A kind of high molecular weight polyacrylamide and preparation method thereof
By adding specific additives to the polyacrylamide production process and controlling the reaction conditions, the problems of low solid content and insufficient molecular chain stability are solved, high relative molecular mass and stability are achieved, and it is suitable for large-scale industrial production.
Patent Information
- Application Number
- CN202411985311.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-04
AI Technical Summary
In the existing polyacrylamide production process, the solid content is low and the molecular chain stability is insufficient, making imidation reactions prone to occur, resulting in unstable performance and difficult to meet the industry's demand for high relative molecular mass and stability.
High molecular weight polyacrylamide emulsion was prepared by adding amine methylated plant polyphenols and n-butanol to the aqueous phase, and a specific ratio of 4-vinylpyridine, divinylbenzene and dodecyl acrylate to the oil phase to control the polymerization reaction conditions.
It significantly improves the solid content and molecular chain stability of polyacrylamide emulsion, enhances flocculation efficiency, and is suitable for large-scale industrial production.
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Abstract
Description
Technical Field
[0001] The invention relates to polyacrylamide and a preparation method thereof, belonging to the field of high molecular polymer preparation. Background Art
[0002] Polyacrylamide (PAM for short) is a water-soluble polymer with functional properties such as flocculation, thickening, shear resistance, drag reduction, and dispersibility. It plays an increasingly important role in modern industry and life. In particular, high molecular weight polymers are widely used in industrial fields such as sewage treatment, adhesives, coatings, papermaking, and oil drilling as flocculants, thickeners, and enhancers.
[0003] The production of polyacrylamide is to use acrylamide aqueous solution as raw material, under the action of initiator, carry out polymerization reaction, and the polyacrylamide block generated after the reaction is completed is cut, granulated, dried, and crushed to finally obtain the polyacrylamide product, and its key process is polymerization reaction. At present, the production method of polyacrylamide at home and abroad mainly includes copolymerization polymerization, homopolymerization and post-hydrolysis and pre-adding alkali co-hydrolysis polymerization, reverse emulsion polymerization and other processes. However, due to the limitation of process conditions, the solid content in the aqueous solution polymerization product is low, and imidization reaction is easy to occur, gel is generated, and polyacrylamide with high relative molecular weight cannot be obtained. And the molecular chain stability of the polyacrylamide obtained is insufficient, and the viscosity decreases after being illuminated, and the performance is impaired. With the development of industry, there is an urgent need for a water-soluble polymer latex with stable quality, good flocculation effect, high relative molecular weight and high solid content.
[0004] Therefore, the present invention aims to develop a method for preparing polyacrylamide with a simple process, stable molecular chain structure of the polymerization product and high molecular weight, which is easy for large-scale industrial production. Summary of the invention
[0005] In view of the above technical problems, the inventors provide a high molecular weight polyacrylamide and a preparation method thereof. The preparation method is specifically achieved through the following technical solutions:
[0006] One aspect of the present invention provides a method for preparing high molecular weight polyacrylamide, comprising the following steps:
[0007] Water phase: Add acrylic acid, acrylamide, aminomethylated plant polyphenols, n-butanol and sodium acetate to water, mix, stir to fully dissolve, and add liquid alkali to adjust the pH value of the system;
[0008] Oil phase: Mix Span, white oil, 4-vinylpyridine, divinylbenzene and acrylic esters and stir until fully dissolved;
[0009] The aqueous phase is added to the oil phase, and the mixture is sealed and stirred at a high speed for pre-emulsification; after the pre-emulsification, the stirring speed is reduced, nitrogen is introduced to drive out oxygen, an initiator is added to initiate polymerization, and after the polymerization, an inverting agent is added and stirred evenly to obtain a high molecular weight polyacrylamide emulsion.
[0010] The preparation method further comprises preparing raw materials according to the following mass fractions: 15-25 parts of acrylic acid, 12-15 parts of acrylamide, 5-10 parts of aminomethylated plant polyphenols, 3-8 parts of n-butanol, 5-10 parts of sodium acetate, 25-40 parts of water; 1.5-5 parts of Span, 10-25 parts of white oil, 1-3 parts of 4-vinylpyridine, 1-3 parts of divinylbenzene, 2-5 parts of acrylates, 0.01-1 parts of initiator, and the amount of reverse agent added accounts for 1 to 3% of the total weight of the high molecular weight polyacrylamide emulsion.
