含供吸电子的手性液晶聚合物的合成与性能

将有供电子基团的手性单体M1和含吸电子基团的单体M2接枝到聚甲基含氢硅氧烷上,得到系列手性液晶聚合物,其中,手性单体的摩尔分数为0～50%.通过红外光谱(IR)、核磁共振谱(1HNMR)、差示扫描量热法(DSC)、偏光显微分析法(POM)、热失重分析法(TGA)、X射线分析等手段研究了手性单体的含量及供吸基团对侧链胆甾型液晶聚合物性能的影响.结果表明P1～P8都有液晶性且为胆甾型液晶聚合物,系列液晶聚合物的tg随手性单体含量的增加而增加,ti随手性单体含量的增加而降低,P1～P8具有较宽的液晶相范围,热稳定性较高,质量损失5%时的热失重温度均在300℃左右.

Synthesis and Properties of Chiral Liquid Crystal Polymers Containing Donor-Acceptor

The electron-donating chiral monomer 2-(4-allyloxy benzoate)-5-{4-(4-propoxy)phen-yl] phenyloxycarbonyl} pentanoic acid isosorbide (M1) and the electron-accepted liquid crystal monomer 4-(10-undecylen-1-yloxycarbonyl)benzoic acid biphenyl cyanogen (M2) were grafted onto the backbone of polymethylhydrosiloxane (PMHS). The mesomorphic properties of cholesteric liquid crystalline polymers P1~P8 containing different contents of M1 from 0 to 50 mol% were investigated by FTIR, ¹HNMR spectra, DSC, POM, TG and X-ray. Experiment results showed that P1~P8 are the thermotropic cholesteric liquid crystal polymers and that glass transition temperature tg increases and isotropic temperature ti decreases with the increasing content of M1 and the mesomorphic temperature ranges of the polymers are wider. The thermal stability of the polymers is about 300°C with only 5 wt% lost.