Synthesis and properties of different alkyl alcohol polyethers as the defoamers for concrete

Qiao, Min; Chen, Jian; Gao, Nanxiao; Shan, Guangcheng; Wu, Jingzhi; Ran, Qianping

doi:10.1016/j.colsurfa.2022.128998

Cited by 12 publications

(9 citation statements)

References 42 publications

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“…Figure 5 shows that the foam heights of all the samples increased gradually with the foaming time, and then decreased with the incubation time. The maximum foam heights decreased with the decrease in the amount of EO units, indicating that the defoamer containing less EO (higher hydrophobicity) had a higher defoaming ability in aqueous solutions [ 18 , 19 ]. It was also observed that compared with the defoamers linked with EO only, the defoamers linked with both EO and PO caused the foam heights to decay more quickly during the incubation time, and the defoamer linked with PO before EO (OPE2) caused the foam height to decay the most quickly.…”

Section: Resultsmentioning

confidence: 99%

“…Defoamer is a chemical admixture which has been widely used to inhibit and eliminate the harmful, large bubbles in fresh concrete [ 17 ]. By reducing the harmful bubbles and optimizing the pore structure of concretes, defoamers can improve the mechanical properties and service life of hardened concretes [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

“…In our previous study, we reported the polyether-type defoamers (amphiphilic surfactants) consisting of different hydrophobic alkyl chains (linear or branched, C14–25) and the same hydrophilic polyether chain (8 ethylene oxide units), which exhibited excellent defoaming performance [ 18 , 19 ]. The effect of hydrophobic alkyl chains on defoaming properties has been investigated, but the influence of a hydrophilic polyether chain (length and sequence) is still unknown.…”

Section: Introductionmentioning

confidence: 99%

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Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Qiao

Gao

et al. 2022

Materials

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In this study, a series of polyether-type defoamers for concrete which consist of the same alkyl chain (hydrophobic part) but different polyether chains (hydrophilic part) was prepared, and the structure–property relationship of the defoamers was investigated for the first time. Using oleyl alcohol (OA) as the starting agent (alkyl chain), the polyether defoamers with different polyether chains were prepared by changing the amount and sequence of ethylene oxide (EO) and propylene oxide (PO) units. The properties of different defoamers were tested in aqueous solutions, and fresh and hardened mortars; the structure–property relationship of the defoamers was thus studied. The results indicated that the defoaming capacity of the polyether defoamers decreased with an increased EO amount, and the defoamers linked with both EO and PO units (PO before EO) had a stronger defoaming capacity than those linked with EO only. This study is beneficial for the development and applications of novel synthetic polyether-type defoamers for concrete.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Qiao

Gao

et al. 2022

Materials

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“…Using the control method of “first elimination and then introduction”, the ratio of bubble area to the analysis area and the number of bubbles above 1 mm were greatly reduced, which played a significant role in improving the concrete surface appearance. The composite mixing of defoamer and PCE superplasticizer greatly affected the bubble spacing coefficient and bubble pore-size distribution of the concrete [ 68 , 69 ], among which the foaming and foam stabilization properties of the air-entraining agents played the most important role in affecting the concrete appearance [ 70 ]. A comprehensive comparison of Figure 21 reveals that the combined use of chemical admixtures can achieve a dynamic balance between improving and reducing workability, optimize the bubble structure, and enhance the bubble stability, thereby improving the concrete appearance quality [ 32 ].…”

Section: Influence Of the Structure Of Concrete Bubbles On The Appear...mentioning

confidence: 99%

Bubble Evolution under the Action of Polycarboxylate and Air-Entraining Agent and Its Effects on Concrete Properties—A Review

et al. 2022

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In order to improve the performance of concrete, it is of great significance to have a better understanding the mechanism and main influencing factors of concrete bubble evolution under the action of polycarboxylate and air-entraining agents. In the present review, with respect to the generation, growth, stability, and rupture of concrete bubbles under the action of polycarboxylate and air-entraining agents, this paper discusses the influence of bubble characteristics on concrete performance and studies bubble regulation by air-entraining agents and polycarboxylate (PCE) superplasticizer. The results show that the acid-to-ether ratio, sulfonic acid group, ester group, and the type of air entraining agent of the polycarboxylate acid structure have a significant impact on the bubbles. The bubble size, specific area, spacing factor, and bubble content have a significant impact on the rheological properties and related mechanical properties of fresh concrete and also affect the appearance quality of concrete. The problems with the experimental methods and theoretical models of concrete bubble research were analyzed, and future research ideas were put forward.

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“…There are mainly six types of commonly used defoamers, including natural products (such as mineral oils), polyethers, silicones, alkyl phosphates, polyetheramines, and polyether-modified silicones. − Among them, silicone-based emulsion-type defoamers have become one of the most popular categories in the field because of their high-branched structure and high interfacial activity, relatively better water solubility and compatibility with other admixtures, and excellent bubble-capturing ability for most foam systems. ,, Nevertheless, silicone compounds are generally more costly, and their high chemical stability leads to nondegradability; hence, they are increasingly unable to meet the growing environmental and safety requirements. − Therefore, the exploration of the nonsilicone active component as the core material of defoamers, whether from the economic, environmentally friendly, or intrinsically safe consideration, is an urgent need of the defoamer industry.…”

Section: Introductionmentioning

confidence: 99%

Multibranched Molecule Defoamers Based on Methyl Gallate for Highly Effective Defoaming and Antifoaming

Ju,

Hua,

Niu

et al. 2023

Langmuir

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Bubbles or foams appear in many industrial processes, bringing inconvenience; yet, efficient capture or removal of them is still challenging. In this study, we report the synthesis and properties of multibranched molecule defoamers based on methyl gallate derivatives (Mb-GDs), which adopt methyl gallate (M-G) as the parent structure, by incorporating alkyl groups from alkyl isocyanates (A-I) with different chain lengths (C12 and C18) to replace R−OH in the M-G structure and further by linking two Mb-GDs into one Gemini-type multibranched derivative (Gt-Mb-GD) by transesterification to construct a defoamer material with a larger spatial volume. The surface properties and interfacial activity of molecular defoamers in aqueous solutions were studied, and the structure−property relationships of the multibranched gallate molecule defoamers based on Mb-GDs and Gt-Mb-GDs were further investigated by comparing the defoaming and antifoaming performance in four typical surfactant foams and foaming solutions with two kinds of commercial defoamers. The foam experiments indicated that the defoamers with a longer branched chain length (C18) showed more effectiveness in defoaming and antifoaming for four surfactant foams or foaming solutions, even at very low dosages, which were far stronger than the commercial high-carbon alcohol defoamer with a linear structure and comparable to branched silicone-based emulsion-type defoamers. Compared with Mb-GD defoamers, Gt-Mb-GD defoamers with a larger branched structure showed a higher defoaming performance. The study found the great potential of materials with multibranched structures for practical applications as the core components of high-performance defoamers.

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Synthesis and properties of different alkyl alcohol polyethers as the defoamers for concrete

Cited by 12 publications

References 42 publications

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Bubble Evolution under the Action of Polycarboxylate and Air-Entraining Agent and Its Effects on Concrete Properties—A Review

Multibranched Molecule Defoamers Based on Methyl Gallate for Highly Effective Defoaming and Antifoaming

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