@article { ISI:000226756100018, title = {Preparation, characterization, and water-sorption study of polyvinyl alcohol based hydrogels with grafted hydrophilic and hydrophobic segments}, journal = {Journal of Applied Polymer Science}, volume = {95}, number = {5}, year = {2005}, month = {MAR}, pages = {1129-1142}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

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{\textquoteright}-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.

}, keywords = {Characterization, equilibrium swelling, grafting, IPN hydrogels, polyvinyl alcohol}, issn = {0021-8995}, doi = {10.1002/app.21344}, author = {Shukla, S. and Bajpai, A. K. and Kulkarni, R. A.} } @article { ISI:000258981000008, title = {Synthesis and characterization of novel polybenzimidazoles bearing pendant phenoxyamine groups}, journal = {Journal of Polymer Science Part A-Polymer Chemistry}, volume = {46}, number = {17}, year = {2008}, month = {SEP}, pages = {5776-5793}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

A novel aromatic diacid, 3, 5-dicarboxyl-4{\textquoteright}-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{\textquoteright}-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.

}, keywords = {Characterization, copolybenzimidazoles, High performance polymers, high temperature materials, pendant phenoxyamine group, polybenzimidazoles, synthesis}, issn = {0887-624X}, doi = {10.1002/pola.22892}, author = {Kulkarni, Mahesh and Potrekar, Ravindra and Kulkarni, R. A. and Vernekar, S. P.} } @article { ISI:000265316800007, title = {Polybenzimidazoles tethered with N-Phenyl 1,2,4-triazole units as polymer electrolytes for fuel cells}, journal = {Journal of Polymer Science Part A-Polymer Chemistry}, volume = {47}, number = {9}, year = {2009}, month = {MAY}, pages = {2289-2303}, publisher = {JOHN WILEY \& SONS INC}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Polybenzimidazole (PBI) polymers tethered with N-phenyl 1,2,4-triazole (NPT) groups were prepared from a newly synthesized aromatic diacid, 3{\textquoteright}-(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

}, keywords = {fuel cells, Polybenzimidazole, synthesis and characterization, Triazole}, issn = {0887-624X}, doi = {10.1002/pola.23310}, author = {Potrekar, R. A. and Kulkarni, M. P. and Kulkarni, R. A. and Vernekar, S. P.} } @article { ISI:000261660200019, title = {Self assembled hydrophobic nanoclusters of poly(methylmethcrylate) embedded into polyvinyl alcohol based hydrophilic matrix: preparation and water sorption study}, journal = {Journal of Applied Polymer Science}, volume = {111}, number = {3}, year = {2009}, month = {FEB}, pages = {1300-1310}, publisher = {JOHN WILEY \& SONS INC}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

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

}, keywords = {graft copolymers, hydrophilic polymers, Nanocomposites, swelling}, issn = {0021-8995}, doi = {10.1002/app.29155}, author = {Shukla, Sandeep Kumar and Shaikh, A. Wasif and Gunari, Nikhil and Bajpai, A. K. and Kulkarni, R. A.} } @article { ISI:000279958200023, title = {Nitrophenoxy groups containing polybenzimidazoles as polymer electrolytes for fuel cells: synthesis and characterization}, journal = {Journal of Applied Polymer Science}, volume = {117}, number = {6}, year = {2010}, month = {SEP}, pages = {3282-3292}, publisher = {JOHN WILEY \& SONS INC}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Polybenzimidazoles containing different contents of pendant nitrophenoxy groups were prepared by condensation of 3,3{\textquoteright}-diamino-benzidine with a mixture of 3,5-dicarboxyl-4{\textquoteright}-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

}, keywords = {Characterization, membranes, pendant nitrophenoxy group, polybenzimidazoles, proton conductivity, synthesis}, issn = {0021-8995}, doi = {10.1002/app.30279}, author = {Kulkarni, Mahesh and Potrekar, Ravindra and Kulkarni, R. A. and Vernekar, S. P.} }