正硅酸乙酯水解-聚合的工艺参数研究及纳米SiO_2的合成

Study on Process Parameters for Hydrolysis and Aggregation of Ethyl Silicate and Synthesis of Nanosilica

以正硅酸乙酯为原料,分别以盐酸、硫酸、甲酸、天冬氨酸或其混合酸为水解催化剂制备硅溶胶。研究了不同催化剂、电解质以及醇对水解和胶凝过程的影响,结果发现,以盐酸或以盐酸和天冬氨酸的混合酸为催化剂可以得到较好的硅溶胶,而单独以有机酸和天冬氨酸为催化剂得不到理想的硅溶胶。同时还发现,醇的加入可以起到稳定硅溶胶的作用,而浓度较高的Na2SO4加剧了硅溶胶的聚结。另外,用X-射线衍射和紫外-可见光反射对纳米SiO2 进行了分析。

The preparation of colloidal silica is introduced. The raw material ethyl silicate is hydrolyzed with water in the presence of iso-propyl alcohol, and the acid is introduced into the mixture as catalyst. The catalysts of the hydrolysis are hydrochloric acid, sulfuric acid, methane acid and amino acid respectively by study on the mechanism of the hydrolysis, and the amino acid is found as the effective catalyst in the presence of very small amount of hydrochloric acid.This has never been found in the previous references. The silica sol prepared with varies acid has different characters. Also it is found that alcohol can stabilize the colloidal silica while sodium sulfate increases the agglomeration of colloid silica. In the end, nanosilica is characterized by X-ray diffraction and UV-Vis reflective spectrum.