▎ 摘 要
This work revealed the influences of graphene oxide (GO) sheet size on the curing kinetics and thermal stability of epoxy resins. A series of GO/epoxy nanocomposites were prepared by the incorporation of three different sized GO sheets, namely GO-1, GO-2 and GO-3, the average size of which was 10.79 mu m, 1.72 mu m and 0.70 mu m, respectively. The morphologies of the nanocomposites were observed by field emission gun scanning electron microscope. The dispersion quality of each sized GO was comparable in the epoxy matrix. The curing kinetics was investigated by means of differential scanning calorimetry and analyzed based on kinetics model. Addition of a small amount of GO (0.1 wt%) exhibited strong catalytic effect on the curing reaction of epoxy resin. The activation energy was reduced by 18.9%, 28.8% and 14.6% with addition of GO-1, GO-2 and GO-3, respectively. GO-2 with medium size (1.72 mu m) showed the most effective catalysis on the cure. The thermal stability of the cured resins was evaluated based on thermogravimetric analysis. GO/epoxy nanocomposites showed improved thermal stability in the range of 420 degrees C-500 degrees C, compared with the pure resin. A similar to 4% more residue was obtained in each of the incorporated system. The variations of GO sheet size did not influence the enhancement effect on the thermal stability.