CN112745464A - Phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer and preparation method and application thereof - Google Patents
Phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer and preparation method and application thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
- C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
- C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/243—Phosphorus-containing polymers
- C04B24/246—Phosphorus-containing polymers containing polyether side chains
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
- C04B2103/302—Water reducers
Abstract
The invention provides a phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer, and a preparation method and application thereof, and relates to the technical field of concrete admixtures. The high-adaptability early-strength polycarboxylate superplasticizer containing phosphate ester is prepared by copolymerizing 90-110 parts of unsaturated polyether macromonomer, 10-20 parts of unsaturated carboxylic acid and 1-6 parts of acrylamide free radical containing phosphate group. The polyacrylic acid derivative and the polyether side chain on the molecular chain of the water reducing agent provide dispersing performance, the phosphate-containing polyacrylamide improves the adaptability of the water reducing agent due to the existence of phosphate groups, and the amide group balances the retarding effect of the phosphate groups and improves the early strength effect of the product, so that the phosphate-containing polyacrylamide has better adaptability and early strength effect when being used for mixing different types of cement and high-mud-content aggregate concrete.
Description
Technical Field
The invention relates to the technical field of concrete admixtures, in particular to a phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer, and a preparation method and application thereof.
Background
In the field of civil engineering, polycarboxylic acid water reducing agents have been widely used for adjusting and improving the working properties of concrete, and have gradually developed into essential basic raw materials in the production process of high-performance concrete. However, with the increasing awareness of environmental protection in society at present, natural high-quality sandstone aggregate is gradually in short supply, and construction recycled waste, machine-made sand, high-mud content aggregate and low-quality fly ash/slag are widely used for the production of ready-mixed concrete. However, the high dispersibility of the polycarboxylic acid water reducing agent can cause the mixing amount of the polycarboxylic acid water reducing agent in concrete to be low, so that the polycarboxylic acid water reducing agent is sensitive to the content of mud powder in low-quality aggregate, has poor compatibility with other raw materials, is easy to have a series of problems of segregation, bleeding, working performance loss and the like after being mixed with the concrete, and is not beneficial to further popularization and application.
In order to reduce the sensitivity of polycarboxylic acid water reducing agents, water reducing agents with different molecular morphologies, different copolymerization structures and different adsorption capacities have been reported, and the introduction of phosphate groups into the molecular structure of the water reducing agent is most effective. Compared with carboxyl containing only one negative charge, the phosphate ester contains two negative charges, has stronger adsorption capacity and speed, and is preferentially adsorbed on the surfaces of the stone powder and the clay, so that the adsorption of the carboxyl on cement particles is avoided, and the adsorption and dispersion properties of the polycarboxylic acid water reducing agent are ensured. Chinese patent CN 105837768B discloses a polyphosphate water reducing agent, which has better water reducing rate and slump retaining performance when the total mass of the monomer is 0.8% of that of an isopentenol polyoxyethylene ether phosphate monomer. The Chinese patent CN 105418857B fully esterifies alcoholic hydroxyl group in the polycarboxylate superplasticizer prepolymer with inorganic phosphoric acid such as phosphoric acid, polyphosphoric acid and pyrophosphoric acid, and the obtained superplasticizer has good adaptability to clay in different types of cement and sand.
