Delignified wood biocomposites as sustainable and transparent materials for passive cooling applications

Wood possesses unique structural and functional properties that make it a promising material for the development of windows. In this study, the potential use of wood biocomposites as a window materials was explored by delignification of local Indonesian woods, such as mahogany (Swietenia macrophylla), sungkai (Peronema canescens), mindi (Melia azedarach), and maple (Acer laurinum), using NaOH and H2O2 followed by epoxy resin impregnation. Macroscopic observations, optical transmittance (τ), tensile and bending strength tests were performed to evaluate their optical and mechanical properties. An infrared exposure simulation was also conducted to assess the material passive cooling capabilities in a room model. The results revealed that mahogany and maple had the highest τ values (86.03 and 81.43, respectively). Transparent mahogany wood exhibited haze due to optical scattering but showed strong mechanical properties with an ultimate tensile strength (UTS) of 78.83 MPa and a strain (ϵ) of 2.67. Transparent maple wood had UTS of 84.67 MPa and ϵ of 2.32. The use of transparent mahogany and maple in room model reduced the temperature difference between indoor and outdoor environments by up to 11.5°C and 10.5°C, respectively, which suggests that transparent wood can be used as a window material for sustainable passive cooling applications. © 2023 Informa UK Limited, trading as Taylor & Francis Group.