High-performance poplar-polyethylene laminates based on microwave-assisted acetic acid pretreatment process with potential application in construction

The issue of white pollution has gained more attention in recent years on a global scale. Using fast-growing wood and plastic waste to produce wood-plastic composites can effectively increase the plastic recovery rate while relieving the pressure of structural shortage of wood resources in many countries. Hence, this study demonstrates an innovative approach to prepare a good-quality wood-plastic laminates based on wood-plastic composites. Poplar veneer was first pretreated with microwave-assisted acetic acid followed by a one-step thermal forming process with powdered polyethylene (PE) to produce the glue-free wood-plastic laminates. It was found that the pretreated composite has a tensile strength of up to 280 MPa and specific strength of up to 205.98 kNm/kg. The excellent mechanical properties can be attributed to the mechanical interlock between wood fibre and polyethylene, plus the closer bond among the fibres induced by cell wall collapses during hot-pressing. Furthermore, the water contact angle of the composite surface remains at about 84° after 10 s. That suggests its good surface waterproof performance which is attributed to the partial degradation of hemicellulose during the pretreatment and the coating of wood fiber with polyethylene. Overall, we have developed glue-free, high-strength, and heat-resistant wood-plastic laminates applicable to interior furniture and outdoor building facilities. This is imperative for protecting the ecological environment and reducing the pressure on structural shortages of wood resources worldwide.