Over the last 25 years, our laboratory has employed dynamic thermal analysis techniques (i.e. dynamic mechanical analysis; broadband dielectric spectroscopy) in combination with static characterization methods for the investigation of glass-rubber and sub-glass molecular relaxations in polymer systems. Variations in polymer composition, chain architecture and processing history have been used to elucidate relaxation mechanisms in semi-crystalline polymers, blends and copolymer networks. This presentation will provide an overview of these studies, with an emphasis on investigations related to the design of rubbery copolymer networks for use as gas separation membranes. Systematic modifications in network composition, crosslink density and the strategic introduction of chain pendants have been applied to tailor the chemical and physical free volume characteristics of these networks and their resulting gas separation performance. In this context, dynamic mechanical and broadband dielectric studies provide valuable insight as to inherent segmental mobility and motional constraint, relaxation environment, and their influence on small molecule transport.

Molecular relaxation studies of crystalline polymers, blends and copolymer networks

253rd National Meeting (2017)

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