CN114437299A

CN114437299A - Anti-mud polycarboxylate superplasticizer mother liquor

Info

Publication number: CN114437299A
Application number: CN202210269317.XA
Authority: CN
Inventors: 宋远明; 周正; 王志娟
Original assignee: Yantai University
Current assignee: Yantai University
Priority date: 2022-03-18
Filing date: 2022-03-18
Publication date: 2022-05-06
Anticipated expiration: 2042-03-18
Also published as: CN114437299B

Abstract

The invention relates to a mud-resistant polycarboxylate superplasticizer mother liquor, in particular to a polycarboxylate superplasticizer mother liquor synthesized by using dicarboxylic ester and tetraethyleneglycol diacrylate. The mud-resistant polycarboxylate superplasticizer mother liquor prepared by the invention has mud resistance, slump loss resistance and slow release performance, and can also obviously improve the workability of concrete.

Description

Anti-mud polycarboxylate superplasticizer mother liquor

Technical Field

The invention relates to a mud-resistant polycarboxylate superplasticizer mother liquor, and particularly relates to a polycarboxylate superplasticizer mother liquor synthesized by using dicarboxylic ester and tetraethyleneglycol diacrylate.

Background

The polycarboxylate superplasticizer has the advantages of good comprehensive performance, high degree of freedom in molecular structure adjustment, environmental friendliness and the like, and the market share is gradually improved in recent years. The national yield of the polycarboxylic acid water reducing agent accounts for 26 percent of the total amount of the water reducing agent in 2009, and the specific gravity is rapidly increased to 78 percent in 2017. This indicates that the application of polycarboxylic acid water reducing agents in the field of civil engineering and architecture has become very popular.

It is well known that sand is an important constituent material of concrete. In recent years, because of huge demand, high-quality sand is almost consumed, and a large number of concrete mixing stations use sand with higher mud content to mix concrete at present. The clay mineral in the grit can adsorb polycarboxylate water reducing agent molecule in a large number, seriously reduces water reducing agent effect, and main specific surface is present: the initial state of the concrete can not be opened, the flow state of the concrete is extremely poor, the dosage of the water reducing agent is obviously increased, and the concrete slump loss can not meet the construction requirement with time. For this reason, there have been a number of academic studies and patents discussing how to try to eliminate the adverse effects of mud content.

Through inquiring relevant data in a China Hopkinson area database and a China patent website, a plurality of papers and patents relate to a polycarboxylic acid water reducer mud-resisting technology. After studying and reading the data and finding out that the problem is solved by two methods: firstly, adding a certain mud-resistant functional component into the synthesized polycarboxylate superplasticizer mother liquor in a compounding manner to improve the mud resistance of the polycarboxylate superplasticizer mother liquor; secondly, in the synthesis process of the polycarboxylate superplasticizer mother liquor, certain unsaturated functional monomer is introduced into the free radical copolymerization reaction, so that the mud resistance is improved.

(1) Compounding of mud-resistant functional component and polycarboxylate superplasticizer mother liquor

During compounding, Wanglinong (Wanglinong, an additive for inhibiting the negative effect of clay on a polycarboxylate superplasticizer and an action mechanism thereof [ D ]. Chongqing university, 2015.) uses three different substances such as polyethylene glycol-4000, potassium chloride and trimethyl hexadecyl ammonium bromide as an anti-mud agent.

The research on the anti-mud pumping agent based on the polycarboxylic acid high-efficiency water reducing agent [ J ] silicate report, 2016 (1 month) and 101-105.) selects polyethylene glycol, beta-cyclodextrin and dimethyl diallyl ammonium chloride as an adsorption component, a complexing component and a clay stabilizing component of clay respectively.

The composition is prepared by adding a certain amount of polyethylene glycol into a compounded process of Zhuhongjiao and the like (Zhuhongjiao, Zhangguanghua, Wangzui Ru. polyethylene glycol for inhibiting the influence and action mechanism [ J ] of montmorillonite on the polycarboxylic acid water reducer, university of Shanxi science and technology (Nature science edition), 2016,34(06): 110-115.) so as to improve the mud resistance of the polycarboxylic acid water reducer.

