High-adaptability polycarboxylic acid water reducing agent and preparation method thereof

Abstract

The application discloses a kind of high adaptability polycarboxylate water-reducing agent and preparation method thereof.The high adaptability polycarboxylate water-reducing agent is obtained by intermediate C obtained by amidation / imide reaction of compound A and compound B, intermediate C is copolymerized with monomer D, monomer E, monomer F again;The compound A is amino polyether, the compound B is thiol-containing carboxylic acid, the monomer D is unsaturated carboxylic acid, the monomer E is styrene small monomer, and the monomer F is polymerizable phosphonic acid group monomer.The high adaptability polycarboxylate water-reducing agent product prepared by the application has the advantages of low dosage, high water-reducing rate, small slump loss, wide cement adaptability, wide sand and gravel mud content adaptation range and the like.The method of the application has the advantages of easy to obtain raw materials, simple production process, high yield, low production cost and small environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of concrete admixtures in building materials, specifically to a highly adaptable polycarboxylate superplasticizer and its preparation method. Background Technology

[0002] Polycarboxylate superplasticizers, as a type of concrete admixture, have advantages such as high water reduction rate, good slump retention, low shrinkage rate, and moderate air entrainment. In particular, their ability to adjust the molecular structure according to different application requirements has led to their widespread application in the production and preparation of modern concrete, making them a research hotspot in the field of concrete admixtures.

[0003] Currently, the shortage of concrete raw materials, the overall decline in quality, and the variability of raw materials, along with the increasing use of manufactured sand, have exacerbated the compatibility issues between polycarboxylate superplasticizers and concrete raw materials. These issues include slow early dispersion, rapid loss, excessive superplasticizer dosage, and significant adverse growth. The compatibility between polycarboxylate superplasticizers and concrete raw materials directly affects the final quality of the concrete, which in turn relates to the stability and durability of the main structure of the project. If the superplasticizer is incompatible with the concrete raw materials during the concrete manufacturing process, inferior concrete will be used to pour the main structure of the project, ultimately resulting in the main structure failing to meet expectations in terms of load-bearing capacity, and leading to risks such as deformation and collapse after construction or delivery. Therefore, controlling the effectiveness of polycarboxylate superplasticizers is directly related to the quality of concrete. Furthermore, polycarboxylate superplasticizers not only have compatibility issues with concrete raw materials but also exhibit different performance characteristics with different concrete raw materials.

[0004] Patent CN102532558A reports a synthetic method employing a pre-polymerization followed by functionalization approach. First, a carboxyl-containing polymer backbone is formed. Then, branches are introduced by grafting with terminal amino polyethers and polyethylene glycol monoalkyl ethers at a specific temperature through amidation and esterification reactions. This yields a polycarboxylic acid-based water-reducing agent whose backbone is linked by both amide / imide bonds and ester bonds. However, the esterification reaction is reversible and has a slow reaction rate.

[0005] Patent CN102993430B describes the reaction of alkenyl glycidyl ether and alkyl-terminated amino polyether to obtain an intermediate for a high-strength water-reducing agent. The intermediate is then reacted with unsaturated carboxylic acids and / or unsaturated carboxylates to obtain the high-strength water-reducing agent. Patent CN107652405A describes the synthesis of a polycarboxylic acid water-reducing agent by amide / imide-forming an amino-terminated polyether amine, followed by copolymerization with an active monomer. The water-reducing agent obtained by this preparation method has a traditional comb-like structure, thus its performance improvement has reached a bottleneck.

