Rapid synthesis of water-glass based aerogels by in situ surface modification of the hydrogels
Rapid synthesis of water-glass based aerogels by in situ surface modification of the hydrogels
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DOI：
10.1016/j.apsusc.2006.07.016
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发表时间：
2007-01-15
影响因子：
6.7
通讯作者：
Yeo, Jeong-Gu
中科院分区：
文献类型：
--
作者：
Bhagat, Sharad D.;Kim, Yong-Ha;Yeo, Jeong-Gu
本研究的目的是减少通过常压干燥合成的水玻璃基气凝胶的加工时间。为了这个目的，我们采用了共前体的方法，在水凝胶中使用三甲基氯硅烷（TMCS）和六甲基二硅氮烷（HMDS）的表面改性。表面改性导致水凝胶中孔隙水的置换，从而绝对避免了耗时的溶剂交换步骤。通过傅立叶变换红外光谱（FTIR）中2900、1400、1255和845 cm（-1）处的Si-CH 3峰的存在证实了三甲基硅（-Si（CH 3）（3））基团连接到二氧化硅表面。差热分析（DTA）显示，气凝胶保持其疏水行为高达500摄氏度的最高温度，高于该温度时，它们变得亲水。的二氧化硅气凝胶的物理和纹理特性已被报道，并已讨论的结果，考虑到表面改性和从水凝胶中排出的孔隙水的量。(c)2006 Elsevier B. V.保留所有权利。
The objective of the present research was to reduce the processing time of water-glass based aerogels synthesized via an ambient pressure drying. For this purpose we employed a co-precursor method for the surface modification in hydrogels using trimethylchlorosilane (TMCS) and hexamethyldisilazane (HMDS). The surface modification resulted in the displacement of pore water from the hydrogels and thereby absolutely avoiding the time-consuming solvent exchange step. The attachment of trymethylsilyl (-Si(CH3)(3)) groups to the silica surface was confirmed by the presence of Si-CH3 peaks at 2900, 1400, 1255 and 845 cm(-1) in the Fourier Transform Infrared (FTIR) spectra. The differential thermal analysis (DTA) revealed that the aerogels maintain their hydrophobic behavior up to a maximum temperature of 500 degrees C above which they become hydrophilic. The physical and textural properties of the silica aerogels have been reported and the results have been discussed by taking into account the surface modification and the amounts of the pore water displaced out from the hydrogels. (c) 2006 Elsevier B.V. All rights reserved.