High Molecular Weight Polyphenylquinoxalines with Increased Solvent Resistance

摘要

Biphenyl-based bisbenzilmonomers which contain pendant phenylethynyl groups in the 2,2' positions are condensed with 3,3'- diaminobenzidine to make polyphenylquinoxalines (PPQS). Thermal cure of these polymers cause an intramolecular cyclization (TMC) of the phenylethynyl groups to give the rigid 9-phenyldibenzathracene system in the backbone of the polymer. The initial, uncured polymers form tough films which are soluble in m-cresol and chlorinated solvents, but after thermal cure the films become insoluble in all common organic solvents and acids while maintaining their toughness. DSC scans of the cured materials showed small residual exotherms indicating that after vitrification even the intramolecular rotation required for the IMC reaction becomes restricted. Keywords Thermoplastic matrix resins, Solvent resistant thermoplastics. (aw)