CN113248663B - Early-strength functional monomer, early-strength polycarboxylate superplasticizer and preparation method thereof - Google Patents
Early-strength functional monomer, early-strength polycarboxylate superplasticizer and preparation method thereof Download PDFInfo
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- CN113248663B CN113248663B CN202110760818.3A CN202110760818A CN113248663B CN 113248663 B CN113248663 B CN 113248663B CN 202110760818 A CN202110760818 A CN 202110760818A CN 113248663 B CN113248663 B CN 113248663B
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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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- 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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- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
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- C04B24/2694—Copolymers containing at least three different monomers containing polyether side chains
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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- 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 disclosure discloses an early strength functional monomer, an early strength polycarboxylate superplasticizer and a preparation method thereof. The early strength functional monomer is prepared by the following steps: (1) adding an amino azo compound and unsaturated alcohol into a reaction vessel according to the proportion, and stirring until the azo compound is completely dissolved; (2) adding a polymerization inhibitor and a catalyst into a reaction container, gradually heating to 100 ℃, and carrying out reflux reaction for 5-8 h; (3) and (3) after the reaction is finished, cooling to 40 ℃, neutralizing with a sodium bicarbonate solution until the liquid is neutral, extracting with water for 3 times, recovering an organic phase, drying with anhydrous sodium sulfate for 12 hours, filtering and distilling to obtain the ester early strength functional monomer. The early strength type polycarboxylate water reducing agent that includes above-mentioned early strong function monomer can show under normal environment and improve the early strength of concrete and do not influence later stage intensity, and can reduce the viscosity of concrete, improves its water retention, and application scope is wide, is favorable to promoting and popularizing.
Description
Technical Field
The invention belongs to the technical field of concrete admixtures, and particularly relates to an early-strength functional monomer, an early-strength polycarboxylate superplasticizer and a preparation method thereof.
Background
With the adjustment of national housing industrialization policy, the proposal of green development concept and the deepening of sustainable development strategy, the development trend of the industry in future will gradually turn from premixed concrete to the direction of building industrialization and concrete prefabricated parts. The precast concrete component requires that the concrete has better workability, can meet the construction needs of the precast concrete component, and also has early strength performance, can improve the turnover rate of the template, accelerate the construction progress and improve the production efficiency. The means for improving the early strength performance of the member comprises the means of reducing the water-cement ratio, improving the cement dosage or using high-grade cement, adding an early strength agent and the like. However, reducing the water-cement ratio increases the viscosity of concrete, increasing the cement dosage increases the heat release of cement, increases the cracking risk of components, and when an inorganic salt early strength agent is compounded with a polycarboxylate water reducing agent, chloride ions are easily introduced, corrosion of reinforcing steel bars can be caused, salt precipitation and frost return on the surface of concrete can be caused, and in addition, the compatibility of some inorganic salts and the polycarboxylate water reducing agent is poor, and the early strength effect is very limited by adopting the compounding of a common polycarboxylate water reducing agent and triethanolamine. In addition, because the temperature is lower in winter in northern areas of China, water in concrete can be frozen, so that the ice expansion force damages a cement structure, and the later strength development of the concrete is influenced. In conclusion, the early strength water reducing agent capable of improving the early strength of concrete is developed on the premise of not influencing the workability and the later-stage volume stability of concrete, and becomes the key direction of the research in the field of polycarboxylic acid water reducing agents at the present stage.
The polycarboxylate superplasticizer serving as a third-generation superplasticizer has the advantages of high water reducing rate, small slump loss, good adaptability with cement, functional designability and the like, and is the most widely applied water reducing agent in the current market. At present, the researchers in China all research the early strength water reducing agent, and the early strength polycarboxylate water reducing agent is synthesized by introducing small monomers with the early strength function, large monomers with different molecular weights, changing different carboxyl densities, changing different molecular structures and the like.
Disclosure of Invention
In view of the above problems in the prior art, the first aspect of the present invention is to provide an early strength functional monomer; the second aspect of the present invention is to provide an early strength type polycarboxylic acid water reducing agent further comprising the above-mentioned early strength functional monomer; the third aspect of the present invention is to provide a method for producing the above-mentioned early strength type polycarboxylic acid water reducing agent.