[0006] Patent US20050228142A1 discloses a block polycarboxylic acid polymer, prepared by atom transfer radical polymerization of a polyether macromonomer and an unsaturated acid. Patent CN107337771B discloses a triblock polycarboxylic acid superplasticizer, in which the ends of the two blocks are adsorbed groups, and the middle block is a long side chain. The adsorbed groups at the ends include carboxylic acid groups and sulfonic acid groups. This triblock polycarboxylic acid superplasticizer is prepared by reversible addition-fragmentation chain transfer polymerization. Both of these methods belong to controlled radical polymerization, which requires harsh reaction conditions and suffers from the disadvantages of difficult and expensive chain transfer agent preparation. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the present invention aims to overcome the poor adaptability of traditional comb-shaped polycarboxylate in concrete raw materials, such as slow early dispersion, excessive loss, excessive water-reducing agent dosage, and significant reverse growth. It provides a highly adaptable polycarboxylate water-reducing agent and its preparation method that has readily available raw materials, simple production process, high yield, low production cost, and low environmental pollution.

[0008] This invention provides a highly adaptable polycarboxylate superplasticizer, which is obtained by an amide / imide reaction of compound A and compound B, and then by copolymerization of intermediate C with monomers D, E and F.

[0009] The molar ratio of compound A to compound B is 1:1.05 to 1:2;

[0010] The molar ratio of intermediate C to monomers D, E, and F satisfies: C / (D+E+F)=1 / 1~1 / 7, monomers D and F are mixed in any proportion, and the molar ratio of monomer E to monomers D and F satisfies: E / (D+F)=1 / 100~1 / 4.

[0011] Compound A is an amino polyether, represented by general formula (Ⅰ):

[0012]

[0013] In the formula, x and z are the average molar additions of polyoxypropylene (PO), each independently chosen from 1 to 20, and (x+z)≤50; y is the average molar addition of polyoxyethylene (EO), which is from 1 to 50.

[0014] The compound B is a thiol-containing carboxylic acid, specifically selected from any one or more of thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and L-2-amino-3-mercaptopropionic acid, but not limited thereto;

[0015] The monomer D is an unsaturated carboxylic acid, represented by the general formula (II):

[0016]

[0017] In formula (II), R1 is H or CH3, and R2 is H or m is an integer satisfying 0 ≤ m ≤ 3; when R2 is When it reacts with COOM1 in general formula (II) to form an anhydride; M1 is H, alkali metal ion, 1 / 2 alkaline earth metal ion, ammonium ion or organic amine group;

[0018] The monomer E is a styrene-based small monomer, represented by the general formula (Ⅲ):

[0019]

[0020] In formula (Ⅲ), R3 is H, -CH3, or -CH2CH3, and R4 is H, CH3, OCH3, CH2CH3, or SO3. - The monomer E is specifically selected from sodium styrene sulfonate, styrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, m-ethylstyrene, p-hydroxystyrene, α-methylstyrene, and α-ethylstyrene, and is mixed in any proportion.

[0021] The monomer F is a polymerizable phosphonic acid monomer, represented by general formula (Ⅳ):

[0022]

[0023] In formula (Ⅳ), R5 is H or CH3; n is the number of carbon atoms, which is an integer from 2 to 4; M2 is H, alkali metal ions, 1 / 2 alkaline earth metal ions, ammonium ions or organic amine groups.

[0024] The monomer F can be synthesized in a variety of ways according to existing technologies: (1) Phosphoric acid reacts with alcohol at high temperature and water is removed by a dehydrating agent to improve the reaction yield (US20080108732). (2) Phosphorylation of alcohol (CN1158132A, US20090258969).

[0025] The preparation method of monomer F of the present invention is as follows: unsaturated carboxylic acid ester and phosphorylation reagent are reacted at a temperature of 50-120°C, preferably 50-90°C;

[0026] The phosphorylating agent is selected from any one of phosphorus pentoxide, phosphoric acid, polyphosphoric acid, and pyrophosphoric acid.

[0027] The phosphorylation reaction time is 1 to 6 hours, preferably 2 to 4 hours;

[0028] The structure of the unsaturated carboxylic acid ester conforms to general formula (V):

[0029]

[0030] The unsaturated carboxylic acid ester is selected from any one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate.

