阅读说明：本技术 一种复合聚羧酸减水剂及其制备方法和应用 (Composite polycarboxylic acid water reducing agent and preparation method and application thereof ) 是由 张鑫 于 2021-08-27 设计创作，主要内容包括：本发明提供了一种复合聚羧酸减水剂及其制备方法和应用,属于建筑材料领域。本发明采用65-85％不饱和聚氧乙烯醚、3.5％～6％不饱和羧酸、1％～2.5％胺类有机小分子、0.4％～0.8％偶氮类氧化剂、10％～16％不饱和酯、0.15％～0.5％链转移剂、1％～2.5％中和剂,3-5％甲基丙烯酸二甲基氨基乙酯制成复合聚羧酸减水剂。本发明制备的复合聚羧酸减水剂在低掺量下具有高减水、高保坍稳定性同时分散性和抗粘土功能优异,且具有早强功能,制备方法操作简单、耗时短耗能低、反应温度适中、反应时间短、转化率高且绿色无污染。(The invention provides a composite polycarboxylate superplasticizer, and a preparation method and application thereof, and belongs to the field of building materials. The composite polycarboxylic acid water reducer is prepared from 65-85% of unsaturated polyoxyethylene ether, 3.5-6% of unsaturated carboxylic acid, 1-2.5% of amine organic micromolecules, 0.4-0.8% of azo oxidants, 10-16% of unsaturated esters, 0.15-0.5% of chain transfer agents, 1-2.5% of neutralizers and 3-5% of dimethylaminoethyl methacrylate. The composite polycarboxylate superplasticizer prepared by the invention has high water reduction, high slump loss resistance and excellent dispersibility and clay adhesion resistance under low mixing amount, and has an early strength function, and the preparation method has the advantages of simple operation, short time consumption, low energy consumption, moderate reaction temperature, short reaction time, high conversion rate, greenness and no pollution.)

1. The composite polycarboxylic acid water reducing agent is characterized by comprising the following components in percentage by mass: 65-85% of unsaturated polyoxyethylene ether, 3.5-6% of unsaturated carboxylic acid, 1-2.5% of amine organic micromolecule, 0.4-0.8% of azo oxidant, 10-16% of unsaturated ester, 0.15-0.5% of chain transfer agent, 1-2.5% of neutralizer and 3-5% of dimethylaminoethyl methacrylate, wherein the sum of the mass percentages of the components is equal to 100%.

2. The composite polycarboxylate water reducer according to claim 1, characterized in that the unsaturated polyoxyethylene ether is one or more of allyl alcohol polyoxyethylene ether, isobutenol polyoxyethylene ether or methallyl polyoxyethylene ether.

3. The compound polycarboxylate water reducer according to claim 1, characterized in that the unsaturated carboxylic acid is one or more of acrylic acid, hydroxyethyl acrylate, maleic anhydride or fumaric acid.

4. The composite polycarboxylate water reducer according to claim 1, wherein the amine organic small molecule is one or more of methylamine, ethylenediamine, triethylamine, cyclohexylamine, 2-hydroxyethylamine or trimethylhexadecylammonium hydroxide.

5. The composite polycarboxylate water reducer according to claim 1, characterized in that the azo-based oxidant is one or more of azobisisobutyronitrile, azobisisoheptonitrile and dimethyl azobisisobutyrate.

6. The compound polycarboxylate water reducer according to claim 1, characterized in that the unsaturated ester is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, isooctyl methacrylate or methyl methacrylate.

7. The composite polycarboxylate water reducer according to claim 1, wherein the chain transfer agent is one or more of thioglycolic acid, mercaptopropionic acid or sodium methallylsulfonate.

8. The composite polycarboxylate water reducer according to claim 1, characterized in that the neutralizing agent is one or more of potassium hydroxide, sodium hydroxide, ethanolamine, diethanolamine or triethanolamine.

9. The preparation method of the composite polycarboxylate water reducer according to claim 1, characterized by comprising the following steps:

(1) putting the unsaturated polyoxyethylene ether in the weight percentage into a reaction kettle, heating to 60-80 ℃, fully melting, and stirring for later use;

(2) mixing and stirring amine organic micromolecules and unsaturated carboxylic acid for 2-6h, and then adding unsaturated esters to obtain a mixed solution A;

(3) sequentially adding the mixed solution A, dimethylaminoethyl methacrylate, a chain transfer agent and an azo oxidant into the melted unsaturated polyoxyethylene ether, wherein the chain transfer agent and the azo oxidant are added in a uniform-speed dropwise adding mode for 1-4 h;

(4) after the dropwise addition is finished, preserving heat and aging for 2-4h, stopping the reaction, and discharging;

(5) adding a neutralizing agent to neutralize the polymerization product, adjusting the pH value to be 6-8, and cooling to obtain the composite polycarboxylic acid water reducing agent.