[0011] The invention adds aminomethylated plant polyphenols and n-butanol into the water phase and simultaneously adds 4-vinylpyridine, divinylbenzene and acrylic esters in a specific proportion into the oil phase, thereby increasing the molecular weight of polyacrylamide, improving the solid content of the polyacrylamide emulsion, enhancing the stability of the polyacrylamide emulsion and significantly improving the flocculation efficiency of the polyacrylamide.
[0012] Preferably, the initiator is potassium persulfate and sodium bisulfite in a mass ratio of 7:5.
[0013] Preferably, the acrylic acid ester is one or more of dodecamethyl acrylate, methacrylate, hexafluorobutyl acrylate, tridecyl methacrylate, and hexafluorobutyl methacrylate.
[0014] Preferably, after the polymerization reaction is completed, the temperature is lowered to below 40°C, an inverting agent is added and stirred for 30-60 minutes, and the material temperature is controlled not to be higher than 25°C.
[0015] Preferably, the temperature in the aqueous phase system is controlled to be no greater than 30° C., the pH value is 6-8, and the reaction time is 1-1.5 h.
[0016] Preferably, the polymerization temperature is 40-90°C.
[0017] Preferably, the mass concentration of the liquid caustic soda is 10-50% of a sodium hydroxide aqueous solution.
[0018] Preferably, the preparation method of the aminomethylated plant polyphenols is as follows: materials with a mass ratio of plant polyphenols: dimethylamine: formaldehyde = 1:2:3.5 are added to water and mixed evenly, then a 10% by volume acetic acid solution is added to make the acetic acid concentration be 0.03%, and the mixture is reacted at 50-70° C. under nitrogen protection for 2-5 hours, and the obtained reaction product is freeze-dried to obtain the aminomethylated plant polyphenols.
[0019] Preferably, the plant polyphenols are selected from tannin or curcumin.
[0020] Another aspect of the present invention provides a high molecular weight polyacrylamide prepared by any of the above methods.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] (1) The polyacrylamide emulsion of the present invention has the advantages of simple production process, fast dissolution rate, high relative molecular weight and narrow distribution, less residual monomer, low viscosity during polymerization reaction, easy heat dissipation and control, etc., and is suitable for large-scale production.
[0023] (2) The polyacrylamide emulsion prepared by the method of the present invention has high relative molecular mass, stable quality and high solid content. DETAILED DESCRIPTION
[0024] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0025] The present invention provides a method for preparing high molecular weight polyacrylamide, comprising the following steps:
[0026] (1) Aqueous phase: add 15-25 parts of acrylic acid, 12-15 parts of acrylamide, 5-10 parts of aminomethylated plant polyphenols, 3-8 parts of n-butanol and 5-10 parts of sodium acetate to 25-40 parts of water, stir to fully dissolve, control the temperature to be no more than 30°C, add liquid caustic soda to adjust the pH value of the aqueous phase system to 6-8, and neutralize for 1-1.5 hours; the mass concentration of the liquid caustic soda is 10-50% of sodium hydroxide aqueous solution, and cool the material temperature in the aqueous phase system to be between 10-15°C; preferably, the plant polyphenols are selected from tannins or curcumin.
[0027] (2) Oil phase: Span, white oil, 4-vinylpyridine, divinylbenzene and acrylates are mixed and stirred to fully dissolve; preferably, the acrylates are one or more of dodecamethyl acrylate, methacrylate, hexafluorobutyl acrylate, tridecyl methacrylate and hexafluorobutyl methacrylate;
[0028] (3) Slowly add the water phase to the oil phase and stir at a high speed to pre-emulsify. After the pre-emulsification is completed, reduce the stirring speed, introduce nitrogen to drive out oxygen, and control the flow rate to about 30m 3 / h, keep nitrogen flowing for 5min, add initiator to initiate polymerization, add reverse agent after polymerization (generally polymerization reaction time is about 3h), stir evenly to obtain high molecular weight polyacrylamide. Preferably, the polymerization temperature is 40-70°C.
