Preparation method of sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer

Abstract

The present application discloses a method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer, which relates to the technical field of building materials, including S100. preparing a mixed solution A containing PEGMA-SSBS monomer; S200. preparing a mixed solution B; S300. synthesizing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer PCE-B. The present application introduces sodium 3-carboxybenzenesulfonate containing -SO3- and -COOH groups and polymethacrylate to synthesize a modified monomer by free radical polymerization, and then synthesizes a modified polycarboxylic acid water reducer having a diester bond and sodium sulfonate with isopentanol polyoxyethylene ether and acrylic acid, so that the synthesized PCE-B has a promoting effect on the initial cement paste fluidity, and at the same time, the addition of the modified monomer PEGMA-SSBS significantly improves the adsorption capacity of PCE-B to cement particles.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid-based water reducer. Background Art

[0002] There are more and more projects completed and planned in high-altitude areas, but the complex climate environment has brought a series of technical difficulties. The requirements for admixtures in concrete construction are also getting higher and higher. Based on the many advantages of PCE such as low dosage, high water reduction rate, and green environmental protection, it has become the main hot direction for research on water reducers at home and abroad. However, in order to prepare high-strength concrete to improve the strength in the early stage of engineering construction, the synthesized modified PCE needs to improve the fluidity and adsorption properties of cement while having early strength function. The present application develops a method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer to solve the above problems. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer to solve one or more of the above-mentioned prior art problems.

[0004] The present application provides a method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer, comprising the following steps:

[0005] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, comprising, by weight: 20-50 parts of acrylic acid AA, 1-25 parts of PEGMA-SSBS, and 25-79 parts of distilled water;

[0006] S200. Prepare a mixed solution B, comprising, by mass, 1-5 parts of 3-mercaptopropionic acid MPA, 1-5 parts of L-ascorbic acid Vc, and 140-148 parts of distilled water;

[0007] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B: 300 parts by mass of distilled water were added to 250 parts by mass of isopentyl polyoxyethylene ether TPEG to dissolve it, and then 1-5 parts by mass of H 2 O 2， The concentration is 30% H 2 O 2 , further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B were added dropwise at the same time. After the addition of mixed solution A and mixed solution B was completed, the mixture was kept warm, freeze-dried, and ground to obtain a white powder C, which was sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0008] As a preferred embodiment that can be realized, step S100. The preparation method of PEGMA-SSBS specifically includes:

[0009] S101. 350-450 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of 3-carboxybenzenesulfonate sodium SSBS are placed in a flask, and then 1-3 parts by mass of 4-dimethylaminopyridine DMAP and 1-3 parts by mass of triethylamine TEA are added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0010] S102. Introduce argon atmosphere and react with stirring at room temperature. After the reaction is completed, remove excess reaction monomers by suction filtration, and then extract, rotary evaporate, and precipitate. After standing, suction filtration is performed again, freeze-drying, and grinding to obtain a relatively viscous colorless and transparent substance, namely the obtained PEGMA-SSBS monomer.

[0011] As a preferred embodiment that can be realized, saturated brine is used for extraction three times and then the lower layer solution is obtained by separation. Then, excess dichloromethane is removed by rotary evaporation, and precipitation is carried out with ether reagent to produce a white suspension. After standing at a temperature of -4°C overnight, it is filtered and freeze-dried to obtain a relatively viscous colorless transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0012] In a further preferred embodiment, the synthesis reaction formula of step S100 is as follows:

[0013] .

[0014] As a preferred embodiment that can be realized, step S300 synthesizes sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water into a flask, heating the isopentyl polyoxyethylene ether to dissolve it, and adding 1-5 parts by mass of H 2 O 2， H 2 O 2 The concentration is 30% H 2 O 2 , and further stir evenly, and at the same time, add 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B, the mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, keep warm for 1 hour, add sodium hydroxide aqueous solution to adjust the pH value of the solution to neutral, and then freeze-dry and grind to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0015] As a preferred embodiment that can be realized, the synthetic reaction formula prepared in step S300 is:

[0016] .

