Silica aerogel8/3/2023 ![]() ![]() The thermal insulation and hydrophobicity of the impregnated wood were measured to examine the influences of particle size of silica aerogel powders and the number of impregnation cycle on the material properties.įull size image Silica aerogel-impregnated wood process The microstructure of the impregnated wood was observed by scanning electron microscopy (SEM) to reveal the dispersion of silica aerogel in the wall and lumen of wood cells. Compared with the complication of in situ polymerization followed by supercritical CO 2 drying to form silica aerogel in the wood, the direct impregnation of commercial silica aerogel powders into wood is more straightforward and cost-effective, which makes it more practical in the industry. To our knowledge, there are no reports on directly applying commercial silica aerogel powders to wood. In this study, we adopted a simple and industrially scalable process, in which commercial silica aerogel powders suspended in ethanol medium were applied directly to the wood through a facile vacuum impregnation, to improve its thermal insulation and hydrophobicity. Silica aerogel powders are easily manufactured and readily available in the market. This process is complicated and expensive, which lowers its acceptance by manufacturing factories that produce wood-based materials for interior decoration and buildings, such as plywood, laminated veneer lumber (LVL), thus greatly limiting its industrial application. However, the situ synthesis of silica aerogel in the wood was usually prepared by the sol–gel method via drying under ambient pressure or drying with supercritical CO 2. ![]() The mechanical properties and thermal properties of wood could be enhanced after being impregnated with silica sol. It was reported that thermal insulation, flame retardancy, and dimensional stability of wood could be significantly improved through in situ polymerization of silica aerogel in the wood cell lumen. To date, wood modified with silica aerogels is mainly by means of in situ synthesis or impregnation with sol. Due to its attractive features of thermal insulation and flame retardancy, silica aerogel has been extensively applied to wood, fiber-reinforced composites, cement-based composites, glass materials and other nanocomposites. Silica aerogel with ultra-low density and highly crosslinking structure has been regarded as one of the most efficient thermal insulating materials in addition to its excellent flame retardancy. Therefore, searching for a simple, cost-effective, and industrially scalable approach is highly needed to enhance thermal insulation and hydrophobicity of wood, especially for the treatment on the less inferior fast-growing wood. Moreover, wood is sensitive to water due to the hydrophilic nature of its main chemical components cellulose and hemicellulose, which often leads to low dimension stability of wood or wood-based products. The thermal conductivity of wood is relatively high (about 0.1 W m −1 K −1), but the wood with high thermal insulation is desired in interior decoration and construction applications. ![]() Wood, a sustainable material, possesses unique visual properties and is friendly to humans and the environment, which has long been used in interior decoration and construction. With the awareness of energy-saving and the sustainability goals, the demand for thermal insulation sustainable products is increasing in building or interior decoration. The results indicate that the impregnation of silica aerogel powders in wood can be a facile and efficient approach to prepare wood with thermal insulation and hydrophobicity, which may hold great promise to be employed in manufacturing wood-based materials used in interior decoration and buildings. The tensile properties of the impregnated wood were found slightly improved. The water contact angle of the impregnated wood increased up to the maximum values 153° with a comparison with 80° of the untreated wood, indicating effective hydrophobization after silica aerogel impregnation. The results showed that the thermal conductivity of silica aerogel-impregnated wood decreased by approximately 38%. The effects of particle size (20 µm and 40 nm) of silica aerogels and the number of impregnation cycles (1, 3, and 5 cycles) were examined on the thermal conductivity and the surface hydrophobicity. Herein, we attempted to use commercially available silica aerogel powders suspended in ethanol to treat the wood by a simple vacuum impregnation process. The aim of the study was to develop a simple and cost-effective method to improve thermal insulation and hydrophobicity of wood. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |