Hydrolysis-resistant polyacrylamide gel

Abstract

The invention relates to hydrolysis-resistant polyacrylamide gel, which relates to the technical field of high polymer materials and comprises the following components in parts by mass: 50 to 70 parts of composite acrylamide monomer, 10 to 20 parts of comonomer, 0.75 to 1.5 parts of initiator and 3 to 8 parts of stabilizer. The hydrolysis-resistant polyacrylamide gel is prepared by the following steps: dispersing a composite acrylamide monomer, a comonomer and a stabilizer into a solvent, and stirring to obtain a mixed solution; the preparation method comprises the following steps: respectively preparing an initiator ammonium persulfate solution and a sodium hydrogen sulfite solution into aqueous solutions, sequentially adding the ammonium persulfate solution and the sodium hydrogen sulfite solution at intervals under the conditions of neutral gas protection and stirring, and carrying out a stirring reaction to obtain a gel solution; and pouring the gel solution into a mold, heating, standing, curing, taking out, and washing to obtain the hydrolysis-resistant polyacrylamide gel. The polyacrylamide gel has the effect of improving the hydrolysis resistance of the polyacrylamide gel, and the gel has high strength and good stability.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a hydrolysis-resistant polyacrylamide gel. Background Art

[0002] As an important polymer material, polyacrylamide gel is widely used in biochemistry, environmental science and industrial production. It has good transparency, mechanical strength and porosity, and can effectively separate and purify samples. However, traditional polyacrylamide gel has certain limitations in practical applications, especially in terms of hydrolytic stability, which limits its effectiveness in certain special environments.

[0003] In order to improve the performance of polyacrylamide gel, various methods are usually used in the prior art to enhance its hydrolysis resistance. However, in complex and changeable actual application scenarios, traditional improvement measures often fail to take into account the requirements of long-term stability and comprehensive performance. Although the hydrolysis resistance of the gel can be improved in the short term, it is still prone to structural damage and performance degradation during long-term use, resulting in a shortened effective life of the gel, which cannot meet high-standard application requirements, so it needs to be improved. Summary of the invention

[0004] In order to improve the hydrolysis resistance of the gel, the present application provides a hydrolysis-resistant polyacrylamide gel.

[0005] The hydrolysis-resistant polyacrylamide gel provided in the present application adopts the following technical solution: A hydrolysis-resistant polyacrylamide gel, the preparation raw materials include the following components in parts by weight: Composite acrylamide monomer 50-70 parts Comonomer 10-20 parts Initiator 0.75-1.5 parts 3-8 parts of stabilizer.

[0006] The composite acrylamide monomer serves as the main building unit, and multiple components cooperate with each other to give the gel network rich cross-linking sites, strengthen the internal structure, and enable the gel to effectively resist external force impact when facing complex environments, thereby improving the strength of the gel; the copolymer monomer optimizes the molecular structure of the gel, fills and reinforces the gaps between polymer chains, and works together with the composite acrylamide monomer to block the invasion path of water molecules, significantly enhancing the hydrolysis resistance and ensuring that the gel maintains a stable structure for a long time in a humid or even water environment; the initiator accurately controls the polymerization reaction process, promotes the efficient conversion of monomers into polymers, ensures the regularity and density of the gel structure, and thus improves the stability of the gel; the stabilizer contains rich active groups that can chelate metal ions and reduce the occurrence of hydrolysis reactions, thereby improving the hydrolysis resistance of polyacrylamide gel.

[0007] Preferably, the composite acrylamide monomer includes 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethyl acrylamide and N-isopropyl acrylamide.

[0008] 2-Acrylamide-2-methylpropanesulfonic acid has a strongly hydrophilic sulfonic acid group. During polymerization, the sulfonic acid group can not only promote the dissolution and dispersion of the monomer in the aqueous system, so that the reaction can proceed evenly, but also attract water molecules to form a hydration layer after the gel is formed, blocking external hydrolysis factors and enhancing the anti-hydrolysis performance; the hydroxyethyl group in the N-hydroxyethylacrylamide molecule can participate in the formation of hydrogen bonds, strengthen the interaction between monomers, promote the densification of the gel network, and improve the gel strength. At the same time, hydrogen bonds can buffer energy changes during temperature fluctuations, stabilize the gel structure, and ensure thermal stability; N-isopropylacrylamide introduces a certain hydrophobicity with its special isopropyl structure, cleverly balances with the hydrophilic groups of other monomers, optimizes the microenvironment inside the gel, adjusts the swelling performance of the gel, and enables it to maintain a good shape under different humidity conditions. At the same time, this unique structure also gives the gel a certain temperature sensitivity, further adapting to the changing external environment. The three complement each other to improve the anti-hydrolysis performance, strength and stability of polyacrylamide gel.