Queen steel and the like (Wang steel, Lujiayue, Liujiazhong, improving adaptability of polycarboxylic acid superplasticizer and montmorillonite and mechanism research thereof [ J ] architecture materials, 2017,20(4):556 and 562.) in the process of compounding, quaternary ammonium salt is used as a cation sacrificial agent.

Zhang Guanghua et al (Zhang Guanghua, Wang Shuang, Zhang Zi Quaternary ammonium salt improves the sensitivity of polycarboxylate water reducing agent to clay [ J ]. The building materials academic newspaper, 2019,22(1): 81-86.) reacts with 1, 4-dibromobutane, 1, 5-dibromopentane and p-dibromide benzyl respectively with triethylamine to synthesize 3 kinds of cation gemini quaternary ammonium salts, and the cation gemini quaternary ammonium salts are compounded with polycarboxylate water reducing agent.

The patent 'polycarboxylic acid cation mud-resisting agent and the preparation method and application thereof' (application No. 201610136882.3, in the right state), uses synthetic copolymer of hydroxypropyl methacrylate, acrylic acid and sodium methallyl sulfonate as mud-resisting agent to be compounded with polycarboxylic acid water reducing agent.

The patent of 'a mud-resistant polycarboxylate superplasticizer, a preparation method and application thereof in concrete' (application No. 201710271003.2, in an actual examination state) adopts quaternized lignosulfonate as a mud-resistant component to be compounded with the polycarboxylate superplasticizer.

The patent 'a combined anti-mud agent based on a polycarboxylic acid pumping agent, an anti-mud pumping agent and a preparation method thereof' (application No. 201810390077.2, in a right state) adopts a mixture consisting of calcium nitrate, polyethylene glycol, beta dextrin and dimethyl diallyl ammonium chloride as an anti-mud component to be compounded with a polycarboxylic acid water reducing agent.

The patent 'anti-mud small material for compounding polycarboxylate superplasticizer and a using method thereof' (application No. 201810390077.2, in practical examination state) adopts sodium pyrosulfite, sodium hexametaphosphate, sodium tripolyphosphate and sodium nitrate which are mixed in proportion as anti-mud components to be compounded with polycarboxylate superplasticizer.

In the patent of concrete mud-resisting agent (application No. 201911240269.6, in the state of examination), acrylic acid, maleic anhydride, 2-acrylamide-2-methylpropanesulfonic acid, a cationic polymerization small monomer, a chain transfer agent and an initiator are polymerized according to a certain proportion to obtain the mud-resisting agent, and the mud-resisting agent is compounded with a polycarboxylic acid water reducing agent.

The patent 'a composite concrete anti-mud agent and a using method thereof' (application number 202011392801.9, in a practical examination state) is prepared by compounding sodium silicate, polyethylene glycol, amino trimethylene phosphonic acid, dodecyl trimethyl ammonium chloride and the like with a polycarboxylic acid water reducing agent according to a certain proportion.

In the patent of 'a preparation method of a concrete anti-mud agent' (application No. 202110614032.0, in an actual examination state), organic amine, an alkylene oxide monomer, a catalyst and halogenated hydrocarbon react under certain temperature and pressure conditions to obtain the anti-mud agent, and the anti-mud agent is compounded with a polycarboxylic acid water reducing agent.

(2) Introducing double bond-containing unsaturated functional monomer into polycarboxylic acid mother liquor for polymerization reaction

Wuwei et al (Wuwei, Liu Zhaoyang, leaf, high-adaptability phosphate group modified polycarboxylic acid water reducing agent synthesis and characterization [ J ] novel building material, 2016,43(8): 39-41.) found that the phosphate group of the side chain of the water reducing agent not only improves the dispersing ability for cement, but also effectively reduces the agglomeration effect of cement particles through the complexation effect, thereby reducing the loss of fluidity with time.

