Fracture toughness of difunctional epoxy resin/thermally latent initiator system modified with polyesters

Aromatic polyester was used as a modifier to improve the toughness of diglycidylether of bisphenol A (DGEBA)/thermally latent initiator system. N-Benzylquinoxalinium hexafluoroantimonate (BQH) was used as a thermally latent initiator for thermal curing, and the content of polyester was varied from 2.5 to 10 wt%. The thermal latent behaviors, thermal properties, and mechanical interfacial properties of DGEBA/ polyester blends were investigated with several techniques. It was found that the BQH as a latent initiator showed the activity at a comparably narrow temperature range in the present study. The K _IC of the DGEBA/polyester blends was higher than that of the neat epoxy system and exhibited a maximum value at 5 wt% polyester. The scanning electron microscope (SEM) results showed rough and plastic deformation morphologies in the DGEBA/polyester blends.