侧链型Schiff碱液晶研究——单体的合成与聚合

Synthesis and Polymerization of Side chain Schiff Base Liquid Crystal Monomers

对具有Ｎ－（对甲基丙烯酰氧基苄叉基）取代苯胺骨架的一系列侧链型Ｓｃｈｉｆ碱液晶单体合成进行了研究，苯胺环上的取代基为卤素、强吸电子基及大体积基团，考察了取代基对液晶性质的影响。当取代基为４－氯，４－溴时，单体呈狭窄之液晶区间，而２，４－二氯取代物则无液晶性。当苯胺环上带有４－苯基的单体时，都呈宽的液晶区间。同时还对相应单体的自由基聚合及聚合物的相行为进行了研究。

The synthesis and polymerization of several homologous Schiff bases with basic skeleton of N (p methacryloyloxy benzylidene) anilines have been investigated. The monomers, with p chloro, p bromoaniline moiety, show very narrow mesomorphism. The monomers, these with 2,4 dichloro and p nitro substitutent do not exhibit mesomorphism. The monomeric Schiff bases with biphenyl moiety, N (p methacryloyloxy benzlidene) p aminobithenyl, show a wide temperature range of mesophase and high thermostability. Chemical structures of these compounds were determined by IR, 1H NMR and elemental analysis. Their liquid crystal properties were tested by hotstage microscopy and defferential scanning calorimetry. The radical polymerization of some monomers also has been examined. The polymers exhibit liquid crystalline behavior although the mesogenic side chains are directly fixed to the polymethacrylate backbone.