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

Abstract

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.,

Performance of Polymer Cementitious Coatings for High-Voltage Electrical Infrastructure

“…The SA emulsion (XQS-200) used in these mixes had a solid particle content of 48-52%, monomer content of 0.1-0.5%, a pH of 8-9 and a viscosity between 1000-2000 (mPass). Additionally, a polycarboxylate superplasticiser and an aqueous defoamer were employed to improve the workability of the mixture [28,29].…”

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

“…2 Due to its special structure and extraordinary properties, β-CD has been studied in a wide variety of fields, [3][4][5] such as acting as water-reducing agents directly 6 or as a powerful group to modify polycarboxylate superplasticizer (PCE) for improving the dispersion, retarding, and clay-tolerance properties. [7][8][9][10][11] For synthesizing PCE containing the β-CD group, monovinyl β-CD monomer is the first and key step, however, the monovinyl β-CD monomer's preparation methods are very few due to the fact that β-CD has three types of hydroxyl groups (at position 2, 3, or 6) for the reaction. 12,13 Fortunately, in the alkaline environment, hydroxyl groups at position 6 are the most accessible to react with electrophilic reagents.…”

“…Li et al and Xu et al successfully achieved the monovinyl β-CD monomer's preparation using the easy leaving electrophilic group p-toluenesulfonyl. [8][9][10] Recently, Meng et al prepared the monovinyl β-CD monomer through the reaction of β-CD with m-nitrophenyl acrylate. 11,15 In their researches, the monovinyl β-CD monomer and PEO were used as two different monomers with a "parallel relationship" during the preparation of PCE.…”

“…In this truncated cone, the glucopyranose units' primary and secondary hydroxyl groups remain on the narrow and wide faces, respectively 2 . Due to its special structure and extraordinary properties, β‐CD has been studied in a wide variety of fields, 3–5 such as acting as water‐reducing agents directly 6 or as a powerful group to modify polycarboxylate superplasticizer (PCE) for improving the dispersion, retarding, and clay‐tolerance properties 7–11 …”

“…This feature can be utilized to prepare a monovinyl β‐CD monomer. Li et al and Xu et al successfully achieved the monovinyl β‐CD monomer's preparation using the easy leaving electrophilic group p‐toluenesulfonyl 8–10 . Recently, Meng et al prepared the monovinyl β‐CD monomer through the reaction of β‐CD with m‐nitrophenyl acrylate 11,15 .…”