In order to achieve the object of the first aspect, the present invention provides an early strength functional monomer, which is prepared by the following steps:
(1) adding an amino azo compound and unsaturated alcohol into a reaction vessel according to the proportion, and stirring until the azo compound is completely dissolved;
(2) adding a polymerization inhibitor and a catalyst into a reaction container, gradually heating to 100 ℃, and carrying out reflux reaction for 5-8 h;
(3) and (3) after the reaction is finished, cooling to 40 ℃, neutralizing with a sodium bicarbonate solution until the liquid is neutral, extracting with water for 3 times, recovering an organic phase, drying with anhydrous sodium sulfate for 12 hours, filtering and distilling to obtain the ester early strength functional monomer.
Preferably, when the early strength functional monomer is prepared, the azo compound containing amino is one or more selected from 4-aminophenylazobenzene-3-sulfonic acid, 4-dimethylaminoazobenzene-4-carboxylic acid, 5- [ (4-aminophenyl) azo ] -2-hydroxybenzoic acid, 4 '-aminoazobenzene-4-sulfonic acid, 4-amino-3-methyl-3' -sulfonatoazobenzene, and 3- [ (4-amino-3-methoxyphenyl) azo ] -benzenesulfonic acid; the unsaturated alcohol is selected from one or more of isopentenol, isobutene alcohol and 4-methyl-4-pentenol; the catalyst is selected from one of p-toluenesulfonic acid, phosphoric acid and toluenesulfonic acid; the polymerization inhibitor is one or a mixture of more of hydroquinone, phenothiazine and tert-butyl catechol.
Preferably, the molar ratio of the unsaturated alcohol to the amino azo compound in the preparation of the early strength functional monomer is 1.2-1.8: 1.
Preferably, when the early-strength functional monomer is prepared, the amount of the catalyst is 2.5-4% of the mass sum of the unsaturated alcohol and the amino azo compound.
Preferably, the amount of the polymerization inhibitor used in the preparation of the early-strength functional monomer is 0.2-1.5% of the mass sum of the unsaturated alcohol and the azo compound.
The early-strength polycarboxylic acid high-performance water reducing agent provided by the second aspect of the invention comprises the following components in parts by weight:
9-20 parts of the early strength functional monomer, 450-broken polyether monomer, 2-8 parts of silane monomer, 4.5-9 parts of quaternary ammonium cationic monomer, 27-40 parts of unsaturated carboxylic acid, 1.5-9 parts of initiator, 0.5-1.8 parts of reducing agent, 0.7-1.5 parts of chain transfer agent, 15-22 parts of neutralizer and 554 parts of water, wherein the polyether monomer is selected from any one or the mixture of methyl allyl polyoxyethylene ether and isoamylene polyoxyethylene ether with the molecular weight of 4000-5000; the silane monomer is selected from any one or mixture of more of methacryloxymethyltrimethylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, allyldimethoxysilane and allyltriethoxysilane; the quaternary ammonium cationic monomer is selected from one or a mixture of two of methacryloyloxyethyl trimethyl ammonium chloride and acryloyloxyethyl trimethyl ammonium chloride; the unsaturated carboxylic acid is selected from one or a mixture of more of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride and fumaric acid; the initiator is selected from one or a mixture of more of hydrogen peroxide, tert-butyl hydroperoxide, ammonium persulfate, potassium persulfate and sodium persulfate; the reducing agent is one or a mixture of more of vitamin C, sodium formaldehyde sulfoxylate, sodium bisulfite, sodium sulfite and glucose; the chain transfer agent is selected from one or a mixture of more of thioglycolic acid, mercaptopropionic acid, mercaptoethanol and sodium hypophosphite; the neutralizing agent is selected from 30% concentration water solution of sodium hydroxide or 30% concentration water solution of potassium hydroxide.
Preferably, the molecular weight of the polycarboxylate superplasticizer is 40000-70000.
The third aspect of the invention provides a preparation method of an early-strength polycarboxylate superplasticizer, which comprises the following steps:
uniformly stirring a polyether macromonomer, an early strength functional monomer, an initiator and a certain amount of water to obtain a solution A; uniformly stirring unsaturated carboxylic acid, quaternary ammonium cationic monomer, silane monomer and a certain amount of water to form a solution B; uniformly stirring a reducing agent, a chain transfer agent and a certain amount of water to form a solution C;
and dropwise adding the solution B, C into the solution A to perform free radical polymerization reaction to obtain the polycarboxylic acid water reducing agent.
