Abstract
Thickening of lattices of styrene–acrylic copolymers containing a small amount of acrylic acid and various amounts of 2-hydroxyethyl methacrylate (HEMA) with alkali-swellable dispersion of crosslinked ethyl acrylate/methacrylic acid copolymer has been studied using capillary viscometry and dynamic and steady shear measurements. The higher the amount of HEMA incorporated into the latex copolymers, the stronger the thickening effect is. A comparison of flow behavior of thickened systems with those of neat lattices confirmed a significant influence of the effective volume fraction of alkalinized swollen latex particles on the thickening process. Under these conditions, to obtain the same rheological properties, the necessary amount of thickener was lower for the latex copolymers with higher amounts of HEMA because a part of the thickener volume fraction was replaced by an increased volume fraction of swollen latex particles. These findings indicate weakly interacting dispersion systems without strong compression of particle domains.