[0009] Preferably, the mass ratio of the 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethylacrylamide and N-isopropylacrylamide is (3.6-5.4):1:1.

[0010] Compounding acrylamide monomers according to the above mass ratio can effectively improve the hydrolysis resistance, strength and stability of polyacrylamide gel.

[0011] Preferably, the comonomer comprises N,N-methylenebisacrylamide and a long-chain alkyl gemini quaternary ammonium salt.

[0012] The double bonds at both ends of the N,N-methylenebisacrylamide molecule can react chemically with the composite acrylamide monomer and other components during the polymerization process, efficiently construct a tight and regular three-dimensional network structure, enhance the mechanical strength of the gel, and enable it to withstand greater external forces without being easily deformed or damaged; the long-chain alkyl gemini quaternary ammonium salt contains two quaternary ammonium salt groups and a long-chain alkyl structure, which can give it stronger electrostatic adsorption ability and intermolecular synergy; during the polymerization process, the long-chain alkyl gemini quaternary ammonium salt can be more closely intertwined with the composite acrylamide monomer, N,N-methylenebisacrylamide, etc., and optimize the hydrophilic and hydrophobic balance inside the gel by virtue of the hydrophobicity of the long-chain alkyl, build a denser protective barrier, effectively block the invasion of external water molecules, and enhance the anti-hydrolysis performance; at the same time, its double quaternary ammonium salt group forms a multi-point charge adsorption center in the gel network, which not only enhances the adsorption efficiency of oppositely charged substances, but also produces a wider interaction with other ions or polar groups in the system, stabilizes the gel structure, and improves the mechanical strength, so that the gel always maintains good anti-hydrolysis performance, high strength and good stability under complex and changeable application environments.

[0013] Preferably, the raw materials for preparing the long-chain alkyl gemini quaternary ammonium salt include long-chain alkyl diamine, epoxy quaternary ammonium salt and acyl chloride.

[0014] Long-chain alkyl diamines have long-chain hydrophobic structural units, which can effectively increase the molecular distance, reduce the free water content inside the gel, and improve the hydrolysis resistance from the source; epoxy quaternary ammonium salts contain highly active epoxy groups, which can react rapidly with long-chain alkyl diamines to build a stable connection structure, strengthen the uniformity of its positive charge distribution, and thereby improve the ability to remove negatively charged impurities in the system, ensure the chemical purity of the gel, and promote the improvement of hydrolysis resistance; acyl chlorides can introduce active groups, so that long-chain alkyl gemini quaternary ammonium salts can undergo cross-linking reactions with polyacrylamide, increase the cross-linking density of the gel, and enable the quaternary ammonium salt molecules to better combine with polyacrylamide to exert their performance and improve the stability of the gel; the long-chain alkyl gemini quaternary ammonium salts prepared by the three enhance the comprehensive properties of the gel, such as hydrolysis resistance, strength and stability, and lay a solid foundation for the gel to have long-lasting excellent performance in complex and harsh application environments.

[0015] Preferably, the long-chain alkyl gemini quaternary ammonium salt is prepared by the following steps: Dispersing a long-chain alkyl diamine in toluene to obtain a diamine solution; dispersing an epoxy quaternary ammonium salt in toluene to obtain a quaternary ammonium salt solution; adding the quaternary ammonium salt solution to the epoxy quaternary ammonium salt solution under stirring, heating and stirring to react after the addition is completed, and cooling to obtain a preliminary product solution; adding triethylamine to the preliminary product solution, adding octanoyl chloride under ice-water bath conditions, stirring to react after the addition is completed, and obtaining a reaction mixture; pouring the reaction mixture into ice water to precipitate the product, filtering and washing to obtain a crude product, recrystallizing the crude product to obtain a product, and vacuum drying the product to obtain a long-chain alkyl gemini quaternary ammonium salt.

[0016] The long-chain alkyl gemini quaternary ammonium salt prepared according to the above steps can effectively improve the hydrolysis resistance, strength and stability of polyacrylamide gel.

[0017] Preferably, the initiator comprises ammonium persulfate and sodium bisulfite.

[0018] As a strong oxidant, ammonium persulfate can spontaneously decompose at a certain temperature to produce highly active sulfate free radicals, initiating the starting step of a chain polymerization reaction; sodium bisulfite can undergo a redox reaction with ammonium persulfate, continuously and stably replenishing new free radicals for the system; a reasonable combination of the two can accurately control the generation rate of free radicals, prevent a large number of free radicals from appearing instantly, and allow the reaction to proceed smoothly and orderly, thereby constructing a gel system with a regular structure and uniform cross-linking, ultimately giving the gel excellent hydrolysis resistance, high strength and good stability.

