CN111378079A - Star-shaped polycarboxylate superplasticizer with controllable molecular structure and preparation method thereof - Google Patents
Star-shaped polycarboxylate superplasticizer with controllable molecular structure and preparation method thereof Download PDFInfo
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- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
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- 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
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- C08F2/00—Processes of polymerisation
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- 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
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- C08F2438/00—Living radical polymerisation
- C08F2438/03—Use of a di- or tri-thiocarbonylthio compound, e.g. di- or tri-thioester, di- or tri-thiocarbamate, or a xanthate as chain transfer agent, e.g . Reversible Addition Fragmentation chain Transfer [RAFT] or Macromolecular Design via Interchange of Xanthates [MADIX]
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Abstract
The invention provides a star polycarboxylic acid cement dispersant with a controllable molecular structure and a preparation method thereof. The star polycarboxylic acid water reducing agent with the controllable molecular structure is prepared by subjecting polyethylene polyamine and a chain transfer agent containing carboxyl to an amide/imidization reaction to obtain a star RAFT (reversible addition-fragmentation chain transfer) chain transfer agent, and then subjecting the star RAFT chain transfer agent, unsaturated acid, unsaturated phosphate and an unsaturated macromonomer to reversible addition-fragmentation chain transfer polymerization. The product produced by the invention has the advantages of low mixing amount, high water reducing rate, small slump loss, good cement adaptability, obvious reduction of slurry viscosity at low water-cement ratio and the like. Reversible addition-fragmentation chain transfer polymerization is adopted, the synthesis method is simple, the production process is clean, and the production cost is low.
Description
Technical Field
The invention relates to the technical field of concrete additives in building materials, in particular to a star polycarboxylic acid with a controllable molecular structure and capable of being used as a concrete high-performance water reducing agent and a preparation method thereof.
Background
With the rapid development of economy in China, modern buildings show the development trend of super-large span and super high rise, and higher requirements are put forward on the performances of strength, durability and the like of concrete. The addition of the high-performance polymer dispersant into the concrete is the most effective, most economical and most convenient technical approach for reducing the cement consumption, improving the utilization rate of industrial waste residues and realizing the high durability and performance improvement of the concrete. The polycarboxylate superplasticizer is an important component of modern high-performance concrete due to the excellent water-reducing dispersibility of the polycarboxylate superplasticizer. The excellent dispersing performance of the polycarboxylic acid water reducing agent is derived from a comb-shaped molecular structure, the main chain of the polycarboxylic acid water reducing agent is usually polyacrylic acid or polymethacrylic acid, and polyethylene glycols with different chain lengths are hydrophobic side chains. Through copolymerization with various functional monomers, various functional groups such as carboxyl, sulfonic group, hydroxyl, amino and the like can be introduced into polymer molecules, thereby realizing different macroscopic application performances. Due to incomparable application performance and diversified molecular structures of the polycarboxylic acid water reducing agent, the research on the structure and the performance of the polycarboxylic acid water reducing agent is active, and the polycarboxylic acid water reducing agent is more and more widely applied in recent years.
Given the monomer species, the performance enhancements of the synthesis of traditional comb-structured polycarboxylic acids have fallen into bottlenecks. The regulation of the distribution of the polycarboxylic acid sequence structure suggests a new direction for the high performance of polycarboxylic acids (Wang XM, Yang Y, Lin W, Shu X, Ran QP, Liu JP, Tailling the sequence structure of polycarboxylic acids to improve the failure sensitivity, Advances in CementResearch,2016,28(8),544 + 554). Star polymers are one of the new topologies, the compact structure of which provides a small hydrodynamic radius and a high density of functional group distribution.
On the other hand, when the water-cement ratio is low, the traditional comb-shaped polycarboxylic acid water reducing agent is used, such as a polyethylene glycol monomethyl ether methacrylate and (methyl) acrylic acid copolymer, the polymer shrinks in a cement pore solution due to a strong polyelectrolyte effect, only a small part of the polymer is adsorbed on the surfaces of cement particles, and most of the polymer is left in the solution to be complexed with each other, so that the viscosity of cement paste is increased, a series of construction problems of concrete stirring, transportation, pumping and the like are caused, and the popularization and application of high-strength and ultrahigh-strength concrete are limited to a great extent.
Patents CN102911322A and CN102887979B report that methacrylic acid and polyol are subjected to esterification reaction under the action of a catalyst to prepare a star-shaped polymerizable active end, and then the star-shaped polymerizable active end is subjected to radical polymerization reaction with an unsaturated polyoxyethylene ether macromonomer, a molecular weight regulator and an unsaturated carboxylic acid monomer under the action of an initiator to prepare the star-shaped polycarboxylic acid water reducer. Most of the polyhydric alcohol in the method exists in a solid form, and the methacrylic acid is liquid, so that the esterification reaction belongs to a heterogeneous reaction, the reaction is difficult, and the esterification rate is low. And the method has the problems of easy formation of crosslinked polymer and uncontrollable reaction.
