阅读说明：本技术 一种抗泥功能单体、抗泥型聚羧酸减水剂及制备方法和应用 (Anti-mud functional monomer, anti-mud polycarboxylic acid water reducer, and preparation method and application thereof ) 是由 文轩 汪源 汪苏平 胡志豪 于 2021-09-03 设计创作，主要内容包括：本发明公开了一种抗泥功能单体、抗泥型聚羧酸减水剂及制备方法和应用,属于建筑材料混凝土外加剂领域,抗泥功能单体由如下重量份的原料制成：不饱和芳香族物质100～130份、不饱和胺类120～140份、硅烷偶联剂1～2.5份；所述不饱和芳香族物质为丙烯酸苄酯和OPPEA中的至少一种,所述不饱和胺类为烯丙胺和5-氨基乙酰丙酸,其中,烯丙胺和5-氨基乙酰丙酸的重量比为(3～12)：1；本发明的抗泥功能单体能够有效提高聚羧酸减水剂的抗泥、保坍性能；通过引入不饱和芳香族物质丙烯酸苄酯和OPPEA以增大聚羧酸减水剂侧链的空间位阻,通过不饱和胺类在泥土表面及隔层中形成保护层；二者共同作用避免聚羧酸减水剂侧链插入到泥土中,提高聚羧酸减水剂的抗泥、保坍性能。(The invention discloses a mud-resistant functional monomer, a mud-resistant polycarboxylate superplasticizer, a preparation method and application thereof, belonging to the field of building material concrete admixtures, wherein the mud-resistant functional monomer is prepared from the following raw materials in parts by weight: 100-130 parts of unsaturated aromatic substances, 120-140 parts of unsaturated amines and 1-2.5 parts of silane coupling agents; the unsaturated aromatic substance is at least one of benzyl acrylate and OPPEA, the unsaturated amine is allylamine and 5-aminolevulinic acid, and the weight ratio of the allylamine to the 5-aminolevulinic acid is (3-12): 1; the mud-resistant functional monomer can effectively improve the mud-resistant and slump-retaining performances of the polycarboxylic acid water reducer; unsaturated aromatic substance benzyl acrylate and OPPEA are introduced to increase the steric hindrance of a side chain of the polycarboxylate superplasticizer, and a protective layer is formed on the soil surface and in the interlayer through unsaturated amines; the side chain of the polycarboxylate superplasticizer is prevented from being inserted into soil under the combined action of the two, and the mud resistance and slump retaining performance of the polycarboxylate superplasticizer are improved.)

1. The anti-mud functional monomer is characterized by being prepared from the following raw materials in parts by weight: 100-130 parts of unsaturated aromatic substances, 120-140 parts of unsaturated amines and 1-2.5 parts of silane coupling agents;

the unsaturated aromatic substance is at least one of benzyl acrylate and OPPEA, the unsaturated amine is allylamine and 5-aminolevulinic acid, and the weight ratio of the allylamine to the 5-aminolevulinic acid is (3-12): 1.

2. the monomer as claimed in claim 1, wherein the silane coupling agent is at least one of vinyltriethoxysilane and gamma-methacryloxypropyltrimethoxysilane.

3. The method for preparing the anti-mud functional monomer according to claim 1 or 2, which is characterized by comprising the following steps:

s1, adding an unsaturated aromatic substance, a solvent and an initiator into a reaction vessel, and stirring to uniformly disperse the unsaturated aromatic substance, the solvent and the initiator;

s2, heating to 35-45 ℃, and adding unsaturated amines;

s3, heating to 50-60 ℃, and adding a silane coupling agent;

and S4, reacting for 1-2 h at the temperature of 75-80 ℃, and then cooling to room temperature to obtain the anti-mud functional monomer.

4. The method of claim 3, wherein in step S1, the solvent is at least one of toluene, acetone, and xylene.

5. An anti-mud type polycarboxylate water reducer characterized by comprising the anti-mud functional monomer according to claim 1 or 2.

