超轻耐火SiO2纳米纤维气凝胶的制备及性能研究

Preparation and properties of ultralight and fire-resistant SiO2 nanofibrous aerogels

以二氧化硅(SiO2)纳米纤维(SNF)为基体,通过淀粉修饰制备了增韧超轻SiO2纳米纤维气凝胶(SNFAs)。探讨了SNF与淀粉的质量比对SNFAs的表面形貌、力学性能、隔热性能、热稳定性的影响。结果表明:增韧SNFAs内部的纳米纤维形成互连的三维网络结构;随着淀粉添加比例的增加,SNFAs的压缩强度先增大后减小,密度逐渐增大,导热系数先减小后增大,当SNF与淀粉质量比为10.25时,SNFAs压缩强度最大为9.0kPa,密度为11.5mg/cm^3,导热系数为0.0258W/(m·K),比纯SNFAs导热系数低;制备的SNFAs在维持高隔热性能前提下,能够改善SNFAs的力学性能,具有低密度、低导热系数、耐火隔热的特点。

The starch toughened ultralight SiO2 nanofibrous aerogels(SNFAs)were prepared by using silica(SiO2)nanofibers(SNF)as the matrix.The effects of SNF and starch mass ratio on the surface morphology,mechanical properties,thermal insulation performance and thermal stability of SNFAs were discussed.The results showed that the toughened SNFAs formed a three-dimensional network structure of nanofiber interconnection;the compressive strength of SNFAs first increased and then decreased,the density gradually increased,and the thermal conductivity first decreased and then increased with the increase of starch content;the maximum compressive strength of SNFAs was 9.0 kPa,the density 11.5 mg/cm^3 and the thermal conductivity 0.0258 W/(m·K),lower than that of pure SNFAs,when the mass ratio of SNF to starch was 1 0.25;the mechanical properties of SNFAs can be improved in the premise of maintaining high thermal insulation performance;and the obtained SNFAs had the characteristics of low density,low thermal conductivity,fire resistance and thermal insulation.