High-performance polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention relates to the technical field of concrete admixtures, in particular to a high-performance polycarboxylate superplasticizer and a preparation method thereof. The high-performance polycarboxylate superplasticizer comprises the following components: a polycarboxylate superplasticizer and modified cellulose ether, the polycarboxylate superplasticizer is prepared by polymerization reaction of vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer under the action of initiator and chain transfer agent. According to the high-performance polycarboxylic acid water reducing agent provided by the invention, the polycarboxylic acid water reducing agent and the modified cellulose ether are compounded and applied to concrete, the initial fluidity of the concrete is good, the slump retaining property is good, the water-retaining property, the wrapping property and the cohesiveness of the concrete are good, and the segregation and bleeding phenomena are avoided when the concrete is mixed with the high-performance polycarboxylic acid water reducing agent.

Description

Technical Field

[0001] The present application relates to the technical field of concrete admixtures, and in particular to a high-performance polycarboxylate water-reducing agent and a preparation method thereof. Background Art

[0002] Concrete raw materials have a great influence on concrete performance. Under the same mix ratio, changes in raw materials often cause large differences in concrete performance, especially on the performance of concrete mixtures, which can cause problems such as water seepage and segregation in concrete.

[0003] In addition, high-fluidity cementitious materials, such as self-leveling concrete, self-compacting concrete, grouting materials, etc., show great advantages in engineering applications. The key issue in the preparation of high-fluidity cementitious materials is to achieve high fluidity and stability at the same time, which means achieving high fluidity without any bleeding and segregation.

[0004] In order to ensure the stability of concrete performance, optimizing the performance of concrete mixtures through concrete admixtures is a common technical means, and polycarboxylate water reducer is currently the largest admixture used in concrete and its function can be designed.

[0005] When the raw materials of concrete fluctuate, the existing traditional polycarboxylate water reducer cannot effectively solve its segregation and bleeding problems. In addition, the existing traditional polycarboxylate water reducer cannot effectively solve the segregation and bleeding problems of high-fluidity cement-based materials. Therefore, it is imperative to develop a high-performance polycarboxylate water reducer that can improve concrete segregation and bleeding. Summary of the invention

[0006] In order to solve the problems of the prior art mentioned in the above background technology, the present application provides a high-performance polycarboxylate water-reducing agent, and its technical solution is as follows: The components of the high-performance polycarboxylate water-reducing agent include polycarboxylate water-reducing agent and modified cellulose ether; the polycarboxylate water-reducing agent is prepared by polymerization reaction of vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer under the action of initiator and chain transfer agent; The functional monomer is 3-[tri(1-methylethoxy)silyl]propyl methacrylate or a hydrophobic monomer, and the hydrophobic monomer has the following structural formula: , Wherein, a value is 1 or 2, b value is an integer from 1 to 7, R1 is H or CH3, and R2 is H or F.

[0007] In some embodiments, the weight ratio of the polycarboxylate water-reducing agent to the modified cellulose ether is (60-80): (15-20).

[0008] In some embodiments, the preparation process of the modified cellulose ether is as follows: adding alkali solution to cellulose for alkaline treatment; heating to 60-90°C, adding propylene oxide and reacting at 60-90°C for 1-3h to obtain the modified cellulose ether; wherein the weight ratio of the carboxymethyl cellulose, alkali solution and propylene oxide is 100: (5-20): (20-100), and the mass concentration of the alkali solution is (30-35)%.

[0009] In some embodiments, the cellulose is carboxymethyl cellulose, the molecular weight of which is 90,000 to 250,000 and the degree of substitution is 0.7 to 1.2; and the alkali solution is sodium hydroxide solution.

[0010] In some embodiments, under the action of an initiator and a chain transfer agent, the vinyl polyether macromonomer, unsaturated carboxylic acid, and functional monomer are polymerized to produce a polycarboxylic acid water reducer; wherein the polymerization reaction temperature is 40 to 45° C.; and the weight ratio of the vinyl polyether macromonomer, unsaturated carboxylic acid, and functional monomer is (80 to 100): (10 to 15): (10 to 30).

