Polycarboxylic acid water reducing agent with dynamic self-regulating ability and preparation method thereof

Abstract

This invention discloses a polycarboxylate superplasticizer with dynamic self-regulating ability and its preparation method. The specific method includes: (1) preparing carboxyl-substituted crown ethers, ester-substituted crown ethers, and polyether-substituted crown ethers through substitution reactions. (2) preparing a rotaxane backbone through polymerization reactions. (3) assembling the backbone and substituted crown ethers into a rotaxane structure in solution and completing the end-capping using end-capping groups. The superplasticizer prepared by this invention has a rotaxane structure, which can effectively reduce chain coiling and folding, resulting in high water reduction rate, good dispersion and dispersion retention performance; it also has anti-cracking and shrinkage reduction effects; the carboxyl groups in the superplasticizer molecule and the ether chain structure on the side chain have dynamic adjustment capabilities, and by reducing intercalation reactions, it has excellent anti-mud effects in gelation systems. The product preparation process is mild, non-toxic, and pollution-free, and can be stored stably for a long time.

Description

Technical Field

[0001] This invention relates to the field of polycarboxylate superplasticizer technology, specifically to a polycarboxylate superplasticizer with dynamic self-regulating ability and its preparation method. Background Technology

[0002] With the ever-increasing demands for concrete quality in today's construction industry, water-reducing agents, as the largest admixture used in concrete, are becoming an increasingly important focus. Polycarboxylate superplasticizers, as a new type of admixture, have become one of the most commonly used admixtures in current concrete engineering due to their high water reduction rate and improved concrete workability and durability. There are various methods for preparing polycarboxylate superplasticizers, the most common being the free radical copolymerization of small and large monomers in an aqueous solution initiated by an initiator. This reaction process requires a large external heat source to continuously heat the reactor, resulting in high energy costs. Furthermore, it is worth noting that the free radical polymerization reaction used in the preparation of polycarboxylate superplasticizers is an exothermic reaction, with high temperatures that are difficult to control precisely, potentially leading to fluctuations in product performance and thus affecting the water-reducing properties of the superplasticizer.

[0003] Many scholars have studied this issue from the perspective of the structure of the water-reducing agent itself. Patent CN 116178617A, published on May 30, 2023, entitled "A Star-Shaped High-Performance Polycarboxylate Water-Reducing Agent and Its Preparation Method," was prepared by changing the amount of chain transfer agent and introducing maleic anhydride into the star-shaped initiator arm, avoiding the problems of intramolecular crosslinking and uncontrollable polymerization process present in traditional free radical polymerization. Patent CN116178613A, also published on May 30, 2023, entitled "A Comb-Type Topological Structure Polycarboxylate Water-Reducing Agent," introduced a comb-type topological structure into the main chain, which improved fluidity and pumpability at low dosages, while reducing the water-cement ratio and cement usage. Based on the above research, this application starts from the structure of the polycarboxylate water-reducing agent itself, utilizing the special properties of supramolecular polymers to further improve the crack resistance, shrinkage reduction, and mud resistance properties of the polycarboxylate water-reducing agent. Summary of the Invention

[0004] 1. The technical problem to be solved:

[0005] To address the aforementioned technical problems, this invention provides a polycarboxylate superplasticizer with dynamic self-regulation capabilities and its preparation method. Utilizing the special properties of supramolecular polymers, it not only further solves the problems of low water reduction rate and slow dispersion speed of polycarboxylate superplasticizers in the prior art, but also further solves the problems of poor shrinkage resistance and poor clay tolerance of polycarboxylate superplasticizers in the prior art.

[0006] 2. Technical Solution:

[0007] A polycarboxylate superplasticizer with dynamic self-regulating capability is characterized by having the following structure:

[0008]

[0009] In the above formula, the degree of polymerization m is 1 to 100; the degree of polymerization n is 0 to 100; the degree of polymerization p is 20 to 100; r, t, and s are each independently 0 to 2; x and y are each independently 1 to 4; P is an O, N, or NH atom; R1 is one of H, alkali metal ions, alkyl groups containing 1 to 6 carbon atoms, hydroxyalkyl groups containing 1 to 6 carbon atoms, or alkoxy groups containing 1 to 6 carbon atoms; R2, R3, R4, and R5 are any one or more combinations of alkyl groups containing 1 to 4 carbon atoms, hydroxyalkyl groups containing 1 to 4 carbon atoms, or alkoxy groups containing 1 to 4 carbon atoms.

