Abstract:

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.

Key words: Zeta potential, suspension concentrate, wetting dispersant, diflufenican