Concrete viscosity regulator and preparation method thereof
阅读说明：本技术 一种混凝土粘度调节剂及其制备方法 (Concrete viscosity regulator and preparation method thereof ) 是由 钟丽娜 方云辉 陈国荣 黄艳婷 柯余良 张小芳 郭元强 于 2019-12-12 设计创作，主要内容包括：本发明涉及建筑材料中混凝土材料技术领域,特别涉及一种混凝土粘度调节剂及其制备方法。其中,混凝土粘度调节剂可通过单体混合物的聚合获得,所述单体混合物包括可聚合还原剂、不饱和酸、不饱和酯,所述可聚合的还原剂具有叔氨基团和纤维素醚结构。通过在纤维素醚结构上引入可以与氧化剂作用的叔氨基,形成活性的自由基点,继续引发不饱和酸和不饱和酯的聚合,从而在纤维素醚的结构上引入了许多不饱和酸和不饱和酯的聚合物分子链,这些水溶性的分子链可以极大的提升纤维素醚的溶解性。本发明制备的混凝土粘度调节剂与减水剂复配使用,不会出现絮凝、分层现象,且能明显改善混凝土的包裹性、流动性、降低泌水离析现象,从而提升混凝土的工作性。(The invention relates to the technical field of concrete materials in building materials, in particular to a concrete viscosity regulator and a preparation method thereof. Wherein the concrete viscosity modifier is obtained by polymerizing a monomer mixture, wherein the monomer mixture comprises a polymerizable reducing agent, an unsaturated acid and an unsaturated ester, and the polymerizable reducing agent has a tertiary amino group and a cellulose ether structure. Tertiary amino groups capable of reacting with an oxidizing agent are introduced to a cellulose ether structure to form active free base points, and polymerization of unsaturated acid and unsaturated ester is continuously initiated, so that a plurality of polymer molecular chains of unsaturated acid and unsaturated ester are introduced to the cellulose ether structure, and the solubility of the cellulose ether can be greatly improved by the water-soluble molecular chains. The concrete viscosity regulator prepared by the invention is compounded with the water reducing agent for use, the phenomena of flocculation and layering are avoided, the wrapping property and the fluidity of the concrete can be obviously improved, and the phenomenon of bleeding and segregation is reduced, so that the workability of the concrete is improved.)
1. A concrete viscosity modifier is characterized in that: it is obtainable by polymerization of a monomer mixture comprising a polymerizable reducing agent having a tertiary amino group and a cellulose ether structure, an unsaturated acid, an unsaturated ester.
2. The concrete viscosity modifier of claim 1, wherein: the polymerizable reducing agent is prepared from a compound A and a compound B;
wherein the structural formula of the compound A is shown as the formula (I):
in the formula, R1Is methyl or ethyl;
R2is (CH)2)nN is 1-10, or is a benzene ring, or is ethoxybenzene;
R3is methyl or ethyl;
the structure of the compound B is shown as the formula (II):
wherein R is H, CH3、CH2CH2OH or
3. The concrete viscosity modifier of claim 1, wherein: the compound A comprises one of 2-diethylaminoethyl acetate, 2-dimethylaminoethyl acetate, 3-dimethylaminoethyl propionate, 4- (dimethylamino) ethyl butyrate, 4- (2- (dimethylamino) ethoxy) ethyl benzoate, 2-dimethylaminoethyl benzoate, p-N, N-dimethylaminobenzoate and 4-diethylaminomethyl benzoate.
4. The concrete viscosity modifier of claim 2, wherein: the compound B is one of hydroxyethyl methyl cellulose ether, hydroxypropyl methyl cellulose ether and hydroxypropyl methyl cellulose.
5. The concrete viscosity modifier of claim 4, wherein: the hydroxypropyl methylcellulose ether has a viscosity of at least 5000mPa · s.
6. The concrete viscosity modifier of claim 1, wherein the polymerizable reducing agent is prepared by the following steps:
dissolving a compound B in a proper amount of mixed solution of toluene and isopropanol, then adding a compound A, and carrying out ester exchange reaction in the presence of a catalyst and a polymerization inhibitor; and (3) carrying out ester exchange reaction at the temperature of 80-120 ℃ for 5-15 h, and removing the solvent through reduced pressure distillation after the reaction is finished to obtain the polymerizable reducing agent.
