A polyacrylamide aqueous dispersion, its synthesis method and application

Abstract

The application discloses a kind of polyacrylamide aqueous dispersion and its synthesis method and application, it is related to polyacrylamide synthetic technical field;The synthesis method of polyacrylamide aqueous dispersion includes making the reaction system of acrylamide I, cationic monomer I, inorganic salt, stabilizer, easily hydrolyzed acrylate monomer and initiator I carries out reaction I, obtains the polyacrylamide aqueous dispersion;Wherein, the stabilizer is the cationic copolymer of polyacrylamide segment;The polyacrylamide aqueous dispersion prepared in the application has excellent stability, and no destabilization occurs when placed at room temperature for more than 6 months.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyacrylamide synthesis, in particular to a polyacrylamide aqueous dispersion and a synthesis method and application thereof. BACKGROUND

[0002] Polyacrylamide has good water solubility and high efficient viscosity increasing property, and is widely used in water treatment, oil extraction, papermaking, textile and many other fields. The aqueous dispersion polymerization is an important method for preparing polyacrylamide aqueous dispersion, which is prepared by polymerization of acrylamide in aqueous inorganic salt solution in the presence of a specific stabilizer.

[0003] At present, the biggest problem of preparing polyacrylamide aqueous dispersion by aqueous dispersion polymerization is that the apparent viscosity is large, resulting in poor stability of the aqueous dispersion. Generally, the conventional polyacrylamide aqueous dispersion will separate into layers after several weeks to several months. Reducing the concentration of polyacrylamide or appropriately increasing the concentration of inorganic salt can increase the apparent viscosity of the polyacrylamide aqueous dispersion. However, the concentration of polyacrylamide means that the content of effective substances in the dispersion is reduced; and appropriately increasing the concentration of inorganic salt often reduces the long-term storage stability of the polyacrylamide aqueous dispersion.

[0004] At present, the polyacrylamide aqueous dispersion with low apparent viscosity is a difficulty in the synthesis of polyacrylamide aqueous dispersion. SUMMARY

[0005] The present application aims at the problems existing in the synthesis of the prior art polyacrylamide aqueous dispersion, and prepares a polyacrylamide aqueous dispersion with low apparent viscosity by dispersion polymerization. The stabilizer for the dispersion polymerization is a cationic copolymer containing a polyacrylamide segment. Different from other methods, the present application introduces an acrylate monomer which is easily decomposed into anions during the synthesis of the cationic polyacrylamide aqueous dispersion, and the interaction between the anionic polyacrylic acid formed by in-situ hydrolysis and the cationic polyacrylamide obtains the polyacrylamide aqueous dispersion with low apparent viscosity.

[0006] To solve the above technical problems, the present application provides a synthesis method of a polyacrylamide aqueous dispersion, which comprises reacting a reaction system of acrylamide I, a cationic monomer I, an inorganic salt, a stabilizer, an easily hydrolyzed acrylate monomer and an initiator I to obtain the polyacrylamide aqueous dispersion; wherein the stabilizer is a cationic copolymer of a polyacrylamide segment.

[0007] According to some embodiments of the present application, the mass ratio of the acrylamide I, the cationic monomer I, the inorganic salt, the easily hydrolyzed acrylate monomer and the stabilizer is 36:4.32; 10:(1-2):270, preferably 36:4.32; 10:1.5:270.

[0008] According to some embodiments of the present application, the amount of the initiator I added is 0.1%-0.5% of the mass of the acrylamide I.

[0009] According to some embodiments of the present application, the cationic monomer I is selected from one or more of acryloyloxyethyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride, dimethyldiallyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride, 2-acrylamido-2-methylpropyl trimethyl ammonium chloride.

[0010] According to some embodiments of the present application, the inorganic salt is selected from ammonium salt; preferably, the ammonium salt is selected from at least one of ammonium sulfate, ammonium persulfate.

