Hyperbranched graphene oxide structure-based epoxy nanocomposite with simultaneous enhanced mechanical properties, thermal conductivity, and superior electrical insulation

The combination of graphene oxide (GO) nanosheets and polymer matrix provides an opportunity to synthesize polymer composites with excellent engineering application performance. However, the preparation of highperformance GO-based composites is difficult because the nano-scaled GO is easily agglomerated, and the weak interface bonding force between the GO and polymer. Herein, a simple and effective method for preparing GO-based composites via hyperbranched polymer (HPB) grafting is presented. The resulting HPB-GO has uniformly dispersed in the epoxy resin (EP) matrix and combines with the matrix through chemical bonds, which has a strong interfacial acting force and improves the load transfer efficiency of the matrix to HPB-GO. Thus, the resultant EP/HPB-GO nanocomposite exhibited superior mechanical properties with a dramatic increase with only 0.2 wt% HPB-GO loading, the impact strength, the tensile strength, and the compression strength, i.e., 58.53%, 83.29%, and 57%, respectively, when compared to pure epoxy resin. Meanwhile, the nanocomposite exhibits an 80% increase in thermal conductivity (0.32 W m(-1) K-1). Moreover, outstanding electrical insulation performance is obtained. The ultra-low content of HPB-GO significantly improves the performance of epoxy resin, which provides an economical and effective method to broaden the application of epoxy resin in engineering.