6. The preparation method of the anti-mud type polycarboxylate superplasticizer according to claim 5, characterized by comprising the following steps:

p1, adding 365 parts of prenyl polyoxyethylene ether into a reaction container, and dissolving in 290 parts of deionized water at 40 ℃ to obtain a solution A; dissolving 0.7 part of vitamin C and 1.8 parts of mercaptopropionic acid in 65 parts of deionized water to obtain a solution B; dissolving 25 parts of acrylic acid, 15 parts of an anti-mud functional monomer and 60 parts of hydroxyethyl acrylate in 15 parts of deionized water to obtain a solution C;

p2, adding 5.2 parts of hydrogen peroxide with the mass fraction of 30% into the solution A, and uniformly stirring; then, simultaneously dripping the solution B and the solution C into the reaction container, wherein the dripping of the solution B is finished within 3.5 hours, and the dripping of the solution C is finished within 3 hours; after the solution is dripped, the solution is reacted for 1.5h at the temperature of 40 ℃, and then deionized water is added to dilute the solution until the solid content of the anti-mud polycarboxylic acid water reducing agent is 40%.

7. The application of the mud-resistant polycarboxylate water reducer as defined in claim 5 or the mud-resistant polycarboxylate water reducer prepared by the preparation method as defined in claim 6 in concrete.

Technical Field

The invention belongs to the field of building material concrete admixtures, and particularly relates to a mud-resistant functional monomer, a mud-resistant polycarboxylic acid water reducer, a preparation method and application thereof.

Background

The polycarboxylate superplasticizer (PCE) serving as a third-generation concrete superplasticizer has the characteristics of high water reducing rate, good stability, convenience in operation, environmental friendliness and the like, and is widely applied to high-performance concrete such as high-strength concrete, premixed concrete, self-compacting concrete, pump concrete and the like. However, as the foundation construction enters the golden period, the demand of the sand and the stone is increased day by day, the natural high-quality sand and stone are gradually replaced by artificial and inferior sand and stone, and the mud content in the inferior sand and stone is increased. Firstly, the PCE is very sensitive to soil, the soil in the sand and stone, particularly montmorillonite, has a great influence on the performance of the concrete added with the PCE, the over-high content of the soil can seriously influence the water reducing dispersibility of the PCE and the mixing performance of the concrete, so that the slump loss is relatively high over time, and the transportation, construction and pumping requirements of the concrete cannot be met; secondly, the excessive mud content can cause the occurrence of clay phase in the concrete structure, reduce the bonding strength between the cement and the aggregate and reduce the strength of the concrete. Therefore, how to improve the mud resistance of the polycarboxylate superplasticizer becomes an urgent problem to be solved, and the mud-resistant polycarboxylate superplasticizer is provided, which has important significance for the development of concrete admixtures and the concrete industry.

In order to find a corresponding solution to reduce the negative impact of soil, it is necessary to study the mechanism of action between soil and PCE. The reduction of concrete fluidity caused by over-high mud content is mainly attributed to four factors: firstly, soil adsorbs the surface of the PCE, so that the soil and cement form surface competitive adsorption; secondly, soil adsorbs the interlayer of the PCE, and the side chain of the PCE is easy to insert into the interlayer of soil particles to lose the dispersing activity;

