Abstract: The SiO₂ aerogels based composite core materials were prepared by wet and dry molding techniques using SiO₂ aerogels and glass fiber short cutting as the main raw materials, and then the nano SiO₂ aerogels composite core vacuum insulation panels (VIP) were obtained by vacuum packaging technology. The microstructure of composite core materials with different SiO₂ aerogels contents (mass fraction) was studied, and the differences of the two processes on the thermophysical properties of VIP were compared and analyzed. The results show that the addition of SiO₂ aerogel makes the three-dimensional network structure of the short-cut fiber core become compact, but the high content of aerogel will lead to poor adhesion between the aerogel and the fiber. With the increase of SiO₂ aerogel content, the density of composite core material decreases, and the compression rate and rebound rate of vacuum insulation panel also decrease. The homogeneity of composite core material prepared by wet process is slightly poor when the aerogel mass fraction is 35%, while the thickness of composite core material prepared by dry process is less than 0.04 mm, and the homogeneity is better. The thermal conductivity of the composite core VIP prepared by the wet process increases significantly with the increase of SiO₂ aerogel content, while the VIP thermal conductivity increases relatively small under the dry process, and the thermal conductivity is more stable.

Key words: SiO₂ aerogel, vacuum insulation panel, thermal conductivity, physical property