负离子粉表面改性方法与聚合物包覆性能研究

目的 比较三种不同改性方法对负离子粉表面改性的效果.方法 以KH-570为改性剂,分别采用球磨法、溶剂回流法和干研磨法对超细负离子粉进行表面有机化改性.将改性后的负离子粉分散到丙烯酸酯单体中,通过悬浮聚合在负离子粉表面生成聚合物包覆层,并制备成包含负离子粉的聚合物微球体.通过7230G分光光度计对比粉体在甲基丙烯酸甲酯单体中的悬浮性能.采用扫描电镜观察粉体的形貌特征以及聚合物包覆后粉体表面与聚合物的结合状况.分离出未被聚合物包覆的负离子粉,计算负离子粉的有效包覆率.采用COM-3010PRO负离子测试仪测试聚合物包覆前后负离子的释放性能.通过综合对比和分析,判断改性方法的优劣.结果 三种改性方法都可以实现对负离子粉表面的有机化改性.负离子粉表面有机化改性后,平均粒径减小,在甲基丙烯酸甲酯中分散悬浮稳定性明显增加.通过悬浮聚合可以得到聚合物包覆的负离子粉体微球,负离子粉在聚合物中分布均匀、结合牢固,聚合物有效包覆率最高可达79.2％.从改性后负离子粉的悬浮稳定性、聚合物包覆率、在聚合物中的分布状态以及负离子释放性能等方面,均体现出球磨法最优,溶剂回流法次之,干研磨法最差的规律.结论 球磨法是最佳的处理方法,负离子粉在聚合物中分布均匀,聚合物有效包覆率高,负离子释放量大.

Study on Surface Modification of Negative Ion Powder and the Polymer Coating Performance

This paper aims to probe the impact of different methods upon the surface modification of the negative ion powder. Using KH-570 as the modifier, the surface organic modification of the ultrafine negative ion powder is conducted by three methods, including ball milling, solvent reflux and dry milling. The coating of PMMA on the surface of the pre-treated negative ion powder is carried out through suspension polymerization, by dispersing the negative ion powder in MMA monomer, yielding the negative ion powder containing polymeric microsphere. The suspension performance of the powder in MMA monomer is compared using 7230G spectrophotometer; The morphology of the powder and the binding of the powder and the polymer are characterized by SEM; The effective coating rate is calculated by isolating the negative ion powder that is not coated; The release performance before and after polymer coating is tested through COM-3010PRO negative ion detector. The three modification methods are then compared after comprehensive comparison and analysis. The surface organic modification of the negative ion powder can be successfully carried out by all the above three methods; The average particle size of the negative ion powder decreases upon surface modification, which enhances the dispersion stability of the negative ion powder in MMA. The polymer coated negative ion powder can be yielded through suspension polymerization. The negative ion powder can homogeneously distribute in polymer and bind firmly with the polymer. The effective coating rate of the polymer can reach up to 79.2%. After comparing the dispersion stability, polymer coating rate, distribution status and the negative ion powder release performance of the negative ion powder, it concludes that the three modification methods follow the trend:ball milling, solvent reflux, dry milling. The most effective modification method is ball milling. It ensures the homogeneous dispersion of the negative ion powder in the polymer, the high polymer coating rate and high negative ion release amount.