The Effect of Methylation and Anti-Oxidant on Discoloration of Weathered Wood Plastic Composites

As the outdoor application of Wood Plastic Composites (WPCs) become more widespread، the resistance of these products against weathering، particularly ultraviolet (UV) light becomes more important. When WPCs are exposed to outdoor ultraviolet light، rain، snow and atmosphere pollution، they will be degraded which can be indicated by color fade. To investigate the effects of methylation and Anti-Oxidant separately and together on discoloration of weathered wood plastic composites، composites of poplar wood flour and high density polyethylene. Were made according to the ASTMD 2565، samples were placed in Atlas Xenon apparatus for 250 and 2000 hours. Discoloration and FT-IR spectra of the samples were measured and compared. The results have shown that methylation in short term and long term can relatively reduce the discoloration of weathered samples and also in short term can hinder the photodegradation. FT-IR spectra showed that، in long term، neither of the treatments could protect lignin from irradiation within wood flour. But methylation limited the depth of penetration of weathering. The Antioxidant did not have an influence on color change in a long period of time، but was able to relatively decrease it in short term.