THERMOPLASTIC-TOUGHENED EPOXY POLYMERS

The microstructure and properties of two epoxy-resin systems which hav e been modified with varying amounts of a thermoplastic to improve the toughness of the thermosetting epoxy polymers, have been studied. The curing agent was 4,4'-diaminodiphenylsulphone and the thermoplastic w as a reactively terminated poly(ether sulphone) copolymer. Different m icrostructures were found to occur as the concentration of the thermop lastic component was steadily increased. In particular, the relationsh ips between the microstructures and values of stress-intensity factor, K(Ic), and fracture energy, G(Ic) were explored.