at present, the research on the mud-resistant polycarboxylate superplasticizer mainly focuses on the following points: (1) introduction of phosphate functional groups: after the phosphate functional group is introduced into the polycarboxylate superplasticizer, the phosphate group is in a free state, so that on one hand, the side chain of the polycarboxylate superplasticizer can be effectively prevented from being inserted into soil by utilizing larger steric hindrance of the phosphate functional group; on the other hand, the adsorption capacity of the phosphate group is better than that of the carboxyl group, so that the adsorption of the polycarboxylate water reducing agent on soil can be reduced, and the sensitivity of the soil to the polycarboxylate water reducing agent is reduced. (2) Introducing nitrogen-containing functional group and cationic functional group substances: as is known, the montmorillonite is electronegative, and substances containing nitrogen functional groups and cation functional groups can be adsorbed on the surface of the montmorillonite and in an interlayer to form a protective layer to inhibit the polycarboxylic acid water reducing agent from contacting with soil, so that the mud resistance effect is achieved. (3) Changing the length of a side chain of the polycarboxylate superplasticizer: the side chain of the polycarboxylate superplasticizer is comb-shaped, so that cement particles can be effectively separated, and the fluidity of concrete is increased. But the side chain is easier to insert into the aluminosilicate layer in the clay, and the effect of the water reducing agent is inhibited. Through increasing polycarboxylate water reducing agent side chain length, can effectively increase the steric hindrance of side chain, restrain its absorption on earth, improve polycarboxylate water reducing agent's anti mud performance. (4) Increasing the steric hindrance of the polycarboxylate superplasticizer: the polycarboxylate superplasticizer side chain (PEO) is composed of chain-shaped substances, and the steric hindrance is small, so that the PEO is easily adsorbed by a soil layer, and the side chain can be difficultly inserted into the soil layer by increasing the steric hindrance of polycarboxylate superplasticizer molecules, so that the effect of the superplasticizer is improved. For example, Chinese patent CN109694213A discloses a mud-resistant polycarboxylate superplasticizer and a preparation method thereof, the preparation method places beta-cyclodextrin on a side chain of the polycarboxylate superplasticizer, the characteristic that the polycarboxylate superplasticizer disperses cement particles through steric hindrance effect is shown, and the beta-cyclodextrin group is introduced into the molecular structure of the polycarboxylate superplasticizer, so that the polycarboxylate superplasticizer and clay can be prevented from forming an intercalation structure, and chemical adsorption is prevented. The mud-resistant polycarboxylate superplasticizer prepared by the preparation method can fundamentally solve the problem that the polycarboxylate superplasticizer is sensitive to mud. However, cyclodextrin has poor water solubility, long synthetic route and high cost.

Disclosure of Invention

In view of the defects of the prior art, one of the purposes of the present invention is to provide a mud-resistant functional monomer, which is added into the polycarboxylate superplasticizer mother liquor, so as to effectively reduce the sensitivity of the polycarboxylate superplasticizer to mud content and improve the mud-resistant performance of the polycarboxylate superplasticizer.

In order to achieve the purpose, the specific technical scheme of the invention is as follows:

the anti-mud functional monomer is prepared from the following raw materials in parts by weight: 100-130 parts of unsaturated aromatic substances, 120-140 parts of unsaturated amines and 1-2.5 parts of silane coupling agents;

the unsaturated aromatic substance is at least one of benzyl acrylate and polyethylene glycol o-phenylphenyl ether acrylate (OPPEA), the unsaturated amine is allylamine and 5-aminolevulinic acid, and the weight ratio of the allylamine to the 5-aminolevulinic acid is (3-12): 1.

unsaturated aromatic substances and unsaturated amines are subjected to free radical addition polymerization to prepare a mud-resistant functional monomer, and the mud-resistant functional monomer is introduced into the polycarboxylate superplasticizer molecule by utilizing the characteristics of a coupling agent; the functional monomer is introduced into the molecular structure of the polycarboxylate superplasticizer, so that the side chain of the polycarboxylate superplasticizer can be modified; on one hand, the length of the side chain of the polycarboxylate superplasticizer is increased, a benzene ring structure with large steric hindrance is introduced, and the steric hindrance of the side chain of the polycarboxylate superplasticizer PEO is increased under the combined action of the two structures, so that the polycarboxylate superplasticizer is difficult to insert into an interlayer between soil layers; on the other hand, the unsaturated amines belong to substances containing nitrogen functional groups and can inhibit the adsorption of soil on the water reducing agent; therefore, the mud-resistant functional monomer can effectively improve the mud resistance and slump retention of the polycarboxylate superplasticizer, and can still well play a role in keeping the slump and the net slurry fluidity of concrete when the mud content of sand and stone used in the concrete is high. In addition, compared with the method of introducing benzene rings through styrene, the styrene is easy to self-polymerize, the byproducts are more, the byproducts of benzyl acrylate and OPPEA are less, the length of a side chain of the polycarboxylic acid water reducing agent can be increased while the benzene rings with large steric hindrance are introduced, and the mud resistance of the mud resistance functional monomer can be improved; furthermore, benzyl acrylate and OPPEA do not have critical control over the reaction temperature.

