Constitutionally isomeric alicyclic polyimides: Origin of siteselectivity in the reaction of unsymmetrical dianhydride and structure-derived difference in physical properties
作者:Jiyoung Choi、Kazuaki Shirai、Toshio Takayama、Kengo Akagawa、Kazuaki Kudo
DOI:10.1002/pola.26231
日期:2012.10.15
isomeric alicyclic polyimides (PIs), head‐to‐head (HH) and random types, were successfully synthesized on the basis of a siteselective ring opening reaction of an unsymmetric spiroalicyclic dianhydride, rel‐[1R,5S,6R]‐3‐oxabicyclo[3,2,1]octane‐2,4‐dione‐6‐spiro‐3′‐(tetrahydrofuran‐2′,5′‐dione), with using several kinds of diamines only by changing reaction procedures. A model reaction study revealed that the
基于不对称螺环脂族二酐rel [1 R,5 S,6 R] -3-氧杂双环[3,2,1]辛烷-2,4-二酮-6-螺代3'-(四氢呋喃-2',5'-二酮),仅通过改变反应程序使用几种二胺。模型反应研究表明,二酐反应中位点选择性的起因是由于嵌入双环[3.2.1]系统的六元酸酐的反应性增强和螺环中五元酸酐的反应性降低[4.5]系统。与随机PI相比,HH-PI显示出更高的玻璃化转变温度和更高的介电常数。PI膜的比重表明,物理性质的差异是由于两种组成异构的PI的堆积密度不同所致。这是具有不同物理性质的两种无定形缩聚物在结构上均等异构的第一个例子。