Hydrolysis of Dimethyl Meta-Isopropenylbenzyl Isocyanate (TMI) and Colloidal Stability of Latexes During Storage: Effect of pH

The hydrolysis of the isocyanate (NCO) group of dimethyl meta-isopropenylbenzyl isocyanate (TMI) and colloidal stability of terpolymer latexes during storage at different pH were studied. These latexes were prepared at 40°C by batch emulsion polymerizations using vinyl acetate (VAc), butyl acrylate (BA) and TMI as monomers and Aerosol A-103 as surfactant. The TMI content was calculated in the poly(VAc-BA-TMI) latex at the end of the polymerization and also monitored during storage (at room temperature). It was found that the hydrolysis of the NCO group of the TMI and the colloidal stability of the latexes were affected to different extents by the pH value. The feasibility that the other chemical groups formed by hydrolysis of the VAc and BA units in the latexes during storage could promote these phenomena is discussed.