Patent CN106519143B reports the use of multi-group chain transfer agents such as pentaerythritol tris (3-mercaptopropionate), triethanolamine tris (3-mercaptopropionate), glucose tetrakis (3-mercaptopropionate) and ethylenediamine tetra (2-mercaptoethyl acetate) to form polycarboxylic acid water reducers with multi-arm star structures, which has the disadvantage of low yield of star structures.
Patent CN105271897B reports that acyl bromination is performed with triethanolamine to obtain a star initiator with bromine as an end group, which initiates hydroxyethyl methacrylate to polymerize to obtain a water reducing agent with a star structure, and because the reactants do not use polyethylene glycol compounds, it is difficult to achieve steric hindrance effect similar to the side chain of the water reducing agent, so that a star polymer is obtained, but the star polymer is not an ideal star polycarboxylic acid water reducing agent structure.
Patent CN105669912B reports that organic molecules of hydroxyl groups of polyols and chain transfer agent containing carboxyl groups react with catalyst to obtain star RAFT chain transfer agent; then RAFT is carried out on the star polycarboxylic acid water reducer, the unsaturated acid small monomer, the unsaturated large monomer and the initiator to obtain the star polycarboxylic acid water reducer. The star-shaped RAFT chain transfer agent is prepared by esterification reaction of alcoholic hydroxyl and carboxylic acid, and the esterification reaction has the defects of difficult reaction, low yield and the like, so that the star-shaped RAFT chain transfer agent has uncontrollable structure and low yield.
Patent CN105669913B reports that organic molecules containing polyol hydroxyl group and organic molecules of halogenated acyl halide undergo esterification reaction to obtain multi-terminal halogen radical ATRP initiator; and then carrying out ATRP with an unsaturated acid small monomer, an unsaturated large monomer and a transition metal complex to obtain the star polycarboxylic acid water reducing agent. However, when unsaturated acids such as (meth) acrylic acid are directly subjected to ATRP, catalyst poisoning is easily caused, so that the yield is low during polymerization, even poly (meth) acrylic acid cannot be obtained by directly polymerizing (meth) acrylic acid, and poly (meth) acrylic acid (lanqianping and the like, preparation and characterization of a block polycarboxylic acid water reducing agent, science and engineering of high molecular materials, 2016,32:30-35) is generally obtained by a method of initiating polymerization and hydrolysis of tert-butyl (meth) acrylate and the like.
Disclosure of Invention
The invention aims to overcome the problems of insufficient initial dispersing performance of the cement dispersing agent at low water-cement ratio, high early viscosity of concrete and the like, and provides the star polycarboxylic acid water reducing agent with the controllable molecular structure, which has the advantages of easily available raw material sources, low production cost and simple production process, and the preparation method thereof.
This kind of water-reducing agent's star molecular structure, its high-density functional group distribute have increased with the adsorption driving power of cement granule, improved the adsorption capacity between its and the cement granule, increased the steric hindrance effect of molecule, star polycarboxylic acid makes its performance more traditional comb structure promote owing to improve polycarboxylic acid adsorption driving power and steric hindrance effect simultaneously. And due to the compact structure, compared with a linear structure with the same molecular weight, the star-shaped polymer has a smaller hydrodynamic radius and lower solution viscosity. The researchers of the present invention found that: the viscosity of the concrete at low water-to-gel ratios depends on the residual viscosity in the solution-lower solution residual viscosities result in lower concrete viscosities. Thus, the viscosity of concrete doped with the star polycarboxylic acid is effectively reduced compared with that of the linear polycarboxylic acid at the same doping amount.
The technical principle of the invention is as follows: the star polycarboxylic acid is synthesized by adopting reversible addition-fragmentation chain transfer polymerization and is applied to the cement dispersion process.
The star polycarboxylic acid water reducing agent with the controllable molecular structure is prepared by subjecting polyethylene polyamine and a chain transfer agent containing carboxyl to an amide/imidization reaction to obtain a star RAFT (reversible addition-fragmentation chain transfer) chain transfer agent, and then subjecting the star RAFT chain transfer agent, unsaturated acid, unsaturated phosphate and an unsaturated macromonomer to reversible addition-fragmentation chain transfer polymerization.
The polyethylene polyamine, hereinafter referred to as monomer A, is represented by the formula ①:
H(NHCH2CH2)mNH2①
wherein m is an integer of 1 to 4.
The chain transfer agent having a carboxyl group, hereinafter referred to as monomer B, is one or two selected from 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid, 2- (phenylthiocarbonylthio) propanoic acid, 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid, and 2- (dodecyltrithiocarbonate) -2-methylpropanoic acid in an arbitrary ratio.
Wherein the unsaturated acid, hereinafter referred to as monomer D, is represented by formula ②:
in the formula R1Is H or CH3；R2Is H or
z is an integer satisfying 0. ltoreq. z.ltoreq.3, when
When present, it can be reacted with COOM1Forming an acid anhydride; m1、M2Is H, alkali metal ion, 1/2 alkaline earth metal ion, ammonium ion or organic amine group;
the unsaturated phosphate-monomer E is represented by formula ③:
in the formula R3Is H or CH3(ii) a n is the number of carbon atoms and is an integer of 2-4; m3Is H, alkali metal ion, 1/2 alkaline earth metal ion, ammonium ion or organic amine group.
