Effect of water-soluble cross-linker on the growth and properties of ethylacryrate-methacrylic acid emulsion copolymer particles

Model ethyl acrylate-methacrylic acid copolymer latices and latices of part icles cross-linked by copolymerizing small amounts of water-soluble N,N'-me thylenebisacrylamide were prepared by nonseeded semicontinuous emulsion cop olymerization. Dynamic and static light scattering measurements indicated a slightly higher degree of polydispersity in the case of crosslinked partic les, especially in the initial stages of polymerization. The hydrodynamic v olume of the alkalinized particles controlling the viscosity properties of the dispersions decreased with the time of polymerization and in the case o f crosslinked copolymer almost reached a constant value at about 1 h. The d ifferent character of the particle structure was confirmed by differences i n particle disintegration after alkali addition or in the presence of metha nol.