CN112300337B - Modified polycarboxylic acid water reducing agent and preparation method thereof - Google Patents

Modified polycarboxylic acid water reducing agent and preparation method thereof Download PDF

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CN112300337B
CN112300337B CN201910689079.6A CN201910689079A CN112300337B CN 112300337 B CN112300337 B CN 112300337B CN 201910689079 A CN201910689079 A CN 201910689079A CN 112300337 B CN112300337 B CN 112300337B
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CN112300337A (en
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蒋卓君
郭鑫祺
罗小峰
沈建荣
邓磊
林添兴
郭元强
麻秀星
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Kezhijie New Material Group Guizhou Co ltd
Kezhijie New Material Group Co Ltd
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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
    • 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
    • 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 discloses a modified polycarboxylate superplasticizer and a preparation method thereof, wherein the method comprises the following steps: providing reactants comprising an unsaturated macromonomer, a diketo-containing unsaturated first compound, a polyhedral oligomeric silsesquioxane-containing unsaturated ester second compound, an unsaturated carboxylic acid and/or an unsaturated carboxylic acid anhydride; and carrying out polymerization reaction on the reactants to generate the modified polycarboxylic acid water reducing agent. Through the mode, the modified polycarboxylate superplasticizer with excellent slow-release slump-retaining effect, bleeding resistance effect and reinforcing effect can be obtained.

Description

Modified polycarboxylic acid water reducing agent and preparation method thereof
Technical Field
The invention relates to the technical field of building materials, in particular to a modified polycarboxylate superplasticizer and a preparation method thereof.
Background
The polycarboxylate superplasticizer is the most main additive variety of the ready-mixed concrete due to excellent performance and environmental protection. In recent years, premixed concrete is developed very rapidly, the dosage of the polycarboxylate superplasticizer is increased, but new performance requirements brought by the technical improvement of premixed concrete cannot be met.
With the acceleration of urbanization process and the rise of landmark buildings, high-rise buildings attract more and more attention and attention of people, and ultra-high-rise pumped concrete is an indispensable material in the high-rise buildings. With the continuous development of building technology, super high-rise pumping concrete is popularized in engineering construction and widely applied to various cast-in-place concrete members such as cast-in-place beams, slabs, columns, walls and the like, so that a polycarboxylic acid water reducing agent is required to have excellent slow-release slump retaining capability, and due to the gradual shortage of natural river sand resources, in recent years, desalted sea sand, machine-made sand and the like are used for replacing natural river sand, the desalted sea sand can wash off fine components in the sand in a washing desalting process, so that concrete produced by using the concrete is easy to separate and bleed, the machine-made sand is high in mud and powder content, and the additive with the slow-release slump retaining capability is also required to be used for adjusting the time-lapse loss of the slump of the concrete. In addition, in the production process of high-strength and ultra-high-strength concrete, the strength of the concrete is expected to be further improved by adding the admixture.
However, the current polycarboxylic acid water reducing agents have failed to meet the above requirements.
Disclosure of Invention
The invention mainly solves the technical problem of providing a modified polycarboxylate superplasticizer and a preparation method thereof, and the modified polycarboxylate superplasticizer with excellent slow-release slump-retaining effect, bleeding resistance effect and reinforcing effect can be obtained.
In order to solve the technical problems, the invention adopts a technical scheme that: provides a modified polycarboxylate water reducer, the molecular main chain of the modified polycarboxylate water reducer is linked with cage type silsesquioxane and diketone groups.
Wherein the molecular main chain of the modified polycarboxylate superplasticizer is a polycarboxylate superplasticizer molecular main chain modified by hydroxyalkyl acrylate.
In order to solve the technical problem, the invention adopts another technical scheme that: the preparation method of the modified polycarboxylate superplasticizer comprises the following steps: providing reactants comprising an unsaturated macromonomer, a diketo-containing unsaturated first compound, a polyhedral oligomeric silsesquioxane-containing unsaturated ester second compound, an unsaturated carboxylic acid and/or an unsaturated carboxylic acid anhydride; and carrying out polymerization reaction on the reactants to generate the modified polycarboxylic acid water reducing agent.
Wherein the reactants further comprise a hydroxyalkyl acrylate; the method for generating the modified polycarboxylate superplasticizer by carrying out polymerization reaction on the reactants comprises the following steps: the reactants are subjected to polymerization reaction under the action of an initiator and a molecular weight regulator to generate a modified polycarboxylic acid water reducer; wherein the method further comprises: and adjusting the pH value of the modified polycarboxylic acid water reducing agent to 5-7.
