Study of Transport Properties and Structure of Extended-Chain Polymers: Diffusion and Solubility of Gases

摘要

The study of the transport properties in extended chain polymers has added to the understanding of relations between their macroscopic and microscopic properties. There was a need to determine the extent to which a new class of high strength extended chain polymers absorb various vapors and how the vapor moves within the materials, which have a highly anisotropic fibrous morphology. The main polymer studied as a representative of the class is poly p-phenylene benzobisthiazole (PPBT). An abnormally large heat of sorption (solution) and paradoxical data from two experimental systems with somewhat different conditions are attributed to a large volume fraction of microcavities in PPBT. This hypothesis was shown to be consistent by using the theory of dual sorption. A statistical mechanical model due to diBenedetto was modified to correlate the activation energy with rotation energy and to make possible the prediction of the parallel diffusion coefficient.