[0017] The beneficial effects of the present invention are:

[0018] The present application discloses a method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer. The present invention adopts SSBS to modify PEGMA to prepare a new modified monomer PEGMA-SSBA, and introduces it into a PCE synthesis system to prepare a new polycarboxylic acid water reducer (PCE-B) containing a diester bond and -SO3-, so that the synthesized PCE-B has a promoting effect on the initial pure paste fluidity of cement, and the addition of the modified monomer PEGMA-SSBS significantly improves the adsorption capacity of PCE-B to cement particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a test graph of the time-dependent fluidity of cement paste with polycarboxylate water-reducing agents of different mass fractions of PEGMA-SSBS modified monomers in the present invention when the water-reducing agent is added in an amount of 0.15%;

[0020] Figure 2 The figure shows the change trend of the fluidity of the polycarboxylate water-reducing agent cement paste with different mass fractions of PEGMA-SSBS modified monomers of the present invention over time. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail by examples below. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0023] It should be noted that PCE-B is formed by free radical polymerization of TPEG, AA, and PEGMA-SSBS. The following also provides examples corresponding to PCE-B-1%, PCE-B-3%, PCE-B-5%, and PCE-B-7%. The 1% in the example means that the mass of PEGMA-SSBS accounts for 1% of the mass of TPEG in S300. 3-Mercaptopropionic acid MPA is a chain transfer agent, and its usage ratio is the ratio of the mass of TPEG in S300; H2O2 is an initiator, and its usage ratio is the ratio of the mass of TPEG.

[0024] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 33.75 parts of acrylic acid AA, 2.5 parts of PEGMA-SSBS, and 63.75 parts of distilled water, and stir the above raw materials to mix them evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0025] S101. 350 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0026] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0027] S200. Prepare a mixed solution B, which includes, by weight: 1.25 parts of 3-mercaptopropionic acid MPA, 1.5 parts of L-ascorbic acid Vc, and 147.25 parts of distilled water, and mix and stir the above.

[0028] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 1.5 parts by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and it is further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0029] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 33.75 parts of acrylic acid AA, 7.5 parts of PEGMA-SSBS, and 58.75 parts of distilled water, and stir the above raw materials to mix evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0030] S101. 350 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0031] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0032] S200. Prepare a mixed solution B, which includes, by weight: 1.25 parts of 3-mercaptopropionic acid MPA, 1.5 parts of L-ascorbic acid Vc, and 147.25 parts of distilled water, and mix and stir the above.

[0033] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 1.5 parts by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and it is further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0034] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 33.75 parts of acrylic acid AA, 12.5 parts of PEGMA-SSBS, and 53.75 parts of distilled water; stir and mix the above raw materials evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0035] S101. 350 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0036] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0037] S200. Prepare a mixed solution B, which includes, by weight: 1.25 parts of 3-mercaptopropionic acid MPA, 1.5 parts of L-ascorbic acid Vc, and 147.25 parts of distilled water, and mix and stir the above.

[0038] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 1.5 parts by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and it is further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0039] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 33.75 parts of acrylic acid AA, 17.5 parts of PEGMA-SSBS, and 48.75 parts of distilled water; stir and mix the above raw materials evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0040] S101. 350 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0041] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0042] S200. Prepare a mixed solution B, which includes, by weight: 1.25 parts of 3-mercaptopropionic acid MPA, 1.5 parts of L-ascorbic acid Vc, and 147.25 parts of distilled water, and mix and stir the above.

[0043] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 1.5 parts by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and it is further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0044] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 20 parts of acrylic acid AA, 20 parts of PEGMA-SSBS, and 60 parts of distilled water; stir and mix the above raw materials evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0045] S101. 350 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0046] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0047] S200. Prepare a mixed solution B, which includes, by weight: 1 part of 3-mercaptopropionic acid MPA, 1 part of L-ascorbic acid Vc, and 148 parts of distilled water, and mix and stir the above.

