Synthesis and performance of a novel polycarboxylate superplasticizer through grafting the β-cyclodextrin on the side chain by click reaction

A novel monovinyl beta-cyclodextrin monomer (beta-P) is employed to synthesize polycarboxylate superplasticizers with beta-cyclodextrin (beta-CD) grafted on the end of side chain [PAA-g-(beta-P)(n)HPEG, n is the mass ratio of beta-P in macromonomer, n = 3% similar to 9%]. beta-P is synthesized through grafting beta-CD on the polyoxyethylene (PEO) via click reaction, which is the first try to superimpose the steric hindrance effect of PEO and beta-CD during the preparation of polycarboxylate superplasticizer. FTIR, H-1 NMR, GPC, and DLS are used to characterize the molecular structure of the intermediates and the products. Compared with PAA-g-HPEG (PCE0) only with PEO as side chains, cement paste containing PAA-g-(beta-P)(7%)HPEG has the largest fluidity; PAA-g-(beta-P)(9%)HPEG corresponds to the best fluidity retention performance; cement paste containing PAA-g-(beta-P)(n)HPEG has shorter setting time. The DLS results reveal that the introduction of beta-CD in PAA-g-(beta-P)(n)HPEG extends the side chain length and increases the steric hindrance effect. The adsorption test results show that the novel PCE has good slump retention performance because it is adsorbed on cement particles less but more lives in the liquid phase with the n increasing. This study provides a new approach to synthesize high-performance polycarboxylate superplasticizer.