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Optimization of comb‐shaped polycarboxylate cement dispersants to achieve fast‐flowing mortar and concrete
Authors:Alex Lange  Johann Plank
Affiliation:Technische Universit?t München, Chair for Construction Chemistry, Garching, Lichtenbergstra?e 4, Germany
Abstract:
Concretes and mortars possessing a low water‐to‐cement (w/c) ratio (<0.40) liquefied with comb‐shaped polycarboxylate (PCE) copolymers commonly exhibit a sticky, honey‐like consistency, and slow flow behavior. The stickiness is owed to high plastic viscosity of the suspension. In this study, different PCE comb polymers based on methacrylate ester, allyl, vinyl, and isoprenyl ether macromonomers were synthesized and analyzed. It was found that their hydrophilic–lipophilic balance (HLB) value, i.e., the balance between the hydrophilic and lipophilic parts in these PCE molecules determines their effect on the plastic viscosity of a concrete. PCE copolymers mainly composed of hydrophilic parts, i.e., such possessing high HLB values, impart low plastic viscosity. Allyl ether—maleic acid based PCEs exhibit especially high HLB values and thus impart low plastic viscosity. Higher viscosities were recorded for isoprenylether PCEs, while methacrylate‐ester and vinyl ether PCEs possess particularly low HLB values and hence produce a pronounced sticky concrete. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42529.
Keywords:adsorption  copolymers  hydrophilic polymers  plasticizer  rheology
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