Preferably, the silane coupling agent is at least one of vinyltriethoxysilane and gamma-methacryloxypropyltrimethoxysilane.

The invention also aims to provide a preparation method of the anti-mud functional monomer, which comprises the following steps:

s1, adding an unsaturated aromatic substance, a solvent and an initiator into a reaction vessel, and stirring to uniformly disperse the unsaturated aromatic substance, the solvent and the initiator;

s2, heating to 35-45 ℃, and adding unsaturated amines;

s3, heating to 50-60 ℃, and adding a coupling agent;

and S4, reacting for 1-2 h at the temperature of 75-80 ℃, and then cooling to room temperature to obtain the anti-mud functional monomer.

The preparation method adopts gradient temperature rise, and strictly controls the reaction to be carried out orderly.

Preferably, in step S1, the solvent is at least one of toluene, acetone, and xylene.

The third purpose of the invention is to provide an anti-mud polycarboxylic acid water reducing agent containing the functional monomer. The mud-resistant polycarboxylate superplasticizer disclosed by the invention has good slump retaining and mud-resistant performances, and can still well play a role in keeping the slump and the net slurry fluidity of concrete when the mud content of sand and stone used in the concrete is high.

The fourth purpose of the invention is to provide a preparation method of the mud-resistant polycarboxylate superplasticizer, which comprises the following steps:

p1, adding 365 parts of prenyl polyoxyethylene ether into a reaction container, and dissolving in 290 parts of deionized water at 40 ℃ to obtain a solution A; dissolving 0.7 part of vitamin C and 1.8 parts of mercaptopropionic acid in 65 parts of deionized water to obtain a solution B; dissolving 25 parts of acrylic acid, 15 parts of an anti-mud functional monomer and 60 parts of hydroxyethyl acrylate in 15 parts of deionized water to obtain a solution C;

p2, adding 5.2 parts of hydrogen peroxide with the mass fraction of 30% into the solution A, and uniformly stirring; then, simultaneously dripping the solution B and the solution C into the reaction container, wherein the dripping of the solution B is finished within 3.5 hours, and the dripping of the solution C is finished within 3 hours; after the solution is dripped, the solution is reacted for 1.5h at the temperature of 40 ℃, and then deionized water is added to dilute the solution until the solid content of the anti-mud polycarboxylic acid water reducing agent is 40%.

The fifth purpose of the invention is to provide the application of the anti-mud polycarboxylic acid water reducing agent in concrete, wherein the mixing amount of the anti-mud polycarboxylic acid water reducing agent is 1% of the cementing material.

Compared with the prior art, the invention has the advantages that:

(1) the mud-resistant functional monomer can effectively improve the mud-resistant and slump-retaining performances of the polycarboxylic acid water reducer; unsaturated aromatic substance benzyl acrylate and OPPEA are introduced to increase the steric hindrance of a side chain of the polycarboxylate superplasticizer, and a protective layer is formed on the soil surface and in the interlayer through unsaturated amines; the side chain of the polycarboxylate superplasticizer is prevented from being inserted into soil under the combined action of the two, and the mud resistance and slump retaining performance of the polycarboxylate superplasticizer are improved.

(2) The anti-mud functional monomer is introduced into the molecular structure of the polycarboxylate superplasticizer, so that the length of the side chain of the polycarboxylate superplasticizer can be increased, a benzene ring structure with large steric hindrance is introduced, and the steric hindrance of the side chain of the polycarboxylate superplasticizer is increased under the combined action of the two structures; the mud resistance effect of the polycarboxylic acid water reducing agent is improved.

