Stability of monomer emulsion droplets and implications for polymerizations therein

The Lifshitz-Slezov-Wagner (LSW) theory of Ostwald ripening [I.M. Lifshitz, V.V. Slezov, Zh Exp Teor Fiz 35 (2(8)) (1958) 479-492; C.Z. Wagner, Elektrochemistry 65 (7/8) (1961) 581-591. [1], [2]] and Kabalnov's extension [A.S. Kabalnov, A.V. Pertzov, E.D. Shchukin, Colloid Surf 24 (1987) 19-32 [3]] is applied to theoretically analyze the stability of single and two component monomer emulsion drops (C1-monomer, C2-additional compound with low solubility in the continuous phase), respectively. The analysis is carried out for monomers frequently used in heterophase polymerizations such as methyl methacrylate (MMA), butyl acrylate (BA), styrene (STY), tert-butyl styrene (TBS), and lauryl methacrylate (LMA) and C2 with varied solubility in the continuous phase. Conclusions are drawn from the results regarding heterophase polymerizations carried out with such monomer emulsions. The calculations show that the solubility of both C1 and C2 in the continuous phase in combination with the concentration of C2 and the average emulsion drop size as well as the width of its distribution determines essentially the stability of emulsions.