High-adaptability mud-blocking functional monomer, mud-blocking polycarboxylic acid water reducing agent and preparation method and application of high-adaptability mud-blocking functional monomer and mud-blocking polycarboxylic acid water reducing agent

Abstract

The invention provides a high-adaptability mud-resistant functional monomer, a mud-resistant polycarboxylate superplasticizer and a preparation method and application of the high-adaptability mud-resistant functional monomer and the mud-resistant polycarboxylate superplasticizer. The functional monomer takes tertiary amine acrylate as a raw material, the tertiary amine acrylate and halogenated acid are subjected to quaternization reaction to obtain a compound a, the compound a and chitosan are subjected to esterification reaction to obtain a compound b, and the compound b is subjected to esterification reaction to obtain the high-adaptability mud-resistant polycarboxylate superplasticizer. The compound b and phosphorus pentoxide are subjected to a phosphorylation reaction; and carrying out free radical copolymerization reaction on the mud-blocking functional monomer, an unsaturated polyether monomer and an unsaturated carboxylic acid monomer to synthesize the polycarboxylic acid water reducing agent containing quaternary ammonium salt cations and a phosphonate structure at the same time. The sensitivity of the polycarboxylic acid water reducing agent to the mud content is effectively reduced, the mud resistance of the polycarboxylic acid water reducing agent is improved, and the water reducing agent has the advantages of being low in mixing amount, high in water reducing rate, simple in preparation process, safe, environmentally friendly, long in mud resistance time, high in adaptability to various concrete materials and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete admixtures, and in particular to a highly adaptable mud-blocking functional monomer, a mud-blocking polycarboxylate water-reducing agent, and a preparation method and application thereof. Background Art

[0002] Concrete is the most widely used and consumed building material in modern times. Its broad market and promising prospects have driven concrete technology into a period of rapid development, with its application areas continuing to expand. The use of admixtures is a primary avenue for advancement in concrete technology. Water reducers, a chemical admixture that improves the fluidity of concrete, can also significantly enhance the overall performance of the product, including workability, density, strength, and durability, even at a low water-cement ratio. They are the most widely used and consumed admixture. Polycarboxylic acid water reducers, as water reducers, are favored by the market due to their low dosage, high water reduction rate, excellent fluidity retention, excellent cement compatibility, low levels of harmful components, excellent hardened concrete properties, and suitability for the formulation of high-performance concrete.

[0003] However, with the development of the market, the high-quality sand and gravel required for concrete has been almost exhausted. Therefore, people have to settle for the second best option of using sand and gravel with a higher mud content to mix concrete. As the use of sand and gravel with a high mud content gradually increases, technicians have found that the soil particles in sand and gravel have a larger specific surface area and are more likely to absorb polycarboxylic acid water reducers than cement, which reduces the amount of polycarboxylic acid water reducer adsorbed by cement molecules. Under the same dosage, the cement does not absorb enough polycarboxylic acid water reducer, resulting in uneven dispersion, which in turn affects the strength of concrete. Therefore, the amount of polycarboxylic acid water reducer added has to be increased.

[0004] In the prior art, two technical means are usually used to eliminate this effect. First, a sacrificial agent is added to the synthesized polycarboxylate water-reducing agent mother liquor to add a certain anti-mud sacrificial agent. The sacrificial agent is more easily adsorbed by soil particles. After adsorbing the sacrificial agent, the soil particles have a thicker adsorption layer, which reduces their adsorption capacity for the polycarboxylate water-reducing agent. As a result, the cement molecules can adsorb more polycarboxylate water-reducing agent, thereby improving its anti-mud performance. Second, during the synthesis process of the polycarboxylate water-reducing agent mother liquor, the polycarboxylic acid molecules are modified to improve the anti-mud performance.

[0005] Patent 202111031041.3 discloses an anti-mud functional monomer, an anti-mud type polycarboxylic acid water reducer, a preparation method and an application thereof, which belongs to the field of building material concrete admixtures. The anti-mud functional monomer is made of the following raw materials in parts by weight: 100-130 parts of unsaturated aromatic substances, 120-140 parts of unsaturated amines, and 1-2.5 parts of silane coupling agents; the unsaturated aromatic substance is at least one of benzyl acrylate and OPPEA, and the unsaturated amines are allylamine and 5-amino Levulinic acid, wherein the weight ratio of allylamine to 5-aminolevulinic acid is (3-12):1; the anti-mud functional monomer of the present invention can effectively improve the anti-mud and slump-retaining properties of the polycarboxylate water-reducer; by introducing unsaturated aromatic substances benzyl acrylate and OPPEA to increase the steric hindrance of the side chain of the polycarboxylate water-reducer, a protective layer is formed on the soil surface and in the interlayer by the unsaturated amine; the two work together to prevent the side chain of the polycarboxylate water-reducer from being inserted into the soil, thereby improving the anti-mud and slump-retaining properties of the polycarboxylate water-reducer.

