Synthesis and phase behavior of novel poly(urethane-urea)s based on 44'-bis(2-hydroxyethoxy)biphenyl 24-tolylene di-isocyanate and poly(oxypropylene)diamines

摘要

Novel liquid crystalline poly(urethane-urea)s (PUUs) were synthesized from 2,4-tolylene diisocyanate, 4,4'-bis(2- hydroxyethoxy)biphenyl and poly(oxypropylene)diamines (Jeffamine). The poly(urethane-urea)s were characterized by FTIR, GPC, DSC and polarizing microscopy. The mesomorphic properties of the polymers were investigated as a function of their molecular structure by changing alternatively the molecular weight of Jeffamine or the initial diol and diamine composition. The applied structural modifications allowed us to obtain thermotropic PUUs exhibiting mesomorphic behavior in a wide temperature range along with the PU exhibiting no liquid crystallinity.