CN114230727B - Shrinkage-reducing ether polycarboxylate superplasticizer and preparation method thereof - Google Patents
Shrinkage-reducing ether polycarboxylate superplasticizer and preparation method 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
- C04B24/2688—Copolymers containing at least three different monomers
- C04B24/2694—Copolymers containing at least three different monomers 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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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
The invention relates to the field of concrete additives, in particular to a shrinkage-reducing ether polycarboxylate superplasticizer and a preparation method thereof. Wherein, a shrinkage-reducing ether polycarboxylate water reducer, its characterized in that: comprises an esterification product, an ether macromonomer, acrylic acid, an unsaturated ester monomer and a functional monomer B; the esterification product is mainly prepared by esterification reaction of functional monomer A and unsaturated acid; the functional monomer A is a monomer with benzene ring, borate and hydroxyl; the functional monomer B is a monomer with double bonds, benzene rings, borate and fluorocarbon bonds. The shrinkage-reducing ether polycarboxylate water reducer provided by the invention can effectively reduce the surface tension of concrete, has better dispersion capability, and can obviously improve the shrinkage-reducing effect of concrete. Meanwhile, the hydration speed of the concrete can be further delayed, shrinkage cracking caused by temperature is prevented, and the concrete has good application prospect and popularization value.
Description
Technical Field
The invention relates to the field of concrete additives, in particular to a shrinkage-reducing ether polycarboxylate superplasticizer and a preparation method thereof.
Background
One of the reasons for cracking of concrete is plastic shrinkage, which causes cracking that affects the service life and practical performance of the concrete. In particular to a concrete member, a bridge and an engineering structure of a high-rise building, and once the engineering structure is cracked, the overall performance of the building is affected. It is therefore necessary to solve the shrinkage cracking problem of high performance concrete. At present, the shrinkage reducing agent, the expanding agent or the fiber is generally adopted at home and abroad to compensate the plastic shrinkage of the concrete, but the doping amount is larger, and the engineering cost is increased. At present, the research focus is on synthesizing a polycarboxylic acid water reducer with a shrinkage reducing function, introducing shrinkage reducing groups from a molecular structure design, and having good shrinkage reducing function and retaining high water reducing rate.
In addition, the early hydration speed of the mass concrete is high, the hydration heat release amount is large, and shrinkage cracking caused by temperature change is easy to occur. Retarder is generally adopted at present to reduce the hydration speed, but the problem of longer setting time of concrete is caused, so that the internal and external shrinkage is inconsistent. Therefore, the water reducer should also properly introduce groups for reducing hydration heat, so as to avoid cracking caused by too fast shrinkage and inconsistent internal and external shrinkage.
The patent document with publication number of CN109467649A and publication date of 2019, 03 and 15 discloses a high-strength concrete shrinkage-reducing polycarboxylate water reducer and a preparation method thereof, wherein maleic anhydride, polyethylene glycol, micromolecular alcohol and phosphorylating agent are subjected to esterification reaction under the action of a catalyst to prepare a functional monomer, and then the functional monomer, polyether macromonomer, unsaturated carboxylic acid, an initiator and a chain transfer agent are subjected to free polymerization reaction to obtain the shrinkage-reducing polycarboxylate water reducer.
The patent document with publication number of CN107868187A and publication date of 2018, 04 and 03 discloses a preparation method of a low hydration heat polycarboxylate water reducer, which is mainly prepared by mixing unsaturated carboxylic acid or unsaturated carboxylic anhydride, alcohol amine, hydroxyphenyl phosphoric acid monomer and polymerization inhibitor, catalyzing and preparing functional monomer under the protection of nitrogen, and carrying out free polymerization reaction with polyether macromonomer, initiator and chain transfer agent to obtain the low hydration heat polycarboxylate water reducer.
