Effects of [beta]-cyclodextrin side chains on the dispersing and retarding properties of polycarboxylate superplasticizers

• Published in: Journal of applied polymer science 2012-07, Vol.125 (1), p.396-404
• Main Authors: Lv, Sheng-Hua, Gao, Rui-Jun, Duan, Jian-Ping, Li, Di, Cao, Qiang
• Format: Article
• Language: English
• Subjects: Calorimetry; Cements; Dispersions; Materials science; Pastes; Polymers; Retarding; Solvation; Superplasticizers; Viscosity
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.35606

A modified polycarboxylate (MPC) superplasticizer was synthesized by the copolymerization of acrylic acid, methallyl sulfonic acid, allyl poly(ethylene glycol)s, and [beta]-cyclodextrin ([beta]-CD) grafted maleic anhydride. The molecular structure of the MPC was characterized by Fourier transform infrared spectroscopy and gel permeation chromatography. The effects of the content of [beta]-CD on the application performance of MPC were investigated with measurements of the cement paste fluidity, setting time, amount of adsorption of MPC on the cement particles, and [zeta] potentials of the cement particles and differential scanning calorimetry-thermogravimetric analysis of different hydration ages of the cement pastes. The results indicate that the initial fluidities and setting times of the cement pastes increased with increasing number of [beta]-CD side chains. The dispersion capacity of MPC on the cement particles mainly came from a steric hindrance effect and an air-entraining effect of the [beta]-CD side chains. The better retarding performance of MPC was attributed to the solvation water film formed by the polyoxyethylene side chains and chelates formed by OH groups on the [beta]-CD structure combined with Ca2+ ions on the surface of the cement particles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [PUBLICATION ABSTRACT]