常压干燥制备二氧化硅气凝胶

Preparation of Silica Aerogels via Ambient Pressure Drying

二氧化硅气凝胶是典型的纳米多孔轻质材料,由于具有独特的性能并在许多领域存在潜在的应用价值而受到广泛关注。二氧化硅气凝胶的制备传统上采用超临界干燥工艺,但此工艺成本高、工艺复杂而且具有一定的危险性。为了实现二氧化硅气凝胶的大批量生产和商品化应用,研究低成本常压干燥制备技术非常必要。目前常压干燥制备工艺已取得了较大进展,本文主要介绍了二氧化硅气凝胶的常压干燥制备方法及其特点,并概述了二氧化硅气凝胶复合材料制备的最新研究进展。以纤维和聚合物为增强体的二氧化硅气凝胶复合材料改善了气凝胶的力学性能,进一步扩宽了其应用范围。

Silica aerogels are the lightest materials with a typical interconnected nanostructure. They have received much attention due to their extraordinary properties and their potential applications in many fields. Conventionally silica aerogels have been made by supercritical drying process which is complicated,expensive and unsafe to a certain extent. In order to promote the production of silica aerogels on a large scale and for commercial applications,it is urgently necessary to probe the preparing technique of silica aerogels via ambient pressure drying at a reasonable cost. In recent years,significant developments in the ambient pressure drying technique have been achieved. This article gives an overview of the recent research progresses in preparation methods of silica aerogels via ambient pressure drying technique and the most updated information in preparation of silica aerogel composite materials. Silica aerogel composite materials reinforced by fiber and polymer improve the mechanical properties and further widen the application areas of silica aerogels.