A study of supermolecular polarization of comb-like polycarboxylate admixtures synthesized with polyoxyethylene macromolecules

Duan, Gengli; Huang, Guohong; Li, Aimei; Zhu, Yeran; Gong, Ying

doi:10.1016/j.molliq.2012.07.013

Cited by 14 publications

(12 citation statements)

References 18 publications

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“…The optimum molar ratio of the monomers n/m in PCE was 3.6. Vinyl acetate [12] Methyl acrylate [26] Methacrylamide [12] 2-Hydroxyethyl methacrylate Plank et al [48] modified the poly(ethylene oxide), the side chain of the polycarboxylates, changing its length and kind of terminal group. The authors studied the polycarboxylate superplasticizers with the side chains composed of 17, 24 or 45 repeating units of ethylene oxide, terminated with the hydroxyl (-OH) or methoxy (-OCH 3 ) group [Formula (I)].…”

Section: Influence Of the Chemical Structure Of Polycarboxylates On Tmentioning

confidence: 99%

“…In classical cement--based media at room temperature, PCEs behave generally as polymers in good solvent, except in case of very high sulfate concentration. Duan et al [12] studied the molecular polarization of polycarboxylate by measurement of electrical conductivity in deionized water solution. It was found that the PCE significantly increased the conductivity of the solution with maximum values reached at PCE concentrations between 20 and 25 wt %.…”

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confidence: 99%

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Polymeric superplasticizers based on polycarboxylates for ready-mixed concrete: current state of the art

2016

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Chemical admixtures are one of the basic components of the contemporary concrete. The most important admixtures are superplasticizers, i.e. the modifiers which allow for high-range reducing of the water content in the concrete mix. The most effective superplasticizers are based on polycarboxylates and their derivatives. The state of the art in the range of polycarboxylate admixtures for concrete is presented in the paper. The methods of synthesis and modification of carboxylic polymers are characterized and the mechanism of action of polycarboxylate superplasticizers is described. The influence of the chemical structure of polycarboxylates on the consistence of the concrete mix, as well as the prognosis of the superplasticizers development is also presented.

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Section: Influence Of the Chemical Structure Of Polycarboxylates On Tmentioning

confidence: 99%

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confidence: 99%

Polymeric superplasticizers based on polycarboxylates for ready-mixed concrete: current state of the art

2016

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“…From a chemistry viewpoint, there are several factors that feature the impact of superplasticizers in concrete systems . The main structural factors responsible for superplasticizer efficacy are the length of the polymer backbone, the length of side chain, and the number and density of the side chains . Yamada et al .…”

Section: Introductionmentioning

confidence: 99%

High‐performance carboxylate superplasticizers for concretes: Interplay between the polymerization temperature and properties

Tajbakhshian

Saeb

Jafari

et al. 2017

J of Applied Polymer Sci

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Polycarboxylate superplasticizers based on acrylic acid (AA) and maleic anhydride (MAn) were synthesized via free-radical copolymerization with an ethylene glycol monomer and characterized. The copolymerization temperature (ranging from 50 to 90 8C) appeared to be the key operating factor governing the chemical structure of the superplasticizers. The chemical structures of the products were analyzed by gel permeation chromatography, whereas an optimized sample was further analyzed by Fourier transform infrared spectroscopy and 1 H-NMR. Superplasticizers of the AA and MAn classes were then incorporated into concrete, and their performances were measured by slump and slump loss tests, where a large dependency of the microstructure on the synthesis temperature was recognized. The optimum temperatures were found to be 50 and 80 8C for the AA and MAn modifiers, respectively. At their own optimum temperatures, the AA and MAn superplasticizer revealed slump losses from 23 to 4 cm and 15 to 5 cm, respectively, after 45 min. The chemical structures of the plasticizers were patterned illustratively to speculate the performance of each superplasticizer according to changes that took place in the backbone length and side-chain density.

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“…At low water contents, superplasticizers, which are polymers that can facilitate the dispersion of cement particles, are utilized to provide necessary workability. Superplasticizers adsorb onto the surface of the cement particles through their charged backbone and provide electrostatic repulsion 4 5 . They release the entrapped water from flocculated structures and modify the viscosity of cement mixtures 6 7 .…”

mentioning

confidence: 99%

“…Latest generations, poly(carboxylate ether)-based superplasticizers, (PCEs), have acrylate groups in the backbone and also contain side chains (i.e., poly(ethylene oxide)) that protrude from the cement surface into the pore solution to produce steric hindrance effect 8 9 . These grafted polymers exhibit superior dispersing ability compared to other types of superplasticizers (e.g., melamine and naphthalene based polycondensates) and are efficient in the preparation of high performance concrete 5 10 11 .…”

mentioning

confidence: 99%

Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement

Akhlaghi

Menceloǵlu

Akbulut

2017

Sci Rep

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Calcium aluminate cement (CAC) suffers from loss of workability in less than an hour (~15 minutes) after first touch of water. Current superplasticizers that are utilized to modify the viscosity of cement admixtures are designed to target ordinary Portland cement (OPC). The high affinity between these superplasticizers and cement particles were found to be detrimental in CAC systems. Utilization of a monomer that, instead, facilitates gradual adsorption of a superplasticizer provides workability retention. For the first time in literature, we report a superplasticizer that caters to the properties of CAC such as high rate of surface development and surface charge. While neat CAC was almost unworkable after 1 hour, with the addition of only 0.4% of the optimized superplasticizer, 90% fluidity retention was achieved.

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A study of supermolecular polarization of comb-like polycarboxylate admixtures synthesized with polyoxyethylene macromolecules

Cited by 14 publications

References 18 publications

Polymeric superplasticizers based on polycarboxylates for ready-mixed concrete: current state of the art

Polymeric superplasticizers based on polycarboxylates for ready-mixed concrete: current state of the art

High‐performance carboxylate superplasticizers for concretes: Interplay between the polymerization temperature and properties

Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement

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