7. The concrete viscosity modifier of claim 6, wherein: the molar ratio of the anhydroglucose units of the compound A to the anhydroglucose units of the compound B is 0.02-3: 1.
8. The concrete viscosity modifier of claim 6, wherein: the catalyst is one of concentrated sulfuric acid, p-toluenesulfonic acid or 4-dimethylaminopyridine, and the amount of the catalyst is 0.5-30% of the mass of the compound B.
9. The concrete viscosity modifier of claim 6, wherein: the polymerization inhibitor is hydroquinone, phenothiazine or diphenylamine, and the dosage of the polymerization inhibitor is 0.01-0.2% of the mass of the compound B.
10. The concrete viscosity modifier of claim 1, wherein: the structure of the unsaturated acid is shown as the formula (III):
in the formula, R4Is H or COOH, R5Is H or CH3。
11. The concrete viscosity modifier of claim 10, wherein: the unsaturated acid includes acrylic acid and methacrylic acid.
12. The concrete viscosity modifier of claim 1, wherein: the structure of the unsaturated ester is shown as the formula (IV):
in the formula, R6Is H or CH3，R7Is H or CH3；R8Is CnH2nOH or CnH2nPO4，n＝1～20。
13. The concrete viscosity modifier of claim 12, wherein: the unsaturated ester is at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 2-methacryloyloxyethyl phosphate or 2-methacryloyloxypropyl phosphate.
14. A method for preparing a concrete viscosity modifier according to any one of claims 1 to 13, comprising the steps of:
placing a polymerizable reducing agent and a proper amount of deionized water into a reactor, stirring and dissolving, dropwise adding a mixed solution of unsaturated acid and unsaturated ester, an oxidant and a chain transfer agent into the reactor, adjusting the temperature to 10-50 ℃ for reaction, wherein the dropwise adding time is 1-3 h, keeping the temperature for 0.5-1.5 h after the dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator.
15. A concrete viscosity modifier according to claim 14, wherein: the oxidant is hydrogen peroxide or benzoyl peroxide.
16. A concrete viscosity modifier according to claim 14, wherein: the chain transfer agent is thioglycolic acid, mercaptopropionic acid or mercaptoethanol.
17. A concrete viscosity modifier according to claim 14, wherein: the mass ratio of the unsaturated acid to the unsaturated ester to the macromolecular reducing agent to the oxidizing agent to the chain transfer agent is 5-10: 1: 0.05-3: 1-3: 0.4-1.5.
Technical Field
The invention relates to the technical field of concrete materials in building materials, in particular to a concrete viscosity regulator and a preparation method thereof.
Background
Under the situation that natural sandstone resources are deficient and the state continuously strengthens the ore resources and the environmental protection, machine-made sandstone, sea sand, recycled aggregate and the like become main products of sandstone aggregate for basic facilities such as buildings, roads, bridges and the like in China. The use of machine-made sandstone, sea sand, recycled aggregate and other poor-quality sandstone generally leads to the deterioration of the workability of concrete, and is mainly reflected in that: the medium and low strength concrete has poor cohesiveness and has segregation and bleeding phenomena; the high-strength concrete has too high viscosity, which is not beneficial to pumping construction and the like. In engineering, the workability of concrete is improved by adding a concrete viscosity regulator to achieve good construction performance.
At present, the most widely used concrete viscosity regulators in China are cellulose series and propylene series, wherein the cellulose series is powder, the cellulose series is generally introduced into concrete by compounding with a water reducing agent, and a good concrete viscosity modification effect can be achieved when the mixing amount is 0.02-0.04% of the finished product of a single ton of water reducing agent. However, the cellulose-based viscosity modifier has a problem of solubility, a problem of long dissolution time in a water-reducing agent solution, and a problem of compatibility with the water-reducing agent, and is likely to cause delamination upon standing, thereby affecting the use effect of the water-reducing agent.
Chinese patent application CN 107382131a, published as 2017, 11, 24, discloses a concrete viscosity modifier and a preparation method thereof, mainly including cellulose ether, acrylic acid, acryloyloxyethyl trimethyl ammonium chloride, to solve the compatibility problem of concrete, however, the patent adopts an emulsion polymerization method to prepare, introduces more surfactants, and these surfactants may have adverse effects on the gas content, strength and durability of concrete.
Therefore, it is very necessary to provide a new solution to improve the solubility of cellulose ethers.