Wherein, the reactants are subjected to polymerization reaction under the action of an initiator and a molecular weight regulator to generate the modified polycarboxylic acid water reducer, and the method comprises the following steps: providing an aqueous solution of the unsaturated macromonomer, adding the first compound and the second compound under the condition of a preset reaction temperature range, and uniformly dispersing the first compound and the second compound in a preset rotating speed range to obtain a first mixed reaction system; and (2) dropwise adding an unsaturated carboxylic acid and/or unsaturated carboxylic anhydride aqueous solution, a hydroxyalkyl acrylate aqueous solution, an initiator aqueous solution and a molecular weight regulator aqueous solution into the first mixed reaction system, and preserving heat for a preset time range after dropwise adding to generate the modified polycarboxylic acid water reducing agent.
Wherein the predetermined reaction temperature range is 0-90 ℃; the predetermined rotating speed range is 320-480 r/min; the dripping time range is 0.2-6 h; the preset time range of heat preservation is 0-3 h; wherein the molar ratio of the unsaturated macromonomer, the first compound, the second compound, the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride, and the hydroxyalkyl acrylate is in the range of 5: (2-3): (1-2): (3-10): (6-12); wherein the using amount of the initiator is 0.5-3.0% of the total mass of the reactants; the dosage of the molecular weight regulator is 0.2-3.0% of the total mass of the reactants.
Wherein the first compound has a structural formula:
Figure BDA0002147308970000021
wherein R is1Is H or CH3，R2Is empty or alkyl of 1-4 carbons, R3Is alkyl of 1 to 4 carbons, R4Is alkyl of 1-4 carbons.
Wherein the structural formula of the second compound is:
Figure BDA0002147308970000031
wherein R is5Is alkyl of 1-4 carbons or carboxyl of 1-4 carbons, R6Is alkyl of 1-4 carbons.
Wherein the molecular weight of the unsaturated macromonomer is 600-5000, and the unsaturated macromonomer is at least one of methoxy polyethylene glycol methacrylate, methoxy polyethylene glycol acrylate, methoxy polyethylene glycol maleic acid monoester, 4-hydroxybutyl vinyl polyoxyethylene ether, allyl polyethylene glycol, 3-methyl-3-butylene-1-polyethylene glycol and 2-methylallyl polyethylene glycol; wherein the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride is at least one of acrylic acid, methacrylic acid and maleic anhydride.
Wherein, the hydroxyalkyl acrylate is at least one of hydroxyethyl acrylate and hydroxypropyl acrylate; wherein the initiator is at least one of a water-soluble redox initiation system, a water-soluble peroxide initiator and a water-soluble azo initiator; wherein the molecular weight regulator is at least one of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol and sodium hypophosphite.
The invention has the beneficial effects that: different from the situation of the prior art, the modified polycarboxylate water reducer is obtained by introducing a cage-type silsesquioxane and diketone structure into a product molecular structure in a way of copolymerizing unsaturated carboxylic acid (anhydride), hydroxyalkyl acrylate, a first compound, a second compound and an unsaturated macromonomer, and has excellent initial water reducing effect due to the steric hindrance effect of the cage-type silsesquioxane at the initial stage of adding the modified polycarboxylate water reducer into concrete; the diketone structure in the molecular structure can form a large amount of hydrogen bonds with water molecules in a system, so that the water-resistant paint has an excellent anti-bleeding effect; the introduced cage-type silsesquioxane and the main chain of the product molecule are linked through ester groups, and the ester groups can be gradually hydrolyzed under the concrete alkaline condition, so that the nano-scale cage-type silsesquioxane and carboxylic acid groups with a water reducing effect are released, the nano-scale cage-type silsesquioxane can be filled into gaps in the concrete, and the strength of the concrete is improved; the released carboxylic acid groups and hydroxyalkyl ester in the molecular structure perform water explanation on the released carboxylic acid groups under the concrete alkaline condition to realize excellent slow-release slump retaining performance.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:
FIG. 1 is a schematic flow chart of an embodiment of the preparation method of the modified polycarboxylic acid water reducing agent of the present invention;
FIG. 2 is a schematic flow chart of another embodiment of the method for preparing the modified polycarboxylic acid water reducing agent according to the invention;
FIG. 3 is a schematic flow chart of a further embodiment of the method for preparing a modified polycarboxylic acid water reducing agent according to the present invention;
FIG. 4 is a schematic flow chart of a process for preparing a modified polycarboxylic acid water reducing agent according to yet another embodiment of the present invention;
FIG. 5 is a schematic flow chart of a further embodiment of the method for preparing a modified polycarboxylic acid water reducing agent according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a preparation method of a modified polycarboxylic acid water reducer of the present invention, and the method includes:
step S101: reactants are provided, the reactants include an unsaturated macromonomer, a diketonate-containing unsaturated first compound, a polyhedral oligomeric silsesquioxane-containing unsaturated ester second compound, an unsaturated carboxylic acid and/or an unsaturated carboxylic acid anhydride.
The polycarboxylate water reducing agent is a high molecular polymer with amphiphilic property, and generally adopts an unsaturated macromonomer with a terminal unsaturated bond (such as a carbon-carbon double bond) and an unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride micromolecule monomer to perform copolymerization reaction under the action of an initiator, wherein the terminal unsaturated group (such as a terminal alkenyl group) of the large monomer and the terminal unsaturated group of the small monomer form a molecular main chain through copolymerization.
