Macromolecular surfactant as well as preparation method and application thereof

Abstract

The invention relates to a surfactant, in particular to a macromolecular surfactant as well as a preparation method and application thereof. In the current situation that a micromolecular surfactant is usually used as a formula emulsifier, the invention prepares a macromolecular surfactant which can achieve an emulsification stabilizing effect when being independently used. The macromolecular surfactant disclosed by the invention is a cross-linked polymer generated by reacting modified alginate, polyacrylamide, tetramethylethylenediamine and N, N '-methylene bisacrylamide in an emulsifier aqueous solution. The macromolecular surfactant prepared by the invention is low in critical micelle concentration, and has high emulsion stabilization efficiency at very low concentration; the emulsion can be used as an emulsifier or a stabilizer of a water-in-oil (W / O) emulsion and a water-in-oil-in-water (W / O / W) emulsion.

Description

TECHNICAL FIELD

[0001] The present application relates to a surfactant, and further relates to a macromolecular surfactant and a preparation method and application thereof. BACKGROUND

[0002] A surfactant, also known as an interfacial active agent, is a compound capable of significantly reducing the surface tension or interfacial tension between two liquids, liquid-gas, or liquid-solid. Surfactants can reduce the flow resistance of a liquid and save energy, and thus play an important role in the field of fluid transportation and distribution.

[0003] Small molecule surfactants are usually used as emulsifiers in water-in-oil emulsions, oil-in-water emulsions, and high internal phase emulsions (HIPEs). To form a stable emulsion, a small molecule surfactant is usually required as a formula emulsifier (the small molecule surfactant needs to be used in combination with other emulsifiers).

[0004] In addition, to form a stable emulsion, a large amount of relatively expensive small molecule surfactants are usually required. The large amount of small molecule surfactants used makes it easy for the small molecule surfactants to be left behind. The small molecule surfactants left behind in the polymer structure act as plasticizers when the polymer is dried, which can plasticize the polymer foam, resulting in shrinkage of the polymer, deformation of the polymer pores, and poor mechanical properties. At the same time, there are problems such as inhibition of coalescence, emulsification, flocculation, and deposition of the oil and water phases. SUMMARY

[0005] In view of the current situation that small molecule surfactants are usually used as formula emulsifiers, the present application uses modified alginate and polyacrylamide as main raw materials to prepare a macromolecular surfactant that does not need to be used as a formula emulsifier and can achieve emulsification and stabilization effects when used alone. The macromolecular surfactant prepared by the present application has a low critical micelle concentration and high emulsion stabilization efficiency at very low concentrations.

[0006] One of the objects of the present application is to provide a macromolecular surfactant.

[0007] The second object of the present application is to provide a preparation method of the macromolecular surfactant according to the first object.

[0008] The third object of the present application is to provide an application of the macromolecular surfactant according to the first object.

[0009] The macromolecular surfactant is prepared by reacting modified alginate, polyacrylamide, tetramethyl ethylenediamine and N,N'-methylene bisacrylamide in an emulsifier aqueous solution. The macromolecular surfactant is a mixture containing a cross-linked polymer generated by the reaction and raw materials not participating in the reaction.

[0010] The modified alginate is obtained by partially protonating alginate with an acid to obtain partially protonated alginate, and then performing esterification reaction of the partially protonated alginate with a fatty alcohol.

[0011] The acid is selected from one or more of concentrated sulfuric acid, methanesulfonic acid, benzenesulfonic acid and p-toluenesulfonic acid.

[0012] The fatty alcohol is selected from one or more of octanol, dodecanol, hexadecanol and cholesterols.

[0013] The mass ratio of the alginate to the acid is 1-10:1, preferably 1-5:1.

[0014] The mass ratio of the alginate to the fatty alcohol is 1-5:10, preferably 2-5:10.

