CN112608427B - Shrinkage-reducing polycarboxylate superplasticizer and preparation method and application thereof - Google Patents
Shrinkage-reducing 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
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/2641—Polyacrylates; Polymethacrylates
- C04B24/2647—Polyacrylates; Polymethacrylates containing polyether side chains
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/2664—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of ethylenically unsaturated dicarboxylic acid polymers, e.g. maleic anhydride copolymers
- C04B24/267—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of ethylenically unsaturated dicarboxylic acid polymers, e.g. maleic anhydride copolymers 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
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Abstract
The invention relates to the technical field of a reduction type polycarboxylate water reducer for cement concrete, in particular to a reduction type polycarboxylate water reducer and a preparation method and application thereof. The preparation method provided by the invention comprises the following steps: mixing unsaturated carboxylic acid, unsaturated carboxylic acid hydroxy ester, unsaturated polyoxyethylene ether, water, a molecular weight regulator and an initiator to perform polymerization reaction to obtain a solid copolymerization product; mixing the solid copolymerization product, mercury salt, lower olefin and an organic solvent to perform an alkoxy mercurization reaction to obtain an alkoxy mercurization product; and dropwise adding a sodium borohydride-sodium hydroxide aqueous solution into the alcoxyl mercurizing product to perform demercuration reaction, thereby obtaining the reduction type carboxylic acid water reducing agent. According to the preparation method, a reduction type functional monomer does not need to be copolymerized, the original water reducing function can be still kept, the working energy efficiency is greatly improved, and the types and the application of the polycarboxylate superplasticizer in concrete are enriched.
Description
Technical Field
The invention relates to the technical field of a reduction type polycarboxylate water reducer for cement concrete, in particular to a reduction type polycarboxylate water reducer and a preparation method and application thereof.
Background
With the continuous development and progress of high-performance concrete technology, higher requirements are put forward on the rheological property of fresh concrete and the dimensional stability of hardened concrete, and the concrete chemical admixture is required to play an important function to achieve the aim. As is well known, the chemical admixture for polymer synthesis generally has the advantages of strong molecular designability, low mixing amount, high energy efficiency, good compatibility with cement concrete systems and the like, and is gradually becoming an indispensable component for regulating and improving the concrete performance. Therefore, designing and synthesizing chemical admixture with multifunctional performance has become one of the great demands of concrete engineering at present.
The high fluidity of the fresh concrete has very important significance for improving the pumping and plasticizing effects of concrete fluid, and can also save the cement consumption and improve the later strength and construction quality. For hardened concrete, the volume characteristic of low shrinkage rate is beneficial to reducing the risk of shrinkage cracking of concrete, can greatly improve the durability of concrete products, and is more and more favored by construction engineers. Therefore, the synthetic product has excellent water reducing characteristic, the polymer macromolecule is functionalized and modified, the excellent reducing function is introduced, the excellent water reducing and reducing effects are realized through the interaction function of different side faces, the action energy efficiency can be greatly improved, and the synthetic product has obvious application value in actual engineering.
Chinese patent CN201710817075.2 discloses a shrinkage-reducing polycarboxylic acid water reducing agent and a preparation method thereof, which is obtained by copolymerizing an alkenyl polyether macromonomer, acrylic acid, maleic acid monoalkyl ester and maleic acid polyoxyethylene/polyoxypropylene polydimethylsiloxane under the condition that an initiator and a chain transfer agent exist in an aqueous solution at the temperature of 20-80 ℃. The shrinkage-reducing polycarboxylate superplasticizer is doped into concrete, has a good shrinkage-reducing effect under a low doping amount, has a certain water-reducing capacity, and has small influence on the strength of the concrete. However, the invention is not prepared by simple and convenient alcoxyl mercurization and demercuration reaction, and the aim of realizing polymer functionalization by a molecular structure design method cannot be achieved.
Chinese patent CN201910704495.9 discloses a low surface tension reduction type polycarboxylate superplasticizer and a preparation method thereof, wherein a reduction functional macromonomer, a polyhydroxy polymer and water are added into a reaction kettle, and then an initiator aqueous solution, a chain transfer agent aqueous solution and an unsaturated acid aqueous solution are respectively added for copolymerization to obtain the low surface tension reduction type polycarboxylate superplasticizer. The invention introduces the shrinkage reducing functional macromonomer into the polycarboxylic acid molecular structure through copolymerization, so that the polycarboxylic acid molecular structure has a shrinkage reducing functional chain segment, a steric hindrance chain segment and an adsorption group chain segment, and has better dispersing performance and shrinkage reducing effect when being applied to concrete. However, the invention does not design functionalization reactions of polycarboxylic acid macromolecules such as etherification modification and the like, and does not utilize the existing functional groups of the water reducing agent to achieve the improvement of the comprehensive efficiency of the shrinkage reducing agent and the water reducing agent.
