SiO_2-C复合气凝胶的制备及其结构

以间苯二酚(R)和甲醛(F)为碳源,以3-胺丙基三乙氧基硅烷(APTES)为硅源,一步溶胶一凝胶法简单快捷地合成了SiO_2-RF复合气凝胶,高温碳化后得到SiO_2-C复合气凝胶,并用扫描电镜、比表面分析仪对所得样品的结构进行了研究,并讨论了不同投料比对气凝胶结构的影响.结果表明碳化前,投料比APTES/R=1时,所得气凝胶具有最大的比表面积(S_(BET)=606.1 m~2/g),碳化后,由于体积收缩和酚醛热解产生新孔隙双重因素的影响,投料比AFTES/R=1/2时样品的比表面积达到最大(S_(BET)=704.2 m~2/g).

Preparation and Structural Investigation of SiO_2 -C Composite Aerogel

SiO_2 - RF composite aerogels were prepared by one-step sol-gel method by using resorcinol ( R), formaldehyde (F) and 3-aminopropyltriethoxylsilane (APTES) as starting materials. After carbonization, SiO_2 - C composite aerogels were obtained. The structure of the aerogels was characterized by scanning electron microscopy and nitrogen adsorption/desorption analysis. The structure of SiO_2 - RF snd SiO_2 - C composite aerogels are strongly de-pendent on the APTES/R molar ratio. When APTES/R = 1, SiO_2 - RF composite aerogel has the highest specific sur-face area S_(BET)(606. 1 m~2/g). However,the highest specific surface area S_(BET)(704.2 m~2/g) is obtained when APTES/ R = 1/2 after carbonization for two reason:volume shrinkage and new pore come into being.