10. The use of the composite polycarboxylic acid water reducing agent according to any one of claims 1 to 8 in the field of cement concrete.

Technical Field

The invention relates to the field of building materials, and particularly relates to a composite polycarboxylic acid water reducing agent, and a preparation method and application thereof.

Background

The polycarboxylic acid water reducing agent is a third generation water reducing agent after lignin and naphthalene, and has the outstanding advantages of large net slurry fluidity, small slump loss, environmental protection and the like under the conditions of lower water-cement ratio and lower mixing amount. However, there are still some problems in its application. On one hand, in a low-temperature environment, the cement hydration speed is slow, the early strength is slow to develop, and the research on the early-strength polycarboxylate superplasticizer capable of obviously improving the early strength of concrete has remarkable significance. On the other hand, in the mixing process of the concrete, the sandstone resources in various countries gradually deteriorate due to the limitation of material sources, and the polycarboxylic acid water reducing agent is more sensitive to mineral substances in the clay than to cement, so that the polycarboxylic acid water reducing agent has a stronger adsorption tendency to the clay, which greatly influences the transportation, the retentivity, the strength and the like of the concrete in the construction process.

The patent with the application number of CN101497507A discloses an early-strength antifreezing polycarboxylic acid water reducing agent, which is prepared by esterification and polymerization to prepare a common polycarboxylic acid water reducing agent, adding different inorganic salts as early-strength components, and compounding to prepare the early-strength antifreezing polycarboxylic acid water reducing agent.

The patent with the application number of CN101357834B discloses an early strength type polycarboxylic acid superplasticizer, which is obtained by copolymerizing four monomers in an aqueous solution at the temperature of 60-95 ℃ in the presence of a free radical initiator and a chain transfer agent, and a new polymer molecular structure is formed by introducing a new polymerization monomer on a polymer molecular chain to improve the water reducing rate and the early strength capability of the polycarboxylic acid superplasticizer, but the polycarboxylic acid superplasticizer prepared by the patent has poor dispersibility and slump retention in concrete.

Disclosure of Invention

In view of the above, the invention provides a composite polycarboxylate superplasticizer, and a preparation method and application thereof.

The invention provides a composite polycarboxylic acid water reducing agent, which comprises the following components in percentage by mass: 65-85% of unsaturated polyoxyethylene ether, 3.5-6% of unsaturated carboxylic acid, 1-2.5% of amine organic micromolecule, 0.4-0.8% of azo oxidant, 10-16% of unsaturated ester, 0.15-0.5% of chain transfer agent, 1-2.5% of neutralizer and 3-5% of dimethylaminoethyl methacrylate, wherein the sum of the mass percentages of the components is equal to 100%.

Preferably, the unsaturated polyoxyethylene ether is one or more of allyl alcohol polyoxyethylene ether, isobutenol polyoxyethylene ether or methyl allyl polyoxyethylene ether.

Preferably, the unsaturated carboxylic acid is one or more of acrylic acid, hydroxyethyl acrylate, maleic anhydride or fumaric acid.

Preferably, the amine organic small molecule is one or more of methylamine, ethylenediamine, triethylamine, cyclohexylamine, 2-hydroxyethylamine or trimethylhexadecylammonium hydroxide.

Preferably, the azo oxidant is one or more of azobisisobutyronitrile, azobisisoheptonitrile and dimethyl azobisisobutyrate.

Preferably, the unsaturated ester is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, isooctyl methacrylate, or methyl methacrylate.

Preferably, the chain transfer agent is one or more of thioglycolic acid, mercaptopropionic acid or sodium methallylsulfonate.

Preferably, the neutralizing agent is one or more of potassium hydroxide, sodium hydroxide, ethanolamine, diethanolamine or triethanolamine.

The second purpose of the invention is to provide a preparation method of the composite polycarboxylic acid water reducing agent, which comprises the following steps:

(1) putting the unsaturated polyoxyethylene ether in the weight percentage into a reaction kettle, heating to 60-80 ℃, fully melting, and stirring for later use;

(2) mixing and stirring amine organic micromolecules and unsaturated carboxylic acid for 2-6h, and then adding unsaturated esters to obtain a mixed solution A;

(3) sequentially adding the mixed solution A, dimethylaminoethyl methacrylate, a chain transfer agent and an azo oxidant into the melted unsaturated polyoxyethylene ether, wherein the chain transfer agent and the azo oxidant are added in a uniform-speed dropwise adding mode for 1-4 h;

(4) after the dropwise addition is finished, preserving heat and aging for 2-4h, stopping the reaction, and discharging;

(5) adding a neutralizing agent to neutralize the polymerization product, adjusting the pH value to be 6-8, and cooling to obtain the composite polycarboxylic acid water reducing agent.

