EPEG type polycarboxylic acid water reducing agent and preparation method thereof

Abstract

The application relates to the technical field of concrete admixtures, in particular to an EPEG type polycarboxylate water reducing agent and a preparation method thereof. The EPEG type polycarboxylate water reducing agent is prepared through copolymerization of ethylene glycol monovinyl polyethylene glycol ether, a first unsaturated carboxylic acid and a functional monomer XS under the action of an initiator and a chain transfer agent. The EPEG type polycarboxylate water reducing agent provided by the application has excellent water reducing effect and good adaptability. The EPEG type polycarboxylate water reducing agent is synthesized by adopting a normal-temperature free radical solution copolymerization synthesis technology, the preparation process does not need heating, the preparation steps are simple, raw materials are easy to obtain, and the equipment is conventional, so that the actual industrial application requirements can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete admixtures, in particular to an EPEG type polycarboxylate superplasticizer and a preparation method thereof. BACKGROUND

[0002] With the development of the times, the infrastructure construction at home and abroad gradually increases, the engineering quantity continuously expands, and the demand for various raw materials and admixtures of cement concrete used in engineering is also increasing. As a high-performance concrete admixture, polycarboxylate superplasticizer is widely used in the construction industry due to its excellent water-reducing effect and good adaptability.

[0003] As a high-performance concrete admixture, polycarboxylate superplasticizer is widely used in the construction industry due to its excellent water-reducing effect and good adaptability. However, the traditional polycarboxylate superplasticizer has problems such as high dosage requirement and poor aggregate adaptability under certain conditions, such as poor quality of sand and gravel in raw materials, high clay content, etc., and its adaptability still needs to be improved.

[0004] In recent years, EPEG (ethylene glycol monovinyl polyethylene glycol ether) as a new type of synthetic polycarboxylate superplasticizer polyether macromonomer, due to its unique molecular structure and reactivity, compared with other types of synthetic polycarboxylate superplasticizer polyether macromonomer, its synthetic polycarboxylate superplasticizer shows better water-reducing effect and better adaptability. However, the adaptability improvement effect of the existing EPEG type polycarboxylate superplasticizer is still not ideal, and its water-reducing effect still needs to be improved.

[0005] Therefore, it is of great significance to develop an EPEG type polycarboxylate superplasticizer with excellent water-reducing effect and good adaptability for the development of the construction industry. SUMMARY

[0006] To solve the problems of the prior art mentioned in the background, the present application provides an EPEG type polycarboxylate superplasticizer, and the technical scheme is as follows:

[0007] The EPEG type polycarboxylate superplasticizer is prepared by copolymerization of ethylene glycol monovinyl polyethylene glycol ether, a first unsaturated carboxylic acid and a functional monomer XS under the action of an initiator and a chain transfer agent; the functional monomer XS has the following structural formula:

[0008] ;

[0009] wherein, R1 is H or CH3.

[0010] In some embodiments, the functional monomer XS is prepared by adding 3-(3- aminophenoxy)propyl trimethoxysilane and a second unsaturated carboxylic acid into a reactor to form a mixture, wherein the molar ratio of 3-(3-aminophenoxy)propyl trimethoxysilane to the second unsaturated carboxylic acid is (1.0-1.2):1; adding an organic solvent and a catalyst into the mixture under a protective atmosphere; heating to 40-60°C for 3-6h under the action of the catalyst; and finally filtering and removing the organic solvent to obtain the functional monomer XS.

[0011] It should be noted that the amount of organic solvent is determined according to the dispersibility of 3-(3-aminophenoxy)propyl trimethoxysilane and the second unsaturated carboxylic acid in the solvent and the reaction thereof, and the amount of organic solvent is not limited too much because the solvent is removed by rotary evaporation later.

[0012] In some embodiments, the second unsaturated carboxylic acid is at least one of acrylic acid and methacrylic acid.

[0013] In some embodiments, the organic solvent is at least one of dichloromethane, trichloromethane, methyl acetate, and tetrahydrofuran.

