (PAE) microspheres was optimized by altering polymer concentration and homogenization speed to improve the overall morphology. The microspheres were prepared using three salicylate-based PAEs with different chemical compositions comprised of either a heteroatomic, linear aliphatic, or branched aliphatic moiety. These PAEs broadened the range of complete salicylic acid release to now include days, weeks and months. The molecular weight (Mw), polydispersity index (PDI) and glass transition temperature (Tg) of the formulated polymers were compared to the unformulated polymers. In general, the Mw and PDI exhibited decreased and increased values, respectively, after formulation, whereas the Tg changes did not follow a specific trend. Microsphere size and morphology were determined using scanning electron microscopy. These microspheres exhibited smooth surfaces, no aggregation, and size distributions ranging from 2-34 m in diameter. In vitro release studies of the chemically incorporated salicylic acid displayed widely tunable release profiles. PMID:23420391

  7. Preparation and Characterization of Octenyl Succinic Anhydride Modified Taro Starch Nanoparticles

    PubMed Central

    Jiang, Suisui; Dai, Lei; Qin, Yang; Xiong, Liu; Sun, Qingjie

    2016-01-01

    The polar surface and hydrophilicity of starch nanoparticles (SNPs) result in their poor dispersibility in nonpolar solvent and poor compatibility with hydrophobic polymers, which limited the application in hydrophobic system. To improve their hydrophobicity, SNPs prepared through self-assembly of short chain amylose debranched from cooked taro starch, were modified by octenyl succinic anhydride (OSA). Size via dynamic light scattering of OSA-SNPs increased compared with SNPs. Fourier transform infrared spectroscopy data indicated the OSA-SNPs had a new absorption peak at 1727 cm-1, which was the characteristic peak of carbonyl, indicating the formation of the ester bond. The dispersibility of the modified SNPs in the mixture of water with nonpolar solvent increased with increasing of degree of substitution (DS). OSA-SNPs appear to be a potential agent to stabilize the oil-water systems. PMID:26918568

  8. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, Dorai; Waller, Francis Joseph

    1999-01-01

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  9. Preparation and Characterization of Octenyl Succinic Anhydride Modified Taro Starch Nanoparticles.

    PubMed

    Jiang, Suisui; Dai, Lei; Qin, Yang; Xiong, Liu; Sun, Qingjie

    2016-01-01

    The polar surface and hydrophilicity of starch nanoparticles (SNPs) result in their poor dispersibility in nonpolar solvent and poor compatibility with hydrophobic polymers, which limited the application in hydrophobic system. To improve their hydrophobicity, SNPs prepared through self-assembly of short chain amylose debranched from cooked taro starch, were modified by octenyl succinic anhydride (OSA). Size via dynamic light scattering of OSA-SNPs increased compared with SNPs. Fourier transform infrared spectroscopy data indicated the OSA-SNPs had a new absorption peak at 1727 cm-1, which was the characteristic peak of carbonyl, indicating the formation of the ester bond. The dispersibility of the modified SNPs in the mixture of water with nonpolar solvent increased with increasing of degree of substitution (DS). OSA-SNPs appear to be a potential agent to stabilize the oil-water systems.

  10. Preparation of extruded polyethylene/chitosan blends compatibilized with polyethylene-graft-maleic anhydride.

    PubMed

    Quiroz-Castillo, J M; Rodríguez-Félix, D E; Grijalva-Monteverde, H; Del Castillo-Castro, T; Plascencia-Jatomea, M; Rodríguez-Félix, F; Herrera-Franco, P J

    2014-01-30

    Novel films of polyethylene and chitosan were obtained using extrusion. These polymers have interesting properties, and processing them with methods that are of high use in the industry, such as the extrusion method, can have a significant effect on the potential applications of these materials. The individual materials were thermally characterized; after this, extruded films of low density polyethylene and chitosan mixtures were prepared with the addition of polyethylene-graft-maleic anhydride as a compatibilizer for the blends, and glycerol, as a plasticizer for chitosan. The use of compatibilizer and plasticizer agents improved the processability and compatibility of the mixtures, as well as their mechanical properties, as revealed by mechanical property measurements and scanning electron microscopy. It was possible to prepare blends with a maximum chitosan content of 20 wt%. The material stiffness increased with the increase of chitosan in the sample. FTIR studies revealed the existence of an interaction between the compatibilizer and chitosan.

  11. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, D.; Waller, F.J.

    1999-04-06

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  12. IDENTIFYING AIRWAY SENSITIZERS: MRNA CYTOKINE PROFILES INDUCED BY VARIOUS ANHYDRIDES

    EPA Science Inventory

    Abstract:
    Exposure to low molecular weight (LMW) chemicals in the workplace has been linked to a variety of respiratory effects. Within the LMW chemicals, one of the major classes involved in these effects are the acid anhydrides. The immunological basis of respiratory hyp...

  13. Rheological studies on the reaction of zein with polyethylenemaleic anhydride

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There continues to be interest in developing solvent-resistant articles from biobased renewable materials to successfully complete with petro-chemical products. It was previously shown that reaction of zein with polyethylenemaleic anhydride (PEMA) provides articles that are solvent-resistant. The ge...

  14. Nickel-catalyzed decarboxylative carboamination of alkynes with isatoic anhydrides.

    PubMed

    Yoshino, Yasufumi; Kurahashi, Takuya; Matsubara, Seijiro

    2009-06-10

    An intermolecular nickel-catalyzed addition reaction in which isatoic anhydrides react with alkynes to afford substituted quinolones has been developed. A mechanistic rationale is proposed, implying oxidative addition of Ni(0) to a carbamate, which allows intermolecular addition to alkynes via decarboxylation.

  15. Condensation of anhydrides or dicarboxylic acids with compounds containing active methylene groups. Part 1: Condensation of phthalic anhydride with acetoacetic and malonic ester

    NASA Technical Reports Server (NTRS)

    Oshkaya, V. P.; Vanag, G. Y.

    1985-01-01

    Phthalic anhydride was condensed with acetoacetic ester in acetic anhydride and triethylamine solution, and when phthalyl chloride was reacted with sodium acetoacetic ester compounds were formed of the phthalide and indandione series: phthalylacetoacetic ester and a derivative of indan-1,3-dione which after boiling with hydrochloric acid yielded indan-1,3-dione. Phthalylmalonic ester was obtained from phthalic anhydride and malonic ester in the presence of triethylamine.

  16. Substituted isatoic anhydrides: selective inactivators of trypsin-like serine proteases.

    PubMed

    Gelb, M H; Abeles, R H

    1986-04-01

    Derivatives of isatoic anhydride were prepared and tested as inhibitors of serine proteases. A number of isatoic anhydrides with positively charged substituents irreversibly inactivated several trypsin-like enzymes and preferentially inactivated trypsin over chymotrypsin. Further selectivity was obtained by introduction of an aromatic group on the N-1 position of isatoic anhydride. 7-(Aminomethyl)-1-benzylisatoic anhydride was prepared and was a selective inactivator of thrombin; thus it is possible to prepare derivatives of isatoic anhydride that are highly enzyme selective without attaching peptide recognition structures.

  17. International Topical Workshop on Advances in Silicon-Based Polymer Science (2nd) Held in Makaha, Oahu, Hawaii on December 16-20, 1990

    DTIC Science & Technology

    1990-12-20

    monofunctional reagents such as phthalic anhydride and maleic anhydride , yielding nonreactive or potentially reactive endgroups, respectively...polymerization will be discussed, i.e., formation of ionic aggregates, interactions with monomer and polymer and complexes with nucleophilic additives. In the...pattern of the process. The second major discussed problem will be kinetics and mecha- nism of the formation of oligomers in the polymerization

  18. Tailoring polymer properties with layered silicates

    NASA Astrophysics Data System (ADS)

    Xu, Liang

    Polymer layered silicate nanocomposites have found widespread applications in areas such as plastics, oil and gas production, biomedical, automotive and information storage, but their successful commercialization critically depends on consistent control over issues such as complete dispersion of layered silicate into the host polymer and optimal interaction between the layered silicates and the polymers. Polypropylene is a commercially important polymer but usually forms intercalated structures with organically modified layered silicate upon mixing, even it is pre-treated with compatibilizing agent such as maleic anhydride. In this work, layered silicate is well dispersed in ammonium modified polypropylene but does not provide sufficient reinforcement to the host polymer due to poor interactions. On the other hand, interactions between maleic anhydride modified polypropylene and layered silicate are fine tuned by using a small amount of maleic anhydride and mechanical strength of the resultant nanocomposites are significantly enhanced. In particular, the melt rheological properties of layered silicate nanocomposites with maleic anhydride functionalized polypropylene are contrasted to those based on ammonium-terminated polypropylene. While the maleic anhydride treated polypropylene based nanocomposites exhibit solid-like linear dynamic behavior, consistent with the formation of a long-lived percolated nanoparticle network, the single-end ammonium functionalized polypropylene based nanocomposites demonstrated liquid-like behavior at comparable montmorillonite concentrations. The differences in the linear viscoelasticity are attributed to the presence of bridging interaction in maleic anhydride functionalized nanocomposites, which facilitates formation of a long-lived silicate network mediated by physisorbed polymer chains. Further, the transient shear stress of the maleic anhydride functionalized nanocomposites in start-up of steady shear is a function of the shear

  19. Relationship of airborne trimellitic anhydride concentrations to trimellitic anhydride--induced symptoms and immune responses

    SciTech Connect

    Bernstein, D.I.; Roach, D.E.; McGrath, K.G.; Larsen, R.S.; Zeiss, C.R.; Patterson, R.

    1983-12-01

    Eighteen workers exposed to trimellitic anhydride (TMA) powder were evaluated in 1979. Twelve of these workers were available for longitudinal study until 1982. Annual clinical evaluations and serum radioimmunoassays for total antibody binding and specific IgE binding to /sup 125/I-TM-HSA were performed. In 1979, five workers had antibody against TM-HSA. Of these, three workers were diagnosed with the late respiratory systemic syndrome (LRSS) and one worker with TMA-induced allergic rhinitis. The LRSS workers had significantly elevated total antibody binding of /sup 125/I-TM-HSA and the worker with rhinitis had significantly elevated specific IgE binding of /sup 125/I-TM-HSA per milliliter of serum. Although TMA handling was intermittent throughout the year, average airborne dust concentrations from 1974 to 1978 at job stations of the two heaviest TMA-exposed occupations, operator and assistant operator, were 2.1 and 0.82 mg/m3, respectively. After local exhaust ventilation had been improved, average airborne dust concentrations of TMA at the two latter job stations fell to levels of 0.03 and 0.01 mg/m3, respectively, in 1982. The decrease in TMA exposure coincided with a gradual fall in total antibody binding of /sup 125/I-TM-HSA per milliliter in 1982 and symptomatic improvement in the three individuals with the LRSS. The continuous low-level exposure of the worker with TMA rhinitis was sufficient to elicit a rise in specific IgE against TM-HSA from 1.1 ng of 125I-TM-HSA bound per milliliter in 1979 to 2.12 in 1982.

  20. Chitosan: poly( N-vinylpyrrolidone- alt-itaconic anhydride) nanocapsules—a promising alternative for the lung cancer treatment

    NASA Astrophysics Data System (ADS)

    Raţă, Delia Mihaela; Chailan, Jean-François; Peptu, Cătălina Anişoara; Costuleanu, Marcel; Popa, Marcel

    2015-07-01

    This study reports the preparation of novel polymeric nanocapsules based on a natural polymer, chitosan and a synthetic one, poly( N-vinylpyrrolidone- alt-itaconic anhydride) [(poly(NVPAI)] using an interfacial condensation technique. The infrared spectroscopy studies confirmed the crosslinking through the presence of amide bonds, formed between the two polymers chains. The diameter of nanocapsules was found in the range of 126-214 nm and it was determined by dynamic light scattering method. Morphological characterization demonstrated their nano size, the spherical shape of the nanocapsules and the formation of hollow particles. The nanocapsules presented good swelling capacity in aqueous solutions. 5-Fluorouracil (5-FU) loading and release capacity was studied, the processes being controlled by the drug diffusion through the polymeric membrane. The obtained results were encouraging, showing that 5-FU-loaded nanocapsules had 70 % higher apoptotic effect on A549 tumour cells than the drug in free state or mixed with the nanocapsules.

  1. Properties of polyethylene films with incorporated benzoic anhydride and/or ethyl and propyl esters of 4-hydroxybenzoic acid and their suitability for food packaging.

    PubMed

    Dobiás, J; Chudackova, K; Voldrich, M; Marek, M

    2000-12-01

    Benzoic anhydride and ethyl and propyl esters of 4-hydroxybenzoic acid (ETP and PRP, respectively, also termed parabens) incorporated into low density polyethylene (LDPE) film were studied with regard to migration into food and food simulants at 6 degrees C and 25 degrees C, and changes in selected properties of the film were investigated. Antimicrobials were incorporated into polymer film in concentrations of 5 g/kg and 10 g/kg. The addition of parabens into the polymer was more difficult than benzoic anhydride due to their volatility. For benzoic anhydride, 30-40% and 10-20% of the added amount was found to leach from the film into aqueous and olive oil food simulants, respectively. The migration into both water and olive oil followed a very similar course in the case of parabens. Migration levels over 90% and in the range of 70% to 80%, relative to the amount of agent in the film, were determined for ETP and PRP respectively. The incorporation of antimicrobials into the film significantly changed the functional characteristics of the packaging material, i.e. permeability of oxygen, carbon dioxide and water vapour, tensile strength, coefficient of friction, sealing strength and transparency. Shelf life tests with packaged cheese and toasted bread demonstrated the efficiency of the film containing 10 g/kg of BA against mould growth on the food surface during storage at 6 degrees C.

  2. Delayed and immediate allergy caused by methylhexahydrophthalic anhydride.

    PubMed

    Kanerva, L; Hyry, H; Jolanki, R; Hytönen, M; Estlander, T

    1997-01-01

    Epoxy resin compounds (ERC) include a large number of chemicals, such as epoxy resins (ER), reactive diluents and hardeners. Many hardeners, e.g., aliphatic polyamines, are well-known sensitizers. Another type of ER hardeners are the phthalic anhydrides, such as methylhexahydrophthalic anhydride (MHHPA) and methyltetrahydrophthalic anhydride (MTHPA), which have been reported as causing immunologically-mediated respiratory diseases and contact urticaria, but not allergic contact dermatitis. Here, we present a horizontal boring-machine worker who developed allergic contact dermatitis, as well as allergic rhinitis and an immediate contact skin reaction from MHHPA. Patch testing with a dilution series of MHHPA in pet. elicited the following results: 2%, 1% and 0.5%, +2; 0.25% and 0.125%, + (3- to 6-day readings). An immunohistochemical and electron microscopic study also indicated that the patch test reactions were conventional-delayed allergic reactions. Interleukin 8 was observed in the epidermal cells, whereas interleukin 4 immunoreactivity was detected in the dermal cells. Immunoreactivity to-interleukin 5, granulocyte/macrophage-colophony stimulating factor (GM-CSF) or eosinophil cationic protein was not seen. In conclusion, the patient developed both Type I and Type IV allergy to MHHPA. The clinical data, patch test results, immunohistochemical and electron microscopic observations indicated that the MHHPA allergy detected by the patch test reaction was a conventional delayed-type hypersensitivity reaction. The patient also had an allergic patch test reaction to para-phenylenediamine and diaminodiphenylmethane, possibly representing occupational sensitization.

  3. Experimental and Computational Thermochemistry of 3- and 4-Nitrophthalic Anhydride.

    PubMed

    García-Castro, Miguel Ángel; Amador, Patricia; Hernández-Pérez, Julio Manuel; Medina-Favela, Adrián Eduardo; Flores, Henoc

    2014-05-08

    In order to understand the influence that the position of the nitro group on the aromatic ring has on the relative stability of two isomers, the standard enthalpies of formation of 3- and 4-nitrophthalic anhydride in the gaseous phase, at T = 298.15 K, were obtained by experimental thermochemistry and theoretical studies. The standard enthalpies of formation in the crystalline phase, at T = 298.15 K, were obtained by combustion calorimetry and the enthalpies of sublimation by the Knudsen method. For the theoretical calculations, a standard ab initio molecular orbital method at the G3 level was used. The enthalpies of formation in the gaseous phase were obtained from atomization and isodesmic reactions. A theoretical study of the molecular and electronic structures of these compounds was also performed. Differences of -9.7 kJ•mol-1, for 3-nitrophthalic anhydride, and -2.6 kJ•mol-1 for 4-nitrophthalic anhydride, were found from a comparison between our theoretical and experimental results.

  4. Soy protein polymers: Enhancing the water stability property

    NASA Astrophysics Data System (ADS)

    Srinivasan, Gowrishankar

    Soy protein based plastics have been processed in the past by researchers for various short-term applications; however a common issue is the high water sensitivity of these plastics. This work concentrates on resolving this water sensitivity issue of soy protein polymers by employing chemical and mechanical interaction at the molecular level during extrusion. The primary chemical interactions employed were anhydride chemistries such as maleic anhydride (MA), phthalic anhydride (PTA), and butylated hydroxyanisole (BHA). These were respectively used in conjunction with glycerol as a plasticizer to produce relatively water stable soy protein based plastics. Formulations with varying additive levels of the chemistries were extruded and injection molded to form the samples for characterization. The additive levels of anhydrides were varied between 3-10% tw/tw (total mass). Results indicated that phthalic anhydride formulations resulted in highest water stability. Plastic formulations with concentration up to 10% phthalic anhydride were observed to have water absorption as low as 21.5% after 24 hrs of exposure to water with respect to 250% for the control formulation. Fourier transform infrared spectroscopy (FTIR) was utilized to characterize and confirm the fundamental mechanisms of water stability achieved by phthalic and maleic anhydride chemistries. In addition, the anhydride formulations were modified by inclusion of cotton fibers and pretreated cotton powder in order to improve mechanical properties. The incorporation of cotton fibers improved the dry strength by 18%, but did not significantly improve the wet state strength of the plastics. It was also observed that the butylated-hydroxy anisole (BHA) formulation exhibited high extension values in the dry state and had inferior water absorption properties in comparison with anhydride formulations.

  5. Chain-length-dependent autocatalytic hydrolysis of fatty acid anhydrides in polyethylene glycol.

    PubMed

    Cao, Cao; Wang, Qing-Biao; Tang, Lin-Jun; Ge, Bing-Qiang; Chen, Zhong-Xiu; Deng, Shao-Ping

    2014-03-27

    Autocatalytic hydrolysis of fatty acid anhydrides induced by the spontaneously formed vesicles has been studied for years. However, whether the reaction autocatalyzed by vesicles formed in diluted solutions applies also to macromolecular crowded conditions remains unknown. The aim of this study is to characterize hydrolysis behavior of fatty acid anhydrides and formation of vesicles in crowded media. Inert macromolecular crowding agents such as polyethylene glycol (PEG) and Dextran were used to probe the impact of external crowding on the autocatalytic hydrolysis of fatty acid anhydrides with varied hydrophobic chain length. Under stringent conditions of crowding, hydrolysis rates of octanoic anhydride, nonanoic anhydride, and decanoic anhydride were found to decrease, but the rates of lauric anhydride and oleic anhydride increased. These results suggest that the effect of the crowding agent on the hydrolysis of fatty acid anhydrides was chain-length-dependent. Characterization of the size and polydispersity of vesicles formed from hydrolyzed fatty acid anhydrides in crowding revealed that long-chain fatty acids formed monodisperse vesicles easier at lower concentrations of PEG. Measurement of the critical aggregation concentration of ionized fatty acid in the presence of PEG showed that crowding media promoted vesicle formation from long-chain fatty acids but inhibited those from fatty acids with fewer carbon atoms. Further investigation of the diffusion property of ionized fatty acids in crowding agents suggested that PEG might create more hydrophobic areas for long-chain fatty acids anhydrides, which subsequently promoted the unreacted anhydride in the aqueous phase to be solubilized in the formed vesicles. This research provides information for understanding the autocatalytic reaction accompanied by self-producing aggregates and the behavior of fatty acids in crowding media.

  6. Are isatin and isatoic anhydride antiaromatic and aromatic respectively? A combined experimental and theoretical investigation.

    PubMed

    Matos, M Agostinha R; Miranda, Margarida S; Morais, Victor M; Liebman, Joel F

    2003-07-21

    This paper reports the results of our thermochemical/calorimetric determination of the enthalpies of combustion, phase change, and formation of isatin, isatoic anhydride, and N-methylisatin. The density functional calculations accompanied by vibrational and thermal corrections were also performed for these compounds and N-methylisatoic anhydride. Through a combination of theoretical calculations and associated isodesmic reactions, we have deduced that isatin has some antiaromatic character and isatoic anhydride enjoys some aromatic stabilization.

  7. Tall oil fatty acid anhydrides as corrosion inhibitor intermediates

    SciTech Connect

    Fischer, E.R.; Parker, J.E. III

    1995-12-01

    Electrochemical corrosion of carbon steel tubulars in producing oil wells causes lost production and necessitates costly repairs. Corrosive environments exists where hydrocarbons and an aqueous phase are being extracted from producing wells. Tubing life has been extended four fold with the development of organic corrosion inhibitors and concentric configuration treatment. Anhydrides derived from tall oil fatty acids offer enhanced corrosion inhibition properties as compared to traditional dimer/trimer acids. The chemistry of this intermediate and its use in corrosion inhibition for down hole applications, as well as the synthesis of novel oil and water-soluble derivatives will be discussed.

  8. The properties of poly(lactic acid)/starch blends with a functionalized plant oil: tung oil anhydride.

    PubMed

    Xiong, Zhu; Li, Chao; Ma, Songqi; Feng, Jianxian; Yang, Yong; Zhang, Ruoyu; Zhu, Jin

    2013-06-05

    Bio-sourced polymers, polylactide (PLA) and starch, have been melt-blended by lab-scale co-extruder with tung oil anhydride (TOA) as the plasticizer. The ready reaction between the maleic anhydride on TOA and the hydroxyl on starch led TOA molecules to accumulate on starch and increased the compatibility of PLA/starch blends, which was confirmed by FT-IR analyses and SEM. The TOA could change the mechanical properties and physical behaviors of PLA/starch blends. DSC and DMA analysis show that the TOA layer on starch has an effect on the thermal behavior of PLA in the ternary blend. The enrichment of TOA on starch improves the toughness and impact strength of the PLA/starch blends. The adding amount of TOA in PLA/starch blends primarily determined the compatibility and mechanical properties of the resulted ternary blends. The tensile and impact fracture modes of the PLA/starch blend with or without TOA has also been investigated by SEM analysis.

  9. Separator Membrane from Crosslinked Poly(Vinyl Alcohol) and Poly(Methyl Vinyl Ether-alt-Maleic Anhydride)

    PubMed Central

    Rohatgi, Charu Vashisth; Dutta, Naba K.; Choudhury, Namita Roy

    2015-01-01

    In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA) with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MA). Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined for their potential use as membranes or separators for batteries. Therefore, the chemical interactions between these two polymers and the influence of such crosslinking on physicochemical properties of the membrane are systematically investigated through rheology and by critical gel point study. The hydrogen bonding and the chemical interaction between PMVE-MA and PVA resulted in highly cross-linked membranes. Effect of the molecular weight of PVA on the membrane properties was also examined. The developed membranes were extensively characterized by studying their physicochemical properties (water uptake, swelling ratio, and conductivity), thermal and electrochemical properties using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The DSC study shows the presence of a single Tg in the membranes indicating compatibility of the two polymers in flexible and transparent films. The membranes show good stability and ion conductivity suitable for separator applications. PMID:28347019

  10. The energetics of isomeric benzoxazine diones: isatoic anhydride revisited.

    PubMed

    Matos, M Agostinha R; Miranda, Margarida S; Morais, Victor M F; Liebman, Joel F

    2004-06-07

    The standard (p(o) = 0.1 MPa) molar enthalpy of formation of crystalline 2H-1,3-benzoxazine-2,4(3H)dione was measured, at T= 298.15 K, by static bomb calorimetry and the standard molar enthalpy of sublimation, at T= 298.15 K, was obtained using Calvet microcalorimetry. These values were used to derive the standard molar enthalpy of formation in the gaseous phase, T= 298.15 K, of -(401.0 +/- 3.5) kJ mol(-1). The standard molar enthalpy of sublimation of isatoic anhydride was recalculated, and our recommended experimental value for the standard molar enthalpy of formation in the gaseous phase, T= 298.15 K, is -(406.2 +/- 3.4) kJ mol(-1). Density functional calculations for the two isomers 2H-1,3-benzoxazine-2,4(3H)dione and isatoic anhydride, in which the ring nitrogen and oxygen have been transposed, confirm the experimental evidence of nearly identical thermochemical stability for these isomers.

  11. Synthesis and hydrolysis behaviour of poly(ester anhydrides) from polylactone precursors containing alkenyl moieties.

    PubMed

    Korhonen, Harri; Hakala, Risto A; Helminen, Antti O; Seppälä, Jukka V

    2006-07-14

    Hydroxyl-group functional polylactones were prepared and converted to acid- terminated polyesters in a reaction with a series of alkenylsuccinic anhydrides containing 8, 12, or 18 carbons in their alkenyl chains. These polyester precursors were then linked into higher molecular weight poly(ester anhydrides) containing alkenyl moieties in their polyester blocks. The hydrolysis behaviour of the poly(ester anhydrides) was found to depend on the thermal properties of the polyester precursors. For poly(ester anhydrides) prepared from low molecular weight prepolymers with thermal transitions below 37 degrees C, the presence of hydrophobic alkenyl chains in the polyester precursors slowed the rate of weight loss. Poly(ester anhydrides) prepared from higher molecular weight prepolymers showed the opposite weight-loss behaviour; i.e., the crystallinity and thermal transitions of the alkenyl chain-containing poly(ester anhydrides) were low, and the weight loss was faster than for poly(ester anhydrides) without the alkenyl chains. The differences in length of the alkenyl chain, as such, had little effect on the hydrolysis behaviour and thermal properties of the poly(ester anhydrides).

  12. Initiation precursors and initiators in laser-induced copolymerization of styrene and maleic anhydride in acetone

    NASA Technical Reports Server (NTRS)

    Miner, Gilda A.; Meador, Willard E.; Chang, C. Ken

    1990-01-01

    The initiation step of photopolymerized styrene/maleic anhydride copolymer was investigated at 365 nm. UV absorption measurements provide decisive evidence that the styrene/maleic anhydride charge transfer complex is the sole absorbing species; however, key laser experiments suggest intermediate reactions lead to a monoradical initiating species. A mechanism for the photoinitiation step of the copolymer is proposed.

  13. Palladium-catalyzed carbonylation of o-iodoanilines for synthesis of isatoic anhydrides.

    PubMed

    Gao, Sha; Chen, Ming; Zhao, Mi-Na; Du, Wei; Ren, Zhi-Hui; Wang, Yao-Yu; Guan, Zheng-Hui

    2014-05-02

    A novel palladium-catalyzed oxidative double carbonylation of o-iodoanilines for the synthesis of isatoic anhydrides has been developed. The reaction employs readily available o-iodoanilines as the starting materials and proceeds under mild conditions. For extension, palladium-catalyzed oxidative carbonylation of anthranilic acids was developed for the synthesis of substituted isatoic anhydrides in high to excellent yields.

  14. 40 CFR 721.9270 - Reaction product of epoxy with anhydride and glycerol and glycol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Reaction product of epoxy with... Significant New Uses for Specific Chemical Substances § 721.9270 Reaction product of epoxy with anhydride and... substance identified generically as reaction product of epoxy with anhydride and glycerol and glycol (PMN...

  15. 40 CFR 721.9270 - Reaction product of epoxy with anhydride and glycerol and glycol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Reaction product of epoxy with... Significant New Uses for Specific Chemical Substances § 721.9270 Reaction product of epoxy with anhydride and... substance identified generically as reaction product of epoxy with anhydride and glycerol and glycol (PMN...

  16. 40 CFR 721.9270 - Reaction product of epoxy with anhydride and glycerol and glycol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Reaction product of epoxy with... Significant New Uses for Specific Chemical Substances § 721.9270 Reaction product of epoxy with anhydride and... substance identified generically as reaction product of epoxy with anhydride and glycerol and glycol (PMN...

  17. 40 CFR 721.9270 - Reaction product of epoxy with anhydride and glycerol and glycol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Reaction product of epoxy with... Significant New Uses for Specific Chemical Substances § 721.9270 Reaction product of epoxy with anhydride and... substance identified generically as reaction product of epoxy with anhydride and glycerol and glycol (PMN...

  18. 40 CFR 721.9270 - Reaction product of epoxy with anhydride and glycerol and glycol.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Reaction product of epoxy with... Significant New Uses for Specific Chemical Substances § 721.9270 Reaction product of epoxy with anhydride and... substance identified generically as reaction product of epoxy with anhydride and glycerol and glycol (PMN...

  19. TRIMELLITIC ANHYDRIDE-INDUCED EOSINOPHILIA IN A MURINE MODEL OF OCCUPATIONAL ASTHMA

    EPA Science Inventory

    TRIMELLITIC ANHYDRIDE-INDUCED EOSINOPHILIA IN A MURINE MODEL OF OCCUPATIONAL ASTHMA. J F Regal, ME Mohrman, E Boykin and D Sailstad. Dept. of Pharmacology, University of Minnesota, Duluth, MN, USA and NHEERL, ORD, US EPA, RTP, NC, USA.
    Trimellitic anhydride (TMA) is a small m...

  20. Effect of maleic anhydride treatment on the mechanical properties of sansevieria fiber/vinyl ester composites

    NASA Astrophysics Data System (ADS)

    Pradipta, Rangga; Mardiyati, Steven, Purnomo, Ikhsan

    2017-03-01

    Sanseviera trifasciata commonly called mother-in-law tongue also known as snake plant is native to Indonesia, India and Africa. Sansevieria is a new fiber in composite research and has showed promising properties as reinforcement material in polymer matrix composites. Chemical treatment on reinforcing fiber is crucial to reduce hydrophilic tendency and thus improve compatibility with the matrix. In this study, effect of maleic anhydride as chemical treatment on the mechanical properties of Sansevieria fiber/vinyl ester composite was investigated. Sansevieria fibers were immersed by using NaOH 3% for two hours at 100°C and then treated by using maleic anhydrate for two hours at 120°C. Composites were prepared by solution casting with various volume fractions of fiber; 0%, 2.5%, 5%, 7.5% and 10%. Actual density, volume fraction of void and mechanical properties of composite were conducted according to ASTM standard testing methods D792, D3171 and D3039. It was found that mechanical properties of composites increased as volume fractions of fiber was increased. The highest tensile strength and modulus of elasticity of composites were 57.45 MPa and 3.47 GPa respectively, obtained from composites with volume fraction of fiber 10%.

  1. Oral delivery of insulin loaded poly(fumaric-co-sebacic) anhydride microspheres.

    PubMed

    Furtado, Stacia; Abramson, Danielle; Burrill, Roxanne; Olivier, Gloria; Gourd, Celinda; Bubbers, Emily; Mathiowitz, Edith

    2008-01-22

    The bioadhesive polymer, poly(fumaric-co-sebacic) anhydride, p(FASA), was used to fabricate small diameter insulin microspheres and evaluate their in vivo performance in a type 1 diabetic rat as well as a type 1 diabetic dog model. The process of phase inversion nanoencapsulation was used to fabricate p(FASA) microspheres containing insulin. Using laser diffraction spectrometry, 90% of the microspheres used in the fed double dose rat experiments were found to have a volumetric diameter of 5.9 microm or smaller. In comparison, 90% of the microspheres used in fed single dose rat experiments were found to have a volumetric diameter of 2.6 microm or smaller while the microspheres used in the diabetic dog experiments were found to have a volumetric diameter of 1.2 microm or smaller. Insulin microspheres administered to diabetic rats in the fed double dose experiment produced a relative bioavailability (RB) of 23.3% while insulin microspheres administered to diabetic rats in the fed single dose experiment produced a RB of 5.5+/-1.7%. Insulin microspheres administered to fasted diabetic dogs produced a RB of 5.5+/-3.4%.

  2. Locally delivered salicylic acid from a poly(anhydride-ester): impact on diabetic bone regeneration.

    PubMed

    Wada, Keisuke; Yu, Weiling; Elazizi, Mohamad; Barakat, Sandrine; Ouimet, Michelle A; Rosario-Meléndez, Roselin; Fiorellini, Joseph P; Graves, Dana T; Uhrich, Kathryn E

    2013-10-10

    Diabetes mellitus (DM) involves metabolic changes that can impair bone repair, including a prolonged inflammatory response. A salicylic acid-based poly(anhydride-ester) (SA-PAE) provides controlled and sustained release of salicylic acid (SA) that locally resolves inflammation. This study investigates the effect of polymer-controlled SA release on bone regeneration in diabetic rats where enhanced inflammation is expected. Fifty-six Sprague-Dawley rats were randomly assigned to two groups: diabetic group induced by streptozotocin (STZ) injection or normoglycemic controls injected with citrate buffer alone. Three weeks after hyperglycemia development or vehicle injection, 5mm critical sized defects were created at the rat mandibular angle and treated with SA-PAE/bone graft mixture or bone graft alone. Rats were euthanized 4 and 12weeks after surgery, then bone fill percentage in the defect region was assessed by micro-computed tomography (CT) and histomorphometry. It was observed that bone fill increased significantly at 4 and 12weeks in SA-PAE/bone graft-treated diabetic rats compared to diabetic rats receiving bone graft alone. Accelerated bone formation in normoglycemic rats caused by SA-PAE/bone graft treatment was observed at 4weeks but not at 12weeks. This study shows that treatment with SA-PAE enhances bone regeneration in diabetic rats and accelerates bone regeneration in normoglycemic animals.

  3. Dinuclear Zinc Salen Catalysts for the Ring Opening Copolymerization of Epoxides and Carbon Dioxide or Anhydrides.

    PubMed

    Thevenon, Arnaud; Garden, Jennifer A; White, Andrew J P; Williams, Charlotte K

    2015-12-21

    A series of four dizinc complexes coordinated by salen or salan ligands, derived from ortho-vanillin and bearing (±)-trans-1,2-diaminocyclohexane (L1) or 2,2-dimethyl-1,3-propanediamine (L2) backbones, is reported. The complexes are characterized using a combination of X-ray crystallography, multinuclear NMR, DOSY, and MALDI-TOF spectroscopies, and elemental analysis. The stability of the dinuclear complexes depends on the ligand structure, with the most stable complexes having imine substituents. The complexes are tested as catalysts for the ring-opening copolymerization (ROCOP) of CO2/cyclohexene oxide (CHO) and phthalic anhydride (PA)/CHO. All complexes are active, and the structure/activity relationships reveal that the complex having both L2 and imine substituents displays the highest activity. In the ROCOP of CO2/CHO its activity is equivalent to other metal salen catalysts (TOF = 44 h(-1) at a catalyst loading of 0.1 mol %, 30 bar of CO2, and 80 °C), while for the ROCOP of PA/CHO, its activity is slightly higher than other metal salen catalysts (TOF = 198 h(-1) at a catalyst loading of 1 mol % and 100 °C). Poly(ester-block-carbonate) polymers are also afforded using the most active catalyst by the one-pot terpolymerization of PA/CHO/CO2.

  4. Modification of wheat starch with succinic acid/acetic anhydride and azelaic acid/acetic anhydride mixtures I. Thermophysical and pasting properties.

    PubMed

    Subarić, Drago; Ačkar, Durđica; Babić, Jurislav; Sakač, Nikola; Jozinović, Antun

    2014-10-01

    The aim of this research was to investigate the influence of modification with succinic acid/acetic anhydride and azelaic acid/acetic anhydride mixtures on thermophysical and pasting properties of wheat starch. Starch was isolated from two wheat varieties and modified with mixtures of succinic acid and acetic anhydride, and azelaic acid and acetic anhydride in 4, 6 and 8 % (w/w). Thermophysical, pasting properties, swelling power, solubility and amylose content of modified starches were determined. The results showed that modifications with mixtures of afore mentioned dicarboxylic acids with acetic anhydride decreased gelatinisation and pasting temperatures. Gelatinisation enthalpy of Golubica starch increased, while of Srpanjka starch decreased by modifications. Retrogradation after 7 and 14 day-storage at 4 °C decreased after modifications of both starches. Maximum, hot and cold paste viscosity of both starches increased, while stability during shearing at high temperatures decreased. % setback of starches modified with azelaic acid/acetic anhydride mixture decreased. Swelling power and solubility of both starches increased by both modifications.

  5. Risk factors for sensitisation and respiratory symptoms among workers exposed to acid anhydrides: a cohort study

    PubMed Central

    Barker, R. D.; van Tongeren, M. J.; Harris, J. M.; Gardiner, K.; Venables, K. M.; Newman, T

    1998-01-01

    OBJECTIVES: To examine the relation between exposure to acid anhydrides and the risk of developing immediate skin prick test responses to acid anhydride human serum albumin (AA-HSA) conjugates or work related respiratory symptoms; to assess whether these relations are modified by atopy or smoking. METHODS: A cohort of 506 workers exposed to phthalic (PA), maleic (MA), and trimellitic anhydride (TMA) was defined. Workers completed questionnaires relating to employment history, respiratory symptoms, and smoking habits. Skin prick tests were done with AA-HSA conjugates and common inhalant allergens. Exposure to acid anhydrides was measured at the time of the survey and a retrospective exposure assessment was done. RESULTS: Information was obtained from 401 (79%) workers. Thirty four (8.8%) had new work related respiratory symptoms that occurred for the first time while working with acid anhydrides and 12 (3.2%) were sensitised, with an immediate skin prick test reaction to AA-HSA conjugates. Sensitisation to acid anhydrides was associated with work related respiratory symptoms and with smoking at the time of exposure to acid anhydride. When all subjects were included and all three acid anhydrides were taken into account there was no consistent evidence for an exposure-response relation, but with the analysis restricted to a factory where only TMA was in use there was an increased prevalence of sensitisation to acid anhydrides and work related respiratory symptoms with increasing full shift exposure. This relation was apparent within the current occupational exposure standard of 40 micrograms.m-3 and was not modified significantly by smoking or atopy. CONCLUSIONS: Intensity of exposure and cigarette smoking may be risk factors for sensitisation to acid anhydrides. Exposure is also a risk factor for respiratory symptoms. As there was evidence for sensitisation to TMA at full shift exposures within the occupational exposure standard this standard should be reviewed.

  6. Low Viscosity Imides Based on Asymmetric Oxydiphthalic Anhydride

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Criss, Jim M., Jr.; Mintz, Eric A.; Scheiman, Daniel A.; Nguyen, Baochau N.; McCorkle, Linda S.

    2008-01-01

    A series of low-melt viscosity imide resins were prepared from asymmetric oxydiphthalic dianhydride (a-ODPA) and 4-phenylethynylphthalic anhydride as the endcap, along with 3,4' - oxydianiline (3,4' -ODA), 3,4' -methylenedianiline (3,4' -MDA), 3,3' -methylenedianiline (3,3' - MDA) and 3,3'-diaminobenzophenone (3,3'-DABP), using a solvent-free melt process. These imide oligomers displays low-melt viscosities (2-15 poise) at 260-280 C, which made them amenable to low-cost resin transfer molding (RTM) process. The a-ODPA based RTM resins exhibits glass transition temperatures (Tg's) in the range of 265-330 C after postcure at 343 C. The mechanical properties of these polyimide/carbon fiber composites fabricated by RTM will be discussed.

  7. Acetylation of barnyardgrass starch with acetic anhydride under iodine catalysis.

    PubMed

    Bartz, Josiane; Goebel, Jorge Tiago; Giovanaz, Marcos Antônio; Zavareze, Elessandra da Rosa; Schirmer, Manoel Artigas; Dias, Alvaro Renato Guerra

    2015-07-01

    Barnyardgrass (Echinochloa crus-galli) is an invasive plant that is difficult to control and is found in abundance as part of the waste of the paddy industry. In this study, barnyardgrass starch was extracted and studied to obtain a novel starch with potential food and non-food applications. We report some of the physicochemical, functional and morphological properties as well as the effect of modifying this starch with acetic anhydride by catalysis with 1, 5 or 10mM of iodine. The extent of the introduction of acetyl groups increased with increasing iodine levels as catalyst. The shape of the granules remained unaltered, but there were low levels of surface corrosion and the overall relative crystallinity decreased. The pasting temperature, enthalpy and other gelatinisation temperatures were reduced by the modification. There was an increase in the viscosity of the pastes, except for the peak viscosity, which was strongly reduced in 10mM iodine.

  8. Evaluation of copolymer conformation states of vinylchloride-maleic anhydride

    NASA Astrophysics Data System (ADS)

    Ivanov, A. A.

    2016-11-01

    The quantum-chemical analysis and experimental study of alternating vinylchloride-maleic anhydride (VC-MA) copolymer macromolecules with polymerization degree 600 have been carried out. The VC-MA copolymer in solvents of different nature undergoes cycloanhydride-enol tautomerism and the macromolecules take the form of corrugated sticks according to viscometric measurements. The computer simulation has shown that the segment with polymerization degree n < 18 (model compound) is not a helix and rolls while if n = 18 the conformations get distorted. The model molecule optimal structure comprising a random sequence of alternating units of comonomers and their enol tautomers with minimal system total energy has been found by the semiempirical parametric method PM3.

  9. Perylenetetracarboxylic anhydride as a precursor of fluorescent carbon nanoonion rings

    NASA Astrophysics Data System (ADS)

    Baldoví, Herme G.; Herance, José Raul; Manuel Víctor, Víctor; Alvaro, Mercedes; Garcia, Hermenegildo

    2015-07-01

    Thermal annealing at 400 °C of perylenetetracarboxylic anhydride in low molecular mass PEG gives rise to the formation of well defined nanoobjects of 2.5 nm height and size distribution from 10 to 65 nm (average 40 nm) after purification of the raw mixture with silicagel chromatography. TEM reveals that the flat nanoobjects are constituted of concentric graphenic rings (0.34 nm interlayer distance). The morphology of the nanoparticles resembles onion rings of nanometric dimensions (nanoonion rings C-NOR). C-NOR particles have an excitation dependent emission with λem from 430 to 570 nm and a maximum emission quantum yield of 0.49. C-NOR particles can be internalized into Hep3B human hepatoma cells as determined by confocal fluorescence microscopy and are remarkably biocompatible affecting slightly cell viability according to the MTT test.

  10. Carboxy terminated rubber based on natural rubber grafted with acid anhydrides and its adhesion properties

    NASA Astrophysics Data System (ADS)

    Klinpituksa, P.; Kongkalai, P.; Kaesaman, A.

    2014-08-01

    The chemical modification of natural rubber by grafting of various polar functional molecules is an essential method, improving the versatility of rubber in applications. This research investigated the preparation of natural rubber-graft-citraconic anhydride (NR-g-CCA), natural rubber-graft-itaconic anhydride (NR-g-ICA), and natural rubber-graft-maleic anhydride (NR-g-MA), with the anhydrides grafted to natural rubber in toluene using benzoyl peroxide as an initiator. Variations of monomer content, initiator content, temperature and reaction time of the grafting copolymerization were investigated. The maximum degrees of grafting were 1.06% for NR-g-CCA, 4.66% for NR-g-ICA, and 5.03% for NR-g-MA, reached using 10 phr citraconic anhydride, 10 phr of itaconic anhydride, or 8 phr of maleic anhydride, 3 phr benzoyl peroxide, at 85, 80 and 80°C for 2, 2 and 3 hrs, respectively. Solvent-based wood adhesives were formulated from these copolymers with various contents of wood resin in the range 10-40 phr. The maximal 289 N/in cleavage peel and 245.7 KPa shear strength for NR-g-MA (5.03% grafting) were obtained at 40 phr wood resin.

  11. Coating carbon nanotubes with polymer in supercritical carbon dioxide.

    PubMed

    Wang, Jiawei; Khlobystov, Andrei N; Wang, Wenxin; Howdle, Steven M; Poliakoff, Martyn

    2006-04-21

    A facile and efficient method has been developed for coating MWNTs with solvent resistant polymer in scCO2, which permits the selective deposition of high molecular weight fluorinated graft poly(methyl vinyl ether-alt-maleic anhydride) polymer onto MWNTs in scCO2 under 100-170 bar at 40 degrees C and forms quasi one-dimensional nanostructures with conducting cores and insulating surfaces.

  12. Diastereoselective Synthesis of γ- and δ-Lactams from Imines and Sulfone-Substituted Anhydrides

    PubMed Central

    2015-01-01

    Sulfone-substituted γ- and δ-lactams have been prepared in a single step with high diastereoselectivity. Sulfonylglutaric anhydrides produce intermediates that readily decarboxylate to provide δ-lactams with high diastereoselectivity. Substituents at the 3- or 4-position of the glutaric anhydride induce high levels of stereocontrol. Sulfonylsuccinic anhydrides produce intermediate carboxylic acids that can be trapped as methyl esters or allowed to decarboxylate under mild conditions. This method has been applied to a short synthesis of the pyrrolizidine alkaloid (±)-isoretronecanol. PMID:24552208

  13. Method of Preparing Polymers with Low Melt Viscosity

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (Inventor)

    2001-01-01

    This invention is an improvement in standard polymerizations procedures, i.e., addition-type and step-growth type polymerizations, wherein monomers are reacted to form a growing polymer chain. The improvement includes employing an effective amount of a trifunctional monomer (such as a trifunctional amine anhydride, or phenol) in the polymerization procedure to form a mixture of polymeric materials consisting of branced polymers, star-shaped polymers, and linear polymers. This mixture of polymeric materials has a lower melt temperature and a lower melt viscosity than corresponding linear polymeric materials of equivalent molecular weight.

  14. Fire and heat resistant laminating resins based on maleimido substituted aromatic cyclotriphosphazene polymer

    NASA Technical Reports Server (NTRS)

    Kumar, Devendra (Inventor); Fohlen, George M. (Inventor); Parker, John A. (Inventor)

    1987-01-01

    4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g., hexakis amino or trisaminophenoxy trisphenoxy cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics.

  15. 21 CFR 872.3500 - Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. 872.3500 Section 872.3500...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. (a) Identification... adhesive is a device composed of polyvinylmethylether maleic anhydride, acid copolymer,...

  16. 21 CFR 872.3500 - Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. 872.3500 Section 872.3500...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. (a) Identification. Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium (NACMC)...

  17. 21 CFR 872.3500 - Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. 872.3500 Section 872.3500...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. (a) Identification. Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium (NACMC)...

  18. 21 CFR 872.3500 - Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. 872.3500 Section 872.3500...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. (a) Identification. Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium (NACMC)...

  19. Highly efficient peptide formation from N-acetylaminoacyl-AMP anhydride and free amino acid

    NASA Technical Reports Server (NTRS)

    Mullins, D. W., Jr.; Lacey, J. C., Jr.

    1983-01-01

    The kinetics of formation of the N-blocked dipeptide, N-acetylglycylglycine, from N-acetylglycyl adenylate anhydride and glycine in aqueous solution at 25 C, and at various PH's are reported. The reaction is of interest in that over a physiologically relevant pH range (6-8), peptide synthesis proceeds more rapidly than hydrolysis, even at those pH's at which this compound becomes increasingly susceptible to base-catalyzed hydrolysis. Under similar conditions, the corresponding unblocked aminoacyl adenylate anhydrides are considerably more unstable, and undergo appreciable hydrlysis in the presence of free amino acid. Because N-blocked aminoacyl adenylate anhydrides serve as model compounds of peptidyl adenylate anhydrides, these results suggest that primitive amino acid polymerization systems may have operated by cyclic reactivation of the peptidyl carboxyl group, rather than that of the incoming amino acid.

  20. 21 CFR 872.3500 - Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. 872.3500 Section 872.3500...), acid copolymer, and carboxymethylcellulose sodium (NACMC) denture adhesive. (a) Identification. Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium (NACMC)...

  1. Low molecular weight chemicals, hypersensitivity, and direct toxicity: the acid anhydrides.

    PubMed Central

    Venables, K M

    1989-01-01

    The acid anhydrides are a group of reactive chemicals used widely in alkyd and epoxy resins. The major hazards to health are mucosal and skin irritation and sensitisation of the respiratory tract. Most occupational asthma caused by acid anhydrides appears to be immunologically mediated. Immunological mechanisms have been proposed to explain an influenza-like syndrome and pulmonary haemorrhage, but direct toxicity may also be important in the aetiology of these conditions. PMID:2653411

  2. Chirally selective, intramolecular interaction observed in an aminoacyl adenylate anhydride

    NASA Technical Reports Server (NTRS)

    Lacey, J. C., Jr.; Hall, L. M.; Mullins, D. W., Jr.; Watkins, C. L.

