Synthesis of Novel Block Copolymers Containing Liquid Crystalline Segments by Anionic Living Polymerization

在四氢呋喃（THF）中，用不同的引发剂进行了6-（对甲氧基双酚氧基）甲基丙烯酸酯（1）和6-（对氰基双酚氧基）甲基丙烯酸酯（2）的阴离子聚合。在特定的条件下，（1）和（2）都进行了阴离子活性聚合，定量地得到了分子量调节良好和分子量分布极窄（Mw/Mn<1.1）的聚合物。通过使用这些活性聚合物，成功地制备了（1）或（2）与苯乙烯或甲基丙烯酸甲酯的新型明确的嵌段共聚物。其结构为AB、BA、阿坝和BAB型嵌段共聚物。它们具有良好控制的分子量和组成以及窄的分子量分布。为了系统地研究热致转变行为与聚合物结构的关系，（3 000-30 000）和具有不同分子量的嵌段共聚物（5 000-100 000）和组成（20-80mol%）的聚（1），研究了聚（1）在结晶相、近晶A相和各向同性相之间的热致转变行为。聚（2）s，观察到双相液晶相。聚（2）的分子量也影响液晶相的温度范围。在苯乙烯和（1）的嵌段共聚物中，用电子显微镜和小角X-射线方法观察到由于液晶和无定形聚苯乙烯嵌段引起的微相分离。在液晶相温度范围内，首次发现了微区周期随温度的减小。为此提出了一种新的模式。另一方面，在苯乙烯和（2）的嵌段共聚物中没有观察到这种现象，尽管这些嵌段共聚物是微相分离的。

Anionic polymerization of 6- (p-methoxybiphenoloxy) methacrylate (1) and 6- (p-cyanobiphenoloxy) methacrylate (2) were carried out in THF with various initiators. Under specified conditions, both (1) and (2) underwent anionic living polymerization to afford quantitatively the polymers of well-regulated molecular weights and of extremely narrow molecular weight distributions (Mw/Mn<1.1). By using these living polymers, novel well-defined block copolymers of (1) or (2) with stirene or methyl methacrylate were successfully prepared. Their structures are AB,BA,ABA and BAB types of block copolymers. They possessed well-controlled molecular weights and compositions and narrow molecular weight distributions. In order to investigate systematically the relationship between thermotropic transition behavior and polymer structure, homopolymers with different molecular weights (3 000-30 000) and block copolymers with different molecular weights (5 000-100 000) and compositions (20-80mol%) were prepared.In a series of poly (1) s, the thermotropic transition behavior between crystal, smectic A,and isotropic phases was observed to be examined with a function of molecular weight. With poly (2) s, nematic liquid crystalline phase was observed. The temperature range showing liquid crystalline phase was also influenced by the molecular weight of poly (2). In the block copolymers of stirene and (1), microphase separation due to liquid crstalline and amorphous polystirene blocks was observed by electron microscopy and small-angle X-ray methods. Decrease of period of microdomain with temperature was first found in the temperature range showing liquid crystalline phase. A new model was proposed for this. On the otherhand, this phenomenon was not observed in the block copolymers of stirene and (2), although these block copolymers were microphase-separated.