The Coagulation Mechanism of Butadiene—Styrene Latex

Abstract

1. It is shown that the absolute values of the coagulation thresholds of SKS-30A latexes diluted down to 0.01% correspond to the usual values for lyophobic sols. The values for NaCl are 200 times those for CaCl2, and increase with the latex concentration. The complete coagulation concentration for NaCl is 30 times that for CaCl2, and does not depend on the dilution of the latex. 2. It was shown by a nephelometric method that the volume of the primary particles formed in coagulation of the latex by sodium chloride is about 10 times the volume of the uncoagulated latex globules, irrespective of the latex concentration. 3. Consideration of the experimental data, in conjunction with facts reported in the literature, leads to the concept of two stages in the coagulation of latex by electrolytes: the first is the consequence of a decrease of the zeta potential, leading to the formation of primary particles, and the second leads to coalescence of these particles. The secondary aggregation processes can be prevented or modified by introduction of certain additives (nonelectrolytes) into the latex. 4. In additon to an explanation of the mechanism of latex coagulation by electrolytes, and a demonstration that this process can be controlled, indications are given of means of an approach to development of conditions for the production of a good blanket by coagulation of latex by sodium chloride, with a much decreased consumption of the latter.

Effect of Calcium Chloride as a Coagulant on the Properties of ESBR/Silica Wet Masterbatch Compound

“…The latex shows basicity (pH 9~10) due to the OH anion from KOH used in the saponification of emulsifier. By the addition of coagulant into the latex, coagulation will be started [23,24,25]. Coagulation mechanism is shown in Figure 1.…”