Other researchers also successfully removed the lignin from wood by using sodium hypochlorite in acid environment (Gan et al. Fink ( 1992) used sodium hypochlorite to remove a large amount of lignin from the wood to achieve the bleaching effect. Then, the optical transparency of wood can be improved by impregnating the material with a refractive index similar to that of the cell wall (~ 1.56) to reduce the light refraction in the propagation process of light path (Fink 1992). Specifically, firstly, the colorless wood template is obtained by removing the colored chemical components inside the wood, such as the colored groups of lignin and other chromogenic substances. The preparation methods of TW can be divided into two steps: bleaching and impregnation. Transparent wood (TW) is a kind of biomass composite material obtained by modifying wood, such that it has the potential to be used as energy-saving building material (Li et al.
2011 Tsioptsias and Panayiotou 2011 Fang et al. 2011), resulting in a variety of biomass composite materials with specific functions (Sun et al. It has attracted material researchers to carry out physical and chemical modifications (Kiguchi et al. 2016a), wood has the advantages of high mechanical properties and light weight. As a kind of abundant renewable biological resource on earth (Zhu et al. Based on natural materials, biomass materials meet the requirements of sustainable development and have the potential to replace petroleum-based materials for large-scale applications (Ates et al. In addition to the direct use of natural resources, reducing the application of petroleum-based materials in daily life also is one of the ways to solve the problem of energy consumption. Glass is one of the most commonly used energy-saving building materials. 2020) and make use of sunlight to meet people's needs for indoor light during the day (Borisuit et al.
For example, in terms of saving photoelectric resources, we can use energy-saving building materials (Li et al.
2008), and the use of natural resources is the most common way to solve this problem. The method has successfully improved the function and structure of transparent wood, and the highly transparent compressed wood is a new functional material with application potential.Įnergy consumption is one of the hot topics that people have been paying attention to for a long time (Nejat et al. Moreover, the transparent compressed wood has better mechanical properties (maximum tensile strength was 113.75 MPa, Young's modulus was 2.276 GPa) and thermal stability. The transmittance is increased by 34.1%, the haze decreased by 28.1%, and the transparent effect is more excellent through the cell wall densification of the delignification template. Then, the resin with similar refractive index to cell wall is vacuum impregnated into the dense wood template, and the transparent compressed wood with high transparency is successfully obtained. The external force is applied to the delignified wood template by using a press to make the radial thickness of the wood template smaller, and finally, a more compact and uniform wood template with cell wall skeleton is obtained. In this work, the top-down modification method is used to densify wood cell walls.
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