Preferably, the method specifically comprises the following steps:
(1) heating the solution A while stirring, wherein the heating temperature is 40-60 ℃;
(2) after the temperature of the solution A reaches a set temperature, dropwise adding the solution B and the solution C into the solution A at the same time, wherein the dropwise adding time of the solution B is 2-3h, and the dropwise adding time of the solution C is 0.5h longer than that of the solution B;
(3) after the solution B and the solution C are completely dripped, continuously preserving the heat for 2-3 h;
wherein, in the solution A, the weight ratio of the early strength functional monomer, the polyether macromonomer, the initiator and the water is 9-20: 450-; in the solution B, the weight ratio of unsaturated carboxylic acid, quaternary ammonium cationic monomer, silane monomer and water is 22-40:4.5-9:2-8: 40-43; in the solution C, the weight ratio of the reducing agent to the chain transfer agent to the water is 0.5-1.8:0.7-1.5: 79-88.
Preferably, the method further comprises the step of adding a neutralizing agent into the polycarboxylic acid water reducing agent solution after the heat preservation is finished, and adjusting the pH value of the solution to be 6-7 to obtain the polycarboxylic acid water reducing agent with the concentration of about 45% -50%.
The invention has the following beneficial effects:
the invention adopts an early strength monomer synthesized by azo groups containing amino and unsaturated alcohol, wherein the azo groups and the amino both contain N atoms, lone electron pairs in the N atoms can form a stable complex with metal cations, the dissolution speed of tricalcium aluminate can be accelerated at the initial stage of cement hydration, the reaction of tricalcium aluminate is accelerated to generate ettringite, the ettringite is a needle-bar crystal which can be mutually overlapped to form a skeleton structure, and calcium silicate hydrate is filled in the skeleton structure to form a compact cement stone structure. With the reaction, the concentration of calcium ions and aluminum ions in the liquid phase is continuously reduced, so that the hydration rate of tricalcium silicate is continuously improved, and the early strength of the cement is improved.
The azo compound belongs to an aromatic azo compound, is different from an aliphatic azo compound, has stable thermal stability and light stability due to the conjugated effect of a benzene ring, can form a complex with cations respectively due to the two N atoms contained in the azo compound, has a synergistic effect with amino groups on the benzene ring, and can better improve the early strength of cement compared with the traditional amide early strength functional monomer.
The phenyl in the early strength functional monomer is a hydrophobic group, so that free water between water reducing agent molecules and cement particles is released, and the discharged free water can increase the thickness of a water film between the cement particles to play a role in lubrication. With the continuous hydration of cement, the ester group in the early strength functional monomer can be hydrolyzed, and the hydrolysis product contains-SO3H or-COOH groups can be adsorbed on cement particles for the second time, so that a water film can be better wrapped on the surfaces of the particles, the acting force among the cement particles is reduced, the synergistic lubrication effect is achieved, and the viscosity of the system is further reduced.
The quaternary ammonium cationic monomer is introduced, so that the water reducing agent has positive charges, can be adsorbed on the surfaces of positively charged cement particles and other negatively charged cementing materials, the adsorption capacity of water reducing agent molecules is improved, the water reducing agent molecules can better react with the cement particles, and meanwhile, the cationic monomer can promote C3And the hydration of S generates more C-S-H, and can obviously improve the early strength of the cement.
The silane groups introduced in the invention are strong polar groups, can be adsorbed on water reducing agent molecules, enhances the dispersibility of the water reducing agent molecules, effectively reduces the number and strength of flocculation structures in cement paste, and remarkably reduces the viscosity and yield stress of the cement paste, thereby achieving the effect of reducing the viscosity of the low water-cement ratio concrete.
The early-strength polycarboxylic acid high-performance water reducing agent prepared by the invention can obviously improve the early strength of concrete under normal environment without influencing the later strength, can reduce the viscosity of concrete and improve the water retention property, has wide application range, and is beneficial to popularization.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below.
It is to be understood that the described embodiments are only a few embodiments of the present disclosure, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the disclosure.
