SYNTHESIS AND CHARACTERIZATION OF NOVEL TOUGHENED THERMOSETS DERIVED FROM PENDENT AMINES ON THE BACKBONE OF POLY(ARYLENE ETHER SULPHONE)S

Random incorporation of pendent aryl amines on the backbone of poly(arylene ether sulphone)s was achieved by the copolymerization of a minor amount of a second activated aromatic dihalide, bis(4-fluorophenyl)-3-aminophenylphosphine oxide (amino DFTPPO), with 4,4'-dichlorodiphenylsulphone (DCDPS) and bisphenol A via aromatic nucleophilic substitution polymerization using N-methylpyrrolidone (NMP) as the solvent, toluene as the azeotroping agent and potassium carbonate as the base. The pendent amines were optionally chemically modified by conversion to maleimides and thermally cured to afford tough insoluble networks. Epoxy networks were also obtained by reacting the pendent amines with liquid epoxy resin and 4,4'-diaminodiphenylsulphone (DDS). The synthesis and characterization of these novel thermosetting materials were investigated, and it was demonstrated that selected compositions could significantly improve the fracture toughness of the epoxy networks. Two important variables identified were the weight or volume fraction of the thermoplastic modifier and, importantly, the concentration of the pendent aminophenyl 'cure' sites. In this research, about 2.5 mol% cure sites was the optimum concentration utilized, which produced tough multiphase systems. Higher aminophenyl concentrations resulted in more homogeneous morphologies and fracture toughness was about the same as the control.