[0014] In some embodiments, the catalyst is at least one of 4-dimethylaminopyridine (DMAP), dicyclohexyl carbodiimide (DCC), pyridine, and imidazole.

[0015] In some embodiments, the protective atmosphere is N2 atmosphere.

[0016] In some embodiments, the reaction liquid is subjected to suction filtration to obtain a filtrate, and then the filtrate is subjected to rotary evaporation to remove the organic solvent to obtain the functional monomer XS.

[0017] In some embodiments, the ethylene glycol monovinyl polyethylene glycol ether, the first unsaturated carboxylic acid, and the functional monomer XS are subjected to a copolymerization reaction under the action of an initiator and a chain transfer agent to obtain an EPEG-type polycarboxylic acid water reducer; wherein the copolymerization reaction temperature is 15-35°C; and the weight ratio of the ethylene glycol monovinyl polyethylene glycol ether, the first unsaturated carboxylic acid, and the functional monomer XS is 200:(6-12):(8-16).

[0018] In some embodiments, the initiator is composed of a reducing agent and an oxidizing agent; the copolymerization process is: dissolving the ethylene glycol monovinyl polyethylene glycol ether in a certain amount of water; controlling the temperature of the reaction system at 15-35℃, and then adding the oxidizing agent and stirring uniformly; then maintaining the temperature of the reaction system at 15-35℃, adding liquid A and liquid B for constant temperature reaction; after the addition is completed, maintaining the temperature of the reaction system at 15-35℃ for 0.5-1h; finally, adding a neutralizing agent to adjust the pH to 5.5-6.5, to obtain the EPEG type polycarboxylic acid water reducer; wherein, the functional monomer XS, the first unsaturated carboxylic acid and a part of water are uniformly mixed to prepare the liquid A; the chain transfer agent, the reducing agent and a part of water are uniformly mixed to prepare the liquid B.

[0019] In some embodiments, the liquid A and the liquid B are added by dropwise addition, and the dropwise addition time is 0.5-2h.

[0020] In some embodiments, the raw material formula of the copolymerization reaction is, by weight fraction: ethylene glycol monovinyl polyethylene glycol ether 200 parts, functional monomer XS 8-16 parts, first unsaturated carboxylic acid 6-12 parts, oxidizing agent 0.5-2.0 parts, reducing agent 0.1-0.5 parts, chain transfer agent 0.4-1.4 parts, and total amount of water 196-218 parts.

[0021] In some embodiments, the molecular weight of the ethylene glycol monovinyl polyethylene glycol ether is 1500-3000.

[0022] In some embodiments, the first unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, and maleic anhydride.

[0023] In some embodiments, the oxidizing agent is at least one of a hydrogen peroxide solution with a mass concentration of 27.5%, ammonium persulfate, and sodium persulfate.

[0024] In some embodiments, the chain transfer agent is at least one of sodium hypophosphite, mercaptoacetic acid, and mercaptopropionic acid.

[0025] In some embodiments, the reducing agent is at least one of ascorbic acid, Bruggolite FF6, and Bruggolite E01.

[0026] In some embodiments, the neutralizing agent is a sodium hydroxide solution with a mass concentration of 32%.

[0027] The application also provides a preparation method of the EPEG type polycarboxylic acid water reducer as described above, wherein the initiator includes an oxidizing agent and a reducing agent; the preparation method includes the following preparation steps:

[0028] The ethylene glycol monovinyl polyethylene glycol ether is dissolved in a certain amount of water, the temperature of the reaction system is controlled at 15-35 DEG C, and then an oxidizing agent is added and stirred uniformly to form a mixed solution;

[0029] The functional monomer XS and the first unsaturated carboxylic acid are uniformly mixed with a part of water to prepare A liquid;

[0030] The chain transfer agent and the reducing agent are uniformly mixed with a part of water to prepare B liquid;

[0031] Then the temperature of the reaction system is maintained at 15-35 DEG C, the A liquid and the B liquid are added dropwise in the mixed solution for constant temperature reaction, and the dropwise adding time is 0.5-2 h;

[0032] After the dropwise adding is completed, the reaction system is maintained at 15-35 DEG C for 0.5-1 h, and finally a neutralizing agent is added to adjust the pH to 5.5-6.5 to prepare the EPEG type polycarboxylic acid water reducing agent.

