用核磁共振方法研究聚硅氧烷类液晶侧链的结构异构

A STUDY ON STRUCTURAL ISOMERISM OF SIDE CHAIN IN LIQUID CRYSTALLINE POLYSILOXANE BY NUCLEAR MAGNETIC RESONANCE METHOD

近十多年来,侧链型液晶聚合物的研究日益活跃。研究结果表明,这类聚合物将作为新的功能材料,在化合物分离、信息存储和显示装置上得到实际应用。聚硅氧烷类侧链型液晶是迄今研究得最多,很有潜在实用价值的一种侧链型高分子液晶。它通常是用含中介基团的烯烃与聚甲基氢硅氧烷通过硅氢化反应制得的。文献中给出的反应式都可表示为:

An evidence has been found by 1H and 13C NMR techniques for the presence of structural isomerism of side chain in liquid crystalline polysiloxane due to α- and β-additions of alke-ne monomers. A liquid crystalline polysiloxane from poly (methylhydrosiloxane) and 4-(al-lyloxy) benzoyl-4-methoxyphenyl contains as many as 42% α-addition isomeric side chains based on our NMR data. It is thus pointed out that the strength change of Si-H absorption band in IR or NMR spectra can only reflect the extent of completion of hydrosilation, it does not necessarily mean the liquid crystalline polysiloxane produced contains β-addition iso-meric side chains only.