UHPC (Ultra High Performance Concrete) system adaptive ultrahigh dispersing agent for esterifying and grafting crown ether side chain

Abstract

According to the scheme, glycerin, crown ether compounds, unsaturated carboxylic acid monomers and the like are adopted as main reaction raw materials, glycerin is adopted as a framework, hydroxyl polyethylene glycol bromide is grafted through a nucleophilic substitution reaction, a substitution product and the crown ether compounds are subjected to an esterification reaction, and the UHPC system ultrahigh dispersing agent with the esterification grafted crown ether side chains is obtained. And carrying out free radical copolymerization reaction on the esterification product, unsaturated carboxylic acid, unsaturated phosphoric acid and a chain transfer agent in a redox system to prepare the crown ether modified comb-shaped superhigh dispersing agent. The preparation process is simple and easy to control, energy-saving, efficient, environment-friendly and pollution-free, the comb-shaped crown ether dispersing agent is prepared through a method of grafting hydroxyl polyethylene glycol bromide through nucleophilic substitution, the hydrophilicity and steric hindrance effects of PEG chain segments can be fully played, the crown ether and a main chain can form a synergistic effect by means of the ion chelation function of crown ether, and therefore the dispersion effect of the comb-shaped crown ether dispersing agent is improved. The water-reducing and slump-retaining properties of the dispersing agent are remarkably improved, and the scheme has good application value and wide market prospect.

Description

Technical Field

[0001] This invention relates to the field of UHPC soil-use water-reducing ultra-high dispersant technology, and in particular to an esterified grafted crown ether side chain adapted UHPC system ultra-high dispersant which is formed by replacing grafted hydroxyl polyethylene glycol bromide with glycerol as the backbone, esterifying it with crown ether compounds, and then copolymerizing it with unsaturated carboxylic acids and unsaturated phosphoric acid. Background Technology

[0002] Ultra-high strength concrete (UHPC), as a building material possessing ultra-high strength, excellent durability, and good workability, plays an irreplaceable role in harsh environmental engineering projects such as marine engineering, bridges, and projects in frigid regions. Its performance depends heavily on the compatibility and stability of ultra-high dispersants. The core function of ultra-high dispersants is to improve the flowability of cementitious materials in the UHPC system while ensuring the mechanical properties and durability of the hardened concrete. Therefore, developing ultra-high dispersants for UHPC with excellent comprehensive performance has become a hot topic in concrete admixture research and development.

[0003] Traditional dispersants, when incorporated into UHPC (Ultra-High-Performance Polymer), require increased dosage to achieve the desired casting performance. However, increasing the dosage not only raises manufacturing costs but also significantly reduces the slurry's encapsulation properties, severely compromising the mechanical and durability properties of UHPC. Furthermore, UHPC contains a large amount of mineral admixtures such as silica fume, fly ash, and slag powder, which traditional water-reducing agents readily adsorb onto the surface of these admixture particles, greatly reducing their dispersibility. Moreover, the side chains of traditional dispersants are susceptible to interference from metal ions in the complex cementitious system of UHPC, leading to decreased dispersion stability. Therefore, developing novel ultra-high dispersants suitable for UHPC to reduce the viscosity of UHPC mixtures and improve their flow properties has significant theoretical research value and engineering practical implications.

[0004] Optimizing dispersant performance at the molecular structure design level is the most common approach. Introducing polar, multifunctional groups, such as carboxyl, sulfonic acid, and siloxane groups, can enhance their binding competitiveness with cement particle surfaces, reduce preferential adsorption of mineral admixtures, increase the number of effectively dispersed molecules, and strengthen the dispersion stability of cementitious particles. Phosphate groups exhibit irreplaceable advantages in the molecular structure design of ultra-high dispersants. From a binding capacity perspective, phosphate groups have three dissociable protons, forming stable phosphate anions in alkaline environments. Their interaction with calcium ions is much stronger than that of carboxylates, maintaining extremely strong adsorption stability. Furthermore, phosphate groups exhibit a synergistic adsorption effect with the silanol groups on the silica fume surface, binding cement particles through polar interactions and forming Si-OP chemical bonds with the silica fume surface, thus dispersing silica fume. Therefore, introducing phosphate groups into the molecular structure design can enhance binding stability and compensate for the performance deficiencies of traditional polar groups.