The research work shows that the existence of the phosphate ester improves the adaptability of the polycarboxylate superplasticizer to different materials. In practice, however, the engineer has found that the incorporation of phosphate esters also retards the hydration process of the cement to varying degrees. For example, Wang et al found that when the content of phosphate group-containing HN-101 retarder in concrete was 0.03% -0.07%, the initial setting and final setting time of concrete were both delayed by 90 minutes (synthesis and performance evaluation of novel phosphate group retarder, novel building material, 2020, 47(05): 130-. Chinese patent CN 105754047B discloses a high-adaptability polycarboxylate water reducer containing phosphate ester, which greatly improves the dispersion property and slump-retaining property of the water reducer, especially the adaptability to sulfate and the ability to delay the hydration of ettringite by introducing unsaturated phosphate ester monomer and ammonium acetate in the preparation process of a comb-shaped water reducer. The main reason is that phosphate is hydrolyzed in the alkaline slurry to release phosphate ions and micromolecular diol, which react with calcium ions on the surface of cement to form phosphate to hinder the generation of ettringite, thereby playing the role of a retarder to a certain extent and improving the slump retaining capacity of the water reducer. Chinese patent CN 106008593B discloses a high slump retaining type polycarboxylate water reducing agent containing phosphate, and concrete trial results show that after being mixed for 2 hours, the slump and the expansion of the concrete are almost free from loss, and the comprehensive performance of the water reducing agent is excellent. The phosphino ether polycarboxylic acid water reducing agent (HPCE) synthesized by Chenxin and the like has stronger slump retaining capability than a comb water reducing agent, but the 3d compressive strength is reduced by about 1MPa, and the 7d compressive strength is reduced by 2-3MPa (synthesis and performance research of the phosphino polycarboxylic acid water reducing agent, a novel building material, 2019, 46(08): 17-20.). From these examples, it can be seen that the water reducing agent containing phosphate ester can improve the slump retaining performance of the product due to the retarding effect of phosphate ester, but the early strength of the concrete mixed by the water reducing agent is low, so that the improvement effect of the adaptability of the concrete is limited to a certain extent. Therefore, the content of the phosphate ester in the polycarboxylate water reducer is strictly controlled.
In addition, in practical application, the early strength agents (sodium sulfate, calcium nitrate, triethanolamine and polyacrylamide) for compound concrete can improve the retardation effect of phosphate, but the dosage is difficult to control, the concrete shrinkage is easy to increase and crack, and a certain incompatibility problem exists, so that the polycarboxylic acid water reducing agent is slightly flocculated and separated out, and the product performance is reduced.
Disclosure of Invention
In order to solve the problem that the early strength of the phosphate-group-containing water reducing agent mixed with concrete is lower, the invention provides a high-adaptability early-strength polycarboxylate water reducing agent containing a phosphate acrylamide functional monomer, wherein phosphate groups improve the adaptability of the water reducing agent, amide groups neutralize the retarding effect of phosphate, and the early strength of the concrete is ensured.
The invention also aims to provide a preparation method of the phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer.
In order to achieve the purpose, the invention adopts the following technical scheme:
a phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is characterized in that: the modified polyether is prepared by copolymerizing unsaturated polyether macromonomer, unsaturated carboxylic acid and acrylamide containing phosphoric acid groups, and the formula of the chemical structure of the modified polyether is as follows:
in the formula, R1Is H or CH3；R2Is CH2Or CH2CH2N is the number of structural units, and n is an integer of 10-100; r3H, Na or K; r4Is CH2CH2、CH2CH2CH2、CH2CH2CH2CH2、CH(CH3)CH2CH2、C(CH3)2CH2(ii) a And x, y and z are polymerization degrees and are integers.
The unsaturated polyether macromonomer is polyoxyethylene ether with one end containing double bonds and the other end being methyl-terminated, and the number average molecular weight (M) of the unsaturated polyether macromonomern) Between 500 and 5000 g/mol. When R is1When H, the unsaturated polyether is selected from one or more of allyl polyoxyethylene ether and alkene butyl polyoxyethylene ether; when R is1＝CH3When the unsaturated polyether is selected from one or more of isobutylene polyoxyethylene ether and isoamylene polyoxyethylene ether.
The unsaturated carboxylic acid is acrylic acid and derivatives thereof, when R is1When H, the unsaturated carboxylic acid is selected from one or more of acrylic acid, sodium acrylate, potassium acrylate; when R is1＝CH3When the unsaturated carboxylic acid is selected from one or more of methacrylic acid, sodium methacrylate and potassium methacrylate.
The phosphoric acid group-containing acrylamide is a monomer simultaneously containing double bonds, acylamino and phosphoric acid groups. When R is4＝CH2CH2When the phosphoric acid group acrylamide is 2-acrylamide-ethyl phosphoric acid; when R is4＝CH2CH2CH2When the phosphoric acid acrylamide is 2-acrylamido-propyl phosphoric acid; when R is4＝CH2CH2CH2CH2When the phosphoric acid acrylamide is 2-acrylamide-butyl phosphoric acid; when R is4＝CH(CH3)CH2CH2When the phosphoric acid acrylamide is 2-acrylamide-1-methyl propanephosphoric acid; when R is4＝C(CH3)2CH2When the phosphoric acid acrylamide is 2-acrylamide-2-methyl propyl phosphoric acid.