The unsaturated macromonomer-monomer F is represented by formula ④:
in the formula R4Is H or CH3，R5H or alkyl with 1-4 carbon atoms; x is O, CH2O, CH2CH2O, COO, respectively; AO is any one or a mixture of two or more of oxyalkylene groups having 2 to 4 carbon atoms, and y is an average addition mole number of AO and is an integer of 5 to 200; when AO in the structural unit of the homopolymer molecule is oxyalkylene with different carbon atom numbers, (AO) y is a random copolymerization or block copolymerization structure;
the monomer A is any one or more of ethylenediamine, diethylenetriamine, triethylene tetramine and tetraethylene pentamine which are mixed in any proportion;
the monomer B is any one or more than one of 4-cyano-4- (phenylthiocarbonylthio) valeric acid, 2- (phenylthiocarbonylthio) propionic acid, 4-cyano-4- [ (dodecyl sulfanyl thiocarbonyl) sulfanyl ] valeric acid and 2- (dodecyl trithiocarbonate) -2-methylpropanoic acid which are mixed in any proportion;
the monomer D is methacrylic acid, acrylic acid, maleic anhydride, itaconic anhydride, but is not limited thereto.
Monomer E can be synthesized according to the prior art in a number of ways: (1) the reaction of phosphoric acid with alcohols at elevated temperatures increases the reaction yield by means of water-carrying agents (US 20080108732). (2) Alcohol phosphorylation method (CN1158132A, US 20090258969).
The preparation method of the monomer E comprises the following steps of reacting unsaturated carboxylic ester with a phosphorylation reagent at 50-120 ℃, preferably 50-90 ℃, wherein the phosphorylation reaction time is 1-6 hours, preferably 2-4 hours, and the structure of the unsaturated carboxylic ester conforms to the general formula ⑤:
the unsaturated carboxylic ester is selected from hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate.
The monomer E is one or more of hydroxyethyl methacrylate phosphate, hydroxyethyl acrylate phosphate, hydroxypropyl acrylate phosphate and hydroxypropyl methacrylate phosphate which are mixed in any proportion.
The monomer F is at least one of substances having a structure represented by general formula ④, and is mixed in an arbitrary ratio.
The monomer F represented by the formula ④ in the present invention is a polyalkylene glycol mono (meth) acrylate monomer or an unsaturated polyalkylene glycol ether monomer.
When the monomer F represented by the formula ④ is a polyalkylene glycol mono (meth) acrylate monomer, it is an esterified product of an alkoxy polyalkylene glycol with (meth) acrylic acid or with (meth) acrylic anhydride, or an adduct of a hydroxyalkyl (meth) acrylate with at least one member selected from the group consisting of ethylene oxide, propylene oxide and butylene oxide, these monomers are used alone or as a mixture of two or more members in an arbitrary ratio, and when AO in the structural unit of the homopolymer molecule is an oxyalkylene group having a different carbon number, (AO) n is a random copolymer or block copolymer structure.
When the monomer F represented by the general formula ④ is an unsaturated polyalkylene glycol ether monomer, it is an adduct of an unsaturated alcohol and at least one of ethylene oxide, propylene oxide and butylene oxide, and these monomers are used singly or as a mixture of two or more thereof in an arbitrary ratio.
As the polyalkylene glycol mono (meth) acrylate monomer or the unsaturated polyalkylene glycol ether monomer which may be used as the monomer F, as long as the structural requirements of the general formula ④ are satisfied, the difference in kind thereof has little influence on the properties of the prepared star polycarboxylic acid.
The weight average molecular weight of the star polycarboxylic acid copolymer with the controllable molecular structure is 10,000-80,000. If the weight average molecular weight of the star polycarboxylic acid is too small or too large, both water-reducing and slump-retaining properties deteriorate.
The solid content of the star-shaped polycarboxylate superplasticizer with the controllable molecular structure is 20-60%.
The preparation method of the star polycarboxylic acid cement dispersant provided by the invention comprises the following specific steps:
1) amide/imidization reaction: heating the monomer A and the monomer B to 60 ℃ under the protection of nitrogen, adding a catalyst, slowly heating to 80-130 ℃, keeping the temperature for 2-6 hours, and cooling to obtain an acylation product C, namely a star RAFT chain transfer agent, wherein the molar ratio of the monomer A to the monomer B is as follows: 1:2 to 1:10
The catalyst is one or two of 4-dimethylamino pyridine, concentrated sulfuric acid, benzenesulfonic acid, p-toluenesulfonic acid and ethylsulfonic acid which are combined in any proportion, and the dosage of the catalyst is 0.05-10% of the total mass of the monomer A and the monomer B;
(2) reversible addition-fragmentation chain transfer polymerization: fully mixing the acylation product C-star RAFT chain transfer agent prepared in the step (1) with a monomer D, a monomer E and a monomer F, and then adding N2Under the protection condition, reversible addition-fragmentation chain transfer polymerization is carried out in an aqueous medium under the action of an initiator to obtain the polycarboxylate superplasticizer with the star structure, wherein the reaction temperature is 50-100 ℃, and the reaction time is 4-12 h. The acylation product C, monomerD. The molar ratio of the monomer E to the monomer F satisfies: F/(C + D + E) is 1/1-1/8, and the monomer C, the monomer D and the monomer E are mixed in any proportion;
the initiator is water-soluble 4,4' -azobis (4-cyanovaleric acid) or azobisisobutylamidine hydrochloride, and the dosage of the initiator is 0.5-5.0 percent of the total weight of the acylation product C, the monomer D, the monomer E and the monomer F.
