Polyarylates containing phthalazinone moieties with excellent thermal resistance

Polyarylates containing phthalazinone moieties are synthesized by interfacial polymerization of 2,4-(4-hydroxyphenyl)-2,3-phthalazin-1-one with isophthaloyl dichloride (IPC) and terephthaloyl dichloride (TPC). The effects of organic solvents and phase transfer catalysts (PTC) on the intrinsic viscosity (eta( int )) are systematically investigated for polymers with eta( int ) up to 1.52 dL g(-1). The polyarylate has a high eta( int ) with 1,2-dichloroethane and cetyltrimethylammonium bromide used as the organic phase solvent and PTC. It is found that polyarylates prepared from BPPZ with IPC and TPC have excellent thermal resistance, with glass transition temperatures of 292 and 337 degrees C, respectively. The polyarylates exhibit excellent thermal stability with 5% mass-loss temperature above 469 degrees C in both N-2 and air, and residual mass ratios at 800 degrees C in N-2 and air above 54.1% and 4.0%, respectively.