    1985-01-01

    The interaction between amino acids and nucleotide bases is studied. The proton NMR spectrum of N-acetylphenylalanyl-AMP-anhydride is analyzed H8 and H2 signals, two upfield signals of equal size, and five phenylalanine ring proton signals are observed in the spectrum; the upfield movement of the proton and the racemization of the N-acetyl L-phenylalanine material are examined. The differences in the position of the signals due to the diastereoisomers are investigated. The separation of the D and L amino acyl adenylates using HPLC is described. H-1 NMR spectra of the isomers are examined in order to determine which isomer displays the strongest interaction between the phenyl ring and the adenine ring. The spectra reveal that the L isomer shows the highest upfield change of both H8 and H2 signals. It is noted that the phenyl ring lies over C2 of the adenine ring with the phenyl meta and para protons extended past the adenine ring and the phenyl ortho protons.

  3. Convergence of Biological Nitration and Nitrosation via Symmetrical Nitrous Anhydride

    PubMed Central

    Vitturi, Dario A.; Minarrieta, Lucia; Salvatore, Sonia R.; Postlethwait, Edward M.; Fazzari, Marco; Ferrer-Sueta, Gerardo; Lancaster, Jack R.; Freeman, Bruce A.; Schopfer, Francisco J.

    2015-01-01

    Current perspective holds that the generation of secondary signaling mediators from nitrite (NO2−) requires acidification to nitrous acid (HNO2) or metal catalysis. Herein, the use of stable isotope-labeled NO2− and LC-MS/MS analysis of products revealed that NO2− also participates in fatty acid nitration and thiol S-nitrosation at neutral pH. These reactions occur in the absence of metal centers and are stimulated by nitric oxide (•NO) autoxidation via symmetrical dinitrogen trioxide (nitrous anhydride, symN2O3) formation. While theoretical models have predicted physiological symN2O3 formation, its generation is now demonstrated in aqueous reaction systems, cell models and in viv, with the concerted reactions of •NO and NO2− shown to be critical for symN2O3 formation. These results reveal new mechanisms underlying the NO2− propagation of •NO signaling and the regulation of both biomolecule function and signaling network activity via NO2−-dependent nitrosation and nitration reactions. PMID:26006011

  4. Hydrolytic properties of phenylalanyl- and N-acetylphenylalanyl adenylate anhydrides

    NASA Technical Reports Server (NTRS)

    Lacey, J. C., Jr.; Mullins, D. W., Jr.; Senaratne, N.

    1984-01-01

    The hydrolysis of phenylalynyl- and N-acetylephenylalanyl adenylate anhydrides (AcPhe-AMP) is studied experimentally using a new spectrophotometric method. The hydrolysis process was analyzed at low concentrations (0.0001 M), constant temperature of 25 C, constant buffer concentration (0.05 M), and as a function of pH. It is found that while Phe-AMP is susceptible to attack by OH(-), AcPhe-AMP is susceptible to acid decomposition as well. At a pH of 4 to 8, Phe-AMP hydolyzes faster than AcPhe-AMP, but at pH less than four or greater than eight, the blocked form hydrolyzes faster. Both forms are attacked by H2O at the same rate. The rate laws for the various hydrolytic mechanisms and the activation energies for the hydrolyses at pH 7.1 are given in a table, and the possible relevance of the findings to the origin and evolution of the process of protein synthesis is discussed.

  5. Allergy to methyltetrahydrophthalic anhydride in epoxy resin workers.

    PubMed Central

    Nielsen, J; Welinder, H; Horstmann, V; Skerfving, S

    1992-01-01

    One hundred and forty four current and 26 former workers in a plant producing barrels for rocket guns from an epoxy resin containing methyltetrahydrophthalic anhydride (MTHPA; time weighted average air concentration up to 150 micrograms/m3) were studied. They showed higher frequencies of work related symptoms from the eyes (31 v 0%; p < 0.001), nose (53 v 9%; p < 0.001), pharynx (26 v 6%; p < 0.01), and asthma (11 v 0%; p < 0.05) than 33 controls. Also they had higher rates of positive skin prick test to a conjugate of MTHPA and human serum albumin (16 v 0%; p < 0.01), and more had specific IgE and IgG serum antibodies (18 v 0%; p < 0.01 and 12 v 0%; p < 0.05 respectively). There were statistically significant exposure-response relations between exposure and symptoms from eyes and upper airways, dry cough, positive skin prick test, and specific IgE and IgG antibodies. There was a non-significant difference in reaction to metacholine between exposed workers and non-smoking controls. In workers with and without specific IgE antibodies, differences existed in frequency of nasal secretion (54 v 23%; p < 0.05) and dry cough (38 v 12%; p < 0.05). Workers with specific IgG had more dry cough (38 v 12%; p < 0.05), but less symptoms of non-specific bronchial hyperreactivity (0 v 26%; p < 0.05). Atopic workers sneezed more than non-atopic workers (65 v 30%; p < 0.01). In a prospective study five sensitised workers who left the factory became less reactive to metacholine, and became symptom free. In 41 workers who stayed, there was no improvement, despite a 10-fold reduction in exposure. The results show the extreme sensitising properties of MTHPA. PMID:1463677

  6. Crystal structure of 2,3-di-methyl-maleic anhydride: continuous chains of electrostatic attraction.

    PubMed

    Wiscons, Ren A; Zeller, Matthias; Rowsell, Jesse L C

    2015-08-01

    In the crystal structure of 2,3-di-methyl-maleic anhydride, C6H6O3, the closest non-bonding inter-molecular distances, between the carbonyl C and O atoms of neighboring mol-ecules, were measured as 2.9054 (11) and 3.0509 (11) Å, which are well below the sum of the van der Waals radii for these atoms. These close contacts, as well as packing motifs similar to that of the title compound, were also found in the crystal structure of maleic anhydride itself and other 2,3-disubstituted maleic anhydrides. Computational modeling suggests that this close contact is caused by strong electrostatic inter-actions between the carbonyl C and O atoms.

  7. Solvothermal process for grafting maleic anhydride onto poly(ethylene 1-octene)

    NASA Astrophysics Data System (ADS)

    Liu, Qiaochu; Qi, Rongrong; Shen, Yanhan; Zhou, Chixing

    2007-11-01

    Solvothermal process was developed to graft maleic anhydride (MAH) onto poly(ethylene 1-octene) (POE). Fourier transform infrared spectra (FT-IR) and 1H NMR spectra confirmed that maleic anhydride was successfully grafted onto the POE. The influences of MAH content, initiator concentration, POE concentration, reaction temperature, reaction time and solvents on the graft copolymerization were investigated through both of the grafting degree (GD) and gel content (GC). The results demonstrated that high grafting degree (up to 10.85%) could be obtained while the gel content was still low. Further studies revealed that POE-g-MAH could also be achieved in poor solvents of POE through this method.

  8. Synthesis of mixed acid anhydrides from methane and carbon dioxide in acid solvents.

    PubMed

    Zerella, Mark; Mukhopadhyay, Sudip; Bell, Alexis T

    2003-09-04

    [reaction: see text] The reaction of CH(4) with CO(2) has been performed in anhydrous acids using VO(acac)(2) and K(2)S(2)O(8) as promoters. NMR analysis establishes that the primary product is a mixed anhydride of acetic acid and the acid solvent. In sulfuric acid, the overall reaction is CH(4) + CO(2) + SO(3) --> CH(3)C(O)-O-SO(3)H. Hydrolysis of the mixed anhydride produces acetic acid and the solvent acid. When trifluoroacetic acid is the solvent, acetic acid is primarily formed via the reaction CH(4) + CF(3)COOH --> CH(3)COOH + CHF(3).

  9. In vitro release of clomipramine HCl and buprenorphine HCl from poly adipic anhydride (PAA) and poly trimethylene carbonate (PTMC) blends.

    PubMed

    Dinarvand, Rassoul; Alimorad, Mohammed Massoud; Amanlou, Massoud; Akbari, Hamid

    2005-10-01

    Controlled drug-delivery technology is concerned with the systematic release of a pharmaceutical agent to maintain a therapeutic level of the drug in the body for modulated and/or prolonged periods of time. This may be achieved by incorporating the therapeutic agent into a degradable polymer vehicle, which releases the agent continuously as the matrix erodes. In this study, poly trimethylene carbonate (PTMC), an aliphatic polycarbonate, and poly adipic anhydride (PAA), an aliphatic polyanhydride, were synthesized via melt condensation and ring-opening polymerization of trimethylene carbonate and adipic acid, respectively. The release of clomipramine HCl and buprenorphine HCl from discs prepared with the use of PTMC-PAA blends in phosphate buffer (pH 7.4) are also described. Clomipramine HCl and buprenorphine HCl were both used as hydrophilic drug models. Theoretical treatment of the data with the Peppas model revealed that release of clomipramine HCl (5%) in devices containing 70% PTMC or more followed a Fickian diffusion model. However, the releases of buprenorphine HCl (5%) in the same devices were anomalous. For devices containing 50% and more PAA, surface erosion may play a significant role in the release of both molecules.

  10. Photothermal and morphological characterization of PLA/PCL polymer blends

    NASA Astrophysics Data System (ADS)

    Correa-Pacheco, Z. N.; Jiménez-Pérez, J. L.; Sabino, M. A.; Cruz-Orea, A.; Loaiza, M.

    2015-09-01

    Nowadays, some synthetic polymers have been replaced by biodegradable polymers in order to avoid environmental contamination. Among these biodegradables polymers, aliphatic polyesters such as polylactic acid (PLA) and polycaprolactone (PCL) have been widely used. In the present study, solvent-casting films of PLA, PCL and polymer blends with and without compatibilizer (PLA grafted with maleic anhydride) were prepared. The thermal diffusivity ( α) of each sample was obtained by using the open photoacoustic cell technique. Morphology and thermal properties were determined by using scanning electron microscopy, transmission electron microscopy and differential scanning calorimetry (DSC), respectively. The blends showed lower thermal diffusivity compared to pure polymers. However, when the compatibilizer was used, the highest value of thermal diffusivity was obtained. Also, cold crystallization with the highest value of enthalpy of fusion was observed for the compatibilized sample, which was revealed by DSC. To our knowledge, this is the first time that the thermal diffusivity of these biodegradable polymer blends is reported.

  11. Enhancement of mechanical and thermal properties of oil palm empty fruit bunch fiber poly(butylene adipate-co-terephtalate) biocomposites by matrix esterification using succinic anhydride.

    PubMed

    Siyamak, Samira; Ibrahim, Nor Azowa; Abdolmohammadi, Sanaz; Yunus, Wan Md Zin Bin Wan; Rahman, Mohamad Zaki Ab

    2012-02-16

    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.

  12. Metal phthalocyanine intermediates for the preparation of polymers

    NASA Technical Reports Server (NTRS)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A.

    1985-01-01

    Metal 4, 4', 4"",-tetracarboxylic phthalocyanines (MPTC) are prepared by reaction of trimellitic anhydride, a salt or hydroxide of the desired metal (or the metal in powdered form), urea and a catalyst. A purer form of MPTC is prepared than heretofore. These tetracarboxylic acids are then polymerized by heat to sheet polymers which have superior heat and oxidation resistance. The metal is preferably a divalent metal having an atomic radius close to 1.35A.

  13. Nano-encapsulation of coenzyme Q10 using octenyl succinic anhydride modified starch

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Octenyl succinic anhydride modified starch (OSA-ST) was used to encapsulate Coenzyme Q10 (CoQ10). CoQ10 was dissolved in rice bran oil (RBO), and incorporated into an aqueous OSA-ST solution. High pressure homogenization (HPH) of the mixture was conducted at 170 MPa for 5-6 cycles. The resulting ...

  14. Technical note: Tall oil fatty acid anhydrides as corrosion inhibitor intermediates

    SciTech Connect

    Fischer, E.R.; Parker, J.E. III

    1997-01-01

    Anhydrides derived from tall oil fatty acids offer enhanced corrosion inhibition properties compared to traditional dimer/trimer acids. The chemistry of this intermediate, its use in corrosion inhibition for downhole applications, and the synthesis of novel oil- and water-soluble derivatives were studied.

  15. A green synthesis of isatoic anhydrides from isatins with urea-hydrogen peroxide complex and ultrasound.

    PubMed

    Deligeorgiev, Todor; Vasilev, Aleksey; Vaquero, Juan J; Alvarez-Builla, Julio

    2007-07-01

    The oxidation of isatins at room temperature, using the cheap and environmentally friendly urea-hydrogen peroxide complex and ultrasonic irradiation, has been investigated. The ultrasonic irradiation dramatically reduces the reaction time. With easy and reproducible reaction procedures, different isatoic anhydrides were obtained in excellent yield and with high purity.

  16. SELECTIVE HYDROGENATION OF ANHYDRIDES TO LACTONES UNDER SUPERCRITICAL CARBON DIOXIDE MEDIUM

    EPA Science Inventory

    Selective Hydrogenation of Anhydrides to Lactones Under Supercritical Carbon Dioxide Medium

    Endalkachew Sahle-Demessie Unnikrishnan R Pillai
    U.S. EPA , 26 W. Martin Luther King Dr. Cincinnati, OH 45268 Phone: 513-569-7739
    Fax: 513-569-7677
    Abstract:
    Hydrogenat...

  17. TRIMELLITIC ANHYDRIDE-INDUCED EOSINOPHILLA IN A MOUSE MODEL OF OCCUPATIONAL ASTHMA

    EPA Science Inventory

    Trimellitic anhydride (TMA) is a low molecular weight chemical known to cause occupational asthma. The present study was designed to determine if TMA could elicit eosinophil infiltration into the lung of a sensitized mouse similarly to previous studies with the protein allergen ...

  18. Formation and stability of Vitamin E enriched nanoemulsions stabilized by Octenyl Succinic Anhydride modified starch

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vitamin E (VE) is highly susceptible to autoxidation; therefore, it requires systems to encapsulate and protect it from autoxidation.In this study,we developed VE delivery systems, which were stabilized by Capsul® (MS), a starch modified with octenyl succinic anhydride. Influences of interfacial ten...

  19. Deposition of antibacterial of poly(1,3-bis-(p-carboxyphenoxy propane)-co-(sebacic anhydride)) 20:80/gentamicin sulfate composite coatings by MAPLE

    NASA Astrophysics Data System (ADS)

    Cristescu, R.; Popescu, C.; Socol, G.; Visan, A.; Mihailescu, I. N.; Gittard, S. D.; Miller, P. R.; Martin, T. N.; Narayan, R. J.; Andronie, A.; Stamatin, I.; Chrisey, D. B.

    2011-04-01

    We report on thin film deposition of poly(1,3-bis-(p-carboxyphenoxy propane)-co-sebacic anhydride)) 20:80 thin films containing several gentamicin concentrations by matrix assisted pulsed laser evaporation (MAPLE). A pulsed KrF* excimer laser was used to deposit the polymer-drug composite thin films. Release of gentamicin from these MAPLE-deposited polymer conjugate structures was assessed. Fourier transform infrared spectroscopy was used to demonstrate that the functional groups of the MAPLE-transferred materials were not changed by the deposition process nor were new functional groups formed. Scanning electron microscopy confirmed that MAPLE may be used to fabricate thin films of good morphological quality. The activity of gentamicin-doped films against Escherichia coli and Staphylococcus aureus bacteria was demonstrated using disk diffusion and antibacterial drop test. Our studies indicate that deposition of polymer-drug composite thin films prepared by MAPLE is a suitable technique for performing controlled drug delivery. Antimicrobial thin film coatings have several medical applications, including use for indwelling catheters and implanted medical devices.

  20. Microwave synthesis and thermal properties of polyacrylate derivatives containing itaconic anhydride moieties

    PubMed Central

    2012-01-01

    Background Microwave irradiation as an alternative heat source is now a well-known method in synthetic chemistry. Microwave heating has emerged as a powerful technique to promote a variety of chemical reactions, offering reduced pollution, low cost and offer high yields together with simplicity in processing and handling. On the other hand, copolymers containing both hydrophilic and hydrophobic segments are drawing considerable attention because of their possible use in biological systems. Various copolymer compositions can produce a very large number of different arrangements, producing materials of varying chemical and physical properties. Thus, the hydrophilicity of copolymers can be modified by changing the amount of incorporated itaconic anhydride. Results A series of methyl methacrylate (MMA) and acrylamide (AA) copolymers containing itaconic anhydride (ITA) were synthesized by microwave irradiation employing a multimode reactor (Synthos 3000 Aton Paar, GmbH, 1400 W maximum magnetron) as well as conventional method. The thermal properties of the copolymers were evaluated by different techniques. Structure-thermal property correlation based on changing the itaconic anhydride ratio was demonstrated. Results revealed that the incorporation of itaconic anhydride into the polymeric backbone of all series affect the thermal stability of copolymers. In addition, the use of the microwave method offers high molecular weight copolymers which lead eventually to an increase in thermal stability. Conclusions Microwave irradiation method showed advantages for the produced copolymers compared to that prepared by conventional method, where it can offer a copolymer in short time, high yield, more pure compounds and more thermally stable copolymers, rather than conventional method. Also, microwave irradiation method gives higher molecular weight due to prevention of the chain transfer. Moreover, as the itaconic anhydride content increases the thermal stability and Tg increase

  1. [The working environment control of anhydride hardeners from an epoxy resin system].

    PubMed

    Matsumoto, Naomi; Yokota, Kozo; Johyama, Yasushi; Takakura, Toshiyuki

    2003-07-01

    Epoxy resins are widely used in adhesives, coatings, materials for molds and composites, and encapsulation. Acid anhydrides such as methyltetrahydrophthalic anhydride are being used as curing agents for epoxy resins. The anhydride hardeners are well-known industrial inhalant allergens, inducing predominantly type I allergies. In the electronic components industry, these substances have been consumed in large quantities. Therefore, safe use in the industry demands control of the levels of exposure causing allergic diseases in the workshop. We conducted a prospective survey of two electronics plants to clarify how to control the atmospheric level of the anhydrides in the work environment. Measurements of the levels of the anhydrides in air started according to the Working Environment Measurement Standards (Ministry of Labour Notification No. 46, 1976) in April 2000, along with improvements in the work environment. A value of 40 micrograms/m3 was adopted as the administrative control level to judge the propriety of the working environment control. A total of 2 unit work areas in both plants belonged to Control Class III. The exposure originated from manual loading, casting, uncured hot resins, and leaks in an impregnating-machine or curing ovens. In order to achieve the working environment control, complete enclosure of the source, installation of local exhaust ventilation, and improvement or maintenance of the local exhaust ventilation system were performed on the basis of the results of the working environment measurement, with the result that the work environment was improved (Control Class I). It became evident that these measures were effective just like other noxious substances.

  2. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  3. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  4. PLA branching with anhydrides and tri-functional aziridine

    NASA Astrophysics Data System (ADS)

    Gu, Liangliang; Xu, Yuewen; Naredla, Rajasekhar; Hoye, Thomas; Macosko, Christopher

    Branched PLA was prepared by melt blending with tri-functional aziridine (T-Az) and pyromellitic dianhydride (PMDA). 1HNMR, gel permeation chromatography (GPC) and rheology were used to characterize the topological structures of branched PLA. Fast reaction between PLA carboxyl end group and T-Az resulted in 3-arm stars and increased the molecular weight. However, the 3-arm stars did not show strain hardening behavior under extensional flow. After modifying PLA hydroxyl end group with PMDA, PLA can react with T-Az on both chain ends and form long chain branched structure, which showed strain hardening in extension. It was found that that only 10% of the PLA hydroxyl end groups reacted with PMDA. This work is supported by Center for Sustainable Polymers.

  5. Contributions of polymers to bentonite and saponite fluids

    SciTech Connect

    Guven, N.; Carney, L.L.; Panfil, D.J. . Dept. of Geosciences)

    1991-02-01

    Polymers have been used in drilling fluids for many years. However, the confusion surrounding the use of polymers in the oil field has severely limited their effectiveness. Many oilfield workers simply put all polymers in the same category without regard to the many differences that exist among them. Homopolymers and copolymers of acrylic acid and a copolymer of styrene and maleic anhydride are found to have profound effects on the rheological and filtration properties of clay-based fluids up to 300{degrees}F. These contributions of the polymers are greatly diminished when the clay/polymer fluids were autoclaved at 400{degrees}F. Thus, the effects of these polymers are expected to be negligible at and above 400{degrees}F. Homo- and co-polymers of acrylic acid with molecular weights below 5000 almost eliminate the anomalous viscosity rise of the bentonite fluids at temperatures between 250--450{degrees}F. A homopolymer of acrylic acid with a molecular weight of 60,000 and a co-polymer of styrene and maleic anhydride with very high molecular weight further enhances the anomalous viscosity rise of the bentonite fluid. The original viscosity profile of the saponite fluid is characterized with a high initial viscosity up to 200{degrees}F which is followed by a steep thinning at higher temperatures. The addition of homo- and co-polymer of acrylic acid causes a complete reversal in the fluid viscosity. They become thin at lower temperatures (up to 250{degrees}F) and experience a sudden viscosity rise at higher temperatures. All the above polymers greatly improve the filtration losses of the fluids at room temperatures as indicated by the API test. The filtration tests at high pressure and high temperatures were inconclusive due to the frequent blow-outs that occur during the tests.

  6. Ruthenium-catalyzed decarbonylative addition reaction of anhydrides with alkynes: a facile synthesis of isocoumarins and α-pyrones.

    PubMed

    Prakash, Rashmi; Shekarrao, Kommuri; Gogoi, Sanjib; Boruah, Romesh C

    2015-06-21

    A novel ruthenium catalyzed straightforward and efficient synthesis of isocoumarin and α-pyrone derivatives has been accomplished by the decarbonylative addition reaction of anhydrides with alkynes under thermal conditions.

  7. Preparation and Mechanical Properties of Chitosan-graft Maleic Anhydride Reinforced with Montmorillonite

    NASA Astrophysics Data System (ADS)

    Fajrin, A.; Sari, L. A.; Rahmawati, N.; Saputra, O. A.; Suryanti, V.

    2017-02-01

    The research aims to develop biodegradable composites as bio-based plastics from chitosan. The composites were prepared via solution casting method by introducing the maleic anhydride (MAH) as grafting agent and montmorillonite (MMt) as reinforcement. The grafting process of chitosan was conducted by varying concentrations of MAH which were 10, 20, and 30% w/w. It was observed that the chitosan-graft-maleic anhydride (Cs-g-MAH) containing 10% w/w of MAH increased its tensile strength by 70%. Reinforcement material was added to the Cs-g-MAH by varying MMt concentrations, e.g. 3, 6, 9 and 12% w/w. It was noted that the presence of 9% w/w of MMt in the Cs-g-MAH gave the best mechanical properties of the Cs-g-MAH/MMt composite.

  8. Enhanced activity of immobilized dimethylmaleic anhydride-protected poly- and monoclonal antibodies.

    PubMed

    Hadas, E; Koppel, R; Schwartz, F; Raviv, O; Fleminger, G

    1990-06-27

    The effect of reversible protection of the free amino groups of poly- and monoclonal antibodies by dimethylmaleic anhydride on their binding activity following immobilization onto various carriers was studied. The treatment with dimethylmaleic anhydride resulted in a 1.6-1.8-fold increase in the activity of immobilized goat anti-mouse immunoglobulin antibody immobilized onto different epoxy containing carriers and a 3-10.7-fold increase in the activity of immobilized monoclonal antibodies specific for carboxypeptidase A. The increase in activity was most pronounced at low antigen to carrier loads and over a wide range of modifier to protein ratios. The application of reversible protection of antibodies may permit the development of highly active immobilized antibody preparations for use in immunoaffinity purification.

  9. Formic Sulfuric Anhydride: a New Chemical Species with Possible Implications for Atmospheric Aerosol

    NASA Astrophysics Data System (ADS)

    Mackenzie, Becca; Dewberry, Chris; Leopold, Ken

    2015-06-01

    Aerosols are important players in the Earth's atmosphere, affecting climate, cloud formation, and human health. In this work, we report the discovery of a previously unknown molecule, formic sulfuric anhydride (FSA), that may influence the formation and composition of atmospheric aerosol particles. Five isotopologues of FSA have been observed by microwave spectroscopy and further characterized using DFT calculations. The system has dipole moment components along all three inertial axes, and indeed a, b, and c-type transitions have been observed. A π2 + π2 + σ2 cycloaddition reaction between SO3 and HCOOH is proposed as a possible mechanism for the formation of FSA and calculations indicate that the transformation is effectively barrierless. Facile formation of the anhydride followed by hydrolysis in small water-containing clusters or liquid droplets may provide a mechanism of incorporating volatile organics into atmospheric aerosol. We suggest that FSA and its derivatives be considered in future atmospheric and climate models.

  10. Electron paramagnetic resonance and FT-IR spectroscopic studies of glycine anhydride and betaine hydrochloride

    NASA Astrophysics Data System (ADS)

    Halim Başkan, M.; Kartal, Zeki; Aydın, Murat

    2015-12-01

    Gamma irradiated powders of glycine anhydride and betaine hydrochloride have been investigated at room temperature by electron paramagnetic resonance (EPR). In these compounds, the observed paramagnetic species were attributed to the R1 and R2 radicals, respectively. It was determined that the free electron interacted with environmental protons and 14N nucleus in both radicals. The EPR spectra of gamma irradiated powder samples remained unchanged at room temperature for two weeks after irradiation. Also, the Fourier Transform Infrared (FT-IR), FT-Raman and thermal analyses of both compounds were investigated. The functional groups in the molecular structures of glycine anhydride and betaine hydrochloride were identified by vibrational spectroscopies (FT-IR and FT-Raman).

  11. Wheat Gluten Blends with Maleic Anhydride-Functionalized Polyacrylate Cross-Linkers for Improved Properties.

    PubMed

    Diao, Cheng; Xia, Hongwei; Parnas, Richard S

    2015-10-14

    A family of polyacrylate-based cross-linkers was synthesized to maximize the toughness of high Tg, high modulus wheat gluten blends in the glassy state. Mechanical testing and damping measurements were conducted to provide an example where the work of fracture and strength of the blend substantially exceeds polystyrene while maintaining flexure stiffness in excess of 3 GPa. The new rubbery cross-linkers, polymethyl acrylate-co-maleic anhydride and polyethyl acrylate-co-maleic anhydride, improve WG mechanical properties and reduce water absorption simultaneously. MDSC, FTIR, HPLC, and NMR data confirmed the cross-linking reaction with wheat gluten. Flexural, DMA, and water absorption testing were carried out to characterize the property improvements. DMA was conducted to investigate the relationship between energy damping and mechanical property improvement. If the cross-linker damping temperature is close to the testing temperature, the entire sample exhibits high damping, toughness, and strength.

  12. Effect of impurities in polybutene on the quality of alkenylsuccinic anhydrides

    SciTech Connect

    Yarmolyuk, B.M.; Pustovit, V.E.; Bereza, L.I.; Antonov, V.N.; Shablii, V.I.; Vititneva, L.A.

    1984-03-01

    Synthesis of alkenylsuccini anhydrides (ASAs) was carried out in thermostable ampules at 230/sup 0/C in the course of 12 hours at an MA:PB molar ratio of 1.3:1 in a medium of prepurified petroleum xylene (30%). Freshly distilled maleic anhydride and industrial specimens of polybutene were used in the experiments. It was established that the main impurities which are formed in the production of polybutene and in its processing are ions of sodium, peroxide compounds and products of decomposition of the polymerization catalyst. The concentration of sodium ion was determined by an atomic adsorption method on an A-3000 instrument, the concentration of peroxides was determined by iodometry (3), and the concentration of catalyst decomposition products was determined from the amount of mechanical impurities.

  13. Stereocontrol in Asymmetric γ-Lactam Syntheses from Imines and Cyanosuccinic Anhydrides

    PubMed Central

    Pattawong, Ommidala; Tan, Darlene Q.; Fettinger, James C.; Shaw, Jared T.; Cheong, Paul Ha-Yeon

    2014-01-01

    Computations (SCS-MP2//B3LYP) reveal that the asymmetric synthesis of highly substituted γ-lactams with three stereogenic centers, including one quaternary center, proceeds through a Mannich reaction between the enol form of the anhydride and the E-imine, followed by a transannular acylation. This new mechanistic picture accounts for both the observed reactivity and stereoselectivity. CH-O and hydrogen bonding interactions in the Mannich step and torsional steering effects in the acylation step are responsible for stereocontrol. It is demonstrated that this new mechanistic picture applies to the related reactions of homophthalic anhydrides with imines and presents new vistas for the design of a new reaction to access complex molecular architectures. PMID:24070216

  14. On the Formation of Maleic Anhydride on a Vanadyl Pyrophosphate Surface: A Theoretical Study of the Mechanism

    DTIC Science & Technology

    1990-05-25

    synthesis of maleic anhydride from n - butane over a vanadium phosphorous oxide surface in the presence of molecular oxygen [equation ( 1 )]. 7 / • 3.5 0 2 (g...active vanadium phosphorous oxide phase in the oxidation of n - butane has been disputed in the literature. 7 0, 0 Generally, it is agreed that the presence...mechanism for the selective oxidation of n - butane to maleic anhydride. Satsuma et al. have described the surface structure in terms of the number of

  15. Palladium-catalyzed regioselective carbonylation of C-H bonds of N-alkyl anilines for synthesis of isatoic anhydrides.

    PubMed

    Guan, Zheng-Hui; Chen, Ming; Ren, Zhi-Hui

    2012-10-24

    A Pd-catalyzed regioselective C-H bond carbonylation of N-alkyl anilines for the synthesis of isatoic anhydrides has been developed. The key Pd-catalyst intermediate has been isolated and characterized. This novel Pd-catalyzed carbonylation reaction tolerates a wide range of functional groups and is a reliable method for the rapid elaboration of readily available N-alkyl anilines into a variety of substituted isatoic anhydrides under mild conditions.

  16. 1,3-Dipolar cycloaddition-decarboxylation reactions of an azomethine ylide with isatoic anhydrides: formation of novel benzodiazepinones.

    PubMed

    D'Souza, Asha M; Spiccia, Nadia; Basutto, Jose; Jokisz, Pawel; Wong, Leon S-M; Meyer, Adam G; Holmes, Andrew B; White, Jonathan M; Ryan, John H

    2011-02-04

    A nonstabilized azomethine ylide reacts with a wide range of substituted isatoic anhydrides to afford novel 1,3-benzodiazepin-5-one derivatives, which are generally isolated in high yield. The transformations involve 1,3-dipolar cycloaddition reactions of the ylide with the anhydrides to give transient, and in a representative case spectroscopically observable, oxazolidine intermediates that undergo ring-opening-decarboxylation-ring-closing reaction cascades to yield the 1,3-benzodiazepin-5-one products.

  17. Palladium-catalyzed decarboxylative coupling of isatoic anhydrides with arylboronic acids.

    PubMed

    Lu, Wei; Chen, Jiuxi; Liu, Miaochang; Ding, Jinchang; Gao, Wenxia; Wu, Huayue

    2011-11-18

    The decarboxylative coupling of isatoic anhydrides with arylboronic acids was realized for the first time in the presence of Pd(2)(dba)(3) and DPEphos, achieving aryl o-aminobenzoates with yields ranging from moderate to good. The efficiency of this procedure was demonstrated by good compatibility with fluoro, chloro, bromo, nitro, cyano, trifluoromethyl, formacyl, acetyl, thienyl, and naphthyl groups. Preliminary mechanistic experiments using deuterium labeling showed that the oxygen atom was derived from dioxygen.

  18. Novel synthetic method for the preparation of amphiphilic hyaluronan by means of aliphatic aromatic anhydrides.

    PubMed

    Huerta-Angeles, Gloria; Bobek, Martin; Příkopová, Eva; Šmejkalová, Daniela; Velebný, Vladimír

    2014-10-13

    The present work describes a novel and efficient method of synthesis of amphiphilic hyaluronan (HA) by esterification with alkyl fatty acids. These derivatives were synthesized under mild aqueous and well controlled conditions using mixed aliphatic aromatic anhydrides. These anhydrides characterized by the general formula RCOOCOC6H2Cl3 can be easily prepared by the reaction of the corresponding fatty acid (R) with 2,4,6-trichlorobenzoyl chloride (TCBC) in the presence of triethylamine. The aliphatic aromatic anhydrides RCOOCOC6H2Cl3 then react with the polysaccharide and enable the synthesis of aliphatic acid esters of HA in good yields. No hydrolytic degradation of hyaluronic acid could be observed. Parameters controlling the degree of esterification were systematically studied. Fatty acids with different chain lengths can be introduced applying this methodology. The degree of substitution was decreasing with increasing length of hydrophobic chain. The reaction products were fully characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), SEC-MALLS and chromatographic analyses. Although the esterified HA products exhibited aggregation in solution as demonstrated by NMR, microscopy and rheology, they were still water-soluble.

  19. Study on oil absorbency of succinic anhydride modified banana cellulose in ionic liquid.

    PubMed

    Shang, Wenting; Sheng, Zhanwu; Shen, Yixiao; Ai, Binling; Zheng, Lili; Yang, Jingsong; Xu, Zhimin

    2016-05-05

    Banana cellulose contained number of hydrophilic hydroxyl groups which were succinylated to be hydrophobic groups with high oil affinity. Succinic anhydride was used to modify banana cellulose in 1-allyl-3-methylimidazolium chloride ionic liquid in this study. The modified banana cellulose had a high oil absorption capacity. The effects of reaction time, temperature, and molar ratio of succinic anhydride to anhydroglucose on the degree of substitution of modified banana cellulose were evaluated. The optimal reaction condition was at a ratio of succinic anhydride and anhydroglucose 6:1 (m:m), reaction time 60min and temperature 90°C. The maximum degree of acylation reaction reached to 0.37. The characterization analysis of the modified banana cellulose was performed using X-ray diffractometer, Fourier transform infrared spectrometer, scanning electron microscopy and thermogravimetry. The oil absorption capacity and kinetics of the modified banana cellulose were evaluated at the modified cellulose dose (0.025-0.3g), initial oil amount (5-30g), and temperature (15-35°C) conditions. The maximum oil absorption capacity was 32.12g/g at the condition of the cellulose dose (0.05g), initial oil amount (25g) and temperature (15°C). The kinetics of oil absorption of the cellulose followed a pseudo-second-order model. The results of this study demonstrated that the modified banana cellulose could be used as an efficient bio-sorbent for oil adsorption.

  20. Reevaluation of Tetrahydrophthalic Anhydride as an End Cap for Improved Oxidation Resistance in Addition Polyimides

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Frimer, Aryeh A.; Johnston, J. Christopher

    2003-01-01

    Several substituted 1,2,3,6-tetrahydrophthalic anhydride end caps - including the 3-phenyl, 3-methoxy, 3-trimethylsilyloxy, and 3,6-diphenyl analogs - were synthesized via the Diels-Alder condensation of the corresponding butadienes and maleic anhydride. These anhydrides, as well as the commercially available 3-hydro and 4-methyl analogs, were each ground together with methylenedianiline in a 2:1 ratio and heated gradually from 204 C to 371 C, with the thermolysis followed by NMR. Generally speaking, a transformation via monoimide to bisimide was observed in the lower temperature range, followed by competition between crosslinking and aromatization. We believe that this competition produces a substantial percentage of aromatic product, with the concomitant lowering of the relative amount of crosslinking and is responsible for improving both thermal oxidative stability of tetrahydrophthalic end capped polyimides and their substantial frangibility. The thermolysis of the tetrahydrophthalimides under inert atmosphere dramatically lowers the amount of aromatization hence, the mechanism for aromatization is an oxidative one.

  1. Sub-micronic capsules based on gelatin and poly(maleic anhydride-alt-vinyl acetate) obtained by interfacial condensation with potential biomedical applications.

    PubMed

    Iurea, Delia Mihaela; Peptu, Cătălina Anişoara; Chailan, Jean-François; Carriere, Pascal; Popa, Marcel

    2013-06-01

    New sub-micronic capsules based on a copolymer of maleic anhydride-alt-vinyl acetate and a natural polymer (gelatin) using an interfacial condensation method were obtained. Sub-micronic capsules were characterized by Fourier Transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) method, zeta-potential, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal properties were investigated by thermogravimetric analysis (TGA). According to some parameters of the synthesis reaction (polymer weight ratio, acetone/water ratio, surfactant concentration), the mean diameter of the sub-micronic capsules can be tuned from 200 to 760 nm. The sub-micronic capsules show a higher agglomeration tendency as the amount of gelatin in their composition increases. The swelling capacity in aqueous solutions is dependent on the composition and size of the sub-micronic capsules, decreasing with their diameter and gelatin composition. The drug loading and release capacity was studied using Penicillin G (sodium salt) (PG), and it has been proved that it is influenced by the sub-micronic capsules morphology induced by preparation parameters. Encapsulation and controlled release of small molecule were successfully carried out, demonstrating the potential biomedical applications of these new easily obtained sub-micronic capsules.

  2. Orientation and bonding of benzoic acid, phthalic anhydride and pyromellitic dianhydride on Cu(110)

    NASA Astrophysics Data System (ADS)

    Frederick, B. G.; Ashton, M. R.; Richardson, N. V.; Jones, T. S.

    1993-07-01

    The interaction of the polyimide precursor pyromellitic dianhydride (PMDA), and the related compounds benzoic acid and phthalic anhydride, with Cu(110) has been studied by high resolution electron energy loss spectroscopy (HREELS). For benzoic acid, deprotonation of the carboxylic acid group occurs on adsorption leading to the formation of a surface benzoate species (C 6H 5COO-). Bonding to the surface occurs through a carboxylate linkage via two equivalent oxygen atoms. The HREEL spectrum is characterised by an intense dipole active band, the symmetric OCO stretching vibration, at ˜ 1420 cm -1. The plane of the carboxylate group is aligned perpendicular to the surface as is the plane of the benzene ring. A similar species is found following exposure of Cu(110) to phthalic anhydride. The carboxylate linkage results from disruption of the anhydride ring with loss of the CO character (C 6H 4COO-). In the case of the dianhydride species PMDA, only one of the anhydride units is used in bonding to the surface; the second unit points away from the surface and is characterised by the symmetric anhydride stretch at 1255 cm -1 and weak OO stretching vibrations at ˜ 1850 cm -1. In both cases, changes in the intensity of some of the bands compared with benzoic acid suggest that the carboxylate group is tilted away from the surface normal due to an interaction between one of the carbons of the aromatic ring and the copper surface. This implies that the plane of the aromatic ring is now twisted out of the plane of the carboxylate group and, although still perpendicular to the surface, the axis is tilted to allow one of the β-carbon atoms to interact with the surface. In all cases, off-specular measurements at a primary electron energy of ˜ 8 eV are dominated by the intense CH stretching vibration. Measurements of the intensity of this mode, in the surface benzoate species, as a function of incident electron energy suggest that excitation of this mode occurs via

  3. Transparent lithiated polymer films for thermal neutron detection

    NASA Astrophysics Data System (ADS)

    Mabe, Andrew N.; Auxier, John D.; Urffer, Matthew J.; Penumadu, Dayakar; Schweitzer, George K.; Miller, Laurence F.

    2013-09-01

    Novel water-soluble 6Li loaded copolymer scintillation films have been designed and fabricated to detect thermal neutrons. Styrene and maleic anhydride were copolymerized to form an alternating copolymer, then the anhydride functionality was hydrolyzed using 6Li hydroxide. The resulting poly(styrene-co-lithium maleate) was mixed with salicylic acid as a fluor and cast as a thin film from water. The maximum 6Li loading obtained that resulted in a transparent film was 4.36% by mass (6Li to polymer). The optimum fluorescence output was obtained for 11.7% salicylic acid by mass, presumably in the form of lithium salicylate, resulting in an optimum film containing 3.85% by mass of 6Li. A facile and robust synthesis method, film fabrication protocol, photoluminescence results, and scintillation responses are reported herein.

  4. 40 CFR 721.3635 - Octadecanoic acid, ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-propanediol, phosphate, anhydride with silicic acid (H4SiO4). 721.3635 Section 721.3635 Protection of..., ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4). (a) Chemical substance and... with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4) (PMN P-96-1520; CAS No....

  5. 40 CFR 721.3635 - Octadecanoic acid, ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-propanediol, phosphate, anhydride with silicic acid (H4SiO4). 721.3635 Section 721.3635 Protection of..., ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4). (a) Chemical substance and... with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4) (PMN P-96-1520; CAS No....

  6. 40 CFR 721.3635 - Octadecanoic acid, ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-propanediol, phosphate, anhydride with silicic acid (H4SiO4). 721.3635 Section 721.3635 Protection of..., ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4). (a) Chemical substance and... with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4) (PMN P-96-1520; CAS No....

  7. Microgravity Polymers

    NASA Technical Reports Server (NTRS)

    1986-01-01

    A one-day, interactive workshop considering the effects of gravity on polymer materials science was held in Cleveland, Ohio, on May 9, 1985. Selected programmatic and technical issues were reviewed to introduce the field to workshop participants. Parallel discussions were conducted in three disciplinary working groups: polymer chemistry, polymer physics, and polymer engineering. This proceedings presents summaries of the workshop discussions and conclusions.

  8. Drawbacks in the use of unconventional hydrophobic anhydrides for histone derivatization in bottom-up proteomics PTM analysis

    PubMed Central

    Sidoli, Simone; Yuan, Zuo-Fei; Lin, Shu; Karch, Kelly; Wang, Xiaoshi; Bhanu, Natarajan; Arnaudo, Anna M.; Britton, Laura-Mae; Cao, Xing-Jun; Gonzales-Cope, Michelle; Han, Yumiao; Liu, Shichong; Molden, Rosalynn C.; Wein, Samuel; Afjehi-Sadat, Leila; Garcia, Benjamin A.

    2015-01-01

    Mass spectrometry (MS)-based proteomics has become the most utilized tool to characterize histone post-translational modifications (PTMs). Since histones are highly enriched in lysine and arginine residues, lysine derivatization has been developed to prevent the generation of short peptides (3-6 residues) during trypsin digestion. One of the most adopted protocols applies propionic anhydride for derivatization. However, the propionyl group is not sufficiently hydrophobic to fully retain the shortest histone peptides in reversed-phase liquid chromatography, and such procedure also hampers the discovery of natural propionylation events. In this work we tested 12 commercially available anhydrides, selected based on their safety and hydrophobicity. Performance was evaluated in terms of yield of the reaction, MS/MS fragmentation efficiency and drift in retention time by using the following samples: (i) a synthetic unmodified histone H3 tail, (ii) synthetic modified histone peptides and (iii) a histone extract from cell lysate. Results highlighted that 7 of the selected anhydrides increased peptide retention time as compared to propionic, and several anhydrides such as benzoic and valeric led to high MS/MS spectra quality. However, propionic anhydride derivatization still resulted in our opinion as the best protocol to achieve high MS sensitivity and more even ionization efficiency among the analyzed peptides. PMID:25641854

  9. Space charge behaviour in maleic anhydride grafted polyethylene/ethylene - vinyl - acetate copolymer laminates

    NASA Astrophysics Data System (ADS)

    Lee, Seung Hyung; Park, Jung Ki; Han, Jae Hong; Suh, Kwang S.

    1997-01-01

    Charge distributions in maleic anhydride (MAH) grafted polyethylene (g-PE)/ethylene - vinyl - acetate (EVA) copolymer laminates have been measured with materials of different composition. All laminates showed interfacial charge, the polarity and the magnitude of which are explained by interfacial polarization. It was found that the interfacial charge increased with the increase of MAH content in the g-PE, whereas it decreased with the increase of vinyl - acetate content in the EVA. This feature was attributed to the differences in electrical conductivity of the materials. Details of the experimental results are described.

  10. Perfluoroalkylation of Unactivated Alkenes with Acid Anhydrides as the Perfluoroalkyl Source.

    PubMed

    Kawamura, Shintaro; Sodeoka, Mikiko

    2016-07-18

    An efficient perfluoroalkylation of unactivated alkenes with perfluoro acid anhydrides was developed. Copper salts play a crucial role as a catalyst to achieve allylic perfluoroalkylation with the in situ generated bis(perfluoroacyl) peroxides. Furthermore, carboperfluoroalkylation of alkene bearing an aromatic ring at an appropriate position on the carbon side chain was found to proceed under metal-free conditions to afford carbocycles or heterocycles bearing a perfluoroalkyl group. This method, which makes use of readily available perfluoroalkyl sources, offers a convenient and powerful tool for introducing a perfluoroalkyl group onto an sp(3) carbon to construct synthetically useful skeletons.

  11. Electrospun mats from styrene/maleic anhydride copolymers: modification with amines and assessment of antimicrobial activity.

    PubMed

    Ignatova, Milena; Stoilova, Olya; Manolova, Nevena; Markova, Nadya; Rashkov, Iliya

    2010-08-11

    New antimicrobial microfibrous electrospun mats from styrene/maleic anhydride copolymers were prepared. Two approaches were applied: (i) grafting of poly(propylene glycol) monoamine (Jeffamine® M-600) on the mats followed by formation of complex with iodine; (ii) modification of the mats with amines of 8-hydroxyquinoline or biguanide type with antimicrobial activity. Microbiological screening against S. aureus, E. coli and C. albicans revealed that both the formation of complex with iodine and the covalent attachment of 5-amino-8-hydroxyquinoline or of chlorhexidine impart high antimicrobial activity to the mats. In addition, S. aureus bacteria did not adhere to modified mats.

  12. Adsorption of alkenyl succinic anhydride from solutions in carbon tetrachloride on a fine magnetite surface

    NASA Astrophysics Data System (ADS)

    Balmasova, O. V.; Ramazanova, A. G.; Korolev, V. V.

    2016-06-01

    The adsorption of alkenyl succinic anhydride from a solution in carbon tetrachloride on a fine magnetite surface at a temperature of 298.15 K is studied using fine magnetite, which forms the basis of magnetic fluids, as the adsorbent. An adsorption isotherm is recorded and interpreted in terms of the theory of the volume filling of micropores (TVFM). Adsorption process parameters are calculated on the basis of the isotherm. It is shown that at low equilibrium concentrations, the experimental adsorption isotherm is linear in the TVFM equation coordinates.

  13. The modification and characterization of maleic anhydride-styrene-methyl metacrylate terpolymer by poly(ethylene adipate)

    NASA Astrophysics Data System (ADS)

    Boztuğ, Ali; Basan, Satilmiş

    2007-03-01

    In this study, the functionality of maleic anhydride was utilized in the maleic anhydride-styrene-methyl metacrylate (MAStMMA) terpolymer. First, the polyester of poly(ethylene adipate), PEA, polycondensation copolymer was synthesized from ethylene glycol and adipic acid monomers. PEA was then modified on its maleic anhydride units in the MAStMMA terpolymer which has been synthesized previously. This modified copolymer was characterized by FTIR (Fourier Transform Infrared spectroscopy). The viscosimetric and thermomechanical characterization of MAStMMA terpolymer and its modified copolymer were also performed and the results were compared. The modified copolymer obtained was found to be more elastic and more soluble, and had lower viscosity and density.

  14. Preparation, characterization and antibacterial activity of octenyl succinic anhydride modified inulin.

    PubMed

    Zhang, Xiaoyun; Zhang, Ye-Wang; Zhang, Hongyin; Yang, Qiya; Wang, Haiying; Zhang, Guochao

    2015-01-01

    Octenyl succinic anhydride modified inulin (In-OSA) was synthesized via chemical modification of inulin with octenyl succinic anhydride (OSA). The esterification of inulin with OSA was confirmed by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and degree of substitution (DS) calculation. Antibacterial activity of In-OSA against Staphylococcus aureus and Escherichia coli was investigated by minimum inhibitory concentration (MIC) and inhibition rate determination. The results showed that inhibition rates against both E.coli and S. aureus increased with the increase of the In-OSA concentration. And the MICs against E. coli and S. aureus were 1% and 0.5% (w/v), respectively. The antibacterial mechanism was analyzed with the results of the proteins and nucleic acids leakage, SEM and negative staining transmission electron microscopy (TEM). Both the leakages of proteins and nucleic acids increased with the increase of the In-OSA concentration. The leakage occurred mainly in the early stage which indicated that cell membrane and wall were destroyed by In-OSA quickly. The images of SEM and negative staining TEM suggested that the cell membranes and cell walls of S. aureus were damaged more severely and even destroyed completely; but only pores appeared on the surface of E. coli.

