Study of the spinnability of emulsions based on a two-phase water-casein-sodium alginate system

The spinnability of emulsions basing on a two-phase water—casein—sodium alginate system (pH 7.2) was studied as a function of the compositions of the co-existing phases and of the ratio of their volumes by measuring the maximum fiber take-up velocity. It has been established that the spinnability of the emulsion is practically independent of the compositions of the co-existing phases. The dependence of the spinnability of the emulsion on the ratio of the volumes of the phases can be illustrated by an S-shaped curve: except for the phase inversion region, the spinnability of the emulsion is determined by the spinnability of the continuous (matrix) phase, and in the phase inversion region, changes sharply from one constant level to another. A 2.2 % solution of sodium alginate was spun through spinnerets of different channel diameters at constant linear extrusion rate. It was shown that a variation of the jet cross section has no effect on the maximum fiber take-up velocity. On this basis it was assumed that beyond the phase inversion region the effect of the content of the disperse phase on the spinnability of the emulsion is equivalent to a change in the effective cross section of the matrix phase. The universal character of these assumptions has been confirmed by experiments in spinning of a silicone oil/sodium alginate solution emulsion.