Novel side chain type cardo poly(aryl ether sulfone) bearing pendant sulfoalkyl groups for proton ex
A series of cardo poly(aryl ether sulfone) copolymers bearing pendant hydroxyl ethyl groups CH(2)CH(2)OH) were synthesized from a new biphenol monomer 2 (2 hydroxyethyl) 3,3 bis(4 hydroxyphenyl)isoindolin 1 one (PPH OH) 4,4' biphenol(BP) and 4,4' difluorodiphenylsulfone (DFDPS) Sulfonic acid groups were readily grafted to the copolymers by reaction of the hydroxyl group with 1,3 propanesultone. The resulting sulfonated copolymers SPES C X (where X refer to the content of PPH OH in the bisphenol monomers) contain side chain sulfoalkyl groups CH(2)CH(2) O CH(2)CH(2)CH(2)SO(3)H) TEM photographs revealed that SPES C 100 membrane exhibited characteristic hydrophilic/hydrophobic microphase separated morphology with small interconnected and hydrophilic clusters (1.5 2 nm) Such microphase separated morphology renders the membrane high proton conductivity of 0.056 S/cm (IEC 1.41 mequiv./g) and low dimensional changes of SPES C 100 at room temperature. SPES C X membranes exhibited the methanol permeability in the range of 13.8 5.3 x 10( 8) cm(2)/s, which were much lower than those of SBPES (8.7 x 10( 7) cm(2)/s) and Nafion 117 (2.4 x 10( 7) cm(2)/s) (C) 2010 Elsevier B.V. All rights reserved.