基于水性气相二氧化硅浆料制备柔性二氧化硅气凝胶复合毡  

Fabrication of flexible silica aerogel composite blankets from an aqueous fumed silica-based slurry

作　　者：张舜尧 王鲁凯 冯军宗 姜勇刚 李良军 胡艺洁 冯坚 Shunyao Zhang;Lukai Wang;Junzong Feng;Yonggang Jiang;Liangjun Li;Yijie Hu;jian Feng(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory,College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]Science and Technology on Advanced Ceramic Fibers and Composites Laboratory,College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China

出　　处：《Science China Materials》2024年第4期1332-1339,共8页中国科学（材料科学）（英文版）

基　　金：supported by Hunan Provincial Natural Science Foundation of China (2023JJ30632);the Key R & D Program of Hunan Province (2022GK2027)。

摘　　要：二氧化硅气凝胶由于其低导热率在隔热应用方面具有巨大的潜力.然而,它们通常具有较差的机械性能,需要在保持低热导率的同时增强机械性能.本研究以商业化气相二氧化硅和甲基三甲氧基硅烷为硅源,并以水和乙醇为溶剂形成浆料.基于此,二氧化硅气凝胶块体(SAMs)可通过常压干燥进行制备,且无需额外的表面改性或溶剂置换.制备的SAMs保持了典型的纳米孔结构,具有低密度(0.24 g cm^(-3))、收缩率(4%)和热导率(0.046 W m^(-1)K^(-1)).通过辊压将浆料浸渍到纤维毡中,并通过浆料热固化和常压干燥制备出二氧化硅气凝胶毡(SABs).制备的SABs具有良好的柔韧性和机械性能,便于安装和隔热应用,并显著减少了生产周期和成本.此外,基于SAMs的纳米孔结构和低收缩率,通过调控遮光剂的粒径和质量分数进一步降低了SABs的高温热导率,优化后的SABs在800℃的热导率低至0.054 W m^(-1)K^(-1).Silica aerogels exhibit considerable potential for thermal insulation applications owing to their low thermal conductivity.However,they generally possess poor mechanical properties and need to be mechanically enhanced while maintaining their low thermal conductivity.In this study,commercial fumed silica and methyltrimethoxysilane were used as the silica sources and water and ethanol were used as solvents to form a slurry.Consequently,silica aerogel monoliths(SAMs)were prepared through ambient drying without additional surface modification or solvent replacement.The resulting SAM maintained a typical nanopore structure and exhibited low density(0.24 g cm^(-3)),shrinkage(4%),and thermal conductivity(0.046 W m^(-1)K^(-1)).The slurry was impregnated with fiber blankets via roller pressing,and silica aerogel blankets(SABs)were prepared through thermal solidification of the slurry and ambient drying.The prepared SABs exhibited good flexibility and mechanical properties,facilitating their installation and application for thermal insulation and considerably reducing production cycles and costs.In addition,controlling the particle size and mass fraction of opacifiers decreased the high-temperature thermal conductivities of SABs owing to the nanopore structure and low shrinkage of SAMs,and the thermal conductivity of the optimized SAB at 800℃ was as low as 0.054 W m^(-1)K^(-1).

关 键 词：常压干燥 二氧化硅气凝胶 气相二氧化硅 甲基三甲氧基硅烷 浆料制备 热导率 遮光剂 纤维毡 

分 类 号：TQ427.26[化学工程]