化学络合法在溶胶－凝胶过程中的应用

APPLICATION OF CHEMICAL COMPLEXATION APPROACH IN SOL-GEL PROCESS

在利用溶胶－凝胶技术制备先进玻璃及陶瓷时，经常碰到诸如这样一些问题：金属醇盐先驱体在醇中的溶解度小；反应活性大，易生成沉淀；而且一些醇盐很难直接买到。化学络合物方法可以克服这些缺点。本文阐述了添加络合剂的络合方法在溶胶－凝胶上的应用，包括如下几个方面：（１）改变一些醇盐的溶解度，使之溶解在醇溶剂中；（２）控制先驱体的反应活性；（３）变非醇盐先驱体为醇盐光驱体；（４）合成有机－无机复合材料；（５）通过络合剂的作用合成一些易潮解的凝胶；最后讨论了络合物凝胶的分子设计等问题。

In the application of sol-gel process to the preparation of advanced glass and ceramics , somedrawbacks are usually found in the use of metal alkoxide precursors, such as low solubility, high reactivity andunavailable in the market. To overcome these drawbacks, the complexation approach is often applied with addi-tion of complexing agent. This paper is to present a discussion on application of the cornplexation approach in sol-gel process via chemical addition of organic complexing agents, based mainly on the research data and findingsin our laboratory with some published results as references. Problems included in the discussion are : improvementof the solubility of metal alkoxide precurxor, mod ification of reactivity of precursor,transformation of non-alkoxyl precursor into complexing specis with alkoxyl chracteristics, productioin of hybrid organic-inotganicmaterials, and synthesis of easily-liquefied gel by means of complexing agents. Finally, the molecular detqign ofcomplex gel is discussed.