[0010] A method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability, characterized by comprising the following steps:

[0011] Step 1: Preparation of monohydroxy-substituted crown ethers, carboxyl-substituted crown ethers, ester-substituted crown ethers, and polyether-substituted crown ethers:

[0012] The glycol compound was stirred with an alkaline solution in a reaction flask, and p-toluenesulfonyl chloride was added dropwise at 0–10 °C. The reaction was stirred at room temperature for 5–15 h to obtain a terminal-substituted glycol. The triol compound was added dropwise to the first solvent containing the terminal-substituted glycol, and the first catalyst was added and stirred under reflux for 10–30 h to obtain a monohydroxy-substituted crown ether.

[0013] A monohydroxy-substituted crown ether is added to a first solvent, and a first oxidizing agent is added and refluxed for 10–25 h to obtain a carboxyl-substituted crown ether;

[0014] Carbonyl unsaturated acids and their derivatives are added to monohydroxy substituted crown ethers, and the reaction is carried out for 2-8 hours to obtain ester-substituted crown ethers.

[0015] The monohydroxy-substituted crown ether is stirred and refluxed with a halogenating agent in a reaction flask to obtain a halogen-substituted crown ether. The halogen-substituted crown ether and the polyether macromonomer or ester macromonomer are dissolved in the first solvent, and an acid-binding agent is added dropwise to obtain a polyether-substituted crown ether.

[0016] Step 2: Preparation of functionalized polyamides:

[0017] Polyamide is obtained by stirring polyacid and polyamine in a reaction flask and reacting under high temperature and vacuum for 1-5 hours. Polyamide is then dissolved in a second solvent, an inorganic salt is added, and a precipitate is formed. After filtration, the solid obtained is functionalized polyamide.

[0018] Step 3: Preparation of rotaxane-type polycarboxylate superplasticizer: Functionalized polyamide, carboxyl-substituted crown ether, and polyether-substituted crown ether are dissolved in a third solvent, stirred, and then evaporated to dryness to obtain a solid; the solid is reacted with a capping agent under alkaline conditions for 2-8 hours to obtain a polycarboxylate superplasticizer with dynamic self-regulating ability.

[0019] Furthermore, the glycol compound is any one or a combination of pentaethylene glycol, hexaethylene glycol, and heptaethylene glycol; the alkaline solution is any one or a combination of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, silver hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, disodium bicarbonate, dipotassium bicarbonate, diethylamine, triethylamine, pyridine, and quaternary ammonium bases.

[0020] Further, the triol compound in step one is any one or a combination of 1,2,3-propanetriol, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,3-pentanetriol, 1,2,4-pentanetriol, 1,2,5-pentanetriol, and 1,3,5-pentanetriol.

[0021] Further, the first solvent is any one or a combination of acetonitrile, methanol, ethanol, tert-butanol, acetone, dichloromethane (DCM), chloroform, benzene, toluene, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and 1,2-dichloroethane; the first catalyst is any one or a combination of potassium carbonate, calcium carbonate, and barium carbonate; and the first oxidant is any one or a combination of potassium permanganate, pyridinium dichromate, chromium trioxide, potassium dichromate, and ruthenium tetroxide.

[0022] Further, the carbonyl unsaturated acid and its derivatives are any one or more combinations of acrylic acid, sodium acrylate, methacrylic acid, sodium methacrylate, maleic acid, sodium maleate, acrylamide, methacrylamide, N-ethylacrylamide, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxy-n-butyl methacrylate, 2-vinylbenzoic acid, 2-vinylphenylacetic acid, and methyl 2-vinylbenzoate.

[0023] Further, the halogenating agent is any one or a combination of hydrogen fluoride, hydrogen bromide, hydrogen iodide, phosphorus tribromide, phosphorus trichloride, thionyl chloride, hypobromic acid, hypochlorous acid, ferric chloride, and ferric tribromide; the polyether macromonomer or ester macromonomer is any one or a combination of polyethylene glycol, methyl allyl polyoxyethylene ether, isopentenyl polyoxyethylene ether, polyethylene glycol methacrylate, polyethylene glycol methacrylate, and methoxy polyethylene glycol acrylate.

[0024] Further, the acid-binding agent is any one or a combination of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, silver hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, disodium bicarbonate, dipotassium bicarbonate, diethylamine, triethylamine, pyridine, 4-dimethylaminopyridine (DMAP), N,N'-dicyclohexylcarboimide (DCC), N,N-diisopropylethylamine, and quaternary ammonium bases.

