Towards sustainable wood–plastic composites: polymer types, properties, processing and future prospects

The growing environmental awareness has led to the sustainable utilization of waste for the development of value-added products. In this regard, several analysts and researchers have attempted to utilise wood flour wastes as reinforcements or fillers for various recycled and virgin polymer matrices to generate materials called wood–plastic composites. These composites are fabricated via compression moulding, injection moulding, additive manufacturing, extrusion, and other processes. In this review, the properties of WPCs manufactured using five different thermoplastic polymers (polypropylene, high-density polyethylene, low-density polyethylene, polyvinyl chloride, and polystyrene) combined with wood flour are discussed in detail. Owing to their biodegradability, low density, relatively low cost, high stiffness, and strong mechanical properties, WPCs are widely adopted in infrastructure, packaging, household, automotive, construction and building applications. The findings of this study provide a thorough understanding of the influence of different matrix types and wood flour on the properties of WPCs, encouraging researchers to conduct more research for the development of advanced wood composites to fulfil the dual task of minimising waste and producing value-added products for high-end applications.