[0015] The modification method of the modified alginate is a conventional method. Specifically, the modified alginate is prepared by the following method:

[0016] (1) dissolving alginate and acid in an organic solvent and stirring at room temperature; the stirring time can be 5-50 min, preferably 10-30 min; during the stirring, the acid partially protonates the -COO- of the alginate into -COOH to obtain partially protonated alginate; the protonation degree of the partially protonated alginate is 20-40%; the protonation degree is defined as the molar percentage of carboxyl-containing uronic acid units in the total uronic acid units in the alginate; the alginate can be any conventional alginate, specifically, commercially available alginate with a weight average relative molecular weight of 300-400,000; the acid is selected from one or more of concentrated sulfuric acid, methanesulfonic acid, benzenesulfonic acid and p-toluenesulfonic acid; the organic solvent is selected from one or more of N,N-dimethylformamide, formamide and dimethyl sulfoxide; when the organic solvent is N,N-dimethylformamide, the mass ratio of the alginate to N,N-dimethylformamide is 1:30-50, preferably 1:30-40;

[0017] (2) at room temperature, adding a fatty alcohol and a catalyst to the product of step (1) and stirring to obtain an esterification mixture; the stirring time is 2-10 h, preferably 3-6 h; during the stirring, the -COOH of the partially protonated alginate reacts with the hydroxyl of the fatty alcohol to form an alginate esterification product; the alginate esterification product is the modified alginate; the fatty alcohol is selected from one or more of octanol, dodecanol, cetyl alcohol, and cholesterols; the catalyst is selected from one or more of 4-dimethylaminopyridine, 4-pyrrolidinopyridine, N,N-dicyclohexyl carbodiimide, 5,6,9,10-tetrahydro-4H,8H-pyrido[3,2,1-ij][1,6]naphthyridine (CAS: 6052-72-8), and pyridine; when the catalyst is 4-dimethylaminopyridine and the fatty alcohol is dodecanol, the mass ratio of 4-dimethylaminopyridine to dodecanol is 1:10-30; preferably 1:10-15; the esterification mixture contains the alginate esterification product, the catalyst, the organic solvent, and unreacted raw materials;

[0018] (3) washing the esterification mixture, centrifuging to separate the precipitate, removing the catalyst, the organic solvent, and unreacted raw materials from the esterification mixture, dissolving the lower layer (alginate esterification product) in distilled water, and freeze-drying to obtain the modified alginate; preferably, the esterification mixture is washed with ethanol.

[0019] The relatively low amphiphilicity of alginate is not conducive to the adsorption stability of its molecular chain at the interface, and therefore, the alginate is appropriately hydrophobically modified to enhance its amphiphilicity, so that it can more stably form an interface adsorption. In the present application, the -COO- of the alginate is first protonated into -COOH by using an acid to obtain a partially protonated alginate, and then a long-chain hydrophobic group (a fatty alcohol such as dodecanol) is grafted onto the molecular chain of the partially protonated alginate through an esterification reaction to obtain a modified alginate with stronger hydrophobicity.

[0020] The present application further enables the modified alginate with strong hydrophobicity to cross-link with the polyacrylamide with strong hydrophilicity in an emulsifier aqueous solution to form a cross-linked polymer; the obtained cross-linked polymer has amphiphilicity, and has strong hydrophilicity and lipophilicity; and thus a macromolecular surfactant with strong hydrophilicity and lipophilicity is obtained.

[0021] The macromolecular surfactant obtained in the present application exhibits a very low critical micelle concentration (CMC range of 10 -9 ~10 -4The macromolecular surfactant has the advantages that the critical micelle concentration is low, the emulsion can be stabilized at a small dosage, the macromolecular surfactant has good mechanical properties and wide functionality, and the macromolecular surfactant is a macromolecular surfactant with excellent performance.

[0022] The preparation method of the second invention purpose comprises the following steps:

[0023] (1) mixing the emulsifier with water to obtain an emulsifier aqueous solution;

[0024] (2) adding the modified alginate and the polyacrylamide to the emulsifier aqueous solution, and mixing the modified alginate and the polyacrylamide to obtain a mixed solution;

[0025] (3) adding tetramethyl ethylenediamine and N,N'-methylene bisacrylamide to the mixed solution to obtain a reaction system, and performing cross-linking reaction on the reaction system under vacuum, and obtaining a mixture containing a cross-linked polymer after the cross-linking reaction, wherein the mixture containing the cross-linked polymer is the crude macromolecular surfactant.

[0026] Further, the preparation method comprises the following steps:

[0027] (4) after the crude macromolecular surfactant is cooled to room temperature, the crude macromolecular surfactant is crushed and dried to obtain a powdery macromolecular surfactant.

[0028] The modified alginate is at least one of modified sodium alginate and modified potassium alginate. That is, the modified alginate can be modified sodium alginate, modified potassium alginate, or a combination of modified sodium alginate and modified potassium alginate. The modified sodium alginate is preferably selected.

