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

Abstract

A novel monovinyl β-cyclodextrin monomer (β-P) is employed to synthesize polycarboxylate superplasticizers with β-cyclodextrin (β-CD) grafted on the end of side chain [PAA-g-(β-P) n HPEG, n is the mass ratio of β-P in macromonomer, n = 3%~9%]. β-P is synthesized through grafting β-CD on the polyoxyethylene (PEO) via click reaction, which is the first try to superimpose the steric hindrance effect of PEO and β-CD during the preparation of polycarboxylate superplasticizer. FTIR, 1 H 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-(β-P) 7% HPEG has the largest fluidity; PAA-g-(β-P) 9% HPEG corresponds to the best fluidity retention performance; cement paste containing PAA-g-(β-P) n HPEG has shorter setting time. The DLS results reveal that the introduction of β-CD in PAA-g-(β-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.

Study on the dispersion performance and mechanism of polycarboxylate superplasticizer by the long side‐chain dicarboxyl terminated

“…The characteristic peaks at 35.5 and 37.5 ppm are corresponded to tertiary carbon (C8) and primary carbon (C9) in TA. In addition, the characteristic peaks of double‐bonded carbons (C2 and C3) were observed to disappear in the 13 C NMR spectra of PCE‐B and PCETA, indicating that the monomers were polymerized and the PCE was synthesized 39,40 …”

“…In addition, the characteristic peaks of double-bonded carbons (C2 and C3) were observed to disappear in the 13 C NMR spectra of PCE-B and PCETA, indicating that the monomers were polymerized and the PCE was synthesized. 39,40 Molecular properties of the synthesized PCEs were measured using the GPC. Figure 3 shows the GPC spectrum of PCETA-4000, and Table 2 shows the molecular parameters of 4 kinds of PCEs prepared after optimizing the acid-ether ratio.…”

Effect of chain transfer agents in polycarboxylate superplasticizer on slump‐retention of concrete

“…[ 1,2 ] PCEs are normally anionic polymers, using carboxyl groups as anchoring groups, and are adsorbed on positively charged mineral surfaces, such as those composed of C 3 A and C 4 AF. [ 3,4 ] The designable structure of PCE (the length of backbone and side chain, [ 5 ] adsorption groups, and spatial structure [ 6–8 ] ) endows polymers with various preferential properties arising from specific microstructures. Many types of PCE have been discovered for concrete systems, such as high water‐reducing rate, slump‐retention, [ 9 ] early‐strength, [ 10 ] viscosity‐reducing, [ 10–13 ] and shrinkage‐reducing.…”