The high-adaptability early-strength polycarboxylate water reducer containing phosphate ester is a high-molecular copolymer, wherein a high-molecular chain contains three chain segments of polyoxyethylene ether, polyacrylic acid derivatives and polyacrylamide containing phosphate groups, and the high-adaptability early-strength polycarboxylate water reducer can be synthesized by unsaturated polyether macromonomer, unsaturated carboxylic acid and acrylamide containing phosphate groups through free radical copolymerization, wherein 90-110 parts of unsaturated polyether macromonomer, 10-20 parts of unsaturated carboxylic acid and 1-6 parts of acrylamide containing phosphate groups are used. Preferably, 100 parts of unsaturated polyether macromonomer, 15 parts of unsaturated carboxylic acid and 2 parts of phosphate group-containing acrylamide. More preferably, 105 parts of unsaturated polyether macromonomer, 17 parts of unsaturated carboxylic acid and 3 parts of phosphate group-containing acrylamide.
According to the prior art of the polycarboxylate superplasticizer, the high-adaptability early-strength polycarboxylate superplasticizer is obtained by adopting free radical solution polymerization. The technicians in the field can select specific polymerization reaction conditions according to the molecular structure and the target molecular weight of the high-adaptive early-strength polycarboxylate superplasticizer by combining the existing polymer synthesis technology.
A preparation method of a phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is characterized by comprising the following steps:
feeding for the first time: adding water and unsaturated polyether macromonomer into a reaction kettle, uniformly stirring to obtain an unsaturated polyether macromonomer aqueous solution with the mass concentration of 10-60%, adding 0.5-2.0 parts of oxidant with the mass concentration of 25% once again, and controlling the temperature of the reaction kettle at 10-60 ℃;
and (3) feeding for the second time: beginning to dropwise add 50 mass percent aqueous solution of unsaturated carboxylic acid monomer, beginning to dropwise add 10 mass percent aqueous solution consisting of 0.1-0.5 part of reducing agent and 0.5-1.0 part of chain transfer agent within 2-5 minutes, beginning to dropwise add 10 mass percent aqueous solution of phosphate group-containing acrylamide monomer within 10-90 minutes, wherein the whole dropwise add time lasts for 2.0-4.0 hours, and the curing lasts for 0.5-1.5 hours after the dropwise add is finished;
preparation of a product: and after the polymerization reaction is finished, slowly adding 30-100 parts of industrial sodium hydroxide or industrial potassium hydroxide solution with the mass concentration of 30%, uniformly stirring, and standing to obtain a precipitate, namely the high-adaptability early-strength polycarboxylate superplasticizer.
In the first feeding, the mass concentration of the unsaturated polyether macromonomer aqueous solution is 10-60%, preferably 30%, more preferably 50%. The amount of the 25% by mass of the oxidizing agent is 0.5 to 2.0 parts, preferably 1.0 part, and more preferably 1.4 parts. The temperature of the reaction kettle is 10-60 ℃, preferably the temperature is 25 ℃, and more preferably the temperature is 30 ℃.
In the second feeding, the dropping of the aqueous solution of the reducing agent and the chain transfer agent was started within 5 minutes after the dropping of the aqueous solution of the unsaturated carboxylic acid was started. Wherein, the reducing agent is used in an amount of 0.1 to 0.5 parts, preferably 0.25 parts, and more preferably 0.3 parts; the chain transfer agent is used in an amount of 0.5 to 1.0 part, preferably 0.6 part, more preferably 0.8 part. The dropping of the aqueous solution containing 10% by mass of the phosphoric acid group-containing acrylamide monomer is started 10 minutes after the start of the dropping of the aqueous solution of the unsaturated carboxylic acid, more preferably 30 minutes, most preferably 60 minutes, but not more than 90 minutes. In the second addition, the whole dropping time should last 2.0 to 4.0 hours, preferably the dropping time is 3 hours, more preferably the dropping time is 3.5 hours. After the dropwise addition is completed, the polymerization reaction should be continuously cured for 0.5-1.5 hours, preferably the curing time is 1.0 hour, so as to ensure the completion of the polymerization reaction and improve the monomer conversion rate.
When the product is prepared, adding 30% industrial sodium hydroxide or potassium hydroxide solution after the reaction is finished, neutralizing part or all of the polyacrylic acid derivative, and adjusting the pH of the solution to be neutral or weakly acidic, wherein the dosage of the solution is 30-100 parts, preferably 50 parts, and more preferably 75 parts.
