01692nas a2200229 4500008004100000022001400041245014700055210006900202260006800271300001400339490000700353520082000360653002101180653002501201653001301226653001801239653002201257100001501279700001901294700002101313856012801334 2005 eng d a0021-899500aPreparation, characterization, and water-sorption study of polyvinyl alcohol based hydrogels with grafted hydrophilic and hydrophobic segments0 aPreparation characterization and watersorption study of polyviny a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcMAR a1129-11420 v953 a

The interpenetrating polymer network hydrogels based on poly(vinyl alcohol) were obtained by graft copolymerization of acrylamide and styrene onto polyvinyl alcohol in the presence of N,N'-methylene bisacrylamide as a crosslinking agent. The hydrogels were characterized by optical microscopy, scanning electron microscopy, infrared spectral analysis, differential scanning calorimeter, and thermogravimetric analysis. The hydrogels showed enormous swelling in aqueous medium and displayed swelling characteristics, which were highly dependent on the chemical composition of the hydrogels and pH of the swelling medium. The kinetics of water uptake and the mechanisms of water transport were studied as a function of composition of the hydrogel and pH of the swelling medium. (C) 2005 Wiley Periodicals, Inc.

10aCharacterization10aequilibrium swelling10agrafting10aIPN hydrogels10apolyvinyl alcohol1 aShukla, S.1 aBajpai, A., K.1 aKulkarni, R., A. uhttp://library.ncl.res.in/content/preparation-characterization-and-water-sorption-study-polyvinyl-alcohol-based-hydrogels-002278nas a2200265 4500008004100000022001400041245009900055210006900154260006800223300001400291490000700305520131400312653002101626653002501647653003001672653003101702653003101733653002301764653001401787100002101801700002301822700002101845700002101866856012501887 2008 eng d a0887-624X00aSynthesis and characterization of novel polybenzimidazoles bearing pendant phenoxyamine groups0 aSynthesis and characterization of novel polybenzimidazoles beari a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcSEP a5776-57930 v463 a

A novel aromatic diacid, 3, 5-dicarboxyl-4'-amino diphenyl ether, containing pendant phenoxy amine group was synthesized. Homo- and co-polybenzimidazoles containing different content of pendant phenoxyamine groups were synthesized by condensation of 3,3'-diaminobenzidine with this acid and a mixture of this acid and isophthalic acid in different ratio in polyphosphoric acid. Copolybenzimidazoles with structural variations were also synthesized based on this acid and pyridine dicarboxylic acid, terephthalic acid, adipic acid, or sebacic acid. The polymers have good solubility in polar aprotic solvents and strong acids and they form tough flexible films by solution casting. The polymers were characterized by different instrumental techniques (FTIR, TGA, DSC, XRD, etc.) and for solvent solubility, mechanical properties, inherent viscosity, and proton conductivity. The inherent viscosities of the polymers vary in the range of 0.62-1.52 dL/g. They have high thermal stability up to 475506 degrees C (IDT) in nitrogen, high glass transition temperatures (T-g) ranging from 313 to 435 degrees C and good tensile strength ranging from 58 to 125 MPa. Proton conductivity of homo polymer is 3.72 x 10(-3) S/cm at 25 degrees C and 2.45 x 10(-2) S/cm at 200 degrees C (c) 2008 Wiley Periodicals, Inc.

10aCharacterization10acopolybenzimidazoles10aHigh performance polymers10ahigh temperature materials10apendant phenoxyamine group10apolybenzimidazoles10asynthesis1 aKulkarni, Mahesh1 aPotrekar, Ravindra1 aKulkarni, R., A.1 aVernekar, S., P. uhttp://library.ncl.res.in/content/synthesis-and-characterization-novel-polybenzimidazoles-bearing-pendant-phenoxyamine-001953nas a2200229 4500008004100000022001400041245010600055210006900161260006800230300001400298490000700312520110700319653001501426653002201441653003501463653001301498100002101511700002101532700002101553700002101574856012801595 2009 eng d a0887-624X00aPolybenzimidazoles tethered with N-Phenyl 1,2,4-triazole units as polymer electrolytes for fuel cells0 aPolybenzimidazoles tethered with NPhenyl 124triazole units as po a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcMAY a2289-23030 v473 a

Polybenzimidazole (PBI) polymers tethered with N-phenyl 1,2,4-triazole (NPT) groups were prepared from a newly synthesized aromatic diacid, 3'-(4-phenyl-4H-1,2,4-triazole-3,5-diyl) dibenzoic acid (PTDBA). The obtained polymers show superior thermal and chemical stability and good solubility in many aprotic solvents. The inherent viscosities of all polymers were around 1 dL/g. They exhibit high thermal stability with initial decomposition temperature ranging from 515 to 530 degrees C, high glass transition temperature ranging from 375 to 410 degrees C, and good mechanical properties with tensile stress in the range of 66-98 MPa and modulus 1897-2600 MPa. XRD analysis indicates that these polymers are amorphous in nature. PhysicochemiCal properties such as water and phosphoric acid-uptake, oxidative stability, and proton conductivity of membranes of these polymers have also been determined. The proton conductivity ranged from 4.7 x 10(-3) to 1.8 x 10(-2) S cm(-1) at 175 degrees C in dry conditions. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2289-2303, 2009