[0006] Patent CN103897116A discloses a mud-resistant polycarboxylate water reducer and its preparation method. The compound is polymerized using vinyl polyoxyethylene ether, sodium styrene sulfonate, acrylic acid, and acrylamide compounds as monomers under a redox initiation system. This invention utilizes the highly active vinyl polyoxyethylene ether as a macromonomer, resulting in a high reaction conversion rate and a high water reduction rate. However, the molecular structure is comb-like, and the side chains easily enter the clay framework, resulting in excessive water reducer dosage. Summary of the Invention

[0007] In view of the above-mentioned series of problems in the prior art, the soil particles in sand and gravel have a large specific surface area and are more likely to adsorb polycarboxylic acid water-reducing agents, which reduces the amount of polycarboxylic acid water-reducing agents adsorbed by cement molecules, thereby affecting the dispersibility and concrete strength. This application proposes a highly adaptable mud-blocking functional monomer, a mud-blocking polycarboxylic acid water-reducing agent, and a preparation method and application thereof. The mud-blocking functional monomer is subjected to a free radical copolymerization reaction with an unsaturated polyether monomer and an unsaturated carboxylic acid monomer to synthesize a polycarboxylic acid water-reducing agent containing both a quaternary ammonium salt cation and a phosphonate structure; the sensitivity of the polycarboxylic acid water-reducing agent to mud content is effectively reduced, and the mud-blocking performance of the polycarboxylic acid water-reducing agent is improved.

[0008] A highly adaptable mud-blocking functional monomer, wherein the functional monomer is prepared by reacting a tertiary amine acrylate with a halogenated acid to obtain a compound a, which is then esterified with chitosan to obtain a compound b, which is then phosphorylated with phosphorus pentoxide to obtain the compound b;

[0009] The molar ratio of the tertiary amine acrylate to the halogenated acid is 1:(1-1.1);

[0010] The molar ratio of the compound a to chitosan is 1:(1-1.1);

[0011] The molar ratio of the compound b to phosphorus pentoxide is 1:(1-1.1);

[0012] The tertiary amine acrylate is any one of dimethylaminoethyl acrylate, 3-(dimethylamino)propyl acrylate, or 3-(dimethylamino)butyl acrylate; the halogenated acid is any one of bromopropionic acid, bromobutyric acid, chloropropionic acid, and chlorobutyric acid.

[0013] Chitosan contains a large number of hydrophobic groups such as amino, ester, and hydroxyl groups, which further enhance the viscosity and water reduction effects, increase the structural skeleton, and enhance the anti-mud effect.

[0014] A method for preparing a highly adaptable mud-blocking functional monomer comprises the following steps: (1) reacting a tertiary amine acrylate and a halogenated acid at 45-75° C. for 4-8 hours, cooling to room temperature, removing the solvent by distillation under reduced pressure, washing, filtering, and drying to obtain a small monomer compound a containing a carboxyl group-containing quaternary ammonium salt cation; (2) placing compound a and 1,2-dichloroethane in a three-necked flask, introducing hydrogen chloride (purity 99.99%) gas, and reacting at room temperature for 0.5-4 hours; then adding chitosan and slowly introducing hydrogen chloride; heating to reflux at 45 The azeotrope of dichloroethane and water was evaporated at 83°C, separated into layers in a water separator, and the lower layer of 1,2-dichloroethane was added back into the reaction system. After reacting for 4 to 8 hours, the mixture was cooled to -15°C and filtered. The filter cake was recrystallized with methanol to obtain compound b containing chitosan and quaternary ammonium salt cations; (3) Compound b was added to methanesulfonic acid, and then phosphorus pentoxide was added at 0 to 5°C. The mixture was mechanically stirred and reacted for 2 to 4 hours under a nitrogen environment. After the reaction was completed, the product was precipitated with ether, and then washed, filtered, and dried to obtain a functional monomer.

[0015] The preparation method of the highly adaptable mud-blocking functional monomer specifically comprises the following steps: (1) adding a certain amount of anhydrous ethanol to a three-necked flask equipped with a reflux condenser and a stirrer, carrying out a quaternization reaction on tertiary amine acrylate and halogenated acid in a certain proportion, reacting at 45-75° C. for 4-8 hours, cooling to room temperature, removing the solvent by reduced pressure distillation at 60° C., then washing the mixture with ethyl acetate and acetone three times, filtering, and vacuum drying at 45° C. to obtain a small monomer compound a containing a quaternary ammonium salt cation of a carboxyl group; (2) putting the compound a synthesized in step (1) and 1,2-dichloroethane into a three-necked flask, introducing hydrogen chloride (purity 99.99%) gas, and reacting at room temperature for 0.5-4 hours; then adding chitosan to the above reaction mixture, and continuing to slowly Slowly introduce hydrogen chloride; raise the temperature to reflux, evaporate the azeotrope of dichloroethane and water at 45-83°C, separate the layers in a water separator, re-introduce the lower layer of 1,2-dichloroethane into the reaction system, react for 4-8 hours, cool to -15°C, filter, and recrystallize the filter cake with methanol to obtain compound b containing chitosan and quaternary ammonium salt cations; (3) add b synthesized in step (2) to methanesulfonic acid, and then add phosphorus pentoxide under reaction conditions of 0-5°C, mechanically stir the reaction under nitrogen environment for 2-4 hours, and after the reaction is completed, precipitate the product with ether, and then wash with acetone, methanol, and ether respectively, filter, and vacuum dry at 60-80°C for 12-24 hours to obtain compound c containing quaternary ammonium salt cations and phosphate groups.