[0025] Further, the polyacid is any one or a combination of malonic acid, succinic acid, and glutaric acid; the polyamine is any one or a combination of two or more of ethylenediamine, propylenediamine, and butylenediamine; the second solvent is a composite solvent formed by mixing a fourth solvent (a combination of water, methanol, ethanol, n-butanol, isobutanol, tert-butanol, propylene glycol methyl ether, or propylene glycol ethyl ether) with water and a co-solvent; wherein the co-solvent is any one or a combination of two or more of DMF, acetonitrile, ethanesulfonyl acetonitrile, or acetamide; the volume ratio of water, the fourth solvent, and the co-solvent in the second solvent is 1:(3-6):(0.1-0.5); the inorganic salt is any one or a combination of potassium hexafluorophosphate, potassium chloride, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0026] Further, the third solvent is a composite solvent formed by mixing a fourth solvent, which is any one or more of water, methanol, ethanol, n-butanol, isobutanol, tert-butanol, propylene glycol methyl ether or propylene glycol ethyl ether, with water and a co-solvent; wherein the co-solvent is any one or more of DMF, acetonitrile, ethanesulfonyl acetonitrile or acetamide; and the end-capping agent is any one or more of bromoanthracene, iodoanthracene, and chloroanthracene.

[0027] 3. Beneficial effects:

[0028] (1) The carboxyl group and ether chain structure on the side chain of the water-reducing agent molecule prepared by the present invention have dynamic adjustment capabilities, which can effectively reduce intercalation reaction and have excellent anti-mud effect in the gelation system.

[0029] (2) In this invention, after preparing carboxyl-substituted crown ether, ester-substituted crown ether and polyethylene glycol-substituted crown ether by substitution reaction, rotaxane backbone is prepared by polymerization reaction. Therefore, the prepared water-reducing agent has rotaxane structure, which can effectively reduce chain coiling and folding, has strong steric hindrance effect in gelation system, improves water reduction rate, and has excellent dispersion and dispersion retention performance.

[0030] (3) The water-reducing agent prepared by the present invention has rigid groups such as anthracene in its structure, which can reduce the surface tension of water in concrete, thereby reducing the shrinkage problem caused by water evaporation and achieving the effect of crack resistance and shrinkage reduction.

[0031] (4) The preparation method of the polycarboxylate superplasticizer disclosed in this invention has mild preparation conditions, low energy consumption, and can reduce production costs and stabilize production. Detailed Implementation

[0032] The present invention will be described in detail below through embodiments.

[0033] Example 1

[0034] 1 mol of pentaethylene glycol and 2.2 mol of sodium hydroxide were stirred in a reaction flask, and 2.1 mol of p-toluenesulfonyl chloride was added dropwise at 0 °C. The mixture was stirred at room temperature for 12 h to obtain pentaethylene glycol with two substituted ends. 1,2,4-Butanetriol (1.1 mol) was added dropwise to a mixed solution of anhydrous acetonitrile (150 ml) containing the above pentaethylene glycol substitute (1 mol) and potassium carbonate (1.2 mol). The mixture was stirred and refluxed for 24 h to obtain a monohydroxy substituted crown ether. Pyridinium dichromate (0.2 mol) was added to anhydrous D-type acetonitrile solution containing the monohydroxy substituted crown ether (1 mol). Carboxyl-substituted crown ethers were obtained by refluxing in MF (150 ml) solution for 24 h; sodium hydroxide (0.2 mol) was added to an acetic acid solution of monohydroxy-substituted crown ether (1 mol) and reacted for 5 h to obtain ester-substituted crown ethers; 1 mol of monohydroxy-substituted crown ethers and 1.1 mol of phosphorus tribromide were stirred and refluxed in a reaction flask to obtain brominated crown ethers; polyethylene glycol (1.1 mol) was added dropwise to an aqueous solution of acetonitrile (150 ml) containing the above brominated crown ether (1 mol), and sodium hydroxide (1.2 mol) was added and stirred and refluxed to obtain polyethylene glycol-substituted crown ethers;

[0035] 1 mol of malonic acid and 1.1 mol of ethylenediamine were stirred in a reaction flask and reacted at 100°C under vacuum for 3 hours to obtain polyethylenediamine malonate. 1 mol of polyethylenediamine malonate was dissolved in 50 ml of a mixed solvent of water and DMF (water / DMF = 4:1, v / v), and 2.2 mol of ammonium hexafluorophosphate was added. After precipitation, the solid was obtained by filtration.

[0036] 1 mol of the above solid was dissolved in 50 ml of water along with 1 mol of carboxyl-substituted crown ether and 1 mol of polyethylene glycol-substituted crown ether. The mixture was stirred for 6 h and then evaporated to dryness to obtain the solid. The above solid was then reacted with 2 mol of bromoanthracene under alkaline conditions for 4 h to obtain the final product.

