The effect of semi-curing on neat resin mode I fracture properties

The sensitivity of fracture toughness to the cure path of a high-performance hot infusion epoxy resin (EP2410) is assessed in this study through single-edge notch bend testing of neat resin specimens. The specimens were prepared using a two-stage semi-curing process. In the initial stage, the partial degree of cure and the semi-cure temperature were varied. In the second stage, samples were heated to 180 °C for a secondary post-cure. These samples were compared to two baseline samples produced using the manufacturer's recommended cure cycle of 180 °C, and a modified isothermal cure at a lower cure temperature of 140 °C. The results show that the semi-curing path has no statistically significant influence on the mode I fracture toughness of the material studied here. Sample similarity was confirmed through SEM examination of the fracture surface, which showed minimal variation in surface topography. These findings open new possibilities to use this type of material for novel manufacturing processes involving semi-curing steps.