Role of PVOH and kaolin on colloidal stability of liquid and powder EVA and SB latexes in cement pore solution

Retardation effect of styrene-acrylate copolymer latexes on cement hydration

“…They concluded that the 'catching of the Ca 2+ ions' in acrylate polymer should be responsible for the strong retardation effect of acrylate latexes [19]. The strong interaction between Ca 2+ ions and polymer particles possessing carboxylate functionalities due to the complexation effect has been confirmed by many studies [18,27,28,38,39]. The concentration of Ca 2+ ion in pore solution of a hydrating cement pastes can be greatly influenced by addition of polymer latexes containing carboxylate functionalities.…”

“…The interstitial solution of freshly mixed cement paste is separated from the mixture by centrifuging at 4000 rpm, which is sufficient for separation of cement grains from the aqueous phase, but is not high enough to separate polymer particles from the aqueous phase. For the blank paste, the supernatant liquid after centrifuge appears colorless and transparent, which contains various salts due to the initial dissolution of cement clinkers [27]. With addition of latex in cement paste, the supernatant liquid is still colorless and transparent at low dosage of polymer, indicating that the added polymer particles are almost completely adsorbed by cement grains.…”

“…Therefore, it is of great importance to scientifically understand the mechanism of polymer latexes in influencing the cement hydration process. Atkins et al demonstrated that the acrylic based polymers are partially hydrolyzed in cementitious environment and thus have marked retardation effect on cement Cement and Concrete Research 75 (2015) [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] hydration [13]. On the other hand, Su proposed that the suppression of hydration by acrylate based polymers is partly due to the adsorption of polymer on cement grains and in part, due to the reaction of Ca 2+ ions with polyelectrolytes.…”

Influence of carboxylated styrene–butadiene latex copolymer on Portland cement hydration

“…Its phase composition as determined by quantitative X-ray diffraction (Bruker AXS D8 Advance, Karlsruhe, Germany) using Rietveld refinement (software Topas 4.0) is shown in Table 1. Particle size, zeta potential, anionic charge density, glass transition temperature (T g ) and minimum film forming temperature (MFFT) of the liquid and powder SB samples were determined as described in a previous paper [7]. …”

“…kaolin), diatomaceous earth, microsized silica or calcium carbonate serve as anti-caking agents. In a previous study, we have reported about the effects of the spraying aids PVOH and kaolin on the colloidal properties of carboxylated SB and ethylene-vinyl acetate latexes [7]. They increase the colloidal stability of the re-dispersed latex powder and promote its film formation.…”