[0031] The monomer F is selected from any one or more of hydroxyethyl methacrylate phosphate, hydroxyethyl acrylate phosphate, hydroxypropyl acrylate phosphate, and hydroxypropyl methacrylate phosphate, mixed in any proportion.

[0032] The present invention also provides a method for preparing the aforementioned highly adaptable polycarboxylate superplasticizer, the specific preparation steps of which are as follows:

[0033] (1) Amide / imide reaction: Compound A and compound B were heated to 60°C under nitrogen protection, and after adding a catalyst, the temperature was slowly increased to 80-130°C and held at the temperature for 2-6 hours. The temperature was then lowered to obtain amino polyether intermediate C with thiol groups at the end.

[0034] The catalyst is selected from any one or two of 4-dimethylaminopyridine, concentrated sulfuric acid, benzenesulfonic acid, p-toluenesulfonic acid, and ethylsulfonic acid in any proportion, and its amount is 0.05% to 10% of the mass of compound A.

[0035] (2) Copolymerization reaction: The amino polyether intermediate C with thiol end obtained in step (1) is subjected to free radical copolymerization reaction with monomers D, E and F in an aqueous medium under the action of an initiator to obtain the highly adaptable polycarboxylate superplasticizer.

[0036] The initiator is a conventional free radical water-soluble initiator, selected from any one or more of water-soluble azo initiators, ammonium persulfate, sodium persulfate, and potassium persulfate, and the amount used is 0.5% to 5.0% of the total weight of intermediate C, monomer D, monomer E, and monomer F.

[0037] When implementing step (2) of the present invention, intermediate C is added to the reaction vessel before the reaction begins, thereby improving its conversion rate; aqueous solutions of monomers D, E, and F, and aqueous solution of initiator are added to the reaction vessel dropwise after the reaction begins (in step 2, aqueous solutions of monomers D, E, F, and initiator are prepared first, and the concentration varies slightly depending on the polymerization concentration of the total monomers, as long as the total monomer concentration of the reaction is 20-60 wt%), the dropwise addition time is controlled at 2-6 h, the polymerization reaction time is controlled at 4-8 h; the polymerization concentration of the total monomers in the reaction is controlled at 20-60 wt%, and the polymerization temperature is controlled at 40-80 °C.

[0038] The high adaptability polycarboxylate superplasticizer described in this invention has a weight-average molecular weight of 5000-50000 Da; if the weight-average molecular weight of the high adaptability polycarboxylate superplasticizer is too small or too large, the water-reducing performance and slump retention performance will deteriorate.

[0039] The application method of the highly adaptable polycarboxylate superplasticizer of this invention is as follows: its dosage is 0.05% to 0.5% of the total weight of cementitious materials. As an improvement, the dosage of the highly adaptable polycarboxylate superplasticizer of this invention is 0.08 to 0.3 wt%. If the dosage is too low, the dispersion effect on cement will not be satisfactory; if the dosage is too high, it will result in economic waste, and the dispersion effect will not be further improved.

[0040] The application method of the highly adaptable polycarboxylate superplasticizer described in this invention is the same as that of existing superplasticizers, except for a slight difference in dosage. Those skilled in the art are generally aware that the specific dosage is related to the type of superplasticizer used.

[0041] The highly adaptable polycarboxylate superplasticizer described in this invention can also be used in combination with at least one type of known aminosulfonic acid superplasticizer, lignin-based general superplasticizer, and existing polycarboxylate superplasticizer. In addition to the known concrete superplasticizers mentioned above, air-entraining agents, expanding agents, retarders, accelerators, thickeners, shrinkage reducers, and defoamers can also be added.

[0042] The highly adaptable polycarboxylate superplasticizer product prepared by this invention has advantages such as low dosage, high water reduction rate, small slump loss, wide cement compatibility, and wide adaptability to the mud content of sand and gravel. The method of this invention has the advantages of readily available raw materials, simple production process with high yield, low production cost, and minimal environmental pollution.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] (1) The method of the present invention has the advantages of readily available raw materials, simple production process and high yield, low production cost and low environmental pollution.