[0016] A mud-blocking polycarboxylate water-reducing agent, comprising the highly adaptable mud-blocking functional monomer described above.

[0017] Preferably, the water reducer is obtained by free radical polymerization of a functional monomer, an unsaturated polyether monomer, and an unsaturated carboxylic acid monomer in the presence of an initiator and a chain transfer agent; the molar ratio of the unsaturated polyether monomer, the functional monomer, and the unsaturated carboxylic acid monomer is 1:(1-5.6):(1-7.2).

[0018] The unsaturated polyether monomer is any one of allyl polyoxyethylene ether, methallyl polyoxyethylene ether, isobutyl polyoxyethylene ether or isopentenyl polyoxyethylene ether, or a mixture of two or more in any proportion, and the molecular weight of the unsaturated polyether is between 1000 and 5000; the unsaturated carboxylic acid monomer is any one of acrylic acid, methacrylic acid, acryloyl chloride, methacryloyl chloride, maleic acid, maleic anhydride, itaconic acid and itaconic anhydride.

[0019] The above-mentioned initiator is a conventional free radical water-soluble initiator, and the amount used is 0.5%-5.0% of the total weight of the unsaturated polyether monomer, functional monomer, and unsaturated carboxylic acid monomer; preferably, the initiator can be selected from one or more of water-soluble hydrogen peroxide, ammonium persulfate, sodium persulfate, and potassium persulfate.

[0020] The chain transfer agent is any one of mercaptoethanol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, isopropyl alcohol, hypophosphorous acid, sodium hypophosphite, and potassium hypophosphite, or a mixture of two or more of them in any proportion, and the amount used is 0.5%-5.0% of the total weight of the unsaturated polyether monomer, functional monomer, and unsaturated carboxylic acid monomer.

[0021] A method for preparing a sludge-blocking polycarboxylate water-reducing agent comprises the following steps: adding an unsaturated polyether monomer and water into a reaction vessel, maintaining the temperature at 30-50°C, stirring for 20-60 minutes, sequentially adding a functional monomer, an unsaturated carboxylic acid monomer, an initiator, and a chain transfer agent into the reaction vessel, continuing to heat the reaction vessel, and reacting at 40-80°C for 2-10 hours; after the reaction is completed, neutralizing the reaction with an alkaline solution having a mass fraction of 20%-75%, and cooling the reaction mixture to room temperature to obtain the sludge-blocking polycarboxylate water-reducing agent.

[0022] The specific preparation method of the sludge-blocking polycarboxylate water reducer comprises the following steps: adding unsaturated polyether and water to a reaction container, keeping the temperature at 30-50° C., stirring for 20-60 minutes, sequentially adding compound C containing a phosphate group and a quaternary ammonium salt cation obtained in step (3), an unsaturated carboxylic acid and its derivatives, an initiator, and a chain transfer agent to the reaction container, continuing to heat, and conducting a polymerization reaction at 40-80° C. for 2-10 hours; after the reaction is completed, neutralizing with an alkaline solution with a mass fraction of 20%-75% to a pH value of 6.0-8.0, and cooling to room temperature to obtain a water reducer containing a quaternary ammonium salt cation and a phosphate group.

[0023] In order to improve the monomer conversion rate and copolymerization activity, the aqueous solution of carboxylic acid and its derivatives, compounds containing phosphoric acid and quaternary ammonium salt cations, initiator and chain transfer agent are added to the reaction container in a dropwise manner after the reaction starts, and the dropwise addition time is controlled within 1-4 hours.

[0024] The alkaline solution is an aqueous solution of a positive monovalent or positive divalent metal hydroxide or a carbonate thereof commonly used in experiments.

[0025] The pH value of the above-mentioned mud-blocking polycarboxylate water-reducing agent is 6.0-8.0, and the solid content is 35%-50%.

[0026] When used as an admixture for cement-based materials, the polycarboxylate water-reducing agent of the present invention has a dosage (solid content) of 0.05% to 0.17% of the mass of the cementitious material. This water-reducing agent containing quaternary ammonium salt cations and a phosphoric acid structure can be used alone or in combination with other commercially available water-reducing agents.

[0027] In the method for preparing the water reducer containing quaternary ammonium salt cations and a phosphate structure of the present invention, a polycarboxylate water reducer containing both quaternary ammonium salt cations and a phosphonate structure is synthesized by polymer structure design through free radical copolymerization of different compounds containing quaternary ammonium salt cations and a phosphate structure with polyether, unsaturated carboxylic acid and its derivatives.