Shao Qiang (Shao Qiang, Sunshimei, Lin Chun. preparation of styrene/cyclodextrin polycarboxylate superplasticizer and mud resistance research [ J ]. novel building material, 2016,43(10): 9-12.) through adjusting acid-ether ratio, and using maleic acid-beta-cyclodextrin unit and styrene as functional monomers according to a certain proportion to participate in synthesis of polycarboxylate superplasticizer. The fluidity shows that the water reducer prepared by the method has certain mud resistance.

The Rooimen (Rooimen, research on mud resistance modification of polycarboxylate superplasticizer [ D ]. Chongqing university, 2017.) introduced dimethyl diallyl ammonium chloride in the synthesis process of the polycarboxylate superplasticizer. When a certain amount of bentonite is added into the cement, the fluidity is still good and the mud resistance effect is better than that of the traditional polycarboxylic acid water reducing agent when the amount of the bentonite reaches 5 percent.

Research on a low-temperature synthesis process of an amphoteric polycarboxylic acid water reducer with an anti-mud effect [ J ] chemical and biological engineering, 2017,34(6):45-50, 64.) in Zhao, military, and the like (Zhao, military, Shao Hua.) uses diglycolamine to prepare an unsaturated monomer through an esterification reaction, participates in the synthesis of a polycarboxylic acid water reducer, and synthesizes the amphoteric polycarboxylic acid water reducer. The net slurry fluidity experiment shows that when the mud content reaches 5%, the water reducing agent still has good dispersing capacity and a good mud resistance effect.

The preparation and performance research of the carambola green and the like (carambola green, Tang Xinde, Limin. mud-resistant amphoteric polycarboxylate superplasticizer [ J ] novel building materials, 2018,45(8): 28-30.) the polycarboxylate superplasticizer with a cationic group on a side chain is synthesized by using methacryloyloxyethyl trimethyl ammonium chloride as a functional monomer. The fluidity experiment shows that the method can adsorb cationic groups on clay particles, thereby reducing the negative effect brought by the clay.

Preparation and performance research of a polycarboxylate water reducer for high mud content in a hillock mark (the hillock mark), wherein the preparation and performance research of the polycarboxylate water reducer for high mud content [ J ] Chinese building material science and technology, 2019,28(4): 20-21.) use unsaturated phosphate (HEMAP) as a raw material to synthesize the concrete polycarboxylate water reducer for high mud content at normal temperature.

The synthesis and performance research of the Quqi Hengpeng-Zengwen-anti-mud slump-retaining type polycarboxylate water reducer [ J ] novel building material 2020,47(7): 81-85.) adopts phosphate ester functional monomer to synthesize the polycarboxylate water reducer with better mud slump-retaining effect at normal temperature.

The mud-resistant polycarboxylic acid water reducer is synthesized by using mud-resistant functional monomers, and the water reducer has good mud adaptability.

The patent "Clay inhibitor for improving the mud resistance of polycarboxylic acid water reducing agent and its application method" (application No. 201610998610.4, practice) adopts one or more of dodecyl dimethyl benzyl ammonium chloride and hexadecyl trimethyl ammonium bromide as cationic polymer monomer.

The patent 'a mud-resistant polycarboxylate water reducing agent' (application No. 201710545477.1, in the state of examination) adopts one of three functional monomers of methacryloyloxyethyl phosphate, polyfunctional acid acrylate and ethylene glycol methacrylate phosphate.

The patent of polycation anti-mud type polycarboxylate superplasticizer and a preparation method thereof (application No. 201810069085.7, in an actual examination state) adopts hydroxy acrylate to dropwise add hydrochloric acid solution of tetraethylenepentamine to prepare a cation anti-mud type monomer.

The patent "multifunctional unsaturated monomer for mud slump resistance for producing polycarboxylic acid slump retention mother liquor" (application No. 201811555794.2, entitled state) adopts unsaturated carboxylic ester of sorbitol, ethylene glycol or polyethylene glycol as mud resistance monomer.

The patent "a mud-resistant amphoteric polycarboxylate superplasticizer and a preparation method thereof" (application No. 201910347817.9, in the state of examination) adopts 6-dimethylamino-1-hexanol, methacryloyl chloride and 1, 3-propane sultone to react to generate an amphoteric monomer.