[0029] The polyacrylamide can be any molecular weight and any structure of polyacrylamide available on the market. The polyacrylamide is a hydrophilic polymer material without a hydrophobic group (oleophilic group) and cannot be used as an emulsifier alone because it does not have an amphiphilic structure of a surfactant.

[0030] The preparation method of the present application is to cross-link the modified alginate and the polyacrylamide as main reactants. The two polymers are cross-linked to form a polymer structure with regular steps and simpler procedures.

[0031] The cross-linking reaction of the modified alginate and the polyacrylamide in the preparation method is carried out in the emulsifier aqueous solution. The hydrophobicity of the modified alginate is enhanced, and the emulsifier aqueous solution plays a role of solubilization. The emulsifier aqueous solution has a certain viscosity, and can make the cross-linking reaction more easily carried out. The emulsifier is selected from at least one of octylphenyl polyoxyethylene ether, isomeric decanol polyoxyethylene ether and castor oil polyoxyethylene ether.

[0032] It is found through experiments that the solubility of octylphenyl polyoxyethylene ether (for example, TX-100) is fast (specifically, the solubility of the modified alginate is improved, the hydrophilicity of the alginate is poor after being hydrophobically modified, and the emulsifier can improve the solubility), and the viscosity of the mixed solution is higher, so that the solubility of the macromolecular surfactant prepared is better; therefore, the octylphenyl polyoxyethylene ether (for example, TX-100) is more preferably selected as the emulsifier.

[0033] In step (1), the content of the emulsifier in the emulsifier aqueous solution is 1-1.5wt%, and is preferably 1-1.2wt%.

[0034] In step (2), the total amount of the modified alginate and the polyacrylamide is 0.15-0.3g / mL, and is preferably 0.2-0.3g / mL, relative to the amount of the emulsifier aqueous solution.

[0035] In step (2), the molar ratio of the modified alginate to the polyacrylamide is 1:1.5-4, and is preferably 1:1.5-2.5.

[0036] Among them, relative to the macromolecular surfactant with a molar ratio of the modified alginate to the polyacrylamide of 1:4, the macromolecular surfactant with a molar ratio of the modified alginate to the polyacrylamide of 1:1.5-2.5 has a lower CMC, a higher emulsion viscosity, a smaller emulsion D50 particle size and a better stability. Therefore, as a preferred scheme, the molar ratio of the modified alginate to the polyacrylamide is 1:1.5-2.5.

[0037] In step (3), the content of tetramethylethylenediamine in the reaction system is 0.04-0.1wt%, and is preferably 0.04-0.09wt%; the content of N,N'-methylenebisacrylamide is 0.4-0.6wt%, and is preferably 0.4-0.5wt%.

[0038] In step (3), the cross-linking reaction temperature is 30-80℃, and is preferably 40-70℃; the cross-linking reaction time is 30-80min, and is preferably 40-50min.

[0039] The preparation method of the present application, a specific scheme, comprises:

[0040] (1) TX-100 is dissolved in water to prepare a TX-100 aqueous solution with a concentration of 1-1.5 wt%, preferably 1-1.2 wt%;

[0041] (2) modified sodium alginate and polyacrylamide are dissolved in the TX-100 aqueous solution prepared in step (1) to obtain a mixture; wherein the total amount of modified sodium alginate and polyacrylamide is 1.5-3 g to 10 mL of the TX-100 aqueous solution, preferably 2-3 g to 10 mL of the TX-100 aqueous solution; the molar ratio of modified sodium alginate to polyacrylamide is (2:8)-(4:6), preferably (3:7)-(4:6);

[0042] (3) tetramethyl ethylenediamine and N,N'-methylene bisacrylamide are added to the mixture and stirred until completely dissolved to obtain a reaction system; in the reaction system, the content of tetramethyl ethylenediamine is 0.04-0.1 wt%, preferably 0.04-0.09 wt%; the content of N,N'-methylene bisacrylamide is 0.4-0.6 wt%, preferably 0.4-0.5 wt%;

[0043] (4) the reaction system is subjected to crosslinking reaction in a vacuum drying box; the crosslinking reaction temperature is 30-80℃, preferably 40-70℃; the crosslinking reaction time is 30-80 min, preferably 40-50 min;

[0044] (5) after the crosslinking reaction is completed, the reaction system is cooled to room temperature, crushed and dried to obtain a powdered macromolecular surfactant.