Disclosure of Invention
In order to solve the problem of solubility of the cellulose-based viscosity modifier mentioned in the above background, the present invention provides a concrete viscosity modifier which is obtainable by polymerization of a monomer mixture comprising a polymerizable reducing agent having a tertiary amino group and a cellulose ether structure, an unsaturated acid, and an unsaturated ester.
In the technical scheme, further, the polymerizable reducing agent is prepared from a compound A and a compound B;
wherein the structural formula of the compound A is shown as the formula (I):
in the formula, R1Is methyl or ethyl;
R2is (CH)2)nN is 1-10, or is a benzene ring, or is ethoxybenzene;
R3is methyl or ethyl;
the structure of the compound B is shown as the formula (II):
wherein R is H, CH3、CH2CH2OH, or
In the above technical solution, the compound a further includes one of ethyl 2-diethylaminoacetate, ethyl 2-dimethylaminoacetate, ethyl 3-dimethylaminopropionate, ethyl 4- (dimethylamino) butyrate, ethyl 4- (2- (dimethylamino) ethoxy) benzoate, 2-dimethylaminoethyl benzoate, ethyl p-N, N-dimethylaminobenzoate, and methyl 4-diethylaminobenzoate.
In the above technical solution, the compound B is one of hydroxyethyl methyl cellulose ether, hydroxypropyl methyl cellulose ether, and hydroxypropyl methyl cellulose.
Based on the above scheme, further, the viscosity of the hydroxypropyl methyl cellulose ether is at least 5000 mPa.s; preferably, the viscosity of the hydroxypropyl methylcellulose ether is 10 to 30 ten thousand mPa · s.
On the basis of the scheme, the preparation method of the polymerizable reducing agent comprises the following steps:
dissolving a compound B in a proper amount of mixed solution of toluene and isopropanol, then adding a compound A, and carrying out ester exchange reaction in the presence of a catalyst and a polymerization inhibitor; and (3) carrying out ester exchange reaction at the temperature of 80-120 ℃ for 5-15 h, and removing the solvent through reduced pressure distillation after the reaction is finished to obtain the polymerizable reducing agent.
In addition to the above embodiment, the molar ratio of the anhydroglucose units of compound a to compound B is 0.02 to 3:1, and preferably 0.1 to 1: 1.
On the basis of the scheme, the catalyst is one of concentrated sulfuric acid, p-toluenesulfonic acid or 4-dimethylaminopyridine, and the amount of the catalyst is 0.5-30% of the mass of the compound B.
On the basis of the scheme, the polymerization inhibitor is hydroquinone, phenothiazine or diphenylamine, and the amount of the polymerization inhibitor is 0.01-0.2% of the mass of the compound B.
On the basis of the scheme, the structure of the unsaturated acid is shown as the formula (III):
in the formula, R4Is H or COOH, R5Is H or CH3。
On the basis of the scheme, further, the unsaturated acid comprises acrylic acid and methacrylic acid.
On the basis of the scheme, the structure of the unsaturated ester is shown as the formula (IV):
in the formula, R6Is H or CH3，R7Is H or CH3；R8Is CnH2nOH or CnH2nPO4，n＝1～20。
In addition to the above embodiments, the unsaturated ester is at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 2-methacryloyloxyethyl phosphate, or 2-methacryloyloxypropyl phosphate.
The invention also provides a preparation method of the concrete viscosity regulator, which comprises the following steps:
placing a polymerizable reducing agent and a proper amount of deionized water into a reactor, stirring and dissolving, dropwise adding a mixed solution of unsaturated acid and unsaturated ester, an oxidant and a chain transfer agent into the reactor, adjusting the temperature to 10-50 ℃ for reaction, wherein the dropwise adding time is 1-3 h, keeping the temperature for 0.5-1.5 h after the dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator.
On the basis of the scheme, further, the oxidizing agent is hydrogen peroxide or benzoyl peroxide.
On the basis of the scheme, further, the chain transfer agent is thioglycolic acid, mercaptopropionic acid or mercaptoethanol.
On the basis of the scheme, the mass ratio of the unsaturated acid to the unsaturated ester to the macromolecular reducing agent to the oxidizing agent to the chain transfer agent is 5-10: 1: 0.05-3: 1-3: 0.4-1.5.
