Dispersion and weak retardation performance of sulfate-based starch maleic acid monoesters in cement

To reduce the influence of a sulfate-based starch water-reducing agent on the setting time of cement, a novel starch-based water-reducing agent, namely sulfate-based starch maleic acid monoester (SAMAS), was designed to adjust its hydrophilicity by maleic acid monoester. Gel permeation chromatography, Fourier transform infrared spectroscopy, and 1H NMR nuclear magnetic resonance spectroscopy were used to characterize the prepared SAMAS, while Zeta potential, UV-Vis absorption, X-ray photoelectron spectroscopy, X-ray diffraction, cement paste fluidity, and setting time measurements were conducted to investigate its dispersion performance, retardation performance, adsorption behavior, and mechanism of action. SAMAS exhibited good dispersion performance and did not significantly prolong the setting time of the cement. In addition, the dispersion performance of SAMAS was found to depend mainly on steric hindrance, and its weak retardation performance originated from the hydrophilic regulation of the maleic acid monoester groups, which ensures the normal progress of the cement hydration reaction by hindering the formation of a hydration film.