GAS-TRANSPORT IN POLY(SILYLPROPYNES) - THE CHEMICAL-STRUCTURE POINT-OF-VIEW
GAS-TRANSPORT IN POLY(SILYLPROPYNES) - THE CHEMICAL-STRUCTURE POINT-OF-VIEW
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DOI：
10.1021/ma00075a013
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发表时间：
1993-11-08
期刊：
影响因子：
5.5
通讯作者：
TIEN, CF
中科院分区：
文献类型：
--
作者：
SAVOCA, AC;SURNAMER, AD;TIEN, CF
聚[1-（三甲基硅基）丙炔]（PTMSP）具有任何已知聚合物中最高的气体渗透性。1理解PTMSP极高气体渗透性的结构起源应有助于其他高气体渗透性玻璃态聚合物的设计。一系列密切相关的聚合物的同源系统的调查结果提示我们提供一个结构/性能的理由来解释高透气性的PTMSP。合成以下聚合物：聚[1-（正烷基二甲基甲硅烷基）丙炔]; A-E）、聚[1-（异丙基二甲基甲硅烷基）丙炔]; F）、聚[1-（苯基二甲基甲硅烷基）丙炔]; G）和聚[1-[对-（三甲基甲硅烷基）苯基]丙炔]; H）。本文讨论了聚合物构象与主链共轭的空间要求、动态力学谱和提出的聚合机理的关系。侧基的临界表面张力被用来定性地合理化聚（硅基丙炔）的分子间相互作用。测量气体渗透率（P）。对于聚合物A-E，随着正烷基的链长减小，透气性增加。聚[1-（异丙基二甲基甲硅烷基）丙炔]（F）和聚[1-（正丙基二甲基甲硅烷基）丙炔]（C）以及聚合物G和聚合物H之间的氧渗透系数P（O2）的巨大差异可以基于侧链缔合的微妙但重要的伦敦力来解释。我们的结论是，PTMSP的非常高的气体渗透性是聚合物基质内的大的过量自由体积的结果，其本身归因于（1）刚性和不规则的主链构象和（2）屏蔽主链的侧链的低链间吸引力。
Poly[1-(trimethylsilyl)propyne] (PTMSP) has the highest gas permeability of any known polymer.1 Understanding the structural origins of the exceedingly high gas permeability of PTMSP should facilitate the design of other highly gas permeable glassy polymers. Results of a systematic investigation of a homologous series of closely related polymers prompt us to offer a structure/property rationale to explain the high gas permeability of PTMSP. The following polymers were synthesized: poly[1-(n-alkyldimethylsilyl)propyne]; A-E), poly[1-(isopropyldimethylsilyl) propyne]; F), poly[1-(phenyldimethylsilyl)propyne]; G), and poly[1-[p-(trimethylsilyl)phenyl]propyne]; H). Polymer conformation is herein discussed in relation to the steric requirement for main-chain conjugation, dynamic mechanical spectra, and a proposed mechanism of polymerization. The critical surface tension of pendant groups was used to qualitatively rationalize the intermolecular interactions for poly(silylpropynes). Gas permeability (P) was measured. For polymers A-E, as the chain length of the n-alkyl group decreases, the gas permeability increases. The large differences in the oxygen permeability coefficient, P(O2), for poly[1-(isopropyldimethylsilyl)propyne] (F) and poly[1-(n-propyldimethylsilyl)propyne] (C) as well as those between polymer G and polymer H can be explained on the basis of the subtle but important London forces of side-chain association. Our conclusion is that the extraordinarily high gas permeability of PTMSP is a consequence of large excess free volume within the polymer matrix which is itself ascribed to (1) the rigid and irregular main-chain conformation and (2) the low interchain attraction force of the side chains which shield the main chain.