The concrete viscosity regulator provided by the invention relates to the following principles and beneficial effects:
the concrete viscosity regulator provided by the invention has the advantages that tertiary amino groups capable of acting with an oxidant are introduced into a cellulose ether structure to form active free base points, and the polymerization of unsaturated acid and unsaturated ester is continuously initiated, so that a plurality of polymer molecular chains of unsaturated acid and unsaturated ester are introduced into the cellulose ether structure, and the solubility of the cellulose ether can be greatly improved by the water-soluble molecular chains.
The concrete viscosity regulator and the water reducing agent are compounded for use, the phenomena of flocculation and layering are avoided, the wrapping property and the fluidity of the concrete can be obviously improved, and the phenomenon of bleeding and segregation is reduced, so that the workability of the concrete is improved.
In a preferred embodiment, the solubility of the cellulose ether can be further improved by introducing a plurality of tertiary amino groups on the cellulose ether structure through the transesterification reaction of the compound A and the compound B provided by the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following description will clearly and completely describe the embodiments of the present invention, and obviously, the described embodiments are a part of the embodiments of the present invention, but not all 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 invention.
The invention also provides the following embodiments:
firstly, preparing a polymerizable reducing agent.
Example 1
Adding 3g of 10 ten thousand mPa.s viscosity hydroxypropyl methyl cellulose ether, 120g of toluene and 40g of isopropanol into a four-neck flask provided with a stirrer, a water separator, a thermometer and a nitrogen guide pipe, stirring for dissolving, then adding 3g of 2-diethylaminoethyl acetate, 0.3g of concentrated sulfuric acid and 0.001g of hydroquinone, reacting for 10 hours at the reaction temperature of 90 ℃ under the stirring condition, and removing the solvent by reduced pressure distillation after the reaction is finished to obtain the polymerizable reducing agent C1.
Example 2:
4g of 10 ten thousand mPa.s viscosity hydroxypropyl methyl cellulose ether, 120g of toluene and 40g of isopropyl alcohol were put in a four-necked flask equipped with a stirrer, a water separator, a thermometer and a nitrogen gas introduction tube and dissolved by stirring. Then adding 3g of 2-dimethylamino ethyl acetate, 0.8g of 4-dimethylaminopyridine and 0.001g of hydroquinone, reacting for 10h at the reaction temperature of 90 ℃ under the condition of stirring, removing the solvent by reduced pressure distillation, and obtaining the polymerizable reducing agent C2 after the reaction is finished.
Example 3:
4g of 20 ten thousand mPa.s viscosity hydroxypropyl methyl cellulose ether, 120g of toluene and 40g of isopropyl alcohol were put in a four-necked flask equipped with a stirrer, a water separator, a thermometer and a nitrogen gas introduction tube and dissolved by stirring. Then adding 2.5g of 3-dimethyl amino ethyl propionate, 0.25g of concentrated sulfuric acid and 0.001g of phenothiazine, reacting for 10 hours at the reaction temperature of 90 ℃ under the condition of stirring, and removing the solvent by reduced pressure distillation after the reaction is finished to obtain the polymerizable reducing agent C3.
Example 4:
4g of 20 ten thousand mPa.s viscosity hydroxypropyl methyl cellulose ether, 120g of toluene and 40g of isopropyl alcohol were put in a four-necked flask equipped with a stirrer, a water separator, a thermometer and a nitrogen gas introduction tube and dissolved by stirring. Then adding 2.5g of 3-dimethyl amino ethyl propionate, 0.5g of 4-dimethyl aminopyridine and 0.001g of hydroquinone, reacting for 10h at the reaction temperature of 90 ℃ under the condition of stirring, and removing the solvent by reduced pressure distillation after the reaction is finished to obtain the polymerizable reducing agent C4.
Secondly, preparation of concrete viscosity regulator
Example 5
Placing 0.2g of polymerizable reducing agent C1 and 100g of deionized water in a reactor, stirring for dissolving, dropwise adding a mixed solution of 20g of acrylic acid and 4g of hydroxyethyl methacrylate, 2g of aqueous hydrogen peroxide and 0.9g of aqueous thioglycolic acid into the reactor, reacting at room temperature for 1.5h, keeping the temperature for 1h after dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator D1.
Example 6
Placing 0.25g of polymerizable reducing agent C2 and 100g of deionized water in a reactor, stirring for dissolving, dropwise adding a mixed solution of 20g of acrylic acid and 3g of hydroxyethyl methacrylate, 2.5g of aqueous hydrogen peroxide and 0.8g of aqueous mercaptopropionic acid into the reactor, reacting at room temperature for 1.5h, preserving heat for 1h after dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator D2.
