高岭石表面的有机硅烷化可以显著提高其表面与有机物的亲和性,从而在纳米复合材料、环境吸附材料等领域具有广阔的应用前景,是实现高岭石资源高效利用的重要途径。先将二甲基亚砜(DMSO)与高岭石反应,获得DMSO插层高岭石前驱体;然后采用自制的密闭容器动态调压装置,在N2气气氛下,分别在117、173和200℃3个阶段,使DMSO插层高岭石与γ-氨丙基三乙氧基硅烷(APTES)充分反应。反应产物的X射线衍射、Fourier变换红外光谱及热重–差热分析结果均表明,APTES成功嫁接于高岭石的内表面,获得了APTES嫁接高岭石复合物。嫁接产物的d(001)=0.997nm,表明APTES已成功进入高岭石的层间;同时,嫁接反应后,高岭石内表面羟基伸缩振峰(3695cm–1)的强度显著减弱,说明在嫁接反应过程中,内表面羟基参与了缩合反应并消耗了部分内表面羟基;在其热重曲线中,位于430℃附近的质量损失主要归因于嫁接有机硅的脱失。与已有研究成果相比,采用密闭容器动态调压装置,以分步升温法可以降低有机硅烷嫁接反应的温度、减少N2用量。
Silylation is efficient to improve the compatibility between clay mineral and organics. The obtained materials display potential industrial applications such as clay/polymer composites and novel adsorption materials. In this paper, the precursor of kaolin- ite/dimethyl sulfoxide (DMSO) complex was obtained via intercalation reaction. The silylation of the obtained precursor was conducted in a designed hermetic container with y-aminopropyltriethoxysilane (APTES) under N2 at 117, 173 and 200 ℃, respectively. The results demonstrate that APTES is grafted on the inner surfaces of kaolinite. The silylated product shows a basal spacing at d(00l)= 0.997 nm, indicating the effective intercalation of APTES. A decrease of peak intensity at 3 695 crn-1 in Fourier transform infrared spectrum of the silylated product, due to the stretching vibration of inner surface hydroxyls, indicates a consumption of the inner surface hydroxyls during condensation between kaolinite and APTES. The mass loss at 430 ℃ in the thermogravity curve of the sily- lated product should be attributed to the decomposition of the grafted APTES. The silylation of kaolinite inner surfaces via thermal treatment in the hermetic container can reduce the reaction temperature and the consumption of N2.