Water-soluble star-comb polymer concrete viscosity reducer and its preparation method

Abstract

The present invention discloses a water-soluble star-comb polymer concrete viscosity reducer and its preparation method, belonging to the field of concrete. The raw materials for preparing the water-soluble star-comb polymer concrete viscosity reducer include, by mass percentage: 20%-40% of monomers, 0.05%-0.80% of initiator PEO-Br 3 0.01%-0.20% of catalyst, 0.05%-0.25% of ligand, 0.001%-0.01% of deactivator, and the balance is water. The water-soluble star-comb polymer concrete viscosity reducer provided by the present invention has a large steric hindrance, many active sites, low viscosity, and excellent viscosity reduction performance.

Description

Technical Field

[0001] The present invention relates to the field of concrete, and particularly to a water-soluble star-comb polymer concrete viscosity reducer and a preparation method thereof. Background Art

[0002] Polymer viscosity reducers have rich branched-chain structures and excellent adsorption properties, enabling high adsorption density and thick adsorption layers of polymers on the surface of cement particles. They can significantly reduce the yield stress and have a lubricating effect, thus playing a role in reducing the viscosity of concrete. Therefore, adding a polymer viscosity reducer is the most effective method to solve problems such as high viscosity and slow flow rate in the practical application of high-strength concrete. The development history of concrete viscosity reducers is only about ten years. Whether in terms of molecular structure, product variety, performance, or viscosity reduction mechanism, they are not rich and perfect enough. Currently, researchers mainly focus on preparing comb-shaped viscosity-reducing polycarboxylate superplasticizers through molecular structure design, but there are often problems such as single molecular structure, uncontrollable structure, and complex preparation processes, which cannot meet the current theoretical and application requirements of concrete. Therefore, there is currently a lack of a viscosity reducer with large steric hindrance, many active sites, and low viscosity. Summary of the Invention

[0003] In view of the above deficiencies in the prior art, the present invention provides a water-soluble star-comb polymer concrete viscosity reducer and a preparation method thereof to solve the problem of the current lack of a viscosity reducer with large steric hindrance, many active sites, and low viscosity.

[0004] To achieve the above object, the present invention provides a water-soluble star-comb polymer concrete viscosity reducer. The raw materials for preparing the water-soluble star-comb polymer concrete viscosity reducer, by mass percentage, include: 20 - 40% of monomers, 0.05 - 0.80% of initiator PEO-Br 3 0.01 - 0.20% of catalyst, 0.05 - 0.25% of ligand, 0.001 - 0.01% of deactivator, and the balance is water.

[0005] Optionally, the initiator PEO-Br 3 has a structure shown in formula (I): (I), where n is 6 or 7.

[0006] Optionally, the monomers include polyether methoxy polyethylene glycol methacrylate, maleic anhydride, and 2-hydroxyethyl methacrylate phosphate.

[0007] Optionally, the molar ratio of polyether methoxy polyethylene glycol methacrylate, maleic anhydride, and 2-hydroxyethyl methacrylate phosphate is 1:(0.5 - 4):(0.01 - 0.1).

[0008] Optionally, the molecular weight of the polyether methoxypolyethylene glycol methacrylate is 1000 - 3000.

[0009] Optionally, the catalyst is copper powder; and / or, the ligand is tris(2-dimethylaminoethyl)amine or tris(2-aminoethyl)amine; and / or, the deactivator is copper bromide.

[0010] Optionally, the chemical structural formula of the water-soluble star-comb polymer concrete viscosity reducer is as shown in formula (II):

[0011] (II), where n, m, b, and y are all non-zero integers.

[0012] To achieve the above object, the present invention also provides a preparation method of the above water-soluble star-comb polymer concrete viscosity reducer, comprising the following steps: S1: Add polyether methoxypolyethylene glycol methacrylate, maleic anhydride, 2-hydroxyethyl methacrylate phosphate, and water into a reactor, stir to dissolve, then add the catalyst copper and copper bromide, add the ligand under constant temperature and vacuum conditions to react, and then add an initiator to initiate the polymerization reaction. After the polymerization reaction occurs, seal the reactor; S2: Stop the reaction after reacting for a specified time under closed conditions, remove the copper powder and divalent copper complex in the reaction system, rotary evaporate and concentrate, precipitate the concentrated solution, and then dry it under vacuum to obtain the star-comb polymer viscosity reducer.

[0013] Optionally, the constant temperature is 20°C to 50°C.