[0005] Crown ethers, as a class of functional compounds with specific cyclic cavity structures, can specifically chelate Ca²⁺ in cement systems that affect dispersion stability. + Na + Metal ions are expected to help improve the dispersion efficiency and environmental adaptability of dispersants, becoming key additives for improving dispersant performance. However, the ether oxygen atoms and hydroxyl groups within crown ether molecules easily form intramolecular hydrogen bonds, leading to the masking of their surface hydrophilic groups and increased hydrophobicity. PEG, being a hydrophilic linear molecule, exhibits poor compatibility with PEG, making it impossible to form a uniform and stable mixture, severely limiting its practical application in UHPC dispersants. While existing technologies employ crown ether grafting of PEG side chains to improve compatibility, conventional grafting processes often rely on high-temperature etherification reactions, requiring temperatures above 80°C and the assistance of dehydrating agents. This not only results in high energy consumption but also easily leads to PEG chain segment breakage and destruction of the crown ether cyclic structure, accompanied by numerous side reactions, making it difficult to achieve efficient and stable grafting of crown ethers and PEG. Therefore, there is an urgent need to develop novel side chains with crown ether structures. It is necessary to innovatively synthesize UHPC ultra-high dispersants containing carboxyl and phosphate groups based on molecular structure design concepts to improve the flowability of UHPC and ensure its strength development. There are no relevant reports on this work at home and abroad. Summary of the Invention

[0006] In view of this, the purpose of this invention is to propose an esterified grafted crown ether side chain-compatible ultra-high dispersant for UHPC systems and its preparation method. In this scheme, glycerol is used as the backbone, and hydroxyl polyethylene glycol bromide is grafted through nucleophilic substitution reaction. The substitution product undergoes esterification reaction with crown ether compounds. The esterification product is then subjected to free radical copolymerization reaction with unsaturated carboxylic acid, unsaturated phosphoric acid, and chain transfer agent in a redox system to obtain a crown ether-modified comb-like ultra-high dispersant.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by this invention is as follows: An esterified grafted crown ether side chain-compatible ultra-high dispersant for UHPC systems, the molecular formula of which is shown in Formula 1:

[0008] Formula 1.

[0009] Based on the above, this solution also proposes a method for preparing an ultra-high dispersant adapted to the UHPC system by esterification grafting crown ether side chains, which includes the following steps: (1) Substitution reaction: Glycerol and anhydrous dichloromethane were added to a dry three-necked flask and stirred to dissolve. The temperature was controlled at 0-5°C in an ice bath. An acid-binding agent was added and stirred for 10-15 min. Methacrylamide chloride was slowly added dropwise for 1-2 h. After the addition was complete, the temperature was raised to 30-45°C and the reaction was stirred at a constant temperature for 1-1.5 h. After the reaction was completed, deionized water was added and washed 3 times. The organic phase was separated, dissolved under reduced pressure, and dried under vacuum for 1-2 h to obtain glycerol with double bonds. (2) Substitution reaction: The glycerol with double bonds obtained in step (1), hydroxyl polyethylene glycol bromide, and anhydrous N,N-dimethylformamide are added to a three-necked flask, stirred evenly, and a catalyst and polymerization inhibitor are added. The temperature is raised to 30~40℃ and stirred at a constant temperature for 2.5~3h to allow it to undergo a nucleophilic substitution reaction. The hydroxyl group of the glycerol with double bonds acts as a nucleophile to attack the brominated end of the hydroxyl polyethylene glycol bromide, replacing the bromine atom and forming an ether bond to obtain a comb-like intermediate with PEG side chains. (3) Esterification reaction: The comb-shaped intermediate obtained in step (2) and the crown ether compound were added to a three-necked flask, stirred and dissolved, a catalyst was added, the temperature was controlled at 35~50℃, and the reaction was stirred at a constant temperature for 2~2.5h. After the reaction was completed, deionized water was added and washed 3 times. The organic phase was separated and desolvated under reduced pressure to obtain the comb-shaped side chain monomer with crown ether. (4) Copolymerization: Deionized water was added to a three-necked flask and the temperature was controlled at 20-30°C. Then, the oxidant and the comb-shaped side-chain monomer obtained in step (3) were added and stirred evenly. An aqueous solution of reducing agent and chain transfer agent was added dropwise to one end of the flask, and an aqueous solution of unsaturated carboxylic acid and unsaturated phosphoric acid was added dropwise to the other end for 2-3 hours. After the addition was completed, the reaction was continued at a constant temperature for 3-3.5 hours. After the reaction was completed, the pH was adjusted to 7-8 with sodium hydroxide aqueous solution to obtain the comb-shaped crown ether dispersant.