The shrinkage-reducing polycarboxylic acid water reducing agent for concrete described in most patents has good effects of reducing water and inhibiting concrete shrinkage. However, the designed synthesis methods all have certain defects, researchers mostly focus on the idea of directly grafting and copolymerizing functional monomers to achieve the purpose of reducing the shrinkage and cracking phenomena of concrete, and rarely utilize the existing groups of the polycarboxylic acid water reducing agent to directly perform functionalization modification, so that the shrinkage reducing function is added on the basis of ensuring the water reducing function. The direct copolymerization of small monomers cannot improve the functionality due to the problems of reactivity ratio matching and the like, but risks of reducing the polymerization conversion rate and weakening the water reducing effect. Therefore, the polycarboxylate superplasticizer related to the requirement not only can retain the original high water-reducing property, but also can obviously inhibit the shrinkage of cement concrete materials, has huge market demand, and has no report on the aspect of work at home and abroad.
Disclosure of Invention
The invention aims to provide a shrinkage-reducing polycarboxylic acid water reducing agent, and a preparation method and application thereof. According to the preparation method, a reduction type functional monomer does not need to be copolymerized, the original water reducing function can be still kept, the working energy efficiency is greatly improved, and the types and the application of the polycarboxylate superplasticizer in concrete are enriched.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a shrinkage-reducing polycarboxylic acid water reducing agent, which comprises the following steps:
mixing unsaturated carboxylic acid, unsaturated carboxylic acid hydroxy ester, unsaturated polyoxyethylene ether, water, a molecular weight regulator and an initiator to perform polymerization reaction to obtain a solid copolymerization product;
mixing the solid copolymerization product, mercury salt, lower olefin and an organic solvent to perform an alkoxy mercurization reaction to obtain an alkoxy mercurization product;
and dropwise adding a sodium borohydride-sodium hydroxide aqueous solution into the alcoxyl mercurizing product to perform demercuration reaction, thereby obtaining the reduction type carboxylic acid water reducing agent.
Preferably, the unsaturated carboxylic acid is acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid;
the unsaturated carboxylic hydroxyl ester is hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate;
the unsaturated polyoxyethylene ether is hydroxypropyl polyoxyethylene ether, isobutylene polyoxyethylene ether or isopentenyl polyoxyethylene ether.
Preferably, the molar ratio of the unsaturated carboxylic acid to the unsaturated carboxylic acid hydroxy ester to the unsaturated polyoxyethylene ether is (1.5-4): (0.5-2): 1.
preferably, the molecular weight regulator is thioglycolic acid, mercaptopropionic acid, sodium methallyl sulfonate or sodium allyl sulfonate;
the initiator is persulfate.
Preferably, the molar ratio of the molecular weight regulator to the initiator to the unsaturated polyoxyethylene ether is (0.05-0.75): (0.05-0.5): 1.
preferably, the mercury salt is mercury acetate or mercury trifluoroacetate;
the molar ratio of the mercury salt to the unsaturated carboxylic acid hydroxy ester is (0.005-0.03): 1;
the lower olefin is 3-methyl-1-pentene, 4-methyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene or 1-hexene;
the molar ratio of the lower olefin to the unsaturated carboxylic acid hydroxy ester is (0.75-1.2): 1.
preferably, the process of the alkoxy amalgamation reaction is as follows: refluxing for 4-10 h under the condition of stirring;
and controlling the distillation temperature of the fractionating column to be 35-40 ℃ in the reflux process.
Preferably, the total mass percentage of the sodium borohydride and the sodium hydroxide in the sodium borohydride-sodium hydroxide aqueous solution is 5-30%;
the mass ratio of the sodium hydroxide to the sodium borohydride is 1: (5-10); the molar ratio of the sodium borohydride to the mercury salt is (0.5-0.8): 1.
the invention also provides a shrinkage-reducing polycarboxylate superplasticizer prepared by the preparation method of the technical scheme, which has a structure shown in formula 1:
wherein R is1Is hydrogen or carboxyl, R2Is hydrogen, methyl or methylenecarboxyl, R3、R4、R6、R7And R9Independently is hydrogen or methyl, R5Is methylene or absent, R8Is methyl, ethyl or isopropyl, R10Is methylene or absent;
the value range of a is 10-30, the value range of b is 5-30, the value range of c is 5-20, and the value range of n is 11-120.
