Fracture Behaviour of Thermoplastic Modified Epoxy Resins

Abstract This work has shown that the addition of polyetherimide (PEI) can significantly increase the toughness of highly cross-linked epoxy resins, whilst retaining a high Tg and modulus. These combined properties indicate the potential of PEI modified epoxy resins for use as matrices for advanced composite materials. In terms of GIC, addition of 20wt% PEI raised the toughness by a factor of eight. Evidence from SEM fracture surfaces suggests that the toughening mechanism operating in bulk PEI modified epoxy resin is ductile drawing of the PEI. Carbon fibre composites based on 30wt% PEI modified epoxy resin matrices show considerable improvement in toughness at low and high strain rates when compared with CFRP possessing unmodified or 20wt% modified PEI content epoxy resins.