Mixed emulsifying agents

Summary

One per cent of aluminium hydroxide and bentonite was taken in suspension and their interfacial tension was determined with kerosene oil as dispersed phase byCenco-Du Noüy Interfacial Tensiometer No. 70545 after necessary calibrations and applying the correction factorF (9). Natural colloids (gum acacia, gelatin) and soaps were added into these suspensions in various concentrations and interfacial tension was determined. It was found that the addition of natural colloids, decreases the interfacial tension and the emulsions are finer and more stable. With the increasing quantities of these natural colloids to the suspensions, a further reduction in the interfacial tension is noticed, thereby such a corresponding emulsion formed has a higher interfacial area and stability factor. Similarly copper arsenate, lead arsenate, calcium arsenate and aluminium arsenate were taken and interfacial tension was measured with the addition of various quantities of natural colloids. The results arrived at, further show the lowering of interfacial tension with the conformity of finer emulsions having higher stability factors. Bordeaux mixtures, Burgundy mixtures, and copper phosphate were also taken and similar results were arrived at as shown in table 2 and 3.

The above facts reveal a relationship between sedimentation and interfacial tension; low interfacial tension to low sedimentation values represent greater wettabilities of the solids on the addition of colloidal solutions.

In this way was tested quantitatively the theory that the stability of an emulsion depends on relative interfacial tension and, as an approximate correlary, on the dispersibilities or wettabilities of the emulsifier in the two phases because whatever different causes may be operative in the stabilization of different emulsions, the one fundamental underlying principle applicable to all cases is the wetting of solid agent by the two liquids.