纤维对气凝胶复合材料导热和力学性能的影响研究

采用酸碱两步催化制备硅溶胶，将3种不同类型的纤维（如玻璃纤维、涤纶纤维和静电纺聚偏氟乙烯微纳米纤维等）作为增强材料，在常压干燥条件下制备出结构稳定的纤维增强气凝胶隔热复合材料．研究了纤维种类、直径等对复合材料结构、力学性能和导热性能的影响，结果表明，气凝胶隔热复合材料的导热系数约在0．025～0．028W·m-K^-1间，与常温下静止空气导热系数接近，具有较好的隔热保温性能；而气凝胶复合材料的抗压强度较纯气凝胶大幅提高了4～5倍，其中以微纳尺度静电纺纤维增强的气凝胶复合材料还具有较好的柔性和结构完整性．

Effects of reinforced fibers on thermal and mechanical properties of aerogel composites for thermal insulation

Monolithic aerogel composites with stable structures were successfully prepared by adding three types of fibers（ viz. , aligned glass monofilaments, polyester fibrous battings and electrospun polyvinylidene fluoride micro/nano fibers） into silica sols and following drying at ambient pressure. Effect of the types and diameters of the reinforced fibers on the structure, thermal conductivity and mechanical properties of the aerogel composites were investigated. The results showed that the monolithic aerogel composites had low thermal conductivities of 0. 025 - 0. 028 W · m^- 1· K^-1 close to that of still air. The compressive strength could be 3 - 4 times higher than that of the pure aerogels. Moreover, the monolithic aerogel composites reinforced by miero/nano electrospun polyvinylidene fluoride fibers had better flexibility and integrity.