[0010] As a preferred embodiment, the acid-binding agent in step (1) of this scheme is preferably triethylamine, and its dosage is 0.5% to 1.5% of the mass of glycerol; The molar ratio of methacryloyl chloride to glycerol in step (1) is 0.5~1:1; The amount of anhydrous dichloromethane used in step (1) is 2 to 3 times the total mass of glycerol, acid binder and methacryloyl chloride.

[0011] As a preferred embodiment, the hydroxyl polyethylene glycol bromide in step (2) of this scheme is preferably HO-PEG-Br with a molecular weight of 2000; the molar ratio of its amount to the glycerol with double bonds is 2~3:1. The amount of anhydrous N,N-dimethylformamide used in step (2) is 1.5 to 2 times the total mass of the double-bonded glycerol, hydroxyl polyethylene glycol bromide, catalyst and polymerization inhibitor; The catalyst mentioned in step (2) is one of anhydrous potassium carbonate, anhydrous sodium carbonate, or triethylamine, and its amount is 0.5% to 1.5% of the mass of the glycerol with double bonds; The polymerization inhibitor mentioned in step (2) is 2,6-di-tert-butyl-p-cresol or hydroquinone, and its amount is 1% to 2% of the mass of the glycerol with double bonds.

[0012] As a preferred embodiment, preferably, the crown ether compound in step (3) of this scheme is one of 3-carboxy-15-crown-5, 4-carboxybenzo-15-crown-5 or 15-crown-5-acetic acid, and the molar ratio of its amount to the comb-like intermediate is 2~3:1; The catalyst in step (3) is N-hydroxysuccinimide or 1-ethyl-3-dimethylaminopropylcarbodiimide, and its amount is 0.6% to 1.5% of the mass of the comb-shaped intermediate.

[0013] As a preferred embodiment, the oxidant in step (4) of this scheme is preferably hydrogen peroxide, and its amount is 0.6% to 1.5% of the mass of the comb-shaped side-chain monomer with crown ether; The reducing agent in step (4) is ascorbic acid, and its amount is 1% to 2% of the mass of the comb-shaped side-chain monomer with crown ether; The chain transfer agent in step (4) is mercaptoacetic acid or mercaptopropionic acid, and its amount is 1% to 2% of the mass of the comb-shaped side chain monomer with crown ether; The unsaturated phosphoric acid mentioned in step (4) is 2-hydroxyethyl methacrylate phosphate, and the molar ratio of its amount to the comb-shaped side chain monomer with crown ether is 2~4:1; The unsaturated carboxylic acid mentioned in step (4) is acrylic acid, and the molar ratio of its amount to the comb-shaped side chain monomer with crown ether is 2~6:1.

[0014] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. Based on the principles of molecular structure design, this invention uses glycerol as a backbone and grafts hydroxyl-containing polyethylene glycol bromides through a nucleophilic substitution reaction. The substitution product undergoes an esterification reaction with crown ether compounds. The esterified product is then copolymerized with unsaturated carboxylic acids, unsaturated phosphoric acids, and a chain transfer agent in a redox system via free radical polymerization to obtain a crown ether-modified comb-like ultra-high dispersant. This dispersant contains multiple adsorption groups, increasing the polymer's adsorption capacity. When applied to UHPC systems, it exhibits excellent water-reducing effects while ensuring the development of UHPC strength. This represents an innovation and breakthrough in the molecular structure design and preparation of ultra-high dispersants, providing technical guidance for future in-depth research and promotion of ultra-high dispersants.

[0015] 2. The method of this invention innovatively uses glycerol as the backbone to replace the grafted hydroxyl polyethylene glycol bromide and then reacts it with crown ether compounds to synthesize a comb-shaped side-chain monomer with crown ether. This structure is non-ionic and free from charge repulsion interference. It generates stable steric hindrance through the linear structure of the PEG chain segment and achieves metal ion chelation through the cyclic cavity of the crown ether, thereby improving the stability and water-reducing performance of the ultra-high dispersant. It has significant performance advantages and application prospects.

