Semibatch Emulsion Polymerization of Butyl Acrylate: Effect of Functional Monomers

Abstract

Abstract The concentration of sodium lauryl sulfate (SLS) in the initial reactor charge is the most important parameter in determining the latex particle size during semibatch emulsion polymerization of butyl acrylate in the presence of acrylic acid (AA), methacrylic acid, or hydroxyethyl methacrylate. The final latex particle size decreases with increasing concentration of SLS, NP-40, or functional monomer. The carboxylic monomer AA is the most efficient functional monomer to nucleate and then stabilize the latex particles. The plot of log N f vs log SLS shows a slope of 0.4–0.8, which is more consistent with Feeney's analysis based on the coagulative nucleation mechanism. Experimental data also show that the particle size first decreases to a minimum and then increases with an increase in the concentration of the neutralizing agent NaHCO3. The optimal concentration NaHCO3 for achieving the smallest latex particle size occurs at a point close to 0.15–0.29%. Experimental data of the particle size distribution and molecular weight distribution show that the aqueous phase reaction can play a very important role during the particle nucleation period.