To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.
To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.
Example 1
The preparation method of the early-strength polycarboxylate superplasticizer comprises the following steps:
(1) synthesis of early strength functional monomer:
adding 129g of isopentenol into a four-neck flask with a stirrer, a thermometer and a reflux condenser, then adding 277g of 4-aminophenylazobenzene-3-sulfonic acid, stirring uniformly to fully fuse the two raw materials, then adding 12.18g of p-toluenesulfonic acid and 3.25g of hydroquinone into a reaction vessel, stirring and slowly heating to 100 ℃, carrying out reflux reaction for 7.5h, cooling to 40 ℃ after the reaction is finished, neutralizing with a sodium bicarbonate solution until the liquid is neutral, extracting with water for 3 times, recovering an organic phase, drying with anhydrous sodium sulfate for 12h, filtering out the solvent, distilling, continuously dripping the liquid at the condenser until no liquid is dropped, and obtaining the ester early-strength functional monomer ZQ-1 in a distillation flask.
(2) Synthesizing an early strength polycarboxylate superplasticizer:
455g of isoamylene polyoxyethylene ether with the molecular weight of 4000, 12g of early strength monomer ZQ-1 and 382g of water are added into a four-neck flask, stirred until the polyether is completely dissolved, then heated to 40 ℃, after the temperature is constant, 3.6g of hydrogen peroxide with the concentration of 30% is added, and the mixture is uniformly stirred to prepare solution A. A solution B was prepared from 30g of acrylic acid, 4g of methacryloyloxymethyltrimethylsilane, 5g of methacryloyloxyethyltrimethylammonium chloride and 43g of water, and a solution C was prepared from 1.1g of mercaptopropionic acid, 1.2g of vitamin C and 82g of water.
Simultaneously, dropwise adding the solution B and the solution C into the solution A, dropwise adding the solution B for 2 hours, dropwise adding the solution C for 2.5 hours, and preserving heat for 2 hours after dropwise adding. And (3) when the temperature is reduced to 30 ℃, slowly adding 17g of 30 mass percent sodium hydroxide solution, and fully stirring for 20min to obtain the early strength water reducing agent PC-1 with the mass percent of about 50%.
Example 2
The preparation method of the early-strength polycarboxylate superplasticizer comprises the following steps:
(1) synthesis of early strength functional monomer:
adding 115g of isobutylene into a four-neck flask with a stirrer, a thermometer and a reflux condenser, then adding 257g of 5- [ (4-aminophenyl) azo ] -2-hydroxybenzoic acid, stirring uniformly to fully fuse the two raw materials, then adding 10.42g of phosphoric acid and 2.23g of phenothiazine into a reaction container, slowly heating to 100 ℃ while stirring, carrying out reflux reaction for 6 hours, cooling to 40 ℃ after the reaction is finished, neutralizing with a sodium bicarbonate solution until the liquid is neutral, extracting with water for 3 times, recovering an organic phase, drying for 12 hours with anhydrous sodium sulfate, filtering out the solvent, distilling, continuing to drip the liquid at the condenser, and obtaining the ester early strength functional monomer ZQ-2 in a distillation flask.
(2) Synthesizing an early strength polycarboxylate superplasticizer:
460g of methylallyl polyoxyethylene ether with the molecular weight of 4500, 11g of early strength monomer ZQ-2 and 386g of water are added into a four-neck flask, stirred until polyether is completely dissolved, then heated to 45 ℃, after the temperature is constant, 6.5g of potassium persulfate is added, and the mixture is stirred uniformly to prepare solution A. 27g of methacrylic acid, 7.2g of vinyltrimethoxysilane, 6.6g of acryloyloxyethyltrimethylammonium chloride and 42g of water were used as a B liquid, and 0.9g of mercaptopropionic acid, 0.6g of sodium sulfite and 87g of water were used as a C liquid.
And simultaneously dripping the solution B and the solution C into the solution A, dripping the solution B for 2.5 hours, dripping the solution C for 3 hours, and preserving heat for 2.5 hours after dripping is finished. And (3) when the temperature is reduced to 30 ℃, slowly adding 20g of 30 mass percent potassium hydroxide solution, and fully stirring for 20min to obtain the early strength type water reducing agent PC-2 with the mass percent of about 49%.