[0016] 3. This synthesis process is safe and environmentally friendly, uses readily available raw materials, has a simple process flow, low production costs, and is clean and pollution-free. All reaction processes do not require high temperatures, which helps reduce side reactions, maintains the stability of the reaction system, and achieves a high product yield. Furthermore, the crown ether compounds and hydroxylated polyethylene glycol bromides used as raw materials have a wide applicable molecular weight range, which is beneficial for obtaining products with different molecular structure parameters, thereby promoting the widespread adoption and application of this type of polycarboxylate superplasticizer.

[0017] 4. The nucleophilic substitution, esterification, and free radical copolymerization reaction steps used in this invention are all common operating processes in the field of organic synthesis, requiring no special reaction procedures or expensive auxiliaries. The synthetic route is simple and controllable, conforming to the principles of green design synthesis. Furthermore, the synthesis process has no special requirements for production equipment and can be adapted to existing dispersant synthesis processes, eliminating the need for additional dedicated equipment and facilitating continuous industrial production. The synthesized product retains the steric hindrance, dispersing functional groups, and ion-chelating functional groups of the PEG chain segments, exhibiting excellent water-reducing and slump-retention properties. It demonstrates strong molecular designability, controllable molecular weight, and uniform degree of polymerization, making it a promising novel nonionic comb-shaped crown ether dispersant. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To facilitate the explanation of the compatibility of this solution with the esterified grafted crown ether side chain and the ultra-high dispersant in the UHPC system, the following comparison is made with several examples and comparative examples.

[0020] In the comparative test of the schemes, the grade of silicate cement used in each case was P·O52.5. The UHPC mix proportion components provided by the scheme test included, by weight, 36 parts silicate cement; 4 parts silica fume; 5 parts metakaolin; 11 parts 70-110 mesh quartz sand; 15 parts 26-40 mesh quartz sand; 20 parts 16-26 mesh quartz sand; 8 parts water; and 1 part ultra-high dispersant.

[0021] Example 1 This embodiment proposes a method for preparing an ultra-high dispersant adapted to the UHPC system with esterified grafted crown ether side chains, which includes the following: First, 10 g of glycerol and 42.9 g of anhydrous dichloromethane were added to a dry three-necked flask and stirred to dissolve. The mixture was then heated to 5°C in an ice bath, and 0.1 g of triethylamine was added and stirred for 15 min. 11.35 g of methacryloyl chloride was slowly added dropwise over 2 h. After the addition was complete, the temperature was raised to 35°C and the mixture was stirred at this temperature for 1.5 h. After the reaction was complete, the mixture was washed three times with deionized water. The organic phase was separated, dissolved under reduced pressure, and dried under vacuum for 2 h to obtain glycerol with double bonds.

[0022] 5g of glycerol with double bonds, 125g of HO-PEG-Br, and 260.25g of anhydrous N,N-dimethylformamide were added to a three-necked flask and stirred until homogeneous. Then, 0.05g of anhydrous sodium carbonate and 0.075g of hydroquinone were added. The mixture was heated to 35°C and stirred at a constant temperature for 2.5h to obtain a comb-like intermediate with PEG side chains.

[0023] 20 g of the obtained comb-like intermediate and 5.8 g of 4-carboxybenzo-15-crown-5 were added to a three-necked flask and stirred to dissolve. 0.2 g of 1-ethyl-3-dimethylaminopropylcarbodiimide was then added, and the mixture was stirred at 40 °C for 2 h. After the reaction was complete, the mixture was washed three times with deionized water, and the organic phase was separated and dissolved under reduced pressure to obtain the comb-like side-chain monomer with crown ether.

[0024] Finally, 40.19 g of deionized water was added to a three-necked flask, and the temperature was maintained at 25°C. 0.2 g of hydrogen peroxide and 20 g of comb-shaped side-chain monomers were added and stirred thoroughly. At one end of the flask, 10 g of an aqueous solution consisting of 0.2 g of ascorbic acid and 0.3 g of mercaptoacetic acid was added dropwise; at the other end, 10 g of an aqueous solution consisting of 2.18 g of acrylic acid and 3.9 g of unsaturated 2-hydroxyethyl methacrylate phosphate was added dropwise over 2 hours. After the addition was complete, the reaction was continued at a constant temperature for 3 hours. After the reaction was complete, the pH was adjusted to 8 with sodium hydroxide aqueous solution to obtain a 40% (w / w) comb-shaped crown ether dispersant.

