STUDIES ON THE THERMOTROPIC LIQUID-CRYSTALLINE POLYMER .8. SYNTHESIS AND PROPERTIES OF FULLY AROMATIC POLY(ESTER)S AND POLY(AMIDE-ESTER)S CONTAINING P-PHENYLENE DIACRYLIC GROUP

Three series of polymers containing p -phenylene diacrylic group were prepared by direct polycondensation in the presence of diphenylchlorophosphate and pyridine. Series I was prepared from p -phenylene bis (acrylic acid) with various hydroquinones. Series II was prepared from p -phenylene bis (beta-cyano acrylic acid) with methylhydroquinone. Series III was prepared from 3-methyl-4-aminophenol with p-phenylene bis(acrylic acid) or p-phenylene bis (beta-cyano acrylic acid), respectively. The phase behavior of these polymers was studied by differential scanning calorimetry (DSC), optical polarizing microscopy equipped with a heating stage, and wide-angle x-ray diffraction (WAXD). It was found that these polymers, except IIIb, exhibit thermotropic liquid-crystalline properties and show threaded or Schlieren texture under the optical polarizing microscopic observation. Furthermore, the melting temperatures of these polymers were decreased in the range of 254-354-degrees-C by incorporating with p-phenylene diacrylic group into the main chain.