Patent document with publication number of CN112979887A and publication day of 2021, month and 18 discloses a modified polycarboxylic acid and a preparation method thereof, wherein a vinyl silane coupling agent and a fluorosilane coupling agent are subjected to hydrolytic polycondensation under an isopropanol solvent and normal temperature to obtain a silane modified monomer, and then a polyether macromonomer, acrylic acid and the silane modified monomer are subjected to polymerization reaction under the action of an initiator to prepare the polycarboxylic acid water reducer with high dispersion slump retaining performance, but the reaction steps are complex, and the effect of reducing shrinkage is not enhanced.
Disclosure of Invention
In order to solve the problems of shrinkage cracking of concrete, high cost of adding a shrinkage reducing agent and an expanding agent, non-coagulation of concrete for a long time and the like of a compound retarder, the invention provides a shrinkage reducing ether polycarboxylate water reducer which comprises an esterification product, an ether macromonomer, acrylic acid, an unsaturated esterification monomer and a functional monomer B;
the esterification product is mainly prepared by esterification reaction of functional monomer A and unsaturated acid; the functional monomer A is a monomer with benzene ring, borate and hydroxyl;
the functional monomer B is a monomer with double bonds, benzene rings, borate and fluorocarbon bonds.
In some embodiments, the functional monomer a has the structural formula:
the functional monomer A is 4-hydroxyphenylboronic acid pinacol ester.
In some embodiments, the preparation process of the esterification product comprises the steps of adding unsaturated acid and functional monomer A into a reaction vessel, mixing, adding a catalyst and a polymerization inhibitor under the condition of nitrogen, adjusting the temperature to 120-135 ℃ and reacting for 4-6 hours to obtain the esterification product.
In some embodiments, the unsaturated acid is one of acrylic acid, methacrylic acid.
In some embodiments, the catalyst is one of cerium sulfate, concentrated sulfuric acid, and p-toluenesulfonic acid
In some embodiments, the polymerization inhibitor comprises one of hydroquinone, diphenylamine, methyl hydroquinone.
In some embodiments, the molar ratio of the functional monomer A to the unsaturated acid is 1:1.5-4, the catalyst is used in an amount of 0.8-2.5% of the total mass of the unsaturated acid and the functional monomer A, and the polymerization inhibitor is used in an amount of 0.5-3% of the total mass of the unsaturated acid and the functional monomer A.
In some embodiments, the functional monomer B is trans-2- [4- (trifluoromethyl) phenyl ] vinylboronic acid.
In some embodiments, the ether macromer is one of 4-hydroxybutyl vinyl ether polyoxyethylene ether, ethylene glycol monovinyl polyoxypropylene ether, methallyl monomethyl ether polyoxyethylene ether, allyl polyoxyethylene polyoxypropylene ether having a molecular weight of 2000-4000.
In some embodiments, the unsaturated ester monomer is one of hydroxyethyl acrylate, methyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate.
In some embodiments, the mass ratio of the esterification product, the ether macromonomer, the acrylic acid, the unsaturated ester monomer and the functional monomer B is 3.5-7:100:4.5-11:2-5.5:0.8-2.
In some embodiments, the composition further comprises an emulsifier, an oxidizing agent, a reducing agent, and a chain transfer agent; the usage amount of the emulsifier is 0.7-2% of the total mass of the ether macromonomer, the usage amount of the oxidant is 0.8-3.2% of the total mass of the ether macromonomer, the usage amount of the reducer is 1-3% of the total mass of the ether macromonomer, and the usage amount of the chain transfer agent is 0.5-2.8% of the total mass of the ether macromonomer.
In some embodiments, the emulsifier is sorbitol polyoxyethylene ether tetraoleate.
In some embodiments, the chain transfer agent is one of 2-hydroxy propanethiol, dithiobenzoic acid ester butyric acid, sodium formate, potassium hypophosphite.
In some embodiments, the oxidizing agent is one of ammonium persulfate, sodium persulfate, hydrogen peroxide, and t-butyl hydroperoxide.
In some embodiments, the reducing agent is one of sodium hypophosphite, ascorbic acid, ferrous sulfate, or disodium 2-hydroxy-2-sulfinylacetate.