[0025] Example 2 This embodiment proposes a method for preparing an ultra-high dispersant adapted to the UHPC system with esterified grafted crown ether side chains, which includes the following: First, 10 g of glycerol and 27.16 g of anhydrous dichloromethane were added to a dry three-necked flask and stirred to dissolve. The mixture was then heated to 5°C in an ice bath, and 0.15 g of triethylamine was added and stirred for 15 min. 5.67 g of methacryloyl chloride was slowly added dropwise over 2 h. After the addition was complete, the temperature was raised to 35°C and the mixture was stirred at this temperature for 1.5 h. After the reaction was complete, the mixture was washed three times with deionized water. The organic phase was separated, dissolved under reduced pressure, and dried under vacuum for 2 h to obtain glycerol with double bonds.

[0026] 5g of glycerol with double bonds, 125g of HO-PEG-Br, and 260.25g of anhydrous N,N-dimethylformamide were added to a three-necked flask and stirred until homogeneous. Then, 0.075g of anhydrous sodium carbonate and 0.1g of hydroquinone were added. The mixture was heated to 30°C and stirred at a constant temperature for 2.5h to obtain a comb-like intermediate with PEG side chains.

[0027] 20 g of the obtained comb-like intermediate and 8.75 g of 4-carboxybenzo-15-crown-5 were added to a three-necked flask and stirred to dissolve. 0.2 g of 1-ethyl-3-dimethylaminopropylcarbodiimide was then added, and the mixture was heated to 50 °C and stirred for 2 h. After the reaction was complete, the mixture was washed three times with deionized water, and the organic phase was separated and dissolved under reduced pressure to obtain the comb-like side-chain monomer with crown ether.

[0028] Finally, 48.56 g of deionized water was added to a three-necked flask, and the temperature was controlled at 20°C. 0.3 g of hydrogen peroxide and 20 g of comb-shaped side-chain monomers were added and stirred until homogeneous. At one end of the flask, 10 g of an aqueous solution consisting of 0.4 g of ascorbic acid and 0.3 g of mercaptoacetic acid was added dropwise; at the other end, 10 g of an aqueous solution consisting of 2.36 g of acrylic acid and 2.79 g of unsaturated 2-hydroxyethyl methacrylate phosphate was added dropwise over 2 hours. After the addition was complete, the reaction was continued at a constant temperature for 3 hours. After the reaction was complete, the pH was adjusted to 7 with sodium hydroxide aqueous solution to obtain a 35% (w / w) comb-shaped crown ether dispersant.

[0029] Example 3 This embodiment proposes a method for preparing an ultra-high dispersant adapted to the UHPC system with esterified grafted crown ether side chains, which includes the following: First, 10g of glycerol and 48g of anhydrous dichloromethane were added to a dry three-necked flask and stirred to dissolve. The temperature was maintained at 3°C ​​in an ice bath, and 0.15g of triethylamine was added and stirred for 15 minutes. Then, 9.08g of methacryloyl chloride was slowly added dropwise over 2 hours. After the addition was complete, the temperature was raised to 30°C and the reaction was stirred at this temperature for 1 hour. After the reaction was complete, the mixture was washed three times with deionized water. The organic phase was separated, dissolved under reduced pressure, and dried under vacuum for 2 hours to obtain glycerol with double bonds.

[0030] 5g of glycerol with double bonds, 187.5g of HO-PEG-Br, and 385.16g of anhydrous N,N-dimethylformamide were added to a three-necked flask and stirred until homogeneous. Then, 0.03g of triethylamine and 0.05g of hydroquinone were added, and the mixture was heated to 37°C and stirred at a constant temperature for 2.5h to obtain a comb-like intermediate with PEG side chains.

[0031] 20 g of the obtained comb-like intermediate and 7.29 g of 4-carboxybenzo-15-crown-5 were added to a three-necked flask and stirred to dissolve. 0.2 g of 1-ethyl-3-dimethylaminopropylcarbodiimide was then added, and the mixture was heated to 42 °C and stirred for 2 h. After the reaction was complete, the mixture was washed three times with deionized water, and the organic phase was separated and dissolved under reduced pressure to obtain the comb-like side-chain monomer with crown ether.