[0011] In some embodiments, the initiator consists of a reducing agent and an oxidizing agent; The polymerization reaction process is as follows: by weight, 10 to 30 parts of functional monomers, 80 to 100 parts of vinyl polyether macromonomers, 1 to 1.52 parts of oxidants and 50 to 80 parts of water are added to a reactor; the temperature of the reaction system is controlled at 40 to 45° C., and then 30.5 to 30.8 parts of a reducing agent aqueous solution, 40 to 45 parts of an unsaturated carboxylic acid aqueous solution and 30.4 to 30.9 parts of a chain transfer agent aqueous solution are added respectively for 3 to 4 hours; the reducing agent aqueous solution, the unsaturated carboxylic acid aqueous solution and the chain transfer agent aqueous solution are added to the reactor; After the addition of all the liquids is completed, the mixture is kept warm at 40-45°C for 1-5h, and a suitable amount of water is added to adjust the concentration of the reaction product to 40-50%. The pH of the reaction product is adjusted to 6.0-7.0 with an alkali to obtain a polycarboxylic acid water-reducing agent. The unsaturated carboxylic acid aqueous solution is formed by dissolving 10-15 parts of unsaturated carboxylic acid in 30 parts of water; the reducing agent aqueous solution is formed by dissolving 0.5-0.8 parts of reducing agent in 30 parts of water; and the chain transfer agent aqueous solution is formed by dissolving 0.4-0.9 parts of chain transfer agent in 30 parts of water.

[0012] In some embodiments, the reducing agent aqueous solution, the unsaturated carboxylic acid aqueous solution and the chain transfer agent aqueous solution are added dropwise.

[0013] In some embodiments, the molecular weight of the vinyl polyether macromonomer is 2400-5000; and the unsaturated carboxylic acid is acrylic acid.

[0014] In some embodiments, the reducing agent is one or more combinations of bisulfite, sulfite, bleaching agent, and vitamin C; the oxidant is hydrogen peroxide; the chain transfer agent is one or more combinations of mercaptoethanol, thioglycolic acid, mercaptopropionic acid, n-dodecyl mercaptan, secondary dodecyl mercaptan, and tert-dodecyl mercaptan; and the base is sodium hydroxide.

[0015] The present application also provides a method for preparing the high-performance polycarboxylate water-reducing agent as described above, which comprises the following preparation steps: mixing the polycarboxylate water-reducing agent and the modified cellulose ether to obtain the high-performance polycarboxylate water-reducing agent.

[0016] Compared with the existing technology, the high-performance polycarboxylate water-reducing agent provided in this application has the following beneficial effects: The high-performance polycarboxylate water-reducing agent provided in the present application is a composite of a polycarboxylate water-reducing agent and a modified cellulose ether, which is applied to concrete. The concrete has good initial fluidity, good slump retention performance, and good water retention, encapsulation and cohesion. There is no segregation and bleeding phenomenon in the mixed concrete. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] The present application also provides the following embodiments and comparative examples: Example 1 1. The preparation process of polycarboxylate water reducer is: 30 g of 2,2,3,3-tetrafluoropropyl methacrylate, 85 g of ethylene glycol monovinyl polyglycol ether, 2 g of hydrogen peroxide and 50 g of water were added to a reaction kettle; The temperature was controlled at 40°C, and then the vitamin C aqueous solution, acrylic acid aqueous solution and thioglycolic acid aqueous solution were added dropwise at a uniform speed for 3 hours. After the addition was completed, the mixture was kept at 40°C for 1 hour, and a suitable amount of water was added to adjust the concentration of the reaction product to 50%. The pH of the reaction product is adjusted to 6.0-7.0 with sodium hydroxide to obtain a polycarboxylate water reducer; The acrylic acid aqueous solution is 15 g of acrylic acid solution dissolved in 30 g of water, the vitamin C aqueous solution is 0.7 g of vitamin C dissolved in 30 g of water, the thioglycolic acid aqueous solution is 0.5 g of thioglycolic acid dissolved in 30 g of water, and the molecular weight of ethylene glycol monovinyl polyethylene glycol ether is 3,000.