The invention also provides a preparation method of the shrinkage-reducing ether polycarboxylate superplasticizer, which comprises the following steps:
adding the esterified product, the ether macromonomer, the functional monomer B and the emulsifier into a reaction vessel for mixing, respectively dripping an oxidant solution, a mixed solution of a reducing agent and a chain transfer agent, and a mixed solution of acrylic acid and an unsaturated ester monomer, reacting for 1-2 h at room temperature, preserving heat for a period of time after the reaction is finished, and adding liquid alkali to adjust the pH to 6-7 to obtain the shrinkage-reducing ether polycarboxylate water reducer.
Preferably, the liquid base is a 32% strength by mass sodium hydroxide solution.
Based on the above, the invention has the following beneficial effects:
1. the invention utilizes 4-hydroxyphenylboronic acid pinacol ester and unsaturated acid to prepare an esterification product, has the advantages of low cost and simple operation, the esterification product contains a mixture prepared by monohydroxy esterification or dihydroxyl esterification, the prepared esterification product participates in the next copolymerization reaction, so that the main chain of the polycarboxylate water reducer is provided with benzene rings, boric acid, hydroxyl groups and other groups, and a rigid benzene ring is introduced into the main chain, so that the main chain has a rigid and inflexible structure, and the molecules of the water reducer are not easy to be buried by stone powder in machine-made sand, thereby improving the workability of concrete; the hydroxyl complex calcium ion has strong capability, enhances the adsorption capability of the water reducer, can continuously combine calcium ions released during cement hydration, and inhibits the hydration of hydrated minerals and the growth of hydration products, thereby greatly delaying the cement hydration process, reducing the hydration heat and finally preventing shrinkage cracking caused by temperature change; meanwhile, the monomer obtained after dihydroxyl esterification also plays a role in crosslinking, and partial crosslinking is realized in the polymerization process, so that the water reducer molecules have long-chain branches, the steric hindrance effect of the system is increased, the capillary effect of the long-chain branches enables a hydration film to be stably wrapped around cement particles, the lubrication effect is realized in the whole mixture system, the water retention effect is further enhanced, and the workability of the machine-made sand concrete is ensured. And under the alkaline condition of cement, the carboxylic acid groups contributing to the water reducing effect are gradually released through gradual hydrolysis along with the extension of time, so that the lost water reducing rate is compensated, and the slump retaining effect is achieved.
2. The esterification product and the trans-2- [4- (trifluoromethyl) phenyl group in the invention]The vinyl boric acid participates in copolymerization reaction, so that the polycarboxylic acid water reducer has a plurality of borate radicals in molecules, the adsorption capacity of the borate radicals is larger than that of static adsorption of carboxyl, the dispersion capacity of the polycarboxylic acid water reducer can be greatly improved, and the adaptability to cement, aggregate impurities and environment is improved, so that the workability of concrete is improved. The benzene ring is introduced, so that the rigid structure of the main chain is further enhanced, the main chain structure can be unfolded, the adsorption area of cement particles is increased, agglomeration is not easy to occur, and the adsorption efficiency is improved. The electronegativity of fluorine is large, and the organic fluorine is introduced to increase the hydrogen bonding degree of polycarboxylic acid molecules, improve the crosslinking degree of molecules, increase the thickness of hydration film and improve the lubricity among particles. At the same time the fluorocarbon reducing group (CF) 3 ) The surface tension of the polycarboxylate water reducer can be obviously reduced, and the polycarboxylate water reducer has a good shrinkage reducing effect.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure and/or components pointed out in the written description and claims.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the following description will be made in conjunction with the technical solutions in the embodiments of the present invention, and it is apparent that the described embodiments are some, but not all, embodiments of the present invention; the technical features designed in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other; all other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs and are not to be construed as limiting the present invention; it will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Example 1
