Relationship between the Local Dynamics and Gas Permeability of Para-Substituted Poly(1-chloro-2-phenylacetylenes)

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• 作者：Rintaro Inoue ; Toshiji Kanaya ; Toshio Masuda ; Koji Nishida ; Osamu Yamamuro
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：August 14, 2012
• 年：2012
• 卷：45
• 期：15
• 页码：6008-6014
• 全文大小：413K
• 年卷期：v.45,no.15(August 14, 2012)
• ISSN：1520-5835

文摘

Local dynamics of para-substituted poly(1-chloro-2-phenylacetylene) (PCPA) derivatives was studied using quasielastic neutron scattering. Broadening of the dynamic scattering law (S(Q,蠅)) was clearly observed for para-substituted PCPA derivatives even in the glassy state, and the observed S(Q,蠅) was well fitted to a sum of narrow and broad Lorentzians, which represent the slow and fast motions, respectively. The half-width at half-maximum (螕) of the narrow Lorentzian exhibited a positive correlation with the CO₂ and CH₄ permeability coefficients (P), while the 螕 from the broad Lorentzian hardly changed despite of the variation of permeability coefficient, indicating that only the narrow component (i.e., the slow motion) contributes to the gas permeability. The 螕 from the narrow component was approximately proportional to the diffusion coefficient (D) of the CO₂ and CH₄ gases, whereas it did not correlate with solubility coefficient (S). This implies that the local mobility affects the gas permeability through the diffusion term. The slow motion with a time scale of several tens of picoseconds seems to play an essential role for the gas permeability in glassy polymers.