SYNTHESIS AND CHARACTERIZATION OF POLY(BENZAZOLES) CONTAINING THE BICYCLO[2.2.2]OCTANE MOIETY

Poly(benzobisoxazoles) (PBOs), poly(benzobisthiazoles) (PBTs) and copo lymers thereof containing the a,5-dihydroxybicyclo [2.2.2]octane moiet y have been prepared and studied. The homopolymers were synthesized by the polycondensation of 2,5-dihydroxybicyclo [2.2.2]octane-1,4-dicarb oxylic acid with 4,6-diamino-1,3-benzenediol dihydrochloride or 2,5-di amino-1,4-benzenedithiol dihydrochloride in poly(phosphoric acid). Ran dom and block copolymers (PBO-PBT) were also prepared. The polymers we re characterized by solubility, X-ray diffraction, spectroscopy (infra red and solid-state C-13 nuclear magnetic resonance), and thermal anal ysis such as differential scanning calorimetry and thermogravimetric a nalysis. Thermogravimetric analysis showed thermal stability of the po lymers above 375 degrees C in air and under argon atmosphere. The poly mers exhibited high resistance to organic and inorganic solvents. The polymers were converted to the more stable aromatic polymers via dehyd ration and retro Diels-Alder reactions of the a,5-dihydroxybicyclo [2. 2.2]octyl moiety by pyrolysis. (C) 1998 John Wiley & Sons, Inc.