The third purpose of the invention is to provide the application of the composite polycarboxylate superplasticizer in the field of cement concrete

The invention has the following beneficial effects: the composite polycarboxylate superplasticizer provided by the invention has high water reduction and high slump loss resistance under low doping amount, has excellent dispersibility and clay adhesion resistance, and has an early strength function; the preparation method has the advantages of simple operation, short time consumption, low energy consumption, moderate reaction temperature, short reaction time, high conversion rate, greenness and no pollution.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. 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 test methods or test methods described in the following examples are conventional methods unless otherwise specified; the starting materials and auxiliaries are, unless otherwise specified, obtained from customary commercial sources or prepared in customary manner.

Example 1

The preparation process of the composite polycarboxylic acid water reducer comprises the following steps:

(1) adding 650g of allyl alcohol polyoxyethylene ether into a reaction kettle with a stirrer, adjusting the rotating speed of the stirrer to be 500r/min, raising the temperature in the reaction kettle to 60 ℃, and fully melting the allyl alcohol polyoxyethylene ether for later use;

(2) mixing and stirring 1g of ethylenediamine and 3.5g of acrylic acid at room temperature for 2 hours, and then adding 10g of hydroxyethyl acrylate to obtain a mixed solution A;

(3) sequentially adding the mixed solution A in the step (2), 3g of dimethylaminoethyl methacrylate, 0.15g of thioglycolic acid and 0.4g of azobisisobutyronitrile into the melted allyl alcohol polyoxyethylene ether, wherein the thioglycolic acid and the azobisisobutyronitrile are added in a uniform dropwise adding manner and are respectively added dropwise for 2 hours and 2.5 hours;

(4) after the dropwise addition, preserving heat and aging for 2-4h at 65-70 ℃, stopping the reaction, pouring out the product when the product is hot, and cooling at room temperature for discharging.

(5) Adding 1g of triethanolamine to neutralize the polymerization product, adjusting the pH value to 6, and cooling to obtain the composite polycarboxylic acid water reducer.

Example 2

The preparation process of the composite polycarboxylic acid water reducer comprises the following steps:

(1) adding 700g of allyl alcohol polyoxyethylene ether into a reaction kettle with a stirrer, adjusting the rotating speed of the stirrer to be 500r/min, raising the temperature in the reaction kettle to 70 ℃, and fully melting the allyl alcohol polyoxyethylene ether for later use;

(2) mixing 1.5g of methylamine and 4g of acrylic acid at room temperature, stirring for 3 hours, and then adding 11g of hydroxypropyl acrylate to obtain a mixed solution A;

(3) sequentially adding the mixed solution A in the step (2), 3.5g of dimethylaminoethyl methacrylate, 0.2g of thioglycolic acid and 0.5g of azobisisobutyronitrile into the melted allyl alcohol polyoxyethylene ether, wherein the thioglycolic acid and the azobisisobutyronitrile are added in a constant-speed dropwise adding manner and are respectively dropwise added for 2 hours and 2.5 hours;

(4) after the dropwise addition, preserving heat and aging for 2-4h at 65-70 ℃, stopping the reaction, pouring out the product when the product is hot, and cooling at room temperature for discharging.

(5) Adding 1.5g of triethanolamine to neutralize the polymerization product, adjusting the pH value to 6, and cooling to obtain the composite polycarboxylic acid water reducer.

Example 3

The preparation process of the composite polycarboxylic acid water reducer comprises the following steps:

(1) adding 750g of isobutylene alcohol polyoxyethylene ether into a reaction kettle with a stirrer, adjusting the rotating speed of the stirrer to be 500r/min, raising the temperature in the reaction kettle to 75 ℃, and fully melting the isobutylene alcohol polyoxyethylene ether for later use;

(2) mixing and stirring 2g of cyclohexylamine and 4.5g of hydroxyethyl acrylate at room temperature for 4 hours, and then adding 13g of hydroxyethyl methacrylate to obtain a mixed solution A;

(3) sequentially adding the mixed solution A in the step (2), 4g of dimethylaminoethyl methacrylate, 0.3g of thioglycolic acid and 0.6g of azobisisobutyronitrile into the molten isobutylene alcohol polyoxyethylene ether, wherein the thioglycolic acid and the azobisisobutyronitrile are added in a uniform dropwise adding manner and are respectively added dropwise for 2 hours and 2.5 hours;

(4) after the dropwise addition, preserving heat and aging for 2-4h at 65-70 ℃, stopping the reaction, pouring out the product when the product is hot, and cooling at room temperature for discharging.

(5) Adding 2g of triethanolamine to neutralize the polymerization product, adjusting the pH value to be 7, and cooling to obtain the composite polycarboxylic acid water reducer.

