Fracture toughnesses of bisphenol a type epoxy resin and silica particulate-filled epoxy composite

Abstract

Using Raman spectroscopic analysis and the fractographical analysis, we investigated the relationship between the glass transition temperature, Tg, the fragility parameter, m, and the fracture toughness, Klc, of epoxy resin and composite. Tg and m derived from the thermo-viscoelasticity were used to characterize the epoxy resin and composite post-cured under various conditions. The Raman spectroscopic analysis showed that the Tg is directly related to the degree of cross-linking reaction of the epoxy resin and the matrix of composite. The fractography showed that m of the epoxy resin depends on the heterogeneous microstructure. The m of the composite was dominated by the volume fraction. Klc of the epoxy resin increased as m decreased when the Tg was saturated at approximately 400 K. A composite with a high Tg and a low m had a high Klc value.