[0029] In the following embodiment, the preparation method of the aminomethylated plant polyphenol is as follows: materials with a mass ratio of plant polyphenol: dimethylamine: formaldehyde = 1:2:3.5 are added to water and mixed evenly, and then a 10% volume fraction of acetic acid solution is added to make the concentration of acetic acid 0.03%, and the mixture is reacted at 65° C. under nitrogen protection for 3 hours, and the obtained reaction product is freeze-dried to obtain the aminomethylated plant polyphenol. The plant polyphenol is selected from curcumin.
[0030] In the following examples, Span 80 is selected, and the initiator is potassium persulfate and sodium bisulfite in a mass ratio of 7:5. The temperature in the aqueous phase system is controlled to be no more than 30°C, the pH value is about 7.8, and the reaction time is 1h. The mass concentration of liquid alkali is 48% sodium hydroxide aqueous solution; after adding the initiator, the reaction temperature is controlled to be no more than 90°C; the polymerization reaction temperature is 70°C. The acrylate is dodecamethyl acrylate; the reverse agent is AEO-10.
[0031] Example 1
[0032] A high molecular weight polyacrylamide emulsion, the preparation method comprises the steps of:
[0033] Aqueous phase: add 20 parts of acrylic acid, 13 parts of acrylamide, 8 parts of aminomethylated plant polyphenols, 5 parts of n-butanol and 8 parts of sodium acetate to 32 parts of water, mix and stir to fully dissolve, control the temperature not more than 30°C, add liquid alkali to adjust the pH value of the aqueous phase system to 7.8, and neutralize for 1 hour; the mass concentration of the liquid alkali is 48% of sodium hydroxide aqueous solution, and the temperature of the materials in the aqueous phase system is controlled by cooling to be no higher than 15°C.
[0034] Oil phase: Mix 2.5 parts of Span, 20 parts of white oil, 2 parts of 4-vinylpyridine, 2 parts of divinylbenzene, and 3 parts of dodecamethyl acrylate, stir to fully dissolve, and control the temperature of the material between 10~15℃;
[0035] Slowly add the water phase to the oil phase, and stir the pre-emulsion in a sealed high-speed mixer at a speed of 10000r / min for 0.5h. After the pre-emulsion is completed, reduce the stirring speed, introduce nitrogen to drive oxygen, and control the flow rate to about 30m 3 / h, keep nitrogen flowing for 5min, add 0.05 parts of initiator to initiate polymerization, control the reaction temperature at 70℃, and the reaction time for 3h; after the polymerization, cool down to below 40℃.
[0036] Add a reverse agent and stir evenly. The amount of the reverse agent added is 2% of the total weight of the high molecular weight polyacrylamide emulsion. Control the material temperature not higher than 25° C. to obtain a high molecular weight polyacrylamide emulsion.
[0037] Example 2
[0038] A high molecular weight polyacrylamide emulsion, the preparation method comprises the steps of:
[0039] Aqueous phase: add 15 parts of acrylic acid, 15 parts of acrylamide, 10 parts of aminomethylated plant polyphenols, 8 parts of n-butanol and 9 parts of sodium acetate to 29 parts of water, mix and stir to fully dissolve, control the temperature not more than 30°C, add liquid alkali to adjust the pH value of the aqueous phase system to 7.8, and neutralize for 1 hour; the mass concentration of the liquid alkali is 48% of sodium hydroxide aqueous solution, and the temperature of the materials in the aqueous phase system is controlled by cooling to be no higher than 15°C.
[0040] Oil phase: Mix 1.8 parts of Span, 23 parts of white oil, 3 parts of 4-vinylpyridine, 3 parts of divinylbenzene, and 2 parts of dodecamethyl acrylate, stir until fully dissolved, and control the temperature of the materials between 10 and 15°C;
[0041] Slowly add the water phase to the oil phase, and stir the pre-emulsion in a sealed high-speed mixer at a speed of 10000r / min for 0.5h. After the pre-emulsion is completed, reduce the stirring speed, introduce nitrogen to drive oxygen, and control the flow rate to about 30m 3 / h, keep nitrogen flowing for 5min, add 0.03 parts of initiator to initiate polymerization, control the reaction temperature to 70℃, and the reaction time to 3h; after the polymerization, cool down to below 40℃.
