Synthesis of lignin-grafted polycarboxylate superplasticizer and the dispersion performance in the cement paste

Zhong, Dingming; Liu, Qiandi; Zheng, Dafeng

doi:10.1016/j.colsurfa.2022.128689

Cited by 16 publications

(6 citation statements)

References 26 publications

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“…Sodium aluminate (NaAlO 2 ) was selected as an effective accelerator, which was used to facilitate concrete setting and strength gain speed [21]. Lignin water-reducing agent was used to obtain high fluidity concrete with a low water-cement ratio, and favorable characteristics such as good water retention and slump retention [22,23]. Bentonite, with montmorillonite as the main mineral component, as a representative nonmetallic clay material, has been proven to be efficient in the removal of heavy metal ions.…”

Section: Additivesmentioning

confidence: 99%

Research and Application of High-Pressure Rotary Jet Method in the Seepage Treatment of Heavy Metal Tailing Ponds of Southwest China

et al. 2023

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The developed karst caves may become the seepage channels of heavy metal to the soil and underground water in Southwest China. Therefore, it is necessary to apply effective seepage treatments to the base of heavy metal tailing reservoirs. This paper addressed the high-pressure rotary jet technology and slurry systems used in the seepage treatment of the deep tailing sand of the Shenxiandong tailing pond located in Southwest China. In this study, the factors of fluidity, initial and final setting times, compressive strength, and permeability coefficient of the slurry were conducted. The mechanism analysis was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and inductively coupled plasma-mass spectrometry (ICP-MS). Three different types of slurry systems were proposed, and the permeability coefficients of the solidification body following 28 days of curing were less than 1 × 10−7 cm/s. The concentrations of Pb and Zn in the slurry system containing bentonite were reduced by 26.2% and 45.7%, respectively. In the presence of slaked lime and fly ash, the concentrations of Pb and Zn could be reduced by 26.8% and 30%, respectively. A total of 2142 high-pressure rotary jet piles were completed by the high-pressure rotary jet method in the field trial. The diffusion radius of these piles was over 1 m. Following 28 days of curing, the solidification body’s compressive strength was 7.45 MPa and the permeability coefficient was 6.27 × 10−8 cm/s. Both the laboratory and on-site trials showed that this method produced a good pollution barrier effect, which could prevent the diffusion of heavy metal into the adjacent underground water through the karst caves. It is also an effective way of engineering technology concerning heavy metal pollution control that occurs in tailing ponds.

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Section: Additivesmentioning

confidence: 99%

Research and Application of High-Pressure Rotary Jet Method in the Seepage Treatment of Heavy Metal Tailing Ponds of Southwest China

et al. 2023

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“…As a type of biomass resource that is renewable and abundant on Earth, lignin-based materials have potential for sustainable application. Lignin-grafted polymers are superplasticizers with varied structures [150][151][152][153][154][155]. Side chains can be grafted onto the lignin frame by phenol-group-initiated radical polymerization.…”

Section: Topological Structure and Polymer Molecular Framementioning

confidence: 99%

Advances in Organic Rheology-Modifiers (Chemical Admixtures) and Their Effects on the Rheological Properties of Cement-Based Materials

et al. 2022

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Organic rheology modifiers, especially superplasticizers and viscosity-modifying admixtures (VMAs), have become key components for the workability optimization of modern concrete. The development of these admixtures is crucial to the further performance improvement of modern concrete under different casting and service conditions. Many of the former reviews have summarized research advances in respect of these admixtures from chemical and material perspectives, focusing on the effects of structure and the performance. In this paper, from a rheological perspective, an overview is provided of the microscale behavior of polycarboxylate (PCE) superplasticizers and VMAs (e.g., adsorption, conformation, and bridging) in terms of the evolution of the microstructure of the paste, the effect of chemical structure on the yield stress, the apparent viscosity and thixotropy of cement-based materials, and the structure design of these admixtures. Most importantly, in addition to a general discussion with assumptions (monolayer adsorption of a “flat” conformation, with each molecule on a single particle; statistical polymer composition), special conditions (e.g., preferential adsorption, depletion effects, hydration modification effects, and the polydispersity of the polymer composition) are discussed. Newly developed admixtures, realized through regulation of the microscale behavior, and by the modification of adsorption, topological structure, and molecular frame, are introduced.

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“…Meanwhile, during the synthesis process of PCEs, some polyether monomers need higher synthesis temperature (above 60 °C) and long reaction time (above 1 h) in the synthesis of PCEs. 9 However, the sixcarbon polyether macromonomer (VPEG) is a promising candidate to reduce the reaction temperature, shorten the reaction time, and save cost because of the high reaction activity.…”

Section: Introductionmentioning

confidence: 99%

“…If the acid-to-ether ratio of PCE is adjusted, the mechanical properties of cement stone can be improved, thereby prolonging the service life of cement, which is conducive to sustainable development. Meanwhile, during the synthesis process of PCEs, some polyether monomers need higher synthesis temperature (above 60 °C) and long reaction time (above 1 h) in the synthesis of PCEs . However, the six-carbon polyether macromonomer (VPEG) is a promising candidate to reduce the reaction temperature, shorten the reaction time, and save cost because of the high reaction activity.…”

Section: Introductionmentioning

confidence: 99%

Preparation of a Polycarboxylate Superplasticizer with Different Monomer Regulations and Its Effect on Fluidity, Rheology, and Strength of Cement

Chang,

Hu,

Liu

et al. 2024

Langmuir

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Polycarboxylate superplasticizers (PCEs) are indispensable functional ingredients in modern construction, and their usage is extensive. Herein, a polyether macromonomer (VPEG) with high reactivity was used to prepare VAPCEs with different interfacial adsorption properties (acid−ether ratio) at low temperatures and reacted in 30 min. The effects of various VAPCEs on the fluidity, rheology, and strength of cement were investigated with a w/c (water/ cement) ratio of 0.35. Results showed that VAPCE-3 (acid−ether ratio is 3) exhibited the best dispersion, and the fluidity of cement slurry with VAPCE-3 (280 mm) is 278.38% higher than that of the control sample (74 mm). The reason is summarized as VAPCE-3 having good adsorption performance on the surface of cement particles and having a large steric hindrance between particles. The compressive strength of cement with VAPCE-3 was enhanced by 8.29% compared with pure cement in 3 days of curing age due to its densification on microstructure and lowest R orientation index of calcium hydroxide. With the amount of acrylic acid in VAPCE increasing, the flexural strength enhanced because a more cross-linking network was formed with Ca 2+ in cement with the increase of COO − content in VAPCEs.

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Synthesis of lignin-grafted polycarboxylate superplasticizer and the dispersion performance in the cement paste

Cited by 16 publications

References 26 publications

Research and Application of High-Pressure Rotary Jet Method in the Seepage Treatment of Heavy Metal Tailing Ponds of Southwest China

Research and Application of High-Pressure Rotary Jet Method in the Seepage Treatment of Heavy Metal Tailing Ponds of Southwest China

Advances in Organic Rheology-Modifiers (Chemical Admixtures) and Their Effects on the Rheological Properties of Cement-Based Materials

Preparation of a Polycarboxylate Superplasticizer with Different Monomer Regulations and Its Effect on Fluidity, Rheology, and Strength of Cement

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