Co-Extruded Wood-Plastic Composites: Their Structure, Properties, and Applications

Abstract

Wood-plastic composites (WPCs) are innovative materials prepared by mixing wood fibers, thermoplastics, and additives through extrusion, injection molding, or compression molding processes. Co-extruded WPCs (Co-WPCs) are multilayer composites, in which regular WPCs are coated with a protective shell layer through coextrusion. The core-shell structure of Co-WPCws provides a way to overcome the shortcomings of WPCs by modifications specific to the composite surfaces. With the development of coextrusion technology, Co-WPCs show promise to become one of the important leading directions of the WPC industry. Based on the special characteristics of the core-shell structure, the properties of Co-WPCs were reviewed in this chapter, including mechanical properties, dimensional stability, weather resistance, flame retardancy, etc. Furthermore, the applications of Co-WPCs were comprehensively presented. Finally, the problems and challenges in the development of Co-WPCs were put forward, and the key points of future research were also expounded.