[0019] Preferably, the raw materials for preparing the stabilizer include diethylenetriaminepentaacetic acid and p-hydroxybenzoic acid.

[0020] The molecular structure of diethylenetriamine pentaacetic acid is unique, rich in multiple amino and carboxyl groups, and has strong chelating ability. It can capture metal ion impurities in the system, effectively inhibit the occurrence of side reactions, and improve the hydrolysis resistance of polyacrylamide gel; the carboxyl group of p-hydroxybenzoic acid can react with the amino group of diethylenetriamine pentaacetic acid to optimize the structure of the stabilizer itself and enhance stability. The introduced phenolic hydroxyl group can improve the compatibility of the stabilizer, so that it can be better dispersed in the aqueous environment of the gel system, improve antioxidant properties, block oxidation reactions, and cooperate with diethylenetriamine pentaacetic acid to protect the gel network, ensuring that the gel can resist erosion under complex conditions such as humidity and high temperature, and maintain good hydrolysis resistance, high strength and stability for a long time.

[0021] Preferably, the mass ratio of diethylenetriaminepentaacetic acid to p-hydroxybenzoic acid is 1:(0.4-0.7).

[0022] The stabilizer prepared according to the above mass ratio can effectively improve the hydrolysis resistance, strength and stability of polyacrylamide gel.

[0023] Preferably, the hydrolysis-resistant polyacrylamide gel is prepared by the following steps: The composite acrylamide monomer, comonomer and stabilizer are dispersed in a solvent and stirred to obtain a mixed solution; initiators ammonium persulfate and sodium bisulfite are respectively prepared into aqueous solutions, and under the condition of neutral gas protection and stirring, the ammonium persulfate solution is added to the mixed solution, and the reaction temperature is controlled. After the addition is completed, the sodium bisulfite solution is added, and the reaction is stirred to obtain a gel solution; the gel solution is poured into a mold, heated and allowed to stand for solidification, and then taken out, and washed to obtain a hydrolysis-resistant polyacrylamide gel.

[0024] The polyacrylamide gel prepared according to the above steps has good hydrolysis resistance, high strength and good stability, and can maintain good working performance for a long time in a complex application environment.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. The composite acrylamide monomer is used as the main building unit. Multiple components cooperate with each other to give the gel network rich cross-linking sites and strengthen the internal structure, so that the gel can effectively resist external force impact when facing complex environments, thereby improving the strength of the gel; the copolymer monomer optimizes the molecular structure of the gel, fills and reinforces the gaps between polymer chains, and works together with the composite acrylamide monomer to block the invasion path of water molecules, significantly enhance the hydrolysis resistance, and ensure that the gel maintains a stable structure for a long time in a humid or even water environment; the initiator accurately controls the polymerization reaction process, promotes the efficient conversion of monomers into polymers, ensures the regularity and density of the gel structure, and thus improves the stability of the gel; the stabilizer contains rich active groups that can chelate metal ions and reduce the occurrence of hydrolysis reactions, thereby improving the hydrolysis resistance of polyacrylamide gel.

[0026] 2. The double bonds at both ends of the N,N-methylenebisacrylamide molecule can react chemically with the composite acrylamide monomer and other components during the polymerization process, effectively building a tight and regular three-dimensional network structure, enhancing the mechanical strength of the gel, and enabling it to withstand greater external forces without being easily deformed or damaged; the long-chain alkyl gemini quaternary ammonium salt contains two quaternary ammonium salt groups and a long-chain alkyl structure, which can give it stronger electrostatic adsorption ability and intermolecular synergy; during the polymerization process, the long-chain alkyl gemini quaternary ammonium salt can more closely bind to the composite acrylamide monomer, N,N-methylenebisacrylamide Amines and other substances are intertwined with each other, and with the hydrophobicity of long-chain alkyl groups, the hydrophilic and hydrophobic balance inside the gel is optimized, a denser protective barrier is constructed, which effectively blocks the invasion of external water molecules and enhances the anti-hydrolysis performance; at the same time, its diquaternary ammonium salt groups form multi-point charge adsorption centers in the gel network, which not only enhances the adsorption efficiency of oppositely charged substances, but also produces more extensive interactions with other ions or polar groups in the system, stabilizes the gel structure, and enhances the mechanical strength, so that the gel always maintains good anti-hydrolysis performance, high strength and good stability in complex and changeable application environments.

