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 ? potentials of the cement particles and differential scanning calorimetrythermogravimetric 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. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012