  15. Catalytic behavior of Sn/Bi metal powder in anhydride-based epoxy curing.

    PubMed

    Jang, Keon-Soo; Eom, Yong-Sung; Moon, Jong-Tae; Oh, Yong-Soo; Nam, Jae-Do

    2009-12-01

    In this paper, we report the catalytic activity of the Sn/Bi alloy beads and its acceleration of the exothermic epoxy curing reactions in various thermal conditions and bead compositions. As being used as low-melting solder balls in electronic interconnection processes with various epoxy systems, it was found that the Sn/Bi beads substantially lowered the exothermic peak temperature of the diglycidyl ether of bisphenol A (DGEBA)/anhydride systems in up to ca. 140 degrees C depending on different types of anhydride curing agents. The catalytic activation of Sn/Bi powder was initiated with a small amount of Sn/Bi powder, for example, lowering ca. 50 degrees C of the exothermic peak temperature by adding only 0.1 vol% of Sn/Bi powder. The catalytic capability of the powder was increased by using smaller sized beads corresponding to larger catalytic surface area at the same volume fraction. Exhibiting a latent catalytic effect, the catalytic activity of Sn/Bi powder was remained latent at temperatures lower than 100 degrees C in isothermal conditions.

  16. Flexible Polyimide Aerogel Cross-linked by Poly(maleic Anhydride-alt-alkylene)

    NASA Technical Reports Server (NTRS)

    Guo, Haiquan; Meador, Mary Ann B.; Wilkewitz, Brittany Marie

    2014-01-01

    Aerogels are potential materials for aerospace applications due to their lower thermal conductivity, lighter weight, and low dielectric constant. However, silica aerogels are restricted due to their inherent fragility, hygroscopic nature, and poor mechanical properties, especially in extreme aerospace environments. In order to fit the needs of aerospace applications, developing new thermal insulation materials that are flexible, and moisture resistant is needed. To this end, we fabricated a series of polyimide aerogels crosslinked with different poly(maleic anhydride-alt-alkylene)s as seen in Scheme 1. The polyimide oligomers were made with 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA), and different diamines or diamine combinations. The resulting aerogels have low density (0.06 gcm3 to 0.16 gcm3) and high surface area (240-440 m2g). The effect of the different backbone structures on density, shrinkage, porosity, surface area, mechanical properties, moisture resistance and thermal properties will be discussed. These novel polyalkylene-imide aerogels may be potential candidates for applications such as space suit insulation for planetary surface missions, insulation for inflatable structures for habitats, inflatable aerodynamic decelerators for entry, descent and landing (EDL) operations, and cryotank insulation for advance space propulsion systems. Scheme 1. Network of polyimide aerogels crosslinked with deifferent poly(maleic anhydride).

  17. Dual-Functional Hydrazide-Reactive and Anhydride-Containing Oligomeric Hydrogel Building Blocks.

    PubMed

    Kascholke, Christian; Loth, Tina; Kohn-Polster, Caroline; Möller, Stephanie; Bellstedt, Peter; Schulz-Siegmund, Michaela; Schnabelrauch, Matthias; Hacker, Michael C

    2017-03-13

    Biomimetic hydrogels are advanced biomaterials that have been developed following different synthetic routes. Covalent postfabrication functionalization is a promising strategy to achieve efficient matrix modification decoupled of general material properties. To this end, dual-functional macromers were synthesized by free radical polymerization of maleic anhydride with diacetone acrylamide (N-(1,1-dimethyl-3-oxobutyl)acrylamide) and pentaerythritol diacrylate monostearate. Amphiphilic oligomers (Mn < 7.5 kDa) with anhydride contents of 7-20% offered cross-linking reactivity to yield rigid hydrogels with gelatinous peptides (E = 4-13 kPa) and good cell adhesion properties. Mildly reactive methyl ketones as second functionality remained intact during hydrogel formation and potential of covalent matrix modification was shown using hydrazide and hydrazine model compounds. Successful secondary dihydrazide cross-linking was demonstrated by an increase of hydrogel stiffness (>40%). Efficient hydrazide/hydrazine immobilization depending on solution pH, hydrogel ketone content as well as ligand concentration for bioconjugation was shown and reversibility of hydrazone formation was indicated by physiologically relevant hydrazide release over 7 days. Proof-of-concept experiments with hydrazido-functionalized hyaluronan demonstrated potential for covalent aECM immobilization. The presented dual-functional macromers have perspective as reactive hydrogel building blocks for various biomedical applications.

  18. Pomelo peel modified with acetic anhydride and styrene as new sorbents for removal of oil pollution.

    PubMed

    Chai, Wenbo; Liu, Xiaoyan; Zou, Junchen; Zhang, Xinying; Li, Beibei; Yin, Tiantian

    2015-11-05

    Pomelo peel (PP), as one of the well-known agricultural wastes, is cost-effective and environmentally friendly. Based on PP, two new kinds of oil sorbents were prepared by using acetic anhydride and styrene. The structures of raw pomelo peel (RP), acetic anhydride-treated pomelo peel (AP) and styrene-treated pomelo peel (SP) were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), contact-angle (CA) measurements. The optimum reaction conditions for preparation of AP and SP were also investigated. The resulting products exhibited better oil sorption capacity than that of RP for diesel and lubricating oil, also SP had better oil sorption capacity than AP, while the oil sorption capacities of SP for diesel and lubricating oil reached 18.91 and 26.36 g/g, respectively. Adsorption kinetics was well described by the pseudo-second-order model. The results indicated that AP and SP, especially SP could be used as the substitute for non-biodegradable oil sorption materials.

  19. Effect of reagent access on the reactivity of coals. Final report. [Maleic anhydride; dialkylmaleates

    SciTech Connect

    Larsen, J.W.

    1983-04-01

    The objective of this work is to determine the extent to which the mass transport of reagents into solid coals limits the reactivity of those coals. The purpose of task one is to determine the effect of reagent access on the acid catalyzed depolymerization of coals using phenols and/or alkyl phenyl ethers. For task two, the purpose is to determine the effect of coal swelling on its rate of reaction with a dienophile. Work on depolymerization of coals in hot, acidic phenol has been completed. The conclusion is that due to incomplete depolymerization, the complications of competing Friedel-Crafts alkylation, and the condensation reactions of the solvent, the depolymerization of coals in hot, acidic phenol is not a useful technique for solubilizing coals for structural investigations. In task two, the rate of the Diels-Alder reaction between bituminous coals and maleic anhydride was found to be diffusion controlled. The observations of simple Fickian diffusion and reaction rate constants much slower than the Diels-Alder reaction of maleic anhydride and anthracene have no other reasonable explanation than rate limiting mass transport. The diffusion rates were found to be independent of the degree of solvent swelling of the coal. In addition, the dependence of the observed rates on temperature and the size of the dienophile were measured. Results obtained using a series of dialkylmaleates are presented. Size was found to play only a small role as long as the reagent is planar. 2 tables.

  20. Efficient photochemical generation of peroxycarboxylic nitric anhydrides with ultraviolet light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Rider, N. D.; Taha, Y. M.; Odame-Ankrah, C. A.; Huo, J. A.; Tokarek, T. W.; Cairns, E.; Moussa, S. G.; Liggio, J.; Osthoff, H. D.

    2015-07-01

    Photochemical sources of peroxycarboxylic nitric anhydrides (PANs) are utilized in many atmospheric measurement techniques for calibration or to deliver an internal standard. Conventionally, such sources rely on phosphor-coated low-pressure mercury (Hg) lamps to generate the UV light necessary to photo-dissociate a dialkyl ketone (usually acetone) in the presence of a calibrated amount of nitric oxide (NO) and oxygen (O2). In this manuscript, a photochemical PAN source in which the Hg lamp has been replaced by arrays of ultraviolet light-emitting diodes (UV-LEDs) is described. The output of the UV-LED source was analyzed by gas chromatography (PAN-GC) and thermal dissociation cavity ring-down spectroscopy (TD-CRDS). Using acetone, diethyl ketone (DIEK), diisopropyl ketone (DIPK), or di-n-propyl ketone (DNPK), respectively, the source produces peroxyacetic (PAN), peroxypropionic (PPN), peroxyisobutanoic (PiBN), or peroxy-n-butanoic nitric anhydride (PnBN) from NO in high yield (> 90 %). Box model simulations with a subset of the Master Chemical Mechanism (MCM) were carried out to rationalize product yields and to identify side products. The present work demonstrates that UV-LED arrays are a viable alternative to current Hg lamp setups.

  1. A self-crosslinking thermosetting monomer with both epoxy and anhydride groups derived from Tung oil fatty acids: Synthesis and properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A self-crosslinking compound with epoxy groups and anhydride groups (GEMA) has been successfully synthesized from Tung oil fatty acid by reacting with maleic anhydride via the Diels-Alder reaction. GEMA has very good storage stability and can be cured with trace amounts of tertiary amine. This advan...

  2. A self-crosslinking thermosetting monomer with both epoxy and anhydride groups derived from tung oil fatty acids: Synthesis and properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A self-crosslinking compound with epoxy groups and anhydride groups (GEMA) has been successfully synthesized from tung oil fatty acid by reacting with maleic anhydride via the Diels-Alder reaction. GEMA has very good storage stability and could be cured with trace amounts of tertiary amine. This ad...

  3. Soluble Synthetic Analogs of Malaria Pigment: Structure of Mesohematin Anhydride [FeIII(MP-IX)]2 and Solution Interaction with Chloroquine

    SciTech Connect

    D Bohle; E Dodd; A Kosar; L Sharma; P Stephens; L Suarez; D Tazoo

    2011-12-31

    Changing the vinyl groups of hematin anhydride to either ethyl or hydrogen groups results in increased solubility (Por=porphyrin). Determination of the weak binding constants of the antimalarial drug chloroquine to dimers of these hematin anhydride analogues suggests that solution-phase heme/drug interactions alone are unlikely to be the origin of the action of the drug.

  4. SELECTIVE HYDROGENATION OF MALEIC ANHYDRIDE TO Y-BUTYROLACTONE OVER PD/AL(2)O(3) CATALYST USING SUPERCRITICAL CO(2) AS SOLVENT

    EPA Science Inventory

    A selective hydrogenation of maleic anhydride to either y-butyrolactone or succinic anhydride over simple Pd/Al(2)O(3) catalyst under supercritical CO(2) medium is described for the first time which has considerable promise for obht lab-scale as well as industrial selective hydro...

  5. Preparation and characterization of poly(methyl methacrylate) and poly(maleic anhydride-co-diallyl phthalate) grafted carbon black through γ-ray irradiation

    NASA Astrophysics Data System (ADS)

    Bo, Yang; Cui, Jiayang; Cai, Yangben; Xu, Shiai

    2016-02-01

    In this study, the grafting polymerization of methyl methacrylate (MMA) monomer and maleic anhydride/diallyl phthalate (MAH/DAP) co-monomer onto the surface of carbon black (CB) were carried out at room temperature and normal pressure by γ-ray irradiation. The surface chemistry of grafted CBs were characterized by infrared spectroscopy (IR), thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results show that there are some remanent polymers on the surface of modified CBs after extract for 48 h, indicating that poly(methyl methacrylate) (PMMA) and poly(MAH-co-DAP) have been successfully grafted onto the surface of CB without using initiator due to the high energy of γ-ray irradiation. Dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that the grafted CBs have smaller average aggregate size and better dispersibility than that of CB in absolute ethanol. In addition, it was found that the amount of oxygen groups and the irradiation doses/dose rates have little effect on the grafting degree of CB.

  6. A novel reactive processing technique: using telechelic polymers to reactively compatibilize polymer blends

    SciTech Connect

    Ashcraft, Earl C; Ji, Haining; Mays, Jimmy; Dadmun, Mark D

    2009-01-01

    Difunctional reactive polymers, telechelics, were used to reactively form multiblock copolymers in situ when melt-blended with a blend of polystyrene and polyisoprene. To quantify the ability of the copolymer to compatibilize the blends, the time evolution of the domain size upon annealing was analyzed by SEM. It was found that the most effective parameter to quantify the ability of the copolymer to inhibit droplet coalescence is Kreltstable, the relative coarsening constant multiplied by the stabilization time. These results indicate that intermediate-molecular-weight telechelic pairs of both highly reactive Anhydride-PS-Anhydride/NH2-PI-NH2 and slower reacting Epoxy-PS-Epoxy/COOH-PI-COOH both effectively suppress coalescence, with the optimal molecular weight being slightly above the critical molecular weight of the homopolymer,Mc. The effects of telechelic loading were also investigated, where the optimal loading concentration for this system was 0.5 wt %, as higher concentrations exhibited a plasticizing effect due to the presence of unreacted low-molecular-weight telechelics present in the blend. A determination of the interfacial coverage of the copolymer shows that a conversion of 1.5-3.0% was required for 20% surface coverage at 5.0 wt % telechelic loading, indicating a large excess of telechelics in this system. At the optimal loading level of 0.5 wt %, a conversion of 15% was required for 20% surface coverage. The results of these experiments provide a clear understanding of the role of telechelic loading and molecular weight on its ability to reactively form interfacial modifiers in phase-separated polymer blends and provide guidelines for the development of similar reactive processing schemes that can use telechelic polymers to reactively compatibilize a broad range of polymer blends.

  7. Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

    Harrison, J. S.; Ounaies, Z.; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    The purpose of this review is to detail the current theoretical understanding of the origin of piezoelectric and ferroelectric phenomena in polymers; to present the state-of-the-art in piezoelectric polymers and emerging material systems that exhibit promising properties; and to discuss key characterization methods, fundamental modeling approaches, and applications of piezoelectric polymers. Piezoelectric polymers have been known to exist for more than forty years, but in recent years they have gained notoriety as a valuable class of smart materials.

  8. Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

    PubMed Central

    Jeon, Jong Yeob; Eo, Seong Chan; Varghese, Jobi Kodiyan

    2014-01-01

    Summary The (salen)Co(III) complex 1 tethering four quaternary ammonium salts, which is a highly active catalyst in CO2/epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA) copolymerizations and PO/CO2/PA terpolymerizations. In the PO/PA copolymerizations, full conversion of PA was achieved within 5 h, and strictly alternating copolymers of poly(1,2-propylene phthalate)s were afforded without any formation of ether linkages. In the PO/CO2/PA terpolymerizations, full conversion of PA was also achieved within 4 h. The resulting polymers were gradient poly(1,2-propylene carbonate-co-phthalate)s because of the drift in the PA concentration during the terpolymerization. Both polymerizations showed immortal polymerization character; therefore, the molecular weights were determined by the activity (g/mol-1) and the number of chain-growing sites per 1 [anions in 1 (5) + water (present as impurity) + ethanol (deliberately fed)], and the molecular weight distributions were narrow (M w/M n, 1.05–1.5). Because of the extremely high activity of 1, high-molecular-weight polymers were generated (M n up to 170,000 and 350,000 for the PO/PA copolymerization and PO/CO2/PA terpolymerization, respectively). The terpolymers bearing a substantial number of PA units (f PA, 0.23) showed a higher glass-transition temperature (48 °C) than the CO2/PO alternating copolymer (40 °C). PMID:25161738

  9. Organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium or azolium enolates.

    PubMed

    Morrill, Louis C; Smith, Andrew D

    2014-09-07

    This tutorial review highlights the organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium/azolium enolates. The generation and synthetic utility of these powerful intermediates is highlighted through their application in various methodologies including aldol-lactonisations, Michael-lactonisations/lactamisations and [2,3]-rearrangements.

  10. Tetrahydrophthalic Anhydrides as Addition Curing Polyimide End Caps: Thermal Isomerization of Methylendianiline 3,6-Diphenyltetrahydrophthalic Bisimides

    NASA Technical Reports Server (NTRS)

    Frimer, Aryeh A.; Gilinsky-Sharon, Pessia; Gottlieb, Hugo E.; Meador, Mary Ann B.; Johnston, J. Christopher

    2005-01-01

    In depth NMR studies confirm that heating a 1:2 mixture of cis, cis, cis 3,6-diphenyltetrahydrophthalic anhydride (end cap 9c) with methylenedianiline at 316 C initially yields the corresponding highly congested cis, cis, cis 3,6-diphenyltetrahydrophthalic bisimide 11, which is converted at this temperature to the observed product, the less hindered trans, cis, trans isomer 12.

  11. RAFT copolymerization of itaconic anhydride and 2-methoxyethyl acrylate: a multifunctional scaffold for preparation of "clickable" gold nanoparticles.

    PubMed

    Javakhishvili, Irakli; Kasama, Takeshi; Jankova, Katja; Hvilsted, Søren

    2013-05-25

    RAFT copolymerization of 2-methoxyethyl acrylate and itaconic anhydride - a monomer derived from renewable resources - is carried out in a controlled fashion. The copolymer allows preparation of gold nanoparticles with abundant surficial carboxyl and alkyne functional groups that are dendronized via Cu(I)-mediated "click" reaction.

  12. Evolutionary Importance of the Intramolecular Pathways of Hydrolysis of Phosphate Ester Mixed Anhydrides with Amino Acids and Peptides

    PubMed Central

    Liu, Ziwei; Beaufils, Damien; Rossi, Jean-Christophe; Pascal, Robert

    2014-01-01

    Aminoacyl adenylates (aa-AMPs) constitute essential intermediates of protein biosynthesis. Their polymerization in aqueous solution has often been claimed as a potential route to abiotic peptides in spite of a highly efficient CO2-promoted pathway of hydrolysis. Here we investigate the efficiency and relevance of this frequently overlooked pathway from model amino acid phosphate mixed anhydrides including aa-AMPs. Its predominance was demonstrated at CO2 concentrations matching that of physiological fluids or that of the present-day ocean, making a direct polymerization pathway unlikely. By contrast, the occurrence of the CO2-promoted pathway was observed to increase the efficiency of peptide bond formation owing to the high reactivity of the N-carboxyanhydride (NCA) intermediate. Even considering CO2 concentrations in early Earth liquid environments equivalent to present levels, mixed anhydrides would have polymerized predominantly through NCAs. The issue of a potential involvement of NCAs as biochemical metabolites could even be raised. The formation of peptide–phosphate mixed anhydrides from 5(4H)-oxazolones (transiently formed through prebiotically relevant peptide activation pathways) was also observed as well as the occurrence of the reverse cyclization process in the reactions of these mixed anhydrides. These processes constitute the core of a reaction network that could potentially have evolved towards the emergence of translation. PMID:25501391

  13. Evolutionary Importance of the Intramolecular Pathways of Hydrolysis of Phosphate Ester Mixed Anhydrides with Amino Acids and Peptides

    NASA Astrophysics Data System (ADS)

    Liu, Ziwei; Beaufils, Damien; Rossi, Jean-Christophe; Pascal, Robert

    2014-12-01

    Aminoacyl adenylates (aa-AMPs) constitute essential intermediates of protein biosynthesis. Their polymerization in aqueous solution has often been claimed as a potential route to abiotic peptides in spite of a highly efficient CO2-promoted pathway of hydrolysis. Here we investigate the efficiency and relevance of this frequently overlooked pathway from model amino acid phosphate mixed anhydrides including aa-AMPs. Its predominance was demonstrated at CO2 concentrations matching that of physiological fluids or that of the present-day ocean, making a direct polymerization pathway unlikely. By contrast, the occurrence of the CO2-promoted pathway was observed to increase the efficiency of peptide bond formation owing to the high reactivity of the N-carboxyanhydride (NCA) intermediate. Even considering CO2 concentrations in early Earth liquid environments equivalent to present levels, mixed anhydrides would have polymerized predominantly through NCAs. The issue of a potential involvement of NCAs as biochemical metabolites could even be raised. The formation of peptide-phosphate mixed anhydrides from 5(4H)-oxazolones (transiently formed through prebiotically relevant peptide activation pathways) was also observed as well as the occurrence of the reverse cyclization process in the reactions of these mixed anhydrides. These processes constitute the core of a reaction network that could potentially have evolved towards the emergence of translation.

  14. Evolutionary importance of the intramolecular pathways of hydrolysis of phosphate ester mixed anhydrides with amino acids and peptides.

    PubMed

    Liu, Ziwei; Beaufils, Damien; Rossi, Jean-Christophe; Pascal, Robert

    2014-12-11

    Aminoacyl adenylates (aa-AMPs) constitute essential intermediates of protein biosynthesis. Their polymerization in aqueous solution has often been claimed as a potential route to abiotic peptides in spite of a highly efficient CO2-promoted pathway of hydrolysis. Here we investigate the efficiency and relevance of this frequently overlooked pathway from model amino acid phosphate mixed anhydrides including aa-AMPs. Its predominance was demonstrated at CO2 concentrations matching that of physiological fluids or that of the present-day ocean, making a direct polymerization pathway unlikely. By contrast, the occurrence of the CO2-promoted pathway was observed to increase the efficiency of peptide bond formation owing to the high reactivity of the N-carboxyanhydride (NCA) intermediate. Even considering CO2 concentrations in early Earth liquid environments equivalent to present levels, mixed anhydrides would have polymerized predominantly through NCAs. The issue of a potential involvement of NCAs as biochemical metabolites could even be raised. The formation of peptide-phosphate mixed anhydrides from 5(4H)-oxazolones (transiently formed through prebiotically relevant peptide activation pathways) was also observed as well as the occurrence of the reverse cyclization process in the reactions of these mixed anhydrides. These processes constitute the core of a reaction network that could potentially have evolved towards the emergence of translation.

  15. Kinetics of Hydrolysis of Acetic Anhydride by In-Situ FTIR Spectroscopy: An Experiment for the Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Haji, Shaker; Erkey, Can

    2005-01-01

    A reaction kinetics experiment for the chemical engineering undergraduate laboratory course was developed in which in-situ Fourier Transfer Infrared spectroscopy was used to measure reactant and product concentrations. The kinetics of the hydrolysis of acetic anhydride was determined by experiments carried out in a batch reactor. The results…

  16. Aggregate structure and effect of phthalic anhydride modified soy protein on the mechanical properties of styrene-butadiene copolymer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aggregate structure of phthalic anhydride (PA) modified soy protein isolate (SPI) was investigated by estimating its fractal dimension from the equilibrated dynamic strain sweep experiments. The estimated fractal dimensions of the filler aggregates were less than 2, indicating that these partic...

  17. Releasable Conjugation of Polymers to Proteins.

    PubMed

    Gong, Yuhui; Leroux, Jean-Christophe; Gauthier, Marc A

    2015-07-15

    Many synthetic strategies are available for preparing well-defined conjugates of peptides/proteins and polymers. Most reports on this topic involve coupling methoxy poly(ethylene glycol) to therapeutic proteins, a process referred to as PEGylation, to increase their circulation lifetime and reduce their immunogenicity. Unfortunately, the major dissuading dogma of PEGylation is that, in many cases, polymer modification leads to significant (or total) loss of activity/function. One approach that is gaining momentum to address this challenge is to release the native protein from the polymer with time in the body (releasable PEGylation). This contribution will present the state-of-the-art of this rapidly evolving field, with emphasis on the chemistry behind the release of the peptide/protein and the means for altering the rate of release in biological fluids. Linkers discussed include those based on the following: substituted maleic anhydride and succinates, disulfides, 1,6-benzyl-elimination, host-guest interactions, bicin, β-elimination, biodegradable polymers, E1cb elimination, β-alanine, photoimmolation, coordination chemistry, zymogen activation, proteolysis, and thioesters.

  18. Silver-containing polymer composition used in spacecraft and semiconductor optoelectronics control systems

    NASA Astrophysics Data System (ADS)

    Ivanov, A. A.; Tuev, V. I.

    2015-10-01

    The copolymer of the vinyl chloride-maleic anhydride and silver nano- and microparticle (70 wt %) composition is offered as a conductive adhesive for fixing various chips on the dielectric substrate. The wiring volume resistivity is up to 3.1×10-8 Ohm×m. The adhesive strength of the silver-containing polymer composition (70% of Ag) applied under a shear on the dielectric substrate is 106 N/mm2. Adhesive layers obtained from these substances have a high thermal conductivity up to λ = 199.93 W/m×K that depends on the amount of Ag in the polymer composition.

  19. Silver-containing polymer composition used in spacecraft and semiconductor optoelectronics control systems

    SciTech Connect

    Ivanov, A. A. Tuev, V. I.

    2015-10-27

    The copolymer of the vinyl chloride-maleic anhydride and silver nano- and microparticle (70 wt %) composition is offered as a conductive adhesive for fixing various chips on the dielectric substrate. The wiring volume resistivity is up to 3.1×10{sup −8} Ohm×m. The adhesive strength of the silver-containing polymer composition (70% of Ag) applied under a shear on the dielectric substrate is 106 N/mm{sup 2}. Adhesive layers obtained from these substances have a high thermal conductivity up to λ = 199.93 W/m×K that depends on the amount of Ag in the polymer composition.

  20. Effects of Amine and Anhydride Curing Agents on the VARTM Matrix Processing Properties

    NASA Technical Reports Server (NTRS)

    Grimsley, Brian W.; Hubert, Pascal; Song, Xiaolan; Cano, Roberto J.; Loos, Alfred C.; Pipes, R. Byron

    2002-01-01

    To ensure successful application of composite structure for aerospace vehicles, it is necessary to develop material systems that meet a variety of requirements. The industry has recently developed a number of low-viscosity epoxy resins to meet the processing requirements associated with vacuum assisted resin transfer molding (VARTM) of aerospace components. The curing kinetics and viscosity of two of these resins, an amine-cured epoxy system, Applied Poleramic, Inc. VR-56-4 1, and an anhydride-cured epoxy system, A.T.A.R.D. Laboratories SI-ZG-5A, have been characterized for application in the VARTM process. Simulations were carried out using the process model, COMPRO, to examine heat transfer, curing kinetics and viscosity for different panel thicknesses and cure cycles. Results of these simulations indicate that the two resins have significantly different curing behaviors and flow characteristics.

  1. Stereodynamic control of star-epoxy/anhydride crosslinking actuated by liquid-crystalline phase transitions.

    PubMed

    Pin, Jean-Mathieu; Mija, Alice; Sbirrazzuoli, Nicolas

    2017-03-08

    The epoxy/anhydride copolymerization kinetics of an original star-epoxy monomer (TriaEP) was explored in dynamic heating mode using a series of isoconversional methods. Negative values of the apparent activation energy (Eα) related to an anti-Arrhenius behavior were observed. The transition from Arrhenius to anti-Arrhenius behavior and vice versa depending on the Eα of polymerization was correlated with the dynamics of mesophasic fall-in/fall-out events, physically induced transition (PIT) and chemically induced transition (CIT). This self-assembly phenomenon induces the generation of an anisotropic crosslinked architecture exhibiting both nematic discotic (ND) and nematic columnar (NC) organization. Particular emphasis was placed on evaluating the juxtaposition/contribution of the liquid-crystalline transitions to crosslinking, considering both the reaction dynamics and the macromolecular vision.

  2. "Push-pull" 1,8-naphthalic anhydride with multiple triphenylamine groups as electron donor

    NASA Astrophysics Data System (ADS)

    Wang, Limin; Shi, Yan; Zhao, Yingyuan; Liu, Heyuan; Li, Xiyou; Bai, Ming

    2014-01-01

    In this paper, the "push-pull" molecules consisting of different number of triphenylamino groups and 1,8-naphthalic anhydride ring were designed and synthesized. The UV-vis absorption and emission spectra of these compounds were recorded. Along with the increase on the number of the electron donating triphenylamino groups, both the absorption and emission bands show significant red shift. More importantly, the fluorescence quantum yields drop sharply along with the increase on the number of triphenylamino groups. The molecular structure, the frontier molecular orbital energies and the energy gaps between the highest occupied molecular orbital (HOMO) and the lowest un-occupied molecular orbital (LUMO) were calculated with DFT method. The calculated results indicate that the connection of more electron donating triphenylamino groups in molecule caused a change for the first excited state from an intramolecular charge transfer (ICT) state to an intramolecular electron transfer state (ET). This change on the first excited state has led to the fluorescence quenching.

  3. Mechanism of highly improved electrical properties in polypropylene by chemical modification of grafting maleic anhydride

    NASA Astrophysics Data System (ADS)

    Zhou, Yao; Hu, Jun; Dang, Bin; He, Jinliang

    2016-10-01

    This paper reports excellent electrical properties in polypropylene grafted with maleic anhydride (PP-g-MAH) and a related mechanism of the enhanced electrical properties. The chemical structure of PP-g-MAH was analyzed and its effect on space charge accumulation, electrical breakdown strength and DC conductivity was studied. Compared with pure PP, the PP-g-MAH exhibits remarkably suppressed space charge accumulation, enhanced electrical breakdown strength and reduced conduction current. The mechanism enhancing the electrical properties was studied by measuring the trap level distribution. It can be explained that abundant deep traps are introduced in PP-g-MAH with the introduction of polar groups in MAH, which reduces the charge mobility and raises the charge injection barrier so as to suppress space charge accumulation. This investigation would contribute to propose a new material modification strategy for designing high-voltage direct current insulation material in addition to the inclusion of nanoparticles.

  4. Improved removal of malachite green from aqueous solution using chemically modified cellulose by anhydride.

    PubMed

    Zhou, Yanmei; Min, Yinghao; Qiao, Han; Huang, Qi; Wang, Enze; Ma, Tongsen

    2015-03-01

    Cellulose modified with maleic (M) and phthalic (P) anhydride, to be named CMA and CPA, were tested as feasible adsorbents for the removal of malachite green from aqueous solution. At the same time, the uptake ability of natural cellulose was also studied for comparison. The structure of material was characterized by FT-IR and XRD. The effects of solution pH, initial dye concentration, contact time and temperature were investigated in detail by batch adsorption experiments. The kinetic and isotherm studies suggested that the adsorption followed the pseudo-second-order model and Langmuir isotherm. The maximum adsorption capacity on CMA and CPA were 370 mg g(-1) and 111 mg g(-1), respectively. Furthermore, the thermodynamics studies indicated the spontaneous nature of adsorption of malachite green on adsorbents. All the studied results showed that the modified cellulose could be used as effective adsorption material for the removal of malachite green from aqueous solutions.

  5. Ionic liquids as novel solvents for biosynthesis of octenyl succinic anhydride-modified waxy maize starch.

    PubMed

    Li, Dandan; Zhang, Xiwen; Tian, Yaoqi

    2016-05-01

    Biosynthesis of octenyl succinic anhydride (OSA) starch was investigated using ionic liquids (ILs) as reaction media. Waxy maize starch was pretreated in 1-butyl-3-methylimidazolium chlorine and then esterified with OSA in 1-octyl-3-methylimidazolium nitrate by using Novozyme 435 as catalyst. The degree of substitution of OSA starch reached 0.0130 with 5 wt% starch concentration and 1 wt% lipase dosage based on ILs weight at 50 °C for 3h. The formation of OSA starch was confirmed by fourier transform infrared spectroscopy. Scanning electron microscopy and X-ray diffraction revealed that the morphology and crystal structure of starch were significantly destroyed. Thermogravimetric analysis showed that esterification decreased the thermal stability of starch. The successful lipase-catalyzed synthesis of OSA starch in ILs suggests that ILs are potential replacement of traditional organic solvents for starch ester biosynthesis.

  6. Synthesis and paste properties of octenyl succinic anhydride modified early Indica rice starch.

    PubMed

    Song, Xiao-yan; Chen, Qi-he; Ruan, Hui; He, Guo-qing; Xu, Qiong

    2006-10-01

    Octenyl succinic anhydride (OSA) modified early Indica rice starch was prepared in aqueous slurry systems using response surface methodology. The paste properties of the OSA starch were also investigated. Results indicated that the suitable parameters for the preparation of OSA starch from early Indica rice starch were as follows: reaction period 4 h, reaction temperature 33.4 degrees C, pH of reaction system 8.4, concentration of starch slurry 36.8% (in proportion to water, w/w), amount of OSA 3% (in proportion to starch, w/w). The degree of substitution was 0.0188 and the reaction efficiency was 81.0%. The results of paste properties showed that with increased OSA modification, the starch derivatives had higher paste clarity, decreased retrogradation and better freeze-thaw stability.

  7. Effects of hydrothermal pretreatment on subsequent octenylsuccinic anhydride (OSA) modification of cornstarch.

    PubMed

    Chen, Xu; He, Xiaowei; Huang, Qiang

    2014-01-30

    Cornstarch granules were hydrothermally pretreated and then esterified with octenylsuccinic anhydride (OSA). The physicochemical properties of cornstarch and hydrothermally pretreated OS-starch (H-OS-starch) were investigated. Results showed that hydrothermal pretreatments significantly increased the degree of substitution (DS) and reaction efficiency (RE) of H-OS-starch compared with the control. The higher the pretreatment temperature was, the more the OSA could go deep into the internal starch granules. The optimal pretreatment temperature for the OSA modification was 60°C. In addition, the OS groups appeared to be distributed throughout the OS-starch granules, especially on the surface, as shown by confocal laser scanning microscopy (CLSM). H-OS-starch had a slightly higher peak viscosity (Pv) and break down (BD) values, but lower pasting temperature (Tp) compared with the control OS-starch.

  8. Enhanced Activity of Nanocrystalline Beta Zeolite for Acylation of Veratrole with Acetic Anhydride.

    PubMed

    Aisha Mahmood Abdulkareem, Al-Turkustani; Selvin, Rosilda

    2016-04-01

    Friedel-Craft acylation of veratrole using homogeneous acid catalysts such as AlCl3, FeCl3, ZnCl2, and HF etc. produces acetoveratrone, (3',4'-dimethoxyacetophenone), which is the intermediate for synthesis of papavarine alkaloids. The problems associated with these homogeneous catalysts can be overcome by using heterogeneous solid catalysts. Since acetoveratrone is a larger molecule, large pore Beta zeolites with smaller particle sizes are beneficial for the liquid-phase acylation of veratrole, for easy diffusion of reactants and products. The present study aims in the acylation of veratrole with acetic anhydride using nanocrystalline Beta Zeolite catalyst. A systematic investigation of the effects of various reaction parameters was done. The catalysts were characterized for their structural features by using XRD, TEM and DLS analyses. The catalytic activity of nanocrystalline Beta zeolite was compared with commercial Beta zeolite for the acylation and was found that nanocrystalline Beta zeolite possessed superior activity.

  9. Structure and physicochemical properties of octenyl succinic anhydride modified starches: a review.

    PubMed

    Sweedman, Michael C; Tizzotti, Morgan J; Schäfer, Christian; Gilbert, Robert G

    2013-01-30

    Starches modified with octenyl succinic anhydride (OSA) have been used in a range of industrial applications, particularly as a food additive, for more than half a century. Interest in these products has grown in recent years as a result of new methods and applications becoming available. Due to a combination of OSA's hydrophobic and steric contribution and starch's peculiar highly branched macromolecular structure, these starch derivatives display useful stabilizing, encapsulating, interfacial, thermal, nutritional and rheological properties. We review the synthesis procedures, structural characterization methods and physico-chemical properties, and the influences of the botanical origins and structural parameters of OSA starches on physico-chemical properties. A better understanding of these features has the potential to lead to products with targeted macromolecular structures and optimized properties for specific applications.

  10. Crystal structures of alkylperoxo and anhydride intermediates in an intradiol ring-cleaving dioxygenase

    SciTech Connect

    Knoot, Cory J.; Purpero, Vincent M.; Lipscomb, John D.

    2014-12-29

    Intradiol aromatic ring-cleaving dioxygenases use an active site, nonheme Fe3+ to activate O2 and catecholic substrates for reaction. The inability of Fe3+ to directly bind O2 presents a mechanistic conundrum. The reaction mechanism of protocatechuate 3,4-dioxygenase is investigated in this paper using the alternative substrate 4-fluorocatechol. This substrate is found to slow the reaction at several steps throughout the mechanistic cycle, allowing the intermediates to be detected in solution studies. When the reaction was initiated in an enzyme crystal, it was found to halt at one of two intermediates depending on the pH of the surrounding solution. The X-ray crystal structure of the intermediate at pH 6.5 revealed the key alkylperoxo-Fe3+ species, and the anhydride-Fe3+ intermediate was found for a crystal reacted at pH 8.5. Intermediates of these types have not been structurally characterized for intradiol dioxygenases, and they validate four decades of spectroscopic, kinetic, and computational studies. In contrast to our similar in crystallo crystallographic studies of an Fe2+-containing extradiol dioxygenase, no evidence for a superoxo or peroxo intermediate preceding the alkylperoxo was found. This observation and the lack of spectroscopic evidence for an Fe2+ intermediate that could bind O2 are consistent with concerted formation of the alkylperoxo followed by Criegee rearrangement to yield the anhydride and ultimately ring-opened product. Finally, structural comparison of the alkylperoxo intermediates from the intra- and extradiol dioxygenases provides a rationale for site specificity of ring cleavage.

  11. Crystal structures of alkylperoxo and anhydride intermediates in an intradiol ring-cleaving dioxygenase

    DOE PAGES

    Knoot, Cory J.; Purpero, Vincent M.; Lipscomb, John D.

    2014-12-29

    Intradiol aromatic ring-cleaving dioxygenases use an active site, nonheme Fe3+ to activate O2 and catecholic substrates for reaction. The inability of Fe3+ to directly bind O2 presents a mechanistic conundrum. The reaction mechanism of protocatechuate 3,4-dioxygenase is investigated in this paper using the alternative substrate 4-fluorocatechol. This substrate is found to slow the reaction at several steps throughout the mechanistic cycle, allowing the intermediates to be detected in solution studies. When the reaction was initiated in an enzyme crystal, it was found to halt at one of two intermediates depending on the pH of the surrounding solution. The X-ray crystalmore » structure of the intermediate at pH 6.5 revealed the key alkylperoxo-Fe3+ species, and the anhydride-Fe3+ intermediate was found for a crystal reacted at pH 8.5. Intermediates of these types have not been structurally characterized for intradiol dioxygenases, and they validate four decades of spectroscopic, kinetic, and computational studies. In contrast to our similar in crystallo crystallographic studies of an Fe2+-containing extradiol dioxygenase, no evidence for a superoxo or peroxo intermediate preceding the alkylperoxo was found. This observation and the lack of spectroscopic evidence for an Fe2+ intermediate that could bind O2 are consistent with concerted formation of the alkylperoxo followed by Criegee rearrangement to yield the anhydride and ultimately ring-opened product. Finally, structural comparison of the alkylperoxo intermediates from the intra- and extradiol dioxygenases provides a rationale for site specificity of ring cleavage.« less

  12. Crystal structures of alkylperoxo and anhydride intermediates in an intradiol ring-cleaving dioxygenase

    PubMed Central

    Knoot, Cory J.; Purpero, Vincent M.; Lipscomb, John D.

    2015-01-01

    Intradiol aromatic ring-cleaving dioxygenases use an active site, nonheme Fe3+ to activate O2 and catecholic substrates for reaction. The inability of Fe3+ to directly bind O2 presents a mechanistic conundrum. The reaction mechanism of protocatechuate 3,4-dioxygenase is investigated here using the alternative substrate 4-fluorocatechol. This substrate is found to slow the reaction at several steps throughout the mechanistic cycle, allowing the intermediates to be detected in solution studies. When the reaction was initiated in an enzyme crystal, it was found to halt at one of two intermediates depending on the pH of the surrounding solution. The X-ray crystal structure of the intermediate at pH 6.5 revealed the key alkylperoxo-Fe3+ species, and the anhydride-Fe3+ intermediate was found for a crystal reacted at pH 8.5. Intermediates of these types have not been structurally characterized for intradiol dioxygenases, and they validate four decades of spectroscopic, kinetic, and computational studies. In contrast to our similar in crystallo crystallographic studies of an Fe2+-containing extradiol dioxygenase, no evidence for a superoxo or peroxo intermediate preceding the alkylperoxo was found. This observation and the lack of spectroscopic evidence for an Fe2+ intermediate that could bind O2 are consistent with concerted formation of the alkylperoxo followed by Criegee rearrangement to yield the anhydride and ultimately ring-opened product. Structural comparison of the alkylperoxo intermediates from the intra- and extradiol dioxygenases provides a rationale for site specificity of ring cleavage. PMID:25548185

  13. Crystal structures of alkylperoxo and anhydride intermediates in an intradiol ring-cleaving dioxygenase.

    PubMed

    Knoot, Cory J; Purpero, Vincent M; Lipscomb, John D

    2015-01-13

    Intradiol aromatic ring-cleaving dioxygenases use an active site, nonheme Fe(3+) to activate O2 and catecholic substrates for reaction. The inability of Fe(3+) to directly bind O2 presents a mechanistic conundrum. The reaction mechanism of protocatechuate 3,4-dioxygenase is investigated here using the alternative substrate 4-fluorocatechol. This substrate is found to slow the reaction at several steps throughout the mechanistic cycle, allowing the intermediates to be detected in solution studies. When the reaction was initiated in an enzyme crystal, it was found to halt at one of two intermediates depending on the pH of the surrounding solution. The X-ray crystal structure of the intermediate at pH 6.5 revealed the key alkylperoxo-Fe(3+) species, and the anhydride-Fe(3+) intermediate was found for a crystal reacted at pH 8.5. Intermediates of these types have not been structurally characterized for intradiol dioxygenases, and they validate four decades of spectroscopic, kinetic, and computational studies. In contrast to our similar in crystallo crystallographic studies of an Fe(2+)-containing extradiol dioxygenase, no evidence for a superoxo or peroxo intermediate preceding the alkylperoxo was found. This observation and the lack of spectroscopic evidence for an Fe(2+) intermediate that could bind O2 are consistent with concerted formation of the alkylperoxo followed by Criegee rearrangement to yield the anhydride and ultimately ring-opened product. Structural comparison of the alkylperoxo intermediates from the intra- and extradiol dioxygenases provides a rationale for site specificity of ring cleavage.

  14. Studies of phthalocyanine-containing polymers

    NASA Astrophysics Data System (ADS)

    Lee, Pui Sze Priscilla

    This thesis reports the synthesis, spectroscopic and photophysical properties, and in vitro photodynamic activities of several series of phthalocyanine-containing polymers including poly(norbornene), poly(anhydride), and poly(epsilon-caprolactone). Chapter 1 gives a general overview of phthalocyanines including their synthesis and applications. Special emphasis has been placed on hydrophilic and non-aggregated phthalocyanines and their use in photodynamic therapy. In addition, different classes of phthalocyanine-containing polymers will also be mentioned. Chapter 2 discusses the synthesis, characterization, and photophysical properties of a series of poly(norbornene)s with zinc(II) phthalocyanine and amino acid moieties. The copolymers were prepared by copolymerization of 2-(2-norbornenylmethoxy)phthalocyaninatozinc(II) with 5-norbornenes substituted with phenylalanine and tyrosine. As shown by absorption and fluorescence spectroscopy, phthalocyanines in this series of polymer exhibit a rather strong aggregation tendency. Chapter 3 presents the synthesis, characterization, photophysical properties, and in vitro photodynamic activities of a related series of amino acid- and sugar-containing poly(norbornene)s connected axially to a silicon(IV) phthalocyanine core. These polymers exhibit a good solubility in common organic solvents. Due to the axial polymeric substituents, these compounds are free from aggregation and give a high singlet oxygen quantum yield. These polymers in Cremophor EL emulsions also show a high photodynamic activity against HepG2 cells, in particular the polymer with protected galactose moieties. Chapter 4 reports a series of silicon(IV) phthalocyanines substituted with two poly(sebacic anhydride) chains as the axial ligands. The polymers form nanoparticles in water in the presence of surfactants cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulphate (SDS). The degradation of the nanoparticles was carried out in alkaline media and was

  15. Enzyme immobilization on reactive polymer films.

    PubMed

    Cordeiro, Ana L; Pompe, Tilo; Salchert, Katrin; Werner, Carsten

    2011-01-01

    Immobilized enzymes are currently used in many bioanalytical and biomedical applications. This protocol describes the use of thin films of maleic anhydride copolymers to covalently attach enzymes directly to solid supports at defined concentrations. The concentration and activity of the surface-bound enzymes can be tuned over a wide range by adjusting the concentration of enzyme used for immobilization and the physicochemical properties of the polymer platform, as demonstrated here for the proteolytic enzyme Subtilisin A. The versatile method presented allows for the immobilization of biomolecules containing primary amino groups to a broad variety of solid carriers, ranging from silicon oxide surfaces to standard polystyrene well plates and metallic surfaces. The approach can be used to investigate the effects of immobilized enzymes on cell adhesion, and on the catalysis of specific reactions.

  16. Novel thermoresponsive assemblies of co-grafted natural and synthetic polymers for water purification.

    PubMed

    Paneysar, Joginder Singh; Barton, Stephen; Chandra, Sudeshna; Ambre, Premlata; Coutinho, Evans

    2017-03-01

    Water contamination and its purification are a global problem. The current approach to purify water is reduction of impurities to acceptable levels. One of the ways to achieve this is by use of water-soluble polymers that extract organic and metallic contaminants, from water. This paper presents a blend of composite polymers that eliminates both the contaminants simultaneously by the principle of adsorption at lower critical solution temperature. These composite polymers have been synthesized by grafting poly(N,N-diethylacrylamide), poly(N-isopropylacrylamide) and poly(N-vinylcaprolactam) on-to the natural polymer chitosan or its derivatives, giving smart graft polymeric assemblies (GPAs). One of the graft polymers, GPA-2, exhibits excellent adsorption properties able to remove metal ions like cadmium, cobalt, copper, lead, iron and also organic impurities like chlorophenol and phthalic anhydride. Studies reveal that 6 mg/ml GPA-2 is able to effect a 100% removal of organic impurities - chlorophenol (50 ppm) and phthalic anhydride (70 ppm) - from water, while complete removal of the heavy metal ions (Cu(+2), Co(+2) and Cd(+2)) together at 30 ppm concentration has been achieved with 7.5 mg/ml GPA-2. The reduction in level of impurities along with recyclability and reproducibility in the elimination spectrum makes these assemblies promising materials in water treatment.

  17. Development of Highly Active and Regioselective Catalysts for the Copolymerization of Epoxides with Cyclic Anhydrides: An Unanticipated Effect of Electronic Variation.

    PubMed

    DiCiccio, Angela M; Longo, Julie M; Rodríguez-Calero, Gabriel G; Coates, Geoffrey W

    2016-06-08

    Recent developments in polyester synthesis have established several systems based on zinc, chromium, cobalt, and aluminum catalysts for the ring-opening alternating copolymerization of epoxides with cyclic anhydrides. However, to date, regioselective processes for this copolymerization have remained relatively unexplored. Herein we report the development of a highly active, regioselective system for the copolymerization of a variety of terminal epoxides and cyclic anhydrides. Unexpectedly, electron withdrawing substituents on the salen framework resulted in a more redox stable Co(III) species and longer catalyst lifetime. Using enantiopure propylene oxide, we synthesized semicrystalline polyesters via the copolymerization of a range of epoxide/anhydride monomer pairs.

  18. Water-soluble metal working fluids additives derived from the esters of acid anhydrides with higher alcohols for aluminum alloy materials.

    PubMed

    Yamamoto, Syutaro; Tomoda, Hideyuki; Watanabe, Shoji

    2007-01-01

    Water-soluble metal working fluids are used for processing of aluminum alloy materials. This short article describes properties of new additives in water-soluble metal working fluids for aluminum alloy materials. Many half esters or diesters were prepared from the reactions of higher alcohols with acid anhydrides. Interestingly, diesters of PTMG (tetrahydrofuran oligomer, MW = 650 and 1000) and polybutylene oxide (MW = 650) with maleic anhydride and succinic anhydride showed both of an excellent anti-corrosion property for aluminum alloy and a good hard water tolerance. The industrial soluble type processing oils including these additives also showed anti-corrosion property and hard water tolerance.

  19. New polymer systems: Chain extension by dianhydrides

    NASA Technical Reports Server (NTRS)

    Rhein, R. A.; Ingham, J. D.

    1974-01-01

    Three anhydrides provide effective chain extension of hydroxy-terminated polyalkylene oxides and polybutadienes. Novel feature of these anhydride reactants is that they are difunctional as anhydrides, but they are tetrafunctional if conditions are selected that lead to total esterification or reaction of all carboxyl groups.

  20. Star Polymers.

    PubMed

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  1. Polymer Chemistry

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  2. Synthesis of BISGMA derivatives, properties of their polymers and composites.

