Nickel-catalyzed in situ synthesis of UHMWPE/TiO2 composites with enhanced mechanical properties and adjustable photocatalytic degradabilities

Expanding the application field of polyolefin materials through functionalization has been a research hotspot in the past three decades. Here, a TiO₂-supported anilinenaphthoquinone nickel catalyst was assembled and applied for in situ ethylene polymerization with high activity (>2000 kg mol^–1h⁻¹) to produce ultra-high molecular weight polyethylene (UHMWPE)/TiO₂ composites with unique physicochemical performance. The UHMWPE/TiO₂ composite films and fibers prepared by in-situ ethylene polymerization are superior to the samples from the blend system in issues such as TiO₂ dispersibility, mechanical property, and photocatalytic degradability. The mechanical properties (strength up to 26.8 cN/dtex, modulus up to 1248.8 cN/dtex) of the obtained UHMWPE/TiO₂ composite fibers are significantly improved with a very low dosage of TiO₂ (as low as 1.4 wt‰). Moreover, UHMWPE/TiO₂ composites obtained by coating Al₂O₃ and SiO₂ on the surface of TiO₂ not only retain the strong absorption of ultraviolet rays, but also effectively weaken the photocatalytic degradation effect.