[0033] Compared with the prior art, the EPEG type polycarboxylic acid water reducing agent provided in the application has the following beneficial effects:

[0034] The EPEG type polycarboxylic acid water reducing agent provided in the application has excellent water reducing effect and good adaptability. It is synthesized by normal temperature free radical solution copolymerization technology, the preparation process does not need heating, and the preparation steps are simple, the raw materials are easy to obtain, and the equipment is conventional, which can meet the actual industrial application requirements. DETAILED DESCRIPTION

[0035] To make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are some embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0036] The application also provides the following examples and comparative examples:

[0037] Example 1:

[0038] Preparation of functional monomer XS:

[0039] (1) 148 parts of 3-(3-aminophenoxy)propyl trimethoxysilane and 36 parts of acrylic acid are added in a reactor according to mass parts. The molar ratio of 3-(3-aminophenoxy)propyl trimethoxysilane to acrylic acid is 1.09:1;

[0040] (2) Under N2 atmosphere, 500 mL of tetrahydrofuran is added, and the reaction is carried out at 50°C for 4 h under the catalysis of 4-dimethylaminopyridine (DMAP) to obtain a reaction solution;

[0041] The amount of the catalyst 4-dimethylaminopyridine is 1.36 parts.

[0042] (3) The reaction solution is filtered, and the filtrate is rotary evaporated to remove the organic solvent, thereby obtaining the functional monomer XS.

[0043] Preparation of the EPEG type polycarboxylic acid water reducer:

[0044] (1) 200 parts of ethylene glycol monovinyl polyethylene glycol ether and 150 parts of water are added into a three-necked flask to form a mixed solution under stirring at 15-35°C;

[0045] (2) 13.6 parts of the functional monomer XS, 10 parts of acrylic acid and 28 parts of water are mixed to prepare A liquid;

[0046] (3) 0.6 parts of mercaptoacetic acid, 0.32 parts of ascorbic acid and 32 parts of water are mixed to prepare B liquid;

[0047] (4) 1.5 parts of 27.5% mass concentration hydrogen peroxide is added into the flask and stirred uniformly;

[0048] (5) The A liquid and the B liquid are added dropwise into the three-necked flask under constant temperature at 15-35°C, and the dropping time is 1.5 h;

[0049] (6) After the dropping is completed, the temperature is kept at 15-35°C for 1 h, and then 32% mass concentration sodium hydroxide solution is added into the three-necked flask to adjust the pH value of the mixed solution to 5.5-6.5, thereby obtaining the EPEG type polycarboxylic acid water reducer.

[0050] Example 2:

[0051] Preparation of the functional monomer XS:

[0052] (1) 156 parts of 3-(3-aminophenoxy)propyl trimethoxysilane and 43 parts of methacrylic acid are added into a reactor according to the mass parts, and the molar ratio of 3-(3-aminophenoxy)propyl trimethoxysilane to methacrylic acid is 1.15:1.

[0053] (2) Under N2 atmosphere, 500 mL of tetrahydrofuran is added, and the reaction is carried out at 54°C for 4 h under the catalysis of 4-dimethylaminopyridine (DMAP) to obtain a reaction solution;

[0054] The amount of the catalyst 4-dimethylaminopyridine is 1.45 parts.

[0055] (3) The reaction solution is suction filtered, and the obtained filtrate is rotary evaporated to remove the organic solvent, to obtain the functional monomer XS.

