Synthesis and properties of new aromatic-aliphatic homo-and copoly(ester-imide)s based on 3,4,3',4'-diphenylsulphone tetracarboxdiimide

Abstract

New aromrnatic-aliphatic homo-and copoly(ester-imide)s were prepared by the melt polytransesterification of a dihexanol derivative of 3,4,3',4'-diphenylsulphone tetra-carboxdiimide and'/or a dioxydihexanol of biphenyl with aliphatic dimethyl esters of various chain lengths (m=6, 8 and 18) in the presence of zinc acetate. The tetracarboxdiimide derivative was prepared by the methanolysis of the corresponding diacetylated compound derived from 3,4,3',4'-diphenylsulphone tetracarboxylic dianhydride and 6-amino-1-hexanol with acetic anhydride. The structures of the polymers were confirmed by means of FTIR and 13C NMR spectra, and elemental analyses. They had very good solubility in organic solvents such as chloroform and dichloroacetic acid. The thermal properties of the polymers were investigated by differential scanning calorimetry (DSC), and thermogravimetry and differential thermal analysis (TG-DTA) measurements. The thermal analysis data indicated that the polymers were thermally stable up to near 300C in air and had low phase transition temperatures based on glass transition, and melting and/or isotropization below 200C. Two biphenyl-rich copolymers were recognized to show thermotropic liquid crystalline nematic phases by optical texture observation and x-ray analyses at various temperatures.