[0037] The molecular structure is as follows:

[0038]

[0039] In the above formula, the degree of polymerization m is 40; the degree of polymerization p is 28.

[0040] Example 2

[0041] 1 mol of pentaethylene glycol and 2.2 mol of sodium hydroxide were stirred in a reaction flask, and 2.1 mol of p-toluenesulfonyl chloride was added dropwise at 0 °C. The mixture was stirred at room temperature for 12 h to obtain pentaethylene glycol with two substituted ends. 1,2,4-Butanetriol (1.1 mol) was added dropwise to a mixed solution of anhydrous acetonitrile (150 ml) containing the above pentaethylene glycol substitute (1 mol) and potassium carbonate (1.2 mol). The mixture was stirred and refluxed for 24 h to obtain a monohydroxy substituted crown ether. Pyridinium dichromate (0.2 mol) was added to anhydrous D-type acetonitrile solution containing the monohydroxy substituted crown ether (1 mol). Carboxyl-substituted crown ethers were obtained by refluxing in MF (150 ml) solution for 24 h; sodium hydroxide (0.2 mol) was added to an acetic acid solution of monohydroxy-substituted crown ether (1 mol) and reacted for 5 h to obtain ester-substituted crown ethers; 1 mol of monohydroxy-substituted crown ethers and 1.1 mol of phosphorus tribromide were stirred and refluxed in a reaction flask to obtain brominated crown ethers; polyethylene glycol (1.1 mol) was added dropwise to an aqueous solution of acetonitrile (150 ml) containing the above brominated crown ether (1 mol), and sodium hydroxide (1.2 mol) was added and stirred and refluxed to obtain polyethylene glycol-substituted crown ethers;

[0042] 1 mol of malonic acid and 1.1 mol of ethylenediamine were stirred in a reaction flask and reacted at 105°C under vacuum for 3 hours to obtain polyethylenediamine malonate. 1 mol of polyethylenediamine malonate was dissolved in 50 ml of a mixed solvent of water and DMF (water / DMF = 4:1, v / v), and 2.2 mol of ammonium hexafluorophosphate was added. After precipitation, the solid was obtained by filtration.

[0043] 2 mol of the above solid was dissolved in 50 ml of water along with 2 mol of carboxyl-substituted crown ether, 1 mol of polyethylene glycol-substituted crown ether, and 1 mol of ester-substituted crown ether. The mixture was stirred for 6 h and then evaporated to dryness to obtain the solid. The above solid was then reacted with 2 mol of bromoanthracene under alkaline conditions for 4 h to obtain the final product.

[0044] The molecular structure is as follows:

[0045]

[0046] In the above formula, the degree of polymerization m is 20; the degree of polymerization n is 20; and the degree of polymerization p is 28.

[0047] Example 3

[0048] 1 mol of hexaethylene glycol and 2.2 mol of sodium hydroxide were stirred in a reaction flask, and 2.1 mol of p-toluenesulfonyl chloride was added dropwise at 0 °C. The reaction was stirred at room temperature for 12 h to obtain hexaethylene glycol with two substituted ends. 1,2,4-Butanetriol (1.1 mol) was added dropwise to a mixed solution of anhydrous acetonitrile (150 ml) containing the above-mentioned hexaethylene glycol substitute (1 mol) and potassium carbonate (1.2 mol), and the mixture was stirred and refluxed for 24 h to obtain a monohydroxy substituted crown ether. 0.2 mol of pyridinium dichromate was added to anhydrous DMF containing the monohydroxy substituted crown ether (1 mol). In a 150 ml solution, reflux for 24 h to obtain carboxyl-substituted crown ethers; add sodium hydroxide (0.2 mol) to a 1 mol monohydroxy-substituted crown ether in an acetic acid (1 mol) solution and react for 5 h to obtain ester-substituted crown ethers; stir and reflux 1 mol monohydroxy-substituted crown ether with 1.1 mol phosphorus tribromide in a reaction flask to obtain brominated crown ethers; add polyethylene glycol (1.1 mol) dropwise to an acetonitrile (150 ml) aqueous solution containing the above brominated crown ether (1 mol), add sodium hydroxide (1.2 mol), and stir and reflux to obtain polyethylene glycol-substituted crown ethers;

[0049] 1 mol of malonic acid and 1.1 mol of ethylenediamine were stirred in a reaction flask and reacted at 110°C under vacuum for 3 hours to obtain polyethylenediamine malonate. 1 mol of polyethylenediamine malonate was dissolved in 50 ml of a mixed solvent of water and DMF (water / DMF = 4:1, v / v), and 2.2 mol of ammonium hexafluorophosphate was added. After precipitation, the solid was obtained by filtration.

