Triple Thermal Management Wood–Plastic Composite\nPlate with Excellent Waterproof and Mechanical Properties

Wood–plastic\ncomposite (WPC) possesses the advantages of\nboth plastic and wood materials and has been widely applied to replace\nsolid wood both outdoors (floor and railing of park and garden) and\nindoors (floor, wallboard, furniture, etc.). However, there will be\nhigh surface temperature (more than 55 °C) for outdoor applied\nWPC plates in the summer, which seriously affects the thermal comfort\nof human. Herein, we propose a triple thermal management strategy\nto solve the above problem of WPC plates by combining heat conduction,\nhigh solar reflection, and radiation cooling to quickly dissipate\nheat while blocking solar absorption, and fabricate a trilayer WPC\nplate with excellent comprehensive properties. The embedded titanium\ndioxide (TiO<sub>2</sub>) nanoparticles not only significantly improve\nthe solar reflectance (53.8%) and mid-infrared emissivity (89.2%)\nof the colored top layer but also endow the surface with good hydrophobicity\nand abrasion resistance. By incorporating hexagonal boron nitride\n(h-BN) and short-cut glass fibers (GF) into the core layer of the\nWPC to enhance the thermal conductivity (0.9–1 W/(m·K))\nand impact strength (8.7 kJ/m<sup>2</sup>), the heat accumulation\nof the surface and the overall mechanical strength are improved. For\nthe bottom layer, addition of h-BN increases its thermal conduction\nand improves downward thermal transfer from the surface besides the\nwater-proof function. Notably, the outdoor tests show that the trilayer\nWPC plate can keep around 45 °C, about 10 °C lower than\nthe ordinary WPC plate under direct sunlight. This strategy of combining\nthermal conduction, high solar reflection, and radiation cooling offers\npromising avenues for developing advanced thermal management WPC plates\nand cooling designs for other outdoor facilities.