The invention also provides application of the reduction type polycarboxylate superplasticizer in the technical scheme in the field of concrete.
The invention provides a preparation method of a shrinkage-reducing polycarboxylic acid water reducing agent, which comprises the following steps: mixing unsaturated carboxylic acid, unsaturated carboxylic acid hydroxy ester, unsaturated polyoxyethylene ether, water, a molecular weight regulator and an initiator to perform polymerization reaction to obtain a solid copolymerization product; mixing the solid copolymerization product, mercury salt, lower olefin and an organic solvent to perform an alkoxy mercurization reaction to obtain an alkoxy mercurization product; and dropwise adding a sodium borohydride-sodium hydroxide aqueous solution into the alcoxyl mercurizing product to perform demercuration reaction, thereby obtaining the shrinkage-reducing polycarboxylic acid water reducing agent.
Compared with the prior art, the preparation method provided by the invention has the following beneficial effects:
1. according to the invention, unsaturated carboxylic acid hydroxy ester and unsaturated polyoxyethylene ether monomers are copolymerized, and are subjected to alkoxy mercurization and demercuration reaction to form the comb-shaped structure reduction type polycarboxylate water reducer which takes polycarboxylic acid as a main chain and long-chain polyether and short-chain ether as side chains, the structure of the polycarboxylate water reducer is derived from a polycarboxylate water reducer and is higher than that of the polycarboxylate water reducer, the polycarboxylate water reducer for cement concrete is innovated and broken through again, and the thought and direction are widened for the subsequent deep development of new varieties of polycarboxylate water reducers;
2. the shrinkage-reducing polycarboxylate water reducer prepared by the preparation method has a typical comb-shaped macromolecular structure, a polycarboxylate main chain is adsorbed on cement particles, a long polyether side chain can play a steric hindrance role in a cement-water system to provide an excellent water reducing effect, a short chain ether side chain can reduce the evaporation rate of water in a pore solution capillary tube, reduce the additional pressure of the capillary tube and effectively prevent the shrinkage cracking of cement concrete, and the polymer is the shrinkage-reducing polycarboxylate water reducer with unique advantages and shows good application potential and market competitiveness;
3. compared with the traditional polycarboxylic acid water reducing agent, the shrinkage-reducing polycarboxylic acid water reducing agent prepared by the preparation method has the advantages of low energy consumption in the preparation process, simple and controllable condition and temperature, common and easily-obtained reaction raw materials, common chemical reactions of the used graft copolymerization reaction, the alkoxy mercurization reaction and the demercuration reaction, simple and convenient operation process, no expensive reagent, no special requirements on synthesis equipment and experimental environment, and easy realization of industrial production;
4. the shrinkage-reducing polycarboxylate superplasticizer solution prepared by the preparation method is stable in state, uniform and clear, does not deteriorate after long-term storage, can provide a good water-reducing effect for freshly-mixed cement concrete under a low mixing amount, can also provide a good shrinkage-inhibiting effect for hardened cement concrete, has double effects, has water-reducing and shrinkage-reducing performance indexes exceeding national standards and industrial standards, and has good economic benefits and application prospects.
Detailed Description
The invention provides a preparation method of a shrinkage-reducing polycarboxylic acid water reducing agent, which comprises the following steps:
mixing unsaturated carboxylic acid, unsaturated carboxylic acid hydroxy ester, unsaturated polyoxyethylene ether, water, a molecular weight regulator and an initiator to perform polymerization reaction to obtain a solid copolymerization product;
mixing the solid copolymerization product, mercury salt, lower olefin and an organic solvent to perform an alkoxy mercurization reaction to obtain an alkoxy mercurization product;
and dropwise adding a sodium borohydride-sodium hydroxide aqueous solution into the alcoxyl mercurizing product to perform demercuration reaction, thereby obtaining the reduction type carboxylic acid water reducing agent.
In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.
The invention mixes unsaturated carboxylic acid, unsaturated carboxylic acid hydroxy ester, unsaturated polyoxyethylene ether, water, molecular weight regulator and initiator to generate polymerization reaction, and then the solid copolymerization product is obtained.
In the present invention, the unsaturated carboxylic acid is preferably acrylic acid, methacrylic acid, itaconic acid, maleic acid, or fumaric acid; the unsaturated carboxylic acid hydroxyl ester is preferably hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate; the unsaturated polyoxyethylene ether is preferably hydroxypropyl polyoxyethylene ether, isobutenyl polyoxyethylene ether or isopentenyl polyoxyethylene ether; the molecular weight of the unsaturated polyoxyethylene ether is preferably 500-3000.