Example 3
The preparation method of the early-strength polycarboxylate superplasticizer comprises the following steps:
(1) synthesis of early strength functional monomer:
adding 170g of 4-methyl-4-pentenol into a four-neck flask with a stirrer, a thermometer and a reflux condenser, then adding 307g of 3- [ (4-amino-3-methoxyphenyl) azo ] -benzenesulfonic acid, uniformly stirring to fully fuse the two raw materials, then adding 13.34g of toluenesulfonic acid and 3.82g of tert-butyl catechol into a reaction vessel, slowly heating to 100 ℃ while stirring, carrying out reflux reaction for 7.5h, cooling to 40 ℃ after the reaction is finished, neutralizing with a sodium bicarbonate solution until the liquid is neutral, recovering an organic phase, drying with anhydrous sodium sulfate for 12h, filtering out the solvent, distilling, continuously dripping the liquid at the condenser, and obtaining the ester early strength functional monomer ZQ-3 in a distillation flask.
(2) Synthesizing an early strength polycarboxylate superplasticizer:
455g of methyl allyl polyoxyethylene ether with the molecular weight of 4500, 15g of early strength monomer ZQ-3 and 400g of water are added into a four-neck flask, stirred until polyether is completely dissolved, then heated to 50 ℃, and after the temperature is constant, 5.8g of ammonium persulfate is added, stirred uniformly, and prepared into liquid A. A solution B was prepared from 32g of acrylic acid, 6.3g of vinyltriethoxysilane, 5.7g of acryloyloxyethyltrimethylammonium chloride and 41g of water, and a solution C was prepared from 1.1g of sodium hypophosphite, 0.5g of sodium formaldehyde sulfoxylate and 83g of water.
And simultaneously dripping the solution B and the solution C into the solution A, dripping the solution B for 2.5 hours, dripping the solution C for 3 hours, and preserving heat for 3 hours after the dripping is finished. And (3) when the temperature is reduced to 30 ℃, slowly adding 18g of 30 mass percent potassium hydroxide solution, and fully stirring for 20min to obtain the early strength water reducing agent PC-3 with the mass percent of about 48%.
Example 4
(1) Synthesis of early strength functional monomer:
adding 155g of 4-methyl-4-pentenol into a four-neck flask with a stirrer, a thermometer and a reflux condenser, then adding 291g of 4-amino-3-methyl-3' -sulfonic azobenzene, stirring uniformly to fully fuse the two raw materials, then adding 12.49g of p-toluenesulfonic acid and 3.57g of hydroquinone into a reaction vessel, slowly heating to 100 ℃ while stirring, carrying out reflux reaction for 7 hours, cooling to 40 ℃ after the reaction is finished, neutralizing with a sodium bicarbonate solution until the liquid is neutral, extracting with water for 3 times, recovering an organic phase, drying with anhydrous sodium sulfate for 12 hours, filtering out the solvent, distilling, continuously dripping the liquid at the condenser, and obtaining the ester early strength functional monomer ZQ-4 in a distillation flask.
(2) Synthesizing an early strength polycarboxylate superplasticizer:
458g of isoamylene polyoxyethylene ether with the molecular weight of 5000, 20g of early strength monomer ZQ-4 and 423g of water are added into a four-neck flask, stirred until the polyether is completely dissolved, then heated to 45 ℃, added with 8.2g of potassium persulfate after the temperature is constant, and stirred uniformly to prepare solution A. 28g of methacrylic acid, 7.5g of allyltriethoxysilane, 8.3g of methacryloyloxyethyltrimethylammonium chloride and 42g of water were prepared as a B solution, and 0.8g of mercaptoethanol, 0.7g of glucose and 86g of water were prepared as a C solution.
Simultaneously, dropwise adding the solution B and the solution C into the solution A, dropwise adding the solution B for 2 hours, dropwise adding the solution C for 2.5 hours, and preserving heat for 3 hours after dropwise adding. And (3) when the temperature is reduced to 30 ℃, slowly adding 17g of 30 mass percent potassium hydroxide solution, and fully stirring for 20min to obtain the early strength water reducing agent PC-4 with the mass percent of about 48%.
