阳离子聚丙烯酰胺微乳液的制备及其絮凝性能研究

以甲醛、二甲胺和丙烯酰胺为原料,通过Mannich反应首先合成阳离子单体N-(二甲氨基)甲基丙烯酰胺,然后用反相微乳液聚合制得不同阳离子度的阳离子聚丙烯酰胺乳液(CPAM).通过探讨反应过程的影响因素,确定了最佳的制备工艺,并对制成的产品进行了性能研究.当反应温度50℃,物质的量比n(丙烯酰胺)∶n(甲醛)∶n(二甲胺)=1∶1.2∶1,反应时间为2 h时,制备的阳离子单体可使乳液聚合的产品获得最佳的阳离子度.通过正交实验反映了单体质量分数、引发剂质量分数、油水相体积比以及反应温度对聚合反应的影响.结果表明,当单体质量分数为30%,引发剂质量分数为0.8%,油水相体积比1.2∶1,反应温度40℃时产品的絮凝效果最佳.在常温、酸性条件下,CPAM对硅藻土的絮凝效果良好.

Preparation of cationic polyarylamide microemulsion and study on its flocculation performance

The cationic monomer of N-(dimethylamino) methyl acrylamide is synthesized using formaldehyde,dimethylamine and acrylamide first.Then, the cationic polyacrylamide latexes(CPAM) with different cationic degrees are prepared by reversed phase emulsion polymerization.The preparation conditions are optimized.And,the flocculation performance of the products is also studied. The best preparation conditions of the cationic monomer are: the reaction temperature is 50 ℃,the molar ratio of acrylamide to formaldehyde to dimethylamine is 1:1.2:1,and the reaction time is 2 h.And,the best cationic degree of the polyacrylamide latex is achieved under the above optimum conditions.The effects of the dose of the monomer,the dose of the initiator,the ratio of oil to water phase and the reaction temperature on the polyreaction are studied by the orthogonal experiments.The results show that the product can achieve the best flocculating result under the conditions of the monomer concentration of 30%,the initiator dose of 0.8%,the ratio of oil to water phase of 1.2:1 and the reaction temperature of 40 ℃.CPAM has the better flocculating effect on diatomaceous under normal temperature and sour environment.