[0045] (2) The highly adaptable polycarboxylate superplasticizer prepared by the method of the present invention has the advantages of low dosage, high water reduction rate, small slump loss, wide cement adaptability, and wide range of adaptability to mud content of sand and gravel. In particular, it has outstanding performance in overcoming the problems of adaptability of traditional comb-shaped cement superplasticizers and concrete raw materials, such as slow early dispersion, excessive loss, excessive superplasticizer dosage, and significant reverse growth. Detailed Implementation

[0046] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0047] To better understand the present invention, the following description, in conjunction with specific embodiments, further illustrates the invention.

[0048] In this embodiment of the invention, the weight-average molecular weight Mw of the polymer was determined using a miniDAWNTristar aqueous gel permeation chromatography (GPC) instrument manufactured by Wyatt Technology Corporation. The experimental conditions were as follows: column: TSK-GELSW (TOSOH), eluent: 0.1M NaNO3, flow rate: 0.8ml / min, injection: 20μl 0.1% aqueous solution (differential refractive index detector).

[0049] Comparative Example

[0050] 30.0 g of water was added to a four-necked flask equipped with a stirrer, thermometer, and dropping device. The temperature was raised to 90°C. Simultaneously, 100.0 g of polyethylene glycol monomethyl ether methacrylate (Mn = 1000 g / mol), a mixed monomer solution of 18.0 g of acrylic acid and 44.0 g of water, a mixed solution of 1.8 g of ammonium persulfate and 50.0 g of water, and a mixed solution of 1.21 g of sodium bisulfite and 50.0 g of water were added dropwise to the reactor over a period of 3 hours. After the addition was completed, the mixture was kept at this temperature for 2 hours. Then, 14.3 g of 35% NaOH solution was added for neutralization, yielding a traditional comb-shaped polycarboxylate superplasticizer mother liquor (Mw = 24.53 kDa). It is worth noting that this formulation is a laboratory formulation of a commercially available superplasticizer.

[0051] Example 1

[0052] (1) Amide / imide reaction: 120.0g of amino polyether (x+z=3.6, y=9, Mw=600) and 36.8g of mercaptoacetic acid were heated to 60℃ under nitrogen protection, 0.06g of ethyl sulfonic acid was added, and the temperature was slowly raised to 80℃ and held at a constant temperature for 6h. The temperature was then lowered to obtain amino polyether intermediate C with thiol groups at the end.

[0053] (2) Copolymerization reaction: 129.0g of deionized water was added to 193.8g of amino polyether intermediate C with thiol groups at the end obtained in step (1). The reaction vessel was purged with nitrogen while stirring, and the temperature was raised to 80℃ and stirred evenly. Then, 2.0g of styrene, 380.6g of hydroxyethyl acrylate phosphate, 28.8g of ammonium persulfate and 255.0g of water were mixed and stirred to prepare a uniform monomer aqueous solution. This solution was added dropwise to the reactor for 2 hours. After the addition was completed, the reaction was kept at the temperature for 2 hours and then cooled to room temperature to obtain a highly adaptable polycarboxylate superplasticizer with a solid content of 60.01% (Mw = 0.98kDa).

[0054] Example 2

[0055] (1) Amide / imide reaction: 120.0g of amino polyether (x+z=3.6, y=9, Mw=600) and 29.7g of 2-mercaptopropionic acid were heated to 60℃ under nitrogen protection, 1.2g of p-toluenesulfonic acid was added, and the temperature was slowly raised to 100℃ and held at a constant temperature for 4h. The temperature was then lowered to obtain amino polyether intermediate C with thiol groups at the end.

