Effect of surface modified nano-SiO2 particles on properties of TO@CA/SR self-healing anti-corrosion composite coating

At present, microcapsule technology can carry out intelligent self-healing for micro-cracks, so as to prolong the service life of the marine protective coating. However, after adding microcapsules, the properties of the coating itself, such as coating adhesion, distinctness of image, and mechanical properties, will be affected to a certain extent. In this paper, calcium alginate containing tung oil self-healing microcapsules (TO@CA) is dispersed in silicone rubber (SR) coating (TO@CA/SR) and the related properties of TO@CA/SR are tested. TO@CA/SR coating prepared with TO@CA average size of 63.84 μm and the content of 10% (T-63-10%) has the optimal performance. At the same time, TO@CA/SR composite coating is enhanced and modified by filling inorganic nano-SiO 2 to realize self-healing microcracks without affecting the mechanical properties. TO@CA with modified nano-SiO 2 of 2% (T/SiO 2 -2%) has the best self-healing, corrosion resistance, and mechanical properties. It shows that Nano-SiO 2 forms a 3D connected network with SR and a double network structure coupled with the silicon chain network. The reversible bonding between nano-SiO 2 and SR or nano-SiO 2 dissipates the mechanical energy effectively under external force, thus improving the mechanical properties of coating. This study is of great significance for offset the impact of the microcapsules on the mechanical properties of the coating as much as possible, so as to ensure good stability of the self-healing coating. • The synergistic mechanism of TO@CA and nano-SiO 2 is analyzed to improve the corrosion resistance and protection performance.