Development of SiO₂ nanofibre fillers with low-thermal conductivity by regulating heat-treatment process

Silicon dioxide (SiO₂) is considered to be a promising material for thermal insulation. However, the application scenarios of insulation materials are limited, and how to enhance their practical application value has been an attractive research topic. In this work, SiO₂ nanofibres were prepared by the electrospinning technology. Effects of different heat-treatment parameters on SiO₂ crystal transformation, nanofibres’ diameter and thermal conductivity were investigated, and the thermal-insulation mechanism of SiO₂ nanofibres was further studied. Results of the study show that the heat-treatment process has a significant effect on nanofibre diameter, which affects thermal conductivity. When the heat-treatment temperature is 900°C, the heating rate is 8°C min⁻¹ and holding time is 2 h, the diameter of SiO₂ nanofibres is the finest, and thermal conductivity is the lowest (0.039 W mK⁻¹). In addition, nanofibres is demonstrated as functional fillers of thermal-insulation coating, which exhibit excellent thermal insulation and mechanical properties. This study can provide a certain reference value for the development of new lightweight and functional thermal-insulation fillers.