热致液晶聚酯酰亚胺的WAXD研究

WAXD STUDY ON THERMOTROPIC LIQUID CRYSTAL POLY(ESTER IMIDE)S

采用Ｘ射线衍射仪、示差扫描热分析仪及偏光显微镜对热致液晶聚酯酰亚胺进行了研究。ＤＳＣ曲线上都有明显的玻璃化转变（Ｔ＿ｇ）及两个熔融峰（Ｔ＿（ｍ１）、Ｔ＿（ｍ２）），表明聚合物具有明显的液晶性；ＷＡＸＤ曲线上在２θ＝２０°左右可观察到较强的衍射峰，在２θ＜１３°的小角范围内也可观察到多个比较尖锐的衍射峰，前者表明分子链横向排列，间距在４．５～５Ａ，后者表明聚合物分子径向采取较完美的层状超分子结构顺序排列，以上结果证实了共聚物是近晶型结构；偏光显微镜下观察到了棒状或小锥状的近晶型液晶的典型织构，进一步支持了ＷＡＸＤ所得结论。

A series of thermotropic liquid crystal poly (ester imide) s derived from 1, 5-pentamethylenediaine, 1, 10-decanediamine, and p-phenylenebis-(trimilitic) dianhydride were synthesized via a solution polycondensation process . The poly (ester imide) s were characterized by WAXD,DSC measurements, and polarizing microscope. WAXD measurements indicated that sharp reflections were detectable at beth 2θ<13°and 2θ=20°, which fit a typical smectic WAXD pattern.the results revealed that the samples posessed a sharp endotherm (T_(ml)) and a second endotherm (T_(m2)) which indicated the phase transitions. Under polarizing miscroscope,the samples showed a obvious birefringent patterns in the temperature range between T_(m1) and T_(m2), and small conic texture or batonnets texture (typical smectic granular texture) were observed.