Effect of nano zinc oxide as UV stabilizer on the weathering performance of wood-polyethylene composite

In this study, the effect of using nano-sized zinc oxide (ZnO) particles on the enhancement if the degradation resistance of wood-high density polyethylene (HDPE) composite was investigated through artificial weathering. Samples with different amounts of ZnO mixing ratio (0, 1, 2, and 4 wt%) were manufactured using an internal mixer followed by compression molding. The prepared samples were then exposed to the artificial weathering process in a QUV weatherometer. The weathering behavior of samples was characterized using tensile strength, contact angle analysis, colorimetry, ATR-FTIR spectroscopy and FE-SEM. The results indicated that the amount of surfaces crack, tensile strength loss and contact angle changes decreased as a function of ZnO addition, while lightness changes were not affected. Analysis of the functional groups at the composite surface by ATR-FTIR showed that the incorporation of nano-sized ZnO particles in the composite formulation changed the degradation mechanism of composite to photocatalytic reactions, leading to the production of high levels of zinc carboxylate in the structure of weathered composite.