Effect of styrene and methyl methacrylate comonomers in ethyl acrylate/methacrylic acid latex on particle alkali-swellability, film formation and thickening with associative thickeners

Series of emulsion copolymers were synthesized from methacrylic acid, ethyl acrylate as a “soft” comonomer and different amounts of methyl methacrylate or styrene as “hard” comonomers. It was shown that the extent of particle swelling and hydroplasticization at constant content of methacrylic acid was affected by the “hard” comonomer content due to its polarity. The minimum film forming temperature (MFT) results were found to be in good agreement with the titration curves, with zeta-potential measurements and with the flow behavior of the copolymer latices. Viscosity increase caused by particle swelling strongly influences thickening of latex material also being dependent on the comonomer polarity.