A1, preparing an esterification product: preparation of esterification products: adding 72 parts of acrylic acid and 100 parts of 4-hydroxyphenylboronic acid pinacol ester into a first reaction vessel for mixing, adding 3.6 parts of p-toluenesulfonic acid and 2.8 parts of hydroquinone under the protection of nitrogen, regulating the reaction temperature to 120 ℃, and reacting for 5 hours to obtain an esterification product;
a2, copolymerization reaction: according to weight parts, adding 5 parts of the esterification product prepared in A1, 100 parts of 4-hydroxybutyl vinyl ether polyoxyethylene ether with the molecular weight of 4000, 2 parts of trans-2- [4- (trifluoromethyl) phenyl ] vinyl boric acid, 0.7 part of sorbitol polyoxyethylene ether tetraoleate and 118 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 0.8 part of ammonium persulfate and 20 parts of water into a first dropwise adding device; 3 parts of ferrous sulfate, 1.2 parts of sodium formate and 20 parts of water are uniformly mixed in a second dripping device; 4.5 parts of acrylic acid, 3 parts of hydroxypropyl methacrylate and 20 parts of water are uniformly mixed in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Example 2
B1, preparation of an esterification product: adding 156.3 parts of methacrylic acid and 100 parts of 4-hydroxyphenylboronic acid pinacol ester into a first reaction vessel for mixing, adding 2 parts of concentrated sulfuric acid and 7.7 parts of diphenylamine under the protection of nitrogen, regulating the reaction temperature to 135 ℃, and reacting for 5 hours to obtain an esterification product;
b2, copolymerization reaction: adding 7 parts of the esterified product prepared by the B1, 100 parts of ethylene glycol monovinyl polyoxypropylene ether with the molecular weight of 2400, 1.4 parts of trans-2- [4- (trifluoromethyl) phenyl ] vinyl boric acid, 1.2 parts of sorbitol polyoxyethylene ether tetraoleate and 131 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 1.5 parts of sodium persulfate with 20 parts of water in a first dripping device; 1 part of sodium hypophosphite, 2 parts of 2-hydroxy propyl mercaptan and 20 parts of water are uniformly mixed in a second dripping device; mixing 9 parts of acrylic acid, 5.5 parts of methyl methacrylate and 20 parts of water uniformly in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at normal temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Example 3
C1, preparation of an esterification product: adding 66.4 parts of methacrylic acid and 100 parts of 4-hydroxyphenylboronic acid pinacol ester into a first reaction vessel for mixing, adding 2.3 parts of p-toluenesulfonic acid and 3.5 parts of methyl hydroquinone under the protection of nitrogen, regulating the reaction temperature to 125 ℃, and reacting for 4 hours to obtain an esterification product;
c2, copolymerization reaction: according to weight parts, adding 6 parts of the esterification product prepared by C1, 100 parts of methyl allyl monomethyl ether polyoxyethylene ether with molecular weight of 3000, 0.8 part of trans-2- [4- (trifluoromethyl) phenyl ] vinyl boric acid, 2 parts of sorbitol polyoxyethylene ether tetraoleate and 129 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 2.8 parts of tert-butyl hydroperoxide and 20 parts of water into a first dropwise adding device; 2.6 parts of ascorbic acid, 0.5 part of potassium hypophosphite and 20 parts of water are uniformly mixed in a second dripping device; mixing 11 parts of acrylic acid, 2 parts of hydroxypropyl acrylate and 20 parts of water uniformly in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 2 hours, and reacting at constant temperature for 0.5 hour;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Example 4
D1, preparation of an esterification product: adding 101.4 parts of acrylic acid and 100 parts of 4-hydroxyphenylboronic acid pinacol ester into a first reaction vessel for mixing, adding 5 parts of cerium sulfate and 1 part of hydroquinone under the protection of nitrogen, and regulating the reaction temperature to 130 ℃ for 6 hours to obtain an esterification product;
d2, copolymerization reaction: adding 3.5 parts of the esterification product prepared by D1, 100 parts of allyl polyoxyethylene polyoxypropylene ether with the molecular weight of 2000, 0.9 part of trans-2- [4- (trifluoromethyl) phenyl ] vinyl boric acid, 1.8 parts of sorbitol polyoxyethylene ether tetraoleate and 123 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 3.2 parts of hydrogen peroxide and 20 parts of water into a first dripping device; 1.5 parts of 2-hydroxy-2-sulfinylacetic acid disodium salt, 2.8 parts of dithiobenzoate butyric acid and 20 parts of water are uniformly mixed in a second dripping device; mixing 6 parts of acrylic acid, 4 parts of hydroxyethyl acrylate and 20 parts of water uniformly in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 2 hours, and reacting at constant temperature for 0.5 hour;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Comparative example 1
And (3) selecting a commercial Point-500S polycarboxylate superplasticizer mother solution and an HME-II expanding agent, and adjusting slump after compounding to verify concrete.