The patent "mud-resistant tannic acid based star polycarboxylic acid water reducing agent and the preparation method thereof" (application No. 202010606014.3, in practical examination) uses diallylamine modified tannic acid functional monomer, methacryloyloxyethyl trimethyl ammonium chloride or dimethyl diallyl ammonium chloride as mud-resistant functional monomer.

Patent "Anti-mud thickening slow-release polycarboxylate superplasticizer and preparation and application thereof"(application No. 202110844063.5, published state), trimethylolpropane and acrylic acid compound are used for esterification reaction to synthesize the mud-resistant functional monomer, and 1,2, 6-hexanetriol and itaconic acid compound are used for esterification reaction to synthesize the mud-resistant functional monomer.

In conclusion, the existing polycarboxylate superplasticizers have more mud-resistant means, and the number of related documents and patents is also considerable. However, the preparation method generally has the defects and disadvantages of higher preparation cost, limited mud slump retaining effect or single action effect and the like.

Disclosure of Invention

Aiming at the defect that the polycarboxylic acid water reducing agent is sensitive to the content of mud in sand, the invention provides a mud-resistant polycarboxylic acid water reducing agent mother liquor, which can obviously improve the mud resistance of the polycarboxylic acid water reducing agent.

The mud-resistant polycarboxylate superplasticizer mother liquor is prepared by the following steps: preparing a prepolymer from prenyl polyoxyethylene ether and dicarboxylic acid ester, and polymerizing methyl allyl polyoxyethylene ether, the prepolymer, acrylic acid and tetraethyleneglycol diacrylate to obtain a polycarboxylic acid water reducer mother liquor.

Specifically, the mud-resistant polycarboxylate superplasticizer mother liquor is prepared by the following steps:

step one, preparation of prepolymer

1) Stirring and heating dicarboxylic acid ester to the beginning of reflux, wherein the dicarboxylic acid ester is one or more of dimethyl malonate, diethyl malonate and dipropyl malonate;

2) continuously heating to 40-60 ℃, adding a polymerization inhibitor and stirring, wherein the polymerization inhibitor is one or a mixture of any more of phenothiazine, 2-tert-butylhydroquinone and hydroquinone;

3) then heating to 70-100 ℃, and then adding prenyl polyoxyethylene ether;

4) then adding a catalyst, wherein the catalyst is one of potassium hydroxide, sodium methoxide, dibutyltin oxide or strongly basic anion exchange resin;

5) continuously heating to 100-150 ℃, and preserving heat for 1-7 hours;

6) then cooling to below 60 ℃, and discharging to obtain a prepolymer;

wherein the mass ratio of the prenyl alcohol polyoxyethylene ether, the dicarboxylic ester, the polymerization inhibitor and the catalyst added in the steps 1) -4) is 100: 2-12: 0.1-0.8: 2-12;

step two, preparation of water reducer mother liquor

7) Mixing the prepolymer prepared in the first step, methyl allyl polyoxyethylene ether and deionized water according to the mass ratio of 20-30: 320-360: 300-320, and stirring at normal temperature until the prepolymer and the methyl allyl polyoxyethylene ether are completely dissolved to prepare a base solution;

8) continuously adding hydrogen peroxide and uniformly stirring;

9) preparing a solution A and a solution B,

wherein, the liquid A comprises 1.0 to 1.4 parts of mercaptopropionic acid, 0.4 to 1.0 part of vitamin C and 85 to 90 parts of deionized water by mass, the liquid B comprises 30 to 35 parts of acrylic acid, 5 to 10 parts of tetraethyleneglycol diacrylate and 40 to 45 parts of deionized water by mass,

simultaneously dripping the solution A and the solution B into the base solution obtained in the step 7) to obtain a base solution of the water reducing agent, wherein the mass ratio of the solution A to the solution B to the hydrogen peroxide to the base solution is 86-93: 75-90: 2-5: 640 to 710;

10) and then supplementing water and adjusting the pH value to 6-7 to obtain the anti-mud polycarboxylate superplasticizer mother liquor.