[0027] 3. The molecular structure of diethylenetriamine pentaacetic acid is unique, rich in multiple amino and carboxyl groups, and has strong chelating ability. It can capture metal ion impurities in the system, effectively inhibit the occurrence of side reactions, and improve the hydrolysis resistance of polyacrylamide gel; the carboxyl group of p-hydroxybenzoic acid can react with the amino group of diethylenetriamine pentaacetic acid to optimize the structure of the stabilizer itself and enhance stability. The introduced phenolic hydroxyl group can improve the compatibility of the stabilizer, so that it can be better dispersed in the aqueous environment of the gel system, improve antioxidant properties, block oxidation reactions, and cooperate with diethylenetriamine pentaacetic acid to protect the gel network, ensuring that the gel can resist erosion under complex conditions such as humidity and high temperature, and maintain good hydrolysis resistance, high strength and stability for a long time. DETAILED DESCRIPTION

[0028] The present application discloses a hydrolysis-resistant polyacrylamide gel. The raw materials used in the present application can be obtained from commercially available raw materials unless otherwise specified. The present application is further described in detail below in conjunction with the examples: Raw materials description: long-chain alkyl diamine is decanediamine (CAS No.: 646-25-3), epoxy quaternary ammonium salt is epoxypropyl trimethyl ammonium chloride (CAS No.: 3033-77-0), triethylamine (CAS No.: 121-44-8), octanoyl chloride (CAS No.: 111-64-8), diethylenetriamine pentaacetic acid (CAS No.: 67-43-6), p-hydroxybenzoic acid (CAS No.: 99-96-7), 2-acrylamido-2-methylpropanesulfonate Acid (CAS No.: 15214-89-8), N-hydroxyethyl acrylamide (CAS No.: 7646-67-5), N-isopropyl acrylamide (CAS No.: 2210-25-5), N,N-methylenebisacrylamide (CAS No.: 110-26-9), ammonium persulfate (CAS No.: 7727-54-0), sodium bisulfite (CAS No.: 7631-90-5), decylamine (CAS No.: 2016-57-1).

[0029] Example 1 Preparation of long-chain alkyl gemini quaternary ammonium salts Disperse 12.5g of long-chain alkyl diamine in 40mL of toluene to obtain a diamine solution; disperse 18.75g of epoxy quaternary ammonium salt in 100mL of toluene to obtain a quaternary ammonium salt solution; add the quaternary ammonium salt solution to the diamine solution at a stirring speed of 400rpm, complete the addition within 1h, stir and react at 45°C at a speed of 300rpm for 6h after the addition is completed, and cool to 30°C to obtain a preliminary product solution; add 7g of triethylamine as an acid binding agent to the preliminary product solution, add 8.75g of octanoyl chloride within 30min under ice-water bath conditions, stir and react at a speed of 300rpm for 3h after the addition is completed, and obtain a reaction mixture; pour the reaction mixture into 200mL of ice water to precipitate the product, filter, wash the filter cake with deionized water for 3 times, obtain a crude product, recrystallize the crude product with 75% ethanol aqueous solution to obtain a product, and vacuum dry the product at 50°C to obtain a long-chain alkyl gemini quaternary ammonium salt.

[0030] Preparation of stabilizer 7.14 g of diethylenetriaminepentaacetic acid is dispersed in 50 mL of anhydrous ethanol to obtain a diethylenetriaminepentaacetic acid solution; 2.86 g of p-hydroxybenzoic acid is dissolved in 20 mL of anhydrous ethanol to obtain a p-hydroxybenzoic acid solution; under a stirring condition of 300 rpm, the p-hydroxybenzoic acid solution is added to the diethylenetriaminepentaacetic acid solution, and the addition is completed within 30 minutes. The temperature is controlled to 60° C. for reaction for 5 hours, and the temperature is raised to 75° C. for reflux reaction for 3 hours. After cooling to 30° C., the solvent is removed by rotary evaporation to obtain a crude product, and the crude product is recrystallized using a 75% ethanol aqueous solution to obtain a stabilizer.