Comparative example 2
And (3) selecting commercial Point-500S type polycarboxylate superplasticizer mother liquor and boric acid, and adjusting slump after compounding to verify concrete.
Comparative example 3
E1, preparation of esterification products: adding 72 parts of acrylic acid and 100 parts of 4-hydroxyphenyl phosphoric acid into a first reaction vessel for mixing, adding 3.6 parts of p-toluenesulfonic acid and 2.8 parts of hydroquinone under the protection of nitrogen, regulating the reaction temperature to 120 ℃, and reacting for 5 hours to obtain an esterification product;
e2, copolymerization reaction: according to weight parts, adding 5 parts of the esterified product prepared by E1, 100 parts of 4-hydroxybutyl vinyl ether polyoxyethylene ether with the molecular weight of 4000, 2 parts of trans-2- [4- (trifluoromethyl) phenyl ] vinyl boric acid, 0.7 part of sorbitol polyoxyethylene ether tetraoleate and 118 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 0.8 part of ammonium persulfate and 20 parts of water into a first dropwise adding device; 3 parts of ferrous sulfate, 1.2 parts of sodium formate and 20 parts of water are uniformly mixed in a second dripping device; 4.5 parts of acrylic acid, 3 parts of hydroxypropyl methacrylate and 20 parts of water are uniformly mixed in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Comparative example 4
F1, copolymerization reaction: according to weight parts, firstly adding 100 parts of 4-hydroxybutyl vinyl ether polyoxyethylene ether with molecular weight 4000, 2 parts of trans-2- [4- (trifluoromethyl) phenyl ] vinylboric acid, 0.7 part of sorbitol polyoxyethylene ether tetraoleate and 110 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 0.8 part of ammonium persulfate and 20 parts of water into a first dropwise adding device; 3 parts of ferrous sulfate, 1.2 parts of sodium formate and 20 parts of water are uniformly mixed in a second dripping device; 4.5 parts of acrylic acid, 3 parts of hydroxypropyl methacrylate and 20 parts of water are uniformly mixed in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Comparative example 5
G1, preparation of esterification products: adding 72 parts of acrylic acid and 100 parts of 4-hydroxyphenylboronic acid pinacol ester into a first reaction vessel for mixing, adding 3.6 parts of p-toluenesulfonic acid and 2.8 parts of hydroquinone under the protection of nitrogen, regulating the reaction temperature to 120 ℃, and reacting for 5 hours to obtain an esterification product;
g2, copolymerization reaction: according to weight parts, adding 5 parts of the esterification product prepared by G1, 100 parts of 4-hydroxybutyl vinyl ether polyoxyethylene ether with the molecular weight of 4000, 0.7 part of sorbitol polyoxyethylene ether tetraoleate and 115 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 0.8 part of ammonium persulfate and 20 parts of water in a first dripping device; 3 parts of ferrous sulfate, 1.2 parts of sodium formate and 20 parts of water are uniformly mixed in a second dripping device; 4.5 parts of acrylic acid, 3 parts of hydroxypropyl methacrylate and 20 parts of water are uniformly mixed in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Comparative example 6
H1, preparation of esterification products: adding 72 parts of acrylic acid and 100 parts of 4-hydroxyphenylboronic acid pinacol ester into a first reaction vessel for mixing, adding 3.6 parts of p-toluenesulfonic acid and 2.8 parts of hydroquinone under the protection of nitrogen, regulating the reaction temperature to 120 ℃, and reacting for 5 hours to obtain an esterification product;
