Effect of nano-TiO2 immobilized antioxidant on ageing resistance behavior of thermoplastic vulcanizate exposed to UV/O3

Nano-TiO 2 immobilized antioxidant (TiO 2 -KH550-AG) was prepared to improve the ageing resistance of thermoplastic vulcanizate (TPV) exposed to UV/O 3 . TiO 2 nanoparticles were firstly modified with 3-aminopropyltriethoxysilane (KH550) and then reacted with the antioxidant , 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid (AG), through the acyl chloride reaction followed by the amidation. FT-IR, XPS and TGA measurements confirmed that the antioxidant (AG) was chemically immobilized onto the nano-TiO 2 surfaces. TPV/TiO 2 -KH550-AG nanocomposites were prepared by melt mixing. SEM observation showed that TiO 2 -KH550-AG was homogeneously dispersed into the matrix of TPV. The UV/O 3 ageing test of the samples was carried out in the environment with constant UV intensity of 1.40 mW/cm 2 and ozone concentration of 100 ± 4 mg/m 3 . The ageing resistance behavior of the TPV/TiO 2 -KH550-AG nanocomposites was evaluated by the changes of surface morphology , mechanical properties and carbonyl index during the UV/O 3 ageing test. It was observed that the TPV/TiO 2 -KH550-AG exhibited high stability during the process of UV/O 3 ageing. The results revealed that the anti-ageing efficiency of TiO 2 -KH550-AG was superior to the mixture of the corresponding AG and modified TiO 2 , owing to the better dispersion and migration resistance of TiO 2 -KH550-AG.