In the present embodiment, the unsaturated macromonomer, i.e., the polycarboxylic acid water reducing agent unsaturated macromonomer, is a long-chain monomer having an unsaturated bond (the unsaturated bond is usually at the end, and the unsaturated bond is usually a carbon-carbon double bond) and capable of undergoing a polymerization reaction, relative to the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride small-molecule monomer.
In one embodiment, the molecular weight of the unsaturated macromonomer is 600-: unsaturated ether macromonomers, unsaturated ester macromonomers, and the like.
Unsaturated ether macromonomer is a mainstream macromonomer product at present, and the macromonomer is mainly synthesized into polyethylene glycol ether with terminal group double bonds by ethoxylation reaction of micromolecule unsaturated alcohol initiators with different structures. According to the difference of the molecular structure of the initiator, the synthesized unsaturated macromonomers can be divided into three types: vinyl alcohol 3-carbon macromonomer (allyl polyethylene glycol ether-APEG), vinyl alcohol 4-carbon and 5-carbon macromonomer (isobutenyl polyethylene glycol ether-HPEG, isopentenyl polyethylene glycol ether-TPEG), and vinyl ether 2+2 and 2+4 type macromonomer (EPEG, VPEG).
Specifically, the unsaturated macromonomer can be at least one of methoxy polyethylene glycol methacrylate, methoxy polyethylene glycol acrylate, methoxy polyethylene glycol maleic acid monoester, 4-hydroxybutyl vinyl polyoxyethylene ether, allyl polyethylene glycol, 3-methyl-3-butene-1-polyethylene glycol, and 2-methallyl polyethylene glycol.
Wherein, the unsaturated carboxylic acid and/or the unsaturated carboxylic acid anhydride are unsaturated micromolecule monomers of the polycarboxylate water reducing agent, and in the copolymerization reaction for generating the polycarboxylate water reducing agent, the unsaturated micromolecule monomers can be single unsaturated carboxylic acid, single unsaturated carboxylic acid anhydride or a mixture of the unsaturated carboxylic acid and the unsaturated carboxylic acid anhydride. In one embodiment, the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride may be at least one of acrylic acid, methacrylic acid, and maleic anhydride.
Referring to fig. 2, in one embodiment, the reactants further comprise a hydroxyalkyl acrylate.
That is, step S101 specifically includes: providing reactants comprising an unsaturated macromonomer, a diketone group-containing unsaturated first compound, a polyhedral oligomeric silsesquioxane group-containing unsaturated ester second compound, an unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride and hydroxyalkyl acrylate.
The hydroxyalkyl acrylate is added into the molecular structure of the modified polycarboxylate superplasticizer, so that the sensitivity of the modified polycarboxylate superplasticizer to mud can be reduced, and the mud resistance can be improved. In one embodiment, the hydroxyalkyl acrylate is at least one of hydroxyethyl acrylate and hydroxypropyl acrylate.
The diketone group-containing unsaturated first compound means a compound having a diketone group and an unsaturated bond. The unsaturated bond is used for linking the first compound to the molecular structure of the modified polycarboxylate water reducer, and the diketone is used for modifying the polycarboxylate water reducer, so that the modified polycarboxylate water reducer has a diketone structure which can form a large amount of hydrogen bonds with water molecules in a concrete system, and the modified polycarboxylate water reducer has an excellent bleeding resistance effect.
Wherein the structural formula of the first compound is:
Figure BDA0002147308970000061
wherein R is1Is H or CH3，R2Is empty or alkyl of 1-4 carbons, R3Is alkyl of 1 to 4 carbons, R4Is alkyl of 1-4 carbons.
The unsaturated ester second compound containing a cage-type silsesquioxane group means a compound having a cage-type silsesquioxane group, an unsaturated bond, and an ester group. The unsaturated bond is used for linking a second compound to a molecular structure of the modified polycarboxylate water reducer, the cage-type silsesquioxane group and the ester group are used for modifying the polycarboxylate water reducer, so that the modified polycarboxylate water reducer has the cage-type silsesquioxane group and the ester group, the ester group is gradually hydrolyzed under the concrete alkaline condition, and thus the nano-scale cage-type silsesquioxane and the carboxylic acid group with the water reducing effect are released, the nano-scale cage-type silsesquioxane can fill gaps in concrete, and the strength of the concrete is improved; the released carboxylic acid groups and hydroxyalkyl ester in the molecular structure perform water explanation on the released carboxylic acid groups under the concrete alkaline condition to realize excellent slow-release slump retaining performance.
Wherein the structural formula of the second compound is:
Figure BDA0002147308970000062
wherein R is5Is alkyl of 1-4 carbons or carboxyl of 1-4 carbons, R6Is alkyl of 1-4 carbons.
