High- and low-molecular-weight lignosulfonates and Kraft lignins as oil/water-emulsion stabilizers studied by means of electrical conductivity

Electrical conductivity measurements were used to study the creaming rates in oil/water emulsions stabilized with five lignosulfonates and one Kraft l ignin. The creaming process resulted in a narrow dispersion band separating the water-rich and the oil-rich phases. An electrode was designed to follo w this zone in the emulsion as a function of time. This makes it possible t o calculate the amount of water separated from the emulsion directly from t he creaming profiles. The stability concerning creaming was also evaluated with data obtained from visual inspection. Equivalent creaming profiles ind icate that the electrode design used is suitable for stability measurements in the systems examined. Droplet interaction in diluted emulsions was stud ied with video-enhanced microscopy.