[0028] Compared with the prior art, this application has the following advantages:

[0029] (1) The present invention introduces a phosphate group, which can synergistically act with the carboxylate group in the polyether monomer structure to greatly improve the competitive adsorption capacity for SO42- in cement, effectively improve the adsorption capacity for cement particles, and improve the adaptability and sensitivity of the polycarboxylate water reducer, thereby enhancing the mud resistance performance;

[0030] (2) The present invention introduces quaternary ammonium salt cationic monomers and unsaturated acid groups into the molecular structure of polycarboxylate water reducer, which interacts with phosphoric acid groups, carboxylic acid groups, etc., and has a greater steric hindrance and structural anti-intercalation effect, thereby enhancing the adsorption and dispersion properties and mud resistance of the polycarboxylate water reducer;

[0031] (3) The water-reducing agent obtained in this application has the advantages of low dosage, high water-reducing rate, simple preparation process, safety and environmental protection, long anti-mud time, and strong adaptability to various concrete materials;

[0032] (4) Chitosan contains a large number of hydrophobic groups such as amino, ester, and hydroxyl groups, which improve the viscosity reduction effect. The use of a structure with a smaller molecular weight makes the polycarboxylic acid molecules have better stretchability. The polycarboxylic acid molecules with short side chains form a thinner water layer in the concrete, thereby releasing more free water to reduce the viscosity of the concrete. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] In the examples of the present invention, the molecular weight of the polyether and the molecular weight and molecular weight distribution of the multifunctional water-reducing agent were determined using a Wyatt Technology Corporation gel permeation chromatography instrument. The gel column was a Shodex SB806 + 803 column connected in series; the eluent was tetrahydrofuran; the mobile phase speed was 1 ml / min; the injection volume was 20 μl; the sample preparation concentration was 0.5% (g sample / g mobile phase); the detector was a Shodex RI-71 differential refractive index detector; and the standard was a polyethylene glycol GPC standard (Sigma-Aldrich, molecular weights 1,010,000, 478,000, 263,000, 118,000, 44,700, 18,600, 6,690, 1,960, 628, and 232).

[0035] Example 1

[0036] (1) Preparation of small monomer a containing quaternary ammonium salt cations: A certain amount of anhydrous ethanol was added to a three-necked flask equipped with a reflux condenser and a stirrer, and 157.5 g (1.1 mol) of dimethylaminoethyl acrylate and 307.47 g (2.01 mol) of bromopropionic acid were subjected to quaternization reaction. The reaction was carried out at 45° C. for 4 h, then cooled to room temperature, and the solvent was removed by reduced pressure distillation at 60° C., and then washed three times with ethyl acetate and acetone, filtered, and dried in vacuo at 45° C. to obtain small monomer a.

[0037] (2) Preparation of compound b containing quaternary ammonium salt cation and chitosan structure: 106.6 g (0.36 mol) of the small monomer a synthesized in step (1) and 1,2-dichloroethane were put into a three-necked flask, hydrogen chloride (purity 99.99%) gas was introduced, and the reaction was carried out at room temperature for 0.5 h; then 116.1 g (0.72 mol) of chitosan was added to the above reaction mixture, and hydrogen chloride was continued to be slowly introduced; the temperature was raised to reflux, and the azeotrope of dichloroethane and water was evaporated at 45°C, and the layers were separated in a water separator, and the lower layer of 1,2-dichloroethane was re-introduced into the reaction system, the reaction was completed for 4 h, and the mixture was cooled to -15°C, filtered, and the filter cake was recrystallized with methanol to obtain compound b.

[0038] (3) Preparation of compound c containing a quaternary ammonium salt cation and a phosphate group: 155.23 g (0.26 mol) of compound b synthesized in step (2) was added to 6-12 ml of methanesulfonic acid, and then 42.58 g (0.3 mol) of phosphorus pentoxide was added at 5°C. The mixture was mechanically stirred for 4 h under a nitrogen atmosphere. After the reaction, the product was precipitated with ether, washed with acetone, methanol, and ether, respectively, filtered, and dried in vacuo at 70°C for 24 h to obtain compound c.

[0039] (4) Preparation of a water reducer containing a quaternary ammonium salt cation and a phosphate group: 200 g (0.1 mol) of methyl allyl polyoxyethylene ether (molecular weight 2000) and water were added to a reaction vessel, kept warm at 30°C, and stirred for 20 min. Compound c 71.65 g (0.12 mol), acrylic acid 10.1 g (0.14 mol), ammonium persulfate (0.96 g) and mercaptoethanol (1.2 g) were added to the reaction vessel in sequence, and the temperature was continued to rise. A polymerization reaction was carried out at 40°C for 2 h. After the reaction was completed, the mixture was neutralized with a 20% alkaline solution to a pH value of 6.0-8.0. After cooling to room temperature, a water reducer containing a quaternary ammonium salt cation and a phosphate group structure was obtained, which was designated as SV-1 with a molecular weight of 16890.

[0040] Example 2

[0041] (1) Preparation of small monomer a containing quaternary ammonium salt cations: A certain amount of anhydrous ethanol was added to a three-necked flask equipped with a reflux condenser and a stirrer, and 172.9 g (1.1 mol) of 3-(dimethylamino)propyl acrylate and 335.7 g (2.01 mol) of bromobutyric acid were subjected to quaternization reaction. The reaction was carried out at 45°C for 4 hours, then cooled to room temperature, and the solvent was removed by reduced pressure distillation at 60°C. The product was then washed three times with ethyl acetate and acetone, filtered, and dried in vacuo at 45°C to obtain small monomer a.