[0056] Preparation of the EPEG type polycarboxylic acid water reducer:

[0057] (1) 200 parts of ethylene glycol monovinyl polyethylene glycol ether and 150 parts of water are added into a three-necked flask, and a mixed solution is formed by stirring at 15-35°C;

[0058] (2) 15.6 parts of the functional monomer XS, 8 parts of acrylic acid, and 30 parts of water are uniformly mixed to prepare A liquid;

[0059] (3) 0.8 parts of sodium hypophosphite, 0.25 parts of Bruggolite FF6, and 30 parts of water are uniformly mixed to prepare B liquid;

[0060] (4) 1.3 parts of hydrogen peroxide with a mass concentration of 27.5% is added into the flask and stirred uniformly;

[0061] (5) The A liquid and the B liquid are respectively added dropwise into the three-necked flask, and the reaction is carried out at a constant temperature of 15-35°C, and the dropwise adding time is 1.5 hours;

[0062] (6) After the dropwise adding is completed, the reaction is kept at 15-35°C for 1 hour, and then a sodium hydroxide solution with a mass concentration of 32% is added into the three-necked flask to adjust the pH value of the mixed solution to 5.5-6.5, to obtain the EPEG type polycarboxylic acid water reducer.

[0063] Comparative Example 1:

[0064] Commercially available EPEG type polycarboxylic acid water reducer Point-T;

[0065] Comparative Example 2: (functional monomer XS is replaced by acrylic acid)

[0066] The difference from Example 1 is that the functional monomer XS in Example 1 is replaced by acrylic acid in equal mass, and the rest is consistent with Example 1.

[0067] Comparative Example 3: (functional monomer XS is replaced by acrylamide)

[0068] The difference from Example 1 is that the functional monomer XS in Example 1 is replaced by acrylamide in equal mass, and the rest is consistent with Example 1.

[0069] Comparative Example 4: (functional monomer XS is replaced by vinyl trimethoxysilane)

[0070] The difference from Example 1 is that the functional monomer XS in Example 1 is replaced by vinyl trimethoxysilane in equal mass, and the rest is consistent with Example 1.

[0071] Comparative Example 5: (the ratio of the first unsaturated carboxylic acid and the functional monomer XS exceeds the range)

[0072] The difference from Example 1 is that, during the copolymerization reaction, 200 parts of ethylene glycol monovinyl polyethylene glycol ether, 15 parts of acrylic acid, and 19 parts of functional monomer XS are used, and the rest is consistent with Example 1.

[0073] Performance testing of the examples and comparative examples:

[0074] In order to further illustrate the performance effect of the EPEG type polycarboxylic acid water reducing agent provided in the present application, according to the standard GB 8076-2008 "Concrete Admixture", the products prepared in the above examples and comparative examples are tested for the working performance of cement concrete; under the same compounding conditions, the water reducing agent dosage is 0.18%, the concrete mix proportion is as shown in Table 1, and the concrete performance test results are as shown in Table 2:

[0075] Table 1: Concrete mix proportion (unit: kg / m3)

[0076] Cement Fly ash (class II) Slag (S95) Machine-made sand (MB = 2.2) Crushed stone Water 2.9 0.4 0.3 9.2 9.5 1.6

[0077] Among them, the MB of machine-made sand is 2.2, indicating that the quality of machine-made sand in the concrete is poor, and the concrete is prepared by poor raw materials, so as to reflect the good adaptability of the polycarboxylic acid water reducing agent of the present application.

[0078] Table 2: Concrete working performance test

[0079]

[0080] The experimental results show that:

[0081] Under the condition of the same dosage, the water reducing effect and adaptability of the polycarboxylic acid water reducing agent of the examples prepared in the present application are better than those of Comparative Examples 1-5.

[0082] In Comparative Example 1, the existing EPEG polycarboxylic acid water reducing agent has poor water reducing effect, poor concrete state, low compressive strength, and poor adaptability.

[0083] In Comparative Example 2, after replacing the functional monomer XS with acrylic acid, the water reducing effect is poor, the concrete state is poor, the compressive strength is low, and the adaptability is poor.

[0084] In Comparative Example 3, after replacing the functional monomer XS with acrylamide, the water reducing effect is significantly reduced, the concrete state is general, and the adaptability is poor.

