SiO2气凝胶是具有优异性能的新型多孔纳米材料,是国内外热学、光学、声学及电学等学科的研究和发展热点.SiO2气凝胶的制备包括凝胶形成、凝胶老化及后处理3个阶段,其结构和性能与制备参数有关.对3个阶段制备参数的影响规律进行了综述.针对凝胶形成阶段,从硅源种类、化学配比、pH值、反应温度及水解时间5个参数进行概述;针对凝胶老化阶段,从老化温度与时间两个参数进行概述;针对后处理阶段,从干燥剂种类、改性剂种类和浓度及改性温度与时间5个参数进行概述.通过进一步探索制备参数对SiO2气凝胶结构与性能影响的规律,不断优化生产制备工艺,对推动SiO2气凝胶规模化生产及推广应用有指导意义.
Silica aerogels are a new type of nanoporous materials with excellent properties.It has been the hot spot of research and development in thermal, optical, acoustic and electrical and other disciplines at home and abroad.The preparation of silica aerogels can be divided into three general steps: gel preparation, aging of the gel and post-processing.Its structure and properties are associated with the preparation parameters.In this paper, the influence of preparation parameters on structure and performance of silica aerogel are reviewed.For the gel preparation, the silicon source type, sol proportion, pH value, reaction temperature and hydrolysis time are summarized.For aging of the gel, aging temperature and time are summarized.For post-processing, drying solvent species, modifier types and concentrations, modified temperature and time are summarized.Through exploring the preparation parameters which affect structure and performance of silica aerogels, and constantly optimizing the preparation technology, it will have great guiding significance for promoting scale production and applications of silica aerogels.
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