二元炭质-二氧化硅干凝胶和气凝胶前驱体的制备

Preparation of Binary Carbonaceous-Silica Xerogel and Aerogel Precursors

以正硅酸乙酯和炭质水性中间相为原料，分别制得了炭质醇溶胶和硅醇溶胶，将二者进行混合后再利用常压干燥法和超临界流体干燥法分别制备了二元炭质－二氧化硅干凝胶和气凝胶粉末．并采用氮吸附、ＦＴ－ＩＲ、ＴＥＭ和ＸＲＤ等测试手段对所制得的干凝胶和气凝胶粉末的ＢＥＴ表面积、表面形貌、结构和组成进行了表征．结果表明二元干凝胶由几乎球形的、团聚的、无定形二元炭质－二氧化硅颗粒组成，其颗粒尺寸为８０～２２０ｎｍ．而二元气凝胶具有较疏松的外观结构和良好的流动性，并且由球形的、分散性较好的、无定形二元炭质－二氧化硅颗粒组成，其颗粒尺寸为１０～６０ｎｍ．

The carbonaceous alcosol and the silica alcosol were prepared respectively by using aqua-mesophase and tetraethoxysilane (TEOS) as starting materials. Then the two alcosols were mixed and dried in open air and under supercritical fluid conditions to form binary carbonaceous-silica xerogel powders and aerogel powders respectively. The morphology, structure and composition of binary xerogel powders and aerogel powders were characterized by FT-IR, TEM, XRD and nitrogen adsorption. The results show that the binary xerogel powders are composed of almost spherical, agglomerated and amorphous binary carbonaceous-silica particles. The particle sizes of binary xerogel are about 80 similar to 220nm. The binary aerogel powders, which show loose appearance structure and good fluidity, consist of spherical, well-disposed and amorphous binary carbonaceous-silica particles. The particle sizes of the binary aerogel are over the range of 10-60nm.