Epoxy-ended hyperbranched polymer-grafted graphene oxide for cold-mixed epoxy asphalt modification

To improve the compatibility of asphalt-epoxy and mechanical properties of cold-mixed epoxy asphalt (CEA), epoxy-ended hyperbranched polymer (EHBP) was grafted on the surface of graphene oxide (GO) nanoplates to synthesize GOEHBP as a compatilizer. The chemical structures and micromorphology of GOEHBP were analysed through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermo gravimetric analysis and transmission electron microscopy. The CEA modified by EHBP and GOEHBP was investigated by tensile test, dynamic thermomechanical analysis, viscosity test, fluorescence microscope experiment, FTIR analysis and XPS analysis. The results showed that the EHBP was successfully grafted onto the surface of GO via chemical reaction, and the GO was partially reduced. The mechanical properties of CEA modified by EHBP are obviously improved, and the elongation at break was increased by 74.5%. The glass transition temperature of CEA modified by GOEHBP was increased to 62.58°C. At high temperature (≥40°C), the E′ of CEA modified by GOEHBP was larger than that of the CEA, indicating that GOEHBP can improve the high-temperature deformation resistance of CEA. The addition of GOEHBP can improve the compatibility of asphalt-epoxy, thus improving the toughness of CEA.