Thermal stability of some polyquinazolone polymers: Effect of acid catalysis

Abstract

Thermal properties of polyquinazolones (PQ) polymers prepared from 4,4′-diaminodiphenyl-3,3′-dicarboxylic acid (BDC) and 4,6-diamino-isophthalic acid (DAIA) with diacetamido derivative of a number of diammines have been studied by thermogravimetry (TG) and differential scanning calorimetry (DSC). The effect of acid catalysis was also investigated. The results show that polyquinazolones prepared from DAIA have higher thermal stabilities and glass transition temperatures compared to those prepared from BDC. This can be attributed to the more stable and rigid fused quinazolone backbone unit in the PQ/DAIA system. Both polymer systems show improved thermal stability in the presence of catalyst which is a direct result of increased number of fully cyclised quinazolone rings in the polymer. © 1987 Wiley Heyden Ltd., Chichester and Akadémiai Kiadó, Budapest.