偶氮苯和氧化偶氮苯液晶基元侧链聚硅氧烷液晶的合成和性能研究

利用侧链带酰氯基的聚硅氧烷与取代偶氮苯酚进行大分子反应,合成了6种以偶氮苯氧羰基为侧链的聚硅氧烷Ⅲ_a-f;将其中的Ⅲ_a-c进行氧化,得到3种以氧化偶氮苯氧羰基为侧链的聚硅氧烷Ⅳ_a-c聚合物结构通过核磁共振、红外光谱和元素分析表征,利用偏光显微镜和差热分析仪研究了聚合物的相行为.讨论了苯环上取代基和液晶基元的中心桥键对聚合物液晶性能的影响.

Synthesis and Phase Behavior of Liquid Crystalline Polysiloxanes with Azobenzene or Azoxybenzene Mesogens in the Side Chains

In this paper we report nine polysiloxanes with azobenzene or azoxybenzene mesogens in the side chains.Polysiloxanes Ⅲ_a-f were synthesized by reacting poly (3-chlorocarbonylpropyl)methyl-siloxane-co-dimethylsiloxane with 4-(4'-substituted phenylazo)phenol or 3-methyl-4 (4'-substituted phenylazo)phenol in 74%-81% yields.By the oxidation of Ⅲ_a-c,polysiloxanes Ⅲ_a-c were further prepared.The chemical structures of these polysiloxanes obtained were confirmed by IR,¹H NMRand elemental analysis.Their phase behavior were investigated using differential scanning calorimeter (DSC) and polarizing microscope.Six of them, Ⅲ_a-c and Ⅲ_a-c,show liquid crystalline properties.