The invention discloses an application method of a star polycarboxylic acid cement dispersant with a controllable molecular structure, which comprises the following steps: the mixing amount is 0.05-1 percent of the total weight of the cementing material,
the application method of the star-shaped polycarboxylic acid cement dispersant with the controllable molecular structure is the same as that of the existing water reducing agent, and only the mixing amount is slightly different. It is generally known to those skilled in the art that there is a certain relationship between the specific amount of water reducing agent and the type of water reducing agent used.
As an improvement, the mixing amount of the star polycarboxylic acid cement dispersant with the controllable molecular structure is 0.08-0.8%. If the mixing amount is too low, the dispersing effect on cement is unsatisfactory; the mixing amount is too high, which causes economic waste, and the dispersing effect is not further increased.
The star-shaped polycarboxylic acid cement dispersant with controllable molecular structure can also be mixed with at least one water reducing agent selected from sulfamic acid water reducing agents, lignin common water reducing agents and existing polycarboxylate water reducing agents known in the prior art for use. In addition, besides the known water reducing agents for concrete as set forth above, air entraining agents, expanding agents, retarders, early strength agents, tackifiers, shrinkage reducers, defoaming agents, and the like may be added thereto.
Compared with the prior art, the invention has the following advantages:
(1) the method has the advantages of simple synthesis method, clean production process, low process requirement, low production cost and little environmental pollution.
(2) The polycarboxylate superplasticizer prepared by the method has the advantages of low mixing amount, high water reducing rate, small slump loss, good cement adaptability, obvious reduction of slurry viscosity at low water-cement ratio and the like.
Detailed Description
The technical solution of the present invention is further described in detail with reference to the following examples.
For a better understanding of the present invention, the present invention will be further described with reference to the following examples.
In the examples of the present invention, the weight average molecular weight Mw of the polymer was measured by miniDAWN Tristar aqueous Gel Permeation Chromatograph (GPC) manufactured by Wyatt technology corporation; the experimental conditions were as follows: column: TSK-GELSW (TOSOH Corp.), eluent: 0.1M NaNO3The flow velocity: 0.8ml/min, injection: 20 μ l of 0.1% aqueous solution (differential refractometer).
Comparative example
30.0g of water was put into a four-neck flask equipped with a stirrer, a thermometer and a dropping device, the temperature was raised to 90 ℃, a mixed monomer solution of 100.0g of polyethylene glycol monomethyl ether methacrylate (Mn 1000g/mol), 18.0g of acrylic acid and 44.0g of water, a mixed solution of 1.8g of ammonium persulfate and 50.0g of water and a mixed solution of 1.21g of sodium bisulfite and 50.0g of water were simultaneously dropped into the reactor, the dropping time was 3 hours, after completion of the dropping, the temperature was kept at that temperature for 2 hours, and 14.3g of 35% NaOH solution was added to neutralize the solution, thereby obtaining a polycarboxylic acid water reducer mother liquor (Mw 24.53 kDa).
Example 1
Step 1) adding 60.0g of ethylenediamine and 452.6g of 2- (phenylthiocarbonylthio) propionic acid into a reactor, heating to 60 ℃ under the protection of nitrogen, adding 0.26g of concentrated sulfuric acid, continuously heating to 80 ℃, keeping the temperature for 6 hours, and cooling to obtain an acylation product C.
Step 2) into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel and a nitrogen inlet tube were charged 51.2g of acylate C, 14.4g of acrylic acid, 19.6g of hydroxyethyl acrylate phosphate, 200g of polyethylene glycol monomethyl ether acrylate (Mn 500g/mol), 1.43g of azobisisobutylamidine hydrochloride and 190.2g of water, and mixed to prepare a uniform aqueous monomer solution, and N was introduced thereinto to mix2Adding O in the solution2Discharge at N2Carrying out reversible addition-fragmentation chain transfer polymerization reaction under the protection, wherein the reaction temperature is 50 ℃, and the polymerization is carried out for 12h to obtain the star-shaped polymer with the solid content of 60.1 percent and the controllable molecular structureAnd the molecular weight of the carboxylic acid water reducing agent is 10.24 kDa.