Step S102: so that the reactants are subjected to polymerization reaction to generate the modified polycarboxylic acid water reducing agent.
According to the embodiment of the invention, a cage-type silsesquioxane and diketone structure is introduced into a product molecular structure by means of copolymerization of unsaturated carboxylic acid (anhydride), hydroxyalkyl acrylate, a first compound, a second compound and an unsaturated macromonomer to obtain a modified polycarboxylate water reducer, and the modified polycarboxylate water reducer has an excellent initial water reducing effect at the initial stage of adding the modified polycarboxylate water reducer into concrete due to the steric hindrance effect of the cage-type silsesquioxane; the diketone structure in the molecular structure can form a large amount of hydrogen bonds with water molecules in a system, so that the water-resistant paint has an excellent anti-bleeding effect; the introduced cage-type silsesquioxane and the main chain of the product molecule are linked through ester groups, and the ester groups can be gradually hydrolyzed under the concrete alkaline condition, so that the nano-scale cage-type silsesquioxane and carboxylic acid groups with a water reducing effect are released, the nano-scale cage-type silsesquioxane can be filled into gaps in the concrete, and the strength of the concrete is improved; the released carboxylic acid groups and hydroxyalkyl ester in the molecular structure perform water explanation on the released carboxylic acid groups under the concrete alkaline condition to realize excellent slow-release slump retaining performance.
Referring to fig. 3, step S102 may specifically include: the reactants are subjected to polymerization reaction under the action of an initiator and a molecular weight regulator to generate the modified polycarboxylic acid water reducing agent.
The initiator, also called as free radical initiator, refers to a kind of compound which is easy to be decomposed into free radicals (i.e. primary free radicals) by heating, and can be used for initiating free radical polymerization and copolymerization of alkene and diene monomers, and also can be used for crosslinking curing and macromolecule crosslinking reaction of unsaturated polyester. The initiator is widely classified into a peroxide initiator, an azo initiator, a redox initiator and the like, and the peroxide initiator is classified into an organic peroxide initiator and an inorganic peroxide initiator. In one embodiment, the initiator is at least one of a water-soluble redox initiation system, a water-soluble peroxide initiator, and a water-soluble azo initiator.
The molecular weight regulator is a substance capable of controlling the molecular weight of the polymer and reducing the branching of polymer chains, and is characterized by large chain transfer constant, so that the molecular weight of the polymer can be effectively reduced by using a small amount, thereby being beneficial to the post-processing and application of the polymer. It is widely used in radical polymerization, and has many kinds of aliphatic thiols, xanthogen disulfides, polyphenol, sulfur, halides, nitroso compounds, etc. In one embodiment, the molecular weight regulator is at least one of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol, and sodium hypophosphite.
Referring to fig. 4, the method further includes:
step S103: and adjusting the pH value of the modified polycarboxylic acid water reducing agent to 5-7.
The pH value of the modified polycarboxylate superplasticizer is adjusted to 5-7, so that the corrosion to production equipment due to too low or too low pH value can be avoided, the dangerous hidden danger to production and use personnel can be avoided, and the influence on the product color due to the pH value higher than 7 can be avoided.
Referring to fig. 5, in step S102, the reactants are subjected to a polymerization reaction under the action of the initiator and the molecular weight regulator to generate the modified polycarboxylic acid water reducer, which may specifically include: substep S1021 and substep S1022.
Substep S1021: providing an aqueous solution of unsaturated macromonomer, adding a first compound and a second compound under the condition of a preset reaction temperature range, and uniformly dispersing the first compound and the second compound in a preset rotating speed range to obtain a first mixed reaction system.
Substep S1022: and (3) dropwise adding an unsaturated carboxylic acid and/or unsaturated carboxylic anhydride aqueous solution, a hydroxyalkyl acrylate aqueous solution, an initiator aqueous solution and a molecular weight regulator aqueous solution into the first mixed reaction system, and preserving heat for a preset time range after dropwise adding to generate the modified polycarboxylic acid water reducing agent.
Wherein the predetermined reaction temperature range is 0-90 ℃, for example: 0 ℃, 30 ℃, 60 ℃, 90 ℃, and the like; the predetermined speed range is 320-: 320r/min, 400r/min, 480r/min, etc.; the dropping time ranges from 0.2 to 6h, for example: 0.2h, 1h, 3h, 5h, 6h, etc.; the predetermined time range of the heat preservation is 0 to 3h, for example: 0h, 1h, 2h, 3h, etc.
Wherein the molar ratio of the unsaturated macromonomer, the first compound, the second compound, the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride and hydroxyalkyl acrylate is in the range of 5: (2-3): (1-2): (3-10): (6-12), for example: the molar ratio of the unsaturated macromonomer, the first compound, the second compound, the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride and hydroxyalkyl acrylate is 5: 2: 1: 3: 6. or 5: 2.5: 1.5: 6.5: 9. or 5: 3: 2: 10: 12, and so on.