[0056] (2) Copolymerization reaction: 141.0g of deionized water was added to 211.8g of amino polyether intermediate C with thiol end obtained in step (1). The reaction vessel was purged with nitrogen while stirring and the temperature was raised to 60℃ and stirred evenly. Then, 36.9g of methacrylic acid (R1=CH3, R2=H in the general formula of monomer D), 7.6g of α-methylstyrene, 168.1g of hydroxyethyl acrylate phosphate, 8.5g of azobisisobutyramidine hydrochloride and 283.1g of water were mixed and stirred to prepare a uniform monomer aqueous solution. The solution was added dropwise to the reactor for 3h. After the addition was completed, the reaction was kept at the temperature for 2h and cooled to room temperature to obtain a highly adaptable polycarboxylate superplasticizer with a solid content of 49.9% (Mw=3.26kDa).

[0057] Example 3

[0058] (1) Amide / imide reaction: 135.0g of amino polyether (x+z=6, y=12.5, Mw=900) and 28.6g of 2-mercaptopropionic acid were heated to 60℃ under nitrogen protection, 2.7g of benzenesulfonic acid was added, and the temperature was slowly raised to 110℃ and held at a constant temperature for 3h. The temperature was then lowered to obtain amino polyether intermediate C with thiol groups at the end.

[0059] (2) Copolymerization reaction: 148.0g of deionized water was added to 221.3g of the amino polyether intermediate C with thiol groups at the end obtained in step (1). The reaction vessel was purged with nitrogen while stirring, and the temperature was raised to 60℃ and stirred until homogeneous. Then 40.6g of maleic acid (in the general formula of monomer D, R1=H, 9.2g of p-ethylstyrene, 73.5g of hydroxyethyl methacrylate phosphate, 10.3g of sodium persulfate and 369.5g of water were mixed and stirred to prepare a homogeneous monomer aqueous solution. This solution was added dropwise to the reactor over a period of 4 hours. After the addition was complete, the reaction was maintained at the temperature for 2 hours and then cooled to room temperature to obtain a highly adaptable polycarboxylate superplasticizer with a solid content of 40.1% (Mw = 1.79kDa).

[0060] Example 4

[0061] (1) Amide / imide reaction: 135.0g of amino polyether (x+z=6, y=12.5, Mw=900) and 21.8g of L-2-amino-3-mercaptopropionic acid were heated to 60℃ under nitrogen protection, 4.05g of concentrated sulfuric acid was added, and the temperature was slowly raised to 100℃ and kept at a constant temperature for 4h. The temperature was then lowered to obtain amino polyether intermediate C with thiol groups at the end.

[0062] (2) Copolymerization reaction: 102.0g of deionized water was added to 153.2g of the amino polyether intermediate C with thiol groups obtained in step (1), the reaction vessel was purged with nitrogen while stirring, and the temperature was raised to 40℃ and stirred evenly; then 48.7g of itaconic anhydride (in the general formula of monomer D, R1=H, It also forms an anhydride with COOM1), 20.2g sodium styrene sulfonate, 45.7g hydroxypropyl acrylate phosphate, 2.7g azobisisobutyramidine hydrochloride and 522.5g water phase are mixed and stirred to prepare a uniform monomer aqueous solution, which is added dropwise to the reactor over a period of 6 hours. After the addition is complete, the reaction is kept at the temperature for 2 hours and then cooled to room temperature to obtain a highly adaptable polycarboxylate superplasticizer with a solid content of 30.2% (Mw = 3.54kDa).

[0063] Example 5

[0064] (1) Amide / imide reaction: 200.0g of amino polyether (x+z=6,y=39,Mw=2000) and 17.0g of 3-mercaptopropionic acid were heated to 60℃ under nitrogen protection, and 10.0g of 4-dimethylaminopyridine was added. The temperature was then slowly raised to 120℃ and held for 3h. The mixture was then cooled to obtain amino polyether intermediate C with thiol groups at the end.