[0085] In Comparative Example 4, after replacing the functional monomer XS with vinyl trimethoxysilane, the loss over time is significantly accelerated, the concrete state is general, and the adaptability is poor.

[0086] In the comparative example 5, the use amount of the first unsaturated carboxylic acid and the functional monomer XS exceeds the recommended amount in the technical solution, and the imbalance of monomer ratio easily affects the polymerization process, and then causes the change of the molecular weight and distribution of the polymer, and at the same time, the imbalance of the hydrophobicity and hydrophilicity of the polymer chain segment affects the stability and dispersibility of the polymer, and is not conducive to the free distribution of the water reducing agent molecules on the cement particles, and the water reducing effect is significantly reduced.

[0087] In summary, the EPEG type polycarboxylic acid water reducing agent provided by the application has at least the following design concepts and beneficial effects:

[0088] 1. The EPEG type polycarboxylic acid water reducing agent provided by the application has excellent water reducing effect, which is because the research process effectively improves the adsorption and dispersion performance of the water reducing agent in the cement environment. The alkoxyl group of the silane in the water reducing agent molecule produces silanol through hydrolysis, and chemical adsorption is generated on the surface of the cement particles to form a stable film, which reduces the interaction force between the cement particles and reduces the viscosity and yield stress of the cement slurry. At the same time, the rigid hydrophobic structure of the benzene ring can reduce the hydrogen bond interaction between the EPEG polyether side chain and the interlayer of montmorillonite, and further prevent the aggregation and sedimentation of the cement particles by combining the steric hindrance effect, and release the free water wrapped, and increase the fluidity of the concrete.

[0089] 2. The EPEG type polycarboxylic acid water reducing agent provided by the application has good adaptability, which is because the amide group in the introduced functional monomer XS slowly releases more carboxylic acid groups in the alkaline environment of the concrete, which guarantees the good fluidity state of the concrete. At the same time, the amide group can accelerate the dissolution of tricalcium silicate and the crystallization of the hydration product, and improve the early strength of the concrete. And the silane can improve the pore structure of the concrete, reduce the penetration and erosion of harmful substances, and improve the durability of the concrete.

[0090] 3. The EPEG type polycarboxylic acid water reducing agent provided by the application is prepared by introducing the functional monomer XS and copolymerizing with ethylene glycol monovinyl polyethylene glycol ether and the first unsaturated carboxylic acid, wherein each copolymer monomer synergistically acts, and is not simply functionally superimposed, and the structure selection and proportion design of each monomer will affect the structure of the finally obtained polycarboxylic acid water reducing agent, thereby affecting its performance and effect. For example, the ratio of ethylene glycol monovinyl polyethylene glycol ether, functional monomer XS and the first unsaturated carboxylic acid is not within the limited range of the application, then the molecular structure of the polycarboxylic acid water reducing agent does not match the expected design, and the water reducing effect is poor.

[0091] 4. The EPEG polycarboxylate superplasticizer provided by the present application introduces functional monomer XS, thereby introducing silane alkoxy, amide groups and the like into the superplasticizer to play the corresponding effect. However, simply introducing silane alkoxy and amide groups into the superplasticizer molecule cannot achieve the effect of the present application. Specifically, how to introduce silane alkoxy, amide groups and the like (whether different groups are introduced by different monomers or multiple groups are integrated into a functional monomer to participate in polymerization), and the specific structure of the functional monomer used for participating in polymerization which integrates silane alkoxy and amide groups, will result in different side chain structures of the obtained polycarboxylate superplasticizer, thereby resulting in different molecular structures of the superplasticizer, and ultimately affecting its performance and effect.

[0092] The present application adopts a functional monomer XS which integrates alkoxy, amide groups and the like with a specific structure, and then introduces the functional monomer XS with the specific structure into the side chain of the polycarboxylate superplasticizer through copolymerization reaction, so as to obtain the required structure of the polycarboxylate superplasticizer and achieve the required effect of the present application.