[0014] Optionally, the reaction time for adding the ligand to react is 10 min - 30 min; and / or, the time for reacting to a specified time under closed conditions is 60 min - 240 min.

[0015] Advantages of the present invention: The water-soluble star-comb polymer concrete viscosity reducer provided by the present invention uses a viscosity-reducing polycarboxylate superplasticizer as the arm, and the arm contains a large number of polar groups such as carboxyl groups, hydroxyl groups, and phosphate groups. These polar groups can be adsorbed on the surface of cement particles through electrostatic action; with a three-arm core as the center, it extends into space, making the viscosity-reducing polycarboxylate superplasticizer adsorbed on the surface of cement particles in a star shape; the long hydrophobic side chains and a large number of hydrophobic cores contained in the arm can provide a large steric hindrance for cement particles, so that the cement particles are evenly dispersed, releasing a large amount of flocculated water wrapped therein, thereby reducing the viscosity, improving the fluidity and mechanical properties of the cement paste. The star-comb polymer viscosity reducer has a special structure and performance, with a large steric hindrance, many active sites, and a low viscosity, thereby enhancing its viscosity-reducing performance and realizing the transformation of the molecular structure of the concrete viscosity reducer. The present invention adopts single-electron transfer living radical polymerization (SET-LRP) which is conducive to large-scale production, has a fast polymerization rate and a high monomer conversion rate. Under the condition of room temperature or lower (room temperature), using green solvent water as the reaction medium, a star-comb polymer viscosity reducer with controllable molecular weight is prepared. The polymerization process is energy-saving, environmentally friendly and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0017] Figure 1 It is the infrared spectrogram of an embodiment of the concrete viscosity reducer of the present invention;

[0018] The realization of the purpose, functional features and advantages of the present invention will be further described in conjunction with the embodiments with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0020] Unless otherwise specified, all technical terms and scientific terms used herein have the ordinary meanings in the field to which the claimed subject matter belongs.

[0021] Polymer viscosity reducers have rich branched-chain structures and excellent adsorption properties, enabling high adsorption density and thick adsorption layers of polymers on the surface of cement particles. They can significantly reduce the yield stress and have a lubricating effect, thus playing a role in reducing the viscosity of concrete. Therefore, adding polymer viscosity reducers is the most effective method to solve problems such as high viscosity and slow flow rate in the practical application of high-strength concrete. Concrete viscosity reducers have only a development history of more than ten years. Whether in terms of molecular structure, product variety, performance, or viscosity reduction mechanism, they are not rich and perfect enough. Currently, researchers mainly focus on preparing comb-shaped viscosity-reducing polycarboxylate superplasticizers through molecular structure design, but there are often problems such as single molecular structure, uncontrollable structure, and complex preparation processes, which cannot meet the current theoretical and application requirements of concrete. Therefore, there is currently a lack of a viscosity reducer with a large steric hindrance, many active sites, and low viscosity.

[0022] To solve the above problems, the present invention proposes a water-soluble star-comb polymer concrete viscosity reducer. The raw materials for preparing the water-soluble star-comb polymer concrete viscosity reducer are as follows in mass percentage: monomers 20 - 40%, initiator PEO-Br 3 0.05 - 0.80%, catalyst 0.01 - 0.20%, ligand 0.05 - 0.25%, deactivator 0.001 - 0.01%, and the balance is water.

[0023] Monomers, as the main components of the viscosity reducer, determine the skeleton structure of the polymer and have a decisive impact on the performance of the final product. The initiator is used to initiate the polymerization reaction, and its type and dosage will affect the molecular weight and molecular weight distribution of the polymer. The catalyst accelerates the rate of the polymerization reaction and improves the reaction efficiency. The ligand is used to stabilize the active center of the catalyst and affects the process of the polymerization reaction. The deactivator is used to control the precision of the polymerization reaction and prevent over-polymerization. Water, as a solvent and dispersion medium, helps the polymer to be uniformly dispersed in water.

[0024] These components work together synergistically, enabling the prepared viscosity reducer to reduce the viscosity of concrete, improve its fluidity and construction performance; through molecular structure design, enhance the interaction with cement particles and strengthen the dispersion effect; the synthesis method is controllable, which helps to achieve industrial production.

[0025] The water-soluble star-comb polymer concrete viscosity reducer of this solution has a large steric hindrance, many active sites, and low viscosity, thereby enhancing its viscosity reduction performance and realizing the transformation of the molecular structure of the concrete viscosity reducer.

