侧链胆甾液晶聚合物及弹性体的液晶性能研究

把胆甾液晶单体 4 烯丙氧基苯甲酸胆甾醇酯 (Mch)分别和向列液晶单体 4 烯丙氧基苯甲酰氧基 4′ 甲氧基苯 (Mn) ,向列液晶交联剂 2 叔丁基对苯二酚双 [4 (6 丙烯酰氧基己氧基 )苯甲酸酯 ](Mnc)接枝到聚硅氧烷链上 ,得到系列侧链液晶聚合物Pn 系列和液晶弹性体Pe 系列 .通过热分析、偏光显微分析和X 射线分析等手段分别研究了向列液晶单体和向列液晶交联剂对含同一胆甾液晶基元聚合物的影响 .结果表明 ,向列液晶单体的摩尔百分比在 80 %以下 ,液晶聚合物Pn 系列为胆甾型液晶 ,在研究的范围内 ,液晶弹性体Pe 系列也为胆甾型液晶 ,Pn 系列和Pe 系列都具有较宽的液晶相范围 ,热分解温度均在 2 80℃以上 .

STUDY ON MESOMORPHIC PROPERTIES OF SIDE-CHINA CHOLESTERIC POLYMERS AND ELASTOMERS

The synthesis of side chain cholesteric liquid crystalline polymers (P n series) and elastomers (P-e series) containing both 4-allyloxybenzoylcholeseterate (M ch) and 4-allyloxybenzoyloxy-4′-methoxyphenyl (M n) or 2-tert-butylhydroquinone di(4-(b-acryloyloxy hexyloxy)benzoate) (M nc) mesogenic side groups was described.The chemical structures of the obtained polymers and elastomers were confirmed by FT-IR spectroscopy.Their mesomorphic properties and phase behavior were investigated with POM,DSC,TGA and X-ray measurements.The liquid crystalline polymers P n1～P n8 and elastomers P e1～P e7 exhibited cholesteric grandjean texture or oily streak texture.In P n series,with increasing the concentration of the cholesteric mesogenic M ch,the glass transition temperature(T g) increased from 8 7℃ to 65 7℃,and the clearing point temperature(T c) increased from 42 0℃ to 251 8℃.In P-e series,with increasing the concentration of the nematic liquid crystalline crosslinking agent M nc,T g decreased from 65 7℃to 52 7℃,and T c had no significant change.When the concentration of M nc was greater than 8 mol%,the DSC curves of P e6 and P e7 did not show the clearing point temperatures,but POM observations exhibited the grandjean texture,which did not disappear until their decomposition.The polymers P n1～P n11 and elastomers P e1～P e7 had wide mesomoephic temperature ranges.TGA measurements showed that the temperature at which a 5% mass loss occurred was higher than 280℃ for all the liquid crystalline polymers and ealastomers.