    PubMed

    Sandner, B; Baudach, S; Davy, K W; Braden, M; Clarke, R L

    1997-01-01

    2,2-Bis[4-(2 hydroxy-3-methacryloyloxy propoxy) phenyl] propane (BisGMA) is commonly the main component of the organic matrix of dental filling materials. Derivatives of BisGMA were synthesized from the diglycidyl ether of Bisphenol A (DGEBA) by the parallel reaction with methacrylic acid (MAA) and isophthalic acid as well as mixtures of methacrylic anhydride with palmitic acid and acetic anhydride, respectively, whereby MAA was partially substituted by the latter components. By this technique the structure of BisGMA monomer could be varied with regard to weight content of C=C double bonds, the hydrophilicity of the molecule as well as its flexibility or stiffness. Free-radical initiated homopolymerization of the monomers was carried out at 80 degrees C. Composites, prepared from mixtures of monomers with triethylene glycol dimethacrylate (TEGDMA) filled with 76% silica were room temperature polymerized using both redox and photoinitiated techniques. The polymerization shrinkage, diffusion coefficients of water in the crosslinked polymer, and some thermal properties of the homopolymers were determined. Mechanical properties of the resulting polymers and composites are compared to those of BisGMA itself.

  3. A biotin-conjugated pyridine-based isatoic anhydride, a selective room temperature RNA-acylating agent for the nucleic acid separation.

    PubMed

    Ursuegui, S; Yougnia, R; Moutin, S; Burr, A; Fossey, C; Cailly, T; Laayoun, A; Laurent, A; Fabis, F

    2015-03-28

    Isatoic anhydride derivatives, including a biotin and a disulfide linker were specifically designed for nucleic acid separation. 2'-OH selective RNA acylation, capture of biotinylated RNA adducts by streptavidin-coated magnetic beads and disulfide chemical cleavage led to isolation of highly enriched RNA samples from an initial 9/1 DNA-RNA mixture. Starting from the parent compound N-methylisatoic anhydride A which was used at 65 °C, we improved the extraction process by designing a new generation of isatoic anhydrides that are able to react under smoother conditions. Among them, a pyridine-based isatoic anhydride derivative 15f was found to be reactive at room temperature, leading to enhance the efficiency and selectivity of the extraction process by significantly reducing DNA side extraction. The extracted and purified RNAs can then be detected by RT-PCR.

  4. Modular access to vicinally functionalized allylic (thio)morpholinonates and piperidinonates by substrate-controlled annulation of 1,3-azadienes with hexacyclic anhydrides.

    PubMed

    Braunstein, Hannah; Langevin, Spencer; Khim, Monique; Adamson, Jonathan; Hovenkotter, Katie; Kotlarz, Lindsey; Mansker, Brandon; Beng, Timothy K

    2016-09-21

    A modular substrate-controlled hexannulation of inherently promiscuous 1,3-azadienes with hexacyclic anhydrides, which affords versatile vicinally functionalized allylic lactams, in high yields, regio- and stereoselectivities is described.

  5. Effects of shear flow on reactive coupling of polymer chains at melt interfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Jianbin; Lodge, Timothy; Macosko, Christopher

    2006-03-01

    The coupling reaction of functional polymers at static polymer-polymer interfaces is typically much slower than that at interfaces formed during mixing (see, for example, Reference 1). We have demonstrated that the imposed simple shear can accelerate coupling reactions at flat interfaces. For amine-terminal polystyrene (PS-NH2)/anhydride terminal poly(methyl methacrylate) (PMMA-anh), the PMMA-anh conversion under dynamic oscillation even at strain amplitude as small as 1% is seven times that under static conditions. Reaction time and temperature and the total interfacial area were maintained the same. Similar behavior was found for both bilayer and multilayer samples. Under steady simple shear, the reaction conversion and the rate of interfacial area generation are comparable to that of batch mixing. *Macosko, C. W.; Jeon. H. K.; Hoye, T. R. Prog. Polym. Sci. 2005, 30, 939.

  6. Polymers & People

    ERIC Educational Resources Information Center

    Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

    2004-01-01

    Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

  7. Kinetics of the reactions of the acid anhydrides with aromatic amines in aprotic solvents. M.S. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Sugg, E.; Mason, J. G.

    1983-01-01

    Work has revealed that diamine derivatives of diphenylmethane (IV), diphenyl ether (V), benzophenone (IV), fluorene (VII), and fluorenone (VIII) polymerizations with pyromellitic dianhydride in DMA were dependent on the basicity of the amine compound. The correlation between the basicity of the amine and its reactivity with phthalic anhydride was determined. Basicity measurements were made by potentiometric titration of each amine in an acetonitrile-water solvent system, from which the pKa of the amine could be determined. Reactivity was defined in terms of the second order rate constant derived form spectrophotometric examination of the reaction between each amine and phthalic anhydride in DMA. This reaction was expected to proceed in either one (for a monoamine) or two (for a diamine) stages.

  8. Characterization of the Structure-Processing-Performance Relations of Phenylethynyl Phthalic Anhydride Crosslinked Fluorinated Polyimides (AFR-PEPA-N) and Their Carbon Fiber Composites

    DTIC Science & Technology

    2007-04-12

    FA9550-04-1-0137 Relations of Phenylethynyl Phthalic Anhydride Crosslinked Fluorinated Polyimides (AFR-PEPA-N) and Their Carbon Fiber Composites 5b. GRANT...structure-processing-performance relations of phenylethynyl phthatic anhydride crosslinked fluorinated polyimides (AFR-PEPA-N) and their carbon fiber...composites for applications for future Air Force vehicles and associated propulsion systems . The technical areas that were primarily pursued and

  9. Methylol polyesters of C12-C22 hydrocarbon substituted succinic anhydride or acid, their preparation and use as additives for lubricants and fuels

    SciTech Connect

    Gutierrez, A.; Ryer, J.; Shaub, H.; Winans, E.D.

    1980-06-24

    Methylol polyester derivatives of C12-C22 hydrocarbon substituted succinic anhydride or acid which are the equimolar reaction products of said C12-C22 hydrocarbon substituted succinic anhydride or acid and a cyclic poly(Methylol) compound provide activity: in fuels as rust inhibitors; in automatic transmission fluids as copper corrosion inhibitors; and, in automotive, industrial and lubricating oils as sludge dispersants , rust-inhibitors, friction reducers (Lubricity agents) and copper alloy corrosion inhibitors.

  10. Application of palladium-catalyzed carboxyl anhydride-boronic acid cross coupling in the synthesis of novel bile acids analogs with modified side chains.

    PubMed

    Mayorquín-Torres, Martha C; Flores-Álamo, Marcos; Iglesias-Arteaga, Martin A

    2015-09-01

    Palladium-catalyzed cross coupling of 4-methoxycarbonyl phenyboronic acid with acetylated bile acids in which the carboxyl functions was activated by formation of a mixed anhydride with pivalic anhydride afforded the cross coupled compounds, which were converted in novel side chain modified bile acids by one pot carbonyl reduction/removal of the protecting acetyl groups by Wolff-Kishner reduction. Unambiguous assignments of the NMR signals and crystal characterization of the heretofore unknown compounds are provided.

  11. Polymers with complexing properties. Simple poly(amino acids)

    NASA Technical Reports Server (NTRS)

    Roque, J. M.

    1978-01-01

    The free amino (0.3 equiv/residue) and carboxyl (0.5 equiv/residue) groups of thermal polylysine increased dramatically on treatment with distilled water. The total hydrolysis of such a polymer was abnormal in that only about 50% of the expected amino acids were recovered. Poly (lysine-co-alanine-co-glycine) under usual conditions hydrolyzed completely in 8 hours; whereas, when it was pretreated with diazomethane, a normal period of 24 hours was required to give (nearly) the same amounts of each free amino acid as compared with those obtained from the untreated polymer. The amino groups of the basic thermal poly(amino acids) were sterically hindered. The existence of nitrogen atoms linking two or three chains and reactive groups (anhydride, imine) were proposed.

  12. Ficusmicrochlorin A-C, two new methoxy lactone chlorins and an anhydride chlorin from the leaves of Ficus microcarpa.

    PubMed

    Lin, Huan-You; Chiu, Hsi-Lin; Lu, Te-Ling; Tzeng, Chih-Ying; Lee, Tzong-Huei; Lee, Ching-Kuo; Shao, Yi-Yuan; Chen, Chiy-Rong; Chang, Chi-I; Kuo, Yueh-Hsiung

    2011-01-01

    Two new methoxy lactone chlorins ficusmicrochlorin A (1) and ficusmicrochlorin B (2), and one new anhydride chlorin ficusmicrochlorin C (3), along with eight known pheophytins were isolated from the leaves of Ficus microcarpa. Their structures were determined by the extensive 1D- and 2D-NMR techniques. New pheophytin compound was rarely obtained from natural sources. In the past ten years, only three new natural pheophytins were characterized.

  13. Mixed Anhydride Intermediates in the Reaction of 5(4H)‐Oxazolones with Phosphate Esters and Nucleotides

    PubMed Central

    Liu, Ziwei; Rigger, Lukas; Rossi, Jean‐Christophe; Sutherland, John D.

    2016-01-01

    Abstract 5(4H)‐Oxazolones can be formed through the activation of acylated α‐amino acids or of peptide C termini. They constitute potentially activated intermediates in the abiotic chemistry of peptides that preceded the origin of life or early stages of biology and are capable of yielding mixed carboxylic‐phosphoric anhydrides upon reaction with phosphate esters and nucleotides. Here, we present the results of a study aimed at investigating the chemistry that can be built through this interaction. As a matter of fact, the formation of mixed anhydrides with mononucleotides and nucleic acid models is shown to take place at positions involving a mono‐substituted phosphate group at the 3’‐ or 5’‐terminus but not at the internal phosphodiester linkages. In addition to the formation of mixed anhydrides, the subsequent intramolecular acyl or phosphoryl transfers taking place at the 3’‐terminus are considered to be particularly relevant to the common prebiotic chemistry of α‐amino acids and nucleotides. PMID:27534830

  14. Sensitive detection of proteins in polyacrylamide gel via isatoic anhydride derivatization: Introduction of a low-cost fluorescent prelabeling procedure.

    PubMed

    Asadollahi, Kazem; Rafiee, Saharnaz; Riazi, Gholamhossein

    2016-10-01

    Here, we introduce isatoic anhydride as a sensitive and commodious fluorescent prelabel for detection of proteins in one-dimensional polyacrylamide gels. High reactivity of isatoic anhydride with nucleophiles in mild alkaline environments makes it an appropriate tag for labeling of biomolecules. In this study, we show that preelectrophoresis labeling of proteins with isatoic anhydride for few minutes at room temperature allows detection of 2-4 ng of standard proteins, BSA and lysozyme, per band. Proteins were successfully labeled in the presence of a wide range of common biological reagents and in crude cell extract. The labeled proteins have the same electrophoretic migration in comparison to unlabeled proteins; however the application of saturation labeling method results in slight band broadening. Compatibility of the method with downstream processes was assessed by tryptic digestion of labeled proteins and study of peptide mixture using gel electrophoresis which revealed partial digestion of labeled proteins due to lysine modification. The present procedure is sensitive, rapid, and inexpensive and is a promising alternative for current protein staining procedures, where downstream processes are not desired.

  15. Mixed Anhydride Intermediates in the Reaction of 5(4H)-Oxazolones with Phosphate Esters and Nucleotides.

    PubMed

    Liu, Ziwei; Rigger, Lukas; Rossi, Jean-Christophe; Sutherland, John D; Pascal, Robert

    2016-10-10

    5(4H)-Oxazolones can be formed through the activation of acylated α-amino acids or of peptide C termini. They constitute potentially activated intermediates in the abiotic chemistry of peptides that preceded the origin of life or early stages of biology and are capable of yielding mixed carboxylic-phosphoric anhydrides upon reaction with phosphate esters and nucleotides. Here, we present the results of a study aimed at investigating the chemistry that can be built through this interaction. As a matter of fact, the formation of mixed anhydrides with mononucleotides and nucleic acid models is shown to take place at positions involving a mono-substituted phosphate group at the 3'- or 5'-terminus but not at the internal phosphodiester linkages. In addition to the formation of mixed anhydrides, the subsequent intramolecular acyl or phosphoryl transfers taking place at the 3'-terminus are considered to be particularly relevant to the common prebiotic chemistry of α-amino acids and nucleotides.

  16. Separation of maleic anhydride grafted polypropylene using multidimensional high-temperature liquid chromatography.

    PubMed

    Prabhu, K N; Macko, T; Brüll, R; Remerie, K; Tacx, J; Garg, P; Ginzburg, A

    2016-04-08

    Functionalization addresses a property gap of polyolefins and opens new perspectives due to improved surface properties in applications like composites (e.g., glass fiber reinforced polypropylene) and anti-corrosive coatings for metals. Various techniques have been developed to characterize functionalized polyolefins, yet no analytical approach addressing their chemical heterogeneity exists. Using High Temperature Size Exclusion Chromatography (HT-SEC) coupled to infrared spectroscopy we could show for two model samples of polypropylene grafted maleic anhydride (PP-g-MA), differing in their nominal MA content, that the grafting density increases with decreasing molar mass. Crystallization Analysis Fractionation (CRYSTAF) does not enable to separate these samples according to their composition to the extent required. Yet, when using High Temperature High Performance Liquid Chromatography (HT-HPLC), with either silica gel or Mica as stationary phase and a gradient mobile phase, a deformulation into a grafted and a non-grafted fraction could be achieved. This was confirmed by analyzing the eluted fractions by infrared spectroscopy. Hyphenating the separation according to composition with a separation according to molar mass (HT-HPLC x HT-SEC) enabled for the first time to reveal the bivariate distribution of PP-g-MA with regard to the molar mass and composition. Using on-line infrared detection quantitative information on the compositional and molar mass parameters of the individual fractions could be obtained.

  17. Four-year evaluation of workers exposed to trimellitic anhydride. A brief report

    SciTech Connect

    McGrath, K.G.; Roach, D.; Zeiss, C.R.; Patterson, R.

    1984-09-01

    In a four-year clinical, immunologic, and environmental study of trimellitic anhydride (TMA) exposure in a single plant, 20 workers exposed to TMA powder were evaluated in 1979 and a total of 32 workers were evaluated from 1979 to 1983. Two distinct groups emerged before and after workplace control improvements were made in 1979. Seventeen of the original 20 workers were available for longitudinal study through 1983. Annual clinical evaluations and serum radioimmunoassays for total antibody binding and specific IgE binding to 125I TM-HSA (human serum albumin) were performed on all 32 workers. In 1979, six workers had antibody against TM-HSA, three had the late respiratory systemic syndrome, and two had TMA-induced allergic rhinitis or allergic rhinitis and asthma. One worker had antibody against TM-HSA without illness. Fifteen additional workers were evaluated longitudinally after institution of several workplace control measures. Four of these 15 workers had TMA exposure prior to environmental improvement and joined the study in 1982. The remaining 11 workers joined the study in 1982 and had at least two years of TMA exposure in the modified workplace. None of these 11 workers developed a TMA-induced immunologic syndrome or significant total or specific IgE antibody binding to 125I TM-HSA.

  18. Effect of maleic anhydride on the damping property of magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Fan, Y. C.; Gong, X. L.; Jiang, W. Q.; Zhang, W.; Wei, B.; Li, W. H.

    2010-05-01

    In this study, maleic anhydride (MA) was selected as the compatibilizer to modify the interfaces of magnetorheological elastomers (MREs) for improving the damping property. Several samples of MREs with different contents of MA were prepared. The content of bound-rubber was measured by the extraction method. The microstructures were observed by using an environmental scanning electron microscope (SEM). The dynamic performances of these samples, including shear storage modulus, loss factor and MR effect were measured with a modified dynamic mechanical analyzer (DMA). The tensile strength was tested by using an electronic tensile machine. The experimental results indicate that both the content of bound-rubber and the compatibility between the magnetic particles and rubber matrix were enhanced with the increase of MA. The enhancement of the bond between the two phases resulted in different mechanical properties: the increase of shear storage modulus; the reduction of the loss factor; the stability improvement of the loss factor; the enhancement of the tensile strength; and the reduction of the MR effect.

  19. Cantharidin and its anhydride-modified derivatives: relation of structure to insecticidal activity.

    PubMed

    Sun, Wenbo; Liu, Zhongyi; Zhang, Yalin

    2012-12-20

    Cantharidin is a natural compound of novel structure with ideal insecticidal activity. However, the relationship of structure to insecticidal activity of cantharidin and its derivatives has not been ever clarified. To explore what determines the insecticidal activity structurally of cantharidin-related compounds, two series target compounds 6 and 7 were synthesized by replacing the anhydride ring of norcantharidin with an aromatic amine or fatty amine with different electron density, respectively. The structures of these compounds were characterized by 1H NMR, 13C NMR and HRMS-ESI. A bioassay showed that compounds 6 (a-m) lacked any larvicidal activity against Plutella xylostella; whereas their ring-opened partners 7 (a-m) provided a variety of larvicidal activities against P. xylostella, and compound 7f indicated the highest larvicidal activity with LC(50) value of 0.43 mM. The present work demonstrated that the form of the compound (cyclic or ring-opened) or their ability to hydrolyze facilely was the key to determine whether it exhibits larvicidal activity. Moreover, it revealed that the improvement of insecticidal activity required a reasonable combination of both aliphatic amide and aromatic amide moieties, and the type of substituent Y on the aniline ring was critical.

  20. Structural properties of pepsin-solubilized collagen acylated by lauroyl chloride along with succinic anhydride.

    PubMed

    Li, Conghu; Tian, Zhenhua; Liu, Wentao; Li, Guoying

    2015-10-01

    The structural properties of pepsin-solubilized calf skin collagen acylated by lauroyl chloride along with succinic anhydride were investigated in this paper. Compared with native collagen, acylated collagen retained the unique triple helix conformation, as determined by amino acid analysis, circular dichroism and X-ray diffraction. Meanwhile, the thermostability of acylated collagen using thermogravimetric measurements was enhanced as the residual weight increased by 5%. With the temperature increased from 25 to 115 °C, the secondary structure of native and acylated collagens using Fourier transform infrared spectroscopy measurements was destroyed since the intensity of the major amide bands decreased and the positions of the major amide bands shifted to lower wavenumber, respectively. Meanwhile, two-dimensional correlation spectroscopy revealed that the most sensitive bands for acylated and native collagens were amide I and II bands, respectively. Additionally, the corresponding order of the groups between native and acylated collagens was different and the correlation degree for acylated collagen was weaker than that of native collagen, suggesting that temperature played a small influence on the conformation of acylated collagen, which might be concluded that the hydrophobic interaction improved the thermostability of collagen.

  1. Dodecenylsuccinic anhydride derivatives of gum karaya (Sterculia urens): preparation, characterization, and their antibacterial properties.

    PubMed

    Padil, Vinod Vellora Thekkae; Senan, Chandra; Černík, Miroslav

    2015-04-15

    Esterifications of the tree-based gum, gum karaya (GK), using dodecenylsuccinic anhydride (DDSA) were carried out in aqueous solutions. GK was deacetylated using alkali treatment to obtain deacetylated gum karaya (DGK). The DGK and its DDSA derivative were characterized using gel permeation chromatography/multiangle laser light scattering (GPC/MALLS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), proton nuclear magnetic resonance spectroscopy ((1)H NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) analysis, and rheological studies. The degree of substitution was found to be 10.25% for DGK using (1)H NMR spectroscopy. The critical aggregation concentration of DDSA-DGK was determined using dye solubilization and surface tension methods. The antibacterial activity of the DDSA-DGK derivative was then investigated against Gram-negative Escherichia coli and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. The DDSA-DGK derivative has the potential for use as a stabilizing agent in food and nonfood applications. It can also be developed as an antibacterial agent.

  2. Effect of Persimmon Leaf Extract on Phthalic Anhydride-induced Allergic Response in Mice

    PubMed Central

    Mok, Ji Ye; Jeon, In Hwa; Cho, Jung-Keun; Park, Ji Min; Kim, Hyeon Soo; Kang, Hyun Ju; Kim, Hyung Soon; Jang, Seon Il

    2012-01-01

    The purpose of this study was to investigate the anti-allergy activities of persimmon leaf extract (PLE) on a phthalic anhydride (PA)-induced allergic mouse model. A human leukemic mast cell line (HMC-1) was used to examine the inhibitory activity of PLE on the histamine release by human leukemic mast cells. PLE inhibited histamine release from HMC-1 cells in response to cross-linkage of high-affinity IgE receptor-α (FcεRIα). Additionally, a PA-induced allergic mouse model was used to investigate the effects of PLE in vivo. Mice were orally administrated with or without PLE of single dose (250 mg/kg/day) for 31 days. Oral intake of PLE significantly inhibited passive cutaneous reactions. Oral administration of PLE to PA-induced allergic mice also led to a striking suppression of the development of contact dermatitis, ear swelling and lymph node weight. In addition, PA-specific IL-4 production of draining lymph node cells was markedly diminished by PLE oral administration, but not IFN-γ. Furthermore, PLE treatment suppressed PA-induced thymus and activation-regulated chemokine (CCL17) and cutaneous T cell-attracting chemokine (CCL27) expressions in ear tissues. Based on these results, we suggest that PLE may have therapeutic potential as an effective material for management of irritant contact dermatitis or related inflammatory diseases. PMID:24471058

  3. Immobilization of modified papain with anhydride groups on activated cotton fabric.

    PubMed

    Xue, Yong; Nie, Huali; Zhu, Limin; Li, Shubai; Zhang, Haitao

    2010-01-01

    Papain (EC 3.4.22.2) has been chemically modified using two novel reagents including different anhydrides of 1,2,4-benzenetricarboxylic and pyromellitic acids. Then, the modified papain was immobilized on the activated cotton fabric by a two-step method. The number of free amino groups in the modified protein was investigated through the 2,4,6-trinitrobenzenesulfonic acid method. Energy dispersive spectrometer was used to characterize papain immobilization. Some parameters of both modified and native papain immobilized on cotton fabric, such as optimum temperature, optimum pH, and the stabilities for reservation in various detergents were studied and compared. The resultant papain had its optimum pH shifted from 6.0 to 9.0. Compared with immobilized native papain, the thermal stability and the resistance to alkali and washing detergent of immobilized modified enzyme were improved considerably. When the concentration of detergent was 20 mg/ml, the activity of the immobilized pyromellitic papain retained about 40% of its original activity, whereas the native papain was almost inhibited. This work demonstrated that the cotton fabric immobilized modified papain has potential applications in the functional textiles field.

  4. Cantharidin and Its Anhydride-Modified Derivatives: Relation of Structure to Insecticidal Activity

    PubMed Central

    Sun, Wenbo; Liu, Zhongyi; Zhang, Yalin

    2013-01-01

    Cantharidin is a natural compound of novel structure with ideal insecticidal activity. However, the relationship of structure to insecticidal activity of cantharidin and its derivatives has not been ever clarified. To explore what determines the insecticidal activity structurally of cantharidin-related compounds, two series target compounds 6 and 7 were synthesized by replacing the anhydride ring of norcantharidin with an aromatic amine or fatty amine with different electron density, respectively. The structures of these compounds were characterized by 1H NMR, 13C NMR and HRMS-ESI. A bioassay showed that compounds 6 (a–m) lacked any larvicidal activity against Plutella xylostella; whereas their ring-opened partners 7 (a–m) provided a variety of larvicidal activities against P. xylostella, and compound 7f indicated the highest larvicidal activity with LC50 value of 0.43 mM. The present work demonstrated that the form of the compound (cyclic or ring-opened) or their ability to hydrolyze facilely was the key to determine whether it exhibits larvicidal activity. Moreover, it revealed that the improvement of insecticidal activity required a reasonable combination of both aliphatic amide and aromatic amide moieties, and the type of substituent Y on the aniline ring was critical. PMID:23344017

  5. Water absorption of poly(methyl methacrylate) containing 4-methacryloxyethyl trimellitic anhydride.

    PubMed

    Unemori, Masako; Matsuya, Yoko; Matsuya, Shigeki; Akashi, Akane; Akamine, Akifumi

    2003-04-01

    The amount of water absorption of poly(methyl methacrylate) (PMMA) containing 0, 1, 3 and 5 wt% of an adhesive monomer, 4-methacryloxyethyl trimellitic anhydride (4-META), was measured at 7 degrees C, 37 degrees C and 60 degrees C. After the water uptake reached equilibrium in specimens, they were desorbed to obtain a constant value and the absorption process was repeated. Mass changes in the second desorption were recorded for the storage temperatures of 37 degrees C and 60 degrees C. Multiple regression analyses were conducted on three independent variables, 4-META concentration, storage temperature and absorption-desorption cycle. A statistically significant relationship was found between the maximum water uptake and 4-META concentration, while there was no relationship between the maximum water uptake and diffusion coefficient obtained using the Fick's law. The negative relationship in the latter did not support the free space theory. The significant and positive relationship between the maximum water uptake and 4-META concentration demonstrates that water molecules diffuse through the formation of a hydrogen bond at polar sites. The maximum water uptake was not influenced by temperature, while the diffusion coefficient increased with the rise in temperature. The activation energy was 41-47 and 50-53 kJ/mol in the first and second absorption tests, respectively.

  6. Position of modifying groups on starch chains of octenylsuccinic anhydride-modified waxy maize starch.

    PubMed

    Bai, Yanjie; Kaufman, Rhett C; Wilson, Jeff D; Shi, Yong-Cheng

    2014-06-15

    Octenylsuccinic anhydride (OSA)-modified starches with a low (0.018) and high (0.092) degree of substitution (DS) were prepared from granular native waxy maize starch in aqueous slurry. The position of OS substituents along the starch chains was investigated by enzyme hydrolysis followed by chromatographic analysis. Native starch and two OS starches with a low and high DS had β-limit values of 55.9%, 52.8%, and 34.4%, respectively. The weight-average molecular weight of the β-limit dextrin from the OS starch with a low DS was close to that of the β-limit dextrin from native starch but lower than that of the β-limit dextrin from the OS starch with a high DS. Debranching of OS starches was incomplete compared with native starch. OS groups in the OS starch with a low DS were located on the repeat units near the branching points, whereas the OS substituents in the OS starch with a high DS occurred both near the branching points and the non-reducing ends.

  7. Granular size of potato starch affects structural properties, octenylsuccinic anhydride modification and flowability.

    PubMed

    Wang, Chan; Tang, Chuan-He; Fu, Xiong; Huang, Qiang; Zhang, Bin

    2016-12-01

    Native potato starch (PS) granules were separated into three size fractions: larger than 30μm (P-L), 15-30μm (P-M), and smaller than 15μm (P-S). The morphological and crystalline structure of fractionated potato starches were investigated by light and scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The P-L fraction showed ellipsoidal shape and B-type X-ray pattern, whereas the P-S fraction had spherical shape and A-type pattern. The fluorophore-assisted capillary electrophoresis data showed that the P-L fraction had more B2 chains and less short A and B1 chains than the P-S counterparts. Smaller granules with larger specific surface area had higher degree of substitution when reacted with octenylsuccinic anhydride (OSA), and showed more uniform distribution of octenylsuccinate substituents. Both OSA modified and unmodified P-S samples showed higher flowability compared with the P-L counterparts.

  8. Highly carbonylated cellulose nanofibrous membranes utilizing maleic anhydride grafting for efficient lysozyme adsorption.

    PubMed

    Ma, Juncheng; Wang, Xueqin; Fu, Qiuxia; Si, Yang; Yu, Jianyong; Ding, Bin

    2015-07-22

    Construction of adsorptive materials for simple, efficient, and high-throughput adsorption of proteins is critical to meet the great demands of highly purified proteins in biotechnological and biopharmaceutical industry; however, it has proven extremely challenging. Here, we report a cost-effective strategy to create carbonyl groups surface-functionalized nanofibrous membranes under mild conditions for positively charged protein adsorption. Our approach allows maleic anhydride to in situ graft on cellulose nanofibrous membranes (CMA) to construct adsorptive membranes with large surface area and tortuous porous structure. Thereby, the resultant CMA membranes exhibited high adsorption capacity of 160 mg g(-1), fast equilibrium within 12 h, and good reversibility to lysozyme. Moreover, the dynamic adsorption was performed under low pressure-drops (750 Pa), with a relatively high saturation adsorption amount of 118 mg g(-1), which matched well with the requirements for proteins purification. Considering the excellent adsorption performance of the as-prepared adsorptive membranes, this simple and intriguing approach may pave a way for the design and development of robust and cost-effective adsorption membranes to meet the great demands for fast and efficient adsorption of positively charged proteins.

  9. Reaction of octenylsuccinic anhydride with a mixture of granular starch and soluble maltodextrin.

    PubMed

    Bai, Yanjie; Shi, Yong-Cheng

    2013-11-06

    The reaction of octenylsuccinic anhydride (OSA) with a mixture of granular waxy maize starch and soluble maltodextrin was investigated. OSA was reacted with a 1:1 (w/w) mixture of the granular starch and maltodextrin at OSA levels of 1.5, 3, 9, and 15% (wt% based on starch weight). After the first 0.5h of the reaction, degree of substitution (DS) on maltodextrin reached 0.021, 0.030, 0.080, and 0.10 for 1.5, 3, 9, and 15% OSA, respectively, whereas DS for granular starch was only 0.0020, 0.0087, 0.014, and 0.016. At 2h of the reaction, the bound OS ratio of maltodextrin to granular starch was 10.8 when OSA concentration was 1.5% and the ratio decreased to ca. 5 at higher OSA concentrations. OSA preferred to react with maltodextrin than semi-crystalline granular starch when both existed in the system. OSA reacted with maltodextrin at a much faster rate and to a greater extent than with granular starch, but a significant amount of OSA reacted with granular starch at 3-15% OSA concentrations.

  10. Effect of the degree of substitution of octenyl succinic anhydride-banana starch on emulsion stability.

    PubMed

    Bello-Pérez, Luis A; Bello-Flores, Christopher A; Nuñez-Santiago, María del Carmen; Coronel-Aguilera, Claudia P; Alvarez-Ramirez, J

    2015-11-05

    Banana starch was esterified with octenylsuccinic anhydride (OSA) at different degree substitution (DS) and used to stabilize emulsions. Morphology, emulsion stability, emulsification index, rheological properties and particle size distribution of the emulsions were tested. Emulsions dyed with Solvent Red 26 showed affinity for the oil phase. Backscattering light showed three regions in the emulsion where the emulsified region was present. Starch concentration had higher effect in the emulsification index (EI) than the DS used in the study because similar values were found with OSA-banana and native starches. However, OSA-banana presented greater stability of the emulsified region. Rheological tests in emulsions with OSA-banana showed G'>G" values and low dependence of G' with the frequency, indicating a dominant elastic response to shear. When emulsions were prepared under high-pressure conditions, the emulsions with OSA-banana starch with different DS showed a bimodal distribution of particle size. The emulsion with OSA-banana starch and the low DS showed similar mean droplet diameter than its native counterpart. In contrast, the highest DS led to the highest mean droplet diameter. It is concluded that OSA-banana starch with DS can be used to stabilize specific emulsion types.

  11. Studies in iridoid synthesis. Chemoselective transformations of cis-1,2,4,6-tetrahydrophthalic anhydride.

    PubMed

    Stevens, Anne T; Bull, James R; Chibale, Kelly

    2008-02-07

    In the course of synthetic studies towards the development of diastereoselective routes to secoiridoid aglycones, cis-1,2,4,6-tetrahydrophthalic anhydride was transformed into the corresponding lactone cis-3a,4,7,7a-tetrahydro-3H-isobenzofuran-1-one, which served as a key precursor for a variety of chemoselective synthetic manipulations. Unsuccessful formylation of an ester intermediate resulted in a (E/Z) mixture of vinyl alcohols which were protected as acetates and as a single p-methoxybenzyl (PMB) ether (E) isomer. Dihydroxylation of the cyclohexene motif using OsO(4) led to the unexpected deprotection of the PMB ether. On the other hand, successful formylation of a suitably silyl protected lactonised intermediate was achieved using tert-butoxybis(dimethylamino)methane, or Bredereck's reagent. Tetrabutylammonium fluoride (TBAF) deprotection of a methoxyethoxymethyl (MEM)-ether intermediate serendipitously afforded an approximately 1 : 1 mixture of pyrano-pyranones, which are products of a seldom encountered intramolecular Michael addition, using an oxygen donor, to the terminus of an alpha,beta-unsaturated system, followed by beta-elimination of the MEM moiety.

  12. Nano-encapsulation of coenzyme Q10 using octenyl succinic anhydride modified starch.

    PubMed

    Cheuk, Sherwin Y; Shih, Frederick F; Champagne, Elaine T; Daigle, Kim W; Patindol, James A; Mattison, Christopher P; Boue, Stephen M

    2015-05-01

    Octenyl succinic anhydride modified starch (OSA-ST) was used to encapsulate coenzyme Q10 (CoQ10). CoQ10 was dissolved in rice bran oil and incorporated into an aqueous OSA-ST solution. High pressure homogenisation of the mixture was conducted at 170 MPa for 56 cycles. The resulting emulsion had a particle size range of 200-300 nm and the absolute zeta potential varied between 8.4 and 10.6 mV. CoQ10 retention of the emulsion and freeze dried products, determined by a hexane rinse, was 98.2%. Reconstitution of the freeze dried product in Mcllvaine citrate-phosphate buffers with pH values of 3-5 and temperatures at 4 and 25 °C had very little effect on the range and distribution of the nanoparticles' size. The inflection point of the zeta potential and pH plot occurred at the first pKa of succinic acid (pH 4.2), indicating succinate as the main influence over zeta potential.

  13. Polymer-coated fluorescent CdSe-based quantum dots for application in immunoassay.

    PubMed

    Speranskaya, Elena S; Beloglazova, Natalia V; Lenain, Pieterjan; De Saeger, Sarah; Wang, Zhanhui; Zhang, Suxia; Hens, Zeger; Knopp, Dietmar; Niessner, Reinhard; Potapkin, Dmitry V; Goryacheva, Irina Yu

    2014-03-15

    The paper describes all stages of synthesis and characterization of biocompatible CdSe-based core/shell quantum dots (QDs) and their application as fluorescent label for immunoassay. Special attention was focused on development of maleic anhydride-based amphiphilic polymers for QDs solubilization in aqueous media. In this work two PEG-amines were tried for polymer modification: monoamine Jeffamine M 1000 used previously in some researches and diamine Jeffamine ED-2003 applied for the first time for QDs solubilization. The use of different Jeffamines allows us to obtain QDs with carboxyl or amine functional groups available for conjugation. The influence of polymer composition on optical properties of the nanocrystals and their stability in aqueous solutions as well as on their conjugation with biomolecules was studied. QDs with different coatings were used as biolabels in quantitative fluorescence microtiter plate immunoassay and qualitative on-site column test. It was found that quantum dots covered with amphiphilic polymer prepared from poly(maleic anhydride-alt-1-octadecene) and Jeffamine ED-2003 retained up to 90% of their initial brightness, easily conjugated with protein and showed low non-specific adsorption. In optimized conditions the obtained QDs were successfully used for determination of mycotoxin deoxynivalenol in wheat and maize samples by fluorescence microtiter plate immunoassay with an IC50 of 220 μg kg(-1) and by on-site column test with cut-off of 500 μg kg(-1).

  14. PEG branched polymer for functionalization of nanomaterials with ultralong blood circulation.

    PubMed

    Prencipe, Giuseppe; Tabakman, Scott M; Welsher, Kevin; Liu, Zhuang; Goodwin, Andrew P; Zhang, Li; Henry, Joy; Dai, Hongjie

    2009-04-08

    Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched polymers for functionalization of various nanomaterials including carbon nanotubes, gold nanoparticles (NPs), and gold nanorods (NRs), affording high aqueous solubility and stability for these materials. We synthesize different surfactant polymers based upon poly(gamma-glutamic acid) (gammaPGA) and poly(maleic anhydride-alt-1-octadecene) (PMHC18). We use the abundant free carboxylic acid groups of gammaPGA for attaching lipophilic species such as pyrene or phospholipid, which bind to nanomaterials via robust physisorption. Additionally, the remaining carboxylic acids on gammaPGA or the amine-reactive anhydrides of PMHC18 are then PEGylated, providing extended hydrophilic groups, affording polymeric amphiphiles. We show that single-walled carbon nanotubes (SWNTs), Au NPs, and NRs functionalized by the polymers exhibit high stability in aqueous solutions at different pH values, at elevated temperatures, and in serum. Moreover, the polymer-coated SWNTs exhibit remarkably long blood circulation (t(1/2) = 22.1 h) upon intravenous injection into mice, far exceeding the previous record of 5.4 h. The ultralong blood circulation time suggests greatly delayed clearance of nanomaterials by the reticuloendothelial system (RES) of mice, a highly desired property for in vivo applications of nanomaterials, including imaging and drug delivery.

  15. Polymer-organoclay nanocomposites by melt processing

    NASA Astrophysics Data System (ADS)

    Cui, Lili

    2009-12-01

    Polymer-layered silicate nanocomposites based on a variety of polymer matrices and several organoclays were prepared by melt processing. A detailed characterization of the thermal degradation of several commercial and experimental organoclays often used to form polymer nanocomposites was reported. The surfactant type, loading, and purification level of organoclay significantly affect their thermal stability; however, broadly speaking, the results suggest that these differences in thermal stability do not appear to have much effect on the morphology and properties of the nanocomposites formed from them. It seems that the thermal stability of organoclays is not the key factor in organoclay exfoliation in melt processed polymer nanocomposites, since the exfoliation/dispersion process may have been completed on a time scale before the degradation of surfactant progresses to a detrimental level. Polymer nanocomposites have been made from a variety of polymers; however, few matrices have demonstrated the ability to readily exfoliate the organoclay as well as nylon 6, especially for highly hydrophobic materials like polyolefins. Hence, a significant part of this research work was devoted to explore various routes to improve polyolefin-organoclay interactions, and thus, organoclay exfoliation in these systems. Amine grafted polypropylenes and a conventionally used maleic anhydride grafted polypropylene were used as compatibilizers for polypropylene based nanocomposites to improve the organoclay exfoliation. A series of ethylene vinyl acetate copolymers, the polarity of which can be adjusted by varying their vinyl acetate contents, based nanocomposites were prepared as the model system to address the relationship between the polarity of the polymers and their preferences over various organoclay structures. Attempts were made to explore the effect of degree of neutralization of acid groups in ionomers on the morphology and properties of nanocomposites, and it seems that the

  16. Organometallic Polymers.

    ERIC Educational Resources Information Center

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  17. Polymer flooding

    SciTech Connect

    Littmann, W.

    1988-01-01

    This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past, polymer flooding was mainly the subject of research. The results of this research are spread over a vast number of single publications, making it difficult for someone who has not kept up-to-date with developments during the last 10-15 years to judge the suitability of polymer flooding to a particular field case. This book tries to fill that gap. An indispensable book for reservoir engineers, production engineers and lab. technicians within the petroleum industry.

  18. Polymers All Around You!

    ERIC Educational Resources Information Center

    Gertz, Susan

    Background information on natural polymers, synthetic polymers, and the properties of polymers is presented as an introduction to this curriculum guide. Details are provided on the use of polymer products in consumer goods, polymer recycling, polymer densities, the making of a polymer such as GLUEP, polyvinyl alcohol, dissolving plastics, polymers…

  19. Evaluation of poly(styrene-alt-maleic anhydride)-ethanol as enteric coating material.

    PubMed

    Lai, Xiaolin; Sun, Chengdong; Tian, Hua; Zhao, Wenjun; Gao, Lin

    2008-03-20

    This study aims at evaluating the potential of SMA-ethanol as enteric coating polymer for erythromycin tablets. SMA-ethanol was synthesized and characterized for physicochemical properties, molecular weight and thermal analysis. Free films were prepared by adding different kinds and amounts of plasticizers, the film surface topography was determined by a SEM, the tensile strength, water vapor transmission rate and moisture absorption were also tested to choose the most promising film. DBP was proved to be the most suitable plasticizer with a best using amount of 20%, such polymer films had low vapor transmission rate and low moisture absorption which were very important to an enteric coating material. The polymer was further characterized for film coating by evaluating the release of erythromycin tablets in vitro, tablets coated with SMA-ethanol can satisfy the drug release requests of USP when the film weight gains were between 4 and 6%; tablets coated with both a subcoat and the polymer showed excellent gastro-resistance, less than 0.2% drug release occurred even with weight gains as less as 2% after 2h exposure to acid (pH 1), while over 90% drug release occurred in pH 6.8 sodium phosphate buffer within 45 min, regardless of weight gains of coating material, moreover, we confirmed that the application of a subcoat could decrease the amount of required coating polymer. In conclusion, the potential use of SMA-ethanol as enteric coating material was demonstrated.

  20. Hydrothermal Synthesis and Processing of Barium Titanate Nanoparticles Embedded in Polymer Films.

    PubMed

    Toomey, Michael D; Gao, Kai; Mendis, Gamini P; Slamovich, Elliott B; Howarter, John A

    2015-12-30

    Barium titanate nanoparticles embedded in flexible polymer films were synthesized using hydrothermal processing methods. The resulting films were characterized with respect to material composition, size distribution of nanoparticles, and spatial location of particles within the polymer film. Synthesis conditions were varied based on the mechanical properties of the polymer films, ratio of polymer to barium titanate precursors, and length of aging time between initial formulations of the solution to final processing of nanoparticles. Block copolymers of poly(styrene-co-maleic anhydride) (SMAh) were used to spatially separate titanium precursors based on specific chemical interactions with the maleic anhydride moiety. However, the glassy nature of this copolymer restricted mobility of the titanium precursors during hydrothermal processing. The addition of rubbery butadiene moieties, through mixing of the SMAh with poly(styrene-butadiene-styrene) (SBS) copolymer, increased the nanoparticle dispersion as a result of greater diffusivity of the titanium precursor via higher mobility of the polymer matrix. Additionally, an aminosilane was used as a means to retard cross-linking in polymer-metalorganic solutions, as the titanium precursor molecules were shown to react and form networks prior to hydrothermal processing. By adding small amounts of competing aminosilane, excessive cross-linking was prevented without significantly impacting the quality and composition of the final barium titanate nanoparticles. X-ray diffraction and X-ray photoelectron spectroscopy were used to verify nanoparticle compositions. Particle sizes within the polymer films were measured to be 108 ± 5 nm, 100 ± 6 nm, and 60 ± 5 nm under different synthetic conditions using electron microscopy. Flexibility of the films was assessed through measurement of the glass transition temperature using dynamic mechanical analysis. Dielectric permittivity was measured using an impedance analyzer.

  1. Difructose anhydride III enhances bioavailability of water-insoluble iron in anemic Vietnamese women.

    PubMed

    Nakamori, Masayo; Hien, Vu Thi Thu; Khan, Nguyen Cong; Lam, Nguyen Thi; Dung, Nguyen Tri; Uotsu, Nobuo; Shiomi, Takuya; Okuhara, Yasuhide; Kise, Mitsuo; Shigematsu, Norihiro; Yamamoto, Shigeru

    2010-01-01

    Difructose anhydride III (DFAIII) is an indigestible disaccharide and has been shown to enhance iron absorption in animal studies; however, the effect has not been investigated in anemic subjects. We investigated the efficacy of co-administration of DFAIII with water-insoluble iron in the treatment of iron deficiency anemia in Vietnamese women. One hundred sixty-eight moderately anemic women (80 g/L

  2. Therapeutic effects of fermented soycrud on phenotypes of atopic dermatitis induced by phthalic anhydride

    PubMed Central

    Sung, Ji-Eun; Kwak, Moon-Hwa; Kim, Ji-Eun; Lee, Young-Ju; Kim, Ro-Ui; Kim, Eun-Ah; Lee, Ga-Young; Kim, Dong-Seob

    2013-01-01

    Atopic dermatitis (AD), which is known as the most common pruritic skin disease, is caused by epidermal barrier dysfunction, allergies, microwave radiation, histamine intolerance, and genetic defects. To investigate the therapeutic effects of fermented soycrud (FSC) on AD pathology, alteration of AD phenotypes induced by phthalic anhydride (PA) treatment was assessed by ear thickness analysis, measurement of immune-related organ weights, ELISA, and histological and pathological analyses of ICR mice after FSC treatment for 2 weeks. Except for water content, the concentrations of most major components were lower in FSC compared to common tofu (CMT). Thymus and lymph node weights were significantly reduced in ICR mice treated with PA+CMT or PA+FSC, whereas spleen and body weights were maintained. Elevation of ear thickness induced by PA treatment was rapidly diminished in the CMT- and FSC-treated groups, although there was no significant difference between the two groups. Furthermore, significant reduction of epidermal thickness was detected in both the PA+CMT- and PA+FSC-treated groups. However, IgE concentration and dermal thickness were reduced only by PA+FSC treatment, whereas PA+CMT treatment maintained levels comparable to PA+vehicle treatment. The number of infiltrated mast cells was higher in the PA+vehicle-treated group compared to the untreated control. Following CMT or FSC treatment, mast cell infiltration was slightly reduced, although the CMT-treated group showed greater cell numbers. These results indicate that FSC may significantly relieve the phenotypes of AD induced by PA treatment and should be considered as a potential candidate for AD therapy. PMID:23825483

  3. Involvement of inflammatory mediators in the airway responses to trimellitic anhydride in sensitized guinea-pigs.

    PubMed Central

    Hayes, J. P.; Lotvall, J. O.; Barnes, P. J.; Newman Taylor, A. J.; Chung, K. F.