In the present invention, the molar ratio of the unsaturated carboxylic acid, the unsaturated carboxylic acid hydroxy ester and the unsaturated polyoxyethylene ether is preferably (1.5 to 4): (0.5-2): 1, more preferably (2 to 3.5): (0.8-1.6): 1, most preferably (2.4-3.2): (1.2-1.5): 1.
in the present invention, the molecular weight modifier is preferably thioglycolic acid, mercaptopropionic acid, sodium methallylsulfonate or sodium allylsulfonate; the initiator is preferably a persulfate; the persulfate is preferably one or more of ammonium persulfate, potassium persulfate and sodium persulfate, and when the persulfate is more than two of the specific choices, the proportion of the specific substances is not limited in any way, and the specific substances can be mixed according to any proportion.
In the present invention, the molar ratio of the molecular weight regulator, the initiator and the unsaturated polyoxyethylene ether is preferably (0.05 to 0.75): (0.05-0.5): 1, more preferably (0.10 to 0.6): (0.10-0.4): 1, most preferably (0.3 to 0.5): (0.2-0.3): 1.
in the invention, the solid content of the mixed system obtained after mixing is preferably 30-50%, more preferably 35-45%, and most preferably 38-42%.
In the present invention, the mixing preferably comprises the steps of:
unsaturated carboxylic acid, unsaturated carboxylic acid hydroxy ester, unsaturated polyoxyethylene ether, water and molecular weight regulator are mixed for the first time, and then initiator is added.
In the present invention, the first mixing is preferably performed under stirring, and the stirring is not particularly limited in the present invention and may be performed by a process well known to those skilled in the art.
In the invention, the temperature for adding the initiator is preferably 60-90 ℃, more preferably 65-85 ℃, and most preferably 70-80 ℃; the mode of addition is preferably dropwise. During the dropwise addition, the initiator is preferably added in the form of an aqueous initiator solution; the mass percentage content of the initiator aqueous solution is preferably 1-30%, more preferably 5-25%, and most preferably 10-20%; the dripping time is preferably 1-5 h, and more preferably 2-3 h.
After the dropwise addition is finished, the reaction is preferably continued for 1-5 h at the temperature of 60-90 ℃, and more preferably for 3-4 h.
In the invention, the copolymerization reaction preferably takes the time of starting to add the initiator as the initial time and takes the time of continuing to react for 1-5 hours as the termination time.
In the present invention, the reaction process of the polymerization reaction is preferably:
wherein R is1Is hydrogen or carboxyl, R2Is hydrogen, methyl or methylenecarboxyl, R3、R4、R6、R7And R9Independently is hydrogen or methyl, R5Is methylene or absent, R8Is methyl, ethyl or isopropyl, R10Is methylene or absent;
the value range of a is 10-30, the value range of b is 5-30, the value range of c is 5-20, and the value range of n is 11-120.
In the present invention, when said R is5Is absent and is understood as R5front-CH2Directly with R5The latter-OH linkage;
or R10Is absent and is understood as R10front-CH2Directly with R10The latter-O-linkage.
After the copolymerization reaction is completed, the invention also preferably comprises the step of distilling the obtained product system under reduced pressure, wherein the reduced pressure distillation is carried out by adopting the processes well known to the skilled person in the field and can ensure that water is removed.
After obtaining the solid copolymerization product, the invention mixes the solid copolymerization product, mercury salt, lower olefin and organic solvent to generate the alcoxyl mercurizing reaction to obtain the alcoxyl mercurizing product.
In the present invention, the alkoxymercurization product has a structure represented by formula 2:
wherein R is1Is hydrogen or carboxyl, R2Is hydrogen, methyl or methylenecarboxyl, R3、R4、R6、R7And R9Independently is hydrogen or methyl, R5Is methylene or absent, R8Is methyl, ethyl or isopropyl, R10Is methylene or absent;
the value range of a is 10-30, the value range of b is 5-30, the value range of c is 5-20, and the value range of n is 11-120.
In the present invention, the mercury salt is preferably mercury acetate or mercury trifluoroacetate; the lower olefin is preferably 3-methyl-1-pentene, 4-methyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene or 1-hexene; the organic solvent is preferably one or more of tetrahydrofuran, N-dimethylformamide, sulfolane and dimethyl sulfoxide; when the organic solvent is more than two of the above specific choices, the invention does not have any special limitation on the proportion of the specific substances, and the specific substances can be mixed according to any proportion.
