Durability improvement mechanism of polymer cement protective coating based on functionalized MXene nanosheets modified polyacrylate emulsion

Polymer cement coatings (PCCs) have a wide range of applications in the field of concrete protection. Excellent durability of the PCCs is extremely essential for protecting the concrete in long-time service life. However, one of the most popular polymer emulsion, polyacrylate based cement coatings show insufficient durability and restrict their wide application in complicated and harsh environment. In this study, the novel two-dimensional nanomaterial MXene was incorporated to PCCs for improving the durability of the PCCs, the MXene was functinalized by vinyl triethylsilane (VTEO) (V-MXene) followed by in-situ seed emulsion polymerization method to synthesize the V-MXene modified polyacrylate emulsion. The effects of V-MXene incorporation on the rheological property, mechanical properties, bonding strength, UV aging resistance, saltwater immersion resistance, thermal aging resistance of PCCs were systematically investigated and the durability improvement mechanism was revealed. When the V-MXene dosage is 0.15 wt%, the tensile strength and bonding strength of the PCCs increased by 28.76 % and 30.84 % as compared with the blank samples, respectively. The introduction of V-MXene to PCCs can remarkably improve the UV aging resistance, saltwater immersion resistance, heat resistance. The V-MXene can decrease the UV radiation energy absorbed into the PCCs, and can create a "labyrinth effect", prolonging the penetration path of water and corrosion ions. The V-MXene can also enhance the cross-linking density of the polymer phase combined with organic and inorganic interpenetrating networks, thereby enhancing the thermal stability of PCCs. This research provides a feasible strategy for the fabrication of high performance PCCs with excellent durability.