h2, copolymerization: according to weight parts, adding 5 parts of an esterification product prepared by H1, 100 parts of 4-hydroxybutyl vinyl ether polyoxyethylene ether with a molecular weight of 4000, 2 parts of trans-BETA-styrene boric acid, 0.7 part of sorbitol polyoxyethylene ether tetraoleate and 118 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 0.8 part of ammonium persulfate and 20 parts of water into a first dropwise adding device; 3 parts of ferrous sulfate, 1.2 parts of sodium formate and 20 parts of water are uniformly mixed in a second dripping device; 4.5 parts of acrylic acid, 3 parts of hydroxypropyl methacrylate and 20 parts of water are uniformly mixed in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Comparative example 7
I1, preparation of an esterification product: adding 72 parts of acrylic acid and 100 parts of 4-hydroxyphenylboronic acid pinacol ester into a first reaction vessel for mixing, adding 3.6 parts of p-toluenesulfonic acid and 2.8 parts of hydroquinone under the protection of nitrogen, regulating the reaction temperature to 120 ℃, and reacting for 5 hours to obtain an esterification product;
and I2, copolymerization reaction: according to parts by weight, adding 5 parts of the esterified product prepared by I1, 100 parts of 4-hydroxybutyl vinyl ether polyoxyethylene ether with the molecular weight of 4000, 2 parts of p-trifluoromethyl styrene, 0.7 part of sorbitol polyoxyethylene ether tetraoleate and 118 parts of water into a second reaction container, uniformly stirring, and uniformly mixing 0.8 part of ammonium persulfate and 20 parts of water into a first dropwise adding device; 3 parts of ferrous sulfate, 1.2 parts of sodium formate and 20 parts of water are uniformly mixed in a second dripping device; 4.5 parts of acrylic acid, 3 parts of hydroxypropyl methacrylate and 20 parts of water are uniformly mixed in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
Comparative example 8
J1, copolymerization reaction: according to weight portion, adding 5 portions of trans-BETA-styrene boric acid, 100 portions of 4-hydroxybutyl vinyl ether polyoxyethylene ether with molecular weight 4000, 2 portions of trans-2- [4- (trifluoromethyl) phenyl ] vinyl boric acid, 0.7 portion of sorbitol polyoxyethylene ether tetraoleate and 118 portions of water into a second reaction container, uniformly stirring, and uniformly mixing 0.8 portion of ammonium persulfate and 20 portions of water into a first dropping device; 3 parts of ferrous sulfate, 1.2 parts of sodium formate and 20 parts of water are uniformly mixed in a second dripping device; 4.5 parts of acrylic acid, 3 parts of hydroxypropyl methacrylate and 20 parts of water are uniformly mixed in a third dripping device; sequentially starting to dropwise add the materials in the first dropwise adding device, the second dropwise adding device and the third dropwise adding device into the second reaction container at room temperature, respectively dropwise adding the materials in the third dropwise adding device, the second dropwise adding device and the first dropwise adding device in 1.5h, and reacting at constant temperature for 0.5h;
and adding 12 parts by weight of sodium hydroxide with the mass concentration of 32% to obtain the shrinkage-reducing ether polycarboxylate superplasticizer with the concentration of 40%.
It should be noted that the specific parameters or some common reagents in the above embodiments are specific embodiments or preferred embodiments under the concept of the present invention, and are not limited thereto; and can be adaptively adjusted by those skilled in the art within the concept and the protection scope of the invention.
In addition, unless otherwise specified, the starting materials employed may also be commercially available products conventionally used in the art or may be prepared by methods conventionally used in the art.