[0026] Furthermore, the structure of the initiator PEO-Br 3 is shown in formula (I): (I), n is 6 or 7. The branched chain of methoxypolyethylene glycol can participate in the polymerization reaction as an active site due to its special structure, which helps to form star-shaped or comb-shaped polymers with specific structures. This branched chain structure may improve the fluidity and construction performance of concrete by enhancing the dispersibility of cement particles and reducing the apparent viscosity of cement-based materials. It can also endow the viscosity reducer with better thermal stability, enabling it to be used under a wider range of environmental conditions. Due to the spatial structure of the methoxypolyethylene glycol branched chain, a dense adsorption layer may be formed on the surface of cement particles, providing a significant steric hindrance effect, which helps to disperse cement particles. Moreover, it has good water solubility, which can improve the hydrophilicity of the viscosity reducer and facilitate its dispersion and application in aqueous systems. Initiator PEO-Br 3 was self-prepared. The reaction mechanism is the well-known reaction between acyl chloride and hydroxyl group in this field. It has high reaction activity, no side reactions, and is very easy to proceed. The successful preparation of the concrete viscosity reducer polymer also indirectly proves the initiator PEO-Br 3 was successfully prepared.

[0027] Furthermore, the monomers include polyether methoxypolyethylene glycol methacrylate, maleic anhydride, and 2-hydroxyethyl methacrylate phosphate.

[0028] Polyether methoxypolyethylene glycol methacrylate (MPEG-MAA) is a functional monomer of MPEG methacrylate, which has a high esterification rate and a low acid residue. It is applied to synthesize aqueous dispersions, which can improve the hydrophilicity of the viscosity reducer and its dispersibility in aqueous systems.

[0029] Maleic anhydride is an unsaturated dibasic acid that can introduce other monomers through copolymerization reactions to increase the functionality of the polymer. In the viscosity reducer, maleic anhydride can provide unsaturated bonds, which helps to form a polymer network with specific structures and properties, enhance the cement dispersibility of the viscosity reducer, and improve its water-reducing effect.

[0030] 2-Hydroxyethyl methacrylate phosphate has a phosphate group, which can provide good water solubility and emulsifying properties. The introduction of phosphate may enhance the interaction between the viscosity reducer and cement particles, improve its dispersion stability in cement slurries, and thus reduce the viscosity of cement slurries.

[0031] The combined use of these monomers can prepare a star-comb-shaped structure viscosity reducer with excellent viscosity reduction effect and high water-reducing performance, which helps to improve the workability and construction performance of concrete.

[0032] Furthermore, the molar ratio of polyether methoxypolyethylene glycol methacrylate, maleic anhydride, and 2-hydroxyethyl methacrylate phosphate is 1:(0.5 - 4):(0.01 - 0.1). By precisely controlling the polymerization reaction of these monomers, a viscosity reducer with a specific molecular structure and topological morphology can be designed to meet the specific requirements of high-performance concrete.

[0033] Furthermore, the molecular weight of the polyether methoxypolyethylene glycol methacrylate is 1000 - 3000. In some embodiments, the molecular weight of the polyether methoxypolyethylene glycol methacrylate is preferably 1500 - 2500, and more preferably 1800 - 2200.

[0034] Furthermore, the catalyst is copper powder; and / or, the ligand is tris(2-dimethylaminoethyl)amine or tris(2-aminoethyl)amine; and / or, the deactivator is copper bromide.

[0035] The catalyst copper powder can effectively reduce the activation energy of the reaction, accelerate the reaction rate, and improve the synthesis efficiency of the viscosity reducer. Tris(2-dimethylaminoethyl)amine or tris(2-aminoethyl)amine as a ligand has strong basicity and electron-donating ability, which can stabilize the active state of the copper catalyst, prevent its over-reduction or oxidation during the reaction, and thus improve the stability and service life of the catalyst. In addition, such ligands can also regulate the molecular weight distribution and structure of the polymer by forming stable metal-ligand complexes, thereby improving the performance of the viscosity reducer. Copper bromide as a deactivator is used to control the reaction rate and improve the uniformity of the molecular weight distribution of the product. Copper bromide can be used as a deactivator in single-electron transfer living radical polymerization (SET-LRP) to effectively control the polymerization reaction by adjusting the concentration of active species, achieving precise control of the molecular weight and molecular weight distribution of the viscosity reducer.