[0032] Finally, 40.82 g of deionized water was added to a three-necked flask, and the temperature was maintained at 25°C. 0.24 g of hydrogen peroxide and 20 g of comb-shaped side-chain monomers were added and stirred thoroughly. At one end of the flask, 10 g of an aqueous solution consisting of 0.22 g of ascorbic acid and 0.3 g of mercaptopropionic acid was added dropwise; at the other end, 10 g of an aqueous solution consisting of 2.96 g of acrylic acid and 3.49 g of unsaturated 2-hydroxyethyl methacrylate phosphate was added dropwise over 2.5 hours. After the addition was complete, the reaction was continued at a constant temperature for 3 hours. After the reaction was complete, the pH was adjusted to 7 with sodium hydroxide aqueous solution to obtain a 40% (w / w) comb-shaped crown ether dispersant.

[0033] Comparative Example 1 Commercially available phosphoric acid-modified UHPC ultra-high dispersant was used as Comparative Example 1.

[0034] Comparative Example 2 Commercially available ordinary polycarboxylate superplasticizer was used as comparative example 2.

[0035] Comparative Example 3 Commercially available aminosulfonic acid high-efficiency water-reducing agent was used as comparative example 3.

[0036] Comparative Test 1. UHPC mortar flowability To investigate the effect of the ultra-high dispersant synthesized in this scheme on the flowability of UHPC, experiments were conducted to determine the effect on the flowability of UHPC mortar in each example at the same dosage. The experiments were carried out according to GB / T8077-2023 "Test Method for Homogeneity of Concrete Admixtures", and the dispersant dosage was the reduced-solids dosage. The test results are shown in Table 1.

[0037] Table 1 UHPC Performance Test Results

[0038] As shown in Table 1, the ultra-high dispersant synthesized in this embodiment has excellent flow properties and fluidity retention. Moreover, its dispersion and retention performance are better than those of the comparative example containing commercially available dispersants. This indicates that the ultra-high dispersant grafted with crown ether side chains has excellent dispersing ability and UHPC adaptability, and can significantly reduce the viscosity of UHPC mixtures and improve their flow properties.

[0039] 2. Compressive strength of UHPC at different ages To investigate the effect of the ultra-high dispersant synthesized in this scheme on the compressive strength of UHPC, specimens were molded according to GB / T 50081-2019. Immediately after molding, the surface was covered with a waterproof film. After demolding, the specimens were cured for 3 days, 7 days and 28 days respectively, and the compressive strength was tested. The test results are shown in Table 2.

[0040] Table 2. Test results of UHPC compressive strength

[0041] As shown in Table 2, the ultra-high dispersant synthesized in this embodiment has a positive effect on the strength development of the UHPC system.

[0042] The above description is only a part of the embodiments of the present invention and does not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made based on the content of the present invention specification, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A highly effective dispersant for UHPC systems with esterified grafted crown ether side chains, characterized in that, Its molecular formula is shown in Formula 1: Formula 1.

2. A method for preparing an ultra-high dispersant adapted to a UHPC system with esterified grafted crown ether side chains, characterized in that, It includes the following steps: (1) Substitution reaction: Glycerol and anhydrous dichloromethane were added to a dry three-necked flask and stirred to dissolve. The temperature was controlled at 0-5℃ in an ice bath. An acid-binding agent was added and stirred for 10-15 min. Methacrylamide chloride was slowly added dropwise for 1-2 h. After the addition was complete, the temperature was raised to 30-45℃ and the reaction was stirred at a constant temperature for 1-1.5 h. After the reaction was completed, deionized water was added and washed 3 times. The organic phase was separated, dissolved under reduced pressure, and dried under vacuum for 1-2 h to obtain glycerol with double bonds. (2) Substitution reaction: The glycerol with double bonds obtained in step (1), hydroxyl polyethylene glycol bromide, and anhydrous N,N-dimethylformamide are added to a three-necked flask, stirred evenly, and a catalyst and polymerization inhibitor are added. The temperature is raised to 30~40℃ and stirred at a constant temperature for 2.5~3h to allow it to undergo a nucleophilic substitution reaction. The hydroxyl group of the glycerol with double bonds acts as a nucleophile to attack the brominated end of the hydroxyl polyethylene glycol bromide, replacing the bromine atom and forming an ether bond to obtain a comb-like intermediate with PEG side chains. (3) Esterification reaction: The comb-shaped intermediate obtained in step (2) and the crown ether compound were added to a three-necked flask, stirred and dissolved, a catalyst was added, the temperature was controlled at 35~50℃, and the reaction was stirred at a constant temperature for 2~2.5h. After the reaction was completed, deionized water was added and washed 3 times. The organic phase was separated and desolvated under reduced pressure to obtain the comb-shaped side chain monomer with crown ether. (4) Copolymerization: Add deionized water to a three-necked flask, control the temperature to 20~30℃, then add oxidant and comb-shaped side chain monomer obtained in step (3), stir evenly, add an aqueous solution of reducing agent and chain transfer agent dropwise to one end of the flask, and add an aqueous solution of unsaturated carboxylic acid and unsaturated phosphoric acid dropwise to the other end for 2~3h. After the dropwise addition is completed, continue the constant temperature reaction for 3~3.5h. After the reaction is completed, adjust the pH to 7~8 with sodium hydroxide aqueous solution to obtain comb-shaped crown ether dispersant.