    1992-01-01

    1. We examined the effect of various pharmacological agents on the acute bronchoconstrictor response and airway microvascular leakage in a model of guinea-pig sensitization to trimellitic anhydride (TMA) a cause of low molecular weight occupational asthma in man. 2. Guinea-pigs were given intradermal injections of 0.1 ml of 0.3% TMA in corn oil; 21-28 days later, anaesthetized guinea-pigs were challenged with TMA conjugated to guinea-pig albumin by tracheal instillation. Changes in lung resistance were measured and airway microvascular leakage was quantified by measuring the extravasation of Evans blue dye into the airway tissue. 3. Sensitized guinea-pig (n = 9 in each group) were pretreated with chlorpheniramine (2.5 mg kg-1, i.v.), WEB 2086 (10 micrograms kg-1, i.v.), BW 4AC (50 mg kg-1, i.p.), nedocromil sodium (2% aerosol for 60 s) or vehicle alone. 4. Pretreatment with chlorpheniramine inhibited both the acute bronchoconstrictor response and the increase in airway microvascular leakage. WEB 2086 and nedocromil sodium partially inhibited the bronchoconstrictor response but had no significant effect on airway microvascular leakage. BW 4AC caused a non-significant reduction of the bronchoconstrictor response and airway microvascular leakage. 5. These results indicate that both the bronchoconstrictor response and the airway microvascular response in this model of sensitization is mediated to a large extent by histamine. PAF but not 5-lipoxygenase products also partially mediates the bronchoconstrictor response but not the airway microvascular leakage. Nedocromil sodium partially inhibits the bronchoconstrictor response only. PMID:1382788

  4. Trimellitic anhydride-conjugated serum albumin activates rat alveolar macrophages in vitro

    PubMed Central

    Valstar, Dingena L; Schijf, Marcel A; Stelekati, Erietta; Nijkamp, Frans P; Bloksma, Nanne; Henricks, Paul AJ

    2006-01-01

    Background Occupational exposure to airborne low molecular weight chemicals, like trimellitic anhydride (TMA), can result in occupational asthma. Alveolar macrophages (AMs) are among the first cells to encounter these inhaled compounds and were previously shown to influence TMA-induced asthma-like symptoms in the Brown Norway rat. TMA is a hapten that will bind to endogenous proteins upon entrance of the body. Therefore, in the present study we determined if TMA and TMA conjugated to serum albumin induced the production of the macrophage mediators nitric oxide (NO), tumour necrosis factor (TNF), and interleukin 6 (IL-6) in vitro using the rat AM cell line NR8383 and primary AMs derived from TMA-sensitized and naïve Brown Norway rats. Methods Cells were incubated with different concentrations of TMA, TMA conjugated to bovine serum albumin (BSA), and BSA as a control for 24 h and the culture supernatant was analyzed for mediator content. Results TMA alone was not able to induce the production of mediators by NR8383 cells and primary AMs from sensitized and sham-treated rats. TMA-BSA, on the contrary, dose-dependently stimulated the production of NO, TNF, and IL-6 by NR8383 cells and of NO and TNF, but not IL-6, by primary AMs independent of sensitization. Conclusion Results suggest that although TMA is a highly reactive compound, conjugation to a suitable protein is necessary to induce mediator production by AMs. Furthermore, the observation that effects of TMA-BSA were independent of sensitization suggests involvement of an immunologically non-specific receptor. In the discussion it is argued that a macrophage scavenger receptor is a likely candidate. PMID:16796737

  5. Evaporative Derivatization of Phenols with 2-Sulfobenzoic Anhydride for Detection by MALDI-MS

    PubMed Central

    Yao, Yuanyuan; Wang, Poguang; Giese, Roger

    2014-01-01

    RATIONALE Phenols are an important class of analytes, for example as bioactive environmental contaminants. Towards a goal of improving their detection by MALDI-TOF-MS or MALDI-TOF/TOF-MS, we studied their derivatization with 2-sulfobenzoic anhydride (SBA). We chose SBA for this purpose since it is commercially available, inexpensive, and forms an anionic derivative. METHODS In selected conditions developed here for phenols, a reaction mixture of one or more of such compounds in acetonitrile containing SBA and 4-dimethylaminopyridine (DMAP) is evaporated to a solid, heated at 60°C for 1 h, redissolved in 50% acetonitrile containing matrix, spotted onto a MALDI target, and subjected to negative ion MALDI-TOF/TOF-MS. RESULTS While conventional (solution-phase) reaction of 4-phenylphenol (model analyte) with SBA and DMAP only gave a 47% yield of SBA-tagged 4-phenylphenol, evaporative derivatization as above gave a 96% yield, and 25 pmol (4.3 ng) of 4-phenylphenol could be detected in this way by MALDI-TOF/TOF-MS at S/N = 260, whereas even 1 nmol of the nonderivatized phenol was not detected in the absence of derivatization. A wide range of responses was observed when a mixture of 15 phenols was derivatized, with the higher responses coming from phenols with a pKa value above 9. Without derivatization, phenols with pKa values below 5 were the most readily detected. CONCLUSION Evaporative derivatization with SBA (a convenient reagent) can improve the detection of phenols with relatively high pKa values (above 9) by negative ion MALDI-TOF-MS, and accomplish this in the absence of post-derivatization reaction cleanup. PMID:24519828

  6. Role of mast cell in the late phase of contact hypersensitivity induced by trimellitic anhydride

    PubMed Central

    Chai, Ok Hee

    2015-01-01

    Mast cells are known as effector cells of IgE-mediated allergic responses, but role of mast cells in contact hypersensitivity (CHS) has been considered controversial. In this study, we investigated role of mast cell in trimellitic anhydride (TMA)-induced CHS. The mice were sensitized to TMA on the back and repeatedly challenged with TMA on the left ear at 1-week intervals. The ear after challenge showed biphasic responses. The repetition of TMA challenge shifted in time course of ear response and enlarged the extent of early and late phase reactions in proportion to the frequency of TMA challenges in C57BL/6 mice. In late phase reaction, peak of ear response by single challenge showed at 24 hours after challenge, but the peak by repeat challenges at 8 hours after the last challenge. Number of mast cells and eosinophils per unit area increased in proportion to frequency of TMA challenges. However, mast cell-deficient WBB6F1/J-KitW/KitW-v mice developed the late phase reaction without the early phase reaction. The repetition of TMA challenge shifted in time course of ear response and enlarged the extent of ear response and the infiltration of eosinophils. The magnitude of these responses observed according to the frequency of the TMA challenge in mast cell-deficient WBB6F1/J-KitW/KitW-v mice was significantly lower than that in C57BL/6 mice. Also TMA elicited mast cell degranulation and histamine release from rat peritoneal mast cells in a concentration-dependent manner. Conclusively, TMA induces the early and late phase reactions in CHS, and mast cells may be required for TMA-induced CHS. PMID:26770872

  7. Elucidation of substituted ester group position in octenylsuccinic anhydride modified sugary maize soluble starch.

    PubMed

    Ye, Fan; Miao, Ming; Huang, Chao; Lu, Keyu; Jiang, Bo; Zhang, Tao

    2014-12-03

    The octenylsuccinic groups in esterification-modified sugary maize soluble starches with a low (0.0191) or high (0.0504) degree of substitution (DS) were investigated by amyloglucosidase hydrolysis followed by a combination of chemical and physical analysis. The results showed the zeta-potential remained at approximately the same value regardless of excessive hydrolysis. The weight-average molecular weight decreased rapidly and reached 1.22 × 10(7) and 1.60 × 10(7) g/mol after 120 min for low-DS and high-DS octenylsuccinic anhydride (OSA) modified starch, respectively. The pattern of z-average radius of gyration as well as particle size change was similar to that of Mw, and z-average radius of gyration decreased much more slowly, especially for high-DS OSA starch. Compared to native starch, two characteristic absorption peaks at 1726.76 and 1571.83 cm(-1) were observed in FT-IR spectra, and the intensity of absorption peaks increased with increasing DS. The NMR results showed that OSA starch had several additional peaks at 0.8-3.0 ppm and a shoulder at 5.56 ppm for OSA substituents, which were grafted at O-2 and O-3 positions in soluble starch. The even distribution of OSA groups in the center area of soluble starch particle has been directly shown under CLSM. Most substitutions were located near branching points of soluble starch particles for a low-DS modified starch, whereas the substituted ester groups were located near branching points as well as at the nonreducing ends in OSA starch with a high DS.

  8. Therapeutic effect of ethyl acetate extract from Asparagus cochinchinensis on phthalic anhydride-induced skin inflammation

    PubMed Central

    Sung, Ji-Eun; Lee, Hyun-Ah; Kim, Ji-Eun; Go, Jun; Seo, Eun-Ji; Yun, Woo-Bin; Kim, Dong-Seob; Son, Hong-Joo; Lee, Chung-Yeoul; Lee, Hee-Seob

    2016-01-01

    Asparagus cochinchinensis has been used to treat various diseases including fever, cough, kidney disease, breast cancer, inflammatory disease and brain disease, while IL-4 cytokine has been considered as key regulator on the skin homeostasis and the predisposition toward allergic skin inflammation. However, few studies have investigated its effects and IL-4 correlation on skin inflammation to date. To quantitatively evaluate the suppressive effects of ethyl acetate extracts of A. cochinchinensis (EaEAC) on phthalic anhydride (PA)-induced skin inflammation and investigate the role of IL-4 during their action mechanism, alterations in general phenotype biomarkers and luciferase-derived signals were measured in IL-4/Luc/CNS-1 transgenic (Tg) mice with PA-induced skin inflammation after treatment with EaEAC for 2 weeks. Key phenotype markers including lymph node weight, immunoglobulin E (IgE) concentration, epidermis thickness and number of infiltrated mast cells were significantly decreased in the PA+EaEAC treated group compared with the PA+Vehicle treated group. In addition, expression of IL-1β and TNF-α was also decreased in the PA+EaEAC cotreated group, compared to PA+Vehicle treated group. Furthermore, a significant decrease in the luciferase signal derived from IL-4 promoter was detected in the abdominal region, submandibular lymph node and mesenteric lymph node of the PA+EaEAC treated group, compared to PA+Vehicle treated group. Taken together, these results suggest that EaEAC treatment could successfully improve PA-induced skin inflammation of IL-4/Luc/CNS-1 Tg mice, and that IL-4 cytokine plays a key role in the therapeutic process of EaEAC. PMID:27051441

  9. A New Process for Maleic Anhydride Synthesis from a Renewable Building Block: The Gas-Phase Oxidehydration of Bio-1-butanol.

    PubMed

    Pavarelli, Giulia; Velasquez Ochoa, Juliana; Caldarelli, Aurora; Puzzo, Francesco; Cavani, Fabrizio; Dubois, Jean-Luc

    2015-07-08

    We investigated the synthesis of maleic anhydride by oxidehydration of a bio-alcohol, 1-butanol, as a possible alternative to the classical process of n-butane oxidation. A vanadyl pyrophosphate catalyst was used to explore the one-pot reaction, which involved two sequential steps: 1) 1-butanol dehydration to 1-butene, catalysed by acid sites, and 2) the oxidation of butenes to maleic anhydride, catalysed by redox sites. A non-negligible amount of phthalic anhydride was also formed. The effect of different experimental parameters was investigated with chemically sourced 1-butanol, and the results were then confirmed by using genuinely bio-sourced 1-butanol. In the case of bio-1-butanol, however, the purity of the product remarkably affected the yield of maleic anhydride. It was found that the reaction mechanism includes the oxidation of butenes to crotonaldehyde and the oxidation of the latter to either furan or maleic acid, both of which are transformed to produce maleic anhydride.

  10. Determination of amines as pentafluoropropionic acid anhydride derivatives in biological samples using liquid chromatography and tandem mass spectrometry.

    PubMed

    Marand, Asa; Karlsson, Daniel; Dalene, Marianne; Skarping, Gunnar

    2004-06-01

    Determination of amines in biological samples as markers of exposure to the amines or the corresponding isocyanates is an important tool for industrial exposure assessment. In this study, a liquid chromatography and tandem mass spectrometry (LC-MS/MS) method for determination of amines in biological samples as perfluorofatty amides derivatives is presented. The method enables determination of diamines such as methylene diamine (MDA), toluene diamine (TDA), naphthalene diamine (NDA), hexamethylene diamine (HDA), isophorone diamine (IPDA), methylenedi(cyclohexylamine)(HMDA) and 4,4'-methylene-(2-chloroaniline)(MOCA) in human urine and plasma. The work-up procedure included hydrolysis of the biological samples with 3 M H(2)SO(4) at 100 degrees C for 16 h and extraction of the amines into toluene, where derivatisation of the amines with perfluorofatty acid anhydride was performed. Following removal of excess reagent and the acid formed and an exchange of solvent, the derivatives were analysed using gradient elution with an acetonitrile/water mobile phase composition and electrospray ionisation (ESI) with multiple reaction monitoring (MRM) of [M - H](-)-->[M - H - 120](-) or [119](-). Several perfluorofatty acid anhydrides were evaluated as derivatisation reagents, but the LC chromatographic properties of the pentafluoropropionic acid anhydride (PFPA) derivatives were favourable. Quantification of amine-PFPA derivatives was performed using deuterium labelled amine-PFPA derivatives as internals standards with good precision and linearity in the investigated range of 0-20 ng ml(-1) urine. The instrumental detection limits for the amine-PFPA derivatives were 0.2-3 fmol for MRM of [M - H](-)-->[119](-) and 0.3-8 fmol for [M - H](-)-->[M - H - 120](-). In 10 urine and 6 plasma samples from workers exposed to isocyanates, determination of TDA and MDA as PFPA derivatives was performed using LC-MS/MS and a reference GC-MS method. No significant difference between the two

  11. Polymer inflation

    NASA Astrophysics Data System (ADS)

    Hassan, Syed Moeez; Husain, Viqar; Seahra, Sanjeev S.

    2015-03-01

    We consider the semiclassical dynamics of a free massive scalar field in a homogeneous and isotropic cosmological spacetime. The scalar field is quantized using the polymer quantization method assuming that it is described by a Gaussian coherent state. For quadratic potentials, the semiclassical equations of motion yield a universe that has an early "polymer inflation" phase which is generic and almost exactly de Sitter, followed by an epoch of slow-roll inflation. We compute polymer corrections to the slow-roll formalism, and discuss the probability of inflation in this model using a physical Hamiltonian arising from time gauge fixing. We also show how in this model, it is possible to obtain a significant amount of slow-roll inflation from sub-Planckian initial data, hence circumventing some of the criticisms of standard scenarios. These results show the extent to which a quantum gravity motivated quantization method affects early universe dynamics.

  12. Design and synthesis of digitally encoded polymers that can be decoded and erased

    PubMed Central

    Roy, Raj Kumar; Meszynska, Anna; Laure, Chloé; Charles, Laurence; Verchin, Claire; Lutz, Jean-François

    2015-01-01

    Biopolymers such as DNA store information in their chains using controlled sequences of monomers. Here we describe a non-natural information-containing macromolecule that can store and retrieve digital information. Monodisperse sequence-encoded poly(alkoxyamine amide)s were synthesized using an iterative strategy employing two chemoselective steps: the reaction of a primary amine with an acid anhydride and the radical coupling of a carbon-centred radical with a nitroxide. A binary code was implemented in the polymer chains using three monomers: one nitroxide spacer and two interchangeable anhydrides defined as 0-bit and 1-bit. This methodology allows encryption of any desired sequence in the chains. Moreover, the formed sequences are easy to decode using tandem mass spectrometry. Indeed, these polymers follow predictable fragmentation pathways that can be easily deciphered. Moreover, poly(alkoxyamine amide)s are thermolabile. Thus, the digital information encrypted in the chains can be erased by heating the polymers in the solid state or in solution. PMID:26006165

  13. Self-healing antimicrobial polymer coating with efficacy in the presence of organic matter

    NASA Astrophysics Data System (ADS)

    Bastarrachea, Luis J.; Goddard, Julie M.

    2016-08-01

    A method to prepare a self-healing, antimicrobial polymer coating that retains efficacy against Escherichia coli O157:H7 in the presence of organic matter is reported. A coating composed of branched polyethyleneimine (PEI) and styrene maleic anhydride copolymer (SMA) was applied to a maleic anhydride functionalized polypropylene support. The chemistry of the polymer coating was designed to impart hydrophobicity due to the styrene subunits, intrinsic antimicrobial character (>99.9% reduction) from the cationic primary amine groups, and enhanced antimicrobial character (> 99.99% reduction) after chlorination of N-halamine forming groups. Antimicrobial effectiveness was demonstrated under conditions of increasing organic load. Up to 500 ppm horse serum, chlorinated coatings retained full antimicrobial character (>99.99% reduction). Even at 50,000 ppm of horse serum, the coating provided ∼90% reduction as prepared, and between ∼75% and ∼80% reduction in the form of N-halamines. Microscopy confirmed no evidence of bacterial adhesion on the coating surface. Finally, the coating exhibited self-healing properties after exposure to acid and alkaline solutions and restoration by heat, as confirmed through spectroscopy from the rebuilding of characteristic chemical bonds. Such robust antimicrobial polymer coatings with efficacy under conditions of increasing organic load may support reducing microbial cross-contamination in food and biomedical industries.

  14. Effect of polymer properties and adherend surfaces on adhesion. [titanium, aluminum

    NASA Technical Reports Server (NTRS)

    Dwight, D. W.; Counts, M. E.; Wightman, J. P.

    1975-01-01

    The surface properties associated with good adhesive joints were evaluated in terms of application of adhesive bonding in aerospace technology. The physical and chemical nature was determined of Ti and Al adherend surfaces after various surface treatments, and the effects on fracture surfaces of high temperature aging, and variations in amide, anhydride, and solvent during polymer synthesis. The effects were characterized of (1) high temperature during shear strength testing, (2) fiber-reinforced composites as adherends, (3) acid/base nature of adherends, (4) aluminum powder adhesive filler, and (5) bonding pressure.

  15. Synthesis of comb-like copolymers from renewable resources: Itaconic anhydride, stearyl methacrylate and lactic acid

    NASA Astrophysics Data System (ADS)

    Shang, Shurui

    The synthesis and properties of comb-like copolymers and ionomers derived from renewable resources: itaconic anhydride (ITA), stearyl methacrylate (SM) and lactic acid (LA) are described. The copolymers based on ITA and SM (ITA-SM) were nearly random with a slight alternating tendency. The copolymers exhibited a nanophase-separated morphology, with the stearate side-chains forming a bilayer, semi-crystalline structure. The crystalline side-chains suppressed molecular motion of the main-chain, so that a glass transition temperature (Tg) was not resolved unless the ITA concentration was sufficiently high so that Tg > the melting point (Tm). The softening point and modulus of the copolymers increased with the increasing ITA concentration, but the thermal stability decreased. The ITA moiety along the main chain of the copolymers was neutralized with metal acetates to produce Na-, Ca- and Zn- random ionomers with comb-like architectures. In general, the incorporation of the ionic groups increased the Tg and suppressed the crystallinity of the side-chain packing. Ionomers with high SM side-chain density had two competing driving forces for self-assembled nano-phase separation: ionic aggregation and side-chain crystalline packing. Upon neutralization, a morphological transition from semi-crystalline lamella to spherical ionic aggregation was observed by small angle X-ray scattering (SAXS) analysis and transmission electron microscopy (TEM). Thermomechanical analysis revealed an increasing resistance to penetration deformation with an increasing degree of neutralization and an apparent rubbery plateau was observed above Tg. A controlled transesterification of PLA in glassware was an effective way to prepare a methacrylate functionalized PLA macromonomer with controlled molecular weight, which was used to synthesize a variety of copolymers. The copolymerization of this functionalized PLA macromonomer with ITA totally suppressed the side-chain crystallinity for the PLA chain

  16. Autoimmune response in MRL+/+ mice following treatment with dichloroacetyl chloride or dichloroacetic anhydride

    SciTech Connect

    Cai Ping; Koenig, Rolf; Khan, M. Firoze; Qiu, Suimin; Kaphalia, Bhupendra S.; Ansari, G.A.S. . E-mail: sansari@utmb.edu

    2006-10-15

    Dichloroacetyl chloride (DCAC) is formed from trichloroethene (TCE), which is implicated in inducing/accelerating autoimmune response. Due to its potent acylating activity, DCAC may convert proteins to neo-antigens and thus could induce autoimmune responses. Dichloroacetic anhydride (DCAA), which is a similar acylating agent, might also induce autoimmune responses. To evaluate if chloroacylation plays a role in the induction of autoimmunity, we have measured the autoimmune responses following treatment with DCAC or DCAA in autoimmune-prone MRL+/+ mice. Five-week-old female mice were injected intraperitoneally (twice weekly) with 0.2 mmol/kg of DCAC or DCAA in corn oil for 6 weeks. Total serum IgG, IgG1, and IgE levels were significantly increased in DCAC-treated mice as compared to controls. These increases corresponded with increases in DCAC-specific IgG and IgG1 levels. Total serum IgM was decreased in both DCAC- and DCAA-treated mice. Antinuclear antibodies, measured as an indication of systemic autoimmune responses, were increased in both DCAC- and DCAA-treated mice. Of eight Th1/Th2 cytokines measured in the serum, only IL-5 was significantly decreased in both treatment groups. The cytokine secretion patterns of splenic lymphocytes after stimulation with antibodies against CD3 (T cell receptor-mediated signal) and CD28 (costimulatory signal) differed between treatment and control groups. Levels of IL-1, IL-3, IL-6, IFN-{gamma}, G-CSF, and KC were higher in cultures of stimulated splenocytes from either DCAC- or DCAA-treated mice than from controls. The level of IL-17 was only increased in cultures from DCAC-treated mice. Increased lymphocytic populations were found in the red pulp of spleens following treatment with either DCAC or DCAA. In addition, thickening of the alveolar septa in the lungs of DCAC- or DCAA-treated mice was observed. The lung histopathology in exposed mice was consistent with the symptomology observed in welders exposed to DCAC

  17. Antimicrobial polymers.

    PubMed

    Jain, Anjali; Duvvuri, L Sailaja; Farah, Shady; Beyth, Nurit; Domb, Abraham J; Khan, Wahid

    2014-12-01

    Better health is basic requirement of human being, but the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern science. Infections by pathogenic microorganisms are of great concern in many fields such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications (e.g., water purification systems, textiles, food packaging and storage, major or domestic appliances etc.) Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Recently, they gained considerable interest for both academic research and industry and were found to be better than their small molecular counterparts in terms of enhanced efficacy, reduced toxicity, minimized environmental problems, resistance, and prolonged lifetime. Hence, efforts have focused on the development of antimicrobial polymers with all desired characters for optimum activity. In this Review, an overview of different antimicrobial polymers, their mechanism of action, factors affecting antimicrobial activity, and application in various fields are given. Recent advances and the current clinical status of these polymers are also discussed.

  18. Polymer solutions

    DOEpatents

    Krawczyk, Gerhard Erich; Miller, Kevin Michael

    2011-07-26

    There is provided a method of making a polymer solution comprising polymerizing one or more monomer in a solvent, wherein said monomer comprises one or more ethylenically unsaturated monomer that is a multi-functional Michael donor, and wherein said solvent comprises 40% or more by weight, based on the weight of said solvent, one or more multi-functional Michael donor.

  19. Diclofenac sodium (DS) loaded bioerodible polymer based constructs

    NASA Astrophysics Data System (ADS)

    Piras, M.; Chiellini, F.; Nikkola, L.; Ashammakhi, N.; Chiellini, E.

    2008-02-01

    Pain is a prevalent problem that can raise morbidity of patients. Pain killer releasing biodegradable materials have been developed by using different techniques and biomaterials. The objective of the current study is to evaluate the use of a new bioerodible polymer for release of diclofenac sodium (DS). 1-butanol hemiester poly(maleic anhydride-alt-2-methoxyethyl vinyl ether) (PAM14) was prepared in the university of Pisa and selected as polymer of choice for the study. Polymer solutions of 5-10% (in ethanol or in acetic acid) were prepared, half of them containing 2% DS. The solutions were then electrospun to produce nanomats that were subsequently characterized using SEM. Fiber diameter was 160 nm 1 μm. Increasing polymer concentration increased the size of the fibers but reduced the number of beads (with or without DS). In the specimens obtained from acetic acid solution, the addition of DS resulted in a reduction in fiber diameter and an increase in the inter-bead distance. Corresponding ethanol solutions gave more homogeneous specimens than did acetic acid, having a lower number of beads. With the addition of DS a reduction in fiber diameter was observed for the acetic acid specimens. However, in ethanol, adding DS resulted in increased fiber diameter. Accordingly, it can be concluded that it is feasible to develop electrospun diclofenac releasing bioerodible nanostructures that have potential use in pain management. Their further evaluation is however, needed both in vitro and in vivo.

  20. Modelling of crystal structure of cis-1,2,3,6 and 3,4,5,6-tetrahydrophthalic anhydrides using lattice energy calculations.

    PubMed

    Fredj, A Ben; Day, G M

    2015-08-01

    Lattice energy calculations using a model potential were performed to model the crystal structures of cis-1,2,3,6- and 3,4,5,6-tetrahydrophthalic (THP) anhydrides. The optimized molecular models using the DFT method at the B3LYP/6-31G** level were found consistent with the available experimental evidence and allowed all differences observed in crystal packing between cis-1,2,3,6- and 3,4,5,6-THP anhydrides to be reproduced. Calculations provide evidence for the presence of dipole-dipole C=O⋯C=O intermolecular interactions and support the idea that the molecules distort from their ideal geometries, improving packing in both crystals. The search for minima in the lattice energy of both crystals amongst the more common space groups with Z' = 1, using a simulated annealing crystal structure prediction procedure followed by lattice energy minimization showed that the observed structure of 3,4,5,6-THP anhydride (Z' = 2) is the thermodynamically most stable, and allowed us to justify why 3,4,5,6-THP anhydride crystallizes in such a complex structure with 16 molecules in the unit cell. The computational model was successful in predicting the second observed form at 173 K for cis-1,2,3,6-THP anhydride as a polymorph, and could predict several hypothetical structures with Z' = 1 that appear competitive with the observed structures. The results of phonon estimates of zero point intermolecular vibrational energy and entropy suggest that crystal structures of cis-1,2,3,6-THP anhydride cannot be predicted solely on the basis of lattice energy; factors other than thermodynamics favor the observed structures.

  1. Design of a multi-dopamine-modified polymer ligand optimally suited for interfacing magnetic nanoparticles with biological systems.

    PubMed

    Wang, Wentao; Ji, Xin; Na, Hyon Bin; Safi, Malak; Smith, Alexandra; Palui, Goutam; Perez, J Manuel; Mattoussi, Hedi

    2014-06-03

    We have designed a set of multifunctional and multicoordinating polymer ligands that are optimally suited for surface functionalizing iron oxide and potentially other magnetic nanoparticles (NPs) and promoting their integration into biological systems. The amphiphilic polymers are prepared by coupling (via nucleophilic addition) several amine-terminated dopamine anchoring groups, poly(ethylene glycol) moieties, and reactive groups onto a poly(isobutylene-alt-maleic anhydride) (PIMA) chain. This design greatly benefits from the highly efficient and reagent-free one-step reaction of maleic anhydride groups with amine-containing molecules. The availability of several dopamine groups in the same ligand greatly enhances the ligand affinity, via multiple coordination, to the magnetic NPs, while the hydrophilic and reactive groups promote colloidal stability in buffer media and allow subsequent conjugation with target biomolecules. Iron oxide nanoparticles ligand exchanged with these polymer ligands have a compact hydrodynamic size and exhibit enhanced long-term colloidal stability over the pH range of 4-12 and in the presence of excess electrolytes. Nanoparticles ligated with terminally reactive polymers have been easily coupled to target dyes and tested in live cell imaging with no measurable cytotoxicity. Finally, the resulting hydrophilic nanoparticles exhibit large and size-dependent r2 relaxivity values.

  2. Increased oral bioavailability of paclitaxel by its encapsulation through complex formation with cyclodextrins in poly(anhydride) nanoparticles.

    PubMed

    Agüeros, M; Zabaleta, V; Espuelas, S; Campanero, M A; Irache, J M

    2010-07-01

    The aim of this work was to study the oral bioavailability in rats of paclitaxel (PTX) when encapsulated as a complex with cyclodextrins in poly(anhydride) nanoparticles (NP). For this purpose three different cyclodextrins were selected: beta-cyclodextrin (CD), 2-hydroxypropyl-beta-cyclodextrin (HPCD) and 6-monodeoxy-6-monoamino-beta-cyclodextrin (NHCD). A single dose of 10mg paclitaxel per kg body weight as PTX-cyclodextrin nanoparticles was used. Plasma curves were characterised by a plateau of paclitaxel concentration close to the C(max) from T(max) till 24h post-administration. For PTX-CD NP and PTX-HPCD NP, these sustained levels of the anticancer drug were found to be between 27 and 33-fold higher than the reported value of drug activity whereas the relative oral bioavailability of paclitaxel was calculated to be higher than 80%. These facts would be directly related with a synergistic effect obtained by the combination of the bioadhesive properties of poly(anhydride) nanoparticles and the inhibitory effect of cyclodextrins on the activity of P-glycoprotein and cythocrome P450.

  3. Anhydride functionalised calcium ferrite nanoparticles: a new selective magnetic material for enrichment of lead ions from water and food samples.

    PubMed

    Pirouz, Mojgan Jafari; Beyki, Mostafa Hossein; Shemirani, Farzaneh

    2015-03-01

    In this research a sonochemistry route for manufacture of uniform nanocrystalline CaFe2O4 and its anhydride functionalisation were reported. The potential of raw and modified material as a magnetically separable sorbent in selective enrichment of lead ions from water and food samples is outlined. This material was characterised using FT-IR, XRD, SEM and VSM techniques. The SEM and VSM results indicated that the calcium ferrite nanoparticles are sphere-like particles possessing superparamagnetic properties with an average diameter of 40 nm. Various analytical parameters, including pH, contact time, type and concentration of eluent, adsorption capacity, sample volume and interference of ions, were optimised. Following a modification by anhydride, calcium ferrite selectivity toward lead ions was raised more than twofold compared to the unmodified nanoparticles. Finally a pre-concentration procedure was applied for determination of trace Pb(II) in canned tuna fish, canned tomato paste, parsley, milk and well-water samples with satisfactory results.

  4. Degradable, pH-sensitive, membrane-destabilizing, comb-like polymers for intracellular delivery of nucleic acids.

    PubMed

    Lin, Yen-Ling; Jiang, Guohua; Birrell, Lisa K; El-Sayed, Mohamed E H

    2010-09-01

    This report describes the design and synthesis of a new series of degradable, pH-sensitive, membrane-destabilizing, comb-like polymers that can enhance the intracellular delivery of therapeutic nucleic acids. These comb-like polymers are based on a diblock polymer backbone where the first block is a copolymer of pH-sensitive ethyl acrylic acid (EAA) monomers and hydrophobic butyl methacrylate (BMA) or hexyl methacrylate monomers. The second block is a homopolymer of N-acryloxy succinimide (NASI) or ss-benzyl l-aspartate N-carboxy-anhydride (BLA-NCA) monomers, which are functionalized to allow controlled grafting of hydrophobic HMA and cationic trimethyl aminoethyl methacrylate (TMAEMA) copolymers via acid-labile hydrazone linkages. These comb-like polymers displayed high hemolytic activity in acidic solutions, which increased with the increase in polymer concentration. All comb-like polymers degraded into small fragments upon incubation in an acidic solution (pH 5.8) due to hydrolysis of the hydrazone linkages connecting the hydrophobic/cationic grafts to the polymer backbone. Comb-like polymers successfully complexed anti-GAPDH siRNA molecules into serum- and nuclease-stable particles, which successfully silenced GAPDH expression at both the mRNA and protein levels. These results collectively indicate the potential of these new comb-like polymers to serve as vehicles for effective intracellular delivery of therapeutic nucleic acids.

  5. Advanced Polymer

    NASA Technical Reports Server (NTRS)

    1992-01-01

    In the mid-1980's, Langley developed a polyimide sulfone, combining desirable properties of two classes of polymers. Composites and other products made from polyimide sulfone can be used with solvents and corrosive fluids, are light weight, low cost and can be easily fabricated for a wide range of industrial uses. High Technology Systems, Inc. obtained a license for the polymer and was awarded a Small Business Innovation Research (SBIR) contract for development in a powder form. Although its principal use is as a matrix resin for composites, the material can also be used as a high temperature structural adhesive for aircraft structures and as a coating for protection from heat and radiation for electronic components.

  6. Theoretical Polymers.

    DTIC Science & Technology

    1976-10-07

    for the correlation length of 3/4, while 0.72 is observed. Then followed several talks on the expansion coefficient a, the virial coefficients and...calculation of the virial coefficient and c~2. These quantities can be considered merely a testing ground for the use of this method to polymer...the second viria]. coefficient , A2, to be zero and the intrinsic viscosity dependent on~VW for polystyrene mole-cular weights between 33,000 and one

  7. Phthalocyanine polymers

    NASA Technical Reports Server (NTRS)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    A method of forming 4,4',4'',4''' -tetraamino phthalocyanines involves reducing 4,4',4'',4''' -tetranitro phthalocyanines, polymerizing the metal tetraamino phthalocyanines with a tetracarboxylic dianhydride (preferably aromatic) or copolymerizing with a tetracarboxylic dianhydride and a diamine (preferably also aromatic) to produce amic acids which are then dehydrocyclized to imides. Thermally and oxidatively stable polymers result which form tough, flexible films, varnishes, adhesives, and fibers.

  8. Plasma deposition of polymer composite films incorporating nanocellulose whiskers

    NASA Astrophysics Data System (ADS)

    Samyn, P.; Airoudj, A.; Laborie, M.-P.; Mathew, A. P.; Roucoules, V.

    2011-11-01

    In a trend for sustainable engineering and functionalization of surfaces, we explore the possibilities of gas phase processes to deposit nanocomposite films. From an analysis of pulsed plasma polymerization of maleic anhydride in the presence of nanocellulose whiskers, it seems that thin nanocomposite films can be deposited with various patterns. By specifically modifying plasma parameters such as total power, duty cycle, and monomer gas pressure, the nanocellulose whiskers are either incorporated into a buckled polymer film or single nanocellulose whiskers are deposited on top of a polymeric film. The density of the latter can be controlled by modifying the exact positioning of the substrate in the reactor. The resulting morphologies are evaluated by optical microscopy, AFM, contact angle measurements and ellipsometry.

  9. Periodic Polymers

    NASA Astrophysics Data System (ADS)

    Thomas, Edwin

    2013-03-01

    Periodic polymers can be made by self assembly, directed self assembly and by photolithography. Such materials provide a versatile platform for 1, 2 and 3D periodic nano-micro scale composites with either dielectric or impedance contrast or both, and these can serve for example, as photonic and or phononic crystals for electromagnetic and elastic waves as well as mechanical frames/trusses. Compared to electromagnetic waves, elastic waves are both less complex (longitudinal modes in fluids) and more complex (longitudinal, transverse in-plane and transverse out-of-plane modes in solids). Engineering of the dispersion relation between wave frequency w and wave vector, k enables the opening of band gaps in the density of modes and detailed shaping of w(k). Band gaps can be opened by Bragg scattering, anti-crossing of bands and discrete shape resonances. Current interest is in our group focuses using design - modeling, fabrication and measurement of polymer-based periodic materials for applications as tunable optics and control of phonon flow. Several examples will be described including the design of structures for multispectral band gaps for elastic waves to alter the phonon density of states, the creation of block polymer and bicontinuous metal-carbon nanoframes for structures that are robust against ballistic projectiles and quasi-crystalline solid/fluid structures that can steer shock waves.

  10. In situ compatibilizer-reinforced interface between a flexible polymer (a functionalized polypropylene) and a rodlike polymer (a thermotropic liquid crystalline polymer).

    PubMed

    Seo, Yongsok; Ninh, Tran Hai; Hong, Soon Man; Kim, Sehyun; Kang, Tae Jin; Kim, Hansung; Kim, Jinyeol

    2006-03-28

    We present an investigation of the interfacial reinforcement between a flexible folded-chain polymer (functionalized polypropylene-maleic anhydride-grafted polypropylene, MAPP) and a rodlike polymer (a themotropic liquid crystalline polymer, TCLP - poly(ester amide)). Fracture toughness was measured using an asymmetric double-cantilever beam test (ADCB). High fracture toughness at the bonding temperature of 200 degrees C indicates that a chemical reaction has occurred at the interface to provide a strong interaction between MAPP and TLCP. Despite the higher modulus of TLCP, the fracture was propagated in the TLCP phase because of inherent TLCP domain structure. An analysis on the locus of failure revealed that at constant bonding temperature the fracture toughness between MAPP and TLCP was influenced not only by the bonding temperature but also by the bonding time. The fracture toughness increased with the bonding temperature until 200 degrees C was reached and then decreased at higher bonding temperature. The fracture toughness increased with annealing time until it reached a plateau value. We ascribe the dependence of the fracture toughness on the bonding time to the progressive occurrence of two different failure mechanisms, adhesive failure and cohesive failure. The adhesive strength increased with bonding temperature whereas the cohesive strength decreased because of weaker adhesion between TLCP crystalline domains. The dependence of fracture toughness on bonding time was explained in terms of the TLCP crystalline domain structure.

  11. Efficacy of measures of hygiene in workers sensitised to acid anhydrides and the influence of selection bias on the results

    PubMed Central

    Drexler, H.; Schaller, K. H.; Nielsen, J.; Weber, A.; Weihrauch, M.; Welinder, H.; Skerfving, S.

    1999-01-01

    OBJECTIVES: Organic acid anhydrides are potential sensitisers and cause occupational airway diseases. In an intervention study the efficacy of measures of hygiene at the workplace and possible selection bias were investigated. METHODS: A first investigation with 110 workers exposed to hexahydrophthalic acid anhydride (HHPA) and methyltetrahydrophthalic acid anhydride (MTHPA) was carried out in July 1991. The results (skin prick test, specific serum IgE) showed that 20 people were sensitised, and in a challenge test the clinical relevance of the sensitisation was confirmed in six subjects. In December 1991, the hygiene conditions at the plant were improved. In November 1995 a second investigation of 84 people was performed (anamnesis, skin prick test, specific IgE, spirometry, and ambient and biological monitoring). The 27 people who had left the plant in the meantime were asked their reasons for leaving. RESULTS: The relative risk of people sensitised in 1991 of leaving the plant between 1991 and 1995 was 2.6 (95% confidence interval (95% CI) 1.4 to 4.9) compared with people without any sign of sensitisation. The percentage of people identified as sensitised in 1991, who were still working at the plant and came to the second investigation, was higher than for people without evidence of sensitisation (10/10 v 47/73; p < 0.05). In all the 10 sensitised people in 1991 the findings of the first investigation were confirmed in 1995. The rate of sensitisation in 1995 was 21%. None of the six people employed after 1991 showed evidence of sensitisation. Of the six people with clinically relevant sensitisation confirmed by a challenge test in 1991, five were still at their workplace. From 1991 they were only exposed to MTHPA at a reduced concentration (< 0.5-36 micrograms/m3 in 1995). All of them reported fewer symptoms than in 1991. No signs of bronchial obstruction were detected by spirometry at the workplace. CONCLUSIONS: In cross sectional studies there is a selection

  12. Morphology and phase controlled cobalt nanostructures in magnetic polypropylene nanocomposites: the role of alkyl chain-length in maleic anhydride grafted polypropylene.

    PubMed

    He, Qingliang; Yuan, Tingting; Luo, Zhiping; Haldolaarachchige, Neel; Young, David P; Wei, Suying; Guo, Zhanhu

    2013-04-04

    A novel function of maleic anhydride grafted polypropylene (PP) with different backbone chain-lengths was demonstrated, i.e., in controlling the cobalt morphologies (dispersed polyhedral vs. assembled chain nanostructure), crystalline structures (ε- vs. β-phase), and magnetic property (242 vs. 808 Oe) in the synthesized magnetic PP nanocomposites.

  13. 40 CFR 721.3635 - Octadecanoic acid, ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Octadecanoic acid, ester with 1,2..., ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as octadecanoic acid,...

  14. 40 CFR 721.3635 - Octadecanoic acid, ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Octadecanoic acid, ester with 1,2..., ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as octadecanoic acid,...

  15. An atom-economic approach to carboxylic acids via Pd-catalyzed direct addition of formic acid to olefins with acetic anhydride as a co-catalyst.

    PubMed

    Wang, Yang; Ren, Wenlong; Shi, Yian

    2015-08-21

    An effective Pd-catalyzed hydrocarboxylation of olefins using formic acid with acetic anhydride as a co-catalyst is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under mild reaction conditions without the use of toxic CO gas.

  16. Is the 2,3-carbon-carbon bond of indole really inert to oxidative cleavage by Oxone?--synthesis of isatoic anhydrides from indoles.

    PubMed

    Nelson, Amber C; Kalinowski, Emily S; Czerniecki, Nikolas J; Jacobson, Taylor L; Grundt, Peter

    2013-11-21

    A recent report has indicated that the oxidizing agent Oxone does not possess the ability to cleave the 2,3-carbon-carbon bond of indole. Work in our laboratory shows that this is not the case. Indole and a variety of aryl ring substituted derivatives readily react to form synthetically important isatoic anhydrides.

  17. Biotin-conjugated N-methylisatoic anhydride: a chemical tool for nucleic acid separation by selective 2'-hydroxyl acylation of RNA.

    PubMed

    Ursuegui, S; Chivot, N; Moutin, S; Burr, A; Fossey, C; Cailly, T; Laayoun, A; Fabis, F; Laurent, A

    2014-06-01

    An isatoic anhydride derivative conjugated to a biotin and a disulfide linker was specifically designed for the separation of nucleic acids. Starting from a DNA-RNA mixture, a selective 2'-hydroxyl acylation of RNAs followed by capture with streptavidin-coated magnetic beads and cleavage of the disulfide led to elution of RNAs.

  18. Characterization of maleic acid/anhydride copolymer films by low-rate dynamic liquid-fluid contact angle measurements using axisymmetric drop shape analysis.

    PubMed

    Uhlmann, Petra; Skorupa, Sebastian; Werner, Carsten; Grundke, Karina

    2005-07-05

    Thin films of alternating maleic acid/anhydride copolymers (poly(octadecene-alt-maleic acid/anhydride), POMA; poly(propene-alt-maleic acid/anhydride), PPMA; poly(styrene-alt-maleic acid/anhydride), PSMA) were studied to unravel the influence of the comonomer characteristics in the backbone on the surface-energetic properties of the copolymer films in the dry state and in contact with aqueous solutions. Water contact angle measurements revealed a graduation of the wettability of the dry hydrolyzed and annealed copolymer films that was dependent on the comonomer unit. It ranged from moderately hydrophilic (PPMA, annealed gamma(sv) = 39.9 mJ/m2) to very hydrophobic (POMA, annealed, gamma(sv) = 18.4 mJ/m2) surfaces. Liquid-fluid contact angle measurements using captive air bubbles were performed in different aqueous media (pure water, phosphate-buffered saline, and 10(-)(3) M KCl of two different pH values (pH = 3 and pH = 10) to study the copolymer films in their hydrated states relevant for biointerfacial phenomena. It was found that the graduation of the wettability of the copolymer films in the dry state is overall maintained upon immersion in aqueous solutions. The dependence of the wettability on the pH value of the aqueous medium could be related to the (de)protonation of the carboxylic groups.

  19. Asymmetric synthesis of the HMG-CoA reductase inhibitor atorvastatin calcium: an organocatalytic anhydride desymmetrization and cyanide-free side chain elongation approach.

    PubMed

    Chen, Xiaofei; Xiong, Fangjun; Chen, Wenxue; He, Qiuqin; Chen, Fener

    2014-03-21

    An efficient asymmetric synthesis of atorvastatin calcium has been achieved from commercially available diethyl 3-hydroxyglutarate through a novel approach that involves an organocatalytic enantioselective cyclic anhydride desymmetrization to establish C(3) stereogenicity and cyanide-free assembly of C7 amino type side chain via C5+C2 strategy as the key transformations.

  20. SELECTIVE HYDROGENATION OF MALEIC ANHYDRIDE TO Y-BUTROLACTONE OVER PD/AL2O3 CATALYST USING SUPERCRITICAL CARBON DIOXIDE MEDIUM

    EPA Science Inventory

    Hydrogenation of maleic anhydride to g-butyrolactone over Pd/Al2O3 catalyst under supercritical carbondioxide medium

    Unnikrishnan R. Pillai and Endalkachew Sahle-Demessie
    National Risk Management Research laboratory (NRMRL), Clean Processes Branch, MS 443, United States...

  1. Synthesis of both enantiomers of hemiesters by enantioselective methanolysis of meso cyclic anhydrides catalyzed by alpha-amino acid-derived chiral thioureas.

    PubMed

    Manzano, Rubén; Andrés, José M; Muruzábal, María-Dolores; Pedrosa, Rafael

    2010-08-06

    Both ureas and thioureas derived from L- or D-valine act as bifunctional organocatalysts able to induce the enantioselective alcoholysis of mono-, bi-, and tricyclic meso anhydrides. The desymmetrization occurs in near quantitative yields and excellent enantiomeric ratios (up to >99:<1) under low catalyst loading. Both enantiomers of the hemiesters can be directly obtained by changing the configuration of the catalyst.

  2. Reaction of dimethoxycarbene-DMAD zwitterion with 1,2-diones and anhydrides: a novel synthesis of highly substituted dihydrofurans and spirodihydrofurans.

    PubMed

    Nair, Vijay; Deepthi, Ani; Poonoth, Manojkumar; Santhamma, Bindu; Vellalath, Sreekumar; Babu, Beneesh Pattoorpady; Mohan, Resmi; Suresh, Eringathodi

    2006-03-17

    The zwitterion formed by the reaction of dimethoxycarbene and DMAD adds efficiently to one of the carbonyl groups of 1,2-dicarbonyl compounds and anhydrides to generate dihydrofurans and spirodihydrofurans in good yields. In many cases, the carbene inserts into the C-C bond of the dione to yield masked vicinal tricarbonyl systems.

  3. Hyperbranched polymer films and dendrimers: Their chemistry and applications

    NASA Astrophysics Data System (ADS)

    Zhao, Mingqi

    The research in this dissertation examines the chemistry and applications of dendritic polymers; specifically, hyperbranched polymer thin films and dendrimers. We examined hyperbranched, fluorinated and unfluorinated poly(acrylic acid) (PAA) films on gold substrates, poly(amidoamine) (PAMAM) dendrimer monolayers and dendrimer-alkanethiol mixed monolayers on gold substrates, PAMAM dendrimer/poly(anhydride) and poly(iminopropane-1,3-diyl) (Cascade) dendrimer/poly(anhydride) multilayer films on silicon, gold, and aluminum substrates, PAMAM dendrimer/metal-ion composites, and PAMAM dendrimer-encapsulated metal nanoclusters in solution and on electrode surfaces. Hyperbranched PAA films have pH-dependent blocking abilities: at low pH PAA films effectively passivate Au electrodes while at high pH they are open and permeable. Fluorinated PAA films are far less permeable at any pH. Dendrimers ranging from generation 4 to 8 (G4--G8) can form highly stable and nearly close-packed monolayers and mixed monolayers with hexadecanethiol (C16SH) on surfaces. Moreover, dendrimers embedded within C16SH can act as gates of molecular dimension that control intradendrimer mass transfer of ions. Dendrimer/poly(anhydride) multilayers on surfaces were synthesized and their permeability was investigated. These composite membranes exhibit fully reversible, pH-switchable permselectivity for both cationic and anionic probe molecules because of their pH-dependent electrostatic properties. After heating, such films become highly blocking over the pH range studied due to thermally induced interdendrimer imidization, and other reactions. Finally, we show that PAMAM dendrimers can act first as templates for the preparation of transition-metal nanoclusters, and subsequently as stabilizers. Dendrimers quantitatively complex many transition-metal ions, including Cu 2+, Pt2+, Pd2+, Ru3+, and Ni2+, within their interiors. Chemical reduction of such nanocomposites results in formation of dendrimer

  4. Jeffamine® based polymers as highly conductive polymer electrolytes and cathode binder materials for battery application

    NASA Astrophysics Data System (ADS)

    Aldalur, Itziar; Zhang, Heng; Piszcz, Michał; Oteo, Uxue; Rodriguez-Martinez, Lide M.; Shanmukaraj, Devaraj; Rojo, Teofilo; Armand, Michel

    2017-04-01

    We report a simple synthesis route towards a new type of comb polymer material based on polyether amines oligomer side chains (i.e., Jeffamine® compounds) and a poly(ethylene-alt-maleic anhydride) backbone. Reaction proceeds by imide ring formation through the NH2 group allowing for attachment of side chains. By taking advantage of the high configurational freedoms and flexibility of propylene oxide/ethylene oxide units (PO/EO) in Jeffamine® compounds, novel polymer matrices were obtained with good elastomeric properties. Fully amorphous solid polymer electrolytes (SPEs) based on lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and Jeffamine®-based polymer matrices show low glass transition temperatures around -40 °C, high ionic conductivities and good electrochemical stabilities. The ionic conductivities of Jeffamine-based SPEs (5.3 × 10-4 S cm-1 at 70 °C and 4.5 × 10-5 S cm-1 at room temperature) are higher than those of the conventional SPEs comprising of LiTFSI and linear poly(ethylene oxide) (PEO), due to the amorphous nature and the high concentration of mobile end-groups of the Jeffamine-based polymer matrices rather than the semi-crystalline PEO The feasibility of Jeffamine-based compounds in lithium metal batteries is further demonstrated by the implementation of Jeffamine®-based polymer as a binder for cathode materials, and the stable cycling of Li|SPE|LiFePO4 and Li|SPE|S cells using Jeffamine-based SPEs.

  5. The effect of chemical modification with pyromellitic anhydride on structure, function, and thermal stability of horseradish peroxidase.

    PubMed

    Hassani, Leila

    2012-06-01

    The stability of enzymes remains a critical issue in biotechnology. Compared with the strategies for obtaining stable enzymes, chemical modification is a simple and effective technique. In the present study, chemical modification of horseradish peroxidase (HRP) was carried out with pyromellitic anhydride. HRP has achieved a prominent position in the pharmaceutical, chemical, and biotechnological industries. In this study, the effect of chemical modification on thermal stability, structure, and function of the enzyme was studied by fluorescence, circular dichroism, and absorbance measurements. The results indicated a decrease in compactness of the structure and a considerable enhancement in thermal stability of HRP below 60 °C. It seems the charge replacement and introduction of the bulky group bring about the observed structural and the functional changes.

  6. Recovery of uranium(VI) from aqueous solution by 2-picolylamine functionalized poly(styrene-co-maleic anhydride) resin.

    PubMed

    Liu, Shudi; Yang, Ying; Liu, Tonghuan; Wu, Wangsuo

    2017-07-01

    A 2-picolylamine functionalized poly(styrene-co-maleic anhydride) resin was synthesized and characterized by FT-IR, elemental analysis, SEM and XPS. To recover uranium from aqueous solution, the influence factors such as pH values, contact time, temperature and initial uranium concentration were optimized. Adsorption kinetics fitted well with the pseudo-second-order model, whereas adsorption isotherm matched well with the Langmuir isothermal adsorption model, with the maximum sorption capacity of 518.39mgg(-1) at pH 5.30 and 298K. The uptake of uranium could be implied in 0.01M coexisted ions environment. Besides, the resin could be regenerated by 0.1M HNO3 and repeatedly utilized in circles. The study proved that the resin has potential application prospects for disposal of uranium(VI).

