Recent progresses in wood-plastic composites: Pre-processing treatments, manufacturing techniques, recyclability and eco-friendly assessment

Wood-plastic composites (WPCs) have shown promising domestic and industrial applications. Both virgin and waste materials have been used as matrix and reinforcement materials in WPCs manufacturing which enhances the eco-efficiency of WPCs products. This study presents a comprehensive review on the WPCs manufacturing techniques including pre-processing of the composite ingredients and post-processing of the WPCs products. Three main types of pre-processing techniques have been discussed; chemical, mechanical, and thermal treatments. Conventional manufacturing techniques of WPCs such as extrusion molding, injection molding, compression molding, stir casting, and hot-press method have been presented. In addition, advanced manufacturing techniques such as selective laser sintering have been briefly discussed. The recycling of WPC is also discussed. Eco-friendly assessment of WPCs has been also introduced. Important conclusions and the future research trends have been mentioned in the end of the article.