溶剂对水性丙烯酸分散体及涂层性能的影响

Effect of solvent on the properties of waterborne acrylic acid dispersion and coating

在聚合反应中,溶剂不仅具有控制聚合物的相对分子质量与分布、溶解单体的作用,以及优异的降黏效果,而且可增加树脂透明度及提高漆膜性能。因此,研究溶剂在聚合反应中的作用效果非常必要。采用无皂乳液聚合与溶液聚合的复合技术合成水性丙烯酸分散体,考察了溶剂种类、溶剂比例、以及溶剂含量对水性丙烯酸分散体及涂层性能影响。结果表明,溶剂主要对水性分散体黏度、涂层干性、耐水性及力学性能影响较大。确定最佳溶剂为二乙二醇丁醚/乙二醇叔丁基醚(DB/ETB)混合溶剂,质量比为5∶5,溶剂含量为11%。在该条件下合成的水性丙烯酸分散体粒径较小且分布较窄,平均粒为242.8nm。红外测试结果表明,单体已基本聚合完全。热重分析结果表明,水性丙烯酸分散体在430℃左右时基本分解完全,热稳定性良好。

In the polymerization reaction,the solvent can not only control the relative molecular weight and distribution of the polymer,dissolve the monomer and reduce the viscosity,but also increase the transparency of the resin and improve the performance of the paint film.Therefore,it is very necessary to study the effect of solvent in polymerization reaction.Waterborne acrylic acid dispersion was synthesized by soap free emulsion polymerization and solution polymerization,and the effects of solvent type,solvent proportion and solvent content on the properties of waterborne acrylic acid dispersion and coating were investigated.The results showed that the solvent mainly affected the viscosity of the waterborne dispersion,the dryness,water resistance and mechanical properties of the coating.The optimal solvent was DB/ETB mixed solvent,with a mass ratio of 5∶5 and a solvent content of 11%.The waterborne acrylic acid dispersion synthesized under this condition had a small particle size and narrow distribution,with an average particle size of 242.8nm.The results of IR showed that the monomer had been polymerized completely.Thermogravimetric analysis indicated that the waterborne acrylic acid dispersion basically decomposed completely at about 430℃and had good thermal stability.