[0042] Add a reverse agent and stir evenly. The amount of the reverse agent added is 2% of the total weight of the high molecular weight polyacrylamide emulsion. Control the material temperature not higher than 25° C. to obtain a high molecular weight polyacrylamide emulsion.
[0043] Example 3
[0044] A high molecular weight polyacrylamide emulsion, the preparation method comprises the steps of:
[0045] Aqueous phase: add 25 parts of acrylic acid, 12 parts of acrylamide, 5 parts of aminomethylated plant polyphenols, 3 parts of n-butanol and 6 parts of sodium acetate to 37 parts of water, mix and stir to fully dissolve, control the temperature not more than 30°C, add liquid alkali to adjust the pH value of the aqueous phase system to 7.8, and neutralize for 1 hour; the mass concentration of the liquid alkali is 48% of sodium hydroxide aqueous solution, and the temperature of the materials in the aqueous phase system is controlled by cooling to be no higher than 15°C.
[0046] Oil phase: Mix 4.7 parts of Span, 17 parts of white oil, 1 part of 4-vinylpyridine, 1 part of divinylbenzene, and 5 parts of dodecamethyl acrylate, stir until fully dissolved, and control the temperature of the materials between 10 and 15°C;
[0047] Slowly add the water phase to the oil phase, and stir the pre-emulsion in a sealed high-speed mixer at a speed of 10000r / min for 0.5h. After the pre-emulsion is completed, reduce the stirring speed, introduce nitrogen to drive oxygen, and control the flow rate to about 30m 3 / h, keep nitrogen flowing for 5min, add 0.08 parts of initiator to initiate polymerization, control the reaction temperature at 70℃, and the reaction time is 3h; after the polymerization is completed, cool down to below 40℃.
[0048] Add a reverse agent and stir evenly. The amount of the reverse agent added is 2% of the total weight of the high molecular weight polyacrylamide emulsion. Control the material temperature not higher than 25° C. to obtain a high molecular weight polyacrylamide emulsion.
[0049] Comparative Example 1
[0050] A polyacrylamide is substantially the same as that in Example 1, except that an equal amount of dodecamethyl acrylate is used in the oil phase to replace 4-vinylpyridine and divinylbenzene.
[0051] Comparative Example 2
[0052] A polyacrylamide is substantially the same as that in Example 1, except that an equal amount of dodecamethyl acrylate is used in the oil phase to replace 4-vinylpyridine, that is, 5 parts of dodecamethyl acrylate and 0 parts of 4-vinylpyridine.
[0053] Comparative Example 3
[0054] A polyacrylamide is substantially the same as that in Example 1, except that an equal amount of dodecamethyl acrylate is used in place of divinylbenzene in the oil phase, that is, 5 parts of dodecamethyl acrylate and 0 parts of divinylbenzene.
[0055] Comparative Example 4
[0056] A polyacrylamide is substantially the same as that in Example 1, except that an equal amount of n-butanol is used to replace the aminomethylated plant polyphenols.
[0057] Comparative Example 5
[0058] A polyacrylamide is substantially the same as that in Example 1, except that an equal amount of plant polyphenols is used to replace the aminomethylated plant polyphenols.
[0059] Comparative Example 6
[0060] A polyacrylamide is substantially the same as that in Example 1, except that an equal amount of n-butanol is used to replace the aminomethylated plant polyphenols, and an equal amount of dodecamethyl acrylate is used to replace 4-vinylpyridine and divinylbenzene in the oil phase.
[0061] Test example
[0062] According to the national standard GB17514-2008, the viscosity average molecular weight of the polyacrylamide emulsions of Examples 1-3 and Comparative Examples 1-6 was tested, and the solid content, residual monomer content, and emulsion stratification of each polyacrylamide emulsion were tested. The test results are shown in Table 1:
[0063] Table 1 Viscosity average molecular weight, solid content, residual monomer content, and emulsion stratification of polyacrylamide emulsion
[0064]
[0065] The flocculation performance of the polyacrylamide emulsion is represented by the transmittance of the clear liquid filtered after the sludge is treated with the polymer, the flocculation rate and the sludge dehydration rate. The polyacrylamide emulsion obtained in Example 1 and Comparative Examples 1-6 is added dropwise to a certain amount of sludge, allowed to settle for 15 minutes, filtered for 10 minutes, and the clear liquid is measured for transmittance using a UV755B ultraviolet-visible spectrophotometer, and the volume of the obtained clear liquid is measured. The flocculation rate and the sludge dehydration rate are calculated using the following calculation formula: flocculation rate = (T-T0) / T×100%, T0: transmittance of the original sludge filtered clear liquid, T: transmittance of the sludge filtered clear liquid after flocculation; dehydration rate = V / V0×100%, V0: volume of the original sludge (mL), V: volume of the clear liquid obtained by filtering the sludge after flocculation (mL).