[0036] Furthermore, the chemical structural formula of the water-soluble star-comb polymer concrete viscosity reducer is as shown in Formula (II): (II), where n, m, b, and y are all non-zero integers.

[0037] Using the viscosity-reducing polycarboxylate superplasticizer as the arm, the arm contains a large number of polar groups such as carboxyl, hydroxyl, and phosphate groups. These polar groups can be adsorbed on the surface of cement particles through electrostatic action; with the three-arm core as the center, extending into space, the viscosity-reducing polycarboxylate superplasticizer is adsorbed on the surface of cement particles in a star shape; the long hydrophobic side chains and a large number of hydrophobic cores contained in the arm can provide a large steric hindrance for cement particles, so that the cement particles are evenly dispersed, releasing a large amount of flocculated water wrapped therein, thereby reducing the viscosity and improving the fluidity and mechanical properties of the cement paste.

[0038] To solve the above problems, the present invention also provides a method for preparing the above-mentioned water-soluble star-comb polymer concrete viscosity reducer, comprising the following steps:

[0039] S1: Add polyether methoxypolyethylene glycol methacrylate, maleic anhydride, 2-hydroxyethyl methacrylate phosphate and water into a reactor, stir and dissolve them, then add catalysts copper and copper bromide, and add a ligand under the conditions of constant temperature and vacuum to react. Then add an initiator to initiate the polymerization reaction. After the polymerization reaction occurs, seal the reactor;

[0040] In some embodiments, add the unsaturated polyether methoxypolyethylene glycol methacrylate, maleic anhydride, 2-hydroxyethyl methacrylate phosphate, and a certain amount of solvent water into a reactor equipped with a mechanical stirring device, stir and dissolve them, and then add catalysts copper and copper bromide. Place the reaction device in a constant temperature water bath, introduce an inert gas into the reactor to remove oxygen in the reaction system, add a certain amount of ligand tris(2-dimethylaminoethyl)amine, react for several minutes, and then add an initiator PEO-Br 3 Initiate the polymerization reaction. After the polymerization reaction occurs, quickly seal the reactor.

[0041] S2: Stop the reaction after reacting for a specified time under closed conditions, remove copper powder and divalent copper complexes from the reaction system, and concentrate by rotary evaporation. Precipitate the concentrated solution and then dry it under vacuum to obtain the star-comb polymer viscosity reducer.

[0042] In some embodiments, stop the reaction after reacting for a specified time under closed conditions, pass through a neutral alumina column to remove copper powder and divalent copper complexes from the reaction system, and rotary evaporate the filtrate with a rotary evaporator. Finally, precipitate the concentrated solution with petroleum ether, and dry the obtained precipitate under vacuum to obtain the star-comb polymer viscosity reducer.

[0043] Further, the constant temperature is 20°C to 50°C.

[0044] Further, the reaction time for adding the ligand to react is 10 min - 30 min; and / or, the time for reacting to a specified time under closed conditions is 60 min - 240 min. Reasonably controlling the reaction temperature and time is beneficial to controlling the reaction process and obtaining the target product.

[0045] The following further details the present invention with specific embodiments.

[0046] Example 1:

[0047] Weigh 40.0000 g of polyether methoxy polyethylene glycol methacrylate, 5.8800 g of maleic anhydride, 0.2280 g of 2-hydroxyethyl methacrylate phosphate, and 138.4320 g of water and put them into a reaction flask equipped with a stirring device. Place the reactor in a constant temperature water bath (25 ± 1 °C). After stirring and dissolving, add 0.03689 g of copper powder and 0.0553 g of copper bromide to the reaction flask in sequence. Purge with high-purity nitrogen. After 10 min, remove 0.1383 g of the ligand tris(2-dimethylaminoethyl)amine. After 8 min, quickly add 0.0922 g of the initiator PEO-Br 3 , and after reacting for 3 h under nitrogen protection, stop the reaction. Pass the reaction mixture through a neutral alumina column to remove the copper powder and divalent copper complex in the reaction system. Then, rotary evaporate the filtrate using a rotary evaporator. Finally, precipitate the concentrated solution with petroleum ether, and dry the obtained precipitate under vacuum conditions to obtain a star-comb polymer viscosity reducer.