In the present invention, the molar ratio of the mercury salt to the unsaturated carboxylic acid hydroxy ester is preferably (0.005-0.03): 1, more preferably (0.01 to 0.025): 1, most preferably (0.012-0.016): 1; the molar ratio of the lower olefin to the unsaturated carboxylic acid hydroxy ester is preferably (0.75-1.2): 1, more preferably (0.80 to 1.1): 1, more preferably (0.95 to 1.02): 1; the mass ratio of the organic solvent to the total mass of the solid copolymerization product, the mercury salt and the lower olefin is preferably (1-3): 1, more preferably (1.5 to 2.0): 1.
in the present invention, the process of the alkoxymercurization reaction is preferably: refluxing for 4-10 h under the condition of stirring, and preferably 6-8 h; the distillation temperature of the fractionating column is preferably controlled to be 35-40 ℃ in the reflux process.
In the present invention, the reaction process of the alkoxy mercurization reaction is preferably as follows:
after the alcoxyl mercurizing product is obtained, sodium borohydride-sodium hydroxide aqueous solution is dropwise added into the alcoxyl mercurizing product to carry out demercuration reaction, so that the shrinkage-reducing carboxylic acid water reducing agent is obtained.
In the invention, the total mass percentage content of sodium borohydride and sodium hydroxide in the sodium borohydride-sodium hydroxide aqueous solution is preferably 5-30%, more preferably 12-23%, and most preferably 16-20%; the mass ratio of the sodium hydroxide to the sodium borohydride is preferably 1: (5-10), more preferably 1: (6-8); the preferable molar ratio of the amount of the sodium borohydride to the mercury salt is (0.5-0.8): 1, more preferably (0.6 to 0.7): 1.
in the present invention, the dropwise addition is preferably carried out under stirring, and the stirring is not particularly limited in the present invention and may be carried out by a procedure well known to those skilled in the art. In the invention, the dripping temperature is preferably 20-25 ℃, and the dripping time is preferably 2-5 h. In the invention, the completion of the dropwise addition is the completion of the demercuration reaction.
In the present invention, the reaction process of the demercuration reaction is preferably as follows:
after the demercuration reaction is finished, the invention also preferably comprises a post-treatment process, wherein the post-treatment process preferably comprises the steps of separating a water phase, washing by using diethyl ether, distilling under reduced pressure and adding water in sequence; the process of separating the aqueous phase and distilling under reduced pressure is not limited in any way, and can be carried out by adopting a process well known by the technical personnel in the field; in the present invention, the reduced pressure distillation serves to remove diethyl ether. In the present invention, the number of washing with diethyl ether is preferably 3 to 5.
After the reduction type polycarboxylate superplasticizer is obtained, the invention preferably prepares a reduction type polycarboxylate superplasticizer solution by adding water so as to be convenient for subsequent application in concrete. In the present invention, the concentration of the reduction type polycarboxylate superplasticizer solution is preferably 30 to 50 wt%, more preferably 40 wt%.
According to the method, the separated water phase is washed by ether to obtain a target product, a mercury layer generated by reduction can be obtained, mercury with yield over 95% can be recovered without special treatment, and the recovered mercury can be used as a reagent for the next alcoxyl mercurizing reaction after salinization reaction.
The invention also provides a shrinkage-reducing polycarboxylate superplasticizer prepared by the preparation method of the technical scheme, which has a structure shown in formula 1:
wherein R is1Is hydrogen or carboxyl, R2Is hydrogen, methyl or methylenecarboxyl, R3、R4、R6、R7And R9Independently is hydrogen or methyl, R5Is methylene or absent, R8Is methyl, ethyl or isopropyl, R10Is methylene or absent;
the value range of a is 10-30, the value range of b is 5-30, the value range of c is 5-20, and the value range of n is 11-120.
The invention also provides application of the reduction type polycarboxylate superplasticizer in the technical scheme in the field of concrete. In the invention, the mass of the water reducing agent is preferably 0.5-3.0% of the mass of the concrete.
The present invention will be described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.
