Crosslinking liquid crystalline polyesters with allyl group as lateral substituent: thermal and UV activation

The synthesis of networks from liquid crystalline polyesters bearing allyl groups as lateral substituents is reported. Crosslinking is performed both by thermally activated radical reaction and by UV irradiation of film sampl es containing the suitable activator. Moreover, fibrous samples have been c rosslinked in the solid state by UV irradiation, "quenching" the nematic or ganisation on a macroscopic scale and resulting in a macro-oriented network . Crosslinking does not hamper molecular mobility. As a consequence, the de gree of orientation and the length of crosslinked fibres change continuousl y and reversibly upon heating and cooling through the isotropisation transi tion. (C) 2000 Elsevier Science Ltd. All rights reserved.