E. Chiellini et al., SYNTHESIS AND LIQUID-CRYSTALLINE PROPERTIES OF AZOBENZEND-CONTAINING POLY(VINYL ETHER)S WITH NARROW MOLAR-MASS DISTRIBUTION, Macromolecular chemistry and physics, 196(10), 1995, pp. 3187-3196
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.