原位聚合法制备石蜡微胶囊的工艺研究

考察了助剂类型和后处理工艺对微胶囊制备的影响。结果表明，表面活性剂的加入会影响微胶囊形成，加入4．0％的表面活性剂得不到微胶囊，而在不加助剂或加入聚乙烯醇时能够得到较高微胶囊化率的微胶囊。制备石蜡微胶囊必须考虑后处理工艺的影响，需依次用热水、乙醇和热石油醚洗涤才能除去未包覆石蜡。通过对微胶囊合成过程的分析表明，要形成石蜡微胶囊，必须使生成的物质具有在石蜡液滴表面富集的能力。尿素和甲醛反应生成的缩聚产物具有一定的表面活性，逐渐移动到两相界面，在水相中进一步反应、沉积，包覆石蜡形成微胶囊。

Research of preparation of paraffin microcapsules by in situ polymerization

In this essay, effects of aids and treatment methods on the preparation of microcapsules were investigated. The result showed that the aids had great effects on the synthesizing microcapsules. Microcapsules can not be made when it had been added with 4.0% surfactant while it could make the high microencapsulation ratios if there is 14.4% polyvinyl alcohol or no aid. Furthermore, the effects which caused by treatment method should be considered. It was shown that only by using the hot water-ethanol-hot petroleum ether could remove the unencapsulated paraffin. In order to obtain microcapsules, the intermediate should have the capacities which could accumulate at the surfaces of the paraffin droplets. During the process of preparing paraffin microcapsules, the intermediate, which produced by condensation reaction between urea and formaldehyde, had a certain surface activity, moved towards the interface gradually, went on reacting and accumulating, then encapsulated the paraffin and produced microcapsules ultimately.