[0065] (2) Copolymerization reaction: 168.0 g of deionized water was added to 252.7 g of the amino polyether intermediate C with thiol groups at the end obtained in step (1). The reaction vessel was purged with nitrogen while stirring, and the temperature was raised to 50 °C and stirred until homogeneous. Then 50.4 g of 2-methylmaleic anhydride (in the general formula of monomer D, R1 = CH3, It also forms an anhydride with COOM1), 14.2 g of o-methylstyrene, 33.6 g of hydroxypropyl methacrylate phosphate, 14.0 g of potassium persulfate and 357.9 g of water are mixed and stirred to prepare a uniform monomer aqueous solution. This solution is added dropwise to the reactor over a period of 5 hours. After the addition is complete, the reaction is kept at a constant temperature for 2 hours and then cooled to room temperature to obtain a highly adaptable polycarboxylate superplasticizer with a solid content of 39.8% (Mw = 2.67 kDa).

[0066] Example 6

[0067] (1) Amide / imide reaction: 200.0g of amino polyether (x+z=6,y=39,Mw=2000) and 11.1g of 3-mercaptopropionic acid were heated to 60℃ under nitrogen protection, 20.0g of concentrated sulfuric acid was added, and the temperature was slowly raised to 130℃ and held at the temperature for 2h. The temperature was then lowered to obtain amino polyether intermediate C with thiol groups at the end.

[0068] (2) Copolymerization reaction: 112.0g of deionized water was added to 168.5g of amino polyether intermediate C with thiol end obtained in step (1). The reaction vessel was purged with nitrogen while stirring and the temperature was raised to 70℃ and stirred evenly. Then, 5.0g of sodium acrylate (R1=H, R2=H in the general formula of monomer D), 1.7g of p-hydroxystyrene, 2.4g of hydroxypropyl methacrylate phosphate, 0.9g of ammonium persulfate and 598.0g of water were mixed and stirred to prepare a uniform monomer aqueous solution. The solution was added dropwise to the reactor for 3h. After the addition was completed, the reaction was kept at the temperature for 2h and cooled to room temperature to obtain a highly adaptable polycarboxylate superplasticizer with a solid content of 20.1% (Mw=4.98kDa).

[0069] Application Examples

[0070] In the application examples, the cement used is Onoda PⅡ52.5, Conch P·O 42.5 produced by Anhui Conch Cement Co., Ltd., and Helin P·O 42.5 produced by Jiangsu Helin Cement Co., Ltd.

[0071] In the application examples, the test methods shall be carried out in accordance with the relevant provisions of GB8077-2012 "Test Method for Homogeneity of Concrete Admixtures".

[0072] Application Example 1

[0073] The effects of the highly adaptable polycarboxylate superplasticizer synthesized in the evaluation examples and the conventional comb-shaped superplasticizer synthesized in the comparative examples on the fluidity of fresh cement paste and its loss over time were investigated. The water-cement ratio was fixed at 0.29, and Onoda PⅡ52.5 cement was used. The experimental results are shown in Table 1.

[0074] Table 1. Effects of different water-reducing agents on the fluidity and time-dependent loss of freshly mixed cement paste.

[0075]

[0076]

[0077] The data in Table 1 show that, compared to the traditional comb-shaped water-reducing agent synthesized in the comparative example, at a water-cement ratio of 0.29 and a dosage of 0.10%, the initial flowability of the neat cement paste was 219 mm, and the flowability after 30 minutes was 175 mm. At a dosage of 0.12%, the initial flowability was 246 mm, and the flowability after 30 minutes was 209 mm. In the examples, the highly adaptable polycarboxylate water-reducing agent synthesized in the examples, at a dosage of 0.10% of the cement weight, exhibited better initial and 30-minute flowability of the freshly mixed paste than the comparative example. For example, in Example 2, the initial flowability was 274 mm, and the flowability after 30 minutes was 260 mm. Therefore, compared to the traditional comb-shaped water-reducing agent, the highly adaptable polycarboxylate water-reducing agent has the characteristics of low dosage, high water reduction rate, and excellent slump retention.