Example 1
Mixing 1.8g of acrylic acid, 1.93g of hydroxyethyl acrylate, 50g of allyl polyoxyethylene ether (weight-average molecular weight is 3000), 42.98g of water and 0.31g of thioglycolic acid under the stirring condition, heating to 60 ℃, dropwise adding 1.6g of 10 mass percent ammonium persulfate aqueous solution for 2 hours, continuing to perform constant-temperature reaction for 1 hour after dropwise adding is finished, and performing reduced pressure distillation to remove water to obtain a solid copolymerization product;
mixing the solid copolymerization product, 0.08g of mercury acetate, 10.5g of 3-methyl-1-pentene and 300.16g of tetrahydrofuran, heating and refluxing for 6 hours under the condition of stirring, controlling the distillation temperature of a fractionating column to be 35 ℃, and obtaining an evaporated product which is an alkoxy mercurization product;
and (2) dropwise adding 1.63g of sodium borohydride-sodium hydroxide aqueous solution with the mass percentage of 5% (the mass ratio of sodium borohydride to sodium hydroxide is 1:10) into the alcoxyl mercurizing product, stirring, controlling the temperature to be 25 ℃, separating out a water phase after 5h of dropwise addition, washing with 50g of diethyl ether for 4 times, carrying out reduced pressure distillation to remove the diethyl ether, and adding 129.36g of water to obtain the reduction type polycarboxylic acid water reducing agent solution with the mass percentage concentration of 30%.
And (3) storing the shrinkage-reducing polycarboxylate superplasticizer solution with the mass percentage concentration of 30% at 5 ℃ for 30 days, and then measuring the implementation effect.
Example 2
Mixing 8.6g of methacrylic acid, 3.25g of hydroxyethyl methacrylate, 50g of isobutylene polyoxyethylene ether (weight average molecular weight is 1000), 74.22g of water and 3.98g of mercaptopropionic acid under stirring, heating to 70 ℃, dropwise adding 9g of 30 mass percent potassium persulfate aqueous solution for 3 hours, continuing constant-temperature reaction for 4 hours after dropwise adding, and carrying out reduced pressure distillation to remove water to obtain a solid copolymerization product;
mixing the solid copolymerization product, 0.32g of mercury trifluoroacetate, 2.1g of 4-methyl-1-pentene and 121.17g of N, N-dimethylformamide, heating and refluxing for 4 hours under the condition of stirring, controlling the distillation temperature of a fractionating column to be 40 ℃, and obtaining a distilled product which is an alkoxy mercurization product;
0.58g of sodium borohydride-sodium hydroxide aqueous solution with the mass percentage of 20% (the mass ratio of sodium borohydride to sodium hydroxide is 1:5) is dripped into the alcoxyl mercurizing product, the mixture is stirred, the temperature is controlled to be 20 ℃, after 3h dripping, the water phase is separated, 50g of ethyl ether is used for washing for 3 times, reduced pressure distillation is carried out to remove the ethyl ether, 71.07g of water is added, and the reduction type polycarboxylic acid water reducing agent solution with the mass percentage concentration of 50% is obtained.
And (3) storing the shrinkage-reducing polycarboxylate superplasticizer solution with the mass percentage concentration of 50% at 5 ℃ for 20 days, and then measuring the implementation effect.
Example 3
Mixing 9.75g of itaconic acid, 4.88g of hydroxypropyl acrylate, 50g of isopentenyl polyoxyethylene ether (weight average molecular weight is 2000), 64.63g of water and 0.2g of sodium methallyl sulfonate under stirring, heating to 90 ℃, dropwise adding 15.87g of 15 mass percent sodium persulfate aqueous solution for 4 hours, continuing to react for 2 hours at constant temperature after dropwise adding is finished, and carrying out reduced pressure distillation to remove water to obtain a solid copolymerization product;
mixing the solid copolymerization product, 0.06g of mercury acetate, 4.04g of 3-methyl-1-hexene and 149.42g of sulfolane, heating and refluxing for 8 hours under the condition of stirring, controlling the distillation temperature of a fractionating column to be 36 ℃, and obtaining an evaporated product which is an alkoxy mercurization product;
and (2) dropwise adding 0.08g of sodium borohydride-sodium hydroxide aqueous solution with the mass percentage of 30% (the mass ratio of sodium borohydride to sodium hydroxide is 1:6) into the alcoxyl mercurizing product, stirring, controlling the temperature to be 22 ℃, separating out a water phase after 4h of dropwise addition, washing with 150g of diethyl ether for 5 times, carrying out reduced pressure distillation to remove the diethyl ether, and adding 166.45g of water to obtain the shrinkage-reducing polycarboxylic acid water reducing agent solution with the mass percentage of 30%.
And (3) storing the shrinkage-reducing polycarboxylate superplasticizer solution with the mass percentage concentration of 30% at 6 ℃ for 20 days, and then measuring the implementation effect.