[0048] Example 2:

[0049] Weigh 40.0000 g of polyether methoxy polyethylene glycol methacrylate, 5.8800 g of maleic anhydride, 0.2280 g of 2-hydroxyethyl methacrylate phosphate, and 138.4320 g of water and put them into a reaction flask equipped with a stirring device. Place the reactor in a constant temperature water bath (35 ± 1 °C). After stirring and dissolving, add 0.03689 g of copper powder and 0.0553 g of copper bromide to the reaction flask in sequence. Purge with high-purity nitrogen. After 10 min, remove 0.1383 g of the ligand tris(2-dimethylaminoethyl)amine. After 8 min, quickly add 0.0922 g of the initiator PEO-Br 3 , and after reacting for 3 h under nitrogen protection, stop the reaction. Pass the reaction mixture through a neutral alumina column to remove the copper powder and divalent copper complex in the reaction system. Then, rotary evaporate the filtrate using a rotary evaporator. Finally, precipitate the concentrated solution with petroleum ether, and dry the obtained precipitate under vacuum conditions to obtain a star-comb polymer viscosity reducer.

[0050] Example 3:

[0051] Weigh 40.0000 g of polyether methoxy polyethylene glycol methacrylate, 7.8400 g of maleic anhydride, 0.4560 g of 2-hydroxyethyl methacrylate phosphate, and 144.8940 g of water and put them into a reaction flask equipped with a stirring device. Place the reactor in a constant temperature water bath (25 ± 1 °C). After stirring and dissolving, add 0.03863 g of copper powder and 0.0579 g of copper bromide to the reaction flask in sequence. Purge with high-purity nitrogen. After 10 min, remove 0.1449 g of the ligand tris(2-dimethylaminoethyl)amine. After 8 min, quickly add 0.0965 g of the initiator PEO-Br 3, after reacting for 3 h under nitrogen protection, the reaction was stopped. The copper powder and divalent copper complex in the reaction system were removed by passing through a neutral alumina column, and the filtrate was rotary evaporated using a rotary evaporator. Finally, the concentrated solution was precipitated with petroleum ether, and the obtained precipitate was dried under vacuum conditions to obtain a star-comb polymer viscosity reducer.

[0052] Example 4:

[0053] Weigh 40.0000 g of polyether methoxypolyethylene glycol methacrylate, 7.8400 g of maleic anhydride, 0.4560 g of 2-hydroxyethyl methacrylate phosphate, and 144.8940 g of water and put them into a reaction flask equipped with a stirring device. Place the reactor in a constant temperature water bath (25 ± 1 °C). After stirring and dissolving, 0.03863 g of copper powder and 0.0579 g of copper bromide were successively added to the reaction flask. High-purity nitrogen was introduced for evacuation. After 10 min, 0.1449 g of the ligand tris(2-aminoethyl)amine was removed. After 8 min, 0.0965 g of the initiator PEO-Br was quickly added 3 , after reacting for 3 h under nitrogen protection, the reaction was stopped. The copper powder and divalent copper complex in the reaction system were removed by passing through a neutral alumina column, and the filtrate was rotary evaporated using a rotary evaporator. Finally, the concentrated solution was precipitated with petroleum ether, and the obtained precipitate was dried under vacuum conditions to obtain a star-comb polymer viscosity reducer.

[0054] Comparative Example 1

[0055] Add 250 g of water and 300 g of polyether macromonomer TPEG with a molecular weight of 2400 to a 1000 mL four-necked round-bottom flask equipped with a thermometer, an electric stirrer, an electric heating mantle, and a peristaltic pump. After stirring and dissolving evenly, a mixed solution of 3.6 g of hydrogen peroxide and 16 g of water was directly added and stirred for 8 minutes to dissolve it completely. A mixed aqueous solution composed of 45 g of acrylic acid and 60 g of water and a mixed solution composed of 1.8 g of ascorbic acid, 2.3 g of mercaptoacetic acid, and 60 g of water were added dropwise within 2 h and 2.5 h respectively, and the addition was carried out at room temperature. After the addition was completed, the reaction was continued for 1.5 h, and a 30% sodium hydroxide solution and dilution water were added to obtain a conventional polycarboxylate water reducer with a pH of 6 - 7 and a concentration of about 45%. Its structural formula is as follows:

[0056] .

[0057] Furthermore, infrared spectrum detection was carried out on Example 1, and the results are shown in Figure 1 , at 1249 cm -1 and 526 cm -1 the stretching vibration peak of C-Br appears, and at 1640 cm -1 the C=O stretching vibration peak is at 2910 cm -1 the -CH2 - stretching vibration peak, 1350 cm -1 The C-O stretching vibration peak is at 1249 cm -1 The P=O stretching vibration peak is at 3472 cm -1 The -OH stretching vibration peak is at 1089 cm, indicating that this polymer is obtained by living polymerization. -1 The framework vibration peak of quaternary carbon atoms is at, proving that the polymer has a star structure.