Preferably, the mass ratio of the prenyl alcohol polyoxyethylene ether to the dicarboxylic ester to the polymerization inhibitor to the catalyst is 100: 4-10: 0.2-0.6: 4 to 9.

Preferably, the molecular weight of the prenyl alcohol polyoxyethylene ether in the step 3) is 800-2000.

Preferably, the molecular weight of the methallyl polyoxyethylene ether in the step 7) is 2000-3000.

The mud-resistant polycarboxylate superplasticizer mother liquor prepared by the method disclosed by the invention is added when concrete is prepared, so that the mud resistance, slump retaining performance and slow release performance of the concrete can be effectively improved. Namely, the mud-resistant polycarboxylate superplasticizer mother liquor prepared by the method has mud resistance, slump loss resistance and slow release performance, and can also obviously improve the workability of concrete.

The method is clearly proposed by examining relevant documents and patents, and no data is found, so the method has obvious innovation. Compared with the prior art, the invention has the remarkable innovation: (1) the raw materials are different. The method uses dicarboxylic acid ester to perform ester exchange reaction with prenyl polyoxyethylene ether to obtain prepolymer, and then performs polymerization reaction with acrylic acid and tetraethyleneglycol diacrylate. The prepolymer and the tetraethyleneglycol diacrylate ester both have 2 double bonds, and the prepolymer and the tetraethyleneglycol diacrylate ester are matched to obtain a more reasonable reticular cross-linked structure, so that the mud resistance effect is better. (2) The process is different. Firstly, obtaining a prepolymer by adopting bulk polymerization, and then obtaining the anti-mud polycarboxylate superplasticizer molecules by adopting solution polymerization. (2) And (4) multi-functionalization. The polycarboxylate superplasticizer polymerized by the method not only has obvious mud resistance effect, but also can endow concrete with better workability.

The invention has the beneficial effects that:

1. the production process has strong operability and is suitable for industrial production.

2. The mud resistance effect is good: the mother liquor formula can be adjusted according to the actual mud content in the sand, and the method has a good effect on montmorillonite clay.

3. The workability of concrete can be obviously improved.

4. Common chemical raw materials are adopted, and the cost is relatively low.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is a schematic diagram showing the influence of mother liquor of different polycarboxylic acid water reducing agents on the fluidity of clay-containing cement paste.

FIG. 2 is an XRD diagram of montmorillonite treated by different polycarboxylate superplasticizer mother liquids.

Detailed Description

The present invention will now be described in more detail with reference to the accompanying drawings, in which preferred embodiments of the invention are shown, it being understood that one skilled in the art may modify the invention herein described while still achieving the beneficial results of the present invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.

In order to make the objects and features of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is noted that the drawings are in greatly simplified form and that non-precision ratios are used for convenience and clarity in aiding in the description of the embodiments of the invention. In addition, in the practical application process, the production method of the mud-resistant polycarboxylate superplasticizer mother liquor comprises two steps, namely preparation of the prepolymer and synthesis of the polycarboxylate superplasticizer mother liquor.

Example 1

1. Preparation of prepolymer 1:

1) adding 15 g of dimethyl malonate into a 500mL three-neck flask, starting stirring, starting heating, and starting refluxing;

2) heating to 50 ℃, adding 0.9 g of phenothiazine, and stirring for 5 minutes;

3) then raising the temperature to 75 ℃, and adding 300 g of isopentenol polyoxyethylene ether (with the molecular weight of 800);

4) adding 12 g of potassium hydroxide;

5) heating to 120 ℃, and preserving heat for 3 hours;

6) then cooling to below 60 ℃, and discharging to obtain prepolymer 1;

2. synthesis of a water reducing agent mother liquor 1:

1) 340 g of methyl allyl polyoxyethylene ether (molecular weight 2400), 20 g of prepolymer 1 and 300 g of deionized water are added into a 1000mL three-neck flask, and stirred for 20 minutes at normal temperature to ensure that the methyl allyl polyoxyethylene ether is completely dissolved.