[0019] 2. The preparation process of modified cellulose ether is: 8 g of 32% sodium hydroxide solution was added to 100 g of carboxymethyl cellulose for alkaline treatment, the temperature was raised to 60°C, and 20 g of propylene oxide was added, and the reaction was carried out at 60°C for 1 hour to obtain modified cellulose ether.

[0020] Among them, the molecular weight of carboxymethyl cellulose is 90,000 and the degree of substitution is 0.7.

[0021] 3. The preparation process of high performance polycarboxylate water reducer is: 75 g of polycarboxylate water reducer was blended with 20 g of modified cellulose ether to obtain a high-performance polycarboxylate water reducer.

[0022] Example 2 1. The preparation process of polycarboxylate water reducer is: 20 g of 1H,1H,2H,2H-perfluorodecyl acrylate, 90 g of butanediol monovinyl polyethylene glycol ether, 1.2 g of hydrogen peroxide, and 60 g of water were added to a reaction kettle; The temperature was controlled at 45°C, and then the aqueous solution of bleaching powder, the aqueous solution of acrylic acid and the aqueous solution of mercaptopropionic acid were added dropwise at a uniform speed for 3 hours. After the addition was completed, the temperature was kept at 45°C for 1 hour, and an appropriate amount of water was added to adjust the concentration of the reaction product to 50%; The pH of the reaction product is adjusted to 6.0-7.0 with sodium hydroxide to obtain a polycarboxylate water reducer; The acrylic acid aqueous solution is 14 g of acrylic acid solution dissolved in 30 g of water. The bleaching agent aqueous solution is 0.8 g of bleaching agent dissolved in 30 g of water. The mercaptopropionic acid aqueous solution is 0.7 g of mercaptopropionic acid dissolved in 30 g of water. The molecular weight of butanediol monovinyl polyethylene glycol ether is 2400.

[0023] 2. The preparation process of modified cellulose ether is: 10 g of 32% sodium hydroxide solution was added to 100 g of carboxymethyl cellulose for alkaline treatment, the temperature was raised to 70°C, and 50 g of propylene oxide was added, and the reaction was carried out at 70°C for 2 hours to obtain modified cellulose ether.

[0024] Among them, the molecular weight of carboxymethyl cellulose is 250,000 and the degree of substitution is 1.2.

[0025] 3. The preparation process of high performance polycarboxylate water reducer is: 80 g of polycarboxylate water reducer was blended with 20 g of modified cellulose ether to obtain a high-performance polycarboxylate water reducer.

[0026] Example 3 1. The preparation process of polycarboxylate water reducer is: 15 g of 3-[tri(1-methylethoxy)silyl]propyl methacrylate, 85 g of ethylene glycol monovinyl polyglycol ether, 1.4 g of hydrogen peroxide and 80 g of water were added to a reaction kettle; The temperature was controlled at 40°C, and then the vitamin C aqueous solution, acrylic acid aqueous solution and thioglycolic acid aqueous solution were added dropwise at a uniform speed for 3 hours. After the addition was completed, the mixture was kept at 40°C for 1 hour, and a suitable amount of water was added to adjust the concentration of the reaction product to 50%. The pH of the reaction product is adjusted to 6.0-7.0 with sodium hydroxide to obtain a polycarboxylate water reducer; The acrylic acid aqueous solution is 10 g of acrylic acid solution dissolved in 30 g of water, the vitamin C aqueous solution is 0.6 g of vitamin C dissolved in 30 g of water, and the thioglycolic acid aqueous solution is 0.6 g of thioglycolic acid dissolved in 30 g of water. The molecular weight of ethylene glycol monovinyl polyethylene glycol ether is 3,000.

[0027] 2. The preparation process of modified cellulose ether is: 8 g of 32% sodium hydroxide solution was added to 100 g of carboxymethyl cellulose for alkaline treatment, the temperature was raised to 90°C, and 80 g of propylene oxide was added, and the reaction was carried out at 90°C for 3 hours to obtain modified cellulose ether.