  7. Modification of pineapple peel fibre with succinic anhydride for Cu2+, Cd2+ and Pb2+ removal from aqueous solutions.

    PubMed

    Hu, Xiuyi; Zhao, Mouming; Song, Guosheng; Huang, Huihua

    2011-01-01

    Research on chemical modification of pineapple peel fibre with succinic anhydride was carried out to create a novel adsorbent for Cu2+, Cd2+ and Pb2+ removal from aqueous solution. After pretreatment with iso-propyl alcohol and NaOH, pineapple peel fibre was modified via reaction with succinic anhydride for introduction of carboxylic functional groups. The modified pineapple peel fibre was characterized with Fourier transform infrared (FTIR) spectroscopy and evaluated for its adsorptive ability for Cu2+, Cd2+ and Pb2+ from synthetic metal solutions. The FTIR analysis proved the introduction of carboxylic functional groups in the backbone of the modified pineapple peel fibre. The modified pineapple peel fibre showed higher adsorptive capacity for Cu2+, Cd2+ and Pb2+ compared with raw pineapple peel and pineapple peel fibre pretreated with iso-propyl alcohol. The adsorption of Cu2+, Cd2+ and Pb2+ on the modified pineapple peel fibre depended on solution pH value, adsorption time and initial metal concentration. The maximum adsorption capacities of the modified fibre were observed at pH 5.4 for Cu2+ (27.68 +/- 0.83 mg g(-1) or 0.44 mmol g(-1)), at pH 7.5 for Cd2+ (34.18 +/- 1.02 mg g(-1) or 0.30 mmol g(-1)) and at pH 5.6 for Pb2+ (70.29 +/- 2.11 mg g(-1) or 0.34 mmol g(-1)) respectively. The adsorption followed the pseudo-second-order kinetics model and the experimental data coincided well with the Langmuir model.

  8. Rapid microwaves synthesis of CoSi{sub x}/CNTs as novel catalytic materials for hydrogenation of phthalic anhydride

    SciTech Connect

    Zhang, Liangliang; Chen, Xiao; Jin, Shaohua; Guan, Jingchao; Williams, Christopher T.; Peng, Zhijian; Liang, Changhai

    2014-09-15

    CoSi{sub x}/CNTs catalysts with different CoSi{sub x} phases (CoSi, CoSi{sub 2}) have been rapidly synthesized via a microwave-assisted route and applied for the liquid phase hydrogenation of phthalic anhydride. The synthesized catalysts were analyzed and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy-energy dispersive X-ray spectroscopy, thermogravimetric/derivative thermogravimetric analysis. The reaction progress of cobalt silicides and the ratio of Co:Si were monitored at different microwave irradiation times by XRD, giving insight into the formation mechanism. Compared to the Co/CNTs catalyst, all the prepared CoSi{sub x}/CNTs catalysts exhibited excellent activity and good selectivity to phthalide under mild reaction conditions (180–220 °C and 4.0 MPa H{sub 2}). This novel methodology can be applied to the synthesis of other transition metal silicides such as FeSi, Ni{sub 2}Si, and Cu{sub 4}Si. - Graphical abstract: CoSi{sub x}/CNTs catalysts with different CoSi{sub x} phases (CoSi{sub 2}, CoSi) have been rapidly synthesized via microwave-assisted route, which involves the vaporization of CoCl{sub 2} and subsequent reaction of CoCl{sub 2} with Si. - Highlights: • CoSi{sub x}/CNTs catalysts have been rapid synthesized via microwave-assisted route. • The phases of CoSi{sub x} were controlled by varying microwave time and Co:Si ratio. • FeSi, Ni{sub 2}Si and Cu{sub 4}Si were also synthesized via microwave-assisted route. • CoSi{sub x}/CNTs catalysts can be applied in hydrogenation of phthalic anhydride.

  9. Ionic Liquids as the MOFs/Polymer Interfacial Binder for Efficient Membrane Separation.

    PubMed

    Lin, Rijia; Ge, Lei; Diao, Hui; Rudolph, Victor; Zhu, Zhonghua

    2016-11-23

    Obtaining strong interfacial affinity between filler and polymer is critical to the preparation of mixed matrix membranes (MMMs) with high separation efficiency. However, it is still a challenge for micron-sized metal organic frameworks (MOFs) to achieve excellent compatibility and defect-free interface with polymer matrix. Thin layer of ionic liquid (IL) was immobilized on micron-sized HKUST-1 to eliminate the interfacial nonselective voids in MMMs with minimized free ionic liquid (IL) in polymer matrix, and then the obtained IL decorated HKUST-1 was incorporated into 4,4'-(hexafluoroisopropylidene)diphthalic anhydride-2,3,5,6-tetramethyl-1,3-phenyldiamine (6FDA-Durene) to fabricate MMMs. Acting as a filler/polymer interfacial binder, the favorable MOF/IL and IL/polymer interaction can facilitate the enhancement of MOF/polymer affinity. Compared to MMM with only HKUST-1 incorporation, MMM with IL decorated HKUST-1 succeeded in restricting the formation of nonselective interfacial voids, leading to an increment in CO2 selectivity. The IL decoration method can be an effective approach to eliminate interfacial voids in MMMs, extending the filler selection to a wide range of large-sized fillers.

  10. Development of repaglinide microspheres using novel acetylated starches of bitter and Chinese yams as polymers.

    PubMed

    Okunlola, Adenike; Adebayo, Amusa Sarafadeen; Adeyeye, Moji Christianah

    2017-01-01

    Tropical starches from Dioscorea dumetorum (bitter) and Dioscorea oppositifolia (Chinese) yams were acetylated with acetic anhydride in pyridine medium and utilized as polymers for the delivery of repaglinide in microsphere formulations in comparison to ethyl cellulose. Acetylated starches of bitter and Chinese yams with degrees of substitution of 2.56 and 2.70 respectively were obtained. Acetylation was confirmed by FTIR, (1)H NMR spectroscopy. A 3(2) factorial experimental design was performed using polymer type and drug-polymer ratio as independent variables. Particle size, swelling, entrapment and time for 50% drug release (t50) were dependent variables. Contour plots showed the relationship between the independent factors and the response variables. All variables except swelling increased with drug: polymer ratio. Entrapment efficiency was generally in the rank of Bitter yam>Ethyl cellulose>Chinese yam. Repaglinide microspheres had size 50±4.00 to 350±18.10μm, entrapment efficiency 75.30±3.03 to 93.10±2.75% and t50 3.20±0.42 to 7.20±0.55h. Bitter yam starch gave longer dissolution times than Chinese yam starch at all drug-polymer ratios. Drug release fitted Korsmeyer-Peppas and Hopfenberg models. Acetylated bitter and Chinese yam starches were found suitable as polymers to prolong release of repaglinide in microsphere formulations.

  11. Ultrathin, flexible, and transparent polymer multilayer composites for the protection of silver surfaces.

    PubMed

    Langecker, Jens; Ritter, Helene; Fichini, Audrey; Rupper, Patrick; Faller, Markus; Hanselmann, Barbara

    2012-02-01

    Silver coatings at the nanoscale became of high interest for the integration of electronic functionalities on all kinds of objects for daily use. In these thin coatings, corrosion is a big problem as it destroys these thin layers and leads to a loss of conductivity due to missing bulk material. For protection of thin silver coatings against H(2)S induced corrosion, we developed nanocoatings based on the covalent layer-by-layer technique. We prepared composites by subsequent deposition of polyamines like polyethylenimine (PEI) or polyallylamine (PAAm) and polyanhydrides like poly(maleic anhydride-alt-methyl vinyl ether) (Gantrez) or poly(styrene-co-maleic anhydride) (PSMA). For the tuning of the hydrophobicity, the layers were terminated by reaction with palmitoylic acid derivatives. Reflectivity measurements, contact angle measurements, and AFM measurements were made to investigate how the coatings affect the surface properties. All coatings show a lower reflectivity below 450 nm compared to pure silver, depending on the number of layers deposited. The addition of a palmitoylic derivative to the surface increases the hydrophobicity, but only in case of the Gantrez-PVAm-composite, this approach leads to real hydrophobicity, reaching contact angles above 90°. AFM measurements show a decrease of the roughness of the polymer coated surfaces compared to the pure metal surfaces. Corrosion tests in a H(2)S atmosphere show a good protective effect of the palmitoyl-terminated composites. Martindale abrasion tests on coated textiles reveal a good stability of the prepared polymer composites.

  12. Interpretations of Polymer-Polymer Miscibility.

    ERIC Educational Resources Information Center

    Olabisi, Olagoke

    1981-01-01

    Discusses various aspects of polymeric mixtures, mixtures of structurally different homopolymers, copolymers, terpolymers, and the like. Defines concepts of polymer-polymer miscibility from practical and theoretical viewpoints, and ways of predicting such miscibility. (JN)

  13. Tapered Bottlebrush Polymers: A New Polymer Architecture

    DTIC Science & Technology

    2015-07-30

    length of the backbone polymer . This type of covalent, cone- shaped polymer may have applications in supersoft elastomeric materials and as...rate of polymerization must be as high as possible for the synthesis of precise tapered bottlebrush polymers . An example of the kinetics data obtained... polymers with anchor group 1 allow for faster polymerization . MM Name k p (10 -3 L * mol -1 * s -1 ) t1/2 (s) krel 1S 3k 11 ± 2 68 ± 20

  14. PolyMorphine: an innovative biodegradable polymer drug for extended pain relief

    PubMed Central

    Rosario-Meléndez, Roselin; Harris, Carolyn L.; Delgado-Rivera, Roberto; Yu, Lei; Uhrich, Kathryn E.

    2012-01-01

    Morphine, a potent narcotic analgesic used for the treatment of acute and chronic pain, was chemically incorporated into a poly(anhydride-ester) backbone. The polymer termed “PolyMorphine”, was designed to degrade hydrolytically releasing morphine in a controlled manner to ultimately provide analgesia for an extended time period. PolyMorphine was synthesized via melt-condensation polymerization and its structure was characterized using proton and carbon nuclear magnetic resonance spectroscopies, and infrared spectroscopy. The weight-average molecular weight and the thermal properties were determined. The hydrolytic degradation pathway of the polymer was determined by in vitro studies, showing that free morphine is released. In vitro cytocompatibility studies demonstrated that PolyMorphine is non-cytotoxic towards fibroblasts. In vivo studies using mice showed that PolyMorphine provides analgesia for 3 days, 20 times the analgesic window of free morphine. The animals retained full responsiveness to morphine after being subjected to an acute morphine challenge. PMID:22877734

  15. From commodity polymers to functional polymers.

    PubMed

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-04-08

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications.

  16. From Commodity Polymers to Functional Polymers

    PubMed Central

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications. PMID:24710333

  17. Molecular depth profiling of multilayer polymer films using time-of-flight secondary ion mass spectrometry.

    PubMed

    Wagner, M S

    2005-02-01

    The low penetration depth and high sputter rates obtained using polyatomic primary ions have facilitated their use for the molecular depth profiling of some spin-cast polymer films by secondary ion mass spectrometry (SIMS). In this study, dual-beam time-of-flight (TOF) SIMS (sputter ion, 5 keV SF(5)(+); analysis ion, 10 keV Ar(+)) was used to depth profile spin-cast multilayers of poly(methyl methacrylate) (PMMA), poly(2-hydroxyethyl methacrylate) (PHEMA), and trifluoroacetic anhydride-derivatized poly(2-hydroxyethyl methacrylate) (TFAA-PHEMA) on silicon substrates. Characteristic positive and negative secondary ions were monitored as a function of depth using SF(5)(+) primary ion doses necessary to sputter through the polymer layer and uncover the silicon substrate (>5 x10(14) ions/cm(2)). The sputter rates of the polymers in the multilayers were typically less than for corresponding single-layer films, and the order of the polymers in the multilayer affected the sputter rates of the polymers. Multilayer samples with PHEMA as the outermost layer resulted in lowered sputter rates for the underlying polymer layer due to increased ion-induced damage accumulation rates in PHEMA. Additionally, the presence of a PMMA or PHEMA overlayer significantly decreased the sputter rate of TFAA-PHEMA underlayers due to ion-induced damage accumulation in the overlayer. Typical interface widths between adjacent polymer layers were 10-15 nm for bilayer films and increased with depth to approximately 35 nm for the trilayer films. The increase in interface width and observations using optical microscopy showed the formation of sputter-induced surface roughness during the depth profiles of the trilayer polymer films. This study shows that polyatomic primary ions can be used for the molecular depth profiling of some multilayer polymer films and presents new opportunities for the analysis of thin organic films using TOF-SIMS.

  18. Poly(2-vinylnaphthalene-alt-maleic acid)-graft polystyrene as a photoactive polymer micelle and stabilizer for polystyrene latexes

    SciTech Connect

    Cao, T.; Yin, W.; Webber, S.E. )

    1994-12-05

    Polymerization of maleic anhydride and 2-vinylnaphthalene produces alternating polymers. Imidization of the polymer with amino-terminated polystyrene yields different loadings of an alternating polymer with polystyrene combs''. Upton rigorous hydrolysis one obtains poly(2-vinylnaphthalene-alt-maleic acid)-graft-polystyrene (P2VNMA-PS), which is a fluorescent polymer with unusual solution properties and with significant surface activity. P2VNMA-PS forms a small micelle structure in solution or can be used as a surfactant for an emulsion polymerization of polystyrene (no cosurfactant is required), producing monodisperse latex particles which are stable for pH > 3.9. Centrifugation shows that >90% of the P2VNMA-PS is associated with the latex particles. Fluorescence quenching studies of the naphthalene excimer with Tl[sup +] indicate that approximately 84% and 77% of the naphthalene groups remain exposed to the aqueous phase when this polymer is micellized or incorporated onto a latex particle, respectively. These data imply that the P2VNMA-PS polymer is permanently associated with the exterior of the latex particle, as one would expect given the amphiphilic nature of this polymer.

  19. Shape memory polymers

    DOEpatents

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  20. 54 FR 38044: National Emission Standards for Hazardous Air Pollutants; Benzene Emissions From Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By- Product Recovery Plants

    EPA Pesticide Factsheets

    Final Rule on National Emission Standards for Hazardous Air Pollutants; Benzene Emissions From Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery Plants.

  1. Mixed anhydrides (phosphoric-carboxyl) are also formed in the esterification of 5'-amp with n-acetylaminoacyl imidazolides - Implications regarding the origin of protein synthesis

    NASA Technical Reports Server (NTRS)

    Wickramasinghe, Nalinie S. M. D.; Lacey, James C., Jr.

    1992-01-01

    Procedure for the formation of aminoacyl esters of monoribonucleotides with aminoacyl imidazolides were first reported by Gottikh et al. (1970) and summarized in 1970. This reaction has been widely used by us and numbers of other workers as a convenient means of preparing aminoacyl esters of nucleotides. We have previously reported that, under conditions of excess imidazolide, large amounts of bis 2', 3' esters are formed in addition to the monoesters. However, to our knowledge, no one has reported that in addition to the esters, relatively large amounts of the mixed anhydride, with the amino acid carboxyl attached to the phosphate, are also formed at short reaction times. We report here on the relative amounts of anhydride and esters formed in this reaction of racemic mixtures of eleven N-acetyl amino acid imidazolides with 5'-AMP and discuss the relevance of the findings to the origin of protein synthesis.

  2. Electronic Effects of Aluminum Complexes in the Copolymerization of Propylene Oxide with Tricyclic Anhydrides: Access to Well-Defined, Functionalizable Aliphatic Polyesters.

    PubMed

    Van Zee, Nathan J; Sanford, Maria J; Coates, Geoffrey W

    2016-03-02

    The synthesis of well-defined and functionalizable aliphatic polyesters remains a key challenge in the advancement of emerging drug delivery and self-assembly technologies. Herein, we investigate the factors that influence the rates of undesirable transesterification and epimerization side reactions at high conversion in the copolymerization of tricyclic anhydrides with excess propylene oxide using aluminum salen catalysts. The structure of the tricyclic anhydride, the molar ratio of the aluminum catalyst to the nucleophilic cocatalyst, and the Lewis acidity of the aluminum catalyst all influence the rates of these side reactions. Optimal catalytic activity and selectivity against these side reactions requires a careful balance of all these factors. Effective suppression of undesirable transesterification and epimerization was achieved even with sterically unhindered monomers using a fluorinated aluminum salph complex with a substoichiometric amount of a nucleophilic cocatalyst. This process can be used to synthesize well-defined block copolymers via a sequential addition strategy.

  3. One-pot synthesis of 2-amino-4(3H)-quinazolinones via ring-opening of isatoic anhydride and palladium-catalyzed oxidative isocyanide-insertion.

    PubMed

    Ji, Fei; Lv, Mei-Fang; Yi, Wen-Bin; Cai, Chun

    2014-08-14

    An efficient and practical two-step process has been developed for the synthesis of 2-amino-4(3H)-quinazolinones via ring-opening of isatoic anhydride and palladium-catalyzed oxidative isocyanide-insertion in one pot. This regioselective procedure could construct a wide range of 2-amino-4(3H)-quinazolinones in moderate to excellent yields. Furthermore, the methodology also had distinct advantages of easily accessible starting materials and operational simplicity.

  4. [Influence of low concentration of sulphuric anhydride on metabolic status of peripheral blood lymphocytes in guinea pigs sensibilised with a biological allergen].

    PubMed

    Dolgushin, M V; Sosedova, L M

    2005-01-01

    The influence of sulphuric anhydride (2-4 mg/m3) on the metabolic status of peripheral blood lymphocytes of sensibilised guinea pigs with different sequence of biological (allergenic) and chemical exposure has been studied. The metabolic state was evaluated by histochemical assay of succinate and lactate dehydrogenases and acid phosphatase. The changes in activities of dehydrogenases were found to indicate a definite relationship with specific responses of combined effects of different factors.

  5. Effect of hydrostatic pressure, temperature, and solvent on the rate of the Diels-Alder reaction between 9,10-anthracenedimethanol and maleic anhydride

    NASA Astrophysics Data System (ADS)

    Kiselev, V. D.; Kornilov, D. A.; Anikin, O. V.; Latypova, L. I.; Konovalov, A. I.

    2017-03-01

    The rate of the reaction between 9,10-anthracenedimethanol and maleic anhydride in 1,4-dioxane, acetonitrile, trichloromethane, and toluene is studied at 25, 35, 45°C in the pressure range of 1-1772 bar. The rate constants, enthalpies, entropies and activation volumes are determined. It is shown that the rate of reaction with 9,10-anthracenedimethanol is approximately one order of magnitude higher than with 9-anthracenemethanol.

  6. In Vivo Evaluation of Nerve Guidance Conduits Comprised of a Salicylic Acid-based Poly(anhydride-ester) Blend

    NASA Astrophysics Data System (ADS)

    Lee, Yong Soo

    Unlike the central nervous system, peripheral nervous system can regenerate from injury. However, without surgical intervention, the results are often poor. Autologous nerve grafting is the golden standard for repairing peripheral nerve injury; but limited donor availability and donor site morbidity led researchers to seek alternative methods. Among the many alternative treatment options, synthetic nerve guidance conduits (NGCs) have been most actively developed. The goal of NGCs is to serve as a physical scaffold that aids the axonal regeneration process while preventing scar tissue formation that interferes with regeneration. Biocompatible and biodegradable NGCs would provide additional benefits: minimize foreign body reaction and avoid secondary surgeries to remove NGCs. We developed a unique NGC that incorporated the characteristics described above and can release an anti-inflammatory drug, salicylic acid. In this work, in vivo assays were performed to evaluate NGCs fabricated from a poly(anhydride-ester) blend. To further assist in the regeneration process, bovine native collagen type I hydrogel were inserted into the NGCs lumen which was then implanted in femoral nerve of mice for up to 16 weeks. These studies demonstrated in vivo biodegradability, biocompatibility, and axonal regeneration following an injury to the peripheral nerve. These studies provide greater insights into the importance of designing NGCs and how they aid in regeneration and functional recovery of subjects.

  7. Intranasal Administration of Maleic Anhydride-Modified Human Serum Albumin for Pre-Exposure Prophylaxis of Respiratory Syncytial Virus Infection

    PubMed Central

    Sun, Zhiwu; Wang, Qian; Jia, Ran; Xia, Shuai; Li, Yuan; Liu, Qi; Xu, Wei; Xu, Jin; Du, Lanying; Lu, Lu; Jiang, Shibo

    2015-01-01

    Respiratory syncytial virus (RSV) is the leading cause of pediatric viral respiratory tract infections. Neither vaccine nor effective antiviral therapy is available to prevent and treat RSV infection. Palivizumab, a humanized monoclonal antibody, is the only product approved to prevent serious RSV infection, but its high cost is prohibitive in low-income countries. Here, we aimed to identify an effective, safe, and affordable antiviral agent for pre-exposure prophylaxis (PrEP) of RSV infection in children at high risk. We found that maleic anhydride (ML)-modified human serum albumin (HSA), designated ML-HSA, exhibited potent antiviral activity against RSV and that the percentages of the modified lysines and arginies in ML- are correlated with such anti-RSV activity. ML-HSA inhibited RSV entry and replication by interacting with viral G protein and blocking RSV attachment to the target cells, while ML-HAS neither bound to F protein, nor inhibited F protein-mediated membrane fusion. Intranasal administration of ML-HSA before RSV infection resulted in significant decrease of the viral titers in the lungs of mice. ML-HSA shows promise for further development into an effective, safe, affordable, and easy-to-use intranasal regimen for pre-exposure prophylaxis of RSV infection in children at high risk in both low- and high-income countries. PMID:25690799

  8. Preparation, characterization and luminescent properties of dense nano-silica hybrids loaded with 1,8-naphthalic anhydride.

    PubMed

    Wang, Jinpeng; Sun, Jihong; Li, Yuzhen; Wang, Feng

    2014-03-01

    Novel luminescent dense nano-silica hybrid materials (DNSS) modified with different amounts of (3-aminopropyl)triethoxysilane (APTES) and 1,8-naphthalic anhydride (NA) were successfully synthesized via two steps combined with post-grafting methods. Powder X-ray diffraction (XRD), N2-sorption analysis, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), photoluminescence (PL) spectroscopy and elemental analysis, as well as time-resolved decays were employed to characterize the resultant hybrid materials. The results revealed that luminescent organic molecules had been successfully loaded onto the amine-modified surface of nano-silica spheres. In addition, their fluorescence intensity and characteristic peak of emission spectra changed with increasing amount of APTES and NA additive. In particular, the characteristic peak showed a red shift from 390 to 450 nm, however, this was inconsistent with results calculated on the basis of the elemental analysis data, most probably because of the dispersion behaviors of NA molecules from the aggregating to the monolayer state. These observations demonstrated the existence of a quantum confinement effectiveness of NA-DNSS samples, and therefore a possible mechanism was put forward.

  9. Thermal decomposition behaviors and kinetic properties of 1,8-naphthalic anhydride loaded dense nano-silica hybrids

    NASA Astrophysics Data System (ADS)

    Wang, Jinpeng; Sun, Jihong; Wang, Feng; Ren, Bo

    2013-06-01

    A certain amount of (3-aminopropyl)triethoxysilane (APTES) and various capacity of 1,8-naphthalic anhydride (NA) were employed to modify and then graft onto the surface of the dense nano-silica spheres (DNSS) via a post-grafting method, and thereby, a novel luminescent density nano-silica hybrid materials have been successfully synthesized. Meanwhile, the structures and properties of obtained hybrid DNSS were characterized by XRD, TEM, N2 sorption, FT-IR, and TG analysis. Furthermore, the thermal stability of before and after modification were demonstrated by using both Kissinger methods and Ozawa-Flynn-Wall methods. Particularly, the thermal decomposition behaviors of amino-modified groups and NA-grafted organic molecules were emphasized based on the TG and DTG analysis and then the related mechanism was put forward according to Coats and Redfern methods. Finally, as a comparison, the obtained results and the proposed decomposition mechanism of hybrid DNSS with non-pores were discussed with that of mesopores silicas in details.

  10. Study of yellow luminescence of binary terbium complexes based on 3,3',4,4'-biphthalic anhydride.

    PubMed

    Lin, Meijuan; Wang, Xiaoping; Tang, Qiang; An, Qi; Zeng, Huijuan; Ling, Qidan

    2014-01-20

    Three novel binary Tb(III) complexes (TbL2, TbL, and Tb2L; L=3,3',4,4'-biphenyl tetracarboxylic ligand) were synthesized by changing the molar ratio of Tb(III) to 3,3',4,4'-biphthalic anhydride (BPDA) (1∶2, 1∶1, and 2∶1, respectively). IR spectra indicate that there are two coordination modes of the carboxylate ligands with Tb3+ ions in the complexes. Most of them are in bridging mode; the others are in chelating mode. These complexes all have good thermal stability. The photophysical properties of these complexes are studied in detail using UV absorption spectra, fluorescence spectra, and transient fluorescence spectra. The results indicate that the photoluminescence properties of the complexes depend strongly on the molar ratio of Tb(III) to BPDA. When the molar ratio of Tb(III) to BPDA is 1∶1, complex TbL exhibits the strongest yellow light emission among the three Tb(III) complexes. However, complex Tb2L exhibits a weaker yellowish-green light emission when the molar ratio of Tb(III) to BPDA is 2∶1. The phenomenon of the yellow emission from terbium complexes is rarely reported.

  11. Olefin-maleic-anhydride copolymer based additives: a novel approach for compatibilizing blends of waste polyethylene and crumb rubber.

    PubMed

    Tóth, Balázs; Varga, Csilla; Bartha, László

    2015-04-01

    In our work processing conditions and mechanical properties of waste polyethylene (PE)/crumb rubber (CR) blends have been improved by new types of compatibilizing additives synthesized from experimental olefin-maleic-anhydride copolymers at our laboratory. Compatibilizing additives have been introduced into the PE/CR blends in 0.2 wt% while CR concentration has been varied between 10 and 50 wt%. For comparison of the effects commercially available MA-g-PO type compatibilizing additives have also been applied. Tensile and Charpy impact tests of the compression moulded samples have been carried out. Several experimental additives have enhanced properties of the PE/CR blends either from the point of view of tensile or Charpy impact strength while commercial additives have had improving effects only on one of the abovementioned mechanical properties but not for both of them simultaneously. Since good mechanical properties could be achieved by our experimental compatibilizers good adhesion in the waste PE/CR samples have been considered and was proven by SEM graphs either.

  12. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation.

    PubMed

    Godoy-Gallardo, Maria; Guillem-Marti, Jordi; Sevilla, Pablo; Manero, José M; Gil, Francisco J; Rodriguez, Daniel

    2016-02-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria-cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties.

  13. Estimating regio and stereoselectivity in [4+2] cycloadditions of vinyl-substituted cyclic dienes with maleic anhydride.

    PubMed

    Gayatri, Gaddamanugu; Sastry, G Narahari

    2009-10-29

    Density functional theory calculations are performed to examine the regio and stereoselective preferences in [4+2] cycloaddition reactions of vinyl cyclopentadiene (1 and 2) and vinyl heterocyclic (1-N, 1-O, 1-S, 2-N, 2-O and 2-S) systems with maleic anhydride. Stepwise and concerted pathways of model systems 1 and 2 as dienes with ethylene as dienophile reveal that the reactions proceed through asynchronous and concerted pathway. 3-Vinyl systems (2) are predicted to be more reactive compared to 2-vinyl systems (1). The regio and stereoselective preferences are evaluated based on activation energies, reaction energies, density functional based descriptors and atoms in molecules analysis. In all cases, extra-annular cycloadducts are more feasible compared to intra-annular cycloadducts. Stereoselectivity depends on the favorable secondary orbital interactions. Solvents such as water, tetrahydrofuran, acetone, and dimethyl sulphoxide are employed to understand the effects of solvents on the cycloadduct formation. The computational results thus obtained are compared with the earlier experimental observations that are available.

  14. Slow digestion property of octenyl succinic anhydride modified waxy maize starch in the presence of tea polyphenols.

    PubMed

    Peng, Shanli; Xue, Lei; Leng, Xue; Yang, Ruobing; Zhang, Genyi; Hamaker, Bruce R

    2015-03-18

    The in vivo slow digestion property of octenyl succinic anhydride modified waxy corn starch (OSA-starch) in the presence of tea polyphenols (TPLs) was studied. Using a mouse model, the experimental results showed an extended and moderate postprandial glycemic response with a delayed and significantly decreased blood glucose peak of OSA-starch after cocooking with TPLs (5% starch weight base). Further studies revealed an increased hydrodynamic radius of OSA-starch molecules indicating an interaction between OSA-starch and TPLs. Additionally, decreased gelatinization temperature and enthalpy and reduced viscosity and emulsifiability of OSA-starch support their possible complexation to form a spherical OSA-starch-TPLs (OSAT) complex. The moderate and extended postprandial glycemic response is likely caused by decreased activity of mucosal α-glucosidase, which is noncompetitively inhibited by tea catechins released from the complex during digestion. Meanwhile, a significant decrease of malondialdehyde (MDA) and increased DPPH free radical scavenging activity in small intestine tissue demonstrated the antioxidative functional property of the OSAT complex. Thus, the complex of OSAT, acting as a functional carbohydrate material, not only leads to a flattened and prolonged glycemic response but also reduces the oxidative stress, which might be beneficial to health.

  15. Inhaled multiwalled carbon nanotubes modulate the immune response of trimellitic anhydride-induced chemical respiratory allergy in brown Norway rats.

    PubMed

    Staal, Yvonne C M; van Triel, Jos J; Maarschalkerweerd, Thérèse V P; Arts, Josje H E; Duistermaat, Evert; Muijser, Hans; van de Sandt, Johannes J M; Kuper, C Frieke

    2014-10-01

    The interaction between exposure to nanomaterials and existing inflammatory conditions has not been fully established. Multiwalled carbon nanotubes (MWCNT; Nanocyl NC 7000 CAS no. 7782-42-5; count median diameter in atmosphere 61 ± 5 nm) were tested by inhalation in high Immunoglobulin E (IgE)-responding Brown Norway (BN) rats with trimellitic anhydride (TMA)-induced respiratory allergy. The rats were exposed 2 days/week over a 3.5-week period to a low (11 mg/m(3)) or a high (22 mg/m(3)) concentration of MWCNT. Nonallergic animals exposed to MWCNT and unexposed allergic and nonallergic rats served as controls. At the end of the exposure period, the allergic animals were rechallenged with TMA. Histopathological examination of the respiratory tract showed agglomerated/aggregated MWCNT in the lungs and in the lung-draining lymph nodes. Frustrated phagocytosis was observed as incomplete uptake of MWCNT by the alveolar macrophages and clustering of cells around MWCNT. Large MWCNT agglomerates/aggregates were found in granulomas in the allergic rats, suggesting decreased macrophage clearance in allergic rats. In allergic rats, MWCNT exposure decreased serum IgE levels and the number of lymphocytes in bronchoalveolar lavage. In conclusion, MWCNT did not aggravate the acute allergic reaction but modulated the allergy-associated immune response.

  16. Modification of bovine heart succinate dehydrogenase with ethoxyformic anhydride and rose bengal: evidence for essential histidyl residues protectable by substrates.

    PubMed

    Hederstedt, L; Hatefi, Y

    1986-06-01

    Purified and membrane-bound succinate dehydrogenase (SDH) from bovine heart mitochondria was inhibited by the histidine-modifying reagents ethoxyformic anhydride (EFA) and Rose Bengal in the presence of light. Succinate and competitive inhibitors protected against inhibition, and decreased the number of histidyl residues modified by EFA. The essential residue modified by EFA was not the essential thiol of SDH, but modification of the essential thiol abolished the protective effect of malonate against inhibition of SDH by EFA. The EFA inhibition was reversed by hydroxylamine nearly completely when the inhibition was less than or equal to 35%, and only partially when the inhibition was more extensive. The uv spectrum of EFA-modified SDH before and after hydroxylamine treatment suggested that extensive inhibition of SDH with EFA may result in ethoxyformylation at both imidazole nitrogens of histidyl residues. Such a modification is not reversed by hydroxylamine. Succinate dehydrogenases and fumarate reductases from several different sources have similar compositions, and the two enzymes from Escherichia coli have considerable homology in the amino acid composition of their respective flavoprotein and iron-sulfur protein subunits. In the former, there is a short stretch containing conserved histidine, cysteine, and arginine residues. These residues, if also conserved in the bovine enzyme, may be the essential active site residues suggested by this work (histidine) and previously (cysteine, arginine).

  17. Microencapsulation of white champaca (Michelia alba D.C.) extract using octenyl succinic anhydride (OSA) starch for controlled release aroma.

    PubMed

    Samakradhamrongthai, Rajnibhas; Thakeow, Prodpran; Kopermsub, Phikunthong; Utama-Ang, Niramon

    2016-12-01

    The objective of the study was to optimise the encapsulation of Michelia alba D.C. (MAD) extract using octenyl succinic anhydride (OSA) starch. The MAD extract (5-10 g/100 g of dry starch) and the OSA starch (25-100 g/100 ml of water) was used in microcapsule preparation and analysed for the physicochemical and encapsulation properties. The optimised formula using the MAD extract and the OSA starch were 15.00 g/100 g of dry starch and 96.32 g/100 g water, which provided the highest in yield recovery (40.65% ± 0.99) and encapsulation efficiency (68.91% ± 1.50), with the lowest moisture content (3.19% ± 0.06) and water activity (0.236 ± 0.004). The aroma release from the optimum encapsulated powder in simulated artificial saliva fluid (SSF) suggested that linalool retention in microcapsules was higher than verbenone and 2-methyl butanoic acid. This study shows that the optimised formulation of MAD encapsulated flavour powder was found to be effective for controlling the aroma release.

  18. Experimental and theoretical study on the reaction of N3-phenyl-(pyridin-2-yl)carbohydrazonamide with itaconic anhydride

    NASA Astrophysics Data System (ADS)

    Modzelewska-Banachiewicz, Bożena; Paprocka, Renata; Mazur, Liliana; Saczewski, Jarosław; Kutkowska, Jolanta; Stępień, Dorota K.; Cyrański, Michał

    2012-08-01

    Two new 1,2,4-triazole-containing alkenoic acid derivatives were obtained from the reaction of N-phenyl-(pyridin-2-yl)carbohydrazonamide with itaconic anhydride, depending on the reaction conditions. The structures of 2-((4-phenyl-5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl)methyl)acrylic acid or (E)-2-methyl-3(4-phenyl-5-(pyridine-2-yl)-4H-1,2,4-triazol-3-yl)acrylic acid were confirmed by means of 1D and 2D NMR spectroscopic data as well as by single-crystal X-ray diffraction analysis. The experiential 1H and 13C chemical shifts were compared with those calculated with B3LYP, EDF1, and EDF2 density functional theories. The theoretical study of the observed terminal-to-internal alkene isomerization was performed with density functional (DFT) B3LYP/6-31+G∗ method using SM8 water and DMF solvation models. Antimicrobial activities of the newly prepared alkenoic acid derivatives were verified experimentally by a broth microdilution method.

  19. Interface-mediated inactivation of pancreatic lipase by a water-reactive compound: 2-sulfobenzoic cyclic anhydride.

    PubMed

    Moulin, A; Fourneron, J D; Piéroni, G; Verger, R

    1989-07-25

    2-Sulfobenzoic cyclic anhydride (SBA) rapidly and selectively inactivates porcine pancreatic lipase (PPL) only when added during the hydrolysis of an emulsified ester such as tributyrin or dodecyl acetate. The present data suggest that the inactivation of PPL occurs preferentially at the oil/water interface and not in the aqueous phase, since colipase and bile salt were found to adversely affect the inhibition process. Moreover, it is shown that at a molar ratio of SBA to pure PPL of 1, 40% of the lipase activity was already irreversibly lost. Complete inactivation was observed at SBA to pure PPL molar ratios of 120. A 60% inactivation occurred when 0.5 mol of 3H-labeled SBA was attached per mole of PPL. The SBA-inactivated PPL competes for binding to the dodecyl acetate/water interface as efficiently as the native enzyme. Larger SBA concentrations are required when crude lipase preparations are used as well as with pure PPL in the presence of bile salts and colipase. Lipases were found to have variable sensitivities to SBA inactivation, depending on their origin. In the presence of bile salts and tributyrin at pH 6.0, human gastric lipase activity was not affected by the presence of a 10(6) molar excess of SBA.

  20. Polymer Functionalized Nanoparticles in Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Jayaraman, Arthi

    2013-03-01

    Significant interest has grown around the ability to control spatial arrangement of nanoparticles in a polymer nanocomposite to engineer materials with target properties. Past work has shown that one could achieve controlled assembly of nanoparticles in the polymer matrix by functionalizing nanoparticle surfaces with homopolymers. This talk will focus on our recent work using Polymer Reference Interaction Site Model (PRISM) theory and Monte Carlo simulations and GPU-based molecular dynamics simulations to specifically understand how heterogeneity in the polymer functionalization in the form of a) copolymers with varying monomer chemistry and monomer sequence, and b) polydispersity in homopolymer grafts can tune effective interactions between functionalized nanoparticles, and the assembly of functionalized nanoparticles.

  1. Lipid-absorbing Polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Wallace, C. J.

    1973-01-01

    The removal of bile acids and cholesterol by polymeric absorption is discussed in terms of micelle-polymer interaction. The results obtained with a polymer composed of 75 parts PEO and 25 parts PB plus curing ingredients show an absorption of 305 to 309%, based on original polymer weight. Particle size effects on absorption rate are analyzed. It is concluded that crosslinked polyethylene oxide polymers will absorb water, crosslinked polybutadiene polymers will absorb lipids; neither polymer will absorb appreciable amounts of lipids from micellar solutions of lipids in water.

  2. A versatile strategy for grafting polymers to wood cell walls.

    PubMed

    Keplinger, T; Cabane, E; Chanana, M; Hass, P; Merk, V; Gierlinger, N; Burgert, I

    2015-01-01

    The hierarchical structure of wood is composed of a cellulose skeleton of high structural order at various length scales. At the nanoscale and microscale the specific structural features of the cells and cell walls result in a lightweight structure with an anisotropic material profile of excellent mechanical performance. By being able to specifically functionalize wood at the level of cell and cell walls one can insert new properties and inevitably upscale them along the intrinsic hierarchical structure, to a level of large-scale engineering materials applications. For this purpose, however, precise control of the spatial distribution of the modifying substances in the complex wood structure is needed. Here we demonstrate a method to insert methacryl groups into wood cell walls using two different chemistry routes. By using these methacryl groups as the anchor points for grafting, various polymers can be inserted into the wood structure. Strikingly, depending on the methacryl precursor, the spatial distribution of the polymer differs strongly. As a proof of concept we grafted polystyrene as a model compound in the second modification step. In the case of methacryloyl chloride the polymer was located mainly at the interface between the cell lumina and the cell wall covering the inner surface of the cells and being traceable up to 2-3 μm in the cell wall, whereas in the case of methacrylic anhydride the polymer was located inside the whole cell wall. Scanning electron microscopy, Fourier transform infrared spectroscopy and especially Raman spectroscopy were used for an in-depth analysis of the modified wood at the cell wall level.

  3. Playing with Polymers.

    ERIC Educational Resources Information Center

    Chemecology, 1997

    1997-01-01

    Presents an activity that enables students to gain a better understanding of the importance of polymers. Students perform an experiment in which polymer chains of polyvinyl acetate form crosslinks. Includes background information and discussion questions. (DDR)

  4. Polymer composites containing nanotubes

    NASA Technical Reports Server (NTRS)

    Bley, Richard A. (Inventor)

    2008-01-01

    The present invention relates to polymer composite materials containing carbon nanotubes, particularly to those containing singled-walled nanotubes. The invention provides a polymer composite comprising one or more base polymers, one or more functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers and carbon nanotubes. The invention also relates to functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers, particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having side chain functionalization, and more particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having olefin side chains and alkyl epoxy side chains. The invention further relates to methods of making polymer composites comprising carbon nanotubes.

  5. Polymer Fluid Dynamics.

    ERIC Educational Resources Information Center

    Bird, R. Byron

    1980-01-01

    Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)

  6. Introduction to Polymer Chemistry.

    ERIC Educational Resources Information Center

    Harris, Frank W.

    1981-01-01

    Reviews the physical and chemical properties of polymers and the two major methods of polymer synthesis: addition (chain, chain-growth, or chain-reaction), and condensation (step-growth or step-reaction) polymerization. (JN)

  7. Mechanical Properties of Polymers.

    ERIC Educational Resources Information Center

    Aklonis, J. J.

    1981-01-01

    Mechanical properties (stress-strain relationships) of polymers are reviewed, taking into account both time and temperature factors. Topics include modulus-temperature behavior of polymers, time dependence, time-temperature correspondence, and mechanical models. (JN)

  8. ALUMINUM-CONTAINING POLYMERS

    DTIC Science & Technology

    ALUMINUM COMPOUNDS, *ORGANOMETALLIC COMPOUNDS, *POLYMERIZATION, *POLYMERS, ACRYLIC RESINS, ALKYL RADICALS, CARBOXYLIC ACIDS, COPOLYMERIZATION, LIGHT TRANSMISSION, STABILITY, STYRENES, TRANSPARENT PANELS.

  9. Dendritic polyurea polymers.

    PubMed

    Tuerp, David; Bruchmann, Bernd

    2015-01-01

    Dendritic polymers, subsuming dendrimers as well as hyperbranched or highly branched polymers are well established in the field of polymer chemistry. This review article focuses on urea based dendritic polymers and summarizes their synthetic routes through both isocyanate and isocyanate-free processes. Furthermore, this article highlights applications where dendritic polyureas show their specific chemical and physical potential. For these purposes scientific publications as well as patent literature are investigated to generate a comprehensive overview on this topic.

  10. Stretching and imaging of single DNA chains on a hydrophobic polymer surface made of amphiphilic alternating comb-copolymer.

    PubMed

    Liu, Rongrong; Wong, Sheau Tyug; Lau, Peggy Pei Zhi; Tomczak, Nikodem

    2014-02-26

    Functionalization of amine derivatized glass slides with a poly(maleic anhydride)-based comb-copolymer to facilitate stretching, aligning, and imaging of individual dsDNA chains is presented. The polymer-coated surface is hydrophobic due to the presence of the long alkyl side chains along the polymer backbone. The surface is also characterized by low roughness and a globular morphology. Stretched and aligned bacteriophage λ-DNA chains were obtained using a robust method based on stretching by a receding water meniscus at pH 7.8 without the need for small droplet volumes or precoating the surface with additional layers of (bio)molecules. Although the dye to DNA base pairs ratio did not influence substantially the stretching length distributions, a clear peak at stretching lengths close to the contour length of the dsDNA is visible at larger staining ratios.

  11. Engineered Protein Polymers

    DTIC Science & Technology

    2010-05-31

    of each pure polymer, we plan to combine the various polymer solutions in different ratios to tune the composition and physico-chemical properties...protein materials as vehicles for storage and delivery of small molecules. Each protein polymer under concentrations for particle formation ( vida

  12. Synthetic hydrophilic polymers

    NASA Astrophysics Data System (ADS)

    Rajasekharan Pillai, V. N.; Mutter, Manfred

    1981-11-01

    Synthetic hydrophilic polymers find promising applications in pharmacology, biotechnology and chemistry. The biocompatibility, biodegradability and pharmacological activity of these polymers depend much on their hydrophilic nature. This article summarizes the recent developments in the utilization of the different classes of these hydrophilic polymers as pharmacologically active agents, for enzyme modification and as catalysts and supports for chemical reactions.

  13. Dynamic covalent polymers.

    PubMed

    García, Fátima; Smulders, Maarten M J

    2016-11-15

    This Highlight presents an overview of the rapidly growing field of dynamic covalent polymers. This class of polymers combines intrinsic reversibility with the robustness of covalent bonds, thus enabling formation of mechanically stable, polymer-based materials that are responsive to external stimuli. It will be discussed how the inherent dynamic nature of the dynamic covalent bonds on the molecular level can be translated to the macroscopic level of the polymer, giving access to a range of applications, such as stimuli-responsive or self-healing materials. A primary distinction will be made based on the type of dynamic covalent bond employed, while a secondary distinction will be based on the consideration whether the dynamic covalent bond is used in the main chain of the polymer or whether it is used to allow side chain modification of the polymer. Emphasis will be on the chemistry of the dynamic covalent bonds present in the polymer, in particular in relation to how the specific (dynamic) features of the bond impart functionality to the polymer material, and to the conditions under which this dynamic behavior is manifested. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3551-3577.

  14. New polymer systems: Chain extension by dianhydrides

    NASA Technical Reports Server (NTRS)

    Rhein, R. A.; Ingham, J. D.

    1972-01-01

    The results are presented for a systematic investigation on the use of anhydrides to prepare stable elastomeric materials for space use, under mild reaction conditions. The three anhydrides investigated were found to provide effective chain extension of hydroxy-terminated poly(alkylene oxides) and poly(butadienes). These were tetrahydrofuran tetracarboxylic dianhydride, pyromellitic dianhydride, and benzophenone tetracarboxylic diahydride. The most effective catalyst investigated was ferric acetylacetonate, which resulted in chain extension at 333 K (60 C). One feature of these anhydride reactants is that they are difunctional as anhydrides, but tetrafunctional if conditions are selected that lead to reaction of all carboxyl groups. Therefore, chain extension can be effected and then followed by crosslinking via the residual carboxyl groups.

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  16. Sustained Release of Antibacterial Lipopeptides from Biodegradable Polymers against Oral Pathogens

    PubMed Central

    Eckhard, Lea H.; Houri-Haddad, Yael; Sol, Asaf; Zeharia, Rotem; Shai, Yechiel; Beyth, Shaul; Domb, Abraham J.

    2016-01-01

    The development of antibacterial drugs to overcome various pathogenic species, which inhabit the oral cavity, faces several challenges, such as salivary flow and enzymatic activity that restrict dosage retention. Owing to their amphipathic nature, antimicrobial peptides (AMPs) serve as the first line of defense of the innate immune system. The ability to synthesize different types of AMPs enables exploitation of their advantages as alternatives to antibiotics. Sustained release of AMPs incorporated in biodegradable polymers can be advantageous in maintaining high levels of the peptides. In this study, four potent ultra-short lipopeptides, conjugated to an aliphatic acid chain (16C) were incorporated in two different biodegradable polymers: poly (lactic acid co castor oil) (PLACO) and ricinoleic acid-based poly (ester-anhydride) (P(SA-RA)) for sustained release. The lipopeptide and polymer formulations were tested for antibacterial activity during one week, by turbidometric measurements of bacterial outgrowth, anti-biofilm activity by live/dead staining, biocompatibility by hemolysis and XTT colorimetric assays, mode of action by fluorescence-activated cell sorting (FACS) and release profile by a fluorometric assay. The results show that an antibacterial and anti-biofilm effect, as well as membrane disruption, can be achieved by the use of a formulation of lipopeptide incorporated in biodegradable polymer. PMID:27606830

  17. Evaluation of methods for measuring relative permeability of anhydride from the Salado Formation: Sensitivity analysis and data reduction

    SciTech Connect

    Christiansen, R.L.; Kalbus, J.S.; Howarth, S.M.

    1997-05-01

    This report documents, demonstrates, evaluates, and provides theoretical justification for methods used to convert experimental data into relative permeability relationships. The report facilities accurate determination of relative permeabilities of anhydride rock samples from the Salado Formation at the Waste Isolation Pilot Plant (WIPP). Relative permeability characteristic curves are necessary for WIPP Performance Assessment (PA) predictions of the potential for flow of waste-generated gas from the repository and brine flow into repository. This report follows Christiansen and Howarth (1995), a comprehensive literature review of methods for measuring relative permeability. It focuses on unsteady-state experiments and describes five methods for obtaining relative permeability relationships from unsteady-state experiments. Unsteady-state experimental methods were recommended for relative permeability measurements of low-permeability anhydrite rock samples form the Salado Formation because these tests produce accurate relative permeability information and take significantly less time to complete than steady-state tests. Five methods for obtaining relative permeability relationships from unsteady-state experiments are described: the Welge method, the Johnson-Bossler-Naumann method, the Jones-Roszelle method, the Ramakrishnan-Cappiello method, and the Hagoort method. A summary, an example of the calculations, and a theoretical justification are provided for each of the five methods. Displacements in porous media are numerically simulated for the calculation examples. The simulated product data were processed using the methods, and the relative permeabilities obtained were compared with those input to the numerical model. A variety of operating conditions were simulated to show sensitivity of production behavior to rock-fluid properties.