[0050] 1 mol of the above solid was dissolved in 50 ml of water along with 1 mol of carboxyl-substituted crown ether and 1 mol of polyethylene glycol-substituted crown ether. The mixture was stirred for 6 h and then evaporated to dryness to obtain the solid. The above solid was then reacted with 2 mol of bromoanthracene under alkaline conditions for 4 h to obtain the final product.

[0051] The molecular structure is as follows:

[0052]

[0053] In the above formula, the degree of polymerization m is 40; the degree of polymerization p is 28.

[0054] Example 4

[0055] 1 mol of hexaethylene glycol and 2.2 mol of sodium hydroxide were stirred in a reaction flask, and 2.1 mol of p-toluenesulfonyl chloride was added dropwise at 0 °C. The reaction was stirred at room temperature for 12 h to obtain hexaethylene glycol with two substituted ends. 1,2,4-Butanetriol (1.1 mol) was added dropwise to a mixed solution of anhydrous acetonitrile (150 ml) containing the above-mentioned hexaethylene glycol substitute (1 mol) and potassium carbonate (1.2 mol), and the mixture was stirred and refluxed for 24 h to obtain a monohydroxy substituted crown ether. 0.2 mol of pyridinium dichromate was added to anhydrous DMF containing the monohydroxy substituted crown ether (1 mol). In a 150 ml solution, reflux for 24 h to obtain carboxyl-substituted crown ethers; add sodium hydroxide (0.2 mol) to a 1 mol monohydroxy-substituted crown ether in an acetic acid (1 mol) solution and react for 5 h to obtain ester-substituted crown ethers; stir and reflux 1 mol monohydroxy-substituted crown ether with 1.1 mol phosphorus tribromide in a reaction flask to obtain brominated crown ethers; add polyethylene glycol (1.1 mol) dropwise to an acetonitrile (150 ml) aqueous solution containing the above brominated crown ether (1 mol), add sodium hydroxide (1.2 mol), and stir and reflux to obtain polyethylene glycol-substituted crown ethers;

[0056] 1 mol of malonic acid and 1.1 mol of ethylenediamine were stirred in a reaction flask and reacted at 105°C under vacuum for 3 hours to obtain polyethylenediamine malonate. 1 mol of polyethylenediamine malonate was dissolved in 50 ml of a mixed solvent of water and DMF (water / DMF = 4:1, v / v), and 2.2 mol of ammonium hexafluorophosphate was added. After precipitation, the solid was obtained by filtration.

[0057] 2 mol of the above solid was dissolved in 50 ml of water along with 2 mol of carboxyl-substituted crown ether, 1 mol of polyethylene glycol-substituted crown ether, and 1 mol of ester-substituted crown ether. The mixture was stirred for 6 h and then evaporated to dryness to obtain the solid. The above solid was then reacted with 2 mol of bromoanthracene under alkaline conditions for 4 h to obtain the final product.

[0058] The molecular structure is as follows:

[0059]

[0060] In the above formula, the degree of polymerization m is 20; the degree of polymerization n is 20; and the degree of polymerization p is 28.

[0061] Example 5

[0062] 1 mol of pentaethylene glycol and 2.2 mol of sodium hydroxide were stirred in a reaction flask, and 2.1 mol of p-toluenesulfonyl chloride was added dropwise at 0 °C. The reaction was stirred at room temperature for 12 h to obtain pentaethylene glycol with two substituted ends. 1,2,4-Butanetriol (1.1 mol) was added dropwise to a mixed solution of anhydrous acetonitrile (150 ml) containing the above pentaethylene glycol substitute (1 mol) and potassium carbonate (1.2 mol), and the mixture was stirred under reflux for 24 h to obtain a monohydroxy substituted crown ether. 0.2 mol of pyridinium dichromate was added to anhydrous DMF containing the monohydroxy substituted crown ether (1 mol). In a 150 ml solution, reflux for 24 h to obtain carboxyl-substituted crown ethers; add sodium hydroxide (0.2 mol) to a 1 mol monohydroxy-substituted crown ether in an acetic acid (1 mol) solution and react for 5 h to obtain ester-substituted crown ethers; stir and reflux 1 mol monohydroxy-substituted crown ether with 1.1 mol phosphorus tribromide in a reaction flask to obtain brominated crown ethers; add polyethylene glycol (1.1 mol) dropwise to an acetonitrile (150 ml) aqueous solution containing the above brominated crown ether (1 mol), add sodium hydroxide (1.2 mol), and stir and reflux to obtain polyethylene glycol-substituted crown ethers;