[0031] Preparation of polyacrylamide gel 50g of composite acrylamide monomer, 10g of comonomer and 3g of stabilizer were dispersed in a solvent and stirred at a speed of 500rpm for 30min to obtain a mixed solution. The mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethyl acrylamide and N-isopropyl acrylamide in the composite acrylamide monomer was 3.6:1:1, and the mass ratio of N,N-methylenebisacrylamide and long-chain alkyl gemini quaternary ammonium salt in the comonomer was 1:0.8; the amount of initiator was 0.75g, and the mass ratio of ammonium persulfate and sodium bisulfite in the initiator was 1:0.5. Ammonium persulfate was prepared into a concentrated The aqueous solution with a concentration of 15% is prepared, and sodium bisulfite is prepared into an aqueous solution with a concentration of 8%. Under nitrogen protection, the mixture is stirred at a speed of 200 rpm, and the ammonium persulfate solution is added to the mixed solution, and the addition is completed within 30 minutes. The temperature is controlled to be 40°C. After 5 minutes of the addition, the sodium bisulfite solution is added, and the addition is completed within 30 minutes. After the addition is completed, the stirring speed is maintained at 200 rpm for 4 hours to obtain a gel solution. The gel solution is poured into a mold, and it is allowed to stand and solidify at 50°C for 18 hours. After solidification, it is taken out and washed with deionized water to obtain a hydrolysis-resistant polyacrylamide gel.

[0032] Example 2 Preparation of long-chain alkyl gemini quaternary ammonium salts Disperse 12.5g of long-chain alkyl diamine in 40mL of toluene to obtain a diamine solution; disperse 18.75g of epoxy quaternary ammonium salt in 100mL of toluene to obtain a quaternary ammonium salt solution; add the quaternary ammonium salt solution to the diamine solution at a stirring speed of 400rpm, complete the addition within 1h, stir and react at 45°C at a speed of 300rpm for 6h after the addition is completed, and cool to 30°C to obtain a preliminary product solution; add 7g of triethylamine as an acid binding agent to the preliminary product solution, add 8.75g of octanoyl chloride within 30min under ice-water bath conditions, stir and react at a speed of 300rpm for 3h after the addition is completed, and obtain a reaction mixture; pour the reaction mixture into 200mL of ice water to precipitate the product, filter, wash the filter cake with deionized water for 3 times, obtain a crude product, recrystallize the crude product with 75% ethanol aqueous solution to obtain a product, and vacuum dry the product at 50°C to obtain a long-chain alkyl gemini quaternary ammonium salt.

[0033] Preparation of stabilizer Disperse 5.88 g of diethylenetriaminepentaacetic acid in 50 mL of anhydrous ethanol to obtain a diethylenetriaminepentaacetic acid solution; dissolve 4.12 g of p-hydroxybenzoic acid in 20 mL of anhydrous ethanol to obtain a p-hydroxybenzoic acid solution; add the p-hydroxybenzoic acid solution to the diethylenetriaminepentaacetic acid solution under stirring at 300 rpm, and complete the addition within 30 minutes. Control the temperature to 60° C. for reaction for 5 hours, heat to 75° C. for reflux reaction for 3 hours, and after cooling to 30° C., remove the solvent by rotary evaporation to obtain a crude product. The crude product is recrystallized using a 75% ethanol aqueous solution to obtain a stabilizer.

[0034] Preparation of polyacrylamide gel 70g of composite acrylamide monomer, 20g of comonomer and 8g of stabilizer were dispersed in a solvent and stirred at a speed of 500rpm for 30min to obtain a mixed solution. The mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethyl acrylamide and N-isopropyl acrylamide in the composite acrylamide monomer was 5.4:1:1, and the mass ratio of N,N-methylenebisacrylamide and long-chain alkyl gemini quaternary ammonium salt in the comonomer was 1:0.8; the amount of initiator was 1.5g, and the mass ratio of ammonium persulfate and sodium bisulfite in the initiator was 1:0.5. Ammonium persulfate was prepared into a concentrated The aqueous solution with a concentration of 15% is prepared, and sodium bisulfite is prepared into an aqueous solution with a concentration of 8%. Under nitrogen protection, the mixture is stirred at a speed of 200 rpm, and the ammonium persulfate solution is added to the mixed solution, and the addition is completed within 30 minutes. The temperature is controlled to be 40°C. After 5 minutes of the addition, the sodium bisulfite solution is added, and the addition is completed within 30 minutes. After the addition is completed, the stirring speed is maintained at 200 rpm for 4 hours to obtain a gel solution. The gel solution is poured into a mold, and it is allowed to stand and solidify at 50°C for 18 hours. After solidification, it is taken out and washed with deionized water to obtain a hydrolysis-resistant polyacrylamide gel.