2) 5g of hydrogen peroxide (with the concentration of 27.5%) is added and stirred for 5 minutes.

3) And preparing solution A and solution B. Solution A: 1.4 grams mercaptopropionic acid, 0.8 grams vitamin C, 85 grams deionized water. And B, liquid B: 35 grams of acrylic acid, 5 grams of tetraethyleneglycol diacrylate, 40 grams of deionized water. And (3) adding the solution A and the solution B into a 1000mL three-neck flask in a dropwise manner, wherein the solution A is dropwise added for 3 hours, and the solution B is dropwise added for 2.5 hours.

4) After 1 hour of dripping, water is added to 1000 g.

5) And (3) neutralizing with sodium hydroxide until the pH value is 6-7 to obtain the mother liquor 1 of the water reducing agent.

Example 2

1. Preparation of prepolymer 2:

1) adding 18 g of diethyl malonate into a 500mL three-neck flask, starting stirring, starting heating, and starting refluxing;

2) after heating to 50 ℃, adding 1.2g of 2-tert-butylhydroquinone, and stirring for 5 minutes;

3) then raising the temperature to 85 ℃, and adding 300 g of prenyl polyoxyethylene ether (molecular weight is 1000);

4) 15 g of sodium methoxide is added;

5) heating to 130 ℃, and keeping the temperature for 4 hours;

6) then cooling to below 60 ℃, and discharging to obtain prepolymer 2;

2. and (3) synthesis of a water reducing agent mother liquor 2:

1) 335 g of methyl allyl polyoxyethylene ether (molecular weight 2400), 25 g of prepolymer 2 and 310 g of deionized water are added into a 1000mL three-neck flask, and stirred for 20 minutes at normal temperature to ensure that the methyl allyl polyoxyethylene ether is completely dissolved.

2) 4 g of hydrogen peroxide (with the concentration of 27.5%) is added and stirred for 5 minutes.

3) And preparing solution A and solution B. Solution A: 1.2g mercaptopropionic acid, 0.6 g vitamin C, 87g deionized water. And B, liquid B: 33 grams of acrylic acid, 7 grams of tetraethyleneglycol diacrylate, 42 grams of deionized water. And (3) adding the solution A and the solution B into a 1000mL three-neck flask in a dropwise manner, wherein the solution A is dropwise added for 3 hours, and the solution B is dropwise added for 2.5 hours.

4) After 1 hour of dripping, water is added to 1000 g.

5) And (4) neutralizing with sodium hydroxide until the pH value is 6-7 to obtain a water reducing agent mother liquor 2.

Example 3

1. Preparation of prepolymer 3:

1) adding 21 g of dipropyl malonate into a 500mL three-neck flask, starting stirring, starting heating, and starting refluxing;

2) heating to 60 ℃, adding 1.2g of hydroquinone, and stirring for 5 minutes;

3) then raising the temperature to 90 ℃, and adding 300 g of prenyl polyoxyethylene ether (with the molecular weight of 1200);

4) adding 20 g of dibutyltin oxide;

5) heating to 140 ℃, and preserving heat for 3.5 hours;

6) then cooling to below 60 ℃, and discharging to obtain prepolymer 3;

2. and (3) synthesis of a water reducing agent mother liquor:

1) 330 g of methyl allyl polyoxyethylene ether (molecular weight of 2400), 30 g of prepolymer 3 and 320 g of deionized water are added into a 1000mL three-neck flask, and the mixture is stirred for 20 minutes at normal temperature to ensure that the methyl allyl polyoxyethylene ether is completely dissolved.

3) And preparing solution A and solution B. Solution A: 1.1 g mercaptopropionic acid, 0.5 g vitamin C, 88 g deionized water. And B, liquid B: 30 grams of acrylic acid, 10 grams of tetraethyleneglycol diacrylate, 44 grams of deionized water. And (3) adding the solution A and the solution B into a 1000mL three-neck flask in a dropwise manner, wherein the solution A is dropwise added for 3 hours, and the solution B is dropwise added for 2.5 hours.

