▎ 摘　　要

The incorporation of graphene oxide (GO) into waterborne polyurethane (WPU) coating shows great potential in enhancing the performance of WPU coating. But homogeneous dispersion of GO in polymer matrix is still a challenge for the application of GO. In this paper, the polyacrylic acid modified graphene oxide (PAA-nGO) with high dispersion stability in a wide range of pH (4-11) was prepared via two step amidation reaction. Significantly, PAA-nGO can be uniformly dispersed in WPU as bifunctional additive to prepare WPU/PAA-nGO coatings with enhanced mechanical property, chemical resistance and abrasion durability. The as-prepared WPU/PAA-nGO coating exhibited improved tensile strength (18.12 MPa) and tear strength (38.07 kN/m), which were 56.1% and 51.5% higher than those of pure WPU coating, respectively. Interestingly, WPU/PAA-nGO coating showed improved chemical resistance. Notably, abrasion durability of WPU/PAA-nGO coating was significantly enhanced, and the mass loss rate was decreased by 77.1%. Overall, this work provided a potential strategy for improving the mechanical property, chemical resistance and abrasion durability of WPU based coatings by introducing PAA-nGO with well dispersion and high stable in a wide pH range.