Emulsion terpolymerization of dimethyl meta-isopropenyl benzyl isocyanate (TMI�) with acrylic monomers: Process development and kinetics

Abstract

Dimethyl meta-isopropenyl benzyl isocyanate (TMI®) is a bifunctional monomer possessing a double bond and an isocyanate group. Emulsion terpolymerization of TMI with the acrylic monomers, methyl methacrylate and n-butyl acrylate, was studied. Polymerizations were carried out at 40°C using a redox initiator system in order to minimize the extent of hydrolysis of the isocyanate in the aqueous emulsion environment. The kinetics of the polymerization reaction were investigated. The polymerization rate was found to decrease with increasing TMI concentration. The effects of several preparative variables such as the monomer, surfactant, and initiator concentration on the polymerization kinetics was studied. Several semicontinuous polymerization processes were developed in order to enhance the incorporation of TMI at appreciable rates. These processes also allow us to control the polymer composition, latex particle size, and the locus of isocyanate groups in the latex particle. Process variables such as the mode of initiator addition (batch versus semicontinuous) were found to greatly influence the polymerization behavior. © 1996 John Wiley & Sons, Inc.