IRON(II)-CHLORIDE CATALYZED EMULSION POLYMERIZATION OF METHYL-METHACRYLATE USING DIFFERENT INITIATORS

The emulsifier and emulsifier-free emulsion polymerization of methyl m ethacrylate (MMA) using sodium bisulphite, acetaldehyde sodium bisulph ite (ACSB), octyladehyde sodium bisulphite (OSB), benzaldehyde sodium bisulphite (BSB), and acetone sodium bisulphite (ASB) as different ini tiators, and dodecyl benzene sodium sulphonate (DBSS) as an emulsifier , were carried out at 30, 40, and 50 degrees C. The effect of iron (II ) chloride on the rate of polymerization and on the viscosity-average molecular weight was investigated. The effect of temperature, iron (II ) chloride, and the type of initiator on the tacticity of the obtained polymers was investigated by means of nuclear magnetic resonance (NMR ) spectroscopy. The effect of iron (II) chloride and the four carbonyl adducts (ACSB, OSB, BSB, and ASB) on the volume-average diameter and the number of polymer particles per unit volume was investigated. It w as found that iron (II) chloride has a pronounced catalytic effect on the emulsion polymerization. The initiating powers of the four carbony l adducts, ACSB, BSB, OSB, and ASB, were found to be 3.27, 0.6, 1.78, and 0.23, respectively. The rate of emulsion polymerization and viscos ity-average molecular weight were found to be dependent on the emulsif ier concentration, initiator type and concentration, temperature, and amount of the catalyst (FeCl2). (C) 1998 John Wiley & Sons, Inc.