10afuel cells10aPolybenzimidazole10asynthesis and characterization10aTriazole1 aPotrekar, R., A.1 aKulkarni, M., P.1 aKulkarni, R., A.1 aVernekar, S., P. uhttp://library.ncl.res.in/content/polybenzimidazoles-tethered-n-phenyl-124-triazole-units-polymer-electrolytes-fuel-cells-001999nas a2200241 4500008004100000022001400041245016600055210006900221260006800290300001400358490000800372520106600380653002101446653002501467653001901492653001301511100002701524700001801551700001901569700001901588700002101607856012901628 2009 eng d a0021-899500aSelf assembled hydrophobic nanoclusters of poly(methylmethcrylate) embedded into polyvinyl alcohol based hydrophilic matrix: preparation and water sorption study0 aSelf assembled hydrophobic nanoclusters of polymethylmethcrylate a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcFEB a1300-13100 v1113 a

Hydrophilic matrices containing nanosized Clusters of hydrophilic moieties have demonstrated potential applications in biomedical field. A novel hydrogel containing nanosized domains (20-35 nm) of hydrophobic moieties of poly(methyl methacrylate) (PMMA) was prepared by grafting crosslinked p ly(acrylic acid-co-methyl-methacrylate) chains onto polyvinyl alcohol (PVA) backbone using an efficient redox system. The graft copolymerization process was investigated to observe the influence of gel components on the kinetic parameters of grafting such as rate of grafting (R(g)), grafting yield (G(y)) and grafting efficiency (G(e)). The prepared graft nanohydrogel was evaluated for its water sorption potential under varying chemical composition of the gel and changing pH, temperature, and ionic strength of the swelling bath. The swelling process was also examined mechanistically and diffusion constants (D) of water molecules through the swellable nanohydrogel were also evaluated. (c) 2008 Wiley Periodicals, Inc. J ppl Polym Sci 111: 1300-1310, 2009

10agraft copolymers10ahydrophilic polymers10aNanocomposites10aswelling1 aShukla, Sandeep, Kumar1 aShaikh, Wasif1 aGunari, Nikhil1 aBajpai, A., K.1 aKulkarni, R., A. uhttp://library.ncl.res.in/content/self-assembled-hydrophobic-nanoclusters-polymethylmethcrylate-embedded-polyvinyl-alcohol-002153nas a2200253 4500008004100000022001400041245012500055210006900180260006800249300001400317490000800331520122500339653002101564653001401585653003101599653002301630653002401653653001401677100002101691700002301712700002101735700002101756856012201777 2010 eng d a0021-899500aNitrophenoxy groups containing polybenzimidazoles as polymer electrolytes for fuel cells: synthesis and characterization0 aNitrophenoxy groups containing polybenzimidazoles as polymer ele a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcSEP a3282-32920 v1173 a

Polybenzimidazoles containing different contents of pendant nitrophenoxy groups were prepared by condensation of 3,3'-diamino-benzidine with a mixture of 3,5-dicarboxyl-4'-nitro diphenyl ether and isophthalic acid (IPA) in different ratios in polyphosphoric acid. The polymers are soluble in polar aprotic solvents, they have inherent viscosities in the range of 0.75-1.10 dL g(-1) and they form tough and transparent films on solution casting. They have good thermal stability with initial decomposition temperature ranging from 380 to 416 degrees C in nitrogen, good tensile strength ranging from 56 to 65 MPa and reasonably good oxidative stability. Phosphoric acid uptake of these polymers is low compared with PBI and membranes doped with phosphoric acid exhibit good proton conductivity in the range of 6.6x 10(-3) to 1.9x 10(-2) S/cm at 25 degrees C and 1.2x 10(-2) to 4.9x 10(-2) S/cm at 175 degrees C, compared with 3.9x 10(-3) S/cm at 25 degrees C and 3.2x 10(-2) S/cm at 175 degrees C for PBI. These membranes are suitable for applications as polymer electrolyte for fuel cell and presumably for gas separation at high temperature. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 3282-3292, 2010

10aCharacterization10amembranes10apendant nitrophenoxy group10apolybenzimidazoles10aproton conductivity10asynthesis1 aKulkarni, Mahesh1 aPotrekar, Ravindra1 aKulkarni, R., A.1 aVernekar, S., P. uhttp://library.ncl.res.in/content/nitrophenoxy-groups-containing-polybenzimidazoles-polymer-electrolytes-fuel-cells-0