[0093] If the unsaturated amide monomer containing amide groups and the silane monomer containing alkoxy groups are respectively used as copolymerization monomers to copolymerize with ethylene glycol monovinyl polyethylene glycol ether, unsaturated carboxylic acid monomers and the like, due to the differences in reactivity and solubility of each monomer with different groups, competitive reactions are caused, the side chain of the polycarboxylic acid is a structure with uneven distribution of each group, which is different from the structure with balanced distribution of each group in the side chain of the present application, and thus the structure of the obtained polycarboxylic acid superplasticizer is different, and the present application cannot achieve the effect.

[0094] For example, the scheme disclosed in patent publication CN116041630A copolymerizes ethylene glycol monovinyl polyethylene glycol ether, unsaturated amide monomer, unsaturated carboxylic acid monomer, unsaturated sulfonate, silane monomer, chloroallyl dimethyl phosphate and quaternary ammonium salt polyether ester monomer at 10-15°C to prepare an EPEG polycarboxylic acid superplasticizer. However, the scheme does not provide corresponding superplasticizer adaptability effect proof, and the test results show that the superplasticizer has good water reducing performance in a conventional raw material formula.

[0095] 5. The EPEG polycarboxylic acid superplasticizer provided by the present application has excellent compatibility with polycarboxylic acid molecules, and can be used independently or in combination with conventional superplasticizers, which has significant market potential.

[0096] 6. The EPEG polycarboxylic acid superplasticizer provided by the present application can be prepared at room temperature, and the process is simple and mild, without the need for complex temperature control steps, low energy consumption, and high production and practical value.

[0097] In summary, the application introduces unsaturated amide phenyl silane functional monomer XS, and can be used in conjunction with part of common unsaturated carboxylic acid, to prepare EPEG type polycarboxylic acid water reducing agent with excellent water reducing effect, good adaptability and meeting the needs of actual industrial application by using normal temperature free radical solution copolymerization technology without heating.

[0098] It should be noted that:

[0099] EPEG is the abbreviation of ethylene glycol monovinyl polyethylene glycol ether.

[0100] In this paper, "~" is used to represent the numerical range, and the range represented by this expression includes both end point values.

[0101] In addition to the actual choices embodied in the above specific embodiments, the above formula range can be used in the specific implementation of the application, including but not limited to the above embodiment scheme.

[0102] The specific parameters or some commonly used reagents or raw materials in the above examples are specific embodiments or preferred embodiments under the concept of the application, but not limited thereto; those skilled in the art can make adaptive adjustment within the scope of the concept and protection of the application.

[0103] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the application, but not limited thereto; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. An EPEG-type polycarboxylate superplasticizer, characterized in that: It is produced by copolymerization of ethylene glycol monovinyl polyethylene glycol ether, a first unsaturated carboxylic acid and functional monomer XS under the action of an initiator and a chain transfer agent. The structural formula of the functional unit XS is as follows: ； Wherein, R1 is H or CH3; The weight ratio of the ethylene glycol monovinyl polyethylene glycol ether, the first unsaturated carboxylic acid, and the functional monomer XS is 200:(6-12):(8-16).

2. The EPEG-type polycarboxylate superplasticizer according to claim 1, characterized in that: The preparation process of the functional monomer XS is as follows: 3-(3-aminophenoxy)propyltrimethoxysilane and a second unsaturated carboxylic acid are added to a reactor to form a mixture; wherein the molar ratio of 3-(3-aminophenoxy)propyltrimethoxysilane to the second unsaturated carboxylic acid is (1.0–1.2):1; An organic solvent and a catalyst are added to the mixture under a protective atmosphere; the mixture is heated to 40–60°C and reacted for 3–6 hours under the action of the catalyst; finally, the reaction solution is filtered to remove the organic solvent, thereby obtaining the functional monomer XS.

3. The EPEG-type polycarboxylate superplasticizer according to claim 2, characterized in that: The second unsaturated carboxylic acid is at least one of acrylic acid and methacrylic acid; The organic solvent is at least one of dichloromethane, trichloromethane, methyl acetate, and tetrahydrofuran; The catalyst is at least one of 4-dimethylaminopyridine, dicyclohexylcarbodiimide, pyridine, and imidazole.

