甲壳型液晶高分子的化学结构及其与性能间关系的研究

设计并合成了7种新型甲壳型液晶高分子,研究了液晶基元的化学结构和立体效应对单体及其聚合物液晶性的影响.发现在液晶基元的末端引入极性或可极化的原子基团提高了单体的熔点和液晶相的热稳定性;液晶基元的长径比越大,单体的熔点和清亮点越高;聚合使单体的液晶稳定性增加、液晶相温度范围变宽;侧链液晶基元的极性、刚性和空阻越大,聚合物的玻璃化温度越高;酰胺基团无论是在分子的末端还是在连接部位,都使单体的熔点和聚合物的玻璃化温度提高,但在分子末端时液晶相较稳定,作为中心桥键时不利于液晶相的稳定形成.

A Study of the Relationship Between Chemical Structure and Properties for Mesogen-jacketed Liquid Crystal Polymers

Seven novel mesogen jacketed liquid crystal polymers were designed and synthesized. The effects of chemical structure and steric features on liquid crystalline phase forming were studied. It was found that the introduction of polar or polarable group at the end of the mesogen units could increase the melting point and clear point of monomers. The bigger the axial ratio of mesogen units, the higher the melting point and clear point. The stability of liquid crystalline phase was enhanced by polymerization. The stronger of the polarity, rigidity and steric requirement of the mesogen units, the higher the glass transition temperature of the polymers. The amide group can increase the melting point of monomers and glass transition temperature of polymers no matter it was used as the end group or linkage of the mesogen units. However, the stability of liquid crystalline phase was increased by the amide end groups and decreased by the amide linkages.