[0048] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 1 part by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0049] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 50 parts of acrylic acid AA, 25 parts of PEGMA-SSBS, and 25 parts of distilled water; stir and mix the above raw materials evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0050] S101. 450 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0051] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0052] S200. Prepare a mixed solution B, which includes, by weight: 5 parts of 3-mercaptopropionic acid MPA, 5 parts of L-ascorbic acid Vc, and 140 parts of distilled water, and mix and stir the above.

[0053] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 5 parts by mass of H 2 O 2 , H 2 O 2The concentration is 30%, and further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0054] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 20 parts of acrylic acid AA, 1 part of PEGMA-SSBS, and 79 parts of distilled water; stir and mix the above raw materials evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0055] S101. 350 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0056] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0057] S200. Prepare a mixed solution B, which includes, by weight: 3 parts of 3-mercaptopropionic acid MPA, 3 parts of L-ascorbic acid Vc, and 144 parts of distilled water, and mix and stir the above.

[0058] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 3 parts by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0059] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 20 parts of acrylic acid AA, 10 parts of PEGMA-SSBS, and 70 parts of distilled water; stir and mix the above raw materials evenly; the specific preparation steps of PEGMA-SSBS are as follows:

[0060] S101. 450 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate SSBS were placed in a 100 ml round-bottom flask, and then 1 part by mass of 4-dimethylaminopyridine DMAP and 1 part by mass of triethylamine TEA were added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent;

[0061] S102. During the reaction in step 1, argon atmosphere is introduced and the reaction is stirred at room temperature. After the reaction is completed, excess reaction monomers are removed by filtration, and then the mixture is extracted, evaporated, and precipitated. After standing, filtration is performed again, freeze-dried, and ground to obtain a relatively viscous colorless and transparent substance, i.e., the obtained PEGMA-SSBS monomer.

[0062] S200. Prepare a mixed solution B, which includes, by weight: 3 parts of 3-mercaptopropionic acid MPA, 3 parts of L-ascorbic acid Vc, and 144 parts of distilled water, and mix and stir the above.

[0063] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 5 parts by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0064] Comparative Example 1 PCE-B is the same as Example 1, except that it does not contain PEGMA-SSBS monomer, and specifically comprises:

[0065] S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, which includes, by weight, 33.75 parts of acrylic acid AA and 63.75 parts of distilled water; stir and mix the above raw materials uniformly:

[0066] S200. Prepare a mixed solution B, which includes, by weight: 1.25 parts of 3-mercaptopropionic acid MPA, 1.5 parts of L-ascorbic acid Vc, and 147.25 parts of distilled water, and mix and stir the above.

[0067] S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water in a 100 ml round-bottom flask, heating the isopentyl polyoxyethylene ether to dissolve, and adding 1.5 parts by mass of H 2 O 2 , H 2 O 2 The concentration is 30%, and further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B are added dropwise at the same time. The mixed solution A is added dropwise within 3 hours, and the mixed solution B is added dropwise within 3.5 hours. After all the additions are completed, the mixture is kept warm for 1 hour, and a sodium hydroxide aqueous solution is added to adjust the pH value of the solution to neutral, and then freeze-dried and ground to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer.

[0068] As shown in Table 1 below, PCE-B prepared with different PEGMA-SSBS monomer mass fractions is provided.