The oxidant is selected from: one or more of hydrogen peroxide, sodium persulfate, potassium persulfate and ammonium persulfate. Preferably, the oxidant is ammonium persulfate; more preferably the oxidizing agent is hydrogen peroxide
The reducing agent is selected from: one or more of sodium formaldehyde sulfoxylate, L-ascorbic acid, sodium bisulfite and sodium hypophosphite. Preferably, the reducing agent is sodium hypophosphite; more preferably, the reducing agent is L-ascorbic acid.
The chain transfer agent is selected from: one or more of thioglycolic acid, mercaptopropionic acid and sodium methallyl sulfonate. Preferably, the chain transfer agent is thioglycolic acid.
The invention also provides an application of the phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer in concrete.
The application method of the phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is the same as that of a commercial water reducer product, the bending and fixing mixing amount of the polycarboxylate-type polycarboxylate superplasticizer is 0.05-0.30% of the mass of a total cementing material, and the optimal using amount can be determined by performing a concrete premixing experiment according to actual engineering requirements. When in use, the following should be noted: when the mixing amount is low, the water reducing and slump retaining performances of the high-adaptability early-strength polycarboxylate superplasticizer cannot be fully exerted, and the concrete flowability is poor; when the mixing amount is proper, the high-adaptability early-strength polycarboxylate superplasticizer has better adaptability to concrete raw materials with different cement contents and different mud contents, is not easy to have the problems of concrete segregation, bleeding and the like, and is convenient for technicians to use.
The phosphate-containing high-adaptability early-strength polycarboxylate water reducer can be used alone or mixed with at least one of the existing lignin common water reducer, naphthalene high-efficiency water reducer and polycarboxylate water reducer. In addition, besides the concrete water reducing agent mentioned above, the concrete water reducing agent can also be compounded with functional additives such as an air entraining agent, an expanding agent, a retarder, an early strength agent, a tackifier, a viscosity reducer, a shrinkage reducer, a defoaming agent and the like according to requirements.
Compared with the prior art, the invention has the following beneficial effects:
according to the phosphate-containing high-adaptability early-strength polycarboxylate water reducer, high-content phosphate groups and amide groups are introduced into the structure of a common comb-shaped water reducer, wherein the phosphate groups improve the adaptability of the product, the amide groups balance the retarding action of the phosphate groups, the early strength of concrete is improved, and the phosphate-containing high-adaptability early-strength polycarboxylate water reducer is particularly suitable for mixing concrete of different cement varieties and high-mud-content aggregate. The two groups have synergistic effect to improve the stability of the water reducing agent and avoid the incompatibility problem caused by compounding the early strength agent. In addition, the water reducing agent has simple preparation technology, is convenient for large-scale industrial production, has good compatibility with other types of additive products, and is convenient for technical personnel to use in a compounding way.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a general chemical structure formula of the phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer of the invention, wherein R is1Is H or CH3；R2Is CH2Or CH2CH2N is the number of structural units, and n is an integer of 10-100; r3H, Na or K; r4Is CH2CH2、CH2CH2CH2、CH2CH2CH2CH2、CH(CH3)CH2CH2、C(CH3)2CH2(ii) a And x, y and z are polymerization degrees and are integers.
Detailed Description
In order that the invention may be more fully understood, reference will now be made to the following description. The following is a description of preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, technical means and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
Example 1
A phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is prepared by the following method:
1) feeding for the first time: 810g of water and 90g of allyl polyoxyethylene ether (M)n1500g/mol) is added into a reaction kettle, the mixture is stirred evenly to obtain 10 percent allyl polyoxyethylene ether aqueous solution, 0.5g of 25 percent hydrogen peroxide is added once again, and the temperature of the reaction kettle is controlled at 15 ℃;
2) and (3) feeding for the second time: starting to add a mixed solution of 10g of acrylic acid and 10g of water, starting to add a mixed aqueous solution of 6g consisting of 0.1g of sodium formaldehyde sulfoxylate and 0.5g of thioglycolic acid in a dropwise manner within 2 minutes, starting to add a mixed aqueous solution of 30g containing 3g of 2-acrylamido-ethylphosphoric acid in a dropwise manner within 10 minutes, continuing the whole dropwise addition for 2.0 hours, and continuing to age for 0.5 hour after the dropwise addition is finished;
3) preparation of a product: after the polymerization reaction is finished, slowly adding 30g of industrial sodium hydroxide solution with the mass concentration of 30%, uniformly stirring, and standing to obtain the high-adaptability early-strength polycarboxylate superplasticizer.
