CUPRIC SULFATE-HYDRAZINE-OXYGEN SYSTEM AS AN INITIATOR FOR EMULSION POLYMERIZATION OF METHYL METHACRYLATE

The kinetics of the emulsion polymerization of methyl methacrylate initiated by the cupric sulfate‐hydrazine system in the presence of oxygen have been evaluated. A maximum rate of polymerization occurs at a cupric sulfate concentration of 1.8 × 10−4 mole liter−1. The adsorption of cupric ion on the micelles and the adsorption of soap on cupric hydroxide are discussed as an explanation of this effect. A reaction between hydrazine and methyl methacrylate produces a surface active agent which enhances the rate of polymerization and increases the number of particles at high ratios of monomer concentration to soap concentration. The kinetics follow the mechanism of Gershberg rather than that of Smith and Ewart, and the initiation of the emulsion polymerization appears to take place inside the micelle rather than in the aqueous phase as was proposed by van der Hoff for styrene. The activation energy for the complete process is 23.7 kcal mole−1. Copyright © 1969 John Wiley & Sons, Inc.