4. The EPEG-type polycarboxylate superplasticizer according to claim 2, characterized in that: The protective atmosphere is an N2 atmosphere; The reaction solution was filtered to obtain a filtrate, which was then subjected to rotary evaporation to remove the organic solvent, thereby obtaining the functional monomer XS.

5. The EPEG-type polycarboxylate superplasticizer according to claim 1, characterized in that: Under the action of an initiator and a chain transfer agent, the ethylene glycol monovinyl polyethylene glycol ether, the first unsaturated carboxylic acid, and the functional monomer XS are copolymerized to obtain an EPEG-type polycarboxylic acid water-reducing agent; The copolymerization reaction temperature is 15–35°C.

6. The EPEG-type polycarboxylate superplasticizer according to claim 1, characterized in that: The initiator consists of a reducing agent and an oxidizing agent; the copolymerization process is as follows: The ethylene glycol monovinyl polyethylene glycol ether was dissolved in a certain amount of water; the reaction system temperature was controlled at 15-35°C, and then an oxidant was added and stirred evenly; then, the reaction system temperature was maintained at 15-35°C, and solutions A and B were added for constant temperature reaction; after the addition was completed, the reaction system temperature was kept at 15-35°C for 0.5-1 h; finally, a neutralizing agent was added to adjust the pH to 5.5-6.5 to obtain the EPEG type polycarboxylate superplasticizer. Solution A is prepared by uniformly mixing the functional monomer XS, the first unsaturated carboxylic acid, and a portion of water; solution B is prepared by uniformly mixing the chain transfer agent, the reducing agent, and a portion of water.

7. The EPEG-type polycarboxylate superplasticizer according to claim 6, characterized in that: Solution A and solution B are added by dripping over a period of 0.5 to 2 hours. The raw material formulation for the copolymerization reaction, by weight, is as follows: 200 parts of ethylene glycol monovinyl polyethylene glycol ether, 8-16 parts of functional monomer XS, 6-12 parts of the first unsaturated carboxylic acid, 0.5-2.0 parts of oxidant, 0.1-0.5 parts of reducing agent, 0.4-1.4 parts of chain transfer agent, and a total of 196-218 parts of water.

8. The EPEG-type polycarboxylate superplasticizer according to claim 1, characterized in that: The molecular weight of the ethylene glycol monovinyl polyethylene glycol ether is 1500-3000; The first unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, and maleic anhydride.

9. The EPEG-type polycarboxylate superplasticizer according to claim 6, characterized in that: The oxidant is at least one of the following: a 27.5% (w / w) hydrogen peroxide solution, ammonium persulfate, and sodium persulfate. The chain transfer agent is at least one of sodium hypophosphite, mercaptoacetic acid, and mercaptopropionic acid; The reducing agent is at least one of ascorbic acid, Bruggolite FF6, and Bruggolite E01; The neutralizing agent is a 32% sodium hydroxide solution.

10. A method for preparing an EPEG-type polycarboxylate superplasticizer as described in any one of claims 1-9, characterized in that, The initiator includes an oxidizing agent and a reducing agent; the preparation method includes the following preparation steps: The ethylene glycol monovinyl polyethylene glycol ether is dissolved in a certain amount of water, and the temperature of the reaction system is controlled at 15-35°C. Then, an oxidant is added and stirred evenly to form a mixed solution. Solution A is prepared by mixing the functional monomer XS, the first unsaturated carboxylic acid, and a portion of water evenly. Solution B is prepared by mixing the chain transfer agent, the reducing agent and a portion of water evenly. Then, the temperature of the reaction system is maintained at 15-35°C, and solution A and solution B are added dropwise to the mixed solution for a constant temperature reaction over a period of 0.5-2 hours. After the addition is complete, the reaction system is kept at a temperature of 15–35°C for 0.5–1 h. Finally, a neutralizing agent is added to adjust the pH to 5.5–6.5 to obtain the EPEG-type polycarboxylate superplasticizer.

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