  18. Alveolar macrophages have a dual role in a rat model for trimellitic anhydride-induced occupational asthma

    SciTech Connect

    Valstar, Dingena L.; Schijf, Marcel A.; Nijkamp, Frans P.; Storm, Gert; Arts, Josje H.E.; Kuper, C. Frieke; Bloksma, Nanne; Henricks, Paul A.J. . E-mail: p.a.j.henricks@pharm.uu.nl

    2006-02-15

    Occupational exposure to low molecular weight chemicals, like trimellitic anhydride (TMA), can result in occupational asthma. Alveolar macrophages (AMs) are among the first cells to encounter inhaled compounds. These cells can produce many different mediators that have a putative role in asthma. In this study, we examined the role of AMs in lung function and airway inflammation of rats exposed to TMA. Female Brown Norway rats were sensitized by dermal application of TMA or received vehicle alone on days 0 and 7. One day before challenge, rats received intratracheally either empty or clodronate-containing liposomes to deplete the lungs of AMs. On day 21, all rats were challenged by inhalation of TMA in air. Lung function parameters were measured before, during, within 1 h after, and 24 h after challenge. IgE levels and parameters of inflammation and tissue damage were assessed 24 h after challenge. Sensitization with TMA led to decreased lung function parameters during and within 1 h after challenge as compared to non-sensitized rats. AM depletion alleviated the TMA-induced drop in lung function parameters and induced a faster recovery compared to sham-depleted TMA-sensitized rats. It also decreased the levels of serum IgE 24 h after challenge, but did not affect the sensitization-dependent increase in lung lavage fluid IL-6 and tissue TNF-{alpha} levels. In contrast, AM depletion augmented the TMA-induced tissue damage and inflammation 24 h after challenge. AMs seem to have a dual role in this model for TMA-induced occupational asthma since they potentiate the immediate TMA-induced decrease in lung function but tended to dampen the TMA-induced inflammatory reaction 24 h later.

  19. Chemical modification with phthalic anhydride and chitosan: Viable options for the stabilization of raw starch digesting amylase from Aspergillus carbonarius.

    PubMed

    Nwagu, Tochukwu Nwamaka; Okolo, Bartholomew; Aoyagi, Hideki; Yoshida, Shigeki

    2017-06-01

    The raw starch digesting type of amylase (RSDA) presents greater opportunities for process efficiency at cheaper cost and shorter time compared to regular amylases. Chemical modification is a simple and rapid method toward their stabilization for a wider application. RSDA from Aspergillus carbonarius was modified with either phthalic anhydride (PA) or chitosan. Activity retention was 87.3% for PA-modified and 80.9% for chitosan-modified RSDA. Optimum pH shifted from 5 to 7 after PA-modification. Optimum temperature changed from 30°C (native) to 30-40°C and 60°C for PA-modified and chitosan-modified, respectively. Activation energy (kJmol(-1)) for hydrolysis was 13.5, 12.7, and 10.2 while the activation energy for thermal denaturation was 32.8, 80.3, 81.9 for free, PA-modified and chitosan-modified, respectively. The specificity constants (Vmax/Km) were 73.2 for PA-modified, 63.1 for chitosan-modified and 77.1 for native RSDA. The half-life (h) of the RSDA at 80°C was increased from 6.1 to 25.7 for the PA-modified and 138.6 for the chitosan derivative. Modification also led to increase in D value, activation enthalpy and Gibbs free energy of enzyme deactivation. Fluorescence spectra showed that center of spectral mass decreased for the PA-modified RSDA but increased for chitosan modified RSDA.

  20. Fire-safe polymers and polymer composites

    NASA Astrophysics Data System (ADS)

    Zhang, Huiqing

    The intrinsic relationships between polymer structure, composition and fire behavior have been explored to develop new fire-safe polymeric materials. Different experimental techniques, especially three milligram-scale methods---pyrolysis-combustion flow calorimetry (PCFC), simultaneous thermal analysis (STA) and pyrolysis GC/MS---have been combined to fully characterize the thermal decomposition and flammability of polymers and polymer composites. Thermal stability, mass loss rate, char yield and properties of decomposition volatiles were found to be the most important parameters in determining polymer flammability. Most polymers decompose by either an unzipping or a random chain scission mechanism with an endothermic decomposition of 100--900 J/g. Aromatic or heteroaromatic rings, conjugated double or triple bonds and heteroatoms such as halogens, N, O, S, P and Si are the basic structural units for fire-resistant polymers. The flammability of polymers can also be successfully estimated by combining pyrolysis GC/MS results or chemical structures with TGA results. The thermal decomposition and flammability of two groups of inherently fire-resistant polymers---poly(hydroxyamide) (PHA) and its derivatives, and bisphenol C (BPC II) polyarylates---have been systematically studied. PHA and most of its derivatives have extremely low heat release rates and very high char yields upon combustion. PHA and its halogen derivatives can completely cyclize into quasi-polybenzoxazole (PBO) structures at low temperatures. However, the methoxy and phosphate derivatives show a very different behavior during decomposition and combustion. Molecular modeling shows that the formation of an enol intermediate is the rate-determining step in the thermal cyclization of PHA. BPC II-polyarylate is another extremely flame-resistant polymer. It can be used as an efficient flame-retardant agent in copolymers and blends. From PCFC results, the total heat of combustion of these copolymers or blends

  1. Nanoporous polymer electrolyte

    SciTech Connect

    Elliott, Brian; Nguyen, Vinh

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  2. Dynamic covalent polymers

    PubMed Central

    García, Fátima

    2016-01-01

    ABSTRACT This Highlight presents an overview of the rapidly growing field of dynamic covalent polymers. This class of polymers combines intrinsic reversibility with the robustness of covalent bonds, thus enabling formation of mechanically stable, polymer‐based materials that are responsive to external stimuli. It will be discussed how the inherent dynamic nature of the dynamic covalent bonds on the molecular level can be translated to the macroscopic level of the polymer, giving access to a range of applications, such as stimuli‐responsive or self‐healing materials. A primary distinction will be made based on the type of dynamic covalent bond employed, while a secondary distinction will be based on the consideration whether the dynamic covalent bond is used in the main chain of the polymer or whether it is used to allow side chain modification of the polymer. Emphasis will be on the chemistry of the dynamic covalent bonds present in the polymer, in particular in relation to how the specific (dynamic) features of the bond impart functionality to the polymer material, and to the conditions under which this dynamic behavior is manifested. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3551–3577. PMID:27917019

  3. High performance polymer development

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.

    1991-01-01

    The term high performance as applied to polymers is generally associated with polymers that operate at high temperatures. High performance is used to describe polymers that perform at temperatures of 177 C or higher. In addition to temperature, other factors obviously influence the performance of polymers such as thermal cycling, stress level, and environmental effects. Some recent developments at NASA Langley in polyimides, poly(arylene ethers), and acetylenic terminated materials are discussed. The high performance/high temperature polymers discussed are representative of the type of work underway at NASA Langley Research Center. Further improvement in these materials as well as the development of new polymers will provide technology to help meet NASA future needs in high performance/high temperature applications. In addition, because of the combination of properties offered by many of these polymers, they should find use in many other applications.

  4. Novel 4-arm poly(ethylene glycol)-block-poly(anhydride-esters) amphiphilic copolymer micelles loading curcumin: preparation, characterization, and in vitro evaluation.

    PubMed

    Lv, Li; Shen, Yuanyuan; Li, Min; Xu, Xiaofen; Li, Mingna; Guo, Shengrong; Huang, Shengtang

    2013-01-01

    A novel 4-arm poly(ethylene glycol)-block-poly(anhydride-esters) amphiphilic copolymer (4-arm PEG-b-PAE) was synthesized by esterization of 4-arm poly(ethylene glycol) and poly(anhydride-esters) which was obtained by melt polycondensation of α -, ω -acetic anhydride terminated poly(L-lactic acid). The obtained 4-arm PEG-b-PAE was characterized by (1)H-NMR and gel permeation chromatography. The critical micelle concentration of 4-arm PEG-b-PAE was 2.38 μg/mL. The curcumin-loaded 4-arm PEG-b-PAE micelles were prepared by a solid dispersion method and the drug loading content and encapsulation efficiency of the micelles were 7.0% and 85.2%, respectively. The curcumin-loaded micelles were spherical with a hydrodynamic diameter of 151.9 nm. Curcumin was encapsulated within 4-arm PEG-b-PAE micelles amorphously and released from the micelles, faster in pH 5.0 than pH 7.4, presenting one biphasic drug release pattern with rapid release at the initial stage and slow release later. The hemolysis rate of the curcumin-loaded 4-arm PEG-b-PAE micelles was 3.18%, which was below 5%. The IC50 value of the curcumin-loaded micelles against Hela cells was 10.21 μg/mL, lower than the one of free curcumin (25.90 μg/mL). The cellular uptake of the curcumin-loaded micelles in Hela cell increased in a time-dependent manner. The curcumin-loaded micelles could induce G2/M phase cell cycle arrest and apoptosis of Hela cells.

  5. Electrostatic processing of polymers and polymer composites

    NASA Astrophysics Data System (ADS)

    Sanders, Elliot Howard

    2005-11-01

    Polymers are a broad class of molecules whose use in modern life is undeniable ranging from automobile parts to pharmaceuticals. One method applicable to polymer material production is known as electrostatic processing which includes electrospraying, used to produce films or microparticles, and electrospinning, which can be used to produce fibers or non-woven materials. Electrostatic processing typically results in products with droplet or fiber diameters on the micron or nanometer scale. We have sought to develop novel polymeric materials and composites using electrostatic processing. The end uses of these materials were diverse, and included controlled release of drugs, microencapsulation of proteins and enzymes, provision of molecular cues for directed cell growth, hydronium ion transport, and electrically conductive polymer and catalytically active composites. We have successfully demonstrated that electrostatic processing can be used to produce a wide variety of functionally active polymer based materials with significant commercial, medical, and scientific potential.

  6. Non-woven fibrous materials with antibacterial properties prepared by tailored attachment of quaternized chitosan to electrospun mats from maleic anhydride copolymer.

    PubMed

    Ignatova, Milena; Petkova, Zhanina; Manolova, Nevena; Markova, Nadya; Rashkov, Iliya

    2012-01-01

    In order to impart antibacterial properties to microfibrous electrospun materials from styrene/maleic anhydride copolymers, quaternized chitosan derivatives (QCh) containing alkyl substituents of different chain lengths are covalently attached to the mats. A complete inhibition of the growth of bacteria, S. aureus (Gram-positive) and E. coli (Gram-negative), for a contact time of 30–120 min or a decrease of the bacterial titer by 2–3 log units is observed depending on the quaternization degree, the chain length of the alkyl substituent, and the molar mass of QCh. The modified mats are also effective in suppressing the adhesion of pathogenic S. aureus bacteria.

  7. Quantum dots as templates for self-assembly of photoswitchable polymers: small, dual-color nanoparticles capable of facile photomodulation.

    PubMed

    Díaz, Sebastián A; Giordano, Luciana; Azcárate, Julio C; Jovin, Thomas M; Jares-Erijman, Elizabeth A

    2013-02-27

    A photomodulatable amphiphilic polymer has been synthesized with a backbone of poly[isobutylene-alt-maleic anhydride] and pendant dodecyl alkyl chains, Lucifer Yellow (LY) fluorescent probes, and diheteroarylethenes photochromic (PC) groups. The latter serve as reversible UV-activated FRET acceptors for the LY donors. We characterized the spectral and switching properties of the polymer in an organic solvent (CHCl(3)). In an aqueous medium the polymer forms polymersomes, constituting fluorescence probes ~75 nm in diameter. Self-assembly of the polymer on the surface of a quantum dot (QD) serving as a template creates a dual-color photoswitchable nanoparticle (psNP) with improved properties due to the increase in polymer density and efficiency of PC photoconversion. The psNP exhibits a second QD red emission band that functions as an internal standard requiring only a single excitation wavelength, and is much reduced in size (<20 nm diameter) compared to the polymersomes. The QD template also greatly increases the depth of modulation by photochromic FRET of the LY emission monitored by both steady-state and time-resolved (lifetime) fluorescence (from 20%→70%, and from 12%→55%, respectively).

  8. Solubilization and purification of recombinant modified C-reactive protein from inclusion bodies using reversible anhydride modification.

    PubMed

    Potempa, Lawrence A; Yao, Zhen-Yu; Ji, Shang-Rong; Filep, János G; Wu, Yi

    . Herein, we describe a method using anhydride reagents to effectively solubilize rmCRP and allow for chromatographic purification in high yield and free of contaminating endotoxin. Furthermore, the purified rmCRP reagent represents an excellent comparable protein to the biologically produced mCRP and as a distinctive reagent from pCRP. Deciphering the true function of CRP in both health and disease requires a knowledge, understanding, and reliable supply of each of its structures so to define the distinctive effects of each on the body's response to tissue damaging events.

  9. Frontiers in polymer chemistry.

    PubMed

    Schlüter, A Dieter

    2013-01-01

    The article shows how the initial concept of Staudinger on linear macromolecules was expanded topologically by increasing the cross-section diameter of polymer chains and by introducing sheet polymers with planar rather than the commonly known linear repeat units. The two concrete projects addressed are the synthesis of dendronized and of two-dimensional polymers. It is explained how these novel macromolecules were achieved and which obstacles had to be overcome but also where these frontiers in polymer chemistry might lead to new insights in polymer science in general and novel applications in particular. The article also provides insights into analytical issues because both target macromolecules are in an extraordinarily high molar mass range and contrast/sensitivity issues can turn rather serious in particular for the two-dimensional polymers.

  10. CO2 -Responsive polymers.

    PubMed

    Lin, Shaojian; Theato, Patrick

    2013-07-25

    This Review focuses on the recent progress in the area of CO2 -responsive polymers and provides detailed descriptions of these existing examples. CO2 -responsive polymers can be categorized into three types based on their CO2 -responsive groups: amidine, amine, and carboxyl groups. Compared with traditional temperature, pH, or light stimuli-responsive polymers, CO2 -responsive polymers provide the advantage to use CO2 as a "green" trigger as well as to capture CO2 directly from air. In addition, the current challenges of CO2 -responsive polymers are discussed and the different solution methods are compared. Noteworthy, CO2 -responsive polymers are considered to have a prosperous future in various scientific areas.

  11. Thermally conductive polymers

    NASA Technical Reports Server (NTRS)

    Byrd, N. R.; Jenkins, R. K.; Lister, J. L. (Inventor)

    1971-01-01

    A thermally conductive polymer is provided having physical and chemical properties suited to use as a medium for potting electrical components. The polymer is prepared from hydroquinone, phenol, and formaldehyde, by conventional procedures employed for the preparation of phenol-formaldehyde resins. While the proportions of the monomers can be varied, a preferred polymer is formed from the monomers in a 1:1:2.4 molar or ratio of hydroquinone:phenol:formaldehyde.

  12. High Performance Polymers

    NASA Technical Reports Server (NTRS)

    Venumbaka, Sreenivasulu R.; Cassidy, Patrick E.

    2003-01-01

    This report summarizes results from research on high performance polymers. The research areas proposed in this report include: 1) Effort to improve the synthesis and to understand and replicate the dielectric behavior of 6HC17-PEK; 2) Continue preparation and evaluation of flexible, low dielectric silicon- and fluorine- containing polymers with improved toughness; and 3) Synthesis and characterization of high performance polymers containing the spirodilactam moiety.

  13. Predictive aging of polymers

    NASA Technical Reports Server (NTRS)

    Cuddihy, Edward F. (Inventor); Willis, Paul B. (Inventor)

    1990-01-01

    A method of predicting aging of polymers operates by heating a polymer in the outdoors to an elevated temperature until a change of property is induced. The test is conducted at a plurality of temperatures to establish a linear Arrhenius plot which is extrapolated to predict the induction period for failure of the polymer at ambient temperature. An Outdoor Photo Thermal Aging Reactor (OPTAR) is also described including a heatable platen for receiving a sheet of polymer, means to heat the platen and switching means such as a photoelectric switch for turning off the heater during dark periods.

  14. Predictive aging of polymers

    NASA Technical Reports Server (NTRS)

    Cuddihy, Edward F. (Inventor); Willis, Paul B. (Inventor)

    1989-01-01

    A method of predicting aging of polymers operates by heating a polymer in the outdoors to an elevated temperature until a change of property is induced. The test is conducted at a plurality of temperatures to establish a linear Arrhenius plot which is extrapolated to predict the induction period for failure of the polymer at ambient temperature. An Outdoor Photo Thermal Aging Reactor (OPTAR) is also described including a heatable platen for receiving a sheet of polymer, means to heat the platen, and switching means such as a photoelectric switch for turning off the heater during dark periods.

  15. Microstructure Development in Polymers.

    DTIC Science & Technology

    1981-05-12

    J. S. Lin, R. W. Hendricks, J. Petermann , and R. M. Gohil, J. Polymer Sci., Polym. Phys. Ed., 19, 609 (1981). 8. J. Petermann , J. M. Schultz, R. M...Gohil, R. W. Hendricks, and J. S. Lin, submitted to Polymer. 9. J. Rau, R. M. Gohil, J. Petermann , and J. M. Schultz, Colloid & Polymer Sci., 259, 241...1981). 10. J. Petermann , J. M. Schultz, R. W. Hendricks, and J. S. Lin, J. Mater. Sci., 16, 265 (1981). 11. K. M. Gupte, Ph.D. Dissertation, Univ. of

  16. Polymers for engineering applications

    SciTech Connect

    Seymour, R.B.

    1987-01-01

    This book provides an introduction to the world of engineering plastics. It discusses the polymers, their properties strengths and limitations. There are 11 chapters, organized so that each chapter builds on the knowledge of the previous material. Coverage includes important polymer concepts, such as molecular structure, bonding, morphology and molecular weight, and polymer properties, such as thermal expansion, thermal transition, electrical properties and viscoelasticity. Details are provided on methods of processing fabrication and on specific families of polymers. The general-purpose polymers are discussed, such as natural and synthetic rubbers, rayon, acrylic and alkyd coatings, polyethylene, polystyrene and polyvinyl chloride (PVC). There's information on high-performance polymers - fibers, elastomers, and coatings. A thorough explanation of the characteristics and qualities of nylons, polyesters, polyimides, neoprene, silicones, polyurethanes and other polymers is given in the same section. Functional polymers with special properties, such as photoconductivity, electric conductivity, piezoelectricity, light sensitivity, and ion exchange; and polymers that are superior to general-purpose plastics, such as ABS, filled polypropylene, and glass-reinforced plastics, are also covered.

  17. Adhesion of Polymer Vesicles

    NASA Astrophysics Data System (ADS)

    Lin, John J.; Bates, Frank S.; Hammer, Daniel A.; Silas, James A.

    2005-07-01

    The adhesion and bending modulus of polybutadiene-poly(ethylene oxide) block copolymer vesicles made from a bidisperse mixture of polymers is measured using micropipette aspiration. The adhesion energy between biotinylated vesicles and avidin beads is modeled by incorporating the extension of the adhesive ligands above the surface brush of the vesicle according to the blob model of bidisperse polymer mixtures of Komura and Safran assuming the polymer brush at the surface of the vesicle is compact. The same model accurately reproduces the scaling of the bending modulus with polymer composition.

  18. Energy filtering transmission electron microscopy immunocytochemistry and antigen retrieval of surface layer proteins from Tannerella forsythensis using microwave or autoclave heating with citraconic anhydride.

    PubMed

    Moriguchi, K; Mitamura, Y; Iwami, J; Hasegawa, Y; Higuchi, N; Murakami, Y; Maeda, H; Yoshimura, F; Nakamura, H; Ohno, N

    2012-11-01

    Tannerella forsythensis (Bacteroides forsythus), an anaerobic Gram-negative species of bacteria that plays a role in the progression of periodontal disease, has a unique bacterial protein profile. It is characterized by two unique protein bands with molecular weights of more than 200 kDa. It also is known to have a typical surface layer (S-layer) consisting of regularly arrayed subunits outside the outer membrane. We examined the relationship between high molecular weight proteins and the S-layer using electron microscopic immunolabeling with chemical fixation and an antigen retrieval procedure consisting of heating in a microwave oven or autoclave with citraconic anhydride. Immunogold particles were localized clearly at the outermost cell surface. We also used energy-filtering transmission electron microscopy (EFTEM) to visualize 3, 3'-diaminobenzidine tetrahydrochloride (DAB) reaction products after microwave antigen retrieval with 1% citraconic anhydride. The three-window method for electron spectroscopic images (ESI) of nitrogen by the EFTEM reflected the presence of moieties demonstrated by the DAB reaction with horseradish peroxidase (HRP)-conjugated secondary antibodies instead of immunogold particles. The mapping patterns of net nitrogen were restricted to the outermost cell surface.

  19. Binary Polymer Brushes of Strongly Immiscible Polymers.

    PubMed

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  20. Triclosan antimicrobial polymers

    PubMed Central

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers that set on cooling

  1. Direct characterization of polymer encapsulated CdSe/CdS/ZnS quantum dots

    NASA Astrophysics Data System (ADS)

    Zorn, Gilad; Dave, Shivang R.; Weidner, Tobias; Gao, Xiaohu; Castner, David G.

    2016-06-01

    Surface engineering advances of semiconductor quantum dots (QDs) have enabled their application to molecular labeling, disease diagnostics and tumor imaging. For biological applications, hydrophobic core/shell QDs are transferred into aqueous solutions through the incorporation of water-solubility imparting moieties, typically achieved via direct exchange of the native surface passivating ligands or indirectly through the adsorption of polymers. Although polymeric encapsulation has gained wide acceptance, there are few reports addressing the characterization of the adsorbed polymers and existing theoretical analyses are typically based on simple geometric models. In this work, we experimentally characterize and quantify water-soluble QDs prepared by adsorption of amphiphilic poly(maleic anhydride-alt-1-tetradecene) (PMAT, MW ~ 9000) onto commercially available CdSe/CdS/ZnS (CdSe/CdS/ZnS-PMAT). Using X-ray photoelectron spectroscopy (XPS) we determined that ~ 15 PMAT molecules are adsorbed onto each QD and sum frequency generation (SFG) vibrational spectra were utilized to investigate the mechanism of interaction between PMAT molecules and the QD surface. Importantly, when employed together, these techniques constitute a platform with which to investigate any polymer-nanoparticle complex in general.

  2. Polymer based tunneling sensor

    NASA Technical Reports Server (NTRS)

    Cui, Tianhong (Inventor); Wang, Jing (Inventor); Zhao, Yongjun (Inventor)

    2006-01-01

    A process for fabricating a polymer based circuit by the following steps. A mold of a design is formed through a lithography process. The design is transferred to a polymer substrate through a hot embossing process. A metal layer is then deposited over at least part of said design and at least one electrical lead is connected to said metal layer.

  3. Melons are Branched Polymers

    NASA Astrophysics Data System (ADS)

    Gurau, Razvan; Ryan, James P.

    2014-11-01

    Melonic graphs constitute the family of graphs arising at leading order in the 1/N expansion of tensor models. They were shown to lead to a continuum phase, reminiscent of branched polymers. We show here that they are in fact precisely branched polymers, that is, they possess Hausdorff dimension 2 and spectral dimension 4/3.

  4. Advanced Polymer Network Structures

    DTIC Science & Technology

    2016-02-01

    13. SUPPLEMENTARY NOTES 14. ABSTRACT Polymer networks and gels are important classes of materials for defense applications . In an effort to......it is no longer needed. Do not return it to the originator. ARL-TR-7612 ● FEB 2016 US Army Research Laboratory Advanced Polymer

  5. Polymers Are Everywhere.

    ERIC Educational Resources Information Center

    Seymour, Raymond B.

    1988-01-01

    Describes the history of the human understanding of polymers from alchemy to modern times. Discusses renaissance chemistry, polymers in the nineteenth century, synthetic elastomers, thermoplastic elastomers, fibers, coatings, adhesives, derivatives of natural rubber, thermosets, step-reaction, and chain polymerization. (CW)

  6. Radioluminescent polymer lights

    SciTech Connect

    Jensen, G.A.; Nelson, D.A.; Molton, P.M.

    1990-09-01

    The preparation of radioluminescent light sources where the tritium is located on the aryl-ring in a polymer has been demonstrated with deuterium/tritium substitution. This report discusses tests, results, and future applications of radioluminescent polymers. 10 refs. (FI)

  7. Polymers at membranes

    NASA Astrophysics Data System (ADS)

    Breidenich, Markus

    2000-11-01

    The surface of biological cells consists of a lipid membrane and a large amount of various proteins and polymers, which are embedded in the membrane or attached to it. We investigate how membranes are influenced by polymers, which are anchored to the membrane by one end. The entropic pressure exerted by the polymer induces a curvature, which bends the membrane away from the polymer. The resulting membrane shape profile is a cone in the vicinity of the anchor segment and a catenoid far away from it. The perturbative calculations are confirmed by Monte-Carlo simulations. An additional attractive interaction between polymer and membrane reduces the entropically induced curvature. In the limit of strong adsorption, the polymer is localized directly on the membrane surface and does not induce any pressure, i.e. the membrane curvature vanishes. If the polymer is not anchored directly on the membrane surface, but in a non-vanishing anchoring distance, the membrane bends towards the polymer for strong adsorption. In the last part of the thesis, we study membranes under the influence of non-anchored polymers in solution. In the limit of pure steric interactions between the membrane and free polymers, the membrane curves towards the polymers (in contrast to the case of anchored polymers). In the limit of strong adsorption the membrane bends away from the polymers. Die Oberfläche biologischer Zellen besteht aus einer Lipidmembran und einer Vielzahl von Proteinen und Polymeren, die in die Membran eingebaut sind. Die Beeinflussung der Membran durch Polymere, die mit einem Ende an der Membran verankert sind, wird im Rahmen dieser Arbeit anhand eines vereinfachten biomimetischen Systems studiert. Der entropische Druck, den das Polymer durch Stöße auf die Membran ausübt, führt dazu, dass sich die Membran vom Polymer weg krümmt. Die resultierende Membranform ist ein Kegel in der Nähe des Ankers und ein Katenoid in grossem Abstand vom Ankerpunkt. Monte Carlo-Simulationen best

  8. Polymer Crystallization under Confinement

    NASA Astrophysics Data System (ADS)

    Floudas, George

    Recent efforts indicated that polymer crystallization under confinement can be substantially different from the bulk. This can have important technological applications for the design of polymeric nanofibers with tunable mechanical strength, processability and optical clarity. However, the question of how, why and when polymers crystallize under confinement is not fully answered. Important studies of polymer crystallization confined to droplets and within the spherical nanodomains of block copolymers emphasized the interplay between heterogeneous and homogeneous nucleation. Herein we report on recent studies1-5 of polymer crystallization under hard confinement provided by model self-ordered AAO nanopores. Important open questions here are on the type of nucleation (homogeneous vs. heterogeneous), the size of critical nucleus, the crystal orientation and the possibility to control the overall crystallinity. Providing answers to these questions is of technological relevance for the understanding of nanocomposites containing semicrystalline polymers. In collaboration with Y. Suzuki, H. Duran, M. Steinhart, H.-J. Butt.

  9. Rapid Polymer Sequencer

    NASA Technical Reports Server (NTRS)

    Stolc, Viktor (Inventor); Brock, Mathew W. (Inventor)

    2011-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal or transverse direction at the tip, a polymer sequence is passed through the tip, and a change in an electrical current signal is measured as each polymer component passes through the tip. Each measured change in electrical current signals is compared with a database of reference signals, with each reference signal identified with a polymer component, to identify the unknown polymer component. The tip preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  10. Porous polymer media

    DOEpatents

    Shepodd, Timothy J.

    2002-01-01

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

  11. Modulated in Vitro Biocompatibility of a Unique Cross-Linked Salicylic Acid-Poly(ε-caprolactone)-Based Biodegradable Polymer.

    PubMed

    Bhaskar, Nitu; Padmavathy, Nagarajan; Jain, Shubham; Bose, Suryasarathi; Basu, Bikramjit

    2016-11-02

    Herein, we report the development of a unique architecture by chemically cross-linking salicylic acid (SA)-based poly(anhydride ester) onto a biodegradable amine-functionalized poly(caprolactone) (PCL), using lactic acid as a spacer. The ester and amide linkages in the SA-PCL polymer, synthesized through melt condensation, were confirmed by NMR and FT-IR spectroscopic techniques. The enzymatic and nonenzymatic hydrolytic degradation profile exhibited linear degradation kinetics over an extended time period (>5 weeks). The compatibility and growth of C2C12 myoblast cells were found to be significantly improved on the fast-degrading SA-PCL substrates compared to those over neat PCL and amine-functionalized PCL. Further, the decreased red blood cell damage, illustrated by 0.39% hemolysis activity and a minimal number of platelet adhesion on a SA-PCL polymeric surface confirmed good hemocompatibility of the as-synthesized polymer. Together with a moderate bactericidal property, the spectrum of properties of this novel polymer can be attributed to the synergistic effect of the presence of chemical moieties of SA and amine groups in PCL. In summary, it is considered that a SA-PCL-based cross-linked composite can be utilized as a new biodegradable polymer.

  12. Modification of polylactide bioplastic using hyperbranched polymer based nanostructures

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Rahul

    maximum average matrix ligament thickness was 114 nm for a toughened polylactide nanoblend and correlated well with the theoretical prediction of the matrix ligament thickness. Fourier transform infrared spectroscopy and dynamic mechanical thermal analysis proved the crosslinking of the HBP phase in the PLA matrix. The crosslinked HBP was effective at hydroxyl (-OH) to anhydride molar ratios of: 2:1, 1:1 or 1:2. The glass transition temperature values of the crosslinked HBP phase at these molar ratios were observed to deviate from the predictions made by the Fox equation. The hydrophilic nature of the hyperbranched polymer was altered to hydrophobic by incorporation of polyanhydride crosslinker, as demonstrated by the increase in the contact angle with water. Rheological studies showed that there was a network formation in the PLA matrix after in-situ crosslinking of HBP. The HBP was found to reduce the melt viscosity of PLA dramatically and this effect was maintained even after its in-situ crosslinking in the PLA matrix. Finally, the current research unwraps the new opportunities provided by the unique physical and chemical properties of highly functional hyperbranched polymers in generating new nanostructured multiphase polymer systems with enhanced properties.

  13. A highly efficient green synthesis of N-alkyl 2-[(2-oxo-2-aryl ethyl) amino] benzamide derivatives from reaction of isatoic anhydride, primary amines and 2-bromoacethophenone.

    PubMed

    Sabbaghan, Maryam; Hossaini, Zinatossadat

    2012-11-01

    N-alkyl 2-[(2-oxo-2-aryl ethyl)amino] benzamide derivatives have been synthesized in high yields. This involves three-component reaction of isatoic anhydride, primary amines in the presence of 2-bromoacethophenone derivatives. The reaction workup is simple and the products can be easily separated from the reaction mixture.

  14. Polymers pushing Polymers: Polymer Mixtures in Thermodynamic Equilibrium with a Pore.

    PubMed

    Podgornik, R; Hopkins, J; Parsegian, V A; Muthukumar, M

    2012-11-13

    We investigate polymer partitioning from polymer mixtures into nanometer size cavities by formulating an equation of state for a binary polymer mixture assuming that only one (smaller) of the two polymer components can penetrate the cavity. Deriving the partitioning equilibrium equations and solving them numerically allows us to introduce the concept of "polymers-pushing-polymers" for the action of non-penetrating polymers on the partitioning of the penetrating polymers. Polymer partitioning into a pore even within a very simple model of a binary polymer mixture is shown to depend in a complicated way on the composition of the polymer mixture and/or the pore-penetration penalty. This can lead to enhanced as well as diminished partitioning, due to two separate energy scales that we analyse in detail.

  15. Low Dielectric Polymers

    NASA Technical Reports Server (NTRS)

    Venumbaka, Sreenivasulu R.; Cassidy, Patrick E.

    2002-01-01

    This report summarizes results obtained from research funded through Research Cooperative Agreement No. NCC-1-01033-"Low Dielectric Polymers" (from 5/10/01 through 5/09/02). Results are reported in three of the proposed research areas (Tasks 1-3 in the original proposal): (1) Repeat and confirm the preparation and properties of the new alkyl-substituted PEK, 6HC17-PEK, (2) Prepare and evaluate polymers derived from a highly fluorinated monomer, and (3) Prepare and evaluate new silicon and/or fluorine-containing polymers expected to retain useful properties at low temperature.

  16. Elasticity of semiflexible polymers.

    PubMed

    Samuel, Joseph; Sinha, Supurna

    2002-11-01

    We present a method for solving the wormlike chain model for semiflexible polymers to any desired accuracy over the entire range of polymer lengths. Our results are in excellent agreement with recent computer simulations and reproduce important qualitatively interesting features observed in simulations of polymers of intermediate lengths. We also make a number of predictions that can be tested in a variety of concrete experimental realizations. The expected level of finite size fluctuations in force-extension curves is also estimated. This study is relevant to mechanical properties of biological molecules.

  17. Soluble porphyrin polymers

    DOEpatents

    Gust, Jr., John Devens; Liddell, Paul Anthony

    2015-07-07

    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  18. Effect of pre-irradiation PPO-grafted maleic anhydride on structure and properties of PPO-g-MAH/PA66 blends

    NASA Astrophysics Data System (ADS)

    Li, Wenfei; Yao, Zhanhai; Yao, Ruixiang; Li, Xuan; Liu, Shumei

    2014-04-01

    The pre-irradiation polyphenylene oxide (PPO)-graft-maleic anhydride (PPO-g-MAH) was carried out by reactive extrusion. The chemical structure of PPO-g-MAH was characterized by means of Fourier-transform infrared spectroscopy. The wettability of PPO-g-MAH was characterized by the contact angle method. The blends of PPO-g-MAH/polyamide 66 (PA66) were prepared. Compared with the PPO/PA66 blends, mechanical properties of PPO-g-MAH/PA66 blends were distinctly improved. Smaller dispersed particle sizes with narrower distribution were found in PPO-g-MAH/PA66 blends, via field-emitted scanning electron microscopy. Rheological properties of PPO-g-MAH/PA66 blends were studied with a rotational rheometer.

  19. Enzymatic synthesis and modification of polymers and nanomaterials

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Yun

    Biocatalysis perform chemical reactions in mild reaction environments with high catalytic rates to transform a particular set of substrates to specific reaction products. The broad substrate specificity and exquisite selectivity of enzymes have made them applicable in diverse applications. This thesis work explores biocatalysis in varied modes of synthesis, discovery, and also functional application as nanomaterial immobilized catalysts. First, biocatalysis is explored as a synthesis tool to generate carbohydrate-based polymers with regioselective acylation of the disaccharides sucrose and trehalose with diester derivatives. Sugar-based polymers are difficult to synthesize chemically due to the presence of multiple hydroxyl moieties and a selective catalytic route enhances the systematic incorporation of sugars into the polymer to rationally alter physicochemical properties. The sugar esters (containing reactive end groups) are polymerized with a variety of diols and enzymes in diverse reaction solvent conditions. Biocatalysis is well suited to becoming a discovery tool for new materials. Enzyme-catalyzed reactions are performed in 96-well microtiter plates to implement a combinatorial methodology to polymer synthesis. Two libraries are generated: the first is synthesized with bifunctional monomers under varying solvent conditions and multiple enzymes to identify optimal reaction conditions. The second library includes diverse polyols (sugars, nucleic acids, and steroids) to demonstrate the positional selectivity and broad reactivity of enzyme-mediated polymerization. The last part of this work incorporates enzymes onto nanoscale materials for functional material synthesis and modification. Silicon nanopillars are used as three-dimensional supports for high-density enzyme immobilization. Maleic anhydride coupling chemistries are explored for attachment and enzyme kinetic measurements are compared to enzyme immobilized on flat supports with equal projected surface

  20. Synthesis and characterization of triglyceride based thermosetting polymers

    NASA Astrophysics Data System (ADS)

    Can, Erde

    2005-07-01

    Plant oils, which are found in abundance in all parts of the world and are easily replenished annually, have the potential to replace petroleum as a chemical feedstock for making polymers. Within the past few years, there has been growing interest to use triglycerides as the basic constituent of thermosetting polymers with the necessary rigidity, strength and glass transition temperatures required for engineering applications. Plant oils are not polymerizable in their natural form, however various functional groups that can polymerize can easily be attached to the triglyceride structure making them ideal cross-linking monomers for thermosetting liquid molding resins. Through this research project a number of thermosetting liquid molding resins based on soybean and castor oil, which is a specialty oil with hydroxyls on its fatty acids, have been developed. The triglyceride based monomers were prepared via the malination of the alcoholysis products of soybean and castor oil with various polyols, such as pentaerythritol, glycerol, and Bisphenol A propoxylate. The malinated glycerides were then cured in the presence of a reactive diluent, such as styrene, to form rigid glassy materials with a wide range of properties. In addition to maleate half-esters, methacrylates were also introduced to the glyceride structure via methacrylation of the soybean oil glycerolysis product with methacrylic anhydride. This product, which contains methacrylic acid as by-product, and its blends with styrene also gave rigid materials when cured. The triglyceride based monomers were characterized via conventional spectroscopic techniques. Time resolved FTIR analysis was used to determine the curing kinetics and the final conversions of polymerization of the malinated glyceride-styrene blends. Dynamic Mechanical Analysis (DMA) was used to determine the thermomechanical behavior of these polymers and other mechanical properties were determined via standard mechanical tests. The use of lignin

  1. Hydrogen-bonding in 2-aminobenzoyl-alpha-chymotrypsin formed by acylation of the enzyme with isatoic anhydride: IR and mass spectroscopic studies.

    PubMed

    Goodall, Jonathan J; Booth, Victoria K; Ashcroft, Alison E; Wharton, Christopher W

    2002-01-04

    The acyl-enzyme formed upon acylation of alpha-chymotrypsin with isatoic anhydride has been characterised by infrared spectroscopy. Acylation at pH 7 to yield the 2-aminobenzoyl-enzyme is rapid (k = 5.57x 10(-2)s(-1)), while deacylation is much slower (k =3.7 x 10(-5)10(-2) (s-). The [1C=O]-labelled form of isatoic anhydride has been synthesised, to allow construction of [72C=O]- minus [13C=O]difference spectra; these highlight the carbonyl absorbance of the ligand and eliminate spectral effects that arise from protein perturbation. The ester carbonyl band of the acyl-enzyme absorbs at a wavenumber of 1695cm(-1) and has been shown by deconvolution analysis to represent a single, well-defined conformation. Model studies of ethyl 2-aminobenzoate in a range of solvents show that its carbonyl group is in a hexane-like environment (that is, very nonpolar). It is proposed that the low wavenumber of the carbonyl absorbance arises from the presence of an internal hydrogen bond between the 2-amino group and the ester carbonyl oxygen; this leads to polarisation of the carbonyl group both in the enzyme and in nonpolar solvents. However, in view of the slow deacylation, it is clear that the acyl group is in a nonproductive conformation, with no interaction with the oxyanion hole, and that deacylation occurs from this form or from a minor, invisible form. The infrared data have been supported by kinetic electrospray mass spectroscopic measurements, which demonstrate that the acyl-enzyme is that previously anticipated, and by molecular modelling of 2-aminobenzoyl-alpha-chymotrypsin. It is concluded from pH-dependence measurements that general base catalysis by the 2-amino group is not involved in deacylation.

  2. Solvent effects in acid-catalyzed dehydration of the Diels-Alder cycloadduct between 2,5-dimethylfuran and maleic anhydride

    NASA Astrophysics Data System (ADS)

    Salavati-fard, Taha; Caratzoulas, Stavros; Doren, Douglas J.

    2017-03-01

    Dehydration of the cycloadduct produced from the Diels-Alder reaction between 2,5-dimethylfuran and maleic anhydride to 3,6-dimethylphthalic anhydride exemplifies an important step in producing platform chemicals from biomass. The mechanisms of dehydration and catalytic effects of Lewis and Brønsted acids are investigated with density functional theory. The uncatalyzed reaction has a very high activation barrier (68.7 kcal/mol) in the gas phase and it is not significantly affected by solvation. With a Lewis acid catalyst, modeled as an alkali ion, the activation barriers are reduced, but intermediates are also stabilized. The net effect in vacuum is that the energetic span, or apparent activation energy of the catalytic cycle, is 77.9 kcal/mol, even higher than the barrier in the uncatalyzed case. In solution, however, the energetic span is reduced by as much as 20 kcal/mol, due to differences in the solvation energy of the transition states and intermediates. In the case of a Brønsted acid catalyst, modeled as a proton, the gas phase transition state energies are reduced even more than in the Lewis acid case, and there is no strong stabilization of the intermediates. The energetic span in vacuum is only 13.8 kcal/mol and is reduced even further in solution. Brønsted acid catalysis appears to be the preferred mechanism for dehydration of this cycloadduct. Since the Diels-Alder reaction that produced the molecule has previously been shown to be catalyzed by Brønsted acids, this suggests that a single catalyst could be used to accelerate both steps.

  3. Sulfonated polyphenylene polymers

    DOEpatents

    Cornelius, Christopher J.; Fujimoto, Cy H.; Hickner, Michael A.

    2007-11-27

    Improved sulfonated polyphenylene compositions, improved polymer electrolyte membranes and nanocomposites formed there from for use in fuel cells are described herein. The improved compositions, membranes and nanocomposites formed there from overcome limitations of Nafion.RTM. membranes.

  4. Driving magnetic colloidal polymers

    NASA Astrophysics Data System (ADS)

    Dempster, Joshua; Olvera de La Cruz, Monica

    Magnetic colloids are of growing interest for applications such as drug delivery and in vitro tissue growth. Recent experiments have synthesized 1D chains of magnetic colloids into permanent colloidal polymers. We study magnetic colloidal polymers theoretically and computationally under the influence of time-varying external fields and find a rich set of controllable, dynamic conformations. By iterating through a sequence of conformations, these polymers can perform mechanical functions. We discuss possible roles for these polymers beyond those considered for single colloids. This work was supported as part of the Center for Bio-Inspired Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0000989.

  5. Electroactive polymers for sensing

    PubMed Central

    2016-01-01

    Electromechanical coupling in electroactive polymers (EAPs) has been widely applied for actuation and is also being increasingly investigated for sensing chemical and mechanical stimuli. EAPs are a unique class of materials, with low-moduli high-strain capabilities and the ability to conform to surfaces of different shapes. These features make them attractive for applications such as wearable sensors and interfacing with soft tissues. Here, we review the major types of EAPs and their sensing mechanisms. These are divided into two classes depending on the main type of charge carrier: ionic EAPs (such as conducting polymers and ionic polymer–metal composites) and electronic EAPs (such as dielectric elastomers, liquid-crystal polymers and piezoelectric polymers). This review is intended to serve as an introduction to the mechanisms of these materials and as a first step in material selection for both researchers and designers of flexible/bendable devices, biocompatible sensors or even robotic tactile sensing units. PMID:27499846

  6. Covalent polymers of water.

    PubMed

    O'konski, C T

    1970-05-29

    A new covalent structural scheme for water polymers is proposed. The observed properties of "polywater" are related to the structures of the suggested homologous series of molecules. Mechanisms of formation are suggested.

  7. Dendritic Polymers for Theranostics

    PubMed Central

    Ma, Yuan; Mou, Quanbing; Wang, Dali; Zhu, Xinyuan; Yan, Deyue

    2016-01-01

    Dendritic polymers are highly branched polymers with controllable structures, which possess a large population of terminal functional groups, low solution or melt viscosity, and good solubility. Their size, degree of branching and functionality can be adjusted and controlled through the synthetic procedures. These tunable structures correspond to application-related properties, such as biodegradability, biocompatibility, stimuli-responsiveness and self-assembly ability, which are the key points for theranostic applications, including chemotherapeutic theranostics, biotherapeutic theranostics, phototherapeutic theranostics, radiotherapeutic theranostics and combined therapeutic theranostics. Up to now, significant progress has been made for the dendritic polymers in solving some of the fundamental and technical questions toward their theranostic applications. In this review, we briefly summarize how to control the structures of dendritic polymers, the theranostics-related properties derived from their structures and their theranostics-related applications. PMID:27217829

  8. Rechargeable solid polymer electrolyte battery cell

    DOEpatents

    Skotheim, Terji

    1985-01-01

    A rechargeable battery cell comprising first and second electrodes sandwiching a solid polymer electrolyte comprising a layer of a polymer blend of a highly conductive polymer and a solid polymer electrolyte adjacent said polymer blend and a layer of dry solid polymer electrolyte adjacent said layer of polymer blend and said second electrode.

  9. Carbon Nanofiber Reinforced Polymers

    DTIC Science & Technology

    2006-01-01

    2006 2. REPORT TYPE 3. DATES COVERED 00-00-2006 to 00-00-2006 4. TITLE AND SUBTITLE Carbon Nanofiber Reinforced Polymers 5a. CONTRACT NUMBER 5b...REVIEW Carbon Nanofiber Reinforced Polymers J.N. Baucom, A. Rohatgi, W.R. Pogue III, and J.P. Thomas Materials Science and Technology Division...of mass-produced and inexpensive, discontinuous carbon nanofibers to create a percolated fiber network within a polymeric matrix that will result in

  10. Amine terminated bisaspartimide polymer

    NASA Technical Reports Server (NTRS)

    Kumar, D. (Inventor); Fohlen, G. M. (Inventor); Parker, J. A. (Inventor)

    1986-01-01

    Novel amine terminated bisaspartimides are prepared by a Michael-type reaction of an aromatic bismalteimide and an aromatic diamine in an aprotic solvent. These bisaspartimides are thermally polymerized to yield tough, resinous polymers cross-lined through -NH- groups. Such polymers are useful in applications requiring materials with resistance to change at elevated temperatures, e.g., as lightweight laminates with graphite cloth, molding material prepregs, adhesives and insulating material.

  11. Functional Polymer Matrix Fibers

    DTIC Science & Technology

    2007-11-02

    the carbon nanofibers led to the deterioration of the polymeric cellulose structure. Extensive research on the surface treatment of carbon nanofibers...1 November 2003 - 14-Mar-05 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER FA8655-03-1-3042 Functional Polymer Matrix Fibres 5b. GRANT NUMBER 5c. PROGRAM...MARYLABONE RD LONDON NWl 5TH PERFORMANCE REPORT Project title: Functional polymer matrix fibers Period of performance: 1 November 2003 - 31 October 2004

  12. Polymer optical motherboard technology

    NASA Astrophysics Data System (ADS)

    Keil, N.; Yao, H.; Zawadzki, C.; Grote, N.; Schell, M.

    2008-02-01

    In this paper, different hybridly integrated optical devices including optical multiplexer/ demultiplexer and optical transceivers are described. The devices were made using polymer planar light wave circuit (P2LC) technology. Laser diodes, photodiodes, and thin-film filters have been integrated. Key issues involved in this technology, in particular the coupling between laser diodes and polymer waveguides, and between waveguides and photodiodes and also fibers are discussed.

  13. Cylodextrin Polymer Nitrate

    NASA Technical Reports Server (NTRS)

    Kosowski, Bernard; Ruebner, Anja; Statton, Gary; Robitelle, Danielle; Meyers, Curtis

    2000-01-01

    The development of the use of cyclodextrin nitrates as possible components of insensitive, high-energy energetics is outlined over a time period of 12 years. Four different types of cyclodextrin polymers were synthesized, nitrated, and evaluated regarding their potential use for the military and aerospace community. The synthesis of these novel cyclodextrin polymers and different nitration techniques are shown and the potential of these new materials is discussed.

  14. Polymer Blends. Volume 1

    DTIC Science & Technology

    1992-05-01

    polyimides, thereby potentially leading to a viable, new class of high temperature, thermoformable resins for 371 0C (7000F) applica- tions. The Polymer...PBI/PI systems exhibit miscibility which: - exhibit improved processibility over neat PBI - are thermoformable - have improved mechanical performance...new class of high temperature, thermoformable resins for 3710C (700*F) applications. The Polymer Alloy and Composite Program also established a

  15. Polymer composites and porous materials prepared by thermally induced phase separation and polymer-metal hybrid methods

    NASA Astrophysics Data System (ADS)

    Yoon, Joonsung

    phthalic anhydride. A simple method to prepare composite surfaces that can change the wettability in response to the temperature change was proposed and evaluated. Composite surfaces prepared by nanoporous alumina templates filled with polymers showed surface morphology and wettability that depend on temperature. This effect is attributed to the significant difference in thermal conductivity and the thermal expansion coefficient between the alumina and the polymers. The reversibility in thermal response depends on the properties of the polymers.