[0042] (2) Preparation of compound b containing quaternary ammonium salt cation and chitosan structure: 116.7 g (0.36 mol) of the small monomer a synthesized in step (1) and 1,2-dichloroethane were put into a three-necked flask, hydrogen chloride (purity 99.99%) gas was introduced, and the reaction was carried out at room temperature for 0.5 h; then 116.1 g (0.72 mol) of chitosan was added to the above reaction mixture, and hydrogen chloride was continued to be slowly introduced; the temperature was raised to reflux, and the azeotrope of dichloroethane and water was evaporated at 45°C, and the layers were separated in a water separator, and the lower layer of 1,2-dichloroethane was re-introduced into the reaction system, the reaction was completed for 4 h, and the mixture was cooled to -15°C, filtered, and the filter cake was recrystallized with methanol to obtain compound b.

[0043] (3) Preparation of compound c containing a quaternary ammonium salt cation and a phosphate group: 100.9 g (0.21 mol) of compound b synthesized in step (2) was added to 6-12 ml of methanesulfonic acid, and then 42.58 g (0.3 mol) of phosphorus pentoxide was added at 5°C. The mixture was mechanically stirred for 4 h under a nitrogen atmosphere. After the reaction, the product was precipitated with ether, and then washed with acetone, methanol, and ether, respectively, filtered, and dried in vacuo at 70°C for 24 h to obtain compound c.

[0044] (4) Preparation of a water reducer containing a quaternary ammonium salt cation and a phosphate group: 200 g (0.1 mol) of methyl allyl polyoxyethylene ether (molecular weight 2000) and water were added to a reaction vessel, kept warm at 30°C, and stirred for 20 min. 125.38 g (0.21 mol) of compound c, 10.1 g (0.14 mol) of acrylic acid, ammonium persulfate (0.96 g) and mercaptoethanol (1.2 g) were added to the reaction vessel in sequence. The temperature was continued to rise, and a polymerization reaction was carried out at 40°C for 2 h. After the reaction was completed, the mixture was neutralized with a 20% alkaline solution to a pH value of 6.0-8.0. After cooling to room temperature, a water reducer containing a quaternary ammonium salt cation and a phosphate group structure was obtained, which was designated as SV-2 with a molecular weight of 17890.

[0045] Example 3

[0046] (1) Preparation of small monomer a containing quaternary ammonium salt cations: A certain amount of anhydrous ethanol was added to a three-necked flask equipped with a reflux condenser and a stirrer, and 181.5 g (1.06 mol) of 3-(dimethylamino)butyl acrylate and 229.0 g (2.11 mol) of chloropropionic acid were subjected to a quaternization reaction in a certain proportion. The reaction was carried out at 45° C. for 4 h, then cooled to room temperature, and the solvent was removed by reduced pressure distillation at 60° C., and then washed three times with ethyl acetate and acetone, filtered, and dried in vacuo at 45° C. to obtain small monomer a.

[0047] (2) Preparation of compound b containing quaternary ammonium salt cation and chitosan structure: 167.84 g (0.6 mol) of the small monomer a synthesized in step (1) and 1,2-dichloroethane were put into a three-necked flask, hydrogen chloride (purity 99.99%) gas was introduced, and the reaction was carried out at room temperature for 0.5 h; then 145.08 g (0.9 mol) of chitosan was added to the above reaction mixture, and hydrogen chloride was continued to be slowly introduced; the temperature was raised to reflux, and the azeotrope of dichloroethane and water was evaporated at 45°C, and the layers were separated in a water separator, and the lower layer of 1,2-dichloroethane was re-introduced into the reaction system, the reaction was completed for 4 h, and the mixture was cooled to -15°C, filtered, and the filter cake was recrystallized with methanol to obtain compound b.

[0048] (3) Preparation of compound c containing a quaternary ammonium salt cation and a phosphate group: 273.99 g (0.65 mol) of compound b synthesized in step (2) was added to 6-12 ml of methanesulfonic acid, and then 127.75 g (0.9 mol) of phosphorus pentoxide was added at 5°C. The mixture was mechanically stirred under a nitrogen atmosphere for 4 h. After the reaction, the product was precipitated with ether, and then washed with acetone, methanol, and ether, respectively, filtered, and dried in vacuo at 70°C for 12-24 h to obtain compound c.

[0049] (4) Preparation of a water reducer containing a quaternary ammonium salt cation and a phosphate group: 200 g (0.1 mol) of methyl allyl polyoxyethylene ether (molecular weight 2000) and water were added to a reaction vessel, the temperature was kept at 30°C, and the mixture was stirred for 20 min. 238.82 g (0.4 mol) of compound c containing a phosphate group and a quaternary ammonium salt cation, 10.1 g (0.14 mol) of acrylic acid, ammonium persulfate (0.96 g) and mercaptoethanol (1.2 g) were added to the reaction vessel in sequence. The temperature was continued to rise, and a polymerization reaction was carried out at 40°C for 2 h. After the reaction was completed, the mixture was neutralized with a 20% alkaline solution to a pH value of 6.0-8.0. After cooling to room temperature, a water reducer containing a quaternary ammonium salt cation and a phosphate structure was obtained, which was designated as SV-3 and had a molecular weight of 18880.

