Effect of monomer partitioning on vinyl acetate-butyl acrylate emulsion copolymers

Abstract

Semi-continuous free radical emulsion polymerizations of vinyl acetate and butyl acrylate initiated by a water-soluble (potassium peroxydisulfate, KPS) initiator in the presence of a N-methylol acrylamide (NMA) at 70°C were investigated. 12 different monomer compositions (BuA ratio, from 0/100 to 100/0) were prepared and the effect of Vinyl acetate /Butyl acrylate (Vac/BuA) monomer ratio on viscosity, molecular weights (Mn, Mw, Mv), conversion, and molecular weight distribution were also investigated. It was found that as a protective colloid, N-methylol acrylamide worked perfectly for maintaining emulsion stability. Viscosity and molecular weights were increased with BuA ratio in the synthesized copolymers. High conversion values (above 90%) were reached. It was seen that the molecular weight distributions (PDI) of the synthesized copolymers showed a narrow distribution between 3-5.