[0063] 1 mol of succinic acid and 1.1 mol of propylenediamine were stirred in a reaction flask and reacted at 100°C under vacuum for 3 hours to obtain polypropylenediamine succinate. 1 mol of polypropylenediamine succinate was dissolved in 50 ml of a mixed solvent of water and DMF (water / DMF = 4:1, v / v), and 2.2 mol of ammonium hexafluorophosphate was added. After precipitation, the solid was obtained by filtration.

[0064] 1 mol of the above solid was dissolved in 50 ml of water along with 1 mol of carboxyl-substituted crown ether and 1 mol of polyethylene glycol-substituted crown ether. The mixture was stirred for 6 h and then evaporated to dryness to obtain the solid. The above solid was then reacted with 2 mol of bromoanthracene under alkaline conditions for 4 h to obtain the final product.

[0065] The molecular structure is as follows:

[0066]

[0067] In the above formula, the degree of polymerization m is 40; the degree of polymerization p is 28.

[0068] Example 6

[0069] 1 mol of hexaethylene glycol and 2.2 mol of sodium hydroxide were stirred in a reaction flask, and 2.1 mol of p-toluenesulfonyl chloride was added dropwise at 0 °C. The mixture was stirred at room temperature for 12 h to obtain hexaethylene glycol with two substituted ends. 1,2,4-Butanetriol (1.1 mol) was added dropwise to a mixed solution of anhydrous acetonitrile (150 ml) containing the above-mentioned hexaethylene glycol substitute (1 mol) and potassium carbonate (1.2 mol), and the mixture was stirred and refluxed for 24 h to obtain a monohydroxy substituted crown ether. Pyridinium dichromate (0.2 mol) was added to anhydrous D-type acetonitrile solution containing the monohydroxy substituted crown ether (1 mol). Carboxyl-substituted crown ethers were obtained by refluxing in MF (150 ml) solution for 24 h; sodium hydroxide (0.2 mol) was added to an acetic acid solution of monohydroxy-substituted crown ether (1 mol) and reacted for 5 h to obtain ester-substituted crown ethers; 1 mol of monohydroxy-substituted crown ethers and 1.1 mol of phosphorus tribromide were stirred and refluxed in a reaction flask to obtain brominated crown ethers; polyethylene glycol (1.1 mol) was added dropwise to an aqueous solution of acetonitrile (150 ml) containing the above brominated crown ether (1 mol), and sodium hydroxide (1.2 mol) was added and stirred and refluxed to obtain polyethylene glycol-substituted crown ethers;

[0070] 1 mol of succinic acid and 1.1 mol of propylenediamine were stirred in a reaction flask and reacted at 110°C under vacuum for 3 hours to obtain polypropylenediamine succinate. 1 mol of polypropylenediamine succinate was dissolved in 50 ml of a mixed solvent of water and DMF (water / DMF = 4:1, v / v), and 2.2 mol of ammonium hexafluorophosphate was added. After precipitation, the solid was obtained by filtration.

[0071] 2 mol of the above solid was dissolved in 50 ml of water along with 2 mol of carboxyl-substituted crown ether, 1 mol of polyethylene glycol-substituted crown ether, and 1 mol of ester-substituted crown ether. The mixture was stirred for 6 h and then evaporated to dryness to obtain the solid. The above solid was then reacted with 2 mol of bromoanthracene under alkaline conditions for 4 h to obtain the final product.

[0072] The molecular structure is as follows:

[0073]

[0074] In the above formula, the degree of polymerization m is 20; the degree of polymerization n is 20; and the degree of polymerization p is 28.

[0075] Comparative Example 1

[0076] Acrylic acid (4 mol) and allyl polyoxyethylene ether (1 mol, Mw = 1000 g / mol) were subjected to free radical polymerization at 35 °C for 5 h under the combined action of ammonium persulfate (0.07 mol), ascorbic acid (0.04 mol) and 3-mercaptopropionic acid (0.04 mol) to obtain polycarboxylate superplasticizer (Mw = 35000 g / mol).

[0077] The molecular structure is as follows:

[0078]

[0079] The degrees of polymerization m, n, and p are 22, 5, and 22, respectively.

