三甲基硅烷化改性二氧化硅气凝胶

Trimethylsilyl substituent modification of silica aerogels

采用六甲基二硅氮烷对二氧化硅凝胶进行疏水处理,得到了疏水性的二氧化硅气凝胶。用红外光谱和热分析表征处理前后二氧化硅气凝胶的性质,用测量显微镜跟踪处理前后气凝胶柱在空气中直径变化。结果表明,处理后气凝胶的表面羟基明显减少,在空气中的吸潮性大大降低,圆柱体在空气中的径向收缩率从30%降至3%。

Low-density hydrophobic silica aerogels were produced by modification of conventional silica aerogels via substitution of --OH groups by trimethylsityls. IR spectra and thermogravimeturic anglyses were to characterize the aerogels before and after modification, And the diameter changes of modified and unmodified aerogel micro cylinders were tracked using a measuring microscope. The results show that the hydrophobic silica aerogels possess much higher stability than hydrophilic ones due to the diminishment of --OH groups and the radial shrinkage ratio of cylinder samples decreases dramatically from 30% down to 3% after modification.