[0028] Among them, the molecular weight of carboxymethyl cellulose is 90,000 and the degree of substitution is 0.7.

[0029] 3. The preparation process of high performance polycarboxylate water reducer is: 75 g of polycarboxylate water reducer was blended with 20 g of modified cellulose ether to obtain a high-performance polycarboxylate water reducer.

[0030] Comparative Example 1 (Compared with Example 1, the preparation process of the polycarboxylate water-reducing agent lacks the addition of hydrophobic monomer) 1. The preparation process of polycarboxylate water reducer is: 85g of ethylene glycol monovinyl polyglycol ether, 2g of hydrogen peroxide and 50g of water were added to a reaction kettle, the temperature was controlled at 40°C, and then vitamin C aqueous solution, acrylic acid aqueous solution and thioglycolic acid aqueous solution were added dropwise at a uniform speed for 3 hours. After the addition was completed, the mixture was kept at 40°C for 1 hour, and a suitable amount of water was added to adjust the concentration of the reaction product to 50%. The pH of the reaction product was adjusted to 6.0-7.0 with sodium hydroxide to obtain a polycarboxylic acid water reducer. The vitamin C aqueous solution is 0.7 g of vitamin C dissolved in 30 g of water, the thioglycolic acid aqueous solution is 0.5 g of thioglycolic acid dissolved in 30 g of water, and the acrylic acid aqueous solution is 15 g of acrylic acid dissolved in 30 g of water. The molecular weight of ethylene glycol monovinyl polyethylene glycol ether is 3,000.

[0031] 2. The preparation process of modified cellulose ether is: 8 g of 32% sodium hydroxide solution was added to 100 g of carboxymethyl cellulose for alkaline treatment, the temperature was raised to 60°C, and 20 g of propylene oxide was added, and the reaction was carried out at 60°C for 1 hour to obtain modified cellulose ether.

[0032] Among them, the molecular weight of carboxymethyl cellulose is 90,000 and the degree of substitution is 0.7.

[0033] 3. The preparation process of high performance polycarboxylate water reducer is: 75 g of polycarboxylate water reducer was blended with 20 g of modified cellulose ether to obtain a high-performance polycarboxylate water reducer.

[0034] Comparative Example 2 (Compared with Example 1, no modified cellulose ether was added) The difference between this comparative example and Example 1 is that the prepared high-performance polycarboxylate water-reducing agent contains only polycarboxylate water-reducing agent components, without the addition of modified cellulose ether.

[0035] The specific preparation process of polycarboxylate water reducer is: 30g of 2,2,3,3-tetrafluoropropyl methacrylate, 85g of ethylene glycol monovinyl polyethylene glycol ether, 2g of hydrogen peroxide and 50g of water were added to a reaction kettle, the temperature was controlled at 40°C, and then vitamin C aqueous solution, acrylic acid aqueous solution and thioglycolic acid aqueous solution were added dropwise at a uniform speed for 3h. After the addition was completed, the mixture was kept at 40°C for 1h, and a suitable amount of water was added to adjust the concentration of the reaction product to 50%. The pH of the reaction product was adjusted to 6.0-7.0 with sodium hydroxide to obtain a polycarboxylic acid water reducer. The vitamin C aqueous solution is 0.7 g of vitamin C dissolved in 30 g of water, the thioglycolic acid aqueous solution is 0.5 g of thioglycolic acid dissolved in 30 g of water, and the acrylic acid aqueous solution is 15 g of acrylic acid dissolved in 30 g of water.

[0036] Among them, the molecular weight of ethylene glycol monovinyl polyethylene glycol ether is 3000.

[0037] Comparative Example 3 (Existing water reducing agent) Kezhijie New Materials Group Co., Ltd. produces PS polycarboxylate water reducer.

[0038] Comparative Example 4 (the polymerizable monomer used is different from the hydrophobic monomer selected in the embodiment) The only difference from Example 1 is that the hydrophobic monomer allyl chloroformate is used in place of the hydrophobic monomer 2,2,3,3-tetrafluoropropyl methacrylate, and the other preparation processes and conditions are the same as those of Example 1.

