Effects of submicron core-shell latexes with different functional groups on the adsorption and cement hydration

The type of functional groups equipped on surface of colloidal particles is a dominant factor determining the impacts of polymer latexes on the properties of cement-based materials. In this study, two kinds of polymer latexes separately assembled with acrylic acid (AA) and 2-acrylamico-2-methyl propane sulfonic acid (AMPS) were incorporated into oil well cement as chemical additives. Their effects on hydration and mechanical properties of cement-based materials as well as mechanism were investigated and compared. The results show that polymer latexes with different functional groups present different adsorption behaviors and retardation effects in cementitious systems. These two latexes both retard the cement hydration but to different extents. Compared with the polymer latex modified with -SO3-, the latex assembled with -COO- exhibits a stronger retardation effect. This phenomenon can be attributed to the higher adsorption capability of -COO- on mineral surface as well as the stronger chelation effect formed by Ca2+ and -COO-. (c) 2018 Elsevier Ltd. All rights reserved.