(3) Compared with the method of introducing benzene rings through styrene, the styrene is easy to self-polymerize at high temperature, the byproducts are more, the byproducts of benzyl acrylate and OPPEA are less, and the prepared mud-resistant functional monomer is high in purity and good in mud-resistant effect.

(4) According to the preparation method of the anti-mud functional monomer, a polymerization inhibitor is not required to be added, so that the polymerization efficiency can be improved, and the anti-mud performance of the anti-mud functional monomer can be improved.

Drawings

FIG. 1 shows the adsorption capacity of sodium bentonite to a polycarboxylic acid water reducing agent.

Detailed Description

The technical solutions of the present invention will be described clearly and completely below, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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 fractions in the following examples and comparative examples are in parts by weight.

Example 1

The anti-mud functional monomer provided by the embodiment is prepared from the following raw materials in parts by weight: 62 parts of benzyl acrylate, 62 parts of OPPEA, 90 parts of allylamine, 30 parts of 5-aminolevulinic acid and 1.2 parts of vinyl triethoxysilane;

the preparation method of the anti-mud functional monomer of the embodiment is as follows:

s1, adding 62 parts of benzyl acrylate and 62 parts of OPPEA into a beaker, dissolving the mixture in 100 parts of toluene, stirring the mixture at normal temperature to uniformly disperse the mixture, and adding 1 part of azobisisobutyronitrile;

s2, heating to 35 ℃, adding 90 parts of allylamine and 30 parts of 5-aminolevulinic acid, and stirring for dissolving;

s3, heating to 55 ℃, adding 1.2 parts of vinyl triethoxysilane, and stirring for dissolving;

and S4, heating to 80 ℃, carrying out heat preservation reaction for 1h, then cooling to room temperature, and discharging to obtain the anti-mud functional monomer.

Example 2

The anti-mud functional monomer provided by the embodiment is prepared from the following raw materials in parts by weight: benzyl acrylate 52 parts, OPPEA78 parts, allylamine 115 parts, 5-aminolevulinic acid 10 parts, and gamma-methacryloxypropyltrimethoxysilane 1.5 parts;

the preparation method of the anti-mud functional monomer of the embodiment is as follows:

s1, adding 52 parts of benzyl acrylate and 78 parts of OPPEA into a beaker, dissolving the mixture in 100 parts of dimethylbenzene, stirring the mixture at normal temperature to uniformly disperse the mixture, and adding 1.2 parts of dibenzoyl peroxide;

s2, heating to 40 ℃, adding 115 parts of allylamine and 10 parts of 5-aminolevulinic acid, and stirring for dissolving;

s3, heating to 60 ℃, adding 1.5 parts of gamma-methacryloxypropyltrimethoxysilane, and stirring for dissolving;

and S4, heating to 80 ℃, reacting for 1.5 hours in a heat preservation manner, cooling to room temperature, and discharging to obtain the anti-mud functional monomer.

Example 3

The anti-mud functional monomer provided by the embodiment is prepared from the following raw materials in parts by weight: 10 parts of benzyl acrylate, 100 parts of OPPEA, 100 parts of allylamine, 20 parts of 5-aminolevulinic acid and 1.3 parts of vinyl triethoxysilane;

the preparation method of the anti-mud functional monomer of the embodiment is as follows:

s1, adding 10 parts of benzyl acrylate and 100 parts of OPPEA into a beaker, dissolving the mixture in 100 parts of dimethylbenzene, stirring at normal temperature to uniformly disperse the mixture, and adding 0.9 part of dibenzoyl peroxide;

s2, heating to 35 ℃, adding 100 parts of allylamine and 20 parts of 5-aminolevulinic acid, and stirring for dissolving;

s3, heating to 50 ℃, adding 1.2 parts of vinyltriethoxysilane, and stirring for dissolving;

s4, heating to 75 ℃, reacting for 2 hours under the condition of heat preservation, cooling to room temperature, and discharging to obtain the anti-mud functional monomer.

