The hydrophilic and hydrophobic block length of a series of sulfonated multi-block copolymers based on poly(arylene ether sulfone) (BPSH-BPS) was controlled to be with the equal length of 5k, 10k and 15k but the fixed ion exchange capacity(IECw).Viscoelasticity of these materials were investigated as a function of block length, frequency, and temperature ranging from 200 to 250oC using a TA Q800 dynamic mechanical analyzer (DMA). Increased block length yield the drop of the relaxation time and glassy state modulus but not influencing shift factor function as temperature, which was well illustrated by Williams-Landel-ferry (WLF ) equation. Small Angle X-ray Scatter (SAXS) indicated longer block length induced more ionic cross-link density based on dry membrane volume as well as expanded domain size. d-space is found to be 21.1, 31.4 and 36.4 nm respectively. Lower free volume fraction value corresponding to Bondi group contribution method was found in longer block length copolymers. Lowest hydrogen permeability of 2.46 Barrers at 30oC and 4atm was observed in BPSH-BPS(15k:15k) copolymers.

Correlation of multiblock copolymer ionomer structure with viscoelasticity and gas transport properties

242nd National Meeting (2011)

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