两种介晶基元对热致性液晶共聚酯酰亚胺性能的影响

Effect of Two Mesogenic Units on the Properties of Thermotropic Liquid Crystalline Copoly(Ester-Imide)s

以4,4’-二氨基苯酚癸二酸酯(DAED)与对-亚苯基-双苯偏三酸酯二酐(BTAH)和3,3’,4,4’-联苯四羧酸二酐(BP-DA)在N-甲基吡咯烷酮(NMP)中制备共聚酯酰胺酸,通过三乙胺缔合共聚酯酰胺酸的羧酸官能团抑制共聚物中的酯键和酰胺键的降解,然后热环化制备了四种半芳族共聚酯酰亚胺。四种共聚物的结晶度随着BTAH单元的含量从10%增加到40%,结晶度从18.8%减小到9.3%。由于BTAH与BPDA两种介晶基元间的协同效应,BTAH含量为10%,20%和40%的三种共聚物形成了典型的丝状液晶织构,含量为30%的共聚物形成了反向壁液晶织构。随着BTAH含量从10%增加到40%,向列型液晶相的熔点从370℃降低到349℃。

Bis（trimellitic acid anhydride） phenyl ester（BTAH） with different ratios was copolymerized with 3,3’,4,4’-biphenyl tetracarboxylic dianhydride（BPDA） and di-p-aminophenyl ester of dicarboxylic acids（DAED） to give high molecular weight four copoly（ester-amic acid）s,then copoly（ester-amic acid）s salt was formed by tertiary amine.The copoly（ester-amic acid）s salt as converted into copoly（ester-imide）s by thermal imidization.Properties of the resulting four copoly（ester-imide）s were characterized by polarizes light microscopy（PLM）,differential scanning calorimetry（DSC） and wide-angle X-ray diffraction（WAXD）.When the content of BTAH units rises from 10% to 40%,the degree of crystallinity decreases from 18.8% to 9.3%.When the content of BTAH is 10%,20% and 40%,respectively,typical ＂thread schlieren texture＂ is observed.When the content of BTAH is 30%,the ＂inversion walls texture＂ is foamed.When the content of BTAH units increases from 10% to 40%,the melting transition temperatures decrease from 370 ℃ to 349 ℃.