Example 2
Step 1) adding 51.5g of diethylenetriamine and 698.5g of 4-cyano-4- (phenylthiocarbonylthio) valeric acid into a reactor, heating to 60 ℃ under the protection of nitrogen, adding 7.5g of benzenesulfonic acid, continuously heating to 110 ℃, keeping the temperature for 3 hours, and cooling to obtain an acylation product C.
Step 2) into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel and a nitrogen inlet tube, 47.1g of acylate C, 17.2g of methacrylic acid, 39.2g of hydroxyethyl acrylate phosphate, 200g of polyethylene glycol monomethyl ether methacrylate (Mn ═ 1000g/mol), 3.03g of 4,4' -azobis (4-cyanopentanoic acid), and 303.5g of an aqueous phase were added and mixed to prepare a uniform aqueous monomer solution, and N was introduced into the mixture to mix the aqueous monomer solution with stirring2Adding O in the solution2Discharge at N2And (3) carrying out reversible addition-fragmentation chain transfer polymerization reaction under protection, wherein the reaction temperature is 60 ℃, and the polymerization is carried out for 11h to obtain the star polycarboxylate superplasticizer with the controllable molecular structure and the solid content of 49.9%, and the molecular weight Mw is 26.48 kDa.
Example 3
Step 1) adding 51.5g of diethylenetriamine and 838.1g of 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid into a reactor, heating to 60 ℃ under the protection of nitrogen, adding 17.8g of 4-dimethylaminopyridine, continuously heating to 90 ℃, keeping the temperature for 5 hours, and cooling to obtain an acylation product C.
Step 2) into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel and a nitrogen inlet tube were charged 47.1g of acylate C, 20.0g of methacrylic acid, 21.0g of hydroxyethyl methacrylate phosphate, 200g of ethoxypolypropylene glycol polybutylene glycol monomethacrylate (Mn 2000g/mol), 5.76g of azobisisobutylamidine hydrochloride and 288.1g of water, and mixed to prepare a uniform aqueous monomer solution, and N was introduced thereinto to mix therewith2Adding O in the solution2Discharge at N2And (3) carrying out reversible addition-fragmentation chain transfer polymerization reaction under protection, wherein the reaction temperature is 70 ℃, and polymerization is carried out for 10h to obtain the star polycarboxylate superplasticizer with the solid content of 50.2% and the molecular weight of Mw (equal to 31.65 kDa) and controllable molecular structure.
Example 4
Step 1) adding 58.4g of triethylene tetramine and 1166.7g of 2- (dodecyl trithiocarbonate) -2-methylpropanoic acid into a reactor, heating to 60 ℃ under the protection of nitrogen, adding 36.8g of p-toluenesulfonic acid, continuously heating to 130 ℃, keeping the temperature for 2 hours, and cooling to obtain an acylation product C.
Step 2) A glass reactor equipped with a thermometer, a stirrer, a dropping funnel and a nitrogen inlet was charged with 48.1g of acylate C, 39.2g of maleic anhydride, 21.0g of hydroxypropyl acrylate phosphate, 240g of methylbutenyl polyoxyethylene ether (Mn 2400g/mol), 10.5g of azobisisobutylamidine hydrochloride and 522.5g of an aqueous phase, mixed to prepare a uniform aqueous monomer solution, N was introduced thereinto, and the mixture was stirred to prepare a uniform aqueous monomer solution2Adding O in the solution2Discharge at N2And (3) carrying out reversible addition-fragmentation chain transfer polymerization reaction under protection, wherein the reaction temperature is 80 ℃, and the polymerization is carried out for 8h to obtain the star polycarboxylate superplasticizer with the controllable molecular structure and the solid content of 39.8%, and the molecular weight of the star polycarboxylate superplasticizer is 78.27 kDa.
Example 5
Step 1) adding 58.4g of triethylene tetramine and 1453.2g of 4-cyano-4- [ (dodecyl sulfanyl thiocarbonyl) sulfanyl ] pentanoic acid into a reactor, heating to 60 ℃ under the protection of nitrogen, adding 75.6g of p-toluenesulfonic acid, continuously heating to 100 ℃, keeping the temperature for 4 hours, and cooling to obtain an acylation product C.
Step 2) into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel and a nitrogen inlet tube, 52.8g of acylate C, 25.8g of methacrylic acid, 11.2g of hydroxyethyl methacrylate phosphate, 240g of methylbutenyl polyoxyethylene ether (Mn 2400g/mol), 13.2g of 4,4' -azobis (4-cyanopentanoic acid) and 769.6g of an aqueous phase were added and mixed to prepare a uniform aqueous monomer solution, and N was introduced into the mixture to stir the aqueous monomer solution to prepare a uniform aqueous monomer solution2Adding O in the solution2Discharge at N2And (3) carrying out reversible addition-fragmentation chain transfer polymerization reaction under protection, wherein the reaction temperature is 90 ℃, and the polymerization is carried out for 5h to obtain the star polycarboxylate superplasticizer with the controllable molecular structure and the solid content of 30.1%, and the molecular weight Mw is 55.03 kDa.