Example 2
A phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is prepared by the following method:
1) feeding for the first time: 538g of water and 95g of polyoxyethylene isobutylene ether (M)n2000g/mol) is added into a reaction kettle, after being uniformly stirred, 15 percent of isobutylene polyoxyethylene ether aqueous solution is obtained, 0.6g of 25 percent sodium persulfate is added once again, and the temperature of the reaction kettle is controlled at 17 ℃;
2) and (3) feeding for the second time: starting to add dropwise a mixed solution of 13g of sodium acrylate and 13g of water, starting to add dropwise a mixed aqueous solution of 8g consisting of 0.2g of L-ascorbic acid and 0.6g of mercaptopropionic acid within 3 minutes, starting to add dropwise a mixed aqueous solution of 10g containing 1g of 2-acrylamido-propylphosphoric acid within 25 minutes, the whole dropwise addition time lasting for 2.5 hours, and continuing to age for 1.0 hour after the completion of the dropwise addition;
3) preparation of a product: after the polymerization reaction is finished, slowly adding 35g of industrial potassium hydroxide solution with the mass concentration of 30%, uniformly stirring, and standing to obtain the high-adaptability early-strength polycarboxylate superplasticizer.
Example 3
A phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is prepared by the following method:
1) feeding for the first time: 233g of water and 100g of vinylbutylpolyoxyethylene ether (M)n3000g/mol) is added into a reaction kettle, the mixture is evenly stirred to obtain an aqueous solution of the alkene butyl polyoxyethylene ether with the mass concentration of 30 percent, and 0.8g of mass concentration is added into the aqueous solution once againControlling the temperature of the reaction kettle at 30 ℃ for 25 percent of potassium persulfate;
2) and (3) feeding for the second time: starting to add a mixed solution of 14g of methacrylic acid and 14g of water, starting to add a mixed aqueous solution of 11g consisting of 0.3g of sodium bisulfite and 0.8g of sodium methallylsulfonate within 4 minutes, starting to add a mixed aqueous solution of 30g containing 3g of 2-acrylamido-butylphosphonic acid within 30 minutes, continuing the entire addition for 3.0 hours, and continuing to age for 1.5 hours after the addition is finished;
3) preparation of a product: after the polymerization reaction is finished, 50g of industrial sodium hydroxide solution with the mass concentration of 30% is slowly added, and the high-adaptability early-strength polycarboxylate superplasticizer can be obtained by stirring uniformly and standing.
Example 4
A phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is prepared by the following method:
1) feeding for the first time: 157.5g of water and 105g of isopentenyl polyoxyethylene ether (M)n500g/mol) is added into a reaction kettle, after being uniformly stirred, a 40% isopentene polyoxyethylene ether aqueous solution is obtained, 1.0g of 25% ammonium persulfate with mass concentration is added once again, and the temperature of the reaction kettle is controlled at 35 ℃;
2) and (3) feeding for the second time: beginning to dropwise add a mixed solution of 15g of potassium acrylate and 15g of water, beginning to dropwise add a mixed aqueous solution of 15g consisting of 0.5g of sodium hypophosphite and 1.0g of thioglycolic acid within 4 minutes, beginning to dropwise add a mixed aqueous solution of 50g containing 5g of 2-acrylamido-1-methylpropyl phosphoric acid within 60 minutes, wherein the whole dropwise adding time lasts for 3.5 hours, and the aging lasts for 1.3 hours after the dropwise adding is finished;
3) preparation of a product: after the polymerization reaction is finished, 80g of industrial potassium hydroxide solution with the mass concentration of 30% is slowly added, and the high-adaptability early-strength polycarboxylate superplasticizer can be obtained by stirring uniformly and standing.
