NOVEL POLY(ETHERAROYL-CO-TEREPHTHAL) HYDRAZIDES WITH LIQUID-CRYSTALLINE BEHAVIOR

Novel poly(etheraroyl-co-terephthal)hydrazides with liquid crystalline (LC) behaviour, synthesized by solution polycondensation followed by non-solvent coagulation in water, have been characterized by means of Fourier Transform infrared (FT-i.r.), differential scanning calorimetr y (DSC) and wide angle X-ray scattering (WAXS) techniques. DSC thermog rams and WAXS intensity profiles of ''as polymerized'' and coagulated homo- and copolymers are strongly dependent upon the molecular structu re and constitution of the polymers: the poly(etheraroyl-hydrazide) ho mopolymer shows an LC behaviour and such a characteristic is maintaine d in copolymers with low content of terephthaloyldichloride comonomer, while a further increase in comonomer content attenuates this LC atti tude. Annealing treatments on ''as polymerized'' and coagulated copoly mers are able to transform the LC phase ''metastable at room temperatu re'' into crystalline and/or amorphous phases.