SYNTHESIS AND LIQUID-CRYSTALLINE PROPERTIES OF AZOBENZEND-CONTAINING POLY(VINYL ETHER)S WITH NARROW MOLAR-MASS DISTRIBUTION

A series of new liquid crystalline (LC) poly(vinyl ether)s with differ ent molar masses was synthesized via a two-step procedure involving th e preparation of functional matrices by living cationic polymerization of an omega-chloroalkyl vinyl ether monomer followed by a grafting re action of an azobenzene mesogenic unit onto them. By appropriately adj usting the experimental conditions, it was possible to predetermine th e molar mass characteristics of the LC polymers. Each of the parent an d modified poly(vinyl ether)s had a narrow molar mass distribution. Th e LC polymers were semicrystalline and formed a nematic mesophase, ena ntiotropic or monotropic in character. The transition temperatures inc reased with increasing molar mass up to a limiting value and then rema ined nearly constant. Accordingly, poly(vinyl ether)s with predetermin ed molar mass and narrow molar mass distribution could be prepared.