Example 5
A phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is prepared by the following method:
1) feeding for the first time: 110g of water and 110g of vinylbutyl polyoxyethylene ether (M)n4000g/mol) was added to the reactionIn the kettle, uniformly stirring to obtain an aqueous solution of the alkenyl butyl polyoxyethylene ether with the mass concentration of 50%, adding 1.6g of hydrogen peroxide with the mass concentration of 25% once again, and controlling the temperature of the reaction kettle at 45 ℃;
2) and (3) feeding for the second time: starting to add a mixed solution of 20g of a potassium methacrylate salt and 20g of water, starting to add a mixed aqueous solution of 13g consisting of 0.4g of sodium hydrogen sulfite and 0.9g of mercaptopropionic acid in a dropwise manner within 5 minutes, starting to add an aqueous solution of 60g consisting of 6g of a phosphoric acid acrylamide monomer in a dropwise manner within 90 minutes, continuing the entire dropwise addition for 4.0 hours, and continuing to age for 1.5 hours after the completion of the dropwise addition;
3) preparation of a product: after the polymerization reaction is finished, slowly adding 100g of industrial sodium hydroxide solution with the mass concentration of 30%, uniformly stirring, and standing to obtain the high-adaptability early-strength polycarboxylate superplasticizer.
Example 6
A phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is prepared by the following method:
1) feeding for the first time: 70g of water and 105g of polyoxyethylene isobutylene ether (M)n5000g/mol) is added into a reaction kettle, after being uniformly stirred, an isobutylene polyoxyethylene ether aqueous solution with the mass concentration of 60% is obtained, 2.0g of sodium persulfate with the mass concentration of 25% is added once again, and the temperature of the reaction kettle is controlled at 60 ℃;
2) and (3) feeding for the second time: beginning to add a mixed solution of 18g of potassium acrylate and 18g of water, beginning to add 11g of a mixed aqueous solution consisting of 0.3g of L-ascorbic acid and 0.8g of thioglycolic acid within 4 minutes, beginning to add 40g of a mixed aqueous solution containing 4g of 2-acrylamido-2-methylpropanephosphoric acid within 90 minutes, continuing the adding for 3.5 hours for the whole adding time, and continuing to age for 1.2 hours after the adding is finished;
3) preparation of a product: after the polymerization reaction is finished, 60g of industrial sodium hydroxide solution with the mass concentration of 30% is slowly added, and the high-adaptability early-strength polycarboxylate superplasticizer can be obtained by stirring uniformly and standing.
Comparative example 1
A common polycarboxylic acid water reducing agent is prepared by the following method:
1) feeding for the first time: will be provided with70g of water and 105g of allyl polyoxyethylene ether (M)n3500g/mol) is added into a reaction kettle, the mixture is stirred evenly to obtain 60 percent allyl polyoxyethylene ether aqueous solution, 2.0g of 25 percent hydrogen peroxide solution is added once, and the temperature of the reaction kettle is controlled at 60 ℃;
2) and (3) feeding for the second time: starting to add a mixed solution of 18g of acrylic acid and 18g of water, starting to add 11g of mixed aqueous solution consisting of 0.3g of L-ascorbic acid and 0.8g of thioglycolic acid in 4 minutes, continuing the whole adding time for 3.5 hours, and continuing to age for 1.2 hours after the adding is finished;
3) preparation of a product: and after the polymerization reaction is finished, slowly adding 60g of industrial sodium hydroxide solution with the mass concentration of 30%, uniformly stirring, and standing to obtain the common polycarboxylic acid water reducing agent.
Comparative example 2
A common polycarboxylic acid water reducing agent is prepared by the following method:
1) feeding for the first time: 157.5g of water and 105g of ethylenebutyl polyoxyethylene ether (M)n2500g/mol) is added into a reaction kettle, after being uniformly stirred, the water solution of the alkene butyl polyoxyethylene ether with the mass concentration of 40% is obtained, 1.0g of ammonium persulfate with the mass concentration of 25% is added once again, and the temperature of the reaction kettle is controlled at 35 ℃;
2) and (3) feeding for the second time: starting to add a mixed solution of 15g of methacrylic acid and 15g of water dropwise, and then starting to add 15g of a mixed aqueous solution consisting of 0.5g of sodium formaldehyde sulfoxylate and 1.0g of mercaptopropionic acid dropwise over 4 minutes, wherein the whole dropwise addition time lasts for 3.5 hours, and aging lasts for 1.3 hours after the dropwise addition is finished;
3) preparation of a product: after the polymerization reaction is finished, 80g of industrial potassium hydroxide solution with the mass concentration of 30% is slowly added, and the mixture is stirred uniformly and then stands to obtain the common comb-type polycarboxylic acid water reducing agent.
