Vinyl monomers having a Schiff-base structure were synthesized and their th
ermal and photopolymerization behavior was explored for different phases of
the monomers. It was found that conversion of the monomers increased with
temperature in the nematic phase, while it decreased in the isotropic phase
. This result suggests that the polymerization behavior may be affected by
the molecular alignment. Arrhenius plots for the initial rates of photopoly
merization showed a straight line, while those of thermal polymerization ch
anged in slope at the nematic-isotropic phase transition temperature. For M
BEA, the number-average molecular weight of the polymer produced by thermal
polymerization in the nematic phase was higher than that in the isotropic
phase. For ABBA, it was observed that birefringence partially remained in t
he polymer produced in the nematic phase, although polymer produced by solu
tion polymerization showed no liquid-crystalline phase. In addition, the or
ientation of the crosslinked polymer obtained by photopolymerization was be
tter than that of the polymer produced by thermal polymerization. (C) 1999
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