Example 4
Mixing 17.4g of maleic acid (anhydride), 28.8g of hydroxypropyl methacrylate, 50g of allyl polyoxyethylene ether (weight average molecular weight is 500), 76.96g of water and 7.2g of sodium allylsulfonate under a stirring condition, heating to 80 ℃, dropwise adding 38g of ammonium persulfate aqueous solution with the mass percentage of 30% for 1h, continuing to react for 5h at constant temperature after dropwise adding is finished, and removing water by reduced pressure distillation to obtain a solid copolymerization product;
mixing the solid copolymerization product, 1.7g of mercury trifluoroacetate, 14.7g of 4-methyl-1-hexene and 187.81g of dimethyl sulfoxide, heating and refluxing for 5 hours under the condition of stirring, controlling the distillation temperature of a fractionating column to be 38 ℃, and obtaining an evaporated product which is an alkoxy mercurization product;
and (2) dropwise adding 10.66g of sodium borohydride-sodium hydroxide aqueous solution with the mass percentage content of 10% (the mass ratio of sodium borohydride to sodium hydroxide is 1:8) into the alcoxyl mercurizing product, stirring, controlling the temperature to be 20 ℃, separating out a water phase after 2h of dropwise addition, washing with 100g of diethyl ether for 5 times, carrying out reduced pressure distillation to remove the diethyl ether, and adding 198.4g of water to obtain the reduction type polycarboxylic acid water reducing agent solution with the mass percentage concentration of 40%.
And (3) storing the reduced polycarboxylate superplasticizer solution with the mass percentage concentration of 40% for 40 days at 6 ℃, and then measuring the implementation effect.
Example 5
Mixing 15.47g of fumaric acid, 3.87g of hydroxyethyl acrylate, 50g of isobutylene polyoxyethylene ether (weight average molecular weight is 1500), 76.27g of water and 2.15g of thioglycolic acid under the stirring condition, heating to 75 ℃, dropwise adding 90g of 1% by mass potassium persulfate aqueous solution for 5 hours, continuing to react for 3 hours at constant temperature after dropwise adding is finished, and distilling under reduced pressure to remove water to obtain a solid copolymerization product;
mixing the solid copolymerization product, 0.11g of mercury acetate, 2.24g of 1-hexene and 240.11g of tetrahydrofuran, heating and refluxing for 10 hours under the condition of stirring, controlling the distillation temperature of a fractionating column to be 40 ℃, and obtaining a distilled product which is an alkoxy mercurization product;
and (2) dropwise adding 0.4g of sodium borohydride-sodium hydroxide aqueous solution with the mass percentage of 15% (the mass ratio of sodium borohydride to sodium hydroxide is 1:7) into the alcoxyl mercurizing product, stirring, controlling the temperature to be 23 ℃, separating out a water phase after 5h of dropwise addition, washing with 150g of diethyl ether for 4 times, carrying out reduced pressure distillation to remove the diethyl ether, and adding 74.8g of water to obtain the shrinkage-reducing polycarboxylic acid water reducing agent solution with the mass percentage concentration of 50%.
And (3) storing the shrinkage-reducing polycarboxylate superplasticizer solution with the mass percentage concentration of 50% at 6 ℃ for 30 days, and then measuring the implementation effect.
Test example
The stored reduction type polycarboxylate superplasticizer solution prepared in the examples 1 to 5 and the non-stored reduction type polycarboxylate superplasticizer prepared in the examples 1 to 5 are subjected to cement paste fluidity tests under different mixing amounts:
according to GB/T8077-2012, the homogeneity test method of concrete admixture is carried out, wherein W/C is 0.29, the mixing amount is the bending mixing amount, the existing common commercially available polycarboxylate superplasticizer (Point-TS 8 polycarboxylate superplasticizer available from Jie New materials Co., Ltd. of Kejie) is used as a comparative example, and the test results are shown in Table 1:
TABLE 1 Cement paste flow Performance results at various loadings
As can be seen from Table 1, the shrinkage-reducing polycarboxylate superplasticizer solution prepared by the method disclosed by the invention has better net slurry fluidity and net slurry fluidity maintaining results under various output conditions, and has better effect than a comparative example.