  16. Nanoimprinted polymer solar cell.

    PubMed

    Yang, Yi; Mielczarek, Kamil; Aryal, Mukti; Zakhidov, Anvar; Hu, Walter

    2012-04-24

    Among the various organic photovoltaic devices, the conjugated polymer/fullerene approach has drawn the most research interest. The performance of these types of solar cells is greatly determined by the nanoscale morphology of the two components (donor/acceptor) and the molecular orientation/crystallinity in the photoactive layer. A vertically bicontinuous and interdigitized heterojunction between donor and acceptor has been regarded as one of the ideal structures to enable both efficient charge separation and transport. Synergistic control of polymer orientation in the nanostructured heterojunction is also critical to improve the performance of polymer solar cells. Nanoimprint lithography has emerged as a new approach to simultaneously control both the heterojunction morphology and polymer chains in organic photovoltaics. Currently, in the area of nanoimprinted polymer solar cells, much progress has been achieved in the fabrication of nanostructured morphology, control of molecular orientation/crystallinity, deposition of acceptor materials, patterned electrodes, understanding of structure-property correlations, and device performance. This review article summarizes the recent studies on nanoimprinted polymer solar cells and discusses the outstanding challenges and opportunities for future work.

  17. Rapid Polymer Sequencer

    NASA Technical Reports Server (NTRS)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  18. Polymer and composite polymer slot waveguides

    NASA Astrophysics Data System (ADS)

    Hiltunen, Marianne; Fegadolli, William S.; Lira, Hugo L. R.; Vahimaa, Pasi; Hiltunen, Jussi; Aikio, Sanna; Almeida, Vilson R.; Karioja, Pentti

    2014-05-01

    A fully polymer slot Young interferometer operating at 633 nm wavelength was fabricated by using nanoimprint molding method. The phase response of the interference pattern was measured with several concentrations of glucose-water solutions, utilizing both TE and TM polarization states. The sensor was experimentally found to detect a bulk refractive index change of 6.4×10-6 RIU. Temperature dependency of silicon slot waveguide has been demonstrated to be reduced with composite slot waveguide structure. The slot filled with thermally stable polymer having negative thermo-optic coefficient showed nearly an athermal operation of silicon slot waveguide. Experimental results show that the slot waveguide geometry covered with Ormocomp has thermo-optical coefficient of 6 pm/K.

  19. Heterogeneous polymer modification: Polyolefin maleation in supercritical carbon dioxide and amorphous fluoropolymer surface modification

    NASA Astrophysics Data System (ADS)

    Hayes, Heather J.

    1999-11-01

    Three distinct heterogeneous polymer modification reactions are explored in this work. The first is a bulk reaction commonly conducted on polyolefins---the free radical addition of maleic anhydride. This reaction was run using supercritical carbon dioxide (SC CO2) as the solvent. The second was the chemical surface modification of an amorphous fluorocopolymer of tetrafluoroethylene and a perfluorodioxole monomer (Teflon AF). Several reactions were explored to reduce the surface of the fluorocopolymer for the enhancement of wettability. The last modification was also on Teflon AF and involved the physical modification of the surface through the transport polymerization of xylylene in order to synthesize a novel bilayer membrane. The bulk maleation of poly-4-methyl-1-pentene (PMP) was the focus of the first project. SC CO2 was utilized as both solvent and swelling agent to promote this heterogeneous reaction and led to successful grafting of anhydride groups on both PMP and linear low density polyethylene. Varying the reaction conditions and reagent concentrations allowed optimization of the reaction. The grafted anhydride units were found to exist as single maleic and succinic grafts, and the PMP became crosslinked upon maleation. The surface of a fluoropolymer can be difficult to alter. An examination of three reactions was made to determine the reactivity of Teflon AF: sodium naphthalenide treatment (Na-Nap), aluminum metal modification through deposition and dissolution, and mercury/ammonia photosensitization. The fluorocopolymer with the lower perfluorodioxole percentage was found to be more reactive towards modification with the Na-Nap treatment. The other modification reactions appeared to be nearly equally reactive toward both fluorocopolymers. The functionality of the Na-Nap-treated surface was examined in detail with the use of several derivatization reactions. In the final project, an asymmetric gas separation membrane was synthesized using Teflon AF as

  20. Precursor polymer compositions comprising polybenzimidazole

    SciTech Connect

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  1. Amide side chain amphiphilic polymers disrupt surface established bacterial bio-films and protect mice from chronic Acinetobacter baumannii infection.

    PubMed

    Uppu, Divakara S S M; Samaddar, Sandip; Ghosh, Chandradhish; Paramanandham, Krishnamoorthy; Shome, Bibek R; Haldar, Jayanta

    2016-01-01

    Bacterial biofilms represent the root-cause of chronic or persistent infections in humans. Gram-negative bacterial infections due to nosocomial and opportunistic pathogens such as Acinetobacter baumannii are more difficult to treat because of their inherent and rapidly acquiring resistance to antibiotics. Due to biofilm formation, A. baumannii has been noted for its apparent ability to survive on artificial surfaces for an extended period of time, therefore allowing it to persist in the hospital environment. Here we report, maleic anhydride based novel cationic polymers appended with amide side chains that disrupt surface established multi-drug resistant A. baumannii biofilms. More importantly, these polymers significantly (p < 0.0001) decrease the bacterial burden in mice with chronic A. baumannii burn wound infection. The polymers also show potent antibacterial efficacy against methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant Enterococci (VRE) and multi-drug resistant clinical isolates of A. baumannii with minimal toxicity to mammalian cells. We observe that optimal hydrophobicity dependent on the side chain chemical structure of these polymers dictate the selective toxicity to bacteria. Polymers interact with the bacterial cell membranes by causing membrane depolarization, permeabilization and energy depletion. Bacteria develop rapid resistance to erythromycin and colistin whereas no detectable development of resistance occurs against these polymers even after several passages. These results suggest the potential use of these polymeric biomaterials in disinfecting biomedical device surfaces after the infection has become established and also for the topical treatment of chronic bacterial infections.

  2. Simulations of Polymer Translocation

    NASA Astrophysics Data System (ADS)

    Vocks, H.

    2008-07-01

    Transport of molecules across membranes is an essential mechanism for life processes. These molecules are often long, and the pores in the membranes are too narrow for the molecules to pass through as a single unit. In such circumstances, the molecules have to squeeze -- i.e., translocate -- themselves through the pores. DNA, RNA and proteins are such naturally occuring long molecules in a variety of biological processes. Understandably, the process of translocation has been an active topic of current research: not only because it is a cornerstone of many biological processes, but also due to its relevance for practical applications. Translocation is a complicated process in living organisms -- the presence of chaperone molecules, pH, chemical potential gradients, and assisting molecular motors strongly influence its dynamics. Consequently, the translocation process has been empirically studied in great variety in biological literature. Study of translocation as a biophysical process is more recent. Herein, the polymer is simplified to a sequentially connected string of N monomers as it passes through a narrow pore on a membrane. The quantities of interest are the typical time scale for the polymer to leave a confining cell (the ``escape of a polymer from a vesicle'' time scale), and the typical time scale the polymer spends in the pore (the ``dwell'' time scale) as a function of N and other parameters like membrane thickness, membrane adsorption, electrochemical potential gradient, etc. Our research is focused on computer simulations of translocation. Since our main interest is in the scaling properties, we use a highly simplified description of the translocation process. The polymer is described as a self-avoiding walk on a lattice, and its dynamics consists of single-monomer jumps from one lattice site to another neighboring one. Since we have a very efficient program to simulate such polymer dynamics, which we decribe in Chapter 2, we can perform long

  3. Role of surface functionality on the formation of raspberry-like polymer/silica composite particles: Weak acid-base interaction and steric effect

    NASA Astrophysics Data System (ADS)

    Wang, Lan; Song, LinYong; Chao, ZhiYin; Chen, PengPeng; Nie, WangYan; Zhou, YiFeng

    2015-07-01

    The surface functionality of polymer microspheres is the crucial factor to determine the nucleation and growth of silica particles and to construct the organic/inorganic hierarchical structures. The objective of this work was to evaluate the surface functionality and hierarchical morphology relationship via in situ sol-gel reaction. Carboxylic-functionalized poly (styrene-co-maleic anhydride) [P(S-co-MA)], poly(ethylene glycol)-functionalized poly(styrene-co-poly(ethylene glycol) methacrylate) [P(S-co-PEGMA)], and hybrid functionalized poly(styrene-co-maleic anhydride-co-poly(ethylene glycol) methacrylate) [P(S-co-MA-co-PEGMA)] microspheres were synthesized by emulsifier-free polymerization and used as templates. The morphologies of the composite particles were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results showed that core-shell structure was obtained with P(S-co-MA) as templates; raspberry-like structure was observed by using P(S-co-MA-co-PEGMA) as templates; and no silica particles were attached onto the surface of P(S-co-PEGMA) microspheres. These results indicated that the carboxylic groups on the surface formed by hydrolysis of anhydride groups were the determinate factor to control the nucleation of silica nanoparticles, and the PEG chains on the surface can affect the growth of silica particles. In addition, the particulate films were constructed by assembling these composite particles on glass substrates and modified with dodecyltrichlorosilane, the contact angles of water on the dual-sized structured surface were up to 160°.

  4. Molecular modeling of interactions in electronic nose sensors for environmental monitoring

    NASA Technical Reports Server (NTRS)

    Shevade, A. V.; Ryan, M. A.; Homer, M. L.; Manfreda, A. M.; Yen, S. -P. S.; Zhou, H.; Manatt, K.

    2002-01-01

    We report a study aimed at understanding analyte interactions with sensors made from polymer-carbon black composite films. The sensors are used in an Electronic Nose (ENose) which is used for monitoring the breathing air quality in human habitats. The model mimics the experimental conditions of the composite film deposition and formation and was developed using molecular modeling and simulation tools. The Dreiding 2.21 Force Field was used for the polymer and analyte molecules while graphite parameters were assigned to the carbon black atoms. The polymer considered for this work is methyl vinyl ether / maleic acid copolymer. The target analytes include both inorganic (NH3) and organic (methanol) types of compound. Results indicate different composite-analyte interaction behavior.

  5. Physical properties of immiscible polymers

    NASA Technical Reports Server (NTRS)

    Harris, J. Milton

    1987-01-01

    The demixing of immiscible polymers in low gravity is discussed. Applications of knowledge gained in this research will provide a better understanding of the role of phase segregation in determining the properties of polymer blends made from immiscible polymers. Knowledge will also be gained regarding the purification of biological materials by partitioning between the two liquid phases formed by solution of the polymers polyethylene glycol and dextran in water. Testing of new apparatus for space flight, extension of affinity phase partitioning, refinement of polymer chemistry, and demixing of isopycnic polymer phases in a one gravity environment are discussed.

  6. Jamming of Semiflexible Polymers

    NASA Astrophysics Data System (ADS)

    Hoy, Robert S.

    2017-02-01

    We study jamming in model freely rotating polymers as a function of chain length N and bond angle θ0. The volume fraction at jamming ϕJ(θ0) is minimal for rigid-rodlike chains (θ0=0 ), and increases monotonically with increasing θ0≤π /2 . In contrast to flexible polymers, marginally jammed states of freely rotating polymers are highly hypostatic, even when bond and angle constraints are accounted for. Large-aspect-ratio (small θ0) chains behave comparably to stiff fibers: resistance to large-scale bending plays a major role in their jamming phenomenology. Low-aspect-ratio (large θ0) chains behave more like flexible polymers, but still jam at much lower densities due to the presence of frozen-in three-body correlations corresponding to the fixed bond angles. Long-chain systems jam at lower ϕ and are more hypostatic at jamming than short-chain systems. Implications of these findings for polymer solidification are discussed.

  7. Modelling polymer draft gears

    NASA Astrophysics Data System (ADS)

    Wu, Qing; Yang, Xiangjian; Cole, Colin; Luo, Shihui

    2016-09-01

    This paper developed a new and simple approach to model polymer draft gears. Two types of polymer draft gears were modelled and compared with experimental data. Impact characteristics, in-train characteristics and frequency responses of these polymer draft gears were studied and compared with those of a friction draft gear. The impact simulations show that polymer draft gears can withstand higher impact speeds than the friction draft gear. Longitudinal train dynamics simulations show that polymer draft gears have significantly longer deflections than friction draft gears in normal train operations. The maximum draft gear working velocities are lower than 0.2 m/s, which are significantly lower than the impact velocities during shunting operations. Draft gears' in-train characteristics are similar to their static characteristics but are very different from their impact characteristics; this conclusion has also been reached from frequency response simulations. An analysis of gangway bridge plate failures was also conducted and it was found that they were caused by coupler angling behaviour and long draft gear deflections.

  8. Self reinforcing polymer composites

    SciTech Connect

    Kenig, S.

    1993-12-31

    In the advent of liquid crystalline polymers (LCPs), self reinforcing polymer composites comprising a polymer matrix and an LCP reinforcement, have become a reality. The so called self reinforcement is due to the LCPs orientability characteristics resulting from their rigid molecular backbone and anisotropy structure in the fluid state. Orientation development takes place during melt processing of the LCP composite blends where shear as well as elongational flows occur prior to consolidation to the solid state. By proper flow control anisotropy develops and in-situ composites are obtained. Polymer composites comprising self-reinforcement by LCPs during processing induced flow, were analyzed and studied with respect to their orientation development and resultant mechanical properties. The analysis commenced with the hydrodynamics of immiscible fluids in shear and elongational flows. Based on the analysis, orientation and morphology development in capillary extrusion was studied, using a variety of thermoplastic polymer matrices like amorphous and crystalline polyamides, polycarbonate and polyester in conjunction of a naphthalene based thermotropic LCP. Based on the flow-morphology relationship the amorphous polyamide/LCP composite was further investigated as it exhibited enhanced properties. Laminated composites based on LCP/amorphous polyamide were developed composed of unidirectional extruded and drawn sheets that were subsequently compression molded. Unidirectional, +45/{minus}45 and quasi-isotropic laminates were prepared and analyzed as to their microstructure and mechanical properties.

  9. An electronic nose for amine detection based on polymer/SWNT-COOH nanocomposite.

    PubMed

    Lorwongtragooll, Panida; Wisitsoraat, Anurat; Kerdcharoen, Teerakiat

    2011-12-01

    An electronic nose (e-nose) system based on polymer/carboxylic-functionalized single-walled carbon nanotubes (SWNT-COOH) was developed for sensing various volatile amines. The SWNT-COOH dispersed in the matrix of different polymers; namely, polyvinyl chloride (PVC), cumene terminated polystyrene-co-maleic anhydride (cumene-PSMA), poly(styrenecomaleic acid) partial isobutyl/methyl mixed ester (PSE), and polyvinylpyrrolidon (PVP), were deposited on interdigitated gold electrodes to make the gas sensors. The response of these sensors to volatile amines was studied by both static and dynamic flow measurements. It was found that all sensors exhibited behaviors corresponding to Plateau-Bretano-Stevens law (R2 = 0.81 to 0.99) as the response to volatile amines. Real-world application was demonstrated by applying this e-nose to monitor the odor of sun-dried snakeskin gourami that was pre-processed by salting-preservation. This electronic nose can discriminate sun-dried fish odors with different stored days using a simple pattern recognition based on the principal component analysis (PCA).

  10. Treatment of Osteomyelitis in Rats by Injection of Degradable Polymer Releasing Gentamicin

    PubMed Central

    Brin, Yaron S.; Golenser, Jacob; Mizrahi, Boaz; Maoz, Guy; Domb, Abraham J.; Peddada, Shyamal; Tuvia, Shmuel; Nyska, Abraham; Nyska, Meir

    2009-01-01

    We evaluated the potential of an injectable degradable polymer-Poly(sebacic-co-ricinoleic-ester-anhydride) containing gentamicin for the treatment of osteomyelitis. Osteomyelitis of both tibiae was induced in 13 female Fischer rats by injecting a suspension containing approximately 105 (CFU)/ml of S. Aureus into the tibial medullar canal. Three weeks later both tibiae were X rayed, drilled down the medullar canal, washed with 50µl gentamicin solution (80mg/2ml) and then injected with 50µl P(SARA) + gentamycin 20% w/v to the right tibia and 50µl P(SA-RA) without gentamicin to the left tibia. After an additional 3 weeks, the rats were sacrificed, and radiographs of the tibiae were taken. Histopathological evaluation of the tibiae was done in a blinded manner. X ray radiographs showed that all tibiae developed changes compatible with osteomyelitis in 3 weeks. Histological evaluation revealed significant differences between right and left tibiae in 10 rats. In the left tibia moderate intramedullary abscess formation occurred. In most treated tibiae typical changes included the absence (or minimal grade only) of abscesses. The treated group developed significantly less intramedullary abscesses; the p-value was 0.028. Locally injected degradable polymer releasing gentamicin proved to be efficient histologically in the treatment of osteomyelitis PMID:18692531

  11. Well-Defined Polymers Bearing Pendent Alkene Functionalities via Selective RAFT Polymerization

    PubMed Central

    Ma, Jun; Cheng, Chong; Sun, Guorong; Wooley, Karen L.

    2009-01-01

    A facile synthetic approach for the preparation of well-defined (co)polymers bearing pendent alkene functionalities was established by selective reversible addition-fragmentation chain transfer (RAFT) (co)polymerization. A divinyl monomer 4-(3′-buten-1′-oxy)-2,3,5,6-tetrafluorostyrene (1) with a styrenyl group and a pendent alkene group was synthesized. Due to a very high reactivity of the styrenyl group relative to the alkene group in 1, functional fluoro(co)polymers with both well-defined structures and pendent alkene groups were prepared by RAFT polymerizations of 1 and copolymerization of 1 with pentafluorostyrene (PFS). Alkene-functionalized diblock copolymers were also prepared by RAFT copolymerization of 1 with PFS or styrene, extending from a poly(styrene-alt-maleic anhydride) macro-chain transfer agent. Hydrolysis and ammonolysis of these copolymers resulted in amphiphilic diblock fluorocopolymers with alkene-functionalized hydrophobic segments, which were shown to form internally-functionalized micelles in THF-water. PMID:20640195

  12. Salicylic acid-derived poly(anhydride-ester) electrospun fibers designed for regenerating the peripheral nervous system

    PubMed Central

    Griffin, Jeremy; Delgado-Rivera, Roberto; Meiners, Sally; Uhrich, Kathryn E.

    2011-01-01

    Continuous biomaterial advances and the regenerating potential of the adult human peripheral nervous system offer great promise for restoring full function to innervated tissue following traumatic injury via synthetic nerve guidance conduits. To most effectively facilitate nerve regeneration, a tissue engineering scaffold within a conduit must be similar to the linear microenvironment of the healthy nerve. To mimic the native nerve structure, aligned poly(lactic-co-glycolic acid)/bioactive polyanhydride fibrous substrates were fabricated through optimized electrospinning parameters with diameters of 600 ± 200 nm. Scanning electron microscopy images show fibers with a high degree of alignment. Schwann cells and dissociated rat dorsal root ganglia demonstrated elongated and healthy proliferation in a direction parallel to orientated electrospun fibers with significantly longer Schwann cell process length and neurite outgrowth when compared to randomly orientated fibers. Results suggest that an aligned polyanhydride fiber mat holds tremendous promise as a supplement scaffold for the interior of a degradable polymer nerve guidance conduit. Bioactive salicylic acid based polyanhydride fibers are not limited to nerve regeneration and offer exciting promise for a wide variety of biomedical applications. PMID:21442724

  13. Applying Uniform Polymer Coatings To Microspheres

    NASA Technical Reports Server (NTRS)

    Lee, M. C.

    1985-01-01

    Acoustic levitation yields even coating on glass microsphres. Automatic Coating Apparatus injects polymer into acoustic levitator, moves glass sphere into polymer, dries polymer, and removes coated sphere. Apparatus injects more polymer for coating another sphere, and cycle repeats.

  14. Effect of polymer-polymer interactions on the surface tension of colloid-polymer mixtures

    NASA Astrophysics Data System (ADS)

    Moncho-Jordá, A.; Rotenberg, B.; Louis, A. A.

    2003-12-01

    The density profile and surface tension for the interface of phase-separated colloid-polymer mixtures have been studied in the framework of the square gradient approximation for both ideal and interacting polymers in good solvent. The calculations show that in the presence of polymer-polymer excluded volume interactions the interfaces have lower widths and surface tensions compared to the case of ideal polymers. These results are a direct consequence of the shorter range and smaller depth of the depletion potential between colloidal particles induced by interacting polymers.

  15. Antithrombogenic Polymer Coating.

    DOEpatents

    Huang, Zhi Heng; McDonald, William F.; Wright, Stacy C.; Taylor, Andrew C.

    2003-01-21

    An article having a non-thrombogenic surface and a process for making the article are disclosed. The article is formed by (i) coating a polymeric substrate with a crosslinked chemical combination of a polymer having at least two amino substituted side chains, a crosslinking agent containing at least two crosslinking functional groups which react with amino groups on the polymer, and a linking agent containing a first functional group which reacts with a third functional group of the crosslinking agent, and (ii) contacting the coating on the substrate with an antithrombogenic agent which covalently bonds to a second functional group of the linking agent. In one example embodiment, the polymer is a polyamide having amino substituted alkyl chains on one side of the polyamide backbone, the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl, the linking agent is a polyhydrazide and the antithrombogenic agent is heparin.

  16. Atomic Oxygen Textured Polymers

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Hunt, Jason D.; Drobotij, Erin; Cales, Michael R.; Cantrell, Gidget

    1995-01-01

    Atomic oxygen can be used to microscopically alter the surface morphology of polymeric materials in space or in ground laboratory facilities. For polymeric materials whose sole oxidation products are volatile species, directed atomic oxygen reactions produce surfaces of microscopic cones. However, isotropic atomic oxygen exposure results in polymer surfaces covered with lower aspect ratio sharp-edged craters. Isotropic atomic oxygen plasma exposure of polymers typically causes a significant decrease in water contact angle as well as altered coefficient of static friction. Such surface alterations may be of benefit for industrial and biomedical applications. The results of atomic oxygen plasma exposure of thirty-three (33) different polymers are presented, including typical morphology changes, effects on water contact angle, and coefficient of static friction.

  17. Liquid crystalline polymers

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The remarkable mechanical properties and thermal stability of fibers fabricated from liquid crystalline polymers (LCPs) have led to the use of these materials in structural applications where weight savings are critical. Advances in processing of LCPs could permit the incorporation of these polymers into other than uniaxial designs and extend their utility into new areas such as nonlinear optical devices. However, the unique feature of LCPs (intrinsic orientation order) is itself problematic, and current understanding of processing with control of orientation falls short of allowing manipulation of macroscopic orientation (except for the case of uniaxial fibers). The current and desirable characteristics of LCPs are reviewed and specific problems are identified along with issues that must be addressed so that advances in the use of these unique polymers can be expedited.

  18. Doped Chiral Polymer Metamaterials

    NASA Technical Reports Server (NTRS)

    Park, Cheol (Inventor); Kang, Jin Ho (Inventor); Gordon, Keith L. (Inventor); Sauti, Godfrey (Inventor); Lowther, Sharon E. (Inventor); Bryant, Robert G. (Inventor)

    2017-01-01

    Some implementations provide a composite material that includes a first material and a second material. In some implementations, the composite material is a metamaterial. The first material includes a chiral polymer (e.g., crystalline chiral helical polymer, poly-.gamma.-benzyl-L-glutamate (PBLG), poly-L-lactic acid (PLA), polypeptide, and/or polyacetylene). The second material is within the chiral polymer. The first material and the second material are configured to provide an effective index of refraction value for the composite material of 1 or less. In some implementations, the effective index of refraction value for the composite material is negative. In some implementations, the effective index of refraction value for the composite material of 1 or less is at least in a wavelength of one of at least a visible spectrum, an infrared spectrum, a microwave spectrum, and/or an ultraviolet spectrum.

  19. Inorganic polymer engineering materials

    SciTech Connect

    Stone, M.L.

    1993-06-01

    Phosphazene-based, inorganic-polymer composites have been produced and evaluated as potential engineering materials. The thermal, chemical, and mechanical properties of several different composites made from one polymer formulation have been measured. Measured properties are very good, and the composites show excellent promise for structural applications in harsh environments. Chopped fiberglass, mineral, cellulose, and woodflour filled composites were tested. Chopped fiberglass filled composites showed the best overall properties. The phosphazene composites are very hard and rigid. They have low dielectric constants and typical linear thermal expansion coefficients for polymers. In most cases, the phosphazene materials performed as well or better than analogous, commercially available, filled phenolic composites. After 3 to 5 weeks of exposure, both the phosphazene and phenolics were degraded to aqueous bases and acids. The glass filled phosphazene samples were least affected.

  20. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1992-01-01

    Progress was made in several areas on the preparation of carbon fiber composites using advanced polymer resins. Polymer infiltration studies dealt with ways of preparing composite materials from advanced polymer resins and carbon fibers. This effort is comprised of an integrated approach to the process of composite part fabrication. The goal is to produce advanced composite materials for automated part fabrication using textile and robotics technology in the manufacture of subsonic and supersonic aircraft. The object is achieved through investigations at the NASA Langley Research Center and by stimulating technology transfer between contract researchers and the aircraft industry. Covered here are literature reviews, a status report on individual projects, current and planned research, publications, and scheduled technical presentations.

  1. A fundamental understanding of the effects of polymer microstructure and polymer-drug interactions on in vitro drug release kinetics in bioerodible polyanhydrides

    NASA Astrophysics Data System (ADS)

    Shen, Elizabeth Elin

    This research aims to create an experimental and theoretical framework to investigate the effects of polymer microstructure on controlled drug delivery from bioerodible polyanhydride copolymers of poly(l,6-bis-p-carboxyphenoxy hexane-co-sebacic anhydride) (CPH:SA). The central hypothesis is that microphase separation is driven by both copolymer composition and difference in hydrophobicity of the two monomers, and drugs will thermodynamically partition into the phase-separated micro-domains. Four specific areas were investigated to fulfill the overall objective: microstructural characterization; in vitro release kinetics; mathematical modeling; and microsphere fabrication. Several characterization methods (DSC, WAXD, SAXS, AFM, 1NMR) were used to study polyanhydride microstructure, and showed that both 20:80 and 80:20 CPH:SA copolymers exhibit microphase separation driven by differences in hydrophobicity and tend toward a "block-like" microstructure. The model drugs p-nitroaniline (PNA), disperse yellow 3 (DY), and brilliant blue (BB) were found to thermodynamically partition into the micro-domains according to compatibility with the phases in the microphase-separated copolymers. The kinetics of in vitro monomer and drug release revealed that for homogeneous polymers, excellent correlation between polymer degradation and drug release was observed for both PNA and DY. In heterogeneous copolymers, a burst effect was observed when incompatible drugs were loaded into the microphase-separated polymer. Based on these results, the following mechanism was proposed: A drug molecule, when loaded into a polymer, will distribute itself into compatible regions (based on the relative hydrophobicity) until saturation is reached; excess drug will disperse itself into less compatible regions, resulting in a pronounced burst effect. A mathematical model was developed to describe drug and monomer release from the microphase-separated copolymers. The model hypothesizes that the erosion

  2. Fabrication of enzyme reactor utilizing magnetic porous polymer membrane for screening D-Amino acid oxidase inhibitors.

    PubMed

    Jiang, Jun Fang; Qiao, Juan; Mu, Xiao Yu; Moon, Myeong Hee; Qi, Li

    2017-04-01

    In this work, a unique D-amino acid oxidase reactor for enhanced enzymolysis efficiency is presented. A kind of magnetic polymer matrices, composed of iron oxide nanoparticles and porous polymer membrane (poly styrene-co-maleic anhydride), was prepared. With covalent bonding D-Amino acid oxidase on the surface of the matrices and characterization of scanning electron microscope and vibrating sample magnetometer, it demonstrated that the membrane enzyme reactor was successfully constructed. The enzymolysis efficiency of the enzyme reactor was evaluated and the apparent Michaelis-Menten constants of D-Amino acid oxidase were determined (Km was 1.10mM, Vmax was 23.8mMmin(-1)) by a chiral ligand exchange capillary electrophoresis protocol with methionine as the substrate. The results indicated that the enzyme reactor could exhibit good stability and excellent reusability. Importantly, because the enzyme and the substrate could be confined into the pores of the matrices, the enzyme reactor displayed the improved enzymolysis efficiency due to the confinement effect. Further, the prepared enzyme reactor was applied for D-Amino acid oxidase inhibitors screening. It has displayed that the proposed protocol could pave a new way for fabrication of novel porous polymer membrane based enzyme reactors to screen enzyme inhibitors.

  3. Influence of Temperature on the Colloidal Stability of Polymer-Coated Gold Nanoparticles in Cell Culture Media.

    PubMed

    Zyuzin, Mikhail V; Honold, Tobias; Carregal-Romero, Susana; Kantner, Karsten; Karg, Matthias; Parak, Wolfgang J

    2016-04-06

    The temperature-dependence of the hydrodynamic diameter and colloidal stability of gold-polymer core-shell particles with temperature-sensitive (poly(N-isopropylacrylamide)) and temperature-insensitive shells (polyallylaminine hydrochloride/polystyrensulfonate, poly(isobutylene-alt-maleic anhydride)-graft-dodecyl) are investigated in various aqueous media. The data demonstrate that for all nanoparticle agglomeration, i.e., increase in effective nanoparticle size, the presence of salts or proteins in the dispersion media has to be taken into account. Poly(N-isopropylacrylamide) coated nanoparticles show a reversible temperature-dependent increase in size above the volume phase transition of the polymer shell when they are dispersed in phosphate buffered saline or in media containing protein. In contrast, the nanoparticles coated with temperature-insensitive polymers show a time-dependent increase in size in phosphate buffered saline or in medium containing protein. This is due to time-dependent agglomeration, which is particularly strong in phosphate buffered saline, and induces a time-dependent, irreversible increase in the hydrodynamic diameter of the nanoparticles. This demonstrates that one has to distinguish between temperature- and time-induced agglomerations. Since the size of nanoparticles regulates their uptake by cells, temperature-dependent uptake of thermosensitive and non-thermosensitive nanoparticles by cells lines is compared. No temperature-specific difference between both types of nanoparticles could be observed.

  4. Composite solid polymer electrolyte membranes

    DOEpatents

    Formato, Richard M.; Kovar, Robert F.; Osenar, Paul; Landrau, Nelson; Rubin, Leslie S.

    2001-06-19

    The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

  5. An overview of degradable polymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many degradable polymers are being investigated for research purpose or for possible commercial use. This overview provides a listing of the more important degradable polymers and their mechanisms of action. Some application areas, particularly in packaging, housewares, personal care, biomaterials, ...

  6. An overview of degradable polymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many degradable polymers are being investigated for research purpose or for possible commercial use. This overview provides a listing of the more important degradable polymers and their mechanisms of action. Some application areas, particularly in packaging, housewares, personal care, biomaterials...

  7. Polymer Chemistry in High School.

    ERIC Educational Resources Information Center

    Stucki, Roger

    1984-01-01

    Discusses why polymer chemistry should be added to the general chemistry curriculum and what topics are appropriate (listing traditional with related polymer topics). Also discusses when and how these topics should be taught. (JN)

  8. Classroom Demonstrations of Polymer Principles.

    ERIC Educational Resources Information Center

    Rodriguez, F.

    1990-01-01

    Classroom demonstrations of selected mechanical properties of polymers are described that can be used to make quantitative measurements. Stiffness, strength, and extensibility are mechanical properties used to distinguish one polymer from another. (KR)

  9. Stretched polymer nanohairs by nanodrawing.

    PubMed

    Jeong, Hoon Eui; Lee, Sung Hoon; Kim, Pilnam; Suh, Kahp Y

    2006-07-01

    A simple, yet innovative, method is presented for fabricating high-aspect-ratio polymer nanohairs (aspect ratio >20) on a solid substrate by sequential application of molding and drawing of a thin polymer film. The polymer film was prepared by spin coating on a rigid or flexible substrate, and the temperature was raised above the polymer's glass transition while in conformal contact with a poly(urethane acrylate) mold having nanocavities. Consequently, capillary forces induced deformation of the polymer melt into the void spaces of the mold and the filled nanostructure was further elongated upon removal of the mold due to tailored adhesive force at the mold/polymer interface. The optimum value of the work of adhesion at the mold/polymer interface ranged from 0.9 to 1.1 times that at the substrate/polymer interface.

  10. Composite solid polymer electrolyte membranes

    DOEpatents

    Formato, Richard M.; Kovar, Robert F.; Osenar, Paul; Landrau, Nelson; Rubin, Leslie S.

    2006-05-30

    The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

  11. A Course in Polymer Processing.

    ERIC Educational Resources Information Center

    Soong, David S.

    1985-01-01

    A special-topics course in polymer processing has acquired regular course status. Course goals, content (including such new topics as polymer applications in microelectronics), and selected term projects are described. (JN)

  12. Inorganic and Organometallic Polymers

    NASA Astrophysics Data System (ADS)

    Chandrasekhar, Vadapalli

    This textbook is intended to give an understanding of the basic principles that constitute the field of non-conventional polymers containing inorganic and organometalic units as the repeating units. Each chapter will be self-explanatory with a good background so that it can be easily understood at the senior undergraduate level. The principles involved in the preparation of these polymers, their characterisation and their applications will be discussed. Basic inorganic chemistry required for the understanding of each topic is presented so that the content of the chapter is readily understood.

  13. Computer modeling of polymers

    NASA Technical Reports Server (NTRS)

    Green, Terry J.

    1988-01-01

    A Polymer Molecular Analysis Display System (p-MADS) was developed for computer modeling of polymers. This method of modeling allows for the theoretical calculation of molecular properties such as equilibrium geometries, conformational energies, heats of formations, crystal packing arrangements, and other properties. Furthermore, p-MADS has the following capabilities: constructing molecules from internal coordinates (bonds length, angles, and dihedral angles), Cartesian coordinates (such as X-ray structures), or from stick drawings; manipulating molecules using graphics and making hard copy representation of the molecules on a graphics printer; and performing geometry optimization calculations on molecules using the methods of molecular mechanics or molecular orbital theory.

  14. Trifluoromethyl-substituted polymers

    NASA Technical Reports Server (NTRS)

    Cassidy, Patrick E.

    1990-01-01

    The synthesis of polymers is discussed. It includes: (1) the synthesis of fluorine-containing crosslinked poly(ether ketones); (2) the synthesis and characterization of poly(imide amides) and their N-methylated analogues; (3) the synthesis of fluorine-containing aromatic polyethers; (4) the synthesis of novel fluorine-containing aromatic polysiloxanes; and (5) the conversion of 6F-containing polythioethers to polysulfones. It is hoped that these polymers will find use as low dielectric materials in electronic applications, function as thermal control coatings, or be suitable elastomeric sealants for extreme service conditions.

  15. Randomly Hyperbranched Polymers

    NASA Astrophysics Data System (ADS)

    Konkolewicz, Dominik; Gilbert, Robert G.; Gray-Weale, Angus

    2007-06-01

    We describe a model for the structures of randomly hyperbranched polymers in solution, and find a logarithmic growth of radius with polymer mass. We include segmental overcrowding, which puts an upper limit on the density. The model is tested against simulations, against data on amylopectin, a major component of starch, on glycogen, and on polyglycerols. For samples of synthetic polyglycerol and glycogen, our model holds well for all the available data. The model reveals higher-level scaling structure in glycogen, related to the β particles seen in electron microscopy.

  16. Radiation ageing of polymers

    NASA Astrophysics Data System (ADS)

    Bartoníček, B.; Hnát, V.; Plaček, V.

    1999-01-01

    Radiation effects on polymers in the presence of air are characterized by dose rate effects and at enhanced temperature by synergistic effects of temperature and radiation. For a reliable simulation of long-term ageing of polymers, conditions for the homogeneous radiooxidation have to be reached. The dose rate values, at which the homogeneous oxidation of irradiated EPR/EVA plates of various thicknesses occurs throughout the sample interior, have been determined. The methodology for the lifetime assessment of cable polymeric materials on the base of the oxidation induction time determination is described.

  17. Photoluminescent conductor polymer holograms

    NASA Astrophysics Data System (ADS)

    Ruiz-Limón, B.; Olivares-Pérez, A.; Ponce-Lee, E. L.; Hernández-Garay, M. P.; Páez-Trujillo, G.; Fuentes-Tapia, I.

    2007-02-01

    An organic conductor polymer was doped with benzalkonium chloride to get a photoluminescent effect at 560 nm and it was used as holographic material. We used a digital image to generate a hologram in a computer and it was transferred by microlithography techniques to our polymer to get a phase hologram. The transference is successful by rubbing, the heat increment produce temperature gradients and the information in the mask is transferred to the material by the refraction index changes, thus the film is recorded. We recorded some gratings to observe the behavior of photoluminescent light with different frequencies when it is radiated with a green laser beam at 532 nm.

  18. Processable Electronically Conducting Polymers

    DTIC Science & Technology

    1991-01-01

    is also evident in the electronic spectra of the polymer as the (CH)x formed in this manner has a band gap (absorption onset) at -1.9 eV (650 nm) and...an absorption maximum at 2.8 eV (440 nm) (compared to a band gap of 1.4 eV (885 nm) for Shirakawa (CH)x). As is the case with Durham (CH)x, orientation...annulated ring system locks the polymer into a stable conformation, and thus the optical band gaps of the mono- and disubstituted species are at

  19. Antibacterial polymer coatings.

    SciTech Connect

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  20. Randomly hyperbranched polymers.

    PubMed

    Konkolewicz, Dominik; Gilbert, Robert G; Gray-Weale, Angus

    2007-06-08

    We describe a model for the structures of randomly hyperbranched polymers in solution, and find a logarithmic growth of radius with polymer mass. We include segmental overcrowding, which puts an upper limit on the density. The model is tested against simulations, against data on amylopectin, a major component of starch, on glycogen, and on polyglycerols. For samples of synthetic polyglycerol and glycogen, our model holds well for all the available data. The model reveals higher-level scaling structure in glycogen, related to the beta particles seen in electron microscopy.

  1. Nanoparticles from renewable polymers

    PubMed Central

    Wurm, Frederik R.; Weiss, Clemens K.

    2014-01-01

    The use of polymers from natural resources can bring many benefits for novel polymeric nanoparticle systems. Such polymers have a variety of beneficial properties such as biodegradability and biocompatibility, they are readily available on large scale and at low cost. As the amount of fossil fuels decrease, their application becomes more interesting even if characterization is in many cases more challenging due to structural complexity, either by broad distribution of their molecular weights (polysaccharides, polyesters, lignin) or by complex structure (proteins, lignin). This review summarizes different sources and methods for the preparation of biopolymer-based nanoparticle systems for various applications. PMID:25101259

  2. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1991-01-01

    Progress was made on the preparation of carbon fiber composites using advanced polymer resins. Processes reported include powder towpreg process, weaving towpreg made from dry powder prepreg, composite from powder coated towpreg, and toughening of polyimide resin (PMR) composites by semi-interpenetrating networks. Several important areas of polymer infiltration into fiber bundles will be researched. Preparation to towpreg for textile preform weaving and braiding and for automated tow placement is a major goal, as are the continued development of prepregging technology and the various aspects of composite part fabrication.

  3. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1995-01-01

    Polymer infiltration investigations were directed toward development of methods by which to produce advanced composite material for automated part fabrication utilizing textile and robotic technology in the manufacture of subsonic and supersonic aircraft. Significant progress was made during the project on the preparation of carbon fiber composites using advanced polymer resins. The findings and results of the project are summarized in the attached paper entitled 'Powder-Coated Towpreg: Avenues to Near Net Shape Fabrication of High Performance Composite.' Also attached to this report is the second of two patent applications submitted as a result of these studies.

  4. Shape memory polymer medical device

    DOEpatents

    Maitland, Duncan; Benett, William J.; Bearinger, Jane P.; Wilson, Thomas S.; Small, IV, Ward; Schumann, Daniel L.; Jensen, Wayne A.; Ortega, Jason M.; Marion, III, John E.; Loge, Jeffrey M.

    2010-06-29

    A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

  5. Covalent polymer-drug conjugates.

    PubMed

    Elvira, Carlos; Gallardo, Alberto; Roman, Julio San; Cifuentes, Alejandro

    2005-01-31

    In this work, polymer-drugs conjugates used as drug delivery systems (DDS) are revised attending to their chemical conjugation. Namely, the classification of this type of DDS is based on the conjugation sites of the reactive groups (i.e., via end groups or pendant polymer groups). Advantages and limitations of these types of DDS are discussed through representative examples of polymer-drugs and polymer-proteins conjugates recently developed.

  6. Graphene-Based Polymer Nanocomposites

    DTIC Science & Technology

    2015-03-31

    polymerize in-situ around the fillers or even graft to them [71], thus it overcomes the problem of dramatically increased viscosity of the polymer ... polymerization is also applicable for a variety of polymers [71]. It is particularly useful for some insoluble and thermally-unstable polymers such as...Specific polymers In-situ Polymerization • High filler concentration • Strong interfaces • Only in solvent Melt Blending • Economic and convenient

  7. Aerogel/polymer composite materials

    NASA Technical Reports Server (NTRS)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2010-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  8. Synthesis of thermally stable polymers

    NASA Technical Reports Server (NTRS)

    Butler, G. B.

    1978-01-01

    The reaction of bis triazo linediones with divinyl esters and substituted styrenes was investigated. Twenty new polymers were derived via reaction of two previously synthesized bis triazol linediones and four new bis atriazol linediones with eight styrenes. The structure and polymer properties of these thermally stable polymers was examined. The reaction of triazo linediones with enol esters was also considered.

  9. Synthesis of 2,3-dihydroquinazolin-4(1H)-ones by three-component coupling of isatoic anhydride, amines, and aldehydes catalyzed by magnetic Fe(3)O(4) nanoparticles in water.

    PubMed

    Zhang, Zhan-Hui; Lü, Hong-Yan; Yang, Shu-Hong; Gao, Jian-Wu

    2010-09-13

    A simple and efficient protocol for one-pot three-component coupling of isatoic anhydride, amines, and aldehydes in water using magnetically recoverable Fe(3)O(4) nanoparticles is reported. This methodology results in the synthesis of a variety of 2,3-dihydroquinazolin-4(1H)-ones in high yields. The catalyst can be recovered and recycled without a significant loss in the catalytic activity.

  10. The variation characteristics analysis of polymer concentration in polymer flooding

    NASA Astrophysics Data System (ADS)

    Li, Kai

    2017-03-01

    Since the polymer industry promotion block production, with the development of polymer flooding from the main oil layer to the second type of oil gradually expanded, polymer flooding the whole process of the development of the law is also gradually deepening, gathering concentration is the analysis of polymer. The results show that there is a certain variation rule of the concentration of polymer in the whole process of polymer flooding development through the accumulation of a large number of gathering concentration data. In this paper, the characteristics of polymer flooding concentration, comprehensive water cut down rate, comprehensive water cut down, water cutoff duration and subsequent water flooding concentration and comprehensive water content are expounded, as well as the influence of polymer concentration and the changing trend of the concentration of polymer flooding in the development process was analyzed. In-depth study and grasp the concentration of mining concentration, can further improve the overall effect of polymer flooding development, but also for the follow-up injection block, especially the second type of polymer flooding development has great significance.

  11. Mesoporous carbons and polymers

    DOEpatents

    Bell, William; Dietz, Steven

    2001-01-01

    A mesoporous material prepared by polymerizing a resorcinol/formaldehyde system from an aqueous solution containing resorcinol, formaldehyde and a surfactant and optionally pyrolyzing the polymer to form a primarily carbonaceous solid. The material has an average pore size between 4 and 75 nm and is suitable for use in liquid-phase surface limited applications, including sorbent, catalytic, and electrical applications.

  12. Rippling of polymer nanofibers.

    PubMed

    Wu, Xiang-Fa; Kostogorova-Beller, Yulia Y; Goponenko, Alexander V; Hou, Haoqing; Dzenis, Yuris A

    2008-12-01

    This paper studies the evolution mechanism of surface rippling in polymer nanofibers under axial stretching. This rippling phenomenon has been detected in as-electrospun polyacrylonitrile in recent single-fiber tension tests, and in electrospun polyimide nanofibers after imidization. We herein propose a one-dimensional nonlinear elastic model that takes into account the combined effect of surface tension and nonlinear elasticity during the rippling initiation and its evolution in compliant polymer nanofibers. The polymer nanofiber is modeled as an incompressible, isotropically hyperelastic Mooney-Rivlin solid. The fiber geometry prior to rippling is considered as a long circular cylinder. The governing equation of surface rippling is established through linear perturbation of the static equilibrium state of the nanofiber subjected to finite axial prestretching. The critical stretch and ripple wavelength are determined in terms of surface tension, elastic property, and fiber radius. Numerical examples are demonstrated to examine these dependencies. In addition, a critical fiber radius is determined, below which the polymer nanofibers are intrinsically unstable. The present model, therefore, is capable of predicting the rippling condition in compliant nanofibers, and can be further used as a continuum mechanics approach for the study of surface instability and nonlinear wave propagation in compliant fibers and wires at the nanoscale.

  13. High temperature polymer concrete

    DOEpatents

    Fontana, J.J.; Reams, W.

    1984-05-29

    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.

  14. Cyclic polymers from alkynes

    NASA Astrophysics Data System (ADS)

    Roland, Christopher D.; Li, Hong; Abboud, Khalil A.; Wagener, Kenneth B.; Veige, Adam S.

    2016-08-01

    Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer.

  15. Solid polymer electrolyte compositions

    DOEpatents

    Garbe, James E.; Atanasoski, Radoslav; Hamrock, Steven J.; Le, Dinh Ba

    2001-01-01

    An electrolyte composition is featured that includes a solid, ionically conductive polymer, organically modified oxide particles that include organic groups covalently bonded to the oxide particles, and an alkali metal salt. The electrolyte composition is free of lithiated zeolite. The invention also features cells that incorporate the electrolyte composition.

  16. Durable metallized polymer mirror

    DOEpatents

    Schissel, Paul O.; Kennedy, Cheryl E.; Jorgensen, Gary J.; Shinton, Yvonne D.; Goggin, Rita M.

    1994-01-01

    A metallized polymer mirror construction having improved durability against delamination and tunneling, comprising: an outer layer of polymeric material; a metal oxide layer underlying the outer layer of polymeric material; a silver reflective layer underneath the metal oxide layer; and a layer of adhesive attaching the silver layer to a substrate.

  17. Durable metallized polymer mirror

    DOEpatents

    Schissel, P.O.; Kennedy, C.E.; Jorgensen, G.J.; Shinton, Y.D.; Goggin, R.M.

    1994-11-01

    A metallized polymer mirror construction is disclosed having improved durability against delamination and tunneling, comprising: an outer layer of polymeric material; a metal oxide layer underlying the outer layer of polymeric material; a silver reflective layer underneath the metal oxide layer; and a layer of adhesive attaching the silver layer to a substrate. 6 figs.

  18. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1992-01-01

    The preparation is reported of carbon fiber composites using advanced polymer resins. Current and ongoing research activities include: powder towpreg process; weaving, braiding and stitching dry powder prepreg; advanced tow placement; and customized ATP towpreg. The goal of these studies is to produce advanced composite materials for automated part fabrication using textile and robotics technology in the manufacture of subsonic and supersonic aircraft.

  19. Conducting Polymers for Neutron Detection

    SciTech Connect

    Kimblin, Clare; Miller, Kirk; Vogel, Bob; Quam, Bill; McHugh, Harry; Anthony, Glen; Mike, Grover

    2007-12-01

    Conjugated polymers have emerged as an attractive technology for large-area electronic applications. As organic semiconductors, they can be used to make large-area arrays of diodes or transistors using fabrication techniques developed for polymer coatings, such as spraying and screen-printing. We have demonstrated both neutron and alpha detection using diodes made from conjugated polymers and have done preliminary work to integrate a boron carbide layer into the conventional polymer device structure to capture thermal neutrons. The polymer devices appear to be insensitive to gamma rays, due to their small physical thickness and low atomic number.

  20. Gel polymer electrolytes for batteries

    DOEpatents

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.