Improvement of UV aging resistance of PBAT composites with silica-immobilized UV absorber prepared by a facile method

Prolonging the service life of polymer materials by enhancing their aging resistance is an effective and practical way to reduce the polymer waste. In this work, to improve the migration resistance and thermal stability of commercial UV absorber used in polymer composites, a solvent & coupling agent-free method with only one-step reaction was proposed to immobilize a commercial UV absorber 2‑hydroxy-4-(octyloxy)benzophenone (UV-531) onto the surface of silica nano particles (SiO2). UV-531 was chemically bonded on the surface of SiO2 with the loading weight of 12%. The as-prepared immobilized UV-531 (SiO2–531) could be homogeneously dispersed in the matrix of poly(butylene adipate-co-terephthalate) (PBAT) and showed significantly improved migration resistance and thermal stability compared with free UV-531. For example, the initial decomposition temperature of SiO2–531 is about 200 °C higher than that of free UV-531. Therefore, PBAT/SiO2–531 composites showed even better anti-UV aging performance than PBAT/SiO2 composites with twofold added free UV-531 during accelerated ultraviolet weathering and long-term natural climatic aging tests. For example, PBAT/SiO2–531 composites can maintain higher retentions of tensile strength and elongation at break than PBAT/SiO2 composites with free UV-531 does after accelerated UV aging. Hopefully, the proposed facile method to enhance the anti-UV aging efficiency of commercial UV absorber may potentially uncover an extensive family of building blocks for constructing highly anti-aging plastic composites.