Wherein the amount of the initiator is 0.5-3.0% of the total mass of the reactants, such as: 0.5%, 1.0%, 2.0%, 3.0%, etc.; the molecular weight regulator is used in an amount of 0.2 to 3.0% by mass of the total mass of the reactants, for example: 0.2%, 1.0%, 2.0%, 3.0%, etc.
The invention also provides a modified polycarboxylate superplasticizer, the molecular main chain of which is linked with cage-type silsesquioxane and diketone groups.
In one embodiment, the molecular backbone of the modified polycarboxylate water reducer is a hydroxyalkyl acrylate modified polycarboxylate water reducer molecular backbone.
Specifically, the modified polycarboxylate superplasticizer of the embodiment of the invention can be prepared by the above preparation method of the modified polycarboxylate superplasticizer, and for detailed description of relevant contents, refer to the above method section, which is not described in detail herein.
The preparation of the examples of the invention is further illustrated and described below by means of specific examples.
Example 1:
(1) 180.00g of 3-methyl-3-butene-1-polyethyleneglycol having a molecular weight of 2400 and 150.00g of water were added to the reactor, the stirrer and the temperature control device were turned on, and 5.40g of 3-allylpentane-2, 4-dione and 15.00g of 15.00gMA0701 (MA 0701-AcryloIsobutyl from Hybrid Plastics Co.) were added until the 3-methyl-3-butene-1-polyethyleneglycol had completely dissolved
Figure BDA0002147308970000091
) Adjusting the rotating speed of the stirrer to 320r/min, after the 3-allyl pentane-2, 4-dione and MA0701 are uniformly dispersed, starting to dropwise add an acrylic acid aqueous solution (wherein 8.00g of acrylic acid and 20.00g of water), a hydroxyethyl acrylate aqueous solution (wherein 20.00g of hydroxyethyl acrylate and 20.00g of water), a hydrogen peroxide aqueous solution (wherein 1.50g of hydrogen peroxide and 20.00g of water), a mercaptopropionic acid aqueous solution (wherein 0.80g of mercaptopropionic acid and 20.00g of water) and an ascorbic acid aqueous solution (wherein 0.40 g of ascorbic acid and 20.00g of water), wherein the reaction temperature is 30 ℃, the dropwise adding time is 3.0h, and after the dropwise adding is finished, keeping the temperature for 0.5h to obtain a copolymerization product;
(2) and (2) adjusting the pH of the copolymerization product prepared in the step (1) to 5-7 by using alkali to obtain the modified polycarboxylic acid water reducer KZJ-1.
Example 2:
(1) 110.00g of methoxypolyethylene glycol methacrylate having a molecular weight of 1200 and 150.00g of water are introduced into the reactor, the stirrer and the temperature control device are switched on, 5.00g of 3-vinyl pentane-2, 4-dione and 20.00gMA0702 (MA 0702-methacryloyl, Hybrid Plastics) are added after all methoxypolyethylene glycol methacrylate has dissolved
Figure BDA0002147308970000092
) Adjusting the rotating speed of the stirrer to 360r/min, after the 3-vinyl pentane-2, 4-dione and MA0702 are uniformly dispersed, beginning to dropwise add a methacrylic acid aqueous solution (11.00 g of methacrylic acid and 20.00g of water), a hydroxyethyl acrylate aqueous solution (22.00 g of hydroxyethyl acrylate and 20.00g of water), a hydrogen peroxide aqueous solution (2.00 g of hydrogen peroxide and 20.00g of water), a sodium hypophosphite aqueous solution (1.20 g of sodium hypophosphite and 20.00g of water) and an ascorbic acid aqueous solution (0.40 of ascorbic acid and 20.00g of water), wherein the reaction temperature is 60 ℃, the dropwise adding time is 4.0h, and after the dropwise adding is finished, preserving the temperature for 1.0h to obtain a copolymerization product;
(2) and (2) adjusting the pH of the copolymerization product prepared in the step (1) to 5-7 by using alkali to obtain the modified polycarboxylic acid water reducer KZJ-2.