[0035] Example 3 Preparation of long-chain alkyl gemini quaternary ammonium salts Disperse 12.5g of long-chain alkyl diamine in 40mL of toluene to obtain a diamine solution; disperse 18.75g of epoxy quaternary ammonium salt in 100mL of toluene to obtain a quaternary ammonium salt solution; add the quaternary ammonium salt solution to the diamine solution at a stirring speed of 400rpm, complete the addition within 1h, stir and react at 45°C at a speed of 300rpm for 6h after the addition is completed, and cool to 30°C to obtain a preliminary product solution; add 7g of triethylamine as an acid binding agent to the preliminary product solution, add 8.75g of octanoyl chloride within 30min under ice-water bath conditions, stir and react at a speed of 300rpm for 3h after the addition is completed, and obtain a reaction mixture; pour the reaction mixture into 200mL of ice water to precipitate the product, filter, wash the filter cake with deionized water for 3 times, obtain a crude product, recrystallize the crude product with 75% ethanol aqueous solution to obtain a product, and vacuum dry the product at 50°C to obtain a long-chain alkyl gemini quaternary ammonium salt.

[0036] Preparation of stabilizer Disperse 6.45 g of diethylenetriaminepentaacetic acid in 50 mL of anhydrous ethanol to obtain a diethylenetriaminepentaacetic acid solution; dissolve 3.55 g of p-hydroxybenzoic acid in 20 mL of anhydrous ethanol to obtain a p-hydroxybenzoic acid solution; add the p-hydroxybenzoic acid solution to the diethylenetriaminepentaacetic acid solution under a stirring condition of 300 rpm, and complete the addition within 30 minutes. Control the temperature to 60° C. for reaction for 5 hours, heat to 75° C. for reflux reaction for 3 hours, and after cooling to 30° C., remove the solvent by rotary evaporation to obtain a crude product. The crude product is recrystallized using a 75% ethanol aqueous solution to obtain a stabilizer.

[0037] Preparation of polyacrylamide gel 60g of composite acrylamide monomer, 15g of comonomer and 5.5g of stabilizer were dispersed in a solvent and stirred at a speed of 500rpm for 30min to obtain a mixed solution. The mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethyl acrylamide and N-isopropyl acrylamide in the composite acrylamide monomer was 4.51:1, and the mass ratio of N,N-methylenebisacrylamide and long-chain alkyl gemini quaternary ammonium salt in the comonomer was 1:0.8; the amount of initiator was 1.125g, and the mass ratio of ammonium persulfate and sodium bisulfite in the initiator was 1:0.5. The ammonium persulfate was prepared into The concentration of the aqueous solution is 15%, and the sodium bisulfite is prepared into an aqueous solution with a concentration of 8%. Under nitrogen protection, the ammonium persulfate solution is added to the mixed solution at a stirring speed of 200 rpm, and the addition is completed within 30 minutes. The temperature is controlled at 40°C. After 5 minutes of the addition, the sodium bisulfite solution is added, and the addition is completed within 30 minutes. After the addition is completed, the stirring speed is maintained at 200 rpm for 4 hours to obtain a gel solution. The gel solution is poured into a mold, and it is allowed to stand and solidify at 50°C for 18 hours. After solidification, it is taken out and washed with deionized water to obtain a hydrolysis-resistant polyacrylamide gel.

[0038] Example 4 Example 4 is based on Example 3. The only difference between Example 4 and Example 3 is that in Example 4, the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethylacrylamide and N-isopropylacrylamide is 2:1:1.

[0039] Example 5 Example 5 is based on Example 3. The only difference between Example 5 and Example 3 is that in Example 5, the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethylacrylamide and N-isopropylacrylamide is 7:1:1.

[0040] Example 6 Example 6 is based on Example 3, and the only difference between Example 6 and Example 3 is that N-hydroxyethyl acrylamide is not added in Example 6.

[0041] Example 7 Example 7 is based on Example 3, and the only difference between Example 7 and Example 3 is that N-isopropylacrylamide is not added in Example 7.

[0042] Example 8 Example 8 is based on Example 3. The only difference between Example 8 and Example 3 is that in Example 8, no acyl chloride is added when preparing the long-chain alkyl gemini quaternary ammonium salt.

[0043] Example 9 Example 9 is based on Example 3. The only difference between Example 9 and Example 3 is that in Example 9, the long-chain alkyl diamine is replaced by decylamine.

[0044] Example 10 Example 10 is based on Example 3. The only difference between Example 10 and Example 3 is that in Example 10, the amount of diethylenetriaminepentaacetic acid is 8.33 g, and the amount of p-hydroxybenzoic acid is 1.67 g.

[0045] Embodiment 11 Example 11 is based on Example 3. The only difference between Example 11 and Example 3 is that in Example 11, the amount of diethylenetriaminepentaacetic acid is 5.26 g, and the amount of p-hydroxybenzoic acid is 4.74 g.