[0045] The application of the third object of the application refers to the application of the macromolecular surfactant of the first object of the application in water-in-oil (W / O) emulsion and water-in-oil-in-water (W / O / W) emulsion. Specifically, the macromolecular surfactant is used as an emulsifier or stabilizer of water-in-oil (W / O) emulsion and water-in-oil-in-water (W / O / W) emulsion.

[0046] Compared with the prior art, the application has the following beneficial effects:

[0047] The macromolecular surfactant prepared by the application can form a relatively stable adsorption layer on the oil-water interface during the oil-water emulsification process, preventing the aggregation of droplets (improving the aggregation stability) and being conducive to improving the stability of the emulsion system.

[0048] The macromolecular surfactant prepared by the application has a low CMC value, can greatly reduce the dosage, and can produce emulsions with high stability under a small amount of dosage. In addition, the dosage is small and the concentration is low, and there is no residual problem.

[0049] The macromolecular surfactant prepared by the method is an environment-friendly emulsifier, and has the characteristics of biodegradability and low price.

[0050] The emulsion prepared by the macromolecular surfactant has certain shear resistance, high viscosity, small particle size and strong stability.

[0051] The preparation method has mild preparation conditions. DETAILED DESCRIPTION

[0052] It is necessary to point out that the following examples are only used to further illustrate the present application, and cannot be understood as limiting the protection scope of the present application, and some non-essential improvements and adjustments of the present application made by those skilled in the art according to the content of the present application still belong to the protection scope of the present application.

[0053] The raw materials used in the following examples and comparative examples are all commercially available products, and the manufacturers are shown in Table 1.

[0054] Table 1

[0055] Raw materials Manufacturers Production specifications TX-100 Meryer AR Sodium alginate Meryer AR 4-dimethylaminopyridine Meryer AR p-toluenesulfonic acid Meryer AR Dodecanol Meryer AR Polyacrylamide Araldine Company AR N,N'-methylene bisacrylamide Araldine Company AR Tetramethyl ethylenediamine Araldine Company AR Ammonium persulfate Merck Company AR Anhydrous calcium chloride Merck Company AR Sodium dodecylbenzenesulfonate Shandong Yongsheng Chemical Co., Ltd. Dodecyl trimethyl ammonium chloride Jinan Ronghao Chemical Co., Ltd.

[0056] Example 1

[0057] (1) 10 g of sodium alginate, 5 g of p-toluenesulfonic acid were dissolved in 330 g of N, N-dimethylformamide (solvent), and stirred at room temperature for 20 min; 5 g of 4-dimethylaminopyridine (catalyst) and 50 g of dodecanol were added at room temperature, and stirred for 5 h to obtain a reaction mixture; the reaction mixture was washed with ethanol, and the precipitated product was centrifuged, dissolved in distilled water, and freeze-dried to obtain a pure product, modified sodium alginate;

[0058] (2) The emulsifier TX-100 was dissolved in water to prepare a 1.2 wt% TX-100 aqueous solution;

[0059] (3) The modified sodium alginate and polyacrylamide were dissolved in 10 mL of the TX-100 aqueous solution prepared in step (1); after the mixture of the modified sodium alginate and the polyacrylamide was fully dissolved, tetramethyl ethylenediamine and N, N'-methylene bisacrylamide were added, and mechanical stirring was carried out at 500 r / min for 10 min to obtain a reaction system; wherein the total amount of the modified sodium alginate and the polyacrylamide was 3 g, and the molar ratio of the modified sodium alginate to the polyacrylamide was 38:62; in the reaction system, the content of tetramethyl ethylenediamine was 0.04 wt%, and the content of N, N'-methylene bisacrylamide was 0.4 wt%;

[0060] (4) The reaction system is transferred to a flask, and the flask is placed in a vacuum drying box at 60°C for 40 min to obtain a mixture containing crosslinked polymers; the mixture containing crosslinked polymers is the crude macromolecular surfactant;

[0061] (5) After the mixture containing crosslinked polymers is cooled to room temperature, it is crushed and dried to obtain a powdery macromolecular surfactant.

