Recycling end-of-life WPC products into ultra-high-filled, high-performance wood fiber/polyethylene composites: a sustainable strategy for clean and cyclic processing in the WPC industry

As “green” composites, recycling end-of-life wood-plastic composites (WPCs) is crucial for sustainable and efficient resource utilization and carbon neutrality. In this study, waste WPC windows with 47.6 wt.% wood fiber (WF) were recycled as the polymer matrix and then reprocessed with waste WFs by extrusion into ultra-high-filled WF/polyethylene composites (UH-WPCs) using MAPE as a compatibilizer. The tensile and flexural moduli of all UH-WPCs with/without MAPE were higher than those of the waste WPCs. The MAPE-compatibilized UH-WPCs demonstrated improved water resistance, creep resistance, and dimensional stability. The tensile strength, tensile modulus, flexural strength, and flexural modulus of the UH-WPCs with 80 wt.% WF and 4 wt.% MAPE were 26.6%, 50.0%, 26.4%, and 87.9% higher than those of the waste WPCs, respectively. The presence of MAPE could improve the WF-matrix interfacial interaction and protect the WF from damage during reprocessing owing to the improved wettability and plasticization on WF. It is anticipated that the proposed strategy will provide a facile method to recycle end-of-life WPC products into high-performance composites at a low cost.