[0050] Example 4

[0051] (1) Preparation of small monomer a containing quaternary ammonium salt cations: A certain amount of anhydrous ethanol was added to a three-necked flask equipped with a reflux condenser and a stirrer, and 186.1 g (1.3 mol) of dimethylaminoethyl acrylate and 379.9 g (3.1 mol) of chlorobutyric acid were subjected to quaternization reaction. The reaction was carried out at 45°C for 4 hours, then cooled to room temperature, and the solvent was removed by reduced pressure distillation at 60°C. The product was then washed three times with ethyl acetate and acetone, filtered, and dried in vacuo at 45°C to obtain small monomer a.

[0052] (2) Preparation of compound b containing quaternary ammonium salt cation and chitosan structure: 199.3 g (0.75 mol) of the small monomer a synthesized in step (1) and 1,2-dichloroethane were put into a three-necked flask, hydrogen chloride (purity 99.99%) gas was introduced, and the reaction was carried out at room temperature for 0.5 h; then 141.9 g (0.88 mol) of chitosan was added to the above reaction mixture, and hydrogen chloride was continued to be slowly introduced; the temperature was raised to reflux, and the azeotrope of dichloroethane and water was evaporated at 45°C, and the layers were separated in a water separator, and the lower layer of 1,2-dichloroethane was re-introduced into the reaction system, the reaction was completed for 4 h, and the mixture was cooled to -15°C, filtered, and the filter cake was recrystallized with methanol to obtain compound b.

[0053] (3) Preparation of compound c containing a quaternary ammonium salt cation and a phosphate group: 16.15 g (0.75 mol) of compound b3 synthesized in step (2) was added to 6-12 ml of methanesulfonic acid, and then 141.94 g (1.0 mol) of phosphorus pentoxide was added at 5°C. The mixture was mechanically stirred under a nitrogen atmosphere for 4 h. After the reaction, the product was precipitated with ether, and then washed with acetone, methanol, and ether, respectively, filtered, and dried in vacuo at 60°C for 24 h to obtain compound c.

[0054] (4) Preparation of a water reducer containing quaternary ammonium salt cations and phosphate groups: 200 g (0.1 mol) of methyl allyl polyoxyethylene ether (molecular weight 2000) and water were added to a reaction vessel, kept warm at 30°C, and stirred for 20 min. Compound c 298.53 g (0.5 mol), acrylic acid 10.1 g (0.14 mol), ammonium persulfate (0.96 g) and mercaptoethanol (1.2 g) were added to the reaction vessel in sequence. The temperature was continued to rise, and a polymerization reaction was carried out at 40°C for 2 h. After the reaction was completed, the mixture was neutralized with a 20% alkaline solution to a pH value of 6.0-8.0. After cooling to room temperature, a water reducer containing quaternary ammonium salt cations and phosphate structures was obtained, which was designated as SV-4 with a molecular weight of 13457.

[0055] Example 5

[0056] (1) Preparation of small monomer a containing quaternary ammonium salt cations: A certain amount of anhydrous ethanol was added to a three-necked flask equipped with a reflux condenser and a stirrer, and 193.3 g (1.35 mol) of dimethylaminoethyl acrylate and 417.5 g (2.5 mol) of bromobutyric acid were subjected to quaternization reaction. The reaction was carried out at 45° C. for 4 h, then cooled to room temperature, and the solvent was removed by reduced pressure distillation at 60° C., and then washed three times with ethyl acetate and acetone, filtered, and dried in vacuo at 45° C. to obtain small monomer a.

[0057] (2) Preparation of compound b containing quaternary ammonium salt cation and chitosan structure: 198.5g (0.64mol) of the small monomer a synthesized in step (1) and 1,2-dichloroethane were placed in a three-necked flask, hydrogen chloride (purity 99.99%) gas was introduced, and the reaction was carried out at room temperature for 0.5h; then 161.2g (1mol) of chitosan was added to the above reaction mixture, and hydrogen chloride was continued to be slowly introduced; the temperature was raised to reflux, and the azeotrope of dichloroethane and water was evaporated at 45°C, and the layers were separated in a water separator, and the lower layer of 1,2-dichloroethane was re-added to the reaction system, and the reaction was completed for 4h. The mixture was cooled to -15°C, filtered, and the filter cake was recrystallized with methanol to obtain compound b.

[0058] (3) Preparation of compound c containing a quaternary ammonium salt cation and a phosphate group: 155.97 g (0.37 mol) of compound b synthesized in step (2) was added to 6-12 ml of methanesulfonic acid, and then 92.26 g (0.65 mol) of phosphorus pentoxide was added at 5°C. The mixture was mechanically stirred for 4 h under a nitrogen atmosphere. After the reaction, the product was precipitated with ether, washed with acetone, methanol, and ether, respectively, filtered, and dried in vacuo at 80°C for 24 h to obtain compound c.

[0059] (4) Preparation of a water reducer containing a quaternary ammonium salt cation and a phosphate group: 200 g (0.1 mol) of methyl allyl polyoxyethylene ether (molecular weight 2000) and water were added to a reaction vessel, kept warm at 30°C, and stirred for 20 min. 155.23 g (0.26 mol) of compound c, 10.1 g (0.14 mol) of acrylic acid, ammonium persulfate (0.96 g) and mercaptoethanol (1.2 g) were added to the reaction vessel in sequence. The temperature was continued to rise, and a polymerization reaction was carried out at 40°C for 2 h. After the reaction was completed, the mixture was neutralized with a 20% alkaline solution to a pH value of 6.0-8.0. After cooling to room temperature, a water reducer containing a quaternary ammonium salt cation and a phosphate structure was obtained, which was designated as SV-5 and had a molecular weight of 19457.

