Polybenzoxazoles were successfully prepared from bisaminophenols based upon 4,4'-isopropylidene diphenol (bisphenol A) and terephthaloyl chloride and optionally isophthaloyl chloride monomers. The successful 'one-pot' process involves a low-temperature polycondensation followed by an acid-catalysed solution cyclization reaction. The fully cyclized copolymers were isotropic in nature, displayed glass transition temperatures as high as 300°C, and formed tough films when prepared from m-cresol. Semicrystallinity could be developed in the 100% terephthaloyl chloride polybenzoxazole (PBO) system when annealed 40°C above its T r Characterization of the fully cyclized materials was demonstrated via the aid of spectroscopic and solution characterization techniques. The process is also amenable to higher-performance PBO systems
Посилання на статтю:
Synthesis of 4,4'-isopropylidene diphenol (bisphenol A) based polybenzoxazoles via an acid-catalysed solution cyclization process* / W. D. Joseph, R. Mercier, A. Prasad, H. Marand and J. E. McGrath // Polymer. – 1993. – Vol 34. – P. 866-869.