Example 6
Step 1) adding 56.7g of tetraethylenepentamine and 1211.0g of 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid into a reactor, heating to 60 ℃ under the protection of nitrogen, adding 126.8g of ethylsulfonic acid, continuously heating to 120 ℃, keeping the temperature for 2 hours, and cooling to obtain an acylation product C.
Step 2) 66.2g of acylate C, 14.7g of maleic anhydride, 19.6g of hydroxypropyl methacrylate phosphate, 240g of allyl polyoxyethylene ether (Mn 8000g/mol), 16.6g of 4,4' -azobis (4-cyanovaleric acid), and 1325.7g of an aqueous phase were put into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, and a nitrogen inlet tube, mixed with stirring to prepare a uniform aqueous monomer solution, and N was introduced into the mixture2Adding O in the solution2Discharge at N2And (3) carrying out reversible addition-fragmentation chain transfer polymerization reaction under protection, wherein the reaction temperature is 100 ℃, and polymerizing for 4h to obtain the star polycarboxylate superplasticizer with the solid content of 20.3% and the molecular weight of the star polycarboxylate superplasticizer with the controllable molecular structure, wherein the molecular weight of the star polycarboxylate superplasticizer is 47.47 kDa.
The application example is as follows:
in the application example, the cement used is 52.5 PII in small wild field, Helin P.O 42.5 produced by Jiangsu Helin Cement Co., Ltd, the sand is medium sand with fineness modulus M of 2.6, the silica fume is Saipson silica fume produced by Shandong Boken silicon material Co., Ltd, and the surface area is 29900M2/kg。
Application example 1
Under the condition of low water-cement ratio, the influence of the star-shaped polycarboxylic acids with controllable molecular structures synthesized in the comparative examples and the examples on the dispersion performance of the fresh-mixed mortar is evaluated, the fixed water-cement ratio is 0.2, 1147.5g of small-field cement, 202.5g of silica fume and 1350g of sand are adopted, and the experimental results are shown in Table 1.
TABLE 1 Effect of different Star-shaped polycarboxylic acids on the Dispersion Performance of fresh-mixed mortars
In the case where the volume weight was kept substantially uniform, the comb-shaped polycarboxylic acid of the comparative example had an initial mortar flow of 282mm and a 30-min loss of 245mm with time at a blending amount of 0.8%. When the amount of the star polycarboxylic acid synthesized in the examples is 0.6% of the amount of cement, the initial fluidity of mortar and the loss with time of 30min are both better, such as example 2, the initial fluidity of mortar is 299mm, and the loss with time of 30min is 271 mm. Therefore, compared with the traditional comb-shaped polycarboxylic acid, the star-shaped polycarboxylic acid with the controllable molecular structure has the advantages of excellent cement dispersing performance under the condition of low water-cement ratio, low mixing amount, high water reducing rate and low slump loss.
Application example 2
The suitability of the star polycarboxylic acids obtained in comparative example and example 2 for different cements was evaluated, the fixed water cement ratio was 0.29, and the results of the net paste fluidity are shown in Table 2.
TABLE 2 adaptability of star polycarboxylate superplasticizer with controllable molecular structure to different cements
When the fixed water-cement ratio is 0.29, the star polycarboxylate water reducer having a controllable molecular structure prepared in synthesis example 2 has good initial dispersibility and good dispersion retention performance in any cement, and is good in adaptability to cement. In the cement of the small open field, when the same amount of the comparative example is added as the star-shaped polycarboxylic acid water reducing agent prepared in synthetic example 2, the initial fluidity of the comparative example is slightly inferior, and the dispersion retention performance is slightly inferior. In the rhinestone cement, the water reducing and dispersing effects of the comparative examples are obviously reduced, the inadaptability of the cement is shown, and the star polycarboxylate water reducer prepared by the invention has good dispersibility and dispersion retentivity in two types of cement, and has better adaptability and better comprehensive performance.
Application example 3
The effect of the star polycarboxylate water reducers prepared in the comparative example and example 2 of the present invention on the rheological properties of fresh mortar slurries was evaluated at 20 ℃ using a R/SP-SST rheometer (Brookfield, USA) and the rheology test procedure is shown in FIG. 1. When the fluidity of the freshly mixed mortar slurry (fixed water-cement ratio of 0.2, 1147.5g of small-field cement, 202.5g of silica fume and 1350g of sand) is comparable (about 300mm), the influence of different polycarboxylic acid water reducing agents on the rheological property of the freshly mixed mortar slurry is shown in FIG. 2.
From fresh mortar slurryThe same shear rate (14.8 s) can be seen in the rheological curves of the segments-1) When the shear viscosity of the comparative example is 19.4Pa.s, and the shear viscosity of the example 2 is 12.9Pa.s, therefore, the viscosity of the fresh slurry body is obviously reduced under the condition of low water-cement ratio by adopting the star-shaped polycarboxylic acid water reducing agent prepared by the invention at the same fluidity.