The shrinkage-reducing ether polycarboxylate water reducer synthesized in examples 1 to 4 was compared with the machine-made sand concrete for comparative examples 1 to 8, and the mixing amount of the water reducer in examples 1 to 4 and comparative examples 1 to 8 was adjusted to a slump of 190.+ -.10 mm mixing amount by using conch PO52.5R cement. According to GB 8076-2008 concrete admixture, GB/T50082-2009 common concrete long-term performance and durability test method Standard, GB/T8077-2012 concrete admixture homogeneity test method, and the likeThe test can be performed. The concrete mixing ratio is as follows: 360kg/m of cement 3 803kg/m of machine-made sand 3 982kg/m stone 3 The concrete test results are shown in table 1.
Table 1 results of concrete performance test
As can be seen from the test results of Table 1, each of the properties of examples 1 to 4 was superior to those of comparative examples 1 to 8. The results of examples 1-4 and comparative examples 1-2 show that compared with the prior art in which the water reducer is compounded with the expansion agent and the retarder, the shrinkage-reducing ether polycarboxylic acid water reducer provided by the invention has lower surface tension and shrinkage, and better workability, strength and 2-hour slump retaining effect. Meanwhile, the compression strength of the concrete of the embodiments 1-4 is not reduced, so that the shrinkage-reducing ether polycarboxylate superplasticizer provided by the invention has a very high practical value.
As can be seen from examples 1 to 4 and comparative example 3, the esterified product of the functional monomer A has a better slump retaining effect than 4-hydroxyphenyl phosphoric acid, and is superior to the latter in terms of workability, surface tension and shrinkage.
As can be seen from the combination of examples 1-4 and comparative examples 4-5, the addition of the esterified product and the functional monomer B adopted by the invention has good workability, and the prepared polycarboxylate water reducer has more excellent water-reducing slump-retaining performance, greatly reduced surface tension and shrinkage rate and better shrinkage reducing effect.
Meanwhile, by combining comparative examples 6 to 7, compared with other silane monomers in the prior art, the functional monomer B adopted by the invention has better shrinkage reducing effect, good workability, lower shrinkage rate and surface tension, and better slump retaining effect of the prepared shrinkage-reducing ether polycarboxylic acid water reducer.
As can be seen from examples 1 to 4 and comparative example 8, compared with the water reducer obtained by directly copolymerizing unsaturated phenylboronic acid monomers, the shrinkage-reducing ether polycarboxylic acid water reducer obtained by copolymerizing the esterification product contains more borate, so that the dispersion capacity and concrete workability of the water reducer are greatly improved, and meanwhile, the esterification product is gradually hydrolyzed to continuously release carboxylic acid groups, so that the slump retaining effect is enhanced;
in conclusion, the shrinkage-reducing ether polycarboxylate water reducer provided by the invention can effectively reduce the surface tension of concrete, has better dispersion capability, and can obviously improve the shrinkage-reducing effect of concrete. Meanwhile, the hydration speed of the concrete can be further delayed, shrinkage cracking caused by temperature is prevented, and the concrete has good application prospect and popularization value.
In addition, it should be understood by those skilled in the art that although many problems exist in the prior art, each embodiment or technical solution of the present invention may be modified in only one or several respects, without having to solve all technical problems listed in the prior art or the background art at the same time. Those skilled in the art will understand that nothing in one claim should be taken as a limitation on that claim.
Although terms such as esterification products, ether macromers, acrylic acid, unsaturated ester monomers, functional monomers B, etc. are more used herein, the possibility of using other terms is not excluded. These terms are used merely for convenience in describing and explaining the nature of the invention; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present invention; the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (8)
1. The shrinkage-reducing ether polycarboxylate water reducer is characterized in that: comprises an esterification product, an ether macromonomer, acrylic acid, an unsaturated ester monomer and a functional monomer B;
the esterification product is mainly prepared by esterification reaction of functional monomer A and unsaturated acid;
the functional monomer A is 4-hydroxyphenylboronic acid pinacol ester; the unsaturated acid is one of acrylic acid and methacrylic acid;
the functional monomer B is trans-2- [4- (trifluoromethyl) phenyl ] vinylboric acid.
