Study On Thermal Insulation Properties Of Silica-based Aerogel Panels In Different Environments

Aerogel is the lightest solid in the world.Its ultra-high porosity and extremely low density make it the green solid material with the lowest thermal conductivity.As the earliest industrialized and commercialized aerogel product,silicon based aerogel has been increasingly mature in its preparation methods.With the development of manufacturing technology,the mat,plate,glass,powder particles and other materials derived from silicon based aerogel have been gradually applied in the field of building thermal insulation.This paper mainly studies the influence of environmental factors on the thermal insulation performance of silicon based aerogel board,and designs non corrosive environment and corrosive environment.The non corrosive environment test mainly studies the influence of thickness factors on the selected silicon based aerogel board and the performance comparison between the selected silicon based aerogel board and traditional thermal insulation materials.Referring to the experimental method for studying the thermal performance of phase change materials,a small-sized test box test method was designed,and the temperature rise percentage and delay time of the specimen were further analyzed through the obtained temperature rise curve(ξ)And attenuation factor(ν)Important material thermophysical performance parameters.The results show that the order of thermal performance of silicon based aerogel board and traditional thermal insulation materials is: 3cm thick silicon based aerogel board>2cm thick silicon based aerogel board>3cm thick polyurethane foam(PU)board>3cm thick polystyrene foam extrusion(XPS)board ≈ 1cm thick silicon based aerogel board.The thermal insulation performance of silicon based aerogel board is proportional to the wall thickness.It shows that the silicon based aerogel board has higher thermal insulation performance than the traditional thermal insulation materials,and the silicon based aerogel board can have similar thermal insulation performance with the traditional materials even if its thickness is reduced within a certain range.In order to further study the thermal insulation mechanism of the material,SEM micro electron microscopy analysis was also conducted on the specimens used in non corrosive environmental tests.The results show that the microstructure of XPS board and PU board is mainly flocculent,while that of silicon based aerogel board is spatial column network,which can reduce the density and increase the porosity of materials.The high phase area and nanometer size distribution of the silicon based aerogel plate effectively block the temperature conduction path between materials,so that it presents good thermal insulation performance.In order to further study the impact of environmental factors on the thermal insulation performance of silicon based aerogel board,three erosion environment tests were designed,namely freezing thawing,alkaline and humidity.Similarly,the impact of erosion environment on the thermal insulation performance of silicon based aerogel board was studied through small-scale test box test and SEM micro electron microscope analysis.The results show that only considering the freezing and thawing factors,only a small amount of crystals are produced in the space structure of the silicon based aerogel plate after the freezing and thawing erosion,which does not have a significant impact on the original space column network structure.Moreover,the analysis results of the thermal insulation performance test show that with the increase of the freezing and thawing cycles,the thermal physical performance of each group of specimens decreases slightly,The results show that the thermal insulation performance of the silicon based aerogel board will not be greatly weakened by the erosion of freezing and thawing environment;Alkaline environment will lead to crystal accumulation of the original space column network in the silicon based aerogel board.At the same time,alkaline solution will also damage the fiber in the material,causing the attached silicon based aerogel powder particles to fall off,which will lead to a significant reduction in the thermal insulation performance of the silicon based aerogel board;Humidity environment will not only significantly reduce the time required for temperature transfer of silicon based aerogel plates,but also significantly reduce the resistance of materials to environmental temperature fluctuations;The thermal insulation performance of the silicon based aerogel board will be recovered after experiencing humidity and drying,but it cannot be recovered to the initial value.