【摘要】 采取两步法合成侧链型芳香族偶氮基聚氨酯,并应用FT-IR、VPO、DSC和TPOM表征聚氨酯的结构及液晶性。MDI系列聚氨酯由于其主链刚性较大,不出现液晶相,而HDI系列聚氨酯则可出现液晶相,并随着由扩链剂引入主链的“柔性间隔基”的柔性和长度增加,“去偶”作用增强,其液晶相的转变温度和有序性也随之提高。更多还原

【Abstract】 A series of side chain polyurethane (PU) with aromatic azo- group were synthesized by two step polymerization and the chemical structure and LC properties of PU were characterized by means of FT - IR, VPO, DSC and TPOM . Because of the hindrance of hard segment in the backbone, the LC phase of MDI - type PU could not be found, but HDI - type PU could form LC phase by decoupling of flexible spacer in its backbone. And as the flexibility and length of flexible spacer increased by different chain extender, the transition temperature and ordered degree of LC phase of HDI - type PU also rise.更多还原