[0058] The above Examples 1 to 4 and Comparative Example 1 were used to measure the fluidity of neat cement paste according to GB / T 8077-2012 "Test Methods for Homogeneity of Concrete Admixtures", and the performance tests of concrete mixtures were carried out with reference to GB / T 50080-2002 "Standard Test Methods for Performance of Ordinary Concrete Mixtures". The cement used was reference cement. The test results are shown in Table 1.

[0059] Table 1 Experimental Results of C50 Concrete

[0060]

[0061] In the experiment of C50 concrete, by comparing the results of different examples and comparative examples, it can be clearly seen that the viscosity reducer of Example 3 performs best in multiple key performance indicators. Specifically, the viscosity of the cement paste in Example 3 is significantly lower than that of other groups, indicating that it is the most effective in reducing viscosity; at the same time, the high values of the slump and slump expansion of the concrete further confirm its excellent fluidity and expandability. In addition, Example 3 also shows the shortest time in the flow-out time of the slump cone, which is directly related to the construction performance of the concrete. In terms of strength development, the compressive strengths of Example 3 at 3 days, 7 days and 28 days are higher than those of other experimental groups, showing good early and long-term strength growth. Considering these results comprehensively, the viscosity reducer of Example 3 not only provides convenience during the construction process, but also performs excellently in ensuring the long-term stability and durability of the concrete structure, making it an optimal admixture in the production of high-performance concrete.

[0062] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A water-soluble star-comb polymer concrete viscosity reducer, characterized in that: The raw materials for preparing the water-soluble star-comb polymer concrete viscosity reducer include, by mass percentage, 20%-40% monomer, 0.05%-0.80% initiator PEO-Br3, 0.01%-0.20% catalyst, 0.05%-0.25% ligand, 0.001%-0.01% deactivator, and the balance water; The monomers include polyether methoxy polyethylene glycol methacrylate, maleic anhydride and hydroxyethyl methacrylate phosphate; The molar ratio of the polyether methoxy polyethylene glycol methacrylate, the maleic anhydride, and the hydroxyethyl methacrylate phosphate is 1:(0.5-4):(0.01-0.1); The structure of the initiator PEO-Br3 is shown in formula (I): (I), n is 6 or 7; The catalyst is copper powder; The ligand is tris(2-dimethylaminoethyl)amine or tris(2-aminoethyl)amine; The deactivating agent is copper bromide.

2. The water-soluble star-comb polymer concrete viscosity reducer according to claim 1, characterized in that: The molecular weight of the polyether methoxy polyethylene glycol methacrylate is 1000-3000.

3. The water-soluble star-comb polymer concrete viscosity reducer according to claim 1, characterized in that: The chemical structural formula of the water-soluble star-comb polymer concrete viscosity reducer is as shown in formula (II): (II), Among them, n, m, b, and y are all non-zero integers.

4. A method for preparing a water-soluble star-comb polymer concrete viscosity reducer, characterized in that: The following steps are involved: S1: Add polyether methoxy polyethylene glycol methacrylate, maleic anhydride, hydroxyethyl methacrylate phosphate and water into a reactor and stir to dissolve, then add catalyst copper and copper bromide, add ligand to react under constant temperature and vacuum conditions, then add initiator to initiate polymerization, and after the polymerization reaction occurs, seal the reactor; S2: After the reaction is carried out under closed conditions for a specified time, the reaction is stopped, the copper powder and the divalent copper complex in the reaction system are removed, and the reaction is concentrated by rotary evaporation, and the concentrated solution is precipitated and vacuum dried to obtain a star-shaped-comb-shaped polymer viscosity reducer; The ligand includes tris(2-dimethylaminoethyl)amine or tris(2-aminoethyl)amine; The initiator includes PEO-Br3, and the structure is shown in formula (I): (I), n is 6 or 7.

5. The method for preparing the water-soluble star-comb polymer concrete viscosity reducer according to claim 4, characterized in that: The constant temperature is 20°C to 50°C.

6. The method for preparing the water-soluble star-comb polymer concrete viscosity reducer according to claim 4, characterized in that: The reaction time of adding the ligand reaction is 10min-30min; And / or, the time for reacting under closed conditions to a specified time is 60 min-240 min.

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