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This study explores the influence of meta/para and ortho-position functional group structures on gas transport properties of two isomeric polyimides and their thermally rearranged (TR) polymers. The diamine isomers, 3,3′-dihydroxy-4,4′-diamino-biphenyl (p-HAB) and 4,4′-dihydroxybiphenyl-3,3′-diamino-biphenyl (m-HAB), were polymerized with 2,2′-bis-(3,4-dicarboxy-phenyl) hexafluoropropane dianhydride...
There is a need for polymeric capacitors with improved energy storage density and thermal stability. In this work, the effect of polymer molecular structure and symmetry on Tg, breakdown strength, and relative permittivity were investigated. A systematic series of four amorphous poly(arylene ether ketone)s were compared. Two of the polymers had symmetric bisphenols while the remaining two had asymmetric...
Isomeric polyhydroxyimides based on 3,3′-diamino-4,4′-dihydroxybiphenyl (m-HAB) or 3,3′-dihydroxy-4,4′-diaminobiphenyl (p-HAB) with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) were prepared via an ester-acid monomer. The polyhydroxyimides were then acetylated using acetic anhydride to change the ortho-functional groups on the polymer chains. These ortho-functional polyimides were...
A series of polybenzimidazoles containing sulfonyl groups were synthesized in Eaton's reagent for high temperature H2/CO2 separation membranes. The key monomer, 3,3′,4,4′-tetraaminodiphenylsulfone, was prepared via a novel and economical synthetic route starting from 4,4′-dichlorodiphenylsulfone. These polybenzimidazoles with sulfonyl moieties had enhanced solubilities in dipolar aprotic solvents...
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