Effect of Initial Polymerization Conditions on the Structure of Ethyl Acrylate-Methacrylic Acid Copolymer Latex Particles

Non-seeded semi-continuous emulsion copolymerizations of ethyl acrylate-methacrylic acid (85/15 wt. ratio) were carried out using various emulsifier and initiator concentrations and phase partitioning. The effect of the polymerization conditions on the particle size and morphology was investigated by means of scanning electron microscopy, light scattering and viscometry. Disintegration into smaller particles on alkali addition confirmed coagulative mechanism of the particle growth. This is distinct mainly if the colloidal stability of the polymerizing system is reduced due to lower concentration of the emulsifier and higher concentration of peroxydisulfate initiator which suppress double layer thickness of forming particles.