Example 4

The anti-mud functional monomer provided by the embodiment is prepared from the following raw materials in parts by weight: 125 parts of OPPEA, 110 parts of allylamine, 10 parts of 5-aminolevulinic acid and 2 parts of vinyl triethoxysilane;

the preparation method of the anti-mud functional monomer of the embodiment is as follows:

s1, adding 125 parts of OPPEA into a beaker, dissolving the OPPEA into 100 parts of mixed solvent of dimethylbenzene and methylbenzene, stirring at normal temperature to uniformly disperse the OPPEA, and adding 0.9 part of azodiisobutyronitrile;

s2, heating to 45 ℃, adding 110 parts of allylamine and 10 parts of 5-aminolevulinic acid, and stirring for dissolving;

s3, heating to 60 ℃, adding 2 parts of vinyltriethoxysilane, and stirring for dissolving;

and S4, heating to 80 ℃, reacting for 1.5 hours in a heat preservation manner, cooling to room temperature, and discharging to obtain the anti-mud functional monomer.

Example 5

The anti-mud functional monomer provided by the embodiment is prepared from the following raw materials in parts by weight: 105 parts of benzyl acrylate, 20 parts of OPPEA, 110 parts of allylamine, 10 parts of 5-aminolevulinic acid and 2 parts of vinyl triethoxysilane;

the preparation method of the anti-mud functional monomer of the embodiment is as follows:

s1, adding 105 parts of benzyl acrylate and 20 parts of OPPEA into a beaker, dissolving the mixture in 100 parts of mixed solvent of dimethylbenzene and methylbenzene, stirring at normal temperature to uniformly disperse the mixture, and adding 0.9 part of azobisisobutyronitrile;

s2, heating to 45 ℃, adding 110 parts of allylamine and 10 parts of 5-aminolevulinic acid, and stirring for dissolving;

s3, heating to 60 ℃, adding 2 parts of vinyltriethoxysilane, and stirring for dissolving;

and S4, heating to 80 ℃, reacting for 1.5 hours in a heat preservation manner, cooling to room temperature, and discharging to obtain the anti-mud functional monomer.

Comparative example 1

The anti-mud functional monomer provided by the embodiment is prepared from the following raw materials in parts by weight: 62 parts of benzyl acrylate, 62 parts of OPPEA, 30 parts of allylamine, 100 parts of 5-aminolevulinic acid and 1.2 parts of vinyl triethoxysilane;

the preparation method of the anti-mud functional monomer of the embodiment is as follows:

s1, adding 62 parts of benzyl acrylate and 62 parts of OPPEA into a beaker, dissolving the mixture in 100 parts of toluene, stirring the mixture at normal temperature to uniformly disperse the mixture, and adding 1 part of azobisisobutyronitrile;

s2, heating to 35 ℃, adding 30 parts of allylamine and 100 parts of 5-aminolevulinic acid, and stirring for dissolving;

s3, heating to 55 ℃, adding 1.2 parts of vinyl triethoxysilane, and stirring for dissolving;

and S4, heating to 80 ℃, carrying out heat preservation reaction for 1h, then cooling to room temperature, and discharging to obtain the anti-mud functional monomer.

Comparative example 2

The anti-mud functional monomer provided by the embodiment is prepared from the following raw materials in parts by weight: 115 parts of styrene, 110 parts of allylamine, 10 parts of 5-aminolevulinic acid and 2 parts of vinyl triethoxysilane;

the preparation method of the anti-mud functional monomer of the embodiment is as follows:

s1, adding 115 parts of styrene into a beaker, dissolving the styrene into 100 parts of mixed solvent of dimethylbenzene and methylbenzene, stirring at normal temperature to uniformly disperse the styrene, and adding 0.9 part of azodiisobutyronitrile;

s2, heating to 45 ℃, adding 110 parts of allylamine and 10 parts of 5-aminolevulinic acid, and stirring for dissolving;

s3, heating to 60 ℃, adding 2 parts of vinyltriethoxysilane, and stirring for dissolving;

and S4, heating to 80 ℃, reacting for 1.5 hours in a heat preservation manner, cooling to room temperature, and discharging to obtain the anti-mud functional monomer.