[0069] Table 1

[0070] sample Monomer mass fraction (%) Initiator dosage (%) Chain transfer agent dosage (%) Temperature (℃) PCE 0 0.60 0.5 35 PCE-B-1% 1 0.60 0.5 35 PCE-B-3% 3 0.60 0.5 35 PCE-B-5% 5 0.60 0.5 35 PCE-B-7% 7 0.60 0.5 35

[0071] The PCE-B-1%, PCE-B-3%, PCE-B-5%, and PCE-B-7% prepared in Table 1 have corresponding examples provided above. The chain transfer agent in Table 1 is 3-mercaptopropionic acid MPA, and the initiator is H 2 O 2 The reaction temperature is 35°C. The molecular weight of acrylic acid in the present application is 72, and the molecular weight of TPEG is 2400. The amount of chain transfer agent is the ratio of its mass to the mass of isopentenyl polyoxyethylene ether TPEG in S300. The amount of initiator is the ratio of its mass to the mass of isopentenyl polyoxyethylene ether TPEG in S300.

[0072] Performance testing methods for this application:

[0073] Structural performance test characterization method: Nuclear magnetic resonance hydrogen spectrum (1H NMR): The chemical structure of the polymer was characterized by 1H NMR, and deuterated water was selected as the solvent.

[0074] As shown in the figure, the infrared characterization diagram of PCE-B modified with different dosages was obtained by the above method. PCE-B is formed by free radical polymerization of TPEG-2400, AA, and PEGMA-SSBS. As shown in the figure, the peaks at 3480, 2749, and 1654 cm-1 are the stretching vibration peaks of -OH at the end of the long side chain in the synthetic polymer molecule; the stretching vibration peak of the saturated CH bond in the molecule; and the stretching vibration of CO of the side chain, the carboxylic acid group of the polymer molecule; the stretching vibration peak of -SO3- is generated at 1190 cm-1, and the peak intensity increases with the increase of the dosage; the stretching vibration peak of benzenesulfonic acid is generated at 1210 cm-1, and the peak intensity increases with the increase of the dosage. This shows that the PEGMA-SAA designed in the experiment is indeed synthesized on PCE, and the 3-sodium carboxysulfonate modified polycarboxylic acid water reducer is synthesized.

[0075] The polycarboxylate water-reducing agent (PCE-B) with different mass fractions of PEGMA-SSBS modified monomer was tested for the initial cement paste fluidity with different mass fractions of water-reducing agent added and the time-dependent fluidity of cement paste with 0.15% water-reducing agent added. Figure 1 It can be seen that except for PCE-B-1%, which has an improved fluidity performance relative to PCE when the addition amount is 0.15%, the other mass fractions of PCE-B are all lower than the cement paste fluidity of PCE. However, with the increase of PCE-B addition, the cement paste fluidity of PCE-B-3%, PCE-B-5% and PCE-B-7% increased by 63.16%, 64.86% and 78.79% respectively. It can be seen that PCE-B will cause the cement paste fluidity to increase significantly with the increase of water reducer dosage. This is because -COO- in the monomer will decompose into -COOH in the alkaline environment of cement, and the PCE-B structure contains two ester bonds, which will have more -COOH, greatly increasing the carboxyl density and improving the adsorption of cement particles.

[0076] As time goes by, the fluidity of cement paste will also change after adding water reducer. This is because the minerals in cement undergo hydration reaction under the action of water to produce hydration products, which causes the cement to solidify and the fluidity of cement to decrease. Figure 2As time goes by, the fluidity of PCE cement paste shows a trend of first rising and then falling. PCE-B-1% and PCE-B-3% also show a trend of first rising and then falling. However, the fluidity of PCE-B-5% and PCE-B-7% cement paste has been in a downward trend as time goes by. After 2 hours, compared with the sample with PCE-B, the slump loss of PCE cement paste is 165 mm, and the slump losses of PCE-B-1%, PCE-B-3%, PCE-B-5% and PCE-B-7% cement paste are 110 mm, 150 mm, 120 mm and 100 mm respectively. It can be inferred that the water reducer PCE-B has a better maintaining effect on the slump of cement paste than the addition of PCE, and the slump retaining effect on cement paste is more obvious. This is because the structure of PCE-B contains -COO-, -SO3- and other groups. In the alkaline environment of cement, -COO- will decompose into -COOH to further adsorb cement particles, thereby slowing down the decline in cement fluidity. In summary, with the increase in the amount of PEGMA-SSBS monomer, PCE-B has an effect on improving the initial cement paste fluidity when the modified monomer content is 1%; and the other PCE-B samples have more effects on early strength and collapse retention of cement paste when the modified monomer content increases.