[0080] Comparative Example 2

[0081] Acrylic acid (5 mol) and methyl allyl polyoxyethylene ether (1 mol, Mw = 1500 g / mol) were subjected to free radical polymerization at 30 °C for 5 h under the combined action of hydrogen peroxide (0.1 mol), sodium bisulfite (0.1 mol) and 2-mercaptopropionic acid (0.1 mol) to obtain a polycarboxylate superplasticizer (Mw = 40000 g / mol).

[0082] The molecular structure is as follows:

[0083]

[0084] In the above formula, the degree of polymerization m, n and p are 17, 3 and 33, respectively.

[0085] Test case

[0086] 1. Cement paste fluidity test

[0087] Referring to GB / T 8077-2012 "Test Method for Homogeneity of Concrete Admixtures", the flowability of the neat paste was tested on the samples obtained in Examples 1 to 6, Comparative Example 1, and Comparative Example 2. The results are shown in Table 1. The W / C ratio was 0.29, and the admixture dosage (converted to solids) was 0.14% of the cement content. The initial flowability of the neat paste (after mixing), the flowability of the neat paste after 1 hour, and the flowability of the neat paste after 2 hours were tested. Compared with the ordinary polycarboxylate superplasticizer in the comparative example, the neat pastes of all examples showed a significant improvement in initial dispersion and dispersion retention.

[0088] Table 1. Flowability and loss over time of different samples of paste

[0089]

[0090] 2. Concrete performance testing

[0091] Referring to GB 8076-2008 "Concrete Admixtures", the initial slump / spread, slump / spread loss over 1 hour, and concrete specimen strength of the samples obtained in Examples 1 to 6, Comparative Example 1, and Comparative Example 2 were measured. During the tests, 2% montmorillonite was used to replace cement, and the admixture dosage was 1.6% of the cement weight. The results are shown in Table 2. In the presence of montmorillonite, compared to the ordinary polycarboxylate superplasticizer in the comparative example, the concrete slump / spread of the examples showed a significant improvement at different times, and the compressive strength also showed a certain improvement at different times. Specifically, the 3-day compressive strength increased by an average of 14.1%, the 7-day compressive strength increased by 10.8%, and the 28-day compressive strength increased by 7.8%. Furthermore, all examples also showed better shrinkage resistance compared to the comparative example.

[0092] Table 2. Slump retention and mechanical properties of concrete samples from different samples

[0093]

[0094] Although the present invention has been disclosed above with reference to preferred embodiments, these are not intended to limit the invention. Any person skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be defined by the scope of the claims of this application.

Claims

1. A polycarboxylate superplasticizer with dynamic self-regulating capability, characterized in that: It has the following structure: ； In the above formula, the degree of polymerization m is 1~100; the degree of polymerization n is 0~100; the degree of polymerization p is 20~100; r, t, and s are each independently 0~2 and r, t, and s cannot be 0 at the same time; x and y are each independently 1~4; P is an O, N, or NH atom; R1 is one of H, alkali metal ions, alkyl groups containing 1~6 carbon atoms, hydroxyalkyl groups containing 1~6 carbon atoms, or alkoxy groups containing 1~6 carbon atoms; R2, R 3、 R4 and R5 are any one or more combinations of alkyl groups containing 1 to 4 carbon atoms and hydroxyalkyl groups containing 1 to 4 carbon atoms.

2. A method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability, used to prepare the polycarboxylate superplasticizer as described in claim 1, characterized in that: Includes the following steps: Step 1: Preparation of monohydroxy-substituted crown ethers, carboxyl-substituted crown ethers, ester-substituted crown ethers, and polyether-substituted crown ethers: The glycol compound was stirred with an alkaline solution in a reaction flask, and p-toluenesulfonyl chloride was added dropwise at 0-10°C. The reaction was stirred at room temperature for 5-15 hours to obtain a terminal-substituted glycol. The triol compound was added dropwise to the first solvent containing the terminal-substituted glycol, and the first catalyst was added and stirred under reflux for 10-30 hours to obtain a monohydroxy-substituted crown ether. A monohydroxy-substituted crown ether is added to a first solvent, and a first oxidizing agent is added and refluxed for 10-25 h to obtain a carboxyl-substituted crown ether; Carbonyl unsaturated acids and their derivatives are added to monohydroxy substituted crown ethers, and the reaction is carried out for 2-8 hours to obtain ester-substituted crown ethers. The monohydroxy-substituted crown ether is stirred and refluxed with a halogenating agent in a reaction flask to obtain a halogen-substituted crown ether. The halogen-substituted crown ether and the polyether macromonomer or ester macromonomer are dissolved in the first solvent, and an acid-binding agent is added dropwise to obtain a polyether-substituted crown ether. Step 2: Preparation of functionalized polyamides: Polyacids and polyamines are stirred in a reaction flask and reacted under high temperature and vacuum for 1-5 hours to obtain polyamides. The polyamides are dissolved in a second solvent, an inorganic salt is added, and after precipitation, the solid obtained by filtration is the functionalized polyamide. Step 3: Preparation of rotaxane-type polycarboxylate superplasticizer: Functionalized polyamide, carboxyl-substituted crown ether, and polyether-substituted crown ether are dissolved in a third solvent, stirred, and then evaporated to dryness to obtain a solid; the solid is reacted with an end-capping agent under alkaline conditions for 2-8 hours to obtain a polycarboxylate superplasticizer with dynamic self-regulating ability; The carbonyl unsaturated acid and its derivatives are any one or more combinations of acrylic acid, sodium acrylate, methacrylic acid, sodium methacrylate, maleic acid, sodium maleate, acrylamide, methacrylamide, N-ethylacrylamide, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxy-n-butyl methacrylate, 2-vinylbenzoic acid, 2-vinylphenylacetic acid, and methyl 2-vinylbenzoate.

