The effect of micelles with random pH-sensitive/hydrophobic structure on the workability, hydration process and microstructure of cement paste. Issue 28 (17th March 2017)

• Record Type: Journal Article
• Authors: Zhu, Y. Y.; Hu, J.; Ma, Y. W.; Xie, H. B.; Guo, W. H.; Wei, J. X.; Yu, Q. J.
• Is Part Of: RSC advances. Volume 7:Issue 28(2017)
• Page Start: 17085
• Page End: 17094
• Publication Date: 2017-03-17
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra26643f
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : In this study, micelles with pH sensitive/hydrophobic structure efficiently affected the workability, hydration and microstructure of cement paste. The mechanisms are related to the nucleation effect, molecular structure and adsorption of micelles. Abstract : In this study, the workability, hydration rate and microstructure of cement paste in the presence of the micelles prepared by two different diblock copolymers with random pH sensitive/hydrophobic structure (poly(polylactide methacrylate- co-tert -butyl methacrylate)- b -poly(poly(ethylene glycol) methyl ether methacrylate) (P(PLAMA- co -tBMA)- b -PPEGMA) and poly(ethylene glycol) methyl ether- b -(poly-lactic acid- co -poly(β-amino esters)) (MPEG- b -(PLA- co -PAE)) copolymers, respectively) were investigated. In fresh cement paste, the micelles were efficiently adsorbed on cement particles; although the average zeta potential of cement particles was not significantly changed in the presence of the micelles due to their low concentrations, with a high water to cement ratio, the adsorbed micelles altered the zeta potential of partial cement particles, leading to a better workability of cement paste. In hardened cement paste, the micelles retarded the hydration rate of C3 S at very early hydration age, but accelerated the hydration rate of cement paste at later stages, resulting in a denser cement matrix and increased mechanical property. The most plausible mechanisms are related to the nucleation effect, molecular structure and adsorption performance of the polymeric micelles.