Test examples

The mud-resistant functional monomer of the embodiment and the comparative example is used for preparing the polycarboxylic acid water reducer, and the preparation method comprises the following steps:

p1, adding 365 parts of prenyl polyoxyethylene ether into a four-neck flask provided with a stirrer, a thermometer and a dropping device, and dissolving in 290 parts of deionized water at 40 ℃ to obtain a solution A; dissolving 0.7 part of vitamin C and 1.8 parts of mercaptopropionic acid in 65 parts of deionized water to obtain a solution B; dissolving 25 parts of acrylic acid, 15 parts of an anti-mud functional monomer and 60 parts of hydroxyethyl acrylate in 15 parts of deionized water to obtain a solution C;

p2, adding 5.2 parts of hydrogen peroxide with the mass fraction of 30% into the solution A, uniformly stirring, then simultaneously dropwise adding the solution B and the solution C into a four-neck flask, wherein the dropwise adding of the solution B is finished within 3.5 hours, and the dropwise adding of the solution C is finished within 3 hours; after the solution is dripped, the solution is reacted for 1.5h at the temperature of 40 ℃, and then deionized water is added to dilute the solution until the solid content of the anti-mud polycarboxylic acid water reducing agent is 40%.

(1) Influence of mud-resistant polycarboxylate superplasticizer on fluidity of cement paste

According to the regulation of GB/T8077-2012 concrete admixture homogeneity test method, the anti-mud polycarboxylic acid water reducer prepared by the anti-mud functional monomer of the embodiment and the comparative example is doped into the cement paste; the cement is P.O 42.5 Xinxin reference cement, wherein the cement mixing amount is 291g, the sodium bentonite is 9g, the water mixing amount is 87g, the anti-mud polycarboxylic acid water reducer mixing amount is 3g, and the fluidity of the cement paste is tested; and compared with a commercial mud-resistant polycarboxylate superplasticizer (model HL-12), the commercial mud-resistant polycarboxylate superplasticizer is taken as a comparative example 3, and the experimental results are shown in Table 1.

TABLE 1 Cement paste fluidity (mm)

Group of	Initial	15min	30min	45min	60min
						Example 1	250	240	235	235	230
Example 2	245	245	240	230	225
						Example 3	250	245	245	240	240
Example 4	250	245	235	235	230
						Example 5	250	240	235	230	225
Comparative example 1	250	250	240	220	200
						Comparative example 2	250	235	215	200	180
Comparative example 3	245	225	205	190	185

From the experimental results, compared with the polycarboxylic acid water reducer of the comparative example, the mud-resistant polycarboxylic acid water reducer prepared from the mud-resistant functional monomer of the embodiments 1-5 has better mud resistance, and the loss of fluidity after 1 hour is 25mm at most; the weight ratio of allylamine and 5-aminolevulinic acid of comparative example 1 is out of the range of the present invention, and the loss of fluidity after 1 hour reaches 50mm, because too much 5-aminolevulinic acid is added, which results in incomplete polymerization of the energy group of the nitrogen-containing tube and reduced mud resistance of the mud resistant functional monomer; comparative example 2 adopts styrene instead of benzyl acrylate and OPPEA, and the fluidity loss after 1h reaches 70mm, because the styrene is easy to generate self-polymerization under the high-temperature condition, so that the mud resistance of the mud resistant functional monomer is reduced; comparative example 3a commercial anti-mud polycarboxylate superplasticizer was used, and the fluidity loss after 1h reached 60 mm.