3. The method for preparing an ultra-high dispersant for a UHPC system adapted to esterified grafted crown ether side chains as described in claim 2, characterized in that, The acid-binding agent mentioned in step (1) is triethylamine, and its dosage is 0.5% to 1.5% of the mass of glycerol; The molar ratio of methacryloyl chloride to glycerol in step (1) is 0.5~1:1; The amount of anhydrous dichloromethane used in step (1) is 2 to 3 times the total mass of glycerol, acid binder and methacryloyl chloride.

4. The method for preparing an ultra-high dispersant for a UHPC system adapted by esterification grafting crown ether side chains as described in claim 2, characterized in that, The hydroxyl polyethylene glycol bromide mentioned in step (2) is HO-PEG-Br, with a molecular weight of 2000; its molar ratio with the glycerol containing the double bond is 2~3:

1. The amount of anhydrous N,N-dimethylformamide used in step (2) is 1.5 to 2 times the total mass of the double-bonded glycerol, hydroxyl polyethylene glycol bromide, catalyst and polymerization inhibitor; The catalyst mentioned in step (2) is one of anhydrous potassium carbonate, anhydrous sodium carbonate, or triethylamine, and its amount is 0.5% to 1.5% of the mass of the glycerol with double bonds; The polymerization inhibitor mentioned in step (2) is 2,6-di-tert-butyl-p-cresol or hydroquinone, and its amount is 1% to 2% of the mass of the glycerol with double bonds.

5. The method for preparing an ultra-high dispersant for a UHPC system adapted by esterification grafting crown ether side chains as described in claim 2, characterized in that, The crown ether compound mentioned in step (3) is one of 3-carboxy-15-crown-5, 4-carboxybenzo-15-crown-5, or 15-crown-5-acetic acid, and its molar ratio with that of the comb-like intermediate is 2~3:1; The catalyst in step (3) is N-hydroxysuccinimide or 1-ethyl-3-dimethylaminopropylcarbodiimide, and its amount is 0.6% to 1.5% of the mass of the comb-shaped intermediate.

6. The method for preparing an ultra-high dispersant for a UHPC system adapted by esterification grafting crown ether side chains as described in claim 2, characterized in that, The oxidant used in step (4) is hydrogen peroxide, and its amount is 0.6% to 1.5% of the mass of the comb-shaped side-chain monomer with crown ether; The reducing agent in step (4) is ascorbic acid, and its amount is 1% to 2% of the mass of the comb-shaped side-chain monomer with crown ether; The chain transfer agent mentioned in step (4) is mercaptoacetic acid or mercaptopropionic acid, and its amount is 1% to 2% of the mass of the comb-shaped side chain monomer with crown ether; The unsaturated phosphoric acid mentioned in step (4) is 2-hydroxyethyl methacrylate phosphate, and the molar ratio of its amount to the comb-shaped side chain monomer with crown ether is 2~4:1; The unsaturated carboxylic acid mentioned in step (4) is acrylic acid, and the molar ratio of its amount to the comb-shaped side chain monomer with crown ether is 2~6:

1.

7. A highly dispersant for UHPC systems with esterified grafted crown ether side chains, characterized in that, It is prepared by the preparation method described in any one of claims 2 to 6.

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