Fracture Properties of Bisphenol A Type Epoxy Resin Mixed with Different Monomers: Considered in Term of Material Characterization

摘要

In the present study, we investigated the effect of adding a high molecular weight monomer to one with low molecular weight on the fracture toughness of epoxy resin in terms of cross-link density and heterogeneity. To characterize the cross-link density and heterogeneity; we evaluated the glass transition temperature, T_g, and fragility, m, from thermo-viscoelastic properties. To confirm the micrestructure heterogeneity in the epoxy resins, we analyzed roughness of fracture surfaces with atomic force microscope. Over the range from 0 to 30 wt% high molecular weight monomer used in the present work, we found that it induced lower cross-link density (lower T_g) and made epoxy resin more heterogeneous (lower m), and this resulted in higher K_(IC). This study revealed that both T_g and m are effective for characterizing material in relation to the fracture toughness of the blended epoxy resins.