Electrokinetic behavior of a poly(butyl acrylate-co-methacrylic acid) latex

Aqueous dispersions of poly(butyl acrylate-co-methacrylic acid) were obtained via emulsion polymerization of butyl acrylate and methacrylic acid, using sodium persulfate as the initiator and sodium dodecyl sulfate as the surfactant. Addition of HCl to the resultant dispersions resulted in the coagulation and addition of NaOH had as an outcome the decrease in values of zeta potential, without loss of stability. The decrease in zeta potential was correlated to the neutralization of carboxyl groups (and/or hydrolysis of acrylate ester groups) present on the dispersion particles, the neutralization being characterized through pH measurements and the presence of carboxyl groups using conductometric titration.