[0060] Test example:

[0061] In the application examples of the present invention, unless otherwise specified, the cement used is standard cement (P.042.5), the sand is medium sand with a fineness modulus Mx = 2.6, and the gravel is continuously graded crushed stone with a particle size of 5 to 20 mm. The cement paste fluidity test is carried out in accordance with the relevant provisions of GB8076-2018 "Concrete Admixtures" and the water reduction rate test method is carried out in accordance with the relevant provisions of JC473-2016 "Concrete Pumping Agents."

[0062] To further illustrate the performance of the highly adaptable polycarboxylate water-reducing agent with mud-blocking properties provided by the present invention, commercially available conventional comb-type polycarboxylate water-reducing agents (HX-YZJ01 from Wuhan Huaxuan High-Tech Co., Ltd. in Comparative Example 1 and D-JSJ2 from Guangzhou Dashengshi Building Materials Co., Ltd. in Comparative Example 2) were used as comparative samples. SV-1-5, HX-YZJ01, and D-JSJ2 were added to concrete and weighed with sand, gravel, cement, and water according to the mix proportions in Table 1.

[0063] Table 1

[0064] Helin cement / g Coal ash / g Mineral powder / g Sand / g Dashi / g Medium stone / g Small stone / g Water / g 250 70 70 740 500 460 340 160

[0065] Bentonite (produced by Lingshou County Hongrun Mineral Products Processing Plant) was used to replace the corresponding mass of cement by internal mixing. The bentonite content was 4% and the water reducer content was 0.18% (solidified). The mixture was added to a concrete mixer and stirred thoroughly. After the concrete was poured out, the slump cone was inverted, the bottom was sealed, and the cone was quickly filled with concrete and smoothed with a tool. The bottom cover was quickly slid open. A stopwatch was used to start timing. The time it took for the concrete to flow out was recorded as the backflow time of the concrete. The slump of the polycarboxylate water reducer was tested in accordance with GB / 8076-2022. The test results are shown in Table 2:

[0066] Table 2

[0067]

[0068] As shown in Table 2, the polycarboxylate water-reducing agent containing quaternary ammonium salt cations and a phosphoric acid structure according to the present invention has better water-reducing and slump-retaining performance under the same bentonite dosage conditions, indicating that it has better mud resistance; judging from the initial slump time of the slump bucket, the viscosity of the concrete is also significantly reduced.

[0069] Performance tests were conducted on the above embodiments and comparative examples to test the effects of the admixtures on the workability, consistency, 24h consistency, and compressive strength of M10 concrete after mixing with 20 kg of waste slurry water and different methylene blue values (hereinafter referred to as MB value, which is an overall indicator for determining whether there is expansive clay mineral (mud powder) in the machine-made sand and determining its content).

[0070] M10 concrete is made by mixing cement, fly ash, machine-made sand, tap water, waste slurry water, and the anti-mud wet-mix mortar admixtures in each embodiment and comparative example.

[0071] Cement: Conch PO42.5, dosage 170kg;

[0072] Fly ash: Second grade fly ash; loss on ignition 6.7%, dosage 30kg;

[0073] River sand: fineness modulus 1.9, MB value 0.4, dosage 1100kg;

[0074] Machine-made sand: fineness modulus 2.0, MB value 1.5, dosage 300kg;

[0075] Anti-mud wet-mix mortar admixture: dosage 3-4kg;

[0076] Tap water: 180kg;

[0077] Waste slurry: 50 kg, solid content of waste slurry: 10%. The test results are shown in Table 3 below:

[0078] Table 3

[0079]

[0080]

[0081] The results in Table 3 above show that for M10 wet-mix mortar, when mixed with 50 kg of waste water, the mortar consistency of the mortar containing the anti-mud wet-mix mortar admixture described in the examples did not change much in machine-made sand with different MB values, indicating that the anti-mud wet-mix mortar admixture provided by the present invention has good adaptability to machine-made sand. Furthermore, machine-made sand with a high MB value has little effect on the consistency and strength of the mortar containing the anti-mud wet-mix mortar admixture described in the examples, demonstrating that the highly adaptable anti-mud wet-mix mortar admixture provided by the present invention has a good anti-mud effect.

[0082] The mortar with the admixture in Comparative Example 1 had a low 7-day mortar strength. The mortar with the admixture in Comparative Example 2 had a large influence on the consistency and strength of the mortar due to the use of machine-made sand with a high MB value. The initial consistency and 24h consistency were both low, and the mortar strengths at 7 days and 28 days were also low, failing to meet the design strength requirements.

[0083] From the above, it can be seen that the anti-mud admixture provided by the present invention has good adaptability to machine-made sand and has good anti-mud effect.