(2) Influence of mud-resistant polycarboxylate superplasticizer on slump retaining performance of concrete

The anti-mud polycarboxylate superplasticizer prepared from the anti-mud functional monomers of the embodiment and the comparative example of the invention and the commercially available anti-mud polycarboxylate superplasticizer (model HL-12) are mixed into concrete, the commercially available anti-mud polycarboxylate superplasticizer is used as the comparative example 3, the mixing ratio of the concrete is shown in Table 2, and the mixing amount of the polycarboxylate superplasticizer accounts for 1% of the gelled material.

TABLE 2 showsC35 concrete mixing ratio (kg/m)³)

Reference numerals	Cement	Fly ash	River sand	Crushing stone	Water (W)
						C35	300	100	825	1010	170

Wherein the cement is P.O 42.5 Xinxin reference cement; the fly ash is II-grade fly ash; the fineness modulus of the river sand is 2.5; the crushed stone is 5-30 mm continuous graded crushed stone; the water is tap water.

The slump retention performance of fresh concrete using examples, comparative examples and a commercially available mud-resistant polycarboxylic acid water reducing agent was tested according to the relevant specifications of GB/T50080-2016 concrete mixture Performance test method Standard, and the compressive strengths of concrete 7d and 28d were measured according to the specifications of GB/T50081-2002 common concrete mechanical Properties test method Standard, with the test results shown in Table 3.

TABLE 3 concrete Performance test results

From the above test experiment results, it can be seen that: compared with the anti-mud polycarboxylic acid water reducer of the comparative example, the anti-mud polycarboxylic acid water reducer of the embodiments 1 to 5 of the invention has better slump retaining performance, and further shows that the anti-mud polycarboxylic acid water reducer prepared by the anti-mud functional monomer of the invention has good anti-mud effect. As can be seen from the experimental results, the weight ratio of allylamine to 5-aminolevulinic acid of comparative example 1 is out of the range of the invention, and the slump loss of 1h reaches 40mm, because too much 5-aminolevulinic acid is added, so that the energy groups of the nitrogen-containing tube are not completely polymerized, and the mud resistance of the mud resistant functional monomer is reduced; comparative example 2, styrene is used to replace benzyl acrylate and OPPEA, slump loss occurs after 30min, and the slump loss reaches 55mm after 1h, because styrene is easy to self-polymerize at the temperature of over 75 ℃, the mud resistance of the mud resistant functional monomer is reduced; comparative example 3 adopts a commercial anti-mud polycarboxylate superplasticizer, slump loss occurs after 30min, and the slump loss after 1h reaches 45 mm; the anti-mud polycarboxylic acid water reducing agent disclosed by the embodiments 1-5 of the invention has no slump loss after 30min, and the slump loss after 1h is only 10-15 mm; the mud-resistant polycarboxylate superplasticizers of the embodiments 1 to 5 of the invention have better mud resistance than the prior art.

(3) Adsorption capacity of soil to polycarboxylate superplasticizer

The adsorption amount of soil to the mud-resistant polycarboxylate superplasticizer (model HL-12) in example 3 and in the market is studied, the commercial mud-resistant polycarboxylate superplasticizer is used as a comparative example 3, and the mud-resistant polycarboxylate superplasticizer which is not added is used as a blank group; the experimental method is as follows: dissolving 5g of nano bentonite solution in 200g of deionized water by stirring, adjusting the pH to 12 by using sodium hydroxide, and adding 5g of a mud-resistant polycarboxylic acid water reducing agent with the solid content of 40%; then, the sodium bentonite is filtered to obtain the treated sodium bentonite, and the adsorption capacity of the sodium bentonite to the polycarboxylic acid water reducing agent is tested by utilizing thermogravimetric gravity TG, and the result is shown in figure 1. As can be seen from FIG. 1, the adsorption capacity of the nano bentonite to the commercial mud-resistant polycarboxylate water reducer (comparative example 3) is greater than that of example 3, thereby illustrating that the mud-resistant functional monomer of the invention can be used for preparing the polycarboxylate water reducer to have good mud-resistant performance.

In conclusion, the mud-resistant functional monomer can effectively improve the mud-resistant and slump-retaining performances of the polycarboxylic acid water reducer.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.