表面活性剂对微细滑石的分散作用

Dispersion effect of surfactant on ultrafine talc

采用沉降法考察了阳离子表面活性剂和几种亲水基不同的阴离子表面活性剂在水介质中对微细滑石颗粒的分散效果；通过测试加入表面活性荆前后颗粒表面Zeta电位、体系分散率变化，探讨了分散剂的作用机理。研究结果表明：阳离子表面活性荆对微细滑石粉体的分散效果不佳；含有强亲水性的磺酸基团和羧酸基团的阴离子表面活性剂对滑石粉体具有一定的分散效果；加入表面活性剂使颗粒表面Zeta电位绝对值变大，提高了悬浮液的稳定性。表面活性荆的最佳浓度分别为：月桂酸钠，2×10^-5mol／L;十二烷基苯磺酸钠，4×10^-5mol／L；合适的pH值范围为10．5～11．5；表面活性剂通过增大静电斥力和空间位阻起分散作用。

The dispersion behavior of ultrafine talc in aqueous system was investigated by the sedimentation test. The dispersion effects of cationic surfactant and some anionic surfactants with different hydrophilic ionogens were studied. By testing the changes of Zeta potential and the dispersion rate of the system with the addition of surfactant, the dispersion mechanism of dispersants was discussed. The experimental result reveals that cationic surfactant is poor on the stability of dispersion. But anionic surfactants with better hydrophile ionogen of benzene sulfonic acid and carboxylic acid are the effective dispersants for talc. The addition of surfactant can increase the absolute value of Zeta potential and improve the stability of suspension. The optimum concentrations of sodium laurate and sodium dodecy benzene sulfonate are 2 ×10^-5 mol/L, and 4 ×10^-5 mol/L respectively, and the suitable pH value is 10.5 - 11.5. The hydrophobic interaction on the surface of particles controls the dispersion and coagulation of particles and the main effect of dispersants is to increase the electrostatic force.