[0039] Comparative Example 5 (the ratio of polycarboxylate water-reducing agent to modified cellulose ether is different from that in the example) The only difference from Example 1 is that 90 g of polycarboxylate water-reducing agent is blended with 10 g of modified cellulose ether, and the other preparation processes and conditions are the same as those in Example 1.

[0040] Performance tests of embodiments and comparative examples: The concrete mixture performance test was carried out in accordance with GB / T 50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures". The concrete mix ratio is: cement 360kg / m 3 、Mechanical sand 790kg / m 3 、Stone 1060kg / m 3 、Water 172kg / m 3 When the existing traditional polycarboxylate water reducer is used in this concrete formula, the concrete segregation and bleeding are serious.

[0041] The performance of the water reducing agent products prepared in the specific embodiments and comparative examples when applied to concrete is shown in Table 1 below: Table 1 sample Polycarboxylate water reducer dosage / % Initial slump / mm 2h slump / mm Water seepage rate / % Workability Example 1 0.15 225 215 0 Concrete has good cohesiveness and wrapping properties Example 2 0.15 220 210 0 Concrete has good cohesiveness and wrapping properties Example 3 0.15 225 215 0 Concrete has good cohesiveness and wrapping properties Comparative Example 1 0.15 215 155 1.5 Concrete has poor cohesion and wrapping properties Comparative Example 2 0.15 200 190 1.7 Concrete has poor cohesion and wrapping properties Comparative Example 3 0.15 210 140 8.2 Concrete has poor cohesion and encapsulation, and severe concrete segregation and bleeding Comparative Example 4 0.15 205 150 3.2 Concrete has poor cohesion and wrapping properties Comparative Example 5 0.15 200 185 2.3 Concrete has poor cohesion and wrapping properties Analysis of the above comparative examples and embodiment data shows that: Compared with Comparative Example 1 (compared with the example, the preparation process of the polycarboxylate water-reducing agent lacks the addition of hydrophobic monomers), the high-performance polycarboxylate water-reducing agent prepared in Examples 1-3 has good slump retention performance, no segregation and bleeding of concrete, and good cohesiveness and wrapping of concrete. The main reasons for this are: Since the polycarboxylate water-reducing agent in the embodiment has water-retaining and micro-air-entraining effects, a large number of fluorine groups and other groups on its molecular chain form hydrogen bonds with water molecules, forming a three-dimensional network structure inside the cement paste, which increases the viscosity of the mixture and reduces the free water. As the hydrogen bond binding force weakens, a large amount of free water is gradually released, so that the concrete mixture maintains good plasticity and improves the slump retention performance of the concrete. The micro-air-entraining effect of the high-performance polycarboxylate water-reducing agent improves the encapsulation of the concrete and reduces the water bleeding rate.

[0042] Compared with Comparative Example 2 (without modified cellulose ether), the high-performance polycarboxylate water-reducing agent prepared in Examples 1-3 has good thickening and water-retention performance, and the concrete water bleeding rate is low. The main reasons are analyzed as follows: Since the modified cellulose ether is adsorbed on the surface of cement particles, it delays the early hydration process of cement and significantly affects the evolution of the pore structure of fresh cement-based materials, thus playing a role in thickening and retaining water in concrete.

[0043] Compared with Comparative Example 3 (existing water reducer), the high-performance polycarboxylic acid water reducer prepared in Examples 1-3 has good slump retention performance, no segregation and water bleeding in the mixed concrete, and good concrete cohesion and encapsulation.

[0044] Compared with Comparative Example 4 (the polymerized monomer used is different from the hydrophobic monomer selected in the embodiment), the high-performance polycarboxylate water-reducing agent prepared in Examples 1-3 has good slump retention performance, there is no segregation and bleeding of concrete when mixed, and the concrete has good cohesiveness and encapsulation.