[0011] According to some embodiments of the present application, the initiator I is selected from aqueous thermal initiator I and / or redox initiator I; preferably, the aqueous thermal initiator I is selected from at least one of V-50, VA-044; the redox initiator I is selected from at least two of ammonium persulfate, sodium bisulfite, potassium persulfate.

[0012] According to some embodiments of the present application, the easily hydrolyzed acrylate monomer is selected from at least one of tert-butyl acrylate, tert-butyl methacrylate, phenyl acrylate, phenyl methacrylate.

[0013] According to some embodiments of the present application, the reaction I is carried out under the conditions of temperature 25-45℃ and time 1-6 hours.

[0014] According to some embodiments of the present application, the preparation of the stabilizer comprises mixing the cationic monomer II, the acrylamide II in water under the conditions of initiator II and non-active atmosphere to obtain a mixed solution, and reaction II to obtain the stabilizer.

[0015] According to some embodiments of the present application, the mass ratio of the cationic monomer II, the acrylamide II and water is (40-90):(60-84):160, preferably 72:60:160, 48:84:160.

[0016] According to some embodiments of the present application, the amount of the initiator II added is 0.1%-0.5% of the mass of the cationic monomer II.

[0017] According to some embodiments of the present application, the cationic monomer II is selected from one or more of acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, dimethyldiallylammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, methacryloyloxyethyldimethylbenzylammonium chloride, 2-acrylamido-2-methylpropyltrimethylammonium chloride.

[0018] According to some embodiments of the present application, the initiator II is selected from an aqueous thermal initiator II and / or a redox initiator II; preferably, the aqueous thermal initiator II is selected from at least one of V-50, VA-044; the redox initiator II is selected from at least two of ammonium persulfate, sodium bisulfite, potassium persulfate.

[0019] According to some embodiments of the present application, the non-living atmosphere is selected from at least one of nitrogen, argon.

[0020] According to some embodiments of the present application, the reaction II is performed at a temperature of 30-80°C for 5-10 hours.

[0021] According to some embodiments of the present application, the reaction II is followed by dilution; preferably, the stabilizer is cooled to room temperature, and then a certain amount of water is added to dilute the stabilizer to a mass concentration of 5-10 wt%, to obtain an aqueous solution of the cationic copolymer containing polyacrylamide segments.

[0022] The second aspect of the present application provides a polyacrylamide aqueous dispersion obtained by the above method for synthesizing a polyacrylamide aqueous dispersion.

[0023] The third aspect of the present application provides an application of the above polyacrylamide aqueous dispersion as a flocculant in sewage and / or wastewater treatment.

[0024] Advantages:

[0025] The polyacrylamide aqueous dispersion prepared by the present application has a low apparent viscosity, and is thus convenient to use.

[0026] The polyacrylamide aqueous dispersion prepared by the present application has good stability, and no destabilization occurs when it is placed at room temperature for 6 months.

[0027] The polyacrylamide aqueous dispersion prepared by the present application can be widely applied as a flocculant in the environmental protection field, such as sewage and wastewater treatment in the petroleum chemical industry, printing, steelmaking, and papermaking industry. DETAILED DESCRIPTION

[0028] The present application will be further described below in conjunction with examples. However, the present application is not limited by these examples.

[0029] Unless otherwise specified, the three-necked flasks and three-necked bottles used in the examples of the present invention are common commercially available products.

[0030] Methacryloxyethyltrimethylammonium chloride, acrylamide, phenyl acrylate, tert-butyl acrylate, VA-044 initiator, ammonium sulfate, ammonium persulfate, and sodium bisulfite in the present invention are all common commercially available reagents unless otherwise specified.

[0031] Unless otherwise specified, the room temperature in the embodiments of the present invention is 25°C.

[0032] Example 1

[0033] This embodiment provides a cationic copolymer.

[0034] In a three-necked flask, 90 g of an 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride, 60 g of acrylamide, 0.10 g of VA-044 initiator, and 160 g of water were added in sequence. After degassing and deoxygenation, nitrogen was introduced and the mixture was reacted at 45°C for 7 hours. The mixture was then cooled to room temperature and diluted with 2330 g of water to a 5% aqueous solution containing the cationic copolymer, namely, Stabilizer A1.