Example 4

The preparation process of the composite polycarboxylic acid water reducer comprises the following steps:

(1) adding 800g of isobutylene alcohol polyoxyethylene ether into a reaction kettle with a stirrer, adjusting the rotating speed of the stirrer to be 500r/min, raising the temperature in the reaction kettle to 75 ℃, and fully melting the isobutylene alcohol polyoxyethylene ether for later use;

(2) mixing 2.3g of 2-hydroxyethylamine and 5g of maleic anhydride at room temperature, stirring for 5 hours, and then adding 15g of hydroxypropyl methacrylate to obtain a mixed solution A;

(3) sequentially adding the mixed solution A in the step (2), 4.5g of dimethylaminoethyl methacrylate, 0.4g of thioglycolic acid and 0.7g of azobisisobutyronitrile into the molten isobutylene alcohol polyoxyethylene ether, wherein the thioglycolic acid and the azobisisobutyronitrile are added in a constant-speed dropwise adding manner and are respectively dropwise added for 2 hours and 2.5 hours;

(4) after the dropwise addition, preserving heat and aging for 2-4h at 65-70 ℃, stopping the reaction, pouring out the product when the product is hot, and cooling at room temperature for discharging.

(5) Adding 2.3g of triethanolamine to neutralize the polymerization product, adjusting the pH value to be 7, and cooling to obtain the composite polycarboxylic acid water reducing agent.

Example 5

The preparation process of the composite polycarboxylic acid water reducer comprises the following steps:

(1) adding 850g of methyl allyl polyoxyethylene ether into a reaction kettle with a stirrer, adjusting the rotating speed of the stirrer to be 500r/min, raising the temperature in the reaction kettle to 80 ℃, and fully melting the mixture for later use;

(2) mixing and stirring 2.5g of trimethylhexadecylammonium hydroxide and 6g of fumaric acid at room temperature for 6 hours, and then adding 16g of hydroxybutyl acrylate to obtain a mixed solution A;

(3) sequentially adding the mixed solution A in the step (2), 5g of dimethylaminoethyl methacrylate, 0.5g of thioglycolic acid and 0.8g of azobisisobutyronitrile into the molten methyl allyl polyoxyethylene ether, wherein the thioglycolic acid and the azobisisobutyronitrile are added in a uniform dropwise adding manner and are respectively added dropwise for 2 hours and 2.5 hours;

(4) after the dropwise addition, preserving heat and aging for 2-4h at 65-70 ℃, stopping the reaction, pouring out the product when the product is hot, and cooling at room temperature for discharging.

(5) Adding 2.5g of triethanolamine to neutralize the polymerization product, adjusting the pH value to be 8, and cooling to obtain the composite polycarboxylic acid water reducing agent.

Comparative example 1

The difference from example 1 is that hydroxyethyl acrylate in the starting material was removed and the same as in example 1 was repeated.

Comparative example 2

The difference from example 1 is that dimethylaminoethyl methacrylate in the raw material is removed, and the rest is the same as example 1.

And (3) performance testing:

the performance detection method comprises the following steps: in order to verify the beneficial effects of the invention, the composite polycarboxylate superplasticizers prepared in the above examples 1-5 and comparative examples 1-2 are adopted to test the fluidity of cement paste, the slump, the expansion degree and the compressive strength of a test piece before and after the admixture of the polycarboxylate superplasticizers. The cement used is ordinary portland cement. The test method refers to GB/T8077-2012 'test method for homogeneity of concrete admixture' to test the fluidity and the setting time of cement paste, when the W/C is 0 and the folded solid content is 0.20 wt% (relative to the cement dosage), the test method refers to GB/T50080-2002 'test method standard for performance of common concrete mixture' to test the slump and the expansion of concrete, and refers to GB/T17671-1999 'test method for cement strength' to test the compression strength of a test piece, and the mineral powder is wine steel S95-grade mineral powder; the fly ash is second-grade ash; the sand is machine-made sand, and the fineness modulus of the medium sand is 2.6; the concrete is characterized in that stones with the particle size of 5-25 are adopted, and cement is adopted in the concrete according to the mass ratio of the components: ore sand: fly ash: sand: stone: the water content is 170: 90: 80: 810: 1070: 150, the rubber-sand ratio is 1: 3, when the folding and fixing amount is 0.60 wt% (relative to the cement amount), adding a water reducing agent according to the proportion, wherein the stirring time is 180 seconds, and the vibrating time is 15 seconds; the glue-sand ratio is 1: 3, the concrete performance test results are shown in table 1.

TABLE 1

As can be seen from table 1: the composite polycarboxylate superplasticizer prepared by the invention is used for preparing the cement paste, and has good water reducing dispersion performance. Compared with comparative examples 1-2, the composite polycarboxylic acid water reducing agent prepared by the invention has lower slump loss and slump retention capacity, higher compressive strength and good flow property.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.