Example 7
Placing 0.18g of polymerizable reducing agent C3 and 100g of deionized water in a reactor, stirring for dissolving, dropwise adding a mixed solution of 20g of acrylic acid and 4g of hydroxyethyl methacrylate, 2.1g of aqueous hydrogen peroxide and 0.6g of aqueous mercaptoethanol in the reactor, reacting at room temperature for 1.5h, preserving heat for 1h after dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator D3.
Example 8
Placing 0.15g of polymerizable reducing agent C4 and 100g of deionized water in a reactor, stirring for dissolving, dropwise adding a mixed solution of 20g of acrylic acid and 4g of hydroxyethyl methacrylate, 2g of aqueous hydrogen peroxide and 0.7g of aqueous mercaptopropionic acid into the reactor, reacting at room temperature for 1.5h, keeping the temperature for 1h after dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator D4.
Example 9
Placing 0.2g of polymerizable reducing agent C3 and 100g of deionized water in a reactor, stirring for dissolving, dropwise adding a mixed solution of 20g of acrylic acid and 4g of hydroxyethyl acrylate, 2.2g of aqueous hydrogen peroxide and 0.8g of aqueous mercaptopropionic acid into the reactor, reacting at room temperature for 1.5h, keeping the temperature for 1h after dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator D5.
Example 10
Putting 0.3g of polymerizable reducing agent C3 and 100g of deionized water into a reactor, dropwise adding a mixed solution of 20g of acrylic acid and 3g of 2-methacryloyloxyethyl phosphate, 2g of aqueous hydrogen peroxide and 0.7g of aqueous mercaptopropionic acid into the reactor, reacting at room temperature for 1.5h, keeping the temperature for 1h after dropwise adding is finished, cooling to room temperature after the reaction is finished, and adjusting the pH to 6-7 by using liquid alkali to obtain the concrete viscosity regulator D6.
Concrete viscosity modifier samples synthesized in examples 5 to 10, commercially available cellulose ether modifiers (comparative examples, product types of HPMC, HPC, and HEC), and commercially available polycarboxylate superplasticizer mother liquor (product type of Point-TS8) were prepared into aqueous solutions, left to stand for 10 days, and the compatibility was observed, with the test results shown in table 1.
TABLE 1 compatibility test results with Water reducing Agents
Sample numbering
Compounded composition
Compound formula (quality ratio)
Compatibility
1
Water reducing agent and water
50：500
Clear and no floccule
2
10 ten thousand mPa.s HPMC, water reducing agent and water
0.15：50：500
Layered with floc
3
20 ten thousand mPa.s HPMC, water reducing agent and water
0.15：50：500
Layered with floc
4
HEMC + water reducing agent + water
0.15：50：500
Layered with floc
5
Example 5+ Water reducing agent + Water
2：50：500
Clear and no floccule
6
Example 6+ Water reducing agent + Water
2：50：500
Clear and no floccule
7
Example 7+ Water reducing agent + Water
2：50：500
Clear and no floccule
8
Example 8+ Water reducing agent + Water
2：50：500
Clear and no floccule
9
Example 9+ Water reducing agent + Water
2：50：500
Clear and no floccule
12
Example 10+ Water reducing agent + Water
2：50：500
Clear and no floccule
As can be seen from Table 1, the concrete viscosity modifier obtained by the invention can be well dissolved in the polycarboxylate superplasticizer solution no matter with the same mass or compared with the same solid content, and the comparative example and the polycarboxylate superplasticizer have a small amount of floccules after standing for 10 days, which shows that the compatibility of the two is poor.
A compound sample of the water reducing agent and the viscosity regulator in the table 1 is subjected to concrete test, standard cement is adopted, the mixing amount is 0.18 percent (folded into solid parts) of the mass of the cement, and the concrete slump, the concrete slump expansion, the concrete bleeding distance and the normal-pressure bleeding rate are measured according to GB 8076 + 2008 concrete admixture. The concrete mixing proportion is as follows: cement 360kg/m3790kg/m of sand3Stone 1050kg/m3170kg/m of water3The results obtained are shown in table 2:
TABLE 2 concrete test results
The test results in table 2 show that the concrete viscosity modifiers prepared in the embodiments 5 to 10 of the invention can effectively improve the segregation and bleeding phenomena of concrete and can improve the slump retaining performance of concrete compared with comparative examples.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
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