[0084] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A highly adaptable mud-blocking functional monomer, characterized in that: The functional monomer is prepared by reacting tertiary amine acrylate with halogenated acid to obtain compound a through quaternization reaction, which is then reacted with chitosan through esterification to obtain compound b, which is then reacted with phosphorus pentoxide through phosphorylation to obtain compound b. The molar ratio of the tertiary amine acrylate to the halogenated acid is 1:(1-1.1); The molar ratio of compound a to chitosan is 1:(1-1.1); The molar ratio of compound b to phosphorus pentoxide is 1:(1-1.1); The tertiary amine acrylate is any one of dimethylaminoethyl acrylate, 3-(dimethylamino)propyl acrylate, or 3-(dimethylamino)butyl acrylate.

2. The highly adaptable mud-blocking functional monomer according to claim 1, characterized in that: The halogenated acid is any one of bromopropionic acid, bromobutyric acid, chloropropionic acid and chlorobutyric acid.

3. The method for preparing a highly adaptable mud-blocking functional monomer according to any one of claims 1 to 2, characterized in that: The method comprises the following steps: (1) reacting tertiary amine acrylate and halogenated acid at 45-75° C. for 4-8 hours, cooling to room temperature, removing the solvent by distillation under reduced pressure, washing, filtering, and drying to obtain a small monomer compound a containing a carboxyl group-containing quaternary ammonium salt cation; (2) putting compound a and 1,2-dichloroethane into a three-necked flask, introducing hydrogen chloride (purity 99.99%) gas, and reacting at room temperature for 0.5-4 hours; then adding chitosan, slowly introducing hydrogen chloride; heating to reflux, distilling off dichloroethane at 45-83° C. The azeotrope of ethane and water is separated into layers in a water separator, and the lower layer of 1,2-dichloroethane is added back into the reaction system. After reacting for 4 to 8 hours, it is cooled to -15°C and filtered. The filter cake is recrystallized with methanol to obtain compound b containing chitosan and quaternary ammonium salt cations; (3) Compound b is added to methanesulfonic acid, and then phosphorus pentoxide is added under reaction conditions of 0 to 5°C. The reaction is mechanically stirred under a nitrogen environment for 2 to 4 hours. After the reaction is completed, the product is precipitated with ether, and then washed, filtered, and dried to obtain a functional monomer.

4. A mud-blocking polycarboxylate water-reducing agent, characterized in that: The water reducer contains the highly adaptable mud-blocking functional monomer according to any one of claims 1 to 2 or the highly adaptable mud-blocking functional monomer obtained by the preparation method according to claim 3.

5. The sludge-blocking polycarboxylate water-reducing agent according to claim 4, characterized in that: The water reducer is obtained by free radical polymerization of a functional monomer, an unsaturated polyether monomer, and an unsaturated carboxylic acid monomer in the presence of an initiator and a chain transfer agent; the molar ratio of the unsaturated polyether monomer, the functional monomer, and the unsaturated carboxylic acid monomer is 1:(1-5.6):(1-7.2).

6. The sludge-blocking polycarboxylate water-reducing agent according to claim 4, characterized in that: The unsaturated polyether monomer is any one of allyl polyoxyethylene ether, methallyl polyoxyethylene ether, isobutyl polyoxyethylene ether or isopentenyl polyoxyethylene ether, or a mixture of two or more in any proportion; the unsaturated carboxylic acid monomer is any one of acrylic acid, methacrylic acid, acryloyl chloride, methacryloyl chloride, maleic acid, maleic anhydride, itaconic acid and itaconic anhydride.

7. The sludge-blocking polycarboxylate water-reducing agent according to claim 4, characterized in that: The initiator is a conventional free radical water-soluble initiator, and its usage is 0.5%-5.0% of the total weight of the unsaturated polyether monomer, the functional monomer, and the unsaturated carboxylic acid monomer; the chain transfer agent is any one of mercaptoethanol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, isopropyl alcohol, hypophosphorous acid, sodium hypophosphite, and potassium hypophosphite, or a mixture of two or more of them in any proportion, and its usage is 0.5%-5.0% of the total weight of the unsaturated polyether monomer, the functional monomer, and the unsaturated carboxylic acid monomer.

8. The method for preparing the mud-blocking polycarboxylate water-reducing agent according to any one of claims 4 to 7, characterized in that: The method comprises the following steps: adding an unsaturated polyether monomer and water into a reaction container, keeping the temperature at 30-50°C, stirring for 20-60 minutes, sequentially adding a functional monomer, an unsaturated carboxylic acid monomer, an initiator and a chain transfer agent into the reaction container, continuing to heat the reaction container, and reacting at 40-80°C for 2-10 hours; after the reaction is completed, neutralizing the reaction with an alkaline solution with a mass fraction of 20%-75%, and cooling the reaction to room temperature to obtain a mud-blocking polycarboxylate water-reducing agent.

9. The preparation method according to claim 8, characterized in that: The pH value of the mud-blocking polycarboxylate water-reducing agent is 6.0-8.0, and the solid content is 35%-50%.

10. An application of a mud-blocking polycarboxylate water-reducing agent, characterized in that: When the water reducer is used as an admixture for cement-based materials, its dosage (solid dosage) is 0.05%-0.17% of the mass of the cementitious material; the water reducer is the mud-retarding polycarboxylate water reducer according to any one of claims 4 to 7 or the mud-retarding polycarboxylate water reducer obtained by the preparation method according to any one of claims 8 to 9.

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