[0062] Example 2

[0063] (1) Dissolve the emulsifier TX-100 in water to prepare a 1.1wt% TX-100 aqueous solution;

[0064] (2) Dissolve the modified sodium alginate and polyacrylamide prepared in Example 1 in 10 mL of the TX-100 aqueous solution prepared in step (1); after the mixture of modified sodium alginate and polyacrylamide is fully dissolved, tetramethyl ethylenediamine and N,N'-methylene bisacrylamide are added, and mechanical stirring is performed at 500 r / min for 10 min to obtain a reaction system; wherein the total amount of modified sodium alginate and polyacrylamide is 3 g, and the molar ratio of modified sodium alginate to polyacrylamide is 36:64; in the reaction system, the content of tetramethyl ethylenediamine is 0.06wt%, and the content of N,N'-methylene bisacrylamide is 0.5wt%;

[0065] (3) The reaction system is transferred to a flask, and the flask is placed in a vacuum drying box at 60°C for 50 min to obtain a mixture containing crosslinked polymers; the mixture containing crosslinked polymers is the crude macromolecular surfactant;

[0066] (4) After the mixture containing crosslinked polymers is cooled to room temperature, it is crushed and dried to obtain a powdery macromolecular surfactant.

[0067] Example 3

[0068] (1) Dissolve the emulsifier TX-100 in water to prepare a 1.0wt% TX-100 aqueous solution;

[0069] (2) Dissolve the modified sodium alginate and polyacrylamide prepared in Example 1 in 10 mL of the TX-100 aqueous solution prepared in step (1); after the mixture of modified sodium alginate and polyacrylamide is fully dissolved, tetramethyl ethylenediamine and N,N'-methylene bisacrylamide are added, and mechanical stirring is performed at 500 r / min for 10 min to obtain a reaction system; wherein the total amount of modified sodium alginate and polyacrylamide is 3 g, and the molar ratio of modified sodium alginate to polyacrylamide is 35:65; in the reaction system, the content of tetramethyl ethylenediamine is 0.07wt%, and the content of N,N'-methylene bisacrylamide is 0.4wt%;

[0070] (3) The reaction system is transferred to a flask, and the flask is placed in a 60°C vacuum drying oven for 40 minutes to obtain a mixture containing crosslinked polymers; the mixture containing crosslinked polymers is the crude macromolecular surfactant;

[0071] (4) After the mixture containing crosslinked polymers is cooled to room temperature, it is crushed and dried to obtain a powdery macromolecular surfactant.

[0072] Example 4

[0073] (1) Dissolve the emulsifier TX-100 in water to prepare a 1.0wt% TX-100 aqueous solution;

[0074] (2) Dissolve the modified sodium alginate and polyacrylamide prepared in Example 1 in 10 mL of the TX-100 aqueous solution prepared in step (1); after the mixture of modified sodium alginate and polyacrylamide is fully dissolved, tetramethyl ethylenediamine and N,N'-methylene bisacrylamide are added, and mechanical stirring is performed at 500 r / min for 10 minutes to obtain a reaction system; wherein the total amount of modified sodium alginate and polyacrylamide is 2 g, and the molar ratio of modified sodium alginate to polyacrylamide is 32:68; in the reaction system, the content of tetramethyl ethylenediamine is 0.04wt%, and the content of N,N'-methylene bisacrylamide is 0.4wt%;

[0075] (3) The reaction system is transferred to a flask, and the flask is placed in a 60°C vacuum drying oven for 40 minutes to obtain a mixture containing crosslinked polymers; the mixture containing crosslinked polymers is the crude macromolecular surfactant;

[0076] (4) After the mixture containing crosslinked polymers is cooled to room temperature, it is crushed and dried to obtain a powdery macromolecular surfactant.

[0077] Example 5

[0078] (1) Dissolve the emulsifier TX-100 in water to prepare a 1.0wt% TX-100 aqueous solution;

[0079] (2) Dissolve the modified sodium alginate and polyacrylamide prepared in Example 1 in 10 mL of the TX-100 aqueous solution prepared in step (1); after the mixture of modified sodium alginate and polyacrylamide is fully dissolved, tetramethyl ethylenediamine and N,N'-methylene bisacrylamide are added, and mechanical stirring is performed at 500 r / min for 10 minutes to obtain a reaction system; wherein the total amount of modified sodium alginate and polyacrylamide is 2 g, and the molar ratio of modified sodium alginate to polyacrylamide is 32:68; in the reaction system, the content of tetramethyl ethylenediamine is 0.04wt%, and the content of N,N'-methylene bisacrylamide is 0.4wt%;

[0080] (3) The reaction system was transferred to a flask, the flask was placed in a 40℃ vacuum drying oven for 50min, and a mixture containing crosslinked polymers was obtained; the mixture containing crosslinked polymers was the crude macromolecular surfactant;

[0081] (4) After the mixture containing crosslinked polymers was cooled to room temperature, it was crushed and dried to obtain a powdery macromolecular surfactant.