The concrete slump and the concrete slump of the stored solution of the shrinkage-reducing polycarboxylate superplasticizers prepared in the examples 1 to 5 and the concrete slump of the non-stored shrinkage-reducing polycarboxylate superplasticizers prepared in the examples 1 to 5 are tested:
the test is carried out according to GB/T50080-2002 Standard of Performance test methods for common concrete mixtures, and the test results are shown in Table 2:
TABLE 2 concrete flow Performance results
Note: wherein "-" represents the degree of object spread
As can be seen from Table 2, the solution of the shrinkage-reducing polycarboxylic acid water reducing agent prepared by the invention can show excellent slump, expansion and slump retention capacity with time in a concrete system;
the stored reduction type polycarboxylate water reducer solutions prepared in examples 1 to 5 and the non-stored reduction type polycarboxylate water reducers prepared in examples 1 to 5 were subjected to a test of the reduction effect of concrete:
preparing concrete according to the concrete proportion corresponding to the table 2, wherein the difference is that the shrinkage-reducing polycarboxylic acid water reducing agent is not added in the comparative example 1, and 1.0 percent of DS-J5 shrinkage-reducing polycarboxylic acid water reducing agent purchased from doctor science and technology Limited, Guizhou stone is added in the comparative example 2; the test is carried out according to GB/T50082-2009 Standard test method for the long-term performance and the durability of the common concrete, and the test result is shown in Table 3:
TABLE 3 concrete shrinkage test results
As can be seen from Table 3, the shrinkage-reducing polycarboxylic acid water reducing agent prepared by the invention can remarkably reduce the drying shrinkage of concrete in all ages of 3d, 7d, 14d and 28d, and has more excellent shrinkage reducing effect compared with a comparative example.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The preparation method of the reduction type polycarboxylate superplasticizer is characterized by comprising the following steps:
mixing unsaturated carboxylic acid, unsaturated carboxylic acid hydroxy ester, unsaturated polyoxyethylene ether, water, a molecular weight regulator and an initiator to perform polymerization reaction to obtain a solid copolymerization product;
mixing the solid copolymerization product, mercury salt, lower olefin and an organic solvent to perform an alkoxy mercurization reaction to obtain an alkoxy mercurization product;
dropwise adding sodium borohydride-sodium hydroxide aqueous solution into the alcoxyl mercurizing product to perform demercuration reaction to obtain the reduction type polycarboxylate water reducer
The lower olefin is 3-methyl-1-pentene, 4-methyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene or 1-hexene.
2. The production method according to claim 1, wherein the unsaturated carboxylic acid is acrylic acid, methacrylic acid, itaconic acid, maleic acid, or fumaric acid;
the unsaturated carboxylic hydroxyl ester is hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate;
the unsaturated polyoxyethylene ether is hydroxypropyl polyoxyethylene ether, isobutylene polyoxyethylene ether or isopentenyl polyoxyethylene ether.
3. The production method according to claim 1 or 2, wherein the molar ratio of the unsaturated carboxylic acid, the unsaturated carboxylic acid hydroxy ester and the unsaturated polyoxyethylene ether is (1.5 to 4): (0.5-2): 1.
4. the method according to claim 1, wherein the molecular weight modifier is thioglycolic acid, mercaptopropionic acid, sodium methallylsulfonate, or sodium allylsulfonate;
the initiator is persulfate.
5. The method according to claim 1 or 4, wherein the molar ratio of the molecular weight regulator, the initiator and the unsaturated polyoxyethylene ether is (0.05 to 0.75): (0.05-0.5): 1.
6. the method of claim 1, wherein the mercury salt is mercury acetate or mercury trifluoroacetate;
the molar ratio of the mercury salt to the unsaturated carboxylic acid hydroxy ester is (0.005-0.03): 1;
the molar ratio of the lower olefin to the unsaturated carboxylic acid hydroxy ester is (0.75-1.2): 1.
7. the process according to claim 1 or 6, wherein the alkoxymercurization reaction is carried out by: refluxing for 4-10 h under the condition of stirring;
and controlling the distillation temperature of the fractionating column to be 35-40 ℃ in the reflux process.
8. The preparation method according to claim 1, wherein the total mass percentage of sodium borohydride and sodium hydroxide in the sodium borohydride-sodium hydroxide aqueous solution is 5-30%;
the mass ratio of the sodium hydroxide to the sodium borohydride is 1: (5-10); the molar ratio of the sodium borohydride to the mercury salt is (0.5-0.8): 1.
9. the reduction type polycarboxylate superplasticizer prepared by the preparation method of any one of claims 1 to 8 is characterized by having a structure shown in formula 1:
wherein R is1Is hydrogen or carboxyl, R2Is hydrogen, methyl or methylenecarboxyl, R3、R4、R6、R7And R9Independently is hydrogen or methyl, R5Is methylene or absent, R8Is methyl, ethyl or isopropyl, R10Is methylene or absent;
the value range of a is 10-30, the value range of b is 5-30, the value range of c is 5-20, and the value range of n is 11-120.
10. The use of the reducing polycarboxylate water reducer of claim 9 in the field of concrete.
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| CN110358023A (en) * | 2019-07-31 | 2019-10-22 | 科之杰新材料集团有限公司 | A kind of low surface tension shrinkage type polycarboxylate water-reducer and preparation method thereof |
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