Preparation and characterization of poly-carboxymethyl-β-cyclodextrin superplasticizer

Lv, Shenghua; Gao, Ruijun; Cao, Qiang; Li, Di; Duan, Jianping

doi:10.1016/j.cemconres.2012.06.006

Cited by 48 publications

(30 citation statements)

References 24 publications

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“…[4] However, in this article in order to obtain copolymers with mild retarding performance, new ternary copolymers (PTCDs) of AA, TPEG, and GCD were designed and synthesized. The effects of PTCDs on the setting times of the cement pastes were studied at a superplasticizer dosage of 0.2 wt% and a W=C of 0.29.…”

Section: Setting Times and Retarding Effectmentioning

confidence: 99%

“…The success of these polymers is attributed to certain unique qualities they are known for, such as reducing the amount of freshwater used in the production of concrete, improving the quality of concrete, obtaining specified strength at lower cement content, and improving the properties of concrete-containing marginal-or low-quality aggregates. [1][2][3][4][5][6][7][8] In recent years, much attention has been directed toward the design and construction of superplasticizers or high-range water reducers. Among these superplasticizers, polycarboxylate superplasticizers (hereinafter called PCEs) have been investigated since the 1980s.…”

Section: Preparation and Application Of New Polycarboxylate Superplasmentioning

confidence: 99%

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Preparation and Application of New Polycarboxylate Superplasticizers with Mild Retarding Performance Based on Monovinyl β-Cyclodextrin Monomer

Zheng

Guo

et al. 2014

Journal of Dispersion Science and Technology

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Based on monovinyl b-CD monomer (GCD), random copolymers (PTCDs) were first synthesized by AA, TPEG, and GCD, and characterized by FTIR and GPC. The application performances of PTCDs as superplasticizers in cement and concrete were investigated considering dispersion, adsorption, setting times, and compressive strength. The results indicated that PTCDs had more excellent applied performance compared with AA-co-GCD copolymers, and the outstanding feature is that PTCDs had a mild tunable retarding effect. When with certain amount of CD pendants and PEO side chains, PTCD 2 had the best dispersion and mild retarding performances, which were mainly attributed to the joint steric hindrance effect provided by CD pendants and PEO side chains. This study offers a new type of superplasticizer from CD and its derivatives with excellent dispersion and retarding performances to concrete engineering.

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Section: Setting Times and Retarding Effectmentioning

confidence: 99%

Section: Preparation and Application Of New Polycarboxylate Superplasmentioning

confidence: 99%

Preparation and Application of New Polycarboxylate Superplasticizers with Mild Retarding Performance Based on Monovinyl β-Cyclodextrin Monomer

Zheng

Guo

et al. 2014

Journal of Dispersion Science and Technology

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“…Based on this, the retarder might hinder the adsorption process of PCE and it was referred to as competitive adsorption [31][32][33][34][35], thereby reducing the dispersion. In addition, the thickness of the adsorption layer should also be accepted as a factor influencing the dispersion of PCE [36,37]. In spite of the decline in adsorption amount of PCE in the presence of retarder, as reported in previous study, the adsorption layer was obviously thickened to enhance the dispersion [37].…”

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confidence: 74%

Effect of Sodium Hexametaphosphate and Trisodium Phosphate on Dispersion of Polycarboxylate Superplasticizer