Example 3:
(1) will 140.00g of 4-hydroxybutyl vinyl polyoxyethylene ether having a molecular weight of 3000 and 150.00g of water were added to the reactor, the stirrer and the temperature control device were switched on, and 3.10g of 3-alkenylbutylpentane-2, 4-dione and 13.00gMA0717 (MA 0717-Methylcylethyl of Hybrid Plastics, Inc.) were added until the 4-hydroxybutyl vinyl polyoxyethylene ether was completely dissolved
Figure BDA0002147308970000093
) Adjusting the rotating speed of a stirrer to 400r/min, after uniformly dispersing 3-alkene butyl pentane-2, 4-diketone and MA0717, beginning to dropwise add a maleic anhydride aqueous solution (wherein the maleic anhydride is 6.50g, and the water is 20.00g), a hydroxyethyl acrylate and hydroxypropyl acrylate mixture aqueous solution (wherein the hydroxyethyl acrylate is 8.00g, the hydroxypropyl acrylate is 5.00g, and the water is 20.00g), a hydrogen peroxide aqueous solution (wherein the hydrogen peroxide is 1.20g, and the water is 20.00g), a rongalite aqueous solution (wherein the rongalite is 0.60g, and the water is 20.00g), a ferrous sulfate solution (wherein the ferrous sulfate is 0.50g, and the water is 10.00g), a mercaptopropionic acid aqueous solution (wherein the mercaptopropionic acid is 2.00g, and the water is 20.00g), the reaction temperature is 10 ℃, the dropwise adding time is 0.5h, and after dropwise adding, preserving the temperature for 1.0h, so as to obtain a copolymerization product;
(2) and (2) adjusting the pH of the copolymerization product prepared in the step (1) to 5-7 by using alkali to obtain the modified polycarboxylic acid water reducer KZJ-3.
Example 4:
(1) 100.00g of 3-methyl-3-butene-1-polyethyleneglycol having a molecular weight of 2400, 50.00g of 2-methylallyl-polyethyleneglycol having a molecular weight of 2400 and 150.00g of water were charged into a reactor, and after the 3-methyl-3-butene-1-polyethyleneglycol and the 2-methylallyl-polyethyleneglycol were completely dissolved, 6.00g of 4-allyl-n-heptane-3, 5-dione and 19.00gMA0701 (MA 0701-AcryloIsobutyl of Hybrid Plastics Co.) were added
Figure BDA0002147308970000101
) Adjusting the rotating speed of the stirrer to 400r/min, after the 4-allyl n-heptane-3, 5-diketone and MA0701 are uniformly dispersed, dropwise adding an acrylic acid aqueous solution (5.80 g of acrylic acid and 20.00g of water), a hydroxyethyl acrylate aqueous solution (17.00 g of hydroxyethyl acrylate and 20.00g of water) and a hydrogen peroxide aqueous solution(wherein, 2.00g of hydrogen peroxide and 20.00g of water), mercaptoethanol aqueous solution (wherein, 1.00g of mercaptoethanol and 20.00g of water) and ascorbic acid aqueous solution (wherein, 0.50g of ascorbic acid and 20.00g of water) are reacted at the temperature of 40 ℃, the dripping time is 2.5h, and the temperature is kept for 1.5h after the dripping is finished, so as to obtain a copolymerization product;
(2) and (2) adjusting the pH of the copolymerization product prepared in the step (1) to 5-7 by using alkali to obtain the modified polycarboxylic acid water reducer KZJ-4.
Example 5:
(1) 140.00g of 3-methyl-3-butene-1-polyethylene glycol having a molecular weight of 2400, 50.00g of methoxypolyethylene glycol methacrylate having a molecular weight of 2000 and 150.00g of water were added to the reactor, the stirrer and the temperature control device were started, and 5.00g of 3-allylpentane-2, 4-dione and 21.00gMA0702 (MA 0702-Methylcryloisobutyl, Hybrid Plastics) were added after 3-methyl-3-butene-1-polyethylene glycol and methoxypolyethylene glycol methacrylate had all dissolved
Figure BDA0002147308970000102
) Adjusting the rotating speed of a stirrer to 450r/min, after the 3-allyl pentane-2, 4-dione and MA0702 are uniformly dispersed, beginning to dropwise add a mixture water solution of acrylic acid and methacrylic acid (wherein 5.00g of acrylic acid, 2.00g of methacrylic acid and 20.00g of water), a hydroxyethyl acrylate water solution (wherein 16.00g of hydroxyethyl acrylate and 20.00g of water), a hydrogen peroxide water solution (wherein 2.50g of hydrogen peroxide and 20.00g of water), a mercaptopropionic acid water solution (wherein 1.40g of mercaptopropionic acid and 20.00g of water), an ascorbic acid water solution (wherein 0.60g of ascorbic acid and 20.00g of water), wherein the reaction temperature is 50 ℃, the dropwise adding time is 3.5 hours, and keeping the temperature for 0.5 hour after the dropwise adding is finished to obtain a copolymerization product;
(2) and (2) adjusting the pH of the copolymerization product prepared in the step (1) to 5-7 by using alkali to obtain the modified polycarboxylic acid water reducer KZJ-5.