Actual test results
The four early strength water reducing agents of examples 1 to 4 were compared with 2 commercially available early strength water reducing agents by using C60 concrete as a test object, and the initial extension degree of concrete, the fresh concrete state, the inverted emptying time, and the compressive strengths of 1d, 3d, and 28d were compared.
The performance of the concrete mixture is tested according to GB/T50080-2016 Standard test method for the Performance of common concrete mixtures; the concrete strength is tested according to GB/T50081 and 2019 Standard of mechanical Properties test methods of ordinary concrete.
Table 1: concrete mixing proportion
| Material | Cement | Mineral powder | River sand | Stone | Water (W) | Additive agent |
| Dosage (kg) | 375 | 125 | 706 | 1059 | 155 | 10 |
Note: the additive is 10% solid, the fineness modulus of river sand is 2.8, and the broken stone is 5-25mm continuous graded broken stone.
The concrete effects of the early strength type polycarboxylate water reducers of examples 1 to 4 of the present invention and two commercially available early strength type polycarboxylate water reducers are compared as shown in Table 2.
Table 2: concrete Performance test results
As shown in Table 2, from the viewpoint of concrete workability and slump inversion emptying time, the two early strength water reducing agents sold in the market have the characteristics of slurry bleeding and poor wrapping property, and the concrete is thick and is inconvenient to construct. The early strength type water reducing agents of the 4 examples are basically consistent with two commercially available polycarboxylate water reducing agents in the aspect of expansion degree, the inverted emptying time is smaller than that of the two commercially available early strength type water reducing agents, the characteristics of softness and good fluidity of concrete are embodied, the phenomena of bleeding and water bleeding do not exist, and the water retention is good. From the aspect of strength, no matter the strength is 1d, 3d or 28d, the four examples are higher than two commercially available early strength water reducing agents, and particularly the strength of each age of the example 3 is the best, so that the early strength water reducing agent disclosed by the invention has an obvious early strength effect and has no influence on the later strength, and the reason is that the early strength water reducing agent disclosed by the invention can fully promote the hydration reaction of four minerals of cement, generates compact hydration products and improves the strength of concrete.
The above embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and the scope of the present invention is defined by the claims. Various modifications and equivalents may be made by those skilled in the art within the spirit and scope of the present invention, and such modifications and equivalents should also be considered as falling within the scope of the present invention.
Claims (9)
1. An early strength functional monomer prepared by:
(1) adding an amino azo compound and unsaturated alcohol into a reaction vessel according to the proportion, and stirring until the azo compound is completely dissolved;
(2) adding a polymerization inhibitor and a catalyst into a reaction container, gradually heating to 100 ℃, and carrying out reflux reaction for 5-8 h;
(3) after the reaction is finished, cooling to 40 ℃, neutralizing with a sodium bicarbonate solution until the liquid is neutral, extracting with water for 3 times, recovering an organic phase, drying with anhydrous sodium sulfate for 12 hours, filtering and distilling to obtain an ester early strength functional monomer;
wherein, when the early strength functional monomer is prepared, the azo compound containing amino is selected from one or more of 4-aminophenylazobenzene-3-sulfonic acid, 4-dimethylamine azobenzene-4-carboxylic acid, 5- [ (4-aminophenyl) azo ] -2-hydroxybenzoic acid, 4 '-aminoazobenzene-4-sulfonic acid, 4-amino-3-methyl-3' -sulfonic azobenzene and 3- [ (4-amino-3-methoxyphenyl) azo ] -benzenesulfonic acid; the unsaturated alcohol is selected from one or more of isopentenol, isobutene alcohol and 4-methyl-4-pentenol; the catalyst is selected from one of p-toluenesulfonic acid, phosphoric acid and toluenesulfonic acid; the polymerization inhibitor is one or a mixture of more of hydroquinone, phenothiazine and tert-butyl catechol.
2. The early strength functional monomer according to claim 1, wherein the molar ratio of the unsaturated alcohol to the amino azo compound is 1.2-1.8: 1.
3. The monomer with early strength function as claimed in claim 1, wherein the amount of the catalyst used in the preparation of the monomer with early strength function is 2.5-4% of the sum of the mass of the unsaturated alcohol and the mass of the amino azo compound.
