Zeta电位法选择农药悬浮剂所需润湿分散剂

采用Zeta电位法对质量分数为20%的吡氟草胺悬浮剂所需润湿分散剂进行筛选,以激光粒度分布仪对实验体系的平均粒径(Dav)进行了验证。研究结果表明,除木质素磺酸钠以外,阴离子型润湿分散剂均可使体系的Zeta电位绝对值(│ζ│)达到40mV以上,体系较为稳定;阴离子型润湿分散剂NNO和MorwetD425复配后,相同使用量下体系的│ζ│较单一使用NNO和MorwetD425的大;当m(NNO):m(MorwetD425)=1:4,复配润湿分散剂的总质量分数为1%时,│ζ│达到最大值,颗粒平均粒径最小,热贮前后变化很小,体系达到最佳分散效果。因此,Zeta电位表征润湿分散剂在农药悬浮剂中的润湿分散性能与体系颗粒平均粒径的变化规律有良好的对应关系,故Zeta电位可作为表征润湿分散剂分散性能优劣的指标。

Selection of Wetting Dispersant in Pesticide Suspension Concentrate with Zeta Potential Method

Zeta potential method was used to select wetting dispersant in preparing 20% diflufenican suspension concentrate, the average particle diameter(Dav) of test system was determined using a laser particle distribution instrument. The results show that all test anionic wetting dispersants, beside sodium lignosulfonate, could make the suspension particle to reach the absolute value of Zeta potential(│ζ│) in excess of 40 mV, and the suspension concentrate was comparatively stable. When mixed anionic wetting dispersants(NNO and Morwet D425) were used instead of single NNO or Morwet D425, │ζ│ of the suspension system was higher than that of single system at the same usage amount. When m(NNO)∶m(Morwet D425)=1∶4, and mass fraction of the mixture was 1%, │ζ│ could reach the maximum and the average particle diameter of the system was the smallest. The changes of │ζ│ and Dav were very small after heat storage treatment, and the corresponding system achieved the best dispersion effect. Thus zeta potential value of the suspension concentrate has a good correlation to the average particle diameter. Therefore the dispersing effect of wetting dispersant in suspension concentrate could be well represented by the zeta potential value.