Experimental example 1
The purpose of this experimental example is to evaluate the dispersing performance of the phosphate-containing high-early-strength polycarboxylate superplasticizer prepared by the invention on different types of cement, and the cement used is red lion cement (P.O 42.5.5R), conch cement (P.O 42.5.5R), Huarun cement (P.O 42.5.5R) and Taiwan cement (P.O 42.5.5R). The fluidity of the cement paste is tested according to the standard GB/T8077-2012 concrete admixture homogeneity test method, during the test, 300g of cement is added with 90g of water, the cement paste flows on a glass plate for 30s after being uniformly stirred, the fluidity of the cement paste is tested after 1h after the stirring, and the test results are shown in Table 1.
TABLE 1 Cement paste fluidity (mm)
According to the data in the table 1, the high-adaptability early-strength polycarboxylate water reducer containing phosphate ester prepared by the invention still has good dispersing performance on different cement varieties and shows excellent fluidity retaining capability under the condition of low mixing amount; the comparative example has larger dispersion performance fluctuation to different cement varieties, and the difference of fluidity retention capacity is obvious; the commercial products 1 and 2 are phosphate-containing water reducing agents, and the adaptability of the phosphate-containing water reducing agents is basically equivalent to that of high-adaptability early-strength polycarboxylate water reducing agents. In conclusion, the product of the invention has excellent adaptability to different varieties of cement, and the sensitivity of the product is reduced.
Experimental example 2
The purpose of the experimental example is to represent the early strength effect of the phosphate-containing high-adaptability early strength type polycarboxylate water reducer, and the C30 concrete is mixed by referring to the related method of GB/T8076-. The test adopts sea snail cement (P.O 42.5.5R), medium sand with fineness modulus of 2.6, 3.0% of mud content, crushed stone with grain diameter of 5-20mm and continuous gradation, the water cement ratio is 0.44, the mixing amount of the water reducing agent is 0.20% of the folding mixing amount, and the slump, the expansion degree and the gas content of the fresh concrete and the compression strength of 3d, 7d and 28d after forming are tested, and the test results are shown in Table 2.
TABLE 2 concrete Performance test results
As can be seen from Table 2, the high-adaptability early-strength polycarboxylate water reducer containing phosphate ester prepared by the invention has better working performance when being mixed with concrete, and compared with comparative examples and similar products sold in the market, the products of the invention have obviously improved 3d, 7d and 28d strength, which shows that the products have obvious advantages in improving concrete strength, especially early strength, in concrete.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the spirit of the present invention, and these changes and modifications are within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A phosphate-containing high-adaptability early-strength polycarboxylate superplasticizer is characterized by comprising the following chemical structural general formula:
in the formula, R1Is H or CH3，R2Is CH2Or CH2CH2N is an integer, n is more than or equal to 10 and less than or equal to 100;
R3h, Na or K;
R4is CH2CH2、CH2CH2CH2、CH2CH2CH2CH2、CH(CH3)CH2CH2、C(CH3)2CH2Any one of the above;
x, y and z are integers.
2. The high-adaptability early-strength polycarboxylate superplasticizer according to claim 1, characterized by being prepared by copolymerizing 90-110 parts of unsaturated polyether macromonomer, 10-20 parts of unsaturated carboxylic acid and 1-6 parts of phosphate-group-containing acrylamide.
3. The high-adaptability early-strength polycarboxylate water reducer according to claim 2, characterized in that the unsaturated polyether macromonomer is selected from one or more of allyl polyoxyethylene ether, isobutylene polyoxyethylene ether, alkenyl polyoxyethylene ether and isoamylene polyoxyethylene ether.
4. The high-adaptive early-strength polycarboxylate water reducer according to claim 2, wherein the unsaturated carboxylic acid is selected from one or more of acrylic acid, sodium acrylate salt, potassium acrylate salt, methacrylic acid, sodium methacrylate salt and potassium methacrylate salt.
5. The high-adaptive early-strength polycarboxylate water reducer according to claim 2, wherein the phosphate-containing acrylamide is selected from one or more of 2-acrylamido-ethyl phosphoric acid, 2-acrylamido-propyl phosphoric acid, 2-acrylamido-butyl phosphoric acid, 2-acrylamido-1-methylpropanephosphoric acid, and 2-acrylamido-2-methylpropanephosphoric acid.