4. The monomer according to claim 1, wherein the amount of the polymerization inhibitor used in the preparation of the monomer is 0.2-1.5% of the sum of the mass of the unsaturated alcohol and the mass of the azo compound.
5. The early-strength polycarboxylate superplasticizer comprises the following components in parts by weight:
9-20 parts of the early strength functional monomer, 450-465 parts of polyether macromonomer, 2-8 parts of silane monomer, 4.5-9 parts of quaternary ammonium cationic monomer, 27-40 parts of unsaturated carboxylic acid, 1.5-9 parts of initiator, 0.5-1.8 parts of reducing agent, 0.7-1.5 parts of chain transfer agent, 15-22 parts of neutralizer and 556 parts of water, wherein the polyether macromonomer is selected from any one or a mixture of two of methallyl polyoxyethylene ether and isoamylene polyoxyethylene ether with the molecular weight of 4000-5000; the silane monomer is selected from any one or mixture of more of methacryloxymethyltrimethylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, allyldimethoxysilane and allyltriethoxysilane; the quaternary ammonium cationic monomer is selected from one or a mixture of two of methacryloyloxyethyl trimethyl ammonium chloride and acryloyloxyethyl trimethyl ammonium chloride; the unsaturated carboxylic acid is selected from one or a mixture of more of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride and fumaric acid; the initiator is selected from one or a mixture of more of hydrogen peroxide, tert-butyl hydroperoxide, ammonium persulfate, potassium persulfate and sodium persulfate; the reducing agent is one or a mixture of more of vitamin C, sodium formaldehyde sulfoxylate, sodium bisulfite, sodium sulfite and glucose; the chain transfer agent is selected from one or a mixture of more of thioglycolic acid, mercaptopropionic acid, mercaptoethanol and sodium hypophosphite; the neutralizing agent is selected from 30% concentration water solution of sodium hydroxide or 30% concentration water solution of potassium hydroxide.
6. The early strength polycarboxylate water reducer as set forth in claim 5, wherein said polycarboxylate water reducer has a molecular weight of 40000-70000.
7. The method for preparing the early-strength type polycarboxylate superplasticizer according to claim 5 or 6, comprising the following steps:
uniformly stirring a polyether macromonomer, an early strength functional monomer, an initiator and a certain amount of water to obtain a solution A; uniformly stirring unsaturated carboxylic acid, quaternary ammonium cationic monomer, silane monomer and a certain amount of water to form a solution B; uniformly stirring a reducing agent, a chain transfer agent and a certain amount of water to form a solution C;
and dropwise adding the solution B, C into the solution A to perform free radical polymerization reaction to obtain the polycarboxylic acid water reducing agent.
8. The preparation method of the early-strength polycarboxylate water reducer as claimed in claim 7, comprising the following steps:
(1) heating the solution A while stirring, wherein the heating temperature is 40-60 ℃;
(2) after the temperature of the solution A reaches a set temperature, dropwise adding the solution B and the solution C into the solution A at the same time, wherein the dropwise adding time of the solution B is 2-3h, and the dropwise adding time of the solution C is 0.5h longer than that of the solution B;
(3) after the solution B and the solution C are completely dripped, continuously preserving the heat for 2-3 h;
wherein, in the solution A, the weight ratio of the early strength functional monomer, the polyether macromonomer, the initiator and the water is 9-20: 450-; in the solution B, the weight ratio of unsaturated carboxylic acid, quaternary ammonium cationic monomer, silane monomer and water is 22-40:4.5-9:2-8: 40-43; in the solution C, the weight ratio of the reducing agent to the chain transfer agent to the water is 0.5-1.8:0.7-1.5: 79-88.
9. The preparation method of the early-strength polycarboxylate water reducer as claimed in claim 8, wherein a neutralizer is added into the polycarboxylate water reducer solution after the heat preservation is finished, and the pH value of the solution is adjusted to be 6-7, so that the polycarboxylate water reducer with the concentration of 45-50% is obtained.
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| GB651315A (en) * | 1947-06-27 | 1951-03-14 | Du Pont | Improvements in and relating to processes for the polymerisation of ethylenically unsaturated compounds |
| CN105884978A (en) * | 2015-08-24 | 2016-08-24 | 科之杰新材料集团有限公司 | Coagulating early strength type polycarboxylate superplasticizer and preparing method thereof |
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