Syntheses of polycarboxylate superplasticizers: Microwave induction versus conventional thermal induction

Zhang, Liran; Du, Weidong; Wang, Dongmin; Fang, Kuizhen; Yu, Jie; Sheng, Bo

doi:10.1016/j.compositesb.2020.108560

Cited by 16 publications

(18 citation statements)

References 46 publications

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“…Then, the actual monomer molar ratios of the macromonomer to AA in PCEs are quantitatively analyzed via 1 H NMR spectroscopy. The –CH and –CH 3 of the main chain in PCEs have different chemical shifts in 1 H NMR, and the actual monomer molar ratio can be obtained by comparing their peak areas. , Table shows that P1 and P2 represent characteristic hydrogen signals of macromonomer and AA in copolymer repeating units, respectively. These signals are used to quantify the actual molar ratio of macromonomer to AA.…”

Section: Resultsmentioning

confidence: 99%

“…The structures of HPEG, mYPEG, and YPEG were characterized by 1 H NMR and 13 C NMR, and the actual monomer molar ratios of AA to macromonomer in the PCE copolymers were quantitatively analyzed by 1 H NMR. 24,25 PCEs were dissolved in deuterated DMSO at a concentration of 0.1 g/mL and then tested by an AVANCE Digital 600 MHz Nuclear Magnetic Resonance Spectrometer (Brook Co., Germany). The peak positions of the hydrogen spectrum and carbon spectrum of DMSO are 2.50 and 39.61 ppm, respectively.…”

Section: Nuclear Magneticmentioning

confidence: 99%

“…Molar Ratios of Macromonomer to Acrylic Acid in the Purified PCE Co-polymers from the 1 H NMR Analysis25 …”

mentioning

confidence: 99%

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Reconfiguring Molecular Conformation from Comb-Type to Y-Type for Improving Dispersion Performance of Polycarboxylate Superplasticizers

Zhou,

Duan,

et al. 2024

Macromolecules

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Steric repulsive force is the main dispersion force between cement particles. In order to improve the dispersibility of polycarboxylate superplasticizers (PCEs), we designed and synthesized a new Y-type macromonomer (YPEG) with a molecular weight of M w = 4100 Da. A long side chain-branched polycarboxylate superplasticizer (YPCE) was successfully synthesized by employing YPEG. Several common comb PCEs having the same side chain density but different lengths, such as PCE2400 and PCE4000, are employed to compare with YPCE for evaluating the dispersion performance. The results show that YPCE has a more excellent dispersion performance than the common PCEs under different water−cement ratios. Additionally, YPCE shows stronger water reduction for concrete. Furthermore, a dynamic light scattering study elucidates that YPCE can increase the adsorbed layer thickness from 5.6 to 7.9 nm, thus forming stronger steric hindrance. Simulations using molecular dynamics are conducted to investigate the influence of the conformational transformation of PCEs from comb-type to Y-type on the adsorption configuration and radius of gyration (R g ) of PCEs on calcium silicate hydrate surface. It is observed that the side chain of YPCE remains in an extended state, and R g fluctuates little during the fitting process. This study provides a new strategy to enhance the steric hindrance of PCEs.

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Section: Resultsmentioning

confidence: 99%

Section: Nuclear Magneticmentioning

confidence: 99%

See 1 more Smart Citation

Reconfiguring Molecular Conformation from Comb-Type to Y-Type for Improving Dispersion Performance of Polycarboxylate Superplasticizers

Zhou,

Duan,

et al. 2024

Macromolecules

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“…However, the above extraction or dissolution methods have some disadvantages, such as high price, harsh extraction conditions, low extraction rate, or the use of non-environmentally friendly reagents, which restricts wool recycling. In addition, the current methods are mostly traditional heating methods, which are in the form of heat conduction and convection, resulting in a large amount of heat loss (Zhang et al, 2021). Therefore, researchers are focusing on finding a simple, low-cost, green method to extract and dissolve wool keratin.…”

Section: Introductionmentioning

confidence: 99%

Green and Highly Efficient Wool Keratin Extraction by Microwave Induction Method

Zhang

et al. 2022

Front. Mater.

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Keratin is a plentiful and renewable fibrous protein resource found in nature, but a great deal of keratin-containing waste causes environmental problems, especially wool waste, which accounts for the majority. A green and efficient extraction method of keratin based on microwave induction method was studied. Compared with traditional thermal induction, the extraction time was shortened by half, and the dissolution rate of the wool was improved. The effects of the above two methods on the size, structure, crystallinity, and thermal stability of wool keratin were studied by a series of analysis methods [e.g., attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), Raman spectroscopy, X-ray diffraction spectroscopy (XRD), dynamic light scattering (DLS), thermogravimetric analysis (TG), and so on]. The results showed that under microwave irradiation, the disulfide bonds were destroyed greatly, and the secondary structure changed significantly, which was beneficial to obtain wool keratin with low crystallinity and small particle size.

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“…The main mechanism of the dispersion is the π–π-stacking effect between their nanocrystalline graphite and the phenyl groups of dispersants. In addition, on the basis of the dispersion mechanism of polycarboxylate ether (PCE) copolymer with a comb-shaped structure in cement paste (namely, the charged main chain provides electrostatic repulsion and the side chain provides steric hindrance), − some scholars attempt to use PCE to disperse GO layers, but the stability of GO is not satisfied . On the basis of the π–π-stacking effect of phenyl on carbon-based materials, it is valuable to attempt to synthesize and discuss the dispersion effect of styrene–PCE copolymer on GO layers.…”

Section: Introductionmentioning

confidence: 99%

Stability of Phenyl Copolymer–Graphene Oxide Composites in High-Alkali and/or -Calcium Environments: Implications for Strengthening and Toughening Cement-Based Materials

Wang

Zhang

Wang

et al. 2022

ACS Appl. Nano Mater.

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On the basis of their size effect and structural characteristics, carbon nanomaterials have great application potential in building materials, especially for strengthening and toughening cement-based materials. However, because of the poor dispersant of graphene oxide (GO) in cement-based materials with high-alkalinity and high-calcium content, its application in cement concrete is facing great challenges. Here, a method of self-assembling GO by phenyl polymer to achieve effective dispersion is reported. The good dispersion stability is due to hybridization between the phenyl group of the polymer and GO through noncovalent interactions, so the polymer can be anchored to the surface of the GO sheet and dispersed by steric hindrance of the side chain of poly(ethylene oxide) (PEO). The results show that when the length of the PEO side chain is constant, the phenyl content in the copolymer may not only affect the π−πstacking interaction (from offset face-to-face to edge-to-face) but also significantly affect the dispersion stability of the system. When the molar ratio of phenyl to the PEO side chain is about 2, it shows good dispersibility (i.e., the size of the self-assembled composite is the smallest). This provides reference and enlightenment for regulation of the dispersion stability of GO under severe environmental conditions.

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Syntheses of polycarboxylate superplasticizers: Microwave induction versus conventional thermal induction

Cited by 16 publications

References 46 publications

Reconfiguring Molecular Conformation from Comb-Type to Y-Type for Improving Dispersion Performance of Polycarboxylate Superplasticizers

Reconfiguring Molecular Conformation from Comb-Type to Y-Type for Improving Dispersion Performance of Polycarboxylate Superplasticizers

Green and Highly Efficient Wool Keratin Extraction by Microwave Induction Method

Stability of Phenyl Copolymer–Graphene Oxide Composites in High-Alkali and/or -Calcium Environments: Implications for Strengthening and Toughening Cement-Based Materials

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