6. The preparation method of the high-adaptability early-strength polycarboxylate superplasticizer according to any one of claims 1 to 5, characterized by comprising the following steps:
(1) feeding for the first time: adding 0.5-2.0 parts of oxidant into 90-110 parts of unsaturated polyether macromonomer, heating and stirring for reaction;
(2) and (3) feeding for the second time: adding 10-20 parts of unsaturated carboxylic acid into the reaction liquid in the step (1), then adding 0.1-0.5 part of reducing agent and 0.5-1.0 part of chain transfer agent, then adding 1-6 parts of acrylamide containing phosphoric acid groups, and then carrying out reaction;
(3) preparation of a product: and (3) after the reaction in the step (2) is finished, adding 10-30 parts of sodium hydroxide or potassium hydroxide into the mixture, uniformly stirring the mixture, and standing the mixture to obtain the high-adaptability early-strength polycarboxylate superplasticizer.
7. The preparation method of the high-adaptability early-strength polycarboxylate superplasticizer according to claim 6, wherein the reaction temperature in the step (1) is 10-60 ℃.
8. The preparation method of the high-adaptive early strength type polycarboxylate water reducer as claimed in claim 6, wherein the step (2) is performed by dropwise adding, the phosphoric acid acrylamide is dropwise added within 10-90 minutes after the reducing agent and the chain transfer agent are dropwise added, the adding time of the step (2) lasts 2.0-4.0 hours totally, and the reaction time of the step (2) is 0.5-1.5 hours.
9. The preparation method of the high-adaptability early-strength polycarboxylate water reducer according to claim 6, characterized in that the oxidant is one or more selected from hydrogen peroxide, sodium persulfate, potassium persulfate and ammonium persulfate;
the reducing agent is selected from one or more of sodium formaldehyde sulfoxylate, L-ascorbic acid, sodium bisulfite and sodium hypophosphite;
the chain transfer agent is selected from one or more of thioglycolic acid, mercaptopropionic acid and sodium methallyl sulfonate.
10. The use of the high-adaptability early-strength polycarboxylate water reducer as defined in any one of claims 1-5 in concrete.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112724414A (en) * | 2021-01-21 | 2021-04-30 | 江苏奥莱特新材料股份有限公司 | Polycarboxylate superplasticizer with polyphosphonate side chains and preparation method thereof |
| CN113444210A (en) * | 2021-06-30 | 2021-09-28 | 河北红墙新材料有限公司 | Low-sensitivity water-reducing slump-retaining polycarboxylic acid water reducer and preparation method thereof |
| CN116478343A (en) * | 2023-06-25 | 2023-07-25 | 北京鼎瀚中航建设有限公司 | Viscosity-reducing polycarboxylate superplasticizer and preparation method thereof |
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| CN104177557A (en) * | 2014-08-22 | 2014-12-03 | 科之杰新材料集团有限公司 | Low-temperature preparation method of high-adaptability ether polycarboxylic acid water reducer |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104177557A (en) * | 2014-08-22 | 2014-12-03 | 科之杰新材料集团有限公司 | Low-temperature preparation method of high-adaptability ether polycarboxylic acid water reducer |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112724414A (en) * | 2021-01-21 | 2021-04-30 | 江苏奥莱特新材料股份有限公司 | Polycarboxylate superplasticizer with polyphosphonate side chains and preparation method thereof |
| CN112724414B (en) * | 2021-01-21 | 2022-06-14 | 江苏奥莱特新材料股份有限公司 | Polycarboxylate superplasticizer with polyphosphonate side chains and preparation method thereof |
| CN113444210A (en) * | 2021-06-30 | 2021-09-28 | 河北红墙新材料有限公司 | Low-sensitivity water-reducing slump-retaining polycarboxylic acid water reducer and preparation method thereof |
| CN116478343A (en) * | 2023-06-25 | 2023-07-25 | 北京鼎瀚中航建设有限公司 | Viscosity-reducing polycarboxylate superplasticizer and preparation method thereof |
| CN116478343B (en) * | 2023-06-25 | 2023-09-26 | 北京鼎瀚中航建设有限公司 | Viscosity-reducing polycarboxylate superplasticizer and preparation method thereof |
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