4) After 1 hour of dripping, water is added to 1000 g.

5) And (4) neutralizing with sodium hydroxide until the pH value is 6-7 to obtain a water reducing agent mother liquor 3.

Synthesis of mother liquor of reference water reducing agent

In order to verify the performance of the polycarboxylate superplasticizer mother liquor, a reference polycarboxylate superplasticizer mother liquor is synthesized to be used as a blank sample for comparison, and the mother liquor does not contain prepolymer and tetraethyleneglycol diacrylate.

The synthesis method comprises the following steps:

1) 360 g of methyl allyl polyoxyethylene ether (molecular weight of 2400) and 340 g of deionized water are added into a 1000mL three-neck flask, and the mixture is stirred for 20 minutes at normal temperature to ensure that the methyl allyl polyoxyethylene ether is completely dissolved.

3) And preparing solution A and solution B. Solution A: 1.4 g mercaptopropionic acid, 0.6 g vitamin C, 85 g deionized water. And B, liquid B: 40 grams of acrylic acid, 40 grams of deionized water. And (3) adding the solution A and the solution B into a three-neck flask in a dropwise manner, wherein the solution A is dropwise added for 3 hours, and the solution B is dropwise added for 2.5 hours.

4) After 1 hour of complete dripping, water is added to 1000 g.

5) And (4) neutralizing with sodium hydroxide until the pH value is 6-7 to obtain the mother liquor of the reference water reducing agent.

Test effect verification

(1) Degree of fluidity of the paste

Carrying out a net slurry test according to GB/T8077-2012 'concrete admixture homogeneity test method', wherein the net slurry ratio is as follows: 295g of ordinary portland cement, 5g of montmorillonite, 87g of water and 1.2g of water reducer mother liquor. The fluidity at the beginning of the net slurry, at 30 minutes and at 60 minutes was measured and the test results are shown in FIG. 1. The water reducer mother liquor 1, the water reducer mother liquor 2, the water reducer mother liquor 3 and the reference water reducer mother liquor are the same in solid content of the water reducer mother liquor synthesized in the embodiment, and therefore, the water reducer mother liquor has comparability.

The results in FIG. 1 show that the initial fluidity of the mother liquors of the respective water reducing agents is not very different. However, at 30 minutes and 60 minutes, the fluidity of the water reducer mother liquor 1, the water reducer mother liquor 2 and the water reducer mother liquor 3 is obviously higher than that of the reference water reducer mother liquor, which indicates that the mud resistance of the three mother liquors is obviously higher than that of the reference water reducer mother liquor. Wherein, the mud-resistant effect of the mother liquor 3 of the water reducing agent is relatively optimal.

(2) Interlayer spacing of montmorillonite

Pouring 2g of montmorillonite into a beaker filled with 48g of deionized water, and uniformly stirring by using a glass rod to obtain a blank group; pouring 2g of the weighed reference water reducing agent mother liquor and 2g of montmorillonite into a beaker filled with 46g of deionized water, stirring by using a glass rod, and marking as a reference group; 2g of water reducer mother liquor 1, 2g of water reducer mother liquor and 3 g of water reducer mother liquor are respectively added into a beaker containing 2g of montmorillonite and 46g of deionized water, and are uniformly stirred by a glass rod and are respectively marked as experiment group 1, experiment group 2 and experiment group 3. And then placing the solution in a constant-temperature water bath kettle, heating and oscillating for 1h, setting the temperature to be 25 ℃, and then centrifuging by using a centrifugal machine, wherein the parameter is set to be 4000r/min, and the time is 10 min. And taking the lower precipitate after the centrifugation is finished, and drying to constant weight. After the drying, the precipitate was ground into fine powder in a mortar using a mortar and pressed into a sheet-like sample to be measured.

As can be seen in FIG. 2, d of montmorillonite₀₀₁The surface diffraction peak 2 theta is 6.50 degrees, and after the surface diffraction peak acts on the reference water reducing agent mother liquor, the water reducing agent mother liquor 1, the water reducing agent mother liquor 2 and the water reducing agent mother liquor 3, the d of the montmorillonite is₀₀₁The plane diffraction peaks 2 θ all shifted to the low angle direction, which are 5.94 °, 6.16 °, 6.24 ° and 6.32 °, respectively.

