ABSTRACT
Carboxylic monomers are often employed in polymer formulations obtained by emulsion or miniemulsion polymerization with the aim of improve the better latex application properties. The aim of this work was to evaluate the effect of itaconic (IA), fumaric (FA) and methacrylic (MAA) acid on the emulsion copolymerization of styrene (STy) with n-butyl acrylate (ABu), aiming to obtain stable latexes with low concentration of poly(carboxylic acid) in the aqueous phase, to be used as cement additive. Latexes of STy/ABu/AI, STy/ABu/AF and Sty/ABu/AMA were obtained and characterized in relation to solids content, particle diameter, polydispersity, viscosity, minimum film forming temperature (TMFF), freeze-thaw stability, colloidal stability and distribution of the carboxylic groups. Cementitious mortar was prepared with the latexes and evaluated. The results obtained show that the type of carboxylic acid employed affects the physicochemical properties of latexes and the interaction with the components of the mortar. Among the acids studied, methacrylic acid had a lower effect on the colloidal properties of latexes. The latex produced with fumaric acid presented low colloidal stability, high concentration of carboxylic groups in the aqueous phase and low interaction with the components of the cementitious mortar.
Keywords
Emulsion polymerization; carboxylated latex; cementitious mortar; itaconic acid; fumaric acid
