Effect of accelerated weathering on color and physico-mechanical properties of wood-plastic composites with nano titanium dioxide

Polypropylene (PP) with black locust wood flour and maleic grafted polypropylene were used to prepare wood plastic composites (WPC) by injection molding. The effect of the addition of nano titanium oxide (nano TiO2) on the properties of the composites was investigated. The specimens were weathered in an accelerated weathering apparatus using a xenon arc lamp for 2000 h. The physical properties of the composites were evaluated by colorimetry, water absorption, and thickness swelling before and after weathering. Mechanical properties of WPC were also determined before and after weathering. The WPC containing 0.75 phr nano TiO2 showed an improvement in the flexural and tensile strength and flexural and tensile modulus while the WPCs containing 0.2 phr nano TiO2 showed an improvement in the impact strength. The UV resistance of the WPCs also improved with the incorporation of nano TiO2 powder into the composites. Both water absorption and thickness swelling were found to be reduced by the incorporation of nano TiO2 into WPC.