[0046] Comparative Example 1 Comparative Example 1 is based on Example 3, and the only difference between Comparative Example 1 and Example 3 is that the comonomer in Comparative Example 1 is replaced by N,N-methylenebisacrylamide.

[0047] Comparative Example 2 Comparative Example 2 is based on Example 3, and the only difference between Comparative Example 2 and Example 3 is that the initiator in Comparative Example 2 is replaced by ammonium persulfate.

[0048] Comparative Example 3 Comparative Example 3 is based on Example 3, and the only difference between Comparative Example 3 and Example 3 is that the stabilizer in Comparative Example 3 is replaced by diethylenetriaminepentaacetic acid.

[0049] Performance testing (1) The "GB / T12005.6-1989 Determination of Hydrolysis Degree of Partially Hydrolyzed Polyacrylamide" was selected as the standard. The samples were cured for 7 days in an alkaline environment with a pH of 12, a high temperature of 80°C, and an environment containing 0.5 mg / L iron ions. The hydrolysis degree before and after curing was tested, and the rate of change of hydrolysis degree was calculated. Three samples were prepared for each sample, and the average value was taken after measurement. The results are recorded in Table 1.

[0050] (2) Strength test: The strength of the sample was calculated using a gel strength tester. Each sample was tested three times and the average value was taken after measurement. The results are recorded in Table 1.

[0051] Table 1 Test results of polyacrylamide gel hydrolysis resistance, strength and stability As shown in Table 1, the alkaline hydrolysis rate of Examples 1-3 is less than 11.3%, the high temperature hydrolysis rate is less than 7.4%, the metal ion hydrolysis rate is less than 3.2%, and the strength is greater than 183 g / cm 2, thus it can be seen that the polyacrylamide gel prepared in the present application has good anti-hydrolysis performance, high strength and good stability.

[0052] As can be seen from Table 1, the only difference between Examples 4, 5, 6, and 7 and Example 3 is that the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethylacrylamide and N-isopropylacrylamide in Example 4 is 2:1:1, the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethylacrylamide and N-isopropylacrylamide in Example 5 is 7:1:1, N-hydroxyethylacrylamide is not added in Example 6, and N-isopropylacrylamide is not added in Example 7. Compared with Example 3, Examples 4, 5, 6, and 7 have reduced hydrolysis resistance, strength, and stability; this is because the ratio of each monomer in the composite acrylamide is changed, the balance of hydrophilic and hydrophobic interactions is broken, which will affect the arrangement of the gel network structure, and then affect the hydrolysis resistance, strength, and stability; reducing the components in the composite acrylamide monomer will further reduce the performance.

[0053] As can be seen from Table 1, the only difference between Examples 8 and 9 and Example 3 is that: in Example 8, no acyl chloride is added when preparing the long-chain alkyl gemini quaternary ammonium salt, and in Example 9, the long-chain alkyl diamine is replaced by decylamine. Compared with Example 3, Examples 8 and 9 have reduced hydrolysis resistance, strength and stability; this is because no acyl chloride is added, the introduction of acyl groups is lacking, the reaction activity decreases, and the crosslinking density of the gel decreases; if the long-chain alkyl diamine is replaced by decylamine, the synthesized product is not a gemini quaternary ammonium salt, the neutrality of the charge adsorption is reduced, and the interaction in the system is weakened, so that the hydrolysis resistance, strength and stability of the gel decrease.

[0054] As can be seen from Table 1, the only difference between Examples 10 and 11 and Example 3 is that the mass ratio of diethylenetriaminepentaacetic acid to p-hydroxybenzoic acid in Example 10 is 1:0.2, and the mass ratio of diethylenetriaminepentaacetic acid to p-hydroxybenzoic acid in Example 11 is 1:0.9. Compared with Example 3, the hydrolysis resistance, strength and stability of Examples 10 and 11 are reduced. This is because the mass ratio of diethylenetriaminepentaacetic acid to p-hydroxybenzoic acid is changed. Too much or too little p-hydroxybenzoic acid will affect the balance of performance, affect the metal ion chelation, and the compatibility and antioxidant properties with the gel network, so that the hydrolysis resistance, strength and stability of the gel are reduced.

[0055] As can be seen from Table 1, the only difference between Comparative Example 1 and Example 3 is that in Comparative Example 1, the comonomer is replaced with N, N-methylenebisacrylamide. Compared with Example 3, the hydrolysis resistance, strength and stability of Comparative Example 1 are reduced. This is because the comonomer is replaced with N, N-methylenebisacrylamide, the introduction of long-chain alkyl gemini quaternary ammonium salt is lacking, the crosslinking density inside the gel network is reduced, the interaction is weakened, and thus the stability is reduced, and the hydrolysis resistance and strength are reduced.

