Light stabilizers added to the shell of coextruded wood-high density polyethylene composites to improve mechanical and anti-UV aging properties

Weathering of wood-plastic composite (WPC) leads to discoloration and cracks, which greatly limits its outdoor application. In this study, light stabilizers (including UV-327, HS-944, and Nano-SiO2) were added to the shell of coextruded high-density polyethylene (HDPE) based WPC to improve its anti-ultraviolet (UV) aging property and simultaneously to maintain its good mechanical property. The obtained results showed that the UV-327 was the most effective light stabilizer on improving the mechanical and anti-UV aging properties of the composites among the three stabilizers used. WPC samples added with 2% UV-327 had the highest retention rates in flexural strength and also had the smoothest surface after 2500h of UV aging. The samples added with 2% UV-327 had the best protection for the discoloration, showing the lowest values of ΔE (color difference) and ΔL (luminescence) in all samples after 2500h of UV aging. WPC added with 2% UV-327 was oxidized to the slightest extent after 2500h of...