A novel synthesis method for the preparation of aromatic poly(imide benzoxazole) from trimellitic anhydride chloride and bis(o-aminophenol)

Abstract

A poly(imide benzoxazole) was prepared directly from trimellitic anhydride chloride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (BisAPAF) monomers in a two-step method. In the first step, a poly(hydroxyamide amic acid) precursor was synthesized by the low-temperature solution polymerization in an organic solvent. Subsequently, thermal cyclodehydration of the poly(hydroxyamide amic acid) precursor at 350°C produced the corresponding poly(imide benzoxazole). The inherent viscosity of the precursor polymer was 0.22 dL/g. The cyclized poly(imide benzoxazole) showed a glass transition temperature (Tg) at 329°C and a 5% weight loss temperature at 530°C in nitrogen and at 525°C in air. The poly(imide benzoxazole) is amorphous as evidenced by the wide-angle X-ray diffraction measurement. The structures of the precursor polymer and the fully cyclized polymer were characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance spectroscopy (1H NMR). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2388–2391, 2003