Studies on the Properties of Rigid Rod-like Polymers Long Flexible Side Chains

本文<gamma>研究了具有长烷基侧链的聚谷氨酸酯在溶液和固体中的性质，测定了它们在螺旋溶剂稀溶液中的渗透压、粘度、介电色散和偏比容。结果表明，聚合物在苯和甲苯中高度聚集，在环己酮中几乎以分子形式分散。用偏光显微镜观察了半稀溶液中的液晶结构，并对聚合物薄膜进行了动态力学测试和热分析。发现在较低的温度范围内，聚合物的侧链或多或少地结晶，并且在侧链微晶的熔融温度以上，聚合物处于液晶状态。结果表明，这些聚合物同时形成溶致液晶相和热致液晶相，在垂直于或平行于膜面的电场作用下，由溶液浇铸成取向膜。通过X射线衍射证实了分子取向。动态力学测试和热分析表明，薄膜处于亚稳态。

Properties of Poly(<gamma>-n-alkyl D-glutamate)s having long alkyl side chains were studied in solution and in solid states.The measurement of osmotic pressure, viscosity, dielectric dispersion and partial specific volume of these polymers were carried out in the dilute solution of helicogenic solvents. It was revealed that the polymers highly aggregate in benzene and toluene, and they are almost molecularly dispersed in cyclohexanone. The observation of semi-dilute solution under a polarized microscope showed the formation of cholesteric liquid crystals.Dynamic mechanical measurement and thermal analysis were performed for the films of the polymers cast from the solutions. It was found that in the lower temperature range the side chains of the polymers more or less crystallize and above the melting temperature of the side chain crystallites the polymers are in liquid crystalline state. It was shown that these polymers form both lyotropic and thermotropic liquid crystal phase.The oriented films were cast from the solutions under an electric field perpendicular or parallel to the film surface. The molecular orientation was confirmed by X-ray diffraction. The dynamic mechanical measurement and thermal analysis of the oriented films showed that these films are in metastable state.