[0082] Example 6

[0083] (1) The emulsifier TX-100 was dissolved in water to prepare a 1.0wt% TX-100 aqueous solution;

[0084] (2) The modified sodium alginate and polyacrylamide prepared in Example 1 were dissolved in 10mL of the TX-100 aqueous solution prepared in step (1); after the mixture of modified sodium alginate and polyacrylamide was fully dissolved, tetramethyl ethylenediamine and N,N'-methylene bisacrylamide were added, and mechanical stirring was performed at 500r / min for 10min to obtain a reaction system; wherein the total amount of modified sodium alginate and polyacrylamide was 1.5g, and the molar ratio of modified sodium alginate to polyacrylamide was 20:80; in the reaction system, the content of tetramethyl ethylenediamine was 0.04wt%, and the content of N,N'-methylene bisacrylamide was 0.4wt%;

[0085] (3) The reaction system was transferred to a flask, the flask was placed in a 40℃ vacuum drying oven for 50min, and a mixture containing crosslinked polymers was obtained; the mixture containing crosslinked polymers was the crude macromolecular surfactant;

[0086] (4) After the mixture containing crosslinked polymers was cooled to room temperature, it was crushed and dried to obtain a powdery macromolecular surfactant.

[0087] Comparative Example 1

[0088] (1) The emulsifier TX-100 was dissolved in water to prepare a 1.0wt% TX-100 aqueous solution;

[0089] (2) The modified sodium alginate and polyacrylamide prepared in Example 1 were dissolved in 10mL of the TX-100 aqueous solution prepared in step (1); after the mixture of modified sodium alginate and polyacrylamide was fully dissolved, tetramethyl ethylenediamine and N,N'-methylene bisacrylamide were added, and mechanical stirring was performed at 500r / min for 10min to obtain a reaction system; wherein the total amount of modified sodium alginate and polyacrylamide was 1g, and the molar ratio of modified sodium alginate to polyacrylamide was 10:90; in the reaction system, the content of tetramethyl ethylenediamine was 0.04wt%, and the content of N,N'-methylene bisacrylamide was 0.4wt%;

[0090] (3) The reaction system was transferred to a flask, nitrogen was introduced into the flask to remove oxygen, and the flask was placed in a 40℃ vacuum drying box for 50min to obtain a mixture containing crosslinked polymers; the mixture containing crosslinked polymers was the crude product of the macromolecular surfactant;

[0091] (4) After the mixture containing crosslinked polymers was cooled to room temperature, it was crushed and dried to obtain the emulsifier.

[0092] Comparative Example 2

[0093] Sodium dodecylbenzenesulfonate was used as the emulsifier.

[0094] Comparative Example 3

[0095] Dodecyltrimethylammonium chloride was used as the emulsifier.

[0096] Comparative Example 4

[0097] TX-100 was used as the emulsifier.

[0098] Performance test

[0099] 50g of white oil and 30g of deionized water were mixed to obtain a crude emulsion. 1g of the macromolecular surfactant prepared in Examples 1-6 and the emulsifiers of Comparative Examples 1-4 were added to 80g of the crude emulsion, respectively, and stirred at a high speed of 8000r / min for 30min to obtain emulsions. The emulsions were subjected to the following performance tests, and the test results are shown in Table 2.

[0100] CMC at 25℃: Platinum plate method was used to measure the surface tension of 7 kinds of surfactants at different molar volume concentrations at (25.0±0.1)℃ using a surface tension meter. Each solution was measured 3 times, and the average value was taken as the measurement result. The γ-c curve was obtained by plotting the surface tension (γ) against the surfactant concentration (c), and the critical micelle concentration was obtained by the inflection point.

[0101] Emulsion viscosity: The viscosity of the emulsion system was tested by a DV-II rotary viscometer, and the test conditions were: No. 0 rotor, rotation speed of 6r / min, and shear time of 5min.

[0102] Emulsion D50 particle size: Measured by a Malvern laser particle size analyzer.

[0103] Emulsion stability: 50mL of the emulsion was taken in a test tube and allowed to stand, and the layering time of the emulsion was observed.

[0104] Table 