2. The shrinkage-reducing ether-type polycarboxylate superplasticizer as claimed in claim 1, wherein: the preparation process of the esterification product comprises the steps of adding unsaturated acid and functional monomer A into a reaction vessel for mixing, adding a catalyst and a polymerization inhibitor under the condition of nitrogen, adjusting the temperature to 120-135 ℃ and reacting for 4-6 hours to obtain the esterification product.
3. The shrinkage-reducing ether-type polycarboxylate superplasticizer as claimed in claim 2, wherein: the molar ratio of the functional monomer A to the unsaturated acid is 1:1.5-4, the catalyst is 0.8-2.5% of the total mass of the unsaturated acid and the functional monomer A, and the polymerization inhibitor is 0.5-3% of the total mass of the unsaturated acid and the functional monomer A.
4. The shrinkage-reducing ether-type polycarboxylate superplasticizer as claimed in claim 1, wherein: the ether macromonomer is one of 4-hydroxybutyl vinyl ether polyoxyethylene ether, ethylene glycol monovinyl polyoxypropylene ether, methyl allyl monomethyl ether polyoxyethylene ether and allyl polyoxyethylene polyoxypropylene ether with the molecular weight of 2000-4000.
5. The shrinkage-reducing ether-type polycarboxylate superplasticizer as claimed in claim 1, wherein: the unsaturated ester monomer is one of methyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate.
6. The shrinkage-reducing ether-type polycarboxylate superplasticizer as claimed in claim 1, wherein: the mass ratio of the esterification product to the ether macromonomer to the acrylic acid to the unsaturated ester monomer to the functional monomer B is 3.5-7:100:4.5-11:2-5.5:0.8-2.
7. The shrinkage-reducing ether-type polycarboxylate superplasticizer as claimed in claim 1, wherein: the components also comprise an emulsifier, an oxidant, a reducing agent and a chain transfer agent; the usage amount of the emulsifier is 0.7-2% of the total mass of the ether macromonomer, the usage amount of the oxidant is 0.8-3.2% of the total mass of the ether macromonomer, the usage amount of the reducing agent is 1-3% of the total mass of the ether macromonomer, and the usage amount of the chain transfer agent is 0.5-2.8% of the total mass of the ether macromonomer.
8. A method for preparing the shrinkage-reducing ether polycarboxylate superplasticizer according to claim 7, wherein: the method comprises the following steps:
adding the esterified product, the ether macromonomer, the functional monomer B and the emulsifier into a reaction vessel for mixing, then respectively dripping an oxidant solution, a reducing agent and chain transfer agent mixed solution, and an acrylic acid and unsaturated ester monomer mixed solution at room temperature for reaction, after the reaction is finished, preserving heat, adding liquid alkali for regulating pH, thus obtaining the shrinkage-reducing ether polycarboxylate water reducer.
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| WO2004099099A1 (en) * | 2003-05-09 | 2004-11-18 | Nippon Shokubai Co., Ltd. | Polycarboxylic acid concrete admixture |
| WO2019003905A1 (en) * | 2017-06-30 | 2019-01-03 | 富士フイルム株式会社 | Reflection-preventing film, polarization plate, and image display device |
| CN111320731A (en) * | 2020-03-12 | 2020-06-23 | 浙江建设职业技术学院 | Polycarboxylate superplasticizer based on phenyl hydroxyl block modification |
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| WO2004099099A1 (en) * | 2003-05-09 | 2004-11-18 | Nippon Shokubai Co., Ltd. | Polycarboxylic acid concrete admixture |
| WO2019003905A1 (en) * | 2017-06-30 | 2019-01-03 | 富士フイルム株式会社 | Reflection-preventing film, polarization plate, and image display device |
| CN112708042A (en) * | 2019-11-25 | 2021-04-27 | 科之杰新材料集团有限公司 | Shrinkage-reducing polycarboxylate superplasticizer and preparation method thereof |
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