[0077] It will be clear to those skilled in the art that various modifications to the above embodiments may be made without departing from the overall spirit and concept of the present invention. All of these modifications fall within the scope of protection of the present invention. The protection scheme of the present invention shall be subject to the claims attached to the present invention.

Claims

1. A method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer, characterized in that: The following steps are involved: S100. Prepare a mixed solution A containing PEGMA-SSBS monomer, comprising, by weight: 20-50 parts of acrylic acid AA, 1-25 parts of PEGMA-SSBS, and 25-79 parts of distilled water; S200. Prepare a mixed solution B, comprising, by mass, 1-5 parts of 3-mercaptopropionic acid MPA, 1-5 parts of L-ascorbic acid Vc, and 140-148 parts of distilled water; S300. Synthesis of sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B: 300 parts by mass of distilled water were added to 250 parts by mass of isopentyl polyoxyethylene ether TPEG to dissolve it, and then 1-5 parts by mass of H2O 2， The concentration is 30% H2O2, further stirred evenly, and 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B were added dropwise at the same time. After the addition of mixed solution A and mixed solution B was completed, they were kept warm, freeze-dried, and ground to obtain white powder C, which was sodium carboxybenzenesulfonate modified polycarboxylate water reducer; Step S100. The preparation method of PEGMA-SSBS specifically comprises: S101. 350-450 parts by mass of poly(ethylene glycol) methacrylate PEGMA and 250 parts by mass of sodium 3-carboxybenzenesulfonate are placed in a flask, and then 1-3 parts by mass of 4-dimethylaminopyridine DMAP and 1-3 parts by mass of triethylamine TEA are added, followed by pouring 400-800 parts by mass of dichloromethane as a reaction solvent; S102. An argon atmosphere was introduced and the reaction was stirred at room temperature. After the reaction was completed, excess reaction monomers were removed by filtration, and then extracted, evaporated, and precipitated. After standing, the mixture was filtered, freeze-dried, and ground to obtain a relatively viscous colorless transparent substance, namely, the obtained PEGMA-SSBS monomer; Step S300 synthesizes sodium carboxybenzenesulfonate modified polycarboxylate water reducer PCE-B, comprising the following steps: adding 250 parts by mass of isopentanyl polyoxyethylene ether TPEG and 300 parts by mass of distilled water into a flask, heating to dissolve the isopentanyl polyoxyethylene ether, adding 1-5 parts by mass of H2O2 after dissolution, wherein the concentration of H2O2 is 30%, and further stirring evenly, while dripping 100 parts by mass of mixed solution A and 150 parts by mass of mixed solution B, wherein the mixed solution A is dripped within 3 hours, and the mixed solution B is dripped within 3.5 hours, and after all dripping is completed, the mixture is kept warm for 1 hour, an aqueous sodium hydroxide solution is added to adjust the pH value of the solution to neutral, and then freeze-drying and grinding are performed to obtain a white powder, i.e., sodium carboxybenzenesulfonate modified polycarboxylate water reducer.

2. The method for preparing a sodium carboxybenzenesulfonate modified polycarboxylic acid water reducer according to claim 1, characterized in that: The solution was extracted three times with saturated brine and separated to obtain the lower layer solution. Excess dichloromethane was then removed by rotary evaporation and precipitated with ether reagent to produce a white suspension. After standing at -4°C overnight, the suspension was filtered and freeze-dried to obtain a relatively viscous colorless transparent substance, i.e., the obtained PEGMA-SSBS monomer.

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