3. The method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability according to claim 2, characterized in that: The glycol compound is any one or a combination of pentaethylene glycol, hexaethylene glycol, and heptaethylene glycol; the alkaline solution is any one or a combination of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, silver hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, diethylamine, triethylamine, pyridine, and quaternary ammonium bases.

4. The method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability according to claim 2, characterized in that: The triol compound in step one is any one or a combination of 1,2,3-propanetriol, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,3-pentanetriol, 1,2,4-pentanetriol, 1,2,5-pentanetriol, and 1,3,5-pentanetriol.

5. The method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability according to claim 2, characterized in that: The first solvent is any one or a combination of acetonitrile, methanol, ethanol, tert-butanol, acetone, dichloromethane (DCM), chloroform, benzene, toluene, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and 1,2-dichloroethane; the first catalyst is any one or a combination of potassium carbonate, calcium carbonate, and barium carbonate; and the first oxidant is any one or a combination of potassium permanganate, pyridinium dichromate, chromium trioxide, potassium dichromate, and ruthenium tetroxide.

6. The method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability according to claim 2, characterized in that: The halogenating agent is any one or a combination of hydrogen fluoride, hydrogen bromide, hydrogen iodide, phosphorus tribromide, phosphorus trichloride, thionyl chloride, hypobromic acid, hypochlorous acid, ferric chloride, and ferric tribromide; the polyether macromonomer or ester macromonomer is any one or a combination of polyethylene glycol, methyl allyl polyoxyethylene ether, isopentenyl polyoxyethylene ether, polyethylene glycol methacrylate, polyethylene glycol methacrylate, and methoxy polyethylene glycol acrylate.

7. The method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability according to claim 2, characterized in that: The acid-binding agent is any one or a combination of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide, silver hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, diethylamine, triethylamine, pyridine, 4-dimethylaminopyridine (DMAP), N,N'-dicyclohexylcarboimide (DCC), N,N-diisopropylethylamine, and quaternary ammonium bases.

8. The method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability according to claim 2, characterized in that: The polyacid is any one or a combination of malonic acid, succinic acid, and glutaric acid; the polyamine is any one or a combination of two of ethylenediamine, propylenediamine, and butylenediamine; the second solvent is a composite solvent formed by mixing a fourth solvent (a combination of water, methanol, ethanol, n-butanol, isobutanol, tert-butanol, propylene glycol methyl ether, or propylene glycol ethyl ether) with water and a co-solvent; wherein the co-solvent is any one or a combination of two of DMF, acetonitrile, ethanesulfonyl acetonitrile, or acetamide; the volume ratio of water, the fourth solvent, and the co-solvent in the second solvent is 1:(3~6):(0.1~0.5); the inorganic salt is any one or a combination of potassium hexafluorophosphate, potassium chloride, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

9. The method for preparing a polycarboxylate superplasticizer with dynamic self-regulating capability according to claim 2, characterized in that: The third solvent is a composite solvent formed by mixing a fourth solvent, which is any one or more of water, methanol, ethanol, n-butanol, isobutanol, tert-butanol, propylene glycol methyl ether or propylene glycol ethyl ether, with water and a co-solvent; wherein the co-solvent is any one or more of DMF, acetonitrile, ethanesulfonyl acetonitrile or acetamide; and the end-capping agent is any one or more of bromoanthracene, iodoanthracene, and chloroanthracene.

Images