Comparative example 1:
(1) adding 180.00g of 3-methyl-3-butene-1-polyethylene glycol with the molecular weight of 2400 and 150.00g of water into a reactor, starting a stirrer and a temperature control device, adding 5.40g of 3-allylpentane-2, 4-dione into the reactor when the 3-methyl-3-butene-1-polyethylene glycol is completely dissolved, adjusting the rotating speed of the stirrer to 320r/min, and after the 3-allylpentane-2, 4-dione is uniformly dispersed, beginning to dropwise add an acrylic acid aqueous solution (9.16 g of acrylic acid and 20.00g of water), a hydroxyethyl acrylate aqueous solution (20.00 g of hydroxyethyl acrylate and 20.00g of water), a hydrogen peroxide aqueous solution (1.50 g of hydrogen peroxide and 20.00g of water), a mercaptopropionic acid aqueous solution (0.80 g of mercaptopropionic acid and 20.00g of water), an ascorbic acid aqueous solution (wherein, 0.40 g of ascorbic acid and 20.00g of water), the reaction temperature is 30 ℃, the dripping time is 3.0h, and the temperature is kept for 0.5h after the dripping is finished, so as to obtain a copolymerization product;
(2) and (3) adjusting the pH of the copolymerization product prepared in the step (1) to 5-7 by using alkali to obtain a comparison sample PCE-1.
Comparative example 2:
(1) 180.00g of 3-methyl-3-butene-1-polyethyleneglycol having a molecular weight of 2400 and 150.00g of water were added to the reactor, the stirrer and the temperature control device were started, and 15.00gMA0701 (MA 0701-AcryloIsobutyl from Hybrid Plastics) was added after the 3-methyl-3-butene-1-polyethyleneglycol had completely dissolved
Figure BDA0002147308970000111
) Adjusting the rotating speed of the stirrer to 320r/min, after MA0701 is uniformly dispersed, beginning to dropwise add an acrylic acid aqueous solution (wherein 10.78g of acrylic acid and 20.00g of water), a hydroxyethyl acrylate aqueous solution (wherein 20.00g of hydroxyethyl acrylate and 20.00g of water), a hydrogen peroxide aqueous solution (wherein 1.50g of hydrogen peroxide and 20.00g of water), a mercaptopropionic acid aqueous solution (wherein 0.80g of mercaptopropionic acid and 20.00g of water) and an ascorbic acid aqueous solution (wherein 0.40 g of ascorbic acid and 20.00g of water), wherein the reaction temperature is 30 ℃, the dropwise adding time is 3.0h, and after the dropwise adding is finished, keeping the temperature for 0.5h to obtain a copolymerization product;
(2) and (2) adjusting the pH of the copolymerization product prepared in the step (1) to 5-7 by using alkali to obtain a comparison sample PCE-2.
The modified polycarboxylic acid water reducing agents prepared in examples 1 to 5 and the polycarboxylic acid water reducing agents prepared in comparative examples 1 and 2 were subjected to a performance test according to GB/T8076-2008 according to a folding mixing amount of 0.22%, and the test results are shown in Table 1:
TABLE 1 test results for different water reducing agents
Figure BDA0002147308970000121
The comparison result of the PCE-1 and the KZJ-1 shows that the water reducing rate of the PCE-1 prepared by converting MA0701 in the KZJ-1 into acrylic acid in an equimolar way is lower than that of the KZJ-1, the compressive strength ratio of 1d, 3d, 7d and 28d is also lower than that of the KZJ-1, and the bleeding rate ratio is almost the same as that of the KZJ-1. The comparison result of the PCE-2 and the KZJ-1 shows that the water reducing rate, the 1d, 3d, 7d and 28d compressive strength ratio and the KZJ-1 of the PCE-2 prepared by converting 3-allyl pentane-2, 4-diketone in the KZJ-1 into acrylic acid in the same mole are not different, but the bleeding rate ratio is obviously higher than that of the KZJ-1. In addition, the water reducing rates of KZJ-1 to KZJ-5 are all higher than 30%, the compressive strength ratios of 1d are all higher than 250%, the compressive strength ratios of 3d are all higher than 220%, the compressive strength ratios of 7d are all higher than 200%, the compressive strength ratios of 28d are all higher than 190%, and the bleeding rate ratios are all lower than 5%.
Adopting Fufu P.O 42.5.5 common Portland cement, and the concrete mixing ratio is as follows: cement 300kg/m3100kg/m of fly ash3100kg/m of mineral powder3690kg/m of sand31050kg/m of stones3160kg/m of water3The modified polycarboxylic acid water reducing agents obtained in examples 1 to 5 and the polycarboxylic acid water reducing agents obtained in comparative examples 1 and 2 were subjected to a performance test in terms of the folding blending amount of 0.18%. The initial, 1h, 2h, 3h slump (TL) and slump (TK) of the concrete were tested and the test results for the different water reducers are shown in Table 2.
