Synthesis and properties of novel random copolymers of poly(ether ketone ether ketone ketone)–poly(ether ketone sulfone imide)

Abstract

The monomer containing sulfone and imide linkages, namely bis[4-(p-phenoxybenzoyl)-1,2-benzenedioyl]-N,N,N′,N′-4,4′-diaminodiphenyl sulfone (BPBDADPS), was prepared by the Friedel–Crafts reaction of bis(4-chloroformyl-1,2-benzenedioyl)-N,N,N′,N′-4,4′-diaminodiphenyl sulfone with diphenyl ether. Novel random copolymers of poly(ether ketone ether ketone ketone)–poly(ether ketone sulfone imide) were synthesized by the electrophilic Friedel–Crafts acylation polycondensation of terephthaloyl chloride with a mixture of 4,4′-diphenoxybenzophenone and BPBDADPS in the presence of anhydrous aluminum chloride and N-methylpyrrolidone in 1,2-dichloroethane. The random copolymers with 10–35 mol% BPBDADPS are semicrystalline and had remarkably increased glass transition temperatures (T_g s) over the conventional poly(ether ether ketone) and poly(ether ketone ketone) due to the incorporation of polar sulfone and imide linkages in the main chains. The copolymers IV and V with 30–35 mol% BPBDADPS had not only high T_g s of 184–186°C but also moderate melting temperatures (T _ms) of 336–340°C, having good potential for melt processing. The copolymers IV and V had tensile strengths of 100.8–103.6 MPa, Young’s moduli of 2.31–2.48 GPa, and elongations at break of 10.9–12.4% and exhibited high thermal stability and good resistance to organic solvents.