[0066]
[0067] From the above test results, the present invention can increase the molecular weight of polyacrylamide by adding aminomethylated plant polyphenols and n-butanol in the aqueous phase, and adding a specific proportion of 4-vinylpyridine, divinylbenzene, and dodecyl acrylate in the oil phase, while increasing the solid content of polyacrylamide emulsion, enhancing the stability of polyacrylamide emulsion, and significantly improving the flocculation efficiency of polyacrylamide. When the aqueous phase does not contain aminomethylated plant polyphenols or replaces aminomethylated plant polyphenols with plant polyphenols, or the oil phase does not contain 4-vinylpyridine or divinylbenzene, the various properties of polyacrylamide emulsion will be significantly affected. This is mainly because the aminomethylated plant polyphenols, n-butanol, and a specific proportion of 4-vinylpyridine, divinylbenzene, and dodecyl acrylate within the scope of the present invention can better synergistically improve the various properties of polyacrylamide emulsion.
[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing high molecular weight polyacrylamide, characterized in that: The steps include: Water phase: Add acrylic acid, acrylamide, aminomethylated plant polyphenols, n-butanol and sodium acetate to water, mix, stir to fully dissolve, and add liquid alkali to adjust the pH value of the system; Oil phase: Mix Span, white oil, 4-vinylpyridine, divinylbenzene and acrylic esters and stir until fully dissolved; The aqueous phase is added to the oil phase, and the mixture is sealed and stirred at a high speed for pre-emulsification; after the pre-emulsification, the stirring speed is reduced, nitrogen is introduced to drive out oxygen, an initiator is added to initiate polymerization, and after the polymerization, an inverting agent is added and stirred evenly to obtain a high molecular weight polyacrylamide emulsion.
2. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: The method comprises preparing raw materials according to the following mass fractions: 15-25 parts of acrylic acid, 12-15 parts of acrylamide, 5-10 parts of aminomethylated plant polyphenols, 3-8 parts of n-butanol, 5-10 parts of sodium acetate, 25-40 parts of water; 1.5-5 parts of Span, 10-25 parts of white oil, 1-3 parts of 4-vinylpyridine, 1-3 parts of divinylbenzene, 2-5 parts of acrylic esters; 0.01-1 parts of initiator; and the added amount of the reverse agent accounts for 1-3% of the total weight of the high molecular weight polyacrylamide emulsion.
3. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: The initiator is potassium persulfate and sodium bisulfite in a mass ratio of 7:
5.
4. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: The acrylic acid esters are one or more of dodecamethyl acrylate, methacrylate, hexafluorobutyl acrylate, tridecyl methacrylate, and hexafluorobutyl methacrylate.
5. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: After the polymerization reaction is completed, the temperature is lowered to below 40°C, an inverting agent is added and stirred for 30-60 minutes, and the material temperature is controlled not to be higher than 25°C.
6. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: The temperature in the aqueous phase system is controlled to be no greater than 30°C, the pH value is 6-8, and the reaction time is 1-1.5h.
7. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: The polymerization temperature is 40-90°C.
8. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: The mass concentration of liquid alkali is 10-50% sodium hydroxide aqueous solution.
9. The method for preparing a high molecular weight polyacrylamide according to claim 1, characterized in that: The preparation method of the aminomethylated plant polyphenols comprises the following steps: adding materials with a mass ratio of plant polyphenols: dimethylamine: formaldehyde = 1:2:3.5 into water and mixing them evenly, adding an acetic acid solution with a volume fraction of 10% to make the concentration of acetic acid 0.03%, reacting at 50-70° C. under nitrogen protection for 2-5 hours, and freeze-drying the obtained reaction product to obtain the aminomethylated plant polyphenols.
10. A high molecular weight polyacrylamide prepared according to the method of any one of claims 1 to 7.