TABLE 2 test results for different water reducing agents
Figure BDA0002147308970000122
Figure BDA0002147308970000131
As can be seen from the above results, the comparison of PCE-1 with KZJ-1 shows that PCE-1 prepared by equimolar conversion of MA0701 in KZJ-1 to acrylic acid has inferior initial dispersion effect and slump retaining effect to KZJ-1. The result of the comparison between PCE-2 and KZJ-1 shows that the initial dispersion effect of PCE-2 prepared by equimolar changing 3-allyl pentane-2, 4-diketone in KZJ-1 into acrylic acid is higher than that of KZJ-1, but the slump retaining effect is not as good as that of KZJ-1. In addition, KZJ-2 to KZJ-5 have better initial dispersion effect and slump retaining effect.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (8)

1. The modified polycarboxylate water reducer is characterized in that raw materials for preparing the modified polycarboxylate water reducer comprise unsaturated first compounds containing diketone groups and unsaturated ester second compounds containing cage-type silsesquioxane groups, the molecular main chain of the modified polycarboxylate water reducer is linked with the cage-type silsesquioxane groups and the diketone groups,
the first compound has the structural formula:
Figure FDA0003532426950000011
wherein R is1Is H or CH3，R2Is empty or alkyl of 1-4 carbons, R3Is alkyl of 1 to 4 carbons, R4Is an alkyl group of 1 to 4 carbons,
the structural formula of the second compound is:
Figure FDA0003532426950000012
wherein R is5Is alkyl of 1-4 carbons or carboxyl of 1-4 carbons, R6Is alkyl of 1-4 carbons.
2. The modified polycarboxylate water reducer of claim 1, characterized in that the molecular backbone of the modified polycarboxylate water reducer is a hydroxyalkyl acrylate modified polycarboxylate water reducer molecular backbone.
3. A preparation method of a modified polycarboxylate superplasticizer is characterized by comprising the following steps:
providing reactants comprising an unsaturated macromonomer, a diketo-containing unsaturated first compound, a polyhedral oligomeric silsesquioxane-containing unsaturated ester second compound, an unsaturated carboxylic acid and/or an unsaturated carboxylic acid anhydride;
carrying out polymerization reaction on the reactants to generate a modified polycarboxylic acid water reducing agent;
the first compound has the structural formula:
Figure FDA0003532426950000021
wherein R is1Is H or CH3，R2Is empty or alkyl of 1-4 carbons, R3Is alkyl of 1 to 4 carbons, R4Is an alkyl group of 1 to 4 carbons,
the structural formula of the second compound is:
Figure FDA0003532426950000022
wherein R is5Is alkyl of 1-4 carbons or carboxyl of 1-4 carbons, R6Is alkyl of 1-4 carbons.
4. The method of claim 3, wherein the reactants further comprise a hydroxyalkyl acrylate;
the method for generating the modified polycarboxylate superplasticizer by carrying out polymerization reaction on the reactants comprises the following steps:
the reactants are subjected to polymerization reaction under the action of an initiator and a molecular weight regulator to generate a modified polycarboxylic acid water reducer;
wherein the method further comprises:
and adjusting the pH value of the modified polycarboxylic acid water reducing agent to 5-7.
5. The method of claim 4, wherein the step of polymerizing the reactants under the action of the initiator and the molecular weight regulator to generate the modified polycarboxylate water reducer comprises the following steps:
providing an aqueous solution of the unsaturated macromonomer, adding the first compound and the second compound under the condition of a preset reaction temperature range, and uniformly dispersing the first compound and the second compound in a preset rotating speed range to obtain a first mixed reaction system;
and (2) dropwise adding an unsaturated carboxylic acid and/or unsaturated carboxylic anhydride aqueous solution, a hydroxyalkyl acrylate aqueous solution, an initiator aqueous solution and a molecular weight regulator aqueous solution into the first mixed reaction system, and preserving heat for a preset time range after dropwise adding to generate the modified polycarboxylic acid water reducing agent.
6. The method of claim 5, wherein the predetermined reaction temperature range is 0-90 ℃; the predetermined rotating speed range is 320-480 r/min; the dripping time range is 0.2-6 h; the preset time range of heat preservation is 0-3 h;
wherein the molar ratio of the unsaturated macromonomer, the first compound, the second compound, the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride, and the hydroxyalkyl acrylate is in the range of 5: (2-3): (1-2): (3-10): (6-12);
wherein the using amount of the initiator is 0.5-3.0% of the total mass of the reactants; the dosage of the molecular weight regulator is 0.2-3.0% of the total mass of the reactants.
7. The method as claimed in claim 3, wherein the molecular weight of the unsaturated macromonomer is 600-5000, and the unsaturated macromonomer is at least one of methoxypolyethylene glycol methacrylate, methoxypolyethylene glycol acrylate, methoxypolyethylene glycol maleic acid monoester, 4-hydroxybutyl vinyl polyoxyethylene ether, allyl polyethylene glycol, 3-methyl-3-butene-1-polyethylene glycol, and 2-methallyl polyethylene glycol;
wherein the unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride is at least one of acrylic acid, methacrylic acid and maleic anhydride.
8. The method of claim 4, wherein the hydroxyalkyl acrylate is at least one of hydroxyethyl acrylate and hydroxypropyl acrylate;
wherein the initiator is at least one of a water-soluble redox initiation system, a water-soluble peroxide initiator and a water-soluble azo initiator;
wherein the molecular weight regulator is at least one of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol and sodium hypophosphite.
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