长侧基甲壳型液晶高分子的合成及性质研究  

SYNTHESIS AND CHARACERIZATION OF A SERIES OF MESOGEN-JACKETED LIQUID CRYATALLINE POLYMERS WITH LONG MESOGENIC SIDE CHAINS

作　　者：梁小朝[1] 陈小芳[1] LI Christopher Y. 沈志豪[1] 范星河[1] 周其凤[1] 

机构地区：[1]北京分子科学国家实验室高分子化学与物理教育部重点实验室北京大学化学与分子工程学院,北京100871 [2]Department of Materials Science and Engineering, Drexel University, Philadelphia PA 19104

出　　处：《高分子学报》2011年第11期1311-1319,共9页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20634010)部分资助课题

摘　　要：设计并合成了一系列尾链为不同长度烷氧基的长侧基甲壳型液晶高分子聚[2,5-二(4'-烷氧基联苯氧羰基)苯乙烯](PnCbiPCS,n=4,6,8,10,14).这些聚合物都具有良好的热稳定性.偏光显微镜及一维和二维广角X射线衍射等研究结果表明PnCbiPCS这一系列聚合物均能形成稳定的近晶A相结构,所对应的层间距随末端尾链的增长而增加,当n=4,6时层间距与侧基的理论长度相同,n≧8时层间距小于理论值,形成部分穿插的近晶A相结构.在剪切力场作用下,所有这些聚合物所形成的近晶相均易发生宏观取向,近晶层法线方向与剪切方向垂直.A series of mesogen-jacketed liquid crystalline polymers,poly[2,5-（4′-alkoxybi-phenyloxycarbonyl） styrene]（PnCbiPCS,n=4,6,8,10,14） with long mesogenic side chains,were prepared by atom transfer radical polymerization（ATRP）.Molecular weights and molecular weight distributions of the polymers were measured by gel permeation chromatography（GPC）.The liquid crystalline（LC） behavior was studied by a combination of differential scanning calorimetry（DSC）,thermogravimetric analysis（TGA）,polarized light microscopy（PLM）,one-dimensional（1D） and two-dimensional（2D） wide-angle X-ray diffraction（WAXD）,and small-angle X-ray scattering（SAXS）.All the polymers had good thermal stablility and exhibited stable LC properties,and no isotropization temperatures were observed before the onset temperatures of thermal decomposition.1D SAXS and WAXD studies revealed that PnCbiPCS could form smectic structures with the long mesogenic side chains aligned parallel to each other.The d-spacings increased with increasing aliphatic tails.2D WAXD results showed that the sheared samples exhibited Smectic A structures with the layer normal perpendicular to the shear direction.Comparing with the results of poly{2,5-bis[（para-substituted phenyl）oxycarbonyl]styrene}s,one may indicate that the length of the mesogenic group is crucial in determining the LC structure.

关 键 词：甲壳型液晶高分子 长侧基 近晶相 

分 类 号：O631.3[理学—高分子化学]