二氧化硅气凝胶纤维保温材料的机械性能(英文)

Mechanical Property of Silica Aerogel Fibers Composite Insulation

以多聚硅E-40为硅源,采用溶胶-凝胶法制备纳米多孔二氧化硅气凝胶掺杂莫来石纤维复合材料。莫来石纤维在二氧化硅气凝胶里起到骨架支撑作用,用来提高复合材料的机械性能。SE用M来表征二氧化硅气凝胶纤维复合材料的的形貌和孔结构。动态力学分析仪和热导率测试仪用来表征复合材料的机械性能和热导率。结果表明,二氧化硅气凝胶纤维复合材料经过高温处理后,仍然保持多孔结构和高孔洞率,其机械强度从1.5×10~5Pa提高到3 8×10~6Pa。随着热处理温度的升高,机械性能可以提高10到20倍。室温条件下二氧化硅气凝胶的热导率为0.023 W/(m·K),经过1000℃热处理后二氧化硅气凝胶纤维复合材料的热导率是0.032W/(m.K),仍是一种很好的超级保温材料。

Nano-porous silica aerogels doped with mullite fibers were prepared via sol-gel progress with polyethoxydisiloxanes(E-40) as silicon source.The mullite fibers were distributed inside the silica aerogels to act as a supporting skeleton material,which could increase the mechanical property.The morphology and pore structure of silica aerogels doped with fibers were characterized by SEM.The mechanical properties and the thermal conductivities of silica aerogel-fiber composites were determined by a dynamic mechanical analyzer and a hot disk device.The silica aerogels doped with fibers still maintain a spongy porous structure and high porosity,even after the heat treatment.The mechanical strength of the silica aerogels increases from 1.5×10~5 to 3.8×10~6 Pa.With the rising of the heat treatment temperature,the mechanical strength of the composites would be increased to 10-20 times.The thermal conductivity of silica aerogels is 0.023 W/(m·K) at room temperature in air.The thermal conductivity of the composites is 0.032 W/(m-K) after 1000 ℃ and is still recognized as the preferred super-insulation material.