[0045] In addition, in addition to the polymerized monomer allyl chloroformate used in Comparative Example 4, if methyl 2-bromoprop-2-enoate or methyl methacrylate is used to replace the hydrophobic monomer specifically selected in the present application, the obtained water reducer is used in concrete, and the concrete has poor slump retention performance, poor workability, and high water bleeding rate.

[0046] Compared with Comparative Example 5 (the ratio of polycarboxylate water-reducing agent to modified cellulose ether is different from that in Example 1), the high-performance polycarboxylate water-reducing agent prepared in Examples 1-3 has good slump retention performance, there is no segregation and bleeding of concrete, and the concrete has good cohesion and encapsulation.

[0047] Therefore, in the embodiment of the present application, a high-performance polycarboxylate water-reducing agent is prepared by compounding a polycarboxylate water-reducing agent with a modified cellulose ether, and the polycarboxylate water-reducing agent is applied to concrete. The concrete has good initial fluidity, good slump retention performance, good water retention, encapsulation and cohesion, and there is no segregation and bleeding phenomenon in the mixed concrete.

[0048] In summary, the high-performance polycarboxylate water-reducing agent provided in this application has at least the following design concepts and beneficial effects: (1) Components of high-performance polycarboxylate water-reducing agent Polycarboxylate water-reducing agent has water-retaining and micro-air-entraining effects. A large number of fluorine and other groups on its molecular chain form hydrogen bonds with water molecules, forming a three-dimensional network structure inside the cement paste, which increases the viscosity of the mixture and reduces the free water. As the hydrogen bond force weakens, a large amount of free water is gradually released, allowing the concrete mixture to maintain good plasticity and improve the concrete's slump-retaining performance. The micro-air-entraining effect of high-performance polycarboxylate water-reducing agent improves the encapsulation of concrete and reduces the water bleeding rate.

[0049] (2) The modified cellulose ether component in the high-performance polycarboxylate water-reducing agent can be adsorbed on the surface of cement particles, thereby delaying the early hydration process of cement. At the same time, it significantly affects the evolution of the pore structure of fresh cement-based materials and plays a role in thickening and retaining water in concrete.

[0050] (3) The polycarboxylate water-reducing agent and modified cellulose ether are compounded to prepare a high-performance polycarboxylate water-reducing agent. When applied to concrete, the concrete has good initial fluidity and good slump retention performance. The concrete has good water retention, encapsulation and cohesion, and there is no segregation and bleeding in the mixed concrete. If the polycarboxylate water-reducing agent (formed by polymerization of vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer) is used alone in concrete, the water retention performance of the concrete is poor; if the modified cellulose ether is used alone in concrete, the initial dispersion performance and slump retention performance of the concrete are poor.

[0051] In summary, the high-performance polycarboxylate water-reducing agent of the present application is compounded by a polycarboxylate water-reducing agent and a modified cellulose ether in a specific ratio. When the composite water-reducing agent is applied to concrete, the concrete has good initial fluidity and good slump retention performance, and the concrete has good water retention, encapsulation and cohesion, and there is no segregation and bleeding phenomenon in the mixed concrete.

[0052] It should be noted that: Degree of substitution of carboxymethyl cellulose: the amount of substance that has been substituted on the active hydroxyl group of each D-glucose unit of cellulose.

[0053] In this article, “~” is used to indicate a numerical range, and the range indicated by this expression includes two endpoint values.

[0054] In addition to the actual selections embodied in the above specific embodiments, the above formulation ranges may be used in the specific implementation of the present application, including but not limited to the above embodiment schemes.

[0055] The specific parameters or some commonly used reagents or raw materials in the above embodiments are specific embodiments or preferred embodiments of the present application, but are not intended to limit the present application. Those skilled in the art may make adaptive adjustments within the scope of the present application.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high performance polycarboxylate water reducer, characterized in that: Its components include polycarboxylate water-reducing agent and modified cellulose ether; The polycarboxylate water reducer is prepared by polymerization reaction of vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer under the action of initiator and chain transfer agent; The functional monomer is 3-[tri(1-methylethoxy)silyl]propyl methacrylate or a hydrophobic monomer, and the hydrophobic monomer has the following structural formula: ， Wherein, a value is 1 or 2, b value is an integer from 1 to 7, R1 is H or CH3, and R2 is H or F.