The interlamellar spacings of the above-described mother liquor-treated montmorillonite were calculated to be 1.45nm, 1.40nm, 1.38nm and 1.36nm, respectively, according to Bragg equation 2dsin θ = n λ, as shown in table 1.

TABLE 1 interlamellar spacing after treatment of montmorillonite with different water reducing agent mother liquors

Group of	Sample (I)	2θ(˚)	Interlayer spacing/nm
				Blank group	Montmorillonite and deionized water	6.50	1.32
Reference group	Montmorillonite + reference water reducing agent mother liquor	5.94	1.45
				Experimental group 1	Montmorillonite + water reducing agent mother liquor 1	6.16	1.40
Experimental group 2	Montmorillonite + water reducing agent mother liquor 2	6.24	1.38
				Experimental group 3	Montmorillonite + water reducing agent mother liquor 3	6.32	1.36

The interlayer spacing of the blank montmorillonite group is 1.32nm, and the interlayer spacing is increased to a certain extent after the montmorillonite is treated by the water reducing agent mother liquor. The reason is that the polyether long chain of the polycarboxylic acid water reducing agent can enter the montmorillonite layer to generate intercalation adsorption, so that the interlayer distance of the montmorillonite is increased. When the water reducing agent has a strong mud resistance effect, a part of polyether long chains still enter the montmorillonite layers, so that the interlayer spacing of the montmorillonite treated by the water reducing agent is larger than that of the blank montmorillonite, but the increase amplitude can be reduced.

The results in table 1 show that although the interlayer distance of the montmorillonite treated by the water reducer mother liquor 1, the water reducer mother liquor 2 and the water reducer mother liquor 3 is higher than that of the blank montmorillonite, the interlayer distance of the montmorillonite treated by the reference water reducer mother liquor is significantly lower, which indicates that the water reducer mother liquor 1, the water reducer mother liquor 2 and the water reducer mother liquor 3 have better mud resistance compared with the reference water reducer mother liquor.

In addition, table 1 also shows that the water reducing agent mother liquor 3 has the optimal mud resistance effect, which is consistent with the above net slurry test result.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The mud-resistant polycarboxylate superplasticizer mother liquor is characterized by being prepared by the following steps:

step one, preparation of prepolymer

2) continuously heating to 40-60 ℃, adding a polymerization inhibitor which is one or a mixture of any more of phenothiazine, 2-tert-butylhydroquinone and hydroquinone, and stirring;

3) then heating to 70-100 ℃, and then adding isoamylene alcohol polyoxyethylene ether;

5) continuously heating to 100-150 ℃, and preserving heat for 1-7 hours;

6) then cooling to below 60 ℃, and discharging to obtain a prepolymer;

step two, preparation of water reducer mother liquor

8) continuously adding hydrogen peroxide and uniformly stirring;

9) preparing a solution A and a solution B,

and (3) simultaneously dripping the solution A and the solution B into the base solution obtained in the step 7) to obtain a base solution of the water reducing agent, wherein the mass ratio of the solution A to the solution B to the hydrogen peroxide to the base solution is 86-93: 75-90: 2-5: 640 to 710;

2. The mud-resistant polycarboxylate superplasticizer mother liquor as claimed in claim 1, wherein the mass ratio of the prenyl alcohol polyoxyethylene ether, the dicarboxylic ester, the polymerization inhibitor and the catalyst is 100: 4-10: 0.2-0.6: 4 to 9.

3. The mud-resistant polycarboxylate superplasticizer mother liquor as claimed in claim 1, wherein the molecular weight of said prenyl polyoxyethylene ether in step 3) is 800-2000.

4. The mud-resistant polycarboxylate superplasticizer mother liquor as claimed in claim 1, wherein said methyl allyl polyoxyethylene ether in step 7) has a molecular weight of 2000-3000.