[0035] Example 2

[0036] This embodiment provides a cationic copolymer.

[0037] To a three-necked flask were added, in sequence, 60 g of an 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride, 84 g of acrylamide, 0.10 g of VA-044 initiator, and 160 g of water. After degassing and deoxygenation, the mixture was filled with nitrogen and allowed to react at 45°C for 7 hours. The mixture was then cooled to room temperature and diluted with 2330 g of water to a 5% aqueous solution containing a cationic copolymer, namely, Stabilizer A2.

[0038] Example 3

[0039] This embodiment provides an aqueous dispersion of polyacrylamide.

[0040] At room temperature, 36 g of acrylamide, 5.4 g of an 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride, 1.5 g of phenyl acrylate, 270 g of the above-mentioned stabilizer A1 (a 5% aqueous solution containing a cationic copolymer) and 10 g of ammonium sulfate were added to a three-necked flask equipped with a stirring paddle. The mixture was stirred until all the added materials were completely dissolved. The mixture was then degassed and deoxygenated, and nitrogen was introduced. The temperature was raised to 45° C., and 1 mL of a degassed and deoxygenated aqueous solution of VA-044 (the concentration of the VA-044 aqueous solution was 40 mg / mL) was added. The reaction was continued for 6 hours, and the heating source was removed to stop the reaction to obtain an aqueous polyacrylamide dispersion B1.

[0041] Example 4

[0042] This embodiment provides an aqueous dispersion of polyacrylamide.

[0043] At room temperature, 36 g of acrylamide, 5.4 g of an 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride, 1.5 g of phenyl acrylate, 270 g of the stabilizer A1 (a 5% aqueous solution containing a cationic copolymer) and 10 g of ammonium sulfate were added to a three-necked flask equipped with a stirring paddle. The mixture was stirred until all the added materials were completely dissolved. The mixture was then degassed and deoxygenated, and nitrogen was introduced. The temperature was raised to 30° C., and 0.60 mL of a degassed and deoxygenated aqueous solution of ammonium persulfate (the concentration of the aqueous solution of ammonium persulfate was 40 mg / mL) and 0.40 mL of an aqueous solution of sodium bisulfite (the concentration of the aqueous solution of sodium bisulfite was 40 mg / mL) were respectively added. The reaction was continued for 6 hours, and the heating source was removed to terminate the reaction to obtain an aqueous polyacrylamide dispersion B2.

[0044] Example 5

[0045] This embodiment provides an aqueous dispersion of polyacrylamide.

[0046] At room temperature, 36 g of acrylamide, 5.4 g of an 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride, 1.5 g of tert-butyl acrylate, 270 g of the above-mentioned stabilizer A2 (a 5% aqueous solution containing a cationic copolymer) and 10 g of ammonium sulfate were added to a three-necked flask equipped with a stirring paddle. The mixture was stirred until all the added materials were completely dissolved. The mixture was then degassed and deoxygenated, and nitrogen was introduced. The temperature was raised to 45° C., and 1 mL of a degassed and deoxygenated aqueous solution of VA-044 (the concentration of the VA-044 aqueous solution was 40 mg / mL) was added. The reaction was continued for 6 hours, and the heating source was removed to stop the reaction to obtain an aqueous polyacrylamide dispersion B3.

[0047] Comparative Example 1

[0048] This comparative example provides an aqueous dispersion of polyacrylamide.

[0049] At room temperature, 36 g of acrylamide, 5.4 g of an 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride, 270 g of stabilizer A1 (a 5% aqueous solution of a cationic copolymer) and 10 g of ammonium sulfate were added to a three-necked flask equipped with a stirring paddle. The mixture was stirred until all the added materials were completely dissolved. The mixture was then degassed and deoxygenated, and nitrogen was introduced. The temperature was raised to 45° C., and 1 mL of a degassed and deoxygenated aqueous solution of VA-044 (the concentration of the VA-044 aqueous solution was 40 mg / mL) was added. The reaction was continued for 6 hours, and the heating source was removed to stop the reaction to obtain an aqueous polyacrylamide dispersion B4.