2. The high performance polycarboxylate water reducer according to claim 1, characterized in that: The weight ratio of the polycarboxylate water-reducing agent to the modified cellulose ether is (60-80): (15-20).

3. The high performance polycarboxylate water reducer according to claim 1, characterized in that: The preparation process of the modified cellulose ether is as follows: adding alkali solution to cellulose for alkaline treatment; heating to 60-90° C., adding propylene oxide and reacting at 60-90° C. for 1-3 hours to obtain the modified cellulose ether; The weight ratio of the carboxymethyl cellulose, alkali solution and propylene oxide is 100: (5-20): (20-100), and the mass concentration of the alkali solution is (30-35)%.

4. The high performance polycarboxylate water reducer according to claim 3, characterized in that: The cellulose is carboxymethyl cellulose, with a molecular weight of 90,000 to 250,000 and a degree of substitution of 0.7 to 1.2; The alkali solution is sodium hydroxide solution.

5. The high performance polycarboxylate water reducer according to claim 1, characterized in that: Under the action of an initiator and a chain transfer agent, the vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer are polymerized to obtain a polycarboxylic acid water reducer; Wherein, the polymerization reaction temperature is 40-45°C; The weight ratio of the vinyl polyether macromonomer, the unsaturated carboxylic acid and the functional monomer is (80-100): (10-15): (10-30).

6. The high performance polycarboxylate water reducer according to claim 1, characterized in that: The initiator is composed of a reducing agent and an oxidizing agent; The polymerization process is: By weight, 10 to 30 parts of functional monomers, 80 to 100 parts of vinyl polyether macromonomers, 1 to 2 parts of oxidants and 50 to 80 parts of water are added into a reactor; Control the temperature of the reaction system at 40-45°C, then add 30.5-30.8 parts of reducing agent aqueous solution, 40-45 parts of unsaturated carboxylic acid aqueous solution, and 30.4-30.9 parts of chain transfer agent aqueous solution respectively, and the addition time is 3-4 hours; After the reducing agent aqueous solution, the unsaturated carboxylic acid aqueous solution and the chain transfer agent aqueous solution are added, the mixture is kept at 40 to 45° C. for 1 to 5 hours, and a suitable amount of water is added to adjust the concentration of the reaction product to 40 to 50%; The pH of the reaction product is adjusted to 6.0-7.0 with alkali to obtain a polycarboxylate water reducer; The unsaturated carboxylic acid aqueous solution is formed by dissolving 10 to 15 parts of unsaturated carboxylic acid in 30 parts of water; the reducing agent aqueous solution is formed by dissolving 0.5 to 0.8 parts of reducing agent in 30 parts of water; and the chain transfer agent aqueous solution is formed by dissolving 0.4 to 0.9 parts of chain transfer agent in 30 parts of water.

7. The high performance polycarboxylate water reducer according to claim 6, characterized in that: The reducing agent aqueous solution, the unsaturated carboxylic acid aqueous solution and the chain transfer agent aqueous solution are added dropwise.

8. The high performance polycarboxylate water reducer according to claim 1, characterized in that: The molecular weight of the vinyl polyether macromonomer is 2400 to 5000; The unsaturated carboxylic acid is acrylic acid.

9. The high performance polycarboxylate water reducer according to claim 6, characterized in that: The reducing agent is one or more combinations of bisulfite, sulfite, bleaching agent, and vitamin C; The oxidant is hydrogen peroxide; The chain transfer agent is one or more combinations of mercaptoethanol, thioglycolic acid, mercaptopropionic acid, n-dodecyl mercaptan, secondary dodecyl mercaptan, and tert-dodecyl mercaptan; The base is sodium hydroxide.

10. A method for preparing a high-performance polycarboxylate water-reducing agent according to any one of claims 1 to 9, characterized in that: The method comprises the following preparation steps: The high-performance polycarboxylate water-reducing agent is obtained by mixing the polycarboxylate water-reducing agent and the modified cellulose ether.

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