[0078] Application Example 2

[0079] The adaptability of the highly adaptable polycarboxylate superplasticizers obtained in Examples 1, 2 and 4 of this invention to the traditional comb-shaped superplasticizers obtained in the comparative examples in different cements was evaluated. The water-cement ratio was fixed at 0.29, and the results of the paste fluidity are shown in Table 3.

[0080] Table 2. Adaptability of Highly Adaptable Polycarboxylate Superplasticizer in Different Types of Cement

[0081]

[0082] The results in Table 2 show that, regardless of the type of cement, the cement with the high adaptability polycarboxylate superplasticizer prepared in the embodiments of the present invention has good initial fluidity and good dispersion retention performance, indicating that the high adaptability polycarboxylate superplasticizer has good adaptability in different types of cement.

[0083] Application Example 3

[0084] The adaptability of the highly adaptable polycarboxylate superplasticizers obtained in Examples 2, 3, and 5 of this invention to the mud content in cement was evaluated with the traditional comb-shaped superplasticizer obtained in the comparative example. The water-cement ratio was fixed at 0.29, and Onoda PⅡ52.5 was used. The results of the paste fluidity are shown in Table 3.

[0085] Table 3. Adaptability of highly adaptable polycarboxylate superplasticizers to the mud content in cement.

[0086]

[0087] The results in Table 3 show that when the water-cement ratio is fixed at 0.29, the amount of traditional comb-shaped water-reducing agent required for powders with high mud content increases significantly, requiring a 50% increase in dosage. However, for the highly adaptable polycarboxylate water-reducing agent, the increase in dosage is significantly reduced (the dosage needs to be increased by 30%). This indicates that the highly adaptable polycarboxylate water-reducing agent has a wide range of adaptability to mud content in sand and gravel, and has outstanding advantages in overcoming the adaptability of traditional comb-shaped cement dispersants and clay-containing materials.

Claims

1. A highly adaptable polycarboxylate superplasticizer, characterized in that: The highly adaptable polycarboxylate superplasticizer is obtained by intermediate C, which is obtained by amide / imide reaction of compound A and compound B, and intermediate C is then copolymerized with monomers D, E and F. The molar ratio of compound A to compound B is 1:1.05 to 1:2; The molar ratio of intermediate C to monomers D, E, and F satisfies: C / (D+E+F) = 1 / 1 to 1 / 7. Monomers D and F are mixed in any proportion. The molar ratio of monomer E to monomers D and F satisfies: E / (D+F) = 1 / 100 to 1 / 4. The compound A is an amino polyether, represented by the general formula (Ⅰ): （Ⅰ）； In the formula, x and z are the average molar additions of polyoxypropylene (PO), each independently chosen from 1 to 20, and (x+z)≤50; y is the average molar addition of polyoxyethylene (EO), which is from 1 to 50. Compound B is a carboxylic acid containing a thiol group; The monomer D is an unsaturated carboxylic acid, represented by the general formula (II): （Ⅱ） In formula (II), R1 is H or CH3, and R2 is H or m are integers satisfying 0 ≤ m ≤ 3; when R2 is When it reacts with COOM1 in general formula (II) to form an anhydride; M1 is H, alkali metal ion, 1 / 2 alkaline earth metal ion, ammonium ion or organic amine group; The monomer E is a small monomer of styrene, represented by the general formula (Ⅲ): （Ⅲ） In formula (Ⅲ), R3 is H, -CH3, or -CH2CH3, and R4 is H, CH3, OCH3, CH2CH3, or SO3. - ; The monomer F is a polymerizable phosphonic acid monomer, represented by the general formula (Ⅳ): （Ⅳ） In formula (Ⅳ), R5 is H or CH3; n is the number of carbon atoms, which is an integer from 2 to 4; M2 is H, alkali metal ions, 1 / 2 alkaline earth metal ions, ammonium ions or organic amine groups.