[0050] Comparative Example 2

[0051] The present comparative example provides a polyacrylamide aqueous dispersion.

[0052] Into a three-necked flask equipped with a stirring paddle, 36 g of acrylamide, 5.4 g of a 80% by mass aqueous solution of methacryloyloxyethyltrimethylammonium chloride, 270 g of stabilizer A1 (a 5% by mass aqueous solution of a cationic copolymer) and 10 g of ammonium sulfate were added at room temperature, and stirred until all the added substances were completely dissolved. After degassing and oxygen removal, nitrogen was filled, and the temperature was raised to 30°C. 0.60 mL of a degassed and oxygen-removed aqueous solution of ammonium persulfate (40 mg / mL) and 0.40 mL of a degassed and oxygen-removed aqueous solution of sodium bisulfite (40 mg / mL) were added, respectively, and the reaction was continued for 6 hours. The heating source was removed, and the reaction was stopped to obtain a polyacrylamide aqueous dispersion B5.

[0053] Test Example

[0054] (I) Stabilizer parameters

[0055] The basic parameters of the stabilizers A1-A2 prepared in Examples 1-2 of the present application are shown in Table 1.

[0056] In Table 1, the appearance, solid content and viscosity of the stabilizers A1-A2 were tested in accordance with GB / T 11175-2002.

[0057] The viscosity testing instrument was a Brookfield viscometer DV1, and the viscosity determination method was to directly test at a temperature of 25°C.

[0058] Comparison of the basic parameters of the stabilizers prepared in Examples 1-2 of the present application

[0059]

[0060] (II) Polyacrylamide aqueous dispersion parameters

[0061] The basic parameters of the polyacrylamide aqueous dispersions prepared in Examples 3-5 and Comparative Examples 1-2 of the present application are shown in Table 2.

[0062] The polymer concentration measurement method was as follows: a weight C1 of the polyacrylamide aqueous dispersion was diluted with water to a concentration of 1%, and was placed in a dialysis bag (molecular weight cut-off size: 1000 D) for dialysis in water for three days. Then, the sample was freeze-dried to obtain a dry sample weight C2, and the polymer concentration was the percentage of the ratio of C2 and CI.

[0063] wherein the apparent viscosity is the viscosity of the polyacrylamide aqueous dispersion prepared in Examples 3-5 and Comparative Examples 1-2 without dilution with water; and the viscosity of a 1% polymer solution is the viscosity of a solution of the polyacrylamide aqueous dispersion diluted with water to a concentration of 1% by mass of the polyacrylamide and copolymer thereof.

[0064] wherein the stability of the polyacrylamide aqueous dispersion prepared in Examples 3-5 and Comparative Examples 1-2 of the present application at room temperature is observed by eye, and the dispersion is stable if it does not separate into layers, and unstable if it separates into layers.

[0065] Table 2 Parameters of the polyacrylamide aqueous dispersion prepared in Examples 3-5 and Comparative Examples 1-2 of the present application

[0066]

[0067] The results in Table 2 show that the polyacrylamide aqueous dispersion prepared in Examples 3-5 has a lower apparent viscosity and a higher viscosity of a 1% polymer solution, and a stability of more than 6 months. The polyacrylamide aqueous dispersion prepared in Comparative Examples 1 and 2 has a higher apparent viscosity, but a stability of only 3 months and 1 month. This shows that the polyacrylamide aqueous dispersion prepared in the present application has a lower apparent viscosity.

[0068] It should be noted that the above-described examples are merely intended to explain the present application, and do not constitute any limitation on the present application. The present application has been described by referring to typical examples, but it should be understood that the words used therein are descriptive and explanatory words, and are not limiting words. The present application can be modified within the scope of the claims, and can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and examples, it does not mean that the present application is limited to the specific examples disclosed therein, but rather, the present application can be extended to all other methods and applications having the same function.

