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Modified Polymer (modified + polymer)
Selected AbstractsFunctional modification of poly(vinyl alcohol) through phosphorus containing nitrogen heterocyclic moietiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008S. Karpagam Abstract Functional modification of poly(vinyl alcohol) (PVA) with phosphorus containing nitrogen heterocyclic has been believed to have extensive thermal and biological applications in the area of polymers. Efforts have been taken for the synthesis of phosphorus-containing N -heterocyclic (5,6 member and fused ring) based PVA. The synthesized compounds were characterized using UV, FTIR, and NMR spectral studies. Thermal studies (DSC-TGA) scans display phosphorus-containing five membered and fused heterocyclic-based PVA has less thermal stability than six-membered compounds. Modified polymers infer to have excellent bacterial response against micro-organisms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Macrocyclic polyamine-modified poly(glycidyl methacrylate- co -ethylene dimethacrylate) monolith for capillary electrochromatographyELECTROPHORESIS, Issue 11 2008Yun Tian Abstract 1,4,10,13,16-Pentaazatricycloheneicosane-9,17-dione (macrocyclic polyamine)-modified polymer-based monolithic column for CEC was prepared by ring opening reaction of epoxide groups from poly(glycidyl methacrylate- co -ethylene dimethacrylate) (GMA- co -EDMA) monolith with macrocyclic polyamine. Conditions such as reaction time and concentration of macrocyclic polyamine for the modification reaction were optimized to generate substantial EOF and enough chromatographic interactions. Anodic EOF was observed in the pH range of 2.0,8.0 studied due to the protonation of macrcyclic polyamine at the surface of the monolith. Morphology of the monolithic column was examined by SEM and the incorporation of macrocyclic polyamine to the poly(GMA- co -EDMA) monolith was characterized by infrared (IR) spectra. Successful separation of inorganic anions, isomeric benzenediols, and benzoic acid derivatives on the monolithic column was achieved for CEC. In addition to hydrophobic interaction, hydrogen bonding and electrostatic interaction played a significant role in the separation process. [source] Use of N -(N,-arylamino)maleimides to improve the thermal properties of poly(vinyl chloride) through chemical modification and graft copolymerizationJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2008Abir S. Abdel-Naby The reaction of poly(vinyl chloride) (PVC) with N -(N,-arylamino)maleimide derivatives was studied. The thermal stability of the modified polymer was improved markedly when compared with that of the unmodified polymer. The stability improvement was attributed to the replacement of the labile chlorine atoms by more stable organic groups. The modified polymer also showed a lower extent of discoloration when compared with that of unmodified PVC. In order to introduce a polymeric stabilizer into PVC, the dienophilic monomer was chemically grafted onto the polymeric chains. The mechanism of the chemical modification as well as that of the graft copolymerization are discussed. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Preparation and characterization of pore wall-functionalized three-dimensionally ordered macroporous syndiotactic polystyrenePOLYMER ENGINEERING & SCIENCE, Issue 2 2009Xu Zhang A versatile method for the modification of three-dimensionally ordered macroporous (3DOM) highly syndiotactic polystyrene via chloromethylation at the pore walls has been demonstrated. This was followed by reaction with dimethylamine to establish a versatile approach to functionalization of such macroporous polymers. High syndiotacticity of 3DOM sPS is necessary for maintenance of the morphology of the original ordered pore structure after chloromethylation. The relative content of chloromethyl groups was shown to be 1.89 mmol/g3DOM sPS by TG-titration. The functionalized 3DOM sPS was characterized by SEM, FT-IR, and DSC to demonstrate that chloromethylation had occurred at the pore walls and that the dimethylamino moiety had replaced the chlorine atom of the chloromethyl group. DSC examination of the modified polymer indicated that the crystallinity of 3DOM sPS is little affected by functionalization. Thus the excellent properties of sPS are retained by the functionalized material. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers [source] Synthesis and Characterization of p -[Perfluoro-1-(2-fluorosulfonylethoxy)] ethylated PolystyreneCHINESE JOURNAL OF CHEMISTRY, Issue 4 2003Guan Chuan-Jin Abstract A new fluorinated polystyrene bearing a p -substituted perfluoro[1-(2-fluorosulfonylethoxy)] ethyl group was synthesized via one-electron oxidation of polystyrene by perfluoro [2-(2-fluorosulfonylethoxy)] propionyl peroxide at different peroxide to polystyrene molar ratios. The yield of perfluoroalkylation decreases with the increase of the reactant molar ratio. The modified polymer has been characterized by various techniques: the ring perfluoro[l-(2-fluorosulfonylethoxy)] ethylation has been proved by FT-IR and 19F NMR; the X-ray photoelectron spectra (XPS) show the maximum binding energy of Fls, Ols Cls(two kinds of carbon atoms, namely C-H and C-F) and S2p, respectively; desulfonylation of the fluorinated polystyrene appearing at 217 °C has been found by its thermogravimetric analysis (TGA). The determinations of contact angle, refractive index and glass transition temperature of the modified polymer have disclosed that when the contact angle increases with the increase of the molar ratio, the refractive index and glass transition temperature decrease. The polydispersity values indicate that the degradation of the polymer chains did not occur during the reaction. [source] Pt-catalyzed chemical modification of ,,,-bis(hydrido)polydimethylsiloxanes and copoly(methylhydridosiloxane/dimethylsiloxane) with vinylheptaphenylcyclotetrasiloxaneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2005Thomas M. Gädda Abstract Pt-catalyzed hydrosilylation between vinylheptaphenylcyclotetrasiloxane and a series of ,,,-bis(hydrido)polydimethylsiloxanes and copoly(methylhydridosiloxane/dimethylsiloxane) was used to prepare chemically modified materials. These modified polymers were characterized by IR, UV, and 1H, 13C, and 29Si NMR spectroscopy and gel permeation chromatography (GPC). The molecular weights, determined by GPC, UV, and NMR end-group analysis, showed the anticipated increases. The thermal properties of the polymers were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The crystallinity, determined by DSC, was either reduced or completely eliminated for the modified polymers. The thermal stabilities, measured in both air and nitrogen by TGA, were slightly higher than the thermal stability of ,,,-bis(trimethylsiloxy)polydimethylsiloxane. Significantly increased bulk viscosities were observed for all the modified polymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3007-3017, 2005 [source] The effect of long chain branching on the processability of polypropylene in thermoformingPOLYMER ENGINEERING & SCIENCE, Issue 5 2004A. D. Gotsis Linear polypropylene was modified by reaction with peroxydicarbonates in a twin screw extruder to obtain varied degrees of long chain branching. The melt strength and the elasticity of the modified polymers were found to increase with the modification. The processability in foaming and thermoforming processes improved with branching and showed an optimum, beyond which higher degrees of long chain branching appeared not to help any further. The branched PP samples showed distinct strain hardening in the elongational viscosity, which was absent from the original linear melts. Melt strength, elasticity and strain hardening increased with the increase of the number of long chain branches on the main chain. The effect of molecular weight and molecular weight distribution of the precursor on the improvement of the processability of the polymer was examined. Polym. Eng. Sci. 44:973,982, 2004. © 2004 Society of Plastics Engineers. [source] Hydrophobically modified polyelectrolytes II: synthesis and characterization of poly(acrylic acid-co-alkyl acrylate)POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11-12 2001Dong-qing Zhuang Abstract A series of hydrophobically modified poly(acrylic acid)(RH -PAA) were synthesized by solution copolymerization of acrylic acid with a small amount of alkyl acrylate (alkyl chain with a length of 8, 12, 14, 16, 18) and their solution properties were also systematically studied. It was found that the random distribution of alkyl acrylate along the polymeric backbone imparts these new materials pronounced associating ability in aqueous solution and the associating abilities vary with the chain length of the hydrophobic groups. In dilute solution, intramolecular association is observed from the intrinsic viscosity and the dependence of the intrinsic viscosity on chain length and ionic strength is also discussed. In semiconcentration solution, the modified polymers exhibit viscosities of several orders of magnitude higher than the unmodified poly(sodium acrylate) due to the strong intermolecular hydrophobic association. And the viscosifying effects become more significant with the increasing length of the alkyl chain. The copolymer solutions are highly pseudoplastic. Evidences for the hydrophobically associating interaction between hydrocarbon groups are provided by the dependence of the Brookfield viscosity on concentration, temperature, shear rate, ionic strength and pH. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||