A NOVEL SIDE-CHAIN LIQUID-CRYSTALLINE POLYURETHANE

Side chain liquid crystalline polyurethanes (SCLP) without flexible sp acer were synthesized by a two step block copolymerization reaction. T he polyurethanes were based on azobenzene-type mesogenic diol chain ex tender (DR-19), a poly(tetramethylene oxide) (PTMO) soft segment, and different diisocyanates, including 4,4-diphenylmethane diisocyanate (M DI) and hexamethylene diisocyanate (HDI). The polyurethane samples obt ained from DR-19 or DR-19(.) and PTMO with HDI had mesomorphic phases as determined by DSC and polarizing microscopy.