Effect of pendent phenyl and bis-phthalazinone moieties on the properties of N-heterocyclic poly(aryl ether ketone ketone)s

Abstract A series of novel N-heterocyclic copoly (aryl ether ketone ketone)s containing pendent phenyl groups and bis-phthalazinone moieties (P-BNP) with high molecular weight were successfully synthesized via solution condensation from 4-(3′-phenyl-4′-hydroxyphenyl)-2,3-phthalazin-1-one, 4,4′-di(4′-1(2H)-phthalazinone)-1,1′-biphenyl and 1,4-bis(4′-fluorobenzoyl)benzene. The properties of P-BNPs were identified by thermogravimetric analysis (TGA), differential scanning calorimetry analysis (DSC), and dynamic thermomechanical analysis (DMA) etc. The polymer exhibits excellent thermo-stability in both nitrogen and air. The glass-transition temperature (Tg) is in the range of 240–290 °C, copolymers performing a presentable thermo-resistance. Moreover, copolymers can be dissolved in chloroform and N-methyl-2-pyrrolidone (NMP), exhibiting excellent film-forming property. Simultaneously, copolymers possess favorable mechanical properties. The introduction of pendent phenyl moieties enhances the mobility of molecular chains and solubility of copolymers. The introduction of rigid bis-phthalazinone units enhances the thermo-resistance and mechanical properties of copolymers. Rational allocation of rigid units and side groups content will optimize the comprehensive properties of high-performance polymers.