Polymerization of <i>p</i>‐methacrylyloxybenzoic acid in mesomorphic and in liquid states

Abstract

Abstract The polymerization of p ‐methacrylyloxybenzoic acid in the liquid crystalline state (dissolved in p ‐cetyloxybenzoic acid) and in the liquid state (solution in dimethylformamide) was studied. The polymerization of p ‐methacrylyloxybenzoic acid in the liquid phase is characterized by regularities usual in the radical homogeneous polymerization of vinyl monomers in isotropic mediums. At temperatures above 100°C. incomplete conversion is observed, which is explained by polymerization–depolymerization equilibrium. The polymerization of p ‐methacrylyloxybenzoic acid in the liquid crystalline phase is characterized by a considerable increase in polymerization rate and polymer molecular weight ( M w = 6 × 10 5 ) over the liquid‐phase polymerization in DMFA ( M w = 5 × 10 4 ). The polymerization rate in liquid crystalline state does not depend on conversion degree and remains constant up to 70–75% conversion. The rate of polymer formation depends only slightly on the initial monomer concentration at the change of [ M 0 ] from 1.3 to 3 moles/l. The molecular structure of the mesomorphic phase also creates favorable thermodynamic conditions for the formation of macromolecules. At all T &lt; T ceiling practically complete conversion of monomer into polymer is observed, which is impossible with homogeneous polymerization in solution.