TiO2-loaded Halloysite Nanocomposites: Achieving the UV Resistance and Dielectric Stability of Polyurea

This study proposes a modification strategy for polyurea (PU) using halloysite nanotubes (HNTs) loaded with titanium dioxide (TiO 2 ) to enhance the ultraviolet (UV) aging resistance of PU materials. TiO 2 –HNT nanocomposite fillers were prepared through the surface loading modification, and the effects of different TiO 2 –HNT concentrations (2–10 wt%) on the structural, hydrophobic, and dielectric properties of PU composites were systematically investigated. Through the analysis of the test results, we discovered an interesting phenomenon: the UV shielding performance of the nanocomposite enhances the UV resistance of PU at low content levels, whereas at high content levels, the photocatalytic effect of TiO 2 accelerates PU degradation. With 4 wt% TiO 2 –HNT loading, PU exhibited the best stability and achieved a 76.4% enhancement in dielectric constant while maintaining hydrophobicity (contact angle >110°). After 300 h of accelerated UV aging, the optimized PU retained 83.9% of its initial breakdown strength, outperforming pure PU (76.1% retention), and its dielectric loss was 25.8% lower than that of pure PU. The developed nanocomposite offers a green and efficient solution for enhancing the durability and stability of insulation materials in high-voltage transmission systems.