Preparation Of Imidazole-functionalized Graphene Oxide And The Application In Epoxy Resin

Graphene have received much attention owing to its excellent physical and chemical properties. But poor dispersion of graphene in polymer matrix limits its application in polymer-based nanocomposites. Graphene oxide(GO) is more compatible with polymer matrices than graphene due to the existence of carbonyl, hydroxyland epoxide groups on the material. Besides, graphene oxide can get new function by chemical modification.we try to functionalize GO to cure epoxy resin or catalyze the curing reaction.In this way, functionalize GO can be nano-reinforcement and co-curing agent or catalyst for epoxy resin. In this work, an imidazole-functionalized GO was prepared by the reaction between imidazole and GO. Then we studied the applications of functionalized GO in epoxy resin. Main results are shown as follow:(1) Graphene oxide was prepared using modified Hummers method starting from graphite. Then we prepared amino--functionalized GO(GO-NH2) using sodium azide by Curtius rearrangement.GO-NH2 was examined by FTIR、XPS and UV-visible spectroscopy.(2)Using isophorone diisocyanate as a bridge to make imidazole grafted onto the surface of GO, We prepared imidazole-functionalized GO(GO-IPDI-MZ) successfully. GO-IPDI-MZ had been proven to be effective curing agent for epoxy resin by DSC. Then, we used GO-IPDI-MZ as co-curing agent to prepare GO-IPDI-MZ/epoxy resin composites. When the content of GO-IPDI-MZ was 1wt%, the tensile strength、flexible strength and impact strength reached the maximum.(3) We prepared 2-ethyl-4-methyl imidazole-functionalized GO(GO-IPDI-EMI) successfully using isophorone diisocyanate as a bridge to make 2-ethyl-4-methyl imidazole grafted onto the surface of GO.GO-IPDI-EMI had been proven to be effective catalyst for the curing reaction of dicyandiamide-epoxy resin system and Anhydrides-epoxy resin system. For dicyandiamide-epoxy resin system, the temperature of the curing reaction exhibited a decrease of 25℃ for 1wt% GO-IPDI-EMI loading as compared with the neat dicyandiamide-epoxy resin system. For Anhydrides-epoxy resin system, With 1.0wt%GO-IPDI-EMI, The exothermic peak corresponding to the curing reaction appears at 181℃. We studied the curing reaction mechanisms with the existence of GO-IPDI-EMI for Anhydrides-epoxy resin system.