Effects of Silicon Dioxide/Graphene Oxide Hybrid Modification on Curing Kinetics of Epoxy Resin

In this study, SiO2-grafted graphene oxide (GO-SiO2) was prepared using the oxygen-containing group on the GO surface as the active site of the reaction. The chemical structure, morphology, and particle size of GO and GO-SiO2 were carefully investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetry, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy, and the results proved that the grafting modification was successful. Furthermore, epoxy (EP)/GO composites were prepared, and the effects of unmodified GO and GO-SiO2 on the curing kinetics of EP were comparatively studied by differential scanning calorimetry (DSC). The results showed that, compared with neat EP and EP/GO, GO-SiO2 significantly reduces the curing temperature of the composites, indicating that GO-SiO2 has a more significant catalytic effect on the curing process of EP. The calculation results of the Kissinger method showed that the curing activation energy of EP/GO-SiO2 is obviously lower than that of EP/GO and neat EP. Results of the Ozawa method showed that the introduction of GO-SiO2 reduces the curing activation energy during the whole curing process, and in the middle and late stages of curing (α = 0.5-1) can significantly reduce the curing activation energy. The related mechanism has been proposed.