Zhang

Liu

et al. 2019

Materials

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Enhancement in dispersion of polycarboxylate superplasticizer (PCE) could be obtained by incorporating retarders in normal concrete. The generally believed reason was that the consumption of free water and polymer at the beginning was reduced by retarding cement hydration. This theory could not convincingly explain why sodium hexametaphosphate (SHMP) was able to promote the dispersion capacity of PCE, while trisodium phosphate (TSP) could not, despite that both TSP and SHMP could obviously retard the cement hydration. The adsorption behavior of PCE and phosphate was investigated and the mechanism was analyzed in order to gain deeper understanding. The results showed that TSP and SHMP delayed the cement hydration, impeded adsorption process of PCE, and increased thickness of adsorption layer. It was interesting that TSP reduced the dispersion, but SHMP enhanced. The reason for this contradiction was due to the difference in composition of adsorption layer. In the PCE-TSP system, this layer was composed of the precipitates (formed by TSP and Ca 2+ ) and the invalided PCE (caused by these precipitates in the immediate vicinity of the cement grains); the invalided PCE was due to the decrease of PCE dispersion. In the PCE-SHMP system, "Inner-phosphate (multi-layers) + Outer-PCE (single layer)" structure was formed to make the PCE work more effective, hence enhancing the dispersion. These results were expected to be useful for the design of highly efficient dispersants. dispersion capacity [26][27][28][29][30]. Based on this, the retarder might hinder the adsorption process of PCE and it was referred to as competitive adsorption [31][32][33][34][35], thereby reducing the dispersion. In addition, the thickness of the adsorption layer should also be accepted as a factor influencing the dispersion of PCE [36,37]. In spite of the decline in adsorption amount of PCE in the presence of retarder, as reported in previous study, the adsorption layer was obviously thickened to enhance the dispersion [37]. On the basis of discussion above, the conclusion could be made that the dispersion capacity of the PCE-retarder system should be associated with the retarding effect of retarder, adsorption behavior of PCE, and the thickness of the adsorption layer.Poly-phosphates, such as sodium tripolyphosphate and sodium hexametaphosphate (SHMP), have been widely used to promote the dispersion ability and dispersion retention ability of the superplasticizer system in real engineering practice. However, mono-phosphates, such as trisodium phosphate (TSP) and sodium hydrogen phosphate, cannot play the same roles as poly-phosphate in commercially available PCE products. If the retardation was the main reason for the enhancement, poly-phosphate and mono-phosphate would both have a similar effect on dispersion of PCE system, because both TPS and SHMP could retard the cement hydration [38]. Therefore, the reason why the poly-phosphate could effectively enhance the dispersion, whilst the mono-phosphate failed cannot be simply explained by the retard...

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“…, it was evident that Poly(MAST) copolymers with β‐CD pendants were effective cement dispersants, which was possibly owed to the more pronounced steric hindrance effect instigated by β‐CD and PEO side‐chains, in contrast to that of Poly(MAST)‐0 only from PEO side‐chains. For Poly(MAST) with β‐CD as pendant groups, Poly(MAST)‐24 with a higher content of β‐CD pendants was more effective than Poly(MAST)‐s24 with a higher number of PEO side‐chains, which signified that β‐CD pendants would improve the dispersion effectiveness of PCEs .…”

Section: Resultsmentioning

confidence: 99%

Effect of β‐cyclodextrin pendant on the dispersion robustness of polycarboxylate superplasticizer toward kaolin

Sun

Wei

2016

Polymer Composites

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Two types of polycarboxylate superplasticizers (PCEs) with b-cyclodextrin (b-CD) as pendant groups were synthesized by different methods to employ monovinyl b-CD monomer (MA-b-CD), and their dispersion robustness toward clay was evaluated by the dosage to achieve the specific spread value of the cement paste in the presence of 3 wt% kaolin. The interaction mechanism was investigated by X-ray diffraction analysis and adsorption measurement, and it was proposed that the sorption of PCEs on the surfaces of kaolin particles was weakened by b-CD pendants due to their pronounced steric hindrance effect. The results demonstrated that PCE with higher contents of b-CD pendants, which was synthesized via partially replacing poly(ethylene oxide) monomer by MA-b-CD, was more tolerant toward kaolin. POLYM. COMPOS.,

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Preparation and characterization of poly-carboxymethyl-β-cyclodextrin superplasticizer

Cited by 48 publications

References 24 publications

Preparation and Application of New Polycarboxylate Superplasticizers with Mild Retarding Performance Based on Monovinyl β-Cyclodextrin Monomer

Preparation and Application of New Polycarboxylate Superplasticizers with Mild Retarding Performance Based on Monovinyl β-Cyclodextrin Monomer

Effect of Sodium Hexametaphosphate and Trisodium Phosphate on Dispersion of Polycarboxylate Superplasticizer

Effect of β‐cyclodextrin pendant on the dispersion robustness of polycarboxylate superplasticizer toward kaolin

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