2. The highly adaptable polycarboxylate superplasticizer according to claim 1, characterized in that, The compound B is selected from any one or more of mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and L-2-amino-3-mercaptopropionic acid.

3. The highly adaptable polycarboxylate superplasticizer according to claim 1, characterized in that, The monomer E is specifically selected from sodium styrene sulfonate, styrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, m-ethylstyrene, p-hydroxystyrene, α-methylstyrene, and α-ethylstyrene, mixed in any proportion.

4. The highly adaptable polycarboxylate superplasticizer according to claim 1, characterized in that, The monomer F is prepared by reacting an unsaturated carboxylic acid ester and a phosphorylation reagent at a temperature of 50-120°C; the phosphorylation reaction time is 1-6 h. The phosphorylating agent is selected from any one of phosphorus pentoxide, phosphoric acid, polyphosphoric acid, and pyrophosphoric acid. The structure of the unsaturated carboxylic acid ester conforms to general formula (V): （Ⅴ）。 5. A highly adaptable polycarboxylate superplasticizer according to claim 4, characterized in that, In the preparation method of monomer F, the reaction temperature is 50~90℃ and the phosphorylation reaction time is 2~4 h.

6. A highly adaptable polycarboxylate superplasticizer according to claim 4 or 5, characterized in that, The unsaturated carboxylic acid ester is selected from any one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate; The monomer F is selected from any one or more of hydroxyethyl methacrylate phosphate, hydroxyethyl acrylate phosphate, hydroxypropyl acrylate phosphate, and hydroxypropyl methacrylate phosphate, mixed in any proportion.

7. A method for preparing a highly adaptable polycarboxylate superplasticizer according to any one of claims 1 to 6, characterized in that, The specific preparation steps are as follows: (1) Amide / imide reaction: Compound A and compound B were heated to 60°C under nitrogen protection, and after adding a catalyst, the temperature was slowly increased to 80-130°C and held at the temperature for 2-6 hours. The temperature was then lowered to obtain amino polyether intermediate C with thiol groups at the end. The catalyst is selected from any one or two of 4-dimethylaminopyridine, concentrated sulfuric acid, benzenesulfonic acid, p-toluenesulfonic acid, and ethylsulfonic acid in any proportion, and its amount is 0.05% to 10% of the mass of compound A; (2) Copolymerization reaction: The amino polyether intermediate C with thiol groups at the end obtained in step (1) undergoes free radical copolymerization reaction with monomers D, E, and F in an aqueous medium under the action of an initiator to obtain the highly adaptable polycarboxylate superplasticizer; The initiator is a conventional free radical water-soluble initiator, selected from any one or more of water-soluble azo initiators, ammonium persulfate, sodium persulfate, and potassium persulfate, and is used in an amount of 0.5% to 5.0% of the total weight of intermediate C, monomer D, monomer E, and monomer F. The highly adaptable polycarboxylate superplasticizer has a weight-average molecular weight of 5000~50000 Da.

8. A method for preparing a highly adaptable polycarboxylate superplasticizer according to claim 7, characterized in that, In step (2), intermediate C is added to the reaction vessel before the reaction begins. The aqueous solutions of monomers D, E, and F, and the aqueous solution of the initiator are added to the reaction vessel dropwise after the reaction begins. The dropwise addition time is controlled at 2 to 6 hours, and the polymerization reaction time is controlled at 4 to 8 hours. In step (2), the total monomer concentration of the reaction is controlled to be 20-60 wt%, and the polymerization temperature is 40-80℃.

9. The application method of the highly adaptable polycarboxylate superplasticizer according to any one of claims 1 to 6, characterized in that, The dosage of the highly adaptable polycarboxylate superplasticizer is 0.05% to 0.5% of the total weight of the cementitious materials.

10. The application method of a highly adaptable polycarboxylate superplasticizer according to claim 9, characterized in that, The dosage of the highly adaptable polycarboxylate superplasticizer is 0.08~0.3wt% of the total cementitious material weight.

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