Synthesis and Characterization of Liquid Crystalline Organosiloxanes Containing 4-Methoxyphenyl 4-(2-alkenyloxy)benzoate
作者:Cheng-Chih Chen、Chih-Hung Lin
DOI:10.14233/ajchem.2016.19651
日期:——
A series of new organosiloxane liquid crystalline materials based on the 4-methoxyphenyl-4-(w-alkenyloxy)benzoate as mesogenic units have been synthesized and their mesomorphic and physical properties have been characterized. A series of new disiloxanes and trisiloxanes contain 4-methoxyphenyl 4-(w-alkenyloxy)benzoate as mesogenic these were synthesized by addition of 4-methoxyphenyl 4-(w-alkenyloxy)benzoate moiety to pentamethylhydrodisiloxane or heptamethylhydrotrisiloxane catalyzed by platinum divinyl-tetramethyldisiloxane complex. The thermal properties of this new series of thermotropic liquid-crystalline siloxanes were studied by differential scanning calorimetry and polarized optical microscope. Disiloxane series compounds were not showed any liquid crystal phase. Trisiloxanes series compounds exhibited nematic liquid crystal phase. The siloxane molecule helped to reduce the melting temperature. The thermal properties of the new siloxane series exhibited a pronounced odd-even effect with the length of alkyl segment.
一系列新的有机硅氧烷液晶材料已被合成,这些材料基于4-甲氧基苯基-4-(ω-烯氧基)苯甲酸酯作为中间单位,并对其各项液晶态及物理特性进行了表征。合成了一系列新型二硅氧烷和三硅氧烷,均以4-甲氧基苯基-4-(ω-烯氧基)苯甲酸酯作为中间体,这些化合物通过将4-甲氧基苯基-4-(ω-烯氧基)苯甲酸酯基团与加热催化的五甲基氢二硅氧烷或七甲基氢三硅氧烷连接而成,催化剂为铂二乙烯-四甲基二硅氧烷复合物。利用差示扫描量热仪和偏振光显微镜研究了这一系列热致液晶硅氧烷的热特性。二硅氧烷系列化合物未显示出任何液晶相。三硅氧烷系列化合物则表现出向列液晶相。硅氧烷分子帮助降低了熔融温度。这一新硅氧烷系列的热特性表现出明显的奇偶效应,取决于烷基段的长度。