SYNTHESIS OF HYBRID LIQUID-CRYSTALLINE BLOCK-COPOLYMERS BY COMBINATION OF CATIONIC OR PROMOTED CATIONIC AND FREE-RADICAL POLYMERIZATIONS

The synthesis of two new classes of liquid crystalline block copolymer s (1-5) by a two-step combination of cationic and free-radical polymer izations is described. An azomacroinitiator was prepared first by cati onic polymerization of tetrahydrofuran or promoted cationic polymeriza tion of cyclohexene oxide, which was then used to initiate the free-ra dical polymerization of an acrylate monomer containing a variously sub stituted biphenyl mesogenic group. The semicrystalline and liquid crys talline blocks were essentially microphase-separated and gave rise to different thermotropic mesophases.