[0056] As can be seen from Table 1, the only difference between Comparative Example 2 and Example 3 is that the initiator in Comparative Example 2 is replaced by ammonium persulfate. Compared with Example 3, the hydrolysis resistance, strength and stability of Comparative Example 2 are reduced. This is because the uniformity and stability of the reaction system are weakened due to the lack of the regulating effect of sodium bisulfite, and the performance of the gel network is affected, thereby reducing the hydrolysis resistance, strength and stability.

[0057] As can be seen from Table 1, the only difference between Comparative Example 3 and Example 3 is that the stabilizer in Comparative Example 3 is replaced with diethylenetriaminepentaacetic acid. Compared with Example 3, the hydrolysis resistance, strength and stability of Comparative Example 3 are reduced; this is because the lack of introduction of phenol groups reduces the antioxidant performance and compatibility, thereby reducing the hydrolysis resistance, strength and stability.

[0058] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of ​​the present application. The technical scope of the present application is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A hydrolysis-resistant polyacrylamide gel, characterized in that: The raw materials for preparation include the following components in parts by weight: Composite acrylamide monomer 50-70 parts Comonomer 10-20 parts Initiator 0.75-1.5 parts 3-8 parts of stabilizer.

2. The hydrolysis-resistant polyacrylamide gel according to claim 1, characterized in that: The composite acrylamide monomer includes 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethyl acrylamide and N-isopropyl acrylamide.

3. The hydrolysis-resistant polyacrylamide gel according to claim 2, characterized in that: The mass ratio of the 2-acrylamido-2-methylpropanesulfonic acid, N-hydroxyethylacrylamide and N-isopropylacrylamide is (3.6-5.4):1:

1.

4. The hydrolysis-resistant polyacrylamide gel according to claim 1, characterized in that: The comonomers include N,N-methylenebisacrylamide and long-chain alkyl gemini quaternary ammonium salt.

5. The hydrolysis-resistant polyacrylamide gel according to claim 4, characterized in that: The raw materials for preparing the long-chain alkyl gemini quaternary ammonium salt include long-chain alkyl diamine, epoxy quaternary ammonium salt and acyl chloride.

6. The hydrolysis-resistant polyacrylamide gel according to claim 5, characterized in that: The long-chain alkyl gemini quaternary ammonium salt is prepared by the following steps: Dispersing a long-chain alkyl diamine in toluene to obtain a diamine solution; dispersing an epoxy quaternary ammonium salt in toluene to obtain a quaternary ammonium salt solution; adding the quaternary ammonium salt solution to the epoxy quaternary ammonium salt solution under stirring, heating and stirring to react after the addition is completed, and cooling to obtain a preliminary product solution; Add triethylamine to the preliminary product solution, add octanoyl chloride under ice-water bath conditions, stir the reaction after the addition is complete to obtain a reaction mixture; pour the reaction mixture into ice water to precipitate the product, filter and wash to obtain a crude product, recrystallize the crude product to obtain a product, and vacuum dry the product to obtain a long-chain alkyl gemini quaternary ammonium salt.

7. The hydrolysis-resistant polyacrylamide gel according to claim 1, characterized in that: The initiators include ammonium persulfate and sodium bisulfite.

8. The hydrolysis-resistant polyacrylamide gel according to claim 1, characterized in that: The raw materials for preparing the stabilizer include diethylenetriaminepentaacetic acid and p-hydroxybenzoic acid.

9. The hydrolysis-resistant polyacrylamide gel according to claim 8, characterized in that: The mass ratio of the diethylenetriaminepentaacetic acid to p-hydroxybenzoic acid is 1:(0.4-0.7).

10. A hydrolysis-resistant polyacrylamide gel according to any one of claims 1 to 9, characterized in that: The hydrolysis-resistant polyacrylamide gel is prepared by the following steps: The composite acrylamide monomer, comonomer and stabilizer are dispersed in a solvent and stirred to obtain a mixed solution; the initiators ammonium persulfate and sodium bisulfite are respectively prepared into aqueous solutions, and the ammonium persulfate solution is added to the mixed solution under the protection of a neutral gas and stirring, and the reaction temperature is controlled. After the addition is completed, the sodium bisulfite solution is added, and the reaction is stirred to obtain a gel solution; The gel solution is poured into a mold, heated and allowed to stand for solidification, then taken out and washed to obtain a hydrolysis-resistant polyacrylamide gel.

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