02309nas a2200229   4500008004100000022001400041245010400055210006900159260007300228300001200301490000800313520146100321653001401782653001901796653002201815653001301837653002201850100002801872700002501900700002201925856013201947       2006                        eng d  a0376-738800aEnhancement of gas permeation properties of polybenzimidazoles by systematic structure architecture0 aEnhancement of gas permeation properties of polybenzimidazoles b  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a161-1690 v2863 a<p>Systematic structural variations in thermally stable polybenzimidazole (PBI) are explored that led to a substantial improvement in gas permeation properties. Physical property determinations revealed that incorporation of hexafluoroisopropylidene and tert-butyl groups led to amorphous polymers with slightly lowered thermal stability and decreased chain packing. PBI based on 4,4'-(hexafluoroisopropylidene)bis(benzoic acid) and 5-tert-butyl isophthalic acid exhibited 10-40 times higher permeability, while changes in selectivities for industrially important pairs ranged from modest decrease of 75% or less than that of PBI based on isophthalic acid. The O-2/N-2 selectivity was almost doubled in case of PBI based on 5-tert-butyl isophthalic acid. Gas diffusion coefficients were estimated from solubility and permeability coefficient determinations. These, along with dual-mode sorption parameters estimated from sorption isotherms provided an insight towards variations in permeation behavior. The permeability predictions for heavier gases in isophthalic acid based PBI correlated well with physical properties. The occurrence of permeation characteristics (especially P-H2 and P-H2/P-N2) near Robeson's upper bound, high thermal stability and good solvent solubility achieved by these structural modifications depicted the potential of this family of polymers as gas separation membrane materials. (c) 2006 Elsevier B.V. All rights reserved.</p>10aDiffusion10aGas permeation10aPolybenzimidazole10aSorption10athermal stability1 aKumbharkar, Santosh, C.1 aKaradkar, Prasad, B.1 aKharul, Ulhas, K.  uhttps://library.ncl.res.in/content/enhancement-gas-permeation-properties-polybenzimidazoles-systematic-structure-architecture-002506nas a2200253   4500008004100000022001400041245008900055210006900144260006700213300001200280490000700292520159100299653003501890653002501925653001501950653002501965653002201990100002602012700002602038700002402064700002202088700002802110856011402138       2016                        eng d  a0959-810300aSynthesis and properties of poly(arylene ether)s based on 3-pentadecyl 4,4'-biphenol0 aSynthesis and properties of polyarylene ethers based on 3pentade  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcMAY  a567-5760 v653 a<p>A new biphenol, 3-pentadecyl 4,4-biphenol, was synthesized starting from 3-pentadecylphenol and was polycondensed with 4,4-difluorobenzophenone, 1,3-bis(4-fluorobenzoyl)benzene and bis(4-fluorophenyl)sulfone to obtain poly(arylene ether)s with biphenylene linkages in the backbone and pendent pentadecyl chains. Inherent viscosities and number-average molecular weights (M-n) of the poly(arylene ether)s were in the range 0.50 - 0.81 dL g(-1) and 2.2 x 10(4) - 8.3 x 10(4), respectively. Detailed NMR spectroscopic studies of the poly(arylene ether)s indicated the presence of constitutional isomerism which existed because of the non-symmetrical structure of 3-pentadecyl 4,4-biphenol. The poly(arylene ether)s readily dissolved in common organic solvents such as dichloromethane, chloroform and tetrahydrofuran and could be cast into tough, transparent and flexible films from their chloroform solutions. The poly(arylene ether)s exhibited T-g values in the range 35-60 degrees C which are lower than that of reference poly(arylene ether)s without pentadecyl chains. The 10% decomposition temperatures (T-10) of the poly(arylene ether)s were in the range 410-455 degrees C indicating their good thermal stability. A gas permeation study of poly(ether sulfone) containing pendent pentadecyl chains revealed a moderate increase in permeability for helium, hydrogen and oxygen. However, there was a large increase in permeability for carbon dioxide which could be attributed to the internal plasticization effect of pendent pentadecyl chains. (c) 2016 Society of Chemical Industry</p>10acashew nut shell liquid (CNSL)10agas permeation study10apentadecyl10apoly(arylene ether)s10athermal stability1 aTawade, Bhausaheb, V.1 aShaligram, Sayali, V.1 aValsange, Nitin, G.1 aKharul, Ulhas, K.1 aWadgaonkar, Prakash, P.  uhttps://library.ncl.res.in/content/synthesis-and-properties-polyarylene-ethers-based-3-pentadecyl-44-biphenol