Preparation of a Nano-TiO2-Loaded Antioxidant and Its Anti-aging Performance against UV/O3 in Thermoplastic Vulcanizates

To promote the anti-aging performance of thermoplastic vulcanizates (TPVs) versus ultraviolet (UV)/O3 exposure, a nano-TiO2-loaded antioxidant (TiO2-KH570-MB) was prepared by a thiol–ene reaction between 2-mercaptobenzimidazole (MB) and modified nano-TiO2 (TiO2-KH570). Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis demonstrated the chemical linkage between MB and modified nano-TiO2, and the loading amount of MB was approximately 5.19 wt %. The contact angle test showed that the surface hydrophobicity of TiO2-KH570-MB was significantly increased due to the immobilization of MB. Scanning electron microscopy revealed that TiO2-KH570-MB was uniformly distributed in the TPV matrix. The anti-aging property of TPV compounds was tested in the device with high-intensity ultraviolet radiation and high-concentration ozone. The effects of UV/O3 comprehensive aging on the TPV compounds were evaluated by means of the variations of surface morphology, tensile test, hardness, gel content, and carbonyl index with aging time. On the basis of the aging behavior, we concluded that TPV/TiO2-KH570-MB exhibited excellent stability against UV/O3 aging, due to the homogeneous dispersion, low level of migration, and low volatility of TiO2-KH570-MB.