Synthesis and preliminary characterization of a new fully aromatic mesogenic polyester containing a 2-phenylbenzoxazole group

The synthesis of a new thermotropic polyester obtained by reaction of terephthalic acid and 2-[4-(acetyloxy)phenyl]-6-(acetyloxy)benzoxazole is described. The polymer as prepared is a semicrystalline material, with a T g of 181°C, that melts at 408°C to give a liquid crystal phase of probable nematic nature. Relevant chemical decomposition takes place in the temperature range 510-620°C. A remarkable crystallinity was observed also in samples obtained by cooling the liquid crystal phase. Fibers were obtained by melt extrusion which show a high degree of macroscopic orientation