Application of Sustainable Wood-Plastic Composites in Energy-Efficient Construction

Abstract

Wood–plastic composites (WPCs), abbreviated as WPCs, are typically composite materials made by mixing wood flour and thermoplastic resins, and then shaped through processes such as extrusion or compression. They have emerged as a viable and advanced alternative to traditional wood and plastic materials, offering an amalgamation of the best properties of both. This study utilized discarded milk bottles as the polymer matrix (mainly composed of high-density polyethylene, HDPE) and added wood flour, recycled protective clothing (Tyvek®), and diatomite recycled from brewery waste as reinforcement. Additionally, pre-treated aluminum hydroxide powder from waste artificial marble was added. The results indicated that the optimal processing temperature for the WPCs was 175 °C. The mechanical properties of the material increased with the addition of recycled protective clothing and pre-treated aluminum hydroxide powder. The increase in tensile strength can reach up to 28%. The thermal conductivity of the WPCs also significantly increased with the addition of pre-treated aluminum hydroxide powder. Furthermore, sunlight analysis showed that the surface temperature of the WPCs decreased by approximately 8.5 °C, which corresponds to a reduction of 13% after adding pre-treated aluminum hydroxide powder. Therefore, they can be applied to outdoor cool WPCs to reduce the risk of foot burns or used as roof heat-insulating layers to reduce indoor air conditioning usage, achieving energy-saving and carbon reduction. This study demonstrates that high-performance and high-value green plastics made from various recycled materials can contribute to the goals of a circular economy and sustainable carbon reduction.