Ultraviolet-Shielded Transparent Wood with Improved Interface for Insulating Windows

Abstract

Recently, transparent wood (TW) has been considered for many energy-efficient building products, such as windows and decorations. However, the existing TW still faces issues with size and thickness, as well as problems with functional fillers affecting the optical and mechanical properties of TW, which limits its wide application in the window products. In this study, a wood composite material (WCM) with good optical, mechanical, and thermal insulation and UV-shielding properties was prepared by using delignified wood (DW), methyl methacrylate (MMA), and 4-vinylphenylboric acid (VPBA). Compared with NaClO₂ delignification, peracetic acid (PAA) preserves hemicellulose and a more stable pore structure, which facilitates the filling of polymers into the DW template, resulting in the preparation of more extensive and thicker TW. VPBA, as a functional raw material for UV shielding, on the one hand, improves the interfacial compatibility of the TW, thus improving the optical properties (transmittance of about 90%, haze of about 55%) and mechanical properties (64.5 MPa). On the other hand, WCM was found to effectively block UV–C, UV–B (about 100%), and UV-A (about 90%) radiation while maintaining sufficient visible light transmittance. In addition, as an insulating window, WCM has low thermal conductivity and can maintain a high temperature for a long time after the loss of solar radiation, which is an ideal thermal insulation material and is expected to become a potential substitute for conventional glass.