Investigation of irradiation dose rate on curing characteristics of carbon fiber/polymer composites by low-energy electron beam

During in situ low-energy electron beam (E-Beam) curing for carbon fiber-reinforced polymer composite, prepregs undergoes 3 sequenced curing processes, namely E-Beam-induced curing, postray curing after irradiation, and thermally induced curing. In this study, the irradiation dose rate (IDR) is demonstrated to be influential on the redistribution of the curing portions in the 3 curing stages and directly influences the interlaminar bonding quality of the stepwise cured laminates. Differential scanning calorimetry results showed that higher IDR resulted in higher temperature of irradiated prepregs, and hence, a higher degree of curing was induced by the E-Beam within a dose range of 0 to 500 kGy as compared to lower IDRs, which decreased the interlaminar physical adhesive quality between layers. Analysis indicates that other than pure physical adhesion between uncured layers, postray curing can further enhance the interlaminar shear strength for cured laminates by introducing cross-layer chemical bonding in the interlaminar zone.