Claims

1. A method for synthesizing an aqueous polyacrylamide dispersion, characterized in that: The method comprises subjecting a reaction system of acrylamide I, a cationic monomer I, an inorganic salt, a stabilizer, a readily hydrolyzable acrylate monomer, and an initiator I to a reaction I to obtain the polyacrylamide aqueous dispersion; wherein the stabilizer is an aqueous solution of a cationic copolymer containing polyacrylamide segments at a mass concentration of 5 wt% to 10 wt%; The easily hydrolyzed acrylic acid ester monomer is selected from at least one of tert-butyl acrylate, tert-butyl methacrylate, phenyl acrylate, and phenyl methacrylate; The mass ratio of the acrylamide I, cationic monomer I, inorganic salt, easily hydrolyzed acrylic ester monomer and stabilizer is 36:4.32:10:(1-2):270; The added amount of the initiator I is 0.1% to 0.5% of the mass of the acrylamide I.

2. The synthesis method according to claim 1, wherein The mass ratio of the acrylamide I, the cationic monomer I, the inorganic salt, the easily hydrolyzed acrylic ester monomer and the stabilizer is 36:4.32:10:1.5:

270.

3. The synthesis method according to claim 1, wherein The cationic monomer I is selected from one or more of acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, dimethyldiallyl ammonium chloride, acryloyloxyethyldimethylbenzyl ammonium chloride, methacryloyloxyethyldimethylbenzyl ammonium chloride, and 2-acrylamido-2-methylpropyltrimethylammonium chloride; and / or, the inorganic salt is selected from ammonium salts; And / or, the initiator I is selected from aqueous thermal initiator I and / or redox initiator I.

4. The synthesis method according to claim 3, characterized in that The ammonium salt is selected from ammonium sulfate; And / or, the aqueous thermal initiator I is selected from at least one of V-50 and VA-044; the redox initiator I is selected from at least two of ammonium persulfate, sodium bisulfite, and potassium persulfate.

5. The synthesis method according to any one of claims 1 to 4, characterized in that The conditions of the reaction I include: a temperature of 25° C. to 45° C., and a time of 1 hour to 6 hours.

6. The synthesis method according to any one of claims 1 to 4, characterized in that The preparation of the stabilizer comprises: mixing a cationic monomer II and acrylamide II in water in the presence of an initiator II and an inactive atmosphere, and performing a reaction II to obtain the stabilizer.

7. The synthesis method according to claim 6, characterized in that The mass ratio of the cationic monomer II, acrylamide II and water is (40-90): (60-84): 160; And / or, the added amount of the initiator II is 0.1% to 0.5% of the mass of the cationic monomer II.

8. The synthesis method according to claim 6, characterized in that The cationic monomer II is selected from one or more of acryloyloxyethyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride, and 2-acrylamido-2-methylpropyl trimethyl ammonium chloride; and / or, the initiator II is selected from aqueous thermal initiator II and / or redox initiator II; And / or, the inactive atmosphere is selected from at least one of nitrogen and argon.

9. The synthesis method according to claim 8, characterized in that The aqueous thermal initiator II is selected from at least one of V-50 and VA-044; the redox initiator II is selected from at least two of ammonium persulfate, sodium bisulfite, and potassium persulfate.

10. The synthesis method according to claim 6, characterized in that The conditions of the reaction II include: a temperature of 30°C to 80°C, and a reaction time of 5 hours to 10 hours; And / or, the reaction II further includes dilution.

11. An aqueous dispersion of polyacrylamide obtained by the synthesis method according to any one of claims 1 to 10.

12. Use of the polyacrylamide aqueous dispersion obtained by the synthesis method according to any one of claims 1 to 10 or the polyacrylamide aqueous dispersion according to claim 11 as a flocculant in sewage and / or wastewater treatment.

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