Claims (13)
1. A star-shaped polycarboxylate superplasticizer with a controllable molecular structure is characterized in that a star-shaped RAFT chain transfer agent is obtained by carrying out amide/imidization reaction on polyethylene polyamine and a chain transfer agent containing carboxyl, and then carrying out reversible addition-fragmentation chain transfer polymerization on the star-shaped RAFT chain transfer agent, unsaturated acid, unsaturated phosphate and an unsaturated macromonomer to obtain the star-shaped polycarboxylate superplasticizer;
the polyethylene polyamine, hereinafter referred to as monomer A, is represented by the formula ①:
H(NHCH2CH2)mNH2①
wherein m is an integer of 1 to 4;
a carboxyl group-containing chain transfer agent, hereinafter referred to as monomer B, selected from one or two of 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid, 2- (phenylthiocarbonylthio) propanoic acid, 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid, 2- (dodecyltrithiocarbonate) -2-methylpropanoic acid, in any ratio;
the unsaturated acid, referred to hereinafter as monomer D, is represented by formula ②:
in the formula R1Is H or CH3；R2Is H or
z is an integer satisfying 0. ltoreq. z.ltoreq.3, when
When present, it can be reacted with COOM1Forming an acid anhydride; m1、M2Is H, an alkali metalIons, 1/2 alkaline earth metal ions, ammonium ions, or organic amine groups;
the unsaturated phosphate ester, hereinafter referred to as monomer E, is represented by the general formula ③:
in the formula R3Is H or CH3(ii) a n is the number of carbon atoms and is an integer of 2-4; m3Is H, alkali metal ion, 1/2 alkaline earth metal ion, ammonium ion or organic amine group;
the unsaturated macromonomer, hereinafter referred to as monomer F, is represented by formula ④:
in the formula R4Is H or CH3，R5H or alkyl with 1-4 carbon atoms; x is O, CH2O, CH2CH2O, COO, respectively; AO is any one or a mixture of two or more of oxyalkylene groups having 2 to 4 carbon atoms, and y is an average addition mole number of AO and is an integer of 5 to 200; when AO in the structural unit of the homopolymer molecule is an oxyalkylene group having a different carbon number, (AO) y is a random copolymer or a block copolymer.
2. The star polycarboxylate superplasticizer according to claim 1, wherein the monomer A is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine, and is mixed in any proportion.
3. The star-shaped polycarboxylate superplasticizer according to claim 1, wherein said monomer B is one or more selected from 4-cyano-4- (phenylthiocarbonylthio) pentanoic acid, 2- (phenylthiocarbonylthio) propanoic acid, 4-cyano-4- [ (dodecylsulfanylthiocarbonyl) sulfanyl ] pentanoic acid, and 2- (dodecyltrithiocarbonate) -2-methylpropanoic acid, and the mixture thereof is mixed in any ratio.
4. The star polycarboxylate superplasticizer with a controllable molecular structure as claimed in claim 1, wherein the monomer D is methacrylic acid, acrylic acid, maleic anhydride or itaconic anhydride.
5. The star polycarboxylate superplasticizer with the controllable molecular structure as claimed in claim 1, wherein the monomer E is prepared by reacting unsaturated carboxylic ester with a phosphorylation reagent at 50-120 ℃ for 1-6 h, wherein the structure of the unsaturated carboxylic ester is in accordance with the general formula ⑤:
the unsaturated carboxylic ester is selected from hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate.
6. The star polycarboxylate superplasticizer with the controllable molecular structure as claimed in claim 5, wherein unsaturated carboxylic acid ester reacts with a phosphorylation reagent at 50-90 ℃; the phosphorylation reaction time is 2-4 h; obtaining the unsaturated carboxylic ester monomer E.
7. The star polycarboxylate superplasticizer with a controllable molecular structure as claimed in claim 1, 5 or 6, wherein said monomer E is one or more of hydroxyethyl methacrylate phosphate, hydroxyethyl acrylate phosphate, hydroxypropyl acrylate phosphate and hydroxypropyl methacrylate phosphate mixed in any proportion.
8. The star polycarboxylate water reducer with controlled molecular structure as claimed in claim 1, wherein said monomer F is a polyalkylene glycol mono (meth) acrylate monomer or an unsaturated polyalkylene glycol ether monomer.
9. The star polycarboxylic acid water reducing agent with the controllable molecular structure of claim 1, characterized in that the weight average molecular weight of the star polycarboxylic acid copolymer is 10,000-80,000.
10. The star polycarboxylate superplasticizer with the controllable molecular structure as claimed in claim 1, wherein the solid content of the star polycarboxylate superplasticizer is 20-60%.
11. The preparation method of the star polycarboxylate superplasticizer with the controllable molecular structure disclosed by claim 1 is characterized by comprising the following specific steps of:
1) amide/imidization reaction: heating the monomer A and the monomer B to 60 ℃ under the protection of nitrogen, adding a catalyst, slowly heating to 80-130 ℃, keeping the temperature for 2-6 hours, and cooling to obtain an acylation product C, namely a star RAFT chain transfer agent, wherein the molar ratio of the monomer A to the monomer B is as follows: 1: 2-1: 10;
the catalyst is one or two of 4-dimethylamino pyridine, concentrated sulfuric acid, benzenesulfonic acid, p-toluenesulfonic acid and ethylsulfonic acid which are combined in any proportion, and the dosage of the catalyst is 0.05-10% of the total mass of the monomer A and the monomer B;
(2) reversible addition-fragmentation chain transfer polymerization: fully mixing the acylation product C-star RAFT chain transfer agent prepared in the step (1) with a monomer D, a monomer E and a monomer F, and then adding N2Under the protection condition, under the action of an initiator, the star polycarboxylate superplasticizer with the controllable molecular structure is obtained by reversible addition-fragmentation chain transfer polymerization in an aqueous medium, wherein the reaction temperature is 50-100 ℃, and the reaction time is 4-12 h; the molar ratio of the acylation product C, the monomer D, the monomer E and the monomer F satisfies the following conditions: F/(C + D + E) is 1/1-1/8, and the monomer C, the monomer D and the monomer E are mixed in any proportion;
the initiator is water-soluble 4,4' -azobis (4-cyanovaleric acid) or azobisisobutylamidine hydrochloride, and the dosage of the initiator is 0.5-5.0 percent of the total weight of the acylation product C, the monomer D, the monomer E and the monomer F.
12. The method for using a molecular structure-controlled star polycarboxylic acid cement dispersant according to any of claims 1 to 9, characterized in that it is incorporated in an amount ranging from 0.05% to 1% by weight of the total cement.
13. The application method of claim 12, wherein the content of the star-shaped polycarboxylic acid cement dispersant with the controllable molecular structure is 0.08% -0.8%.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113354779A (en) * | 2021-08-09 | 2021-09-07 | 北京慕湖外加剂有限公司 | Esterified tea saponin modified composite water reducing agent and preparation method and application thereof |
| CN113413643A (en) * | 2021-07-26 | 2021-09-21 | 中建西部建设建材科学研究院有限公司 | Efficient settling method for waste slurry of concrete mixing plant |
| CN113736034A (en) * | 2021-08-25 | 2021-12-03 | 武汉三源特种建材有限责任公司 | Nanometer type super-long slump retaining polycarboxylate superplasticizer and preparation method thereof |
| CN116178617A (en) * | 2022-10-25 | 2023-05-30 | 江苏超力建材科技有限公司 | Star-shaped high-performance polycarboxylate superplasticizer and preparation method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102887979A (en) * | 2012-10-22 | 2013-01-23 | 北京工业大学 | Preparation method of star polycarboxylic acid high-performance water reducing agent |
| CN102911322A (en) * | 2012-10-22 | 2013-02-06 | 北京工业大学 | Synthesis method of polycarboxylic acid high-performance water reducing agent of star-like structure |
| US20130102749A1 (en) * | 2010-12-22 | 2013-04-25 | Jiangsu Subote New Materials Co.; Ltd | Preparation method of hyperbranched polycarboxylic acid type copolymer cement dispersant |
| WO2016045421A1 (en) * | 2014-09-22 | 2016-03-31 | 科之杰新材料集团有限公司 | Ether polycarboxylic acid slump-retaining agent and preparation method thereof |
-
2018
- 2018-12-31 CN CN201811651490.6A patent/CN111378079B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130102749A1 (en) * | 2010-12-22 | 2013-04-25 | Jiangsu Subote New Materials Co.; Ltd | Preparation method of hyperbranched polycarboxylic acid type copolymer cement dispersant |
| CN102887979A (en) * | 2012-10-22 | 2013-01-23 | 北京工业大学 | Preparation method of star polycarboxylic acid high-performance water reducing agent |
| CN102911322A (en) * | 2012-10-22 | 2013-02-06 | 北京工业大学 | Synthesis method of polycarboxylic acid high-performance water reducing agent of star-like structure |
| WO2016045421A1 (en) * | 2014-09-22 | 2016-03-31 | 科之杰新材料集团有限公司 | Ether polycarboxylic acid slump-retaining agent and preparation method thereof |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113413643A (en) * | 2021-07-26 | 2021-09-21 | 中建西部建设建材科学研究院有限公司 | Efficient settling method for waste slurry of concrete mixing plant |
| CN113354779A (en) * | 2021-08-09 | 2021-09-07 | 北京慕湖外加剂有限公司 | Esterified tea saponin modified composite water reducing agent and preparation method and application thereof |
| CN113354779B (en) * | 2021-08-09 | 2021-11-02 | 北京慕湖外加剂有限公司 | Esterified tea saponin modified composite water reducing agent and preparation method and application thereof |
| CN113736034A (en) * | 2021-08-25 | 2021-12-03 | 武汉三源特种建材有限责任公司 | Nanometer type super-long slump retaining polycarboxylate superplasticizer and preparation method thereof |
| CN116178617A (en) * | 2022-10-25 | 2023-05-30 | 江苏超力建材科技有限公司 | Star-shaped high-performance polycarboxylate superplasticizer and preparation method thereof |
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