Preparation of weather-resistant and heat-resistant waterborne acrylic coatings in high-temperature and high-humidity environments

This study aims to enhance the dispersion of SiO₂ aerogel in the coating and improve its overall performance.

The SiO₂ aerogel was modified by silane coupling agent KH550 in this study. The successful surface modification was confirmed by fourier transform infrared spectroscopy(FTIR) analyses. The optimization effect of different modified SiO₂ (M-SiO₂) aerogel contents on the comprehensive performance of the waterborne acrylic coating was studied by resistance to liquid medium tests, aging resistance test, adhesion tests, thermal insulation tests, immersion corrosion tests and salt spray tests.

The results demonstrated that KH550 effectively enhanced the compatibility between SiO₂ aerogel and the coating, reduced agglomeration and significantly improved the thermal insulation performance and corrosion protection of the coating. When the M-SiO₂ aerogel content was 0.8 Wt.%, the adhesion rating remained at level 0 and the coating exhibited superior resistance to alkaline and aqueous environments, with color difference values of 0.47 and 0.94, respectively. After seven days of xenon lamp aging, the color difference was only 2.64. The thermal insulation temperature difference reached 17.28°C after 40 min. In addition, after immersion in a 3.5 Wt.% NaCl solution for 336 h, the coating exhibited an impedance value of 3.85 × 10⁵ Ω·cm². Following a seven-day salt spray test, no corrosion traces were observed on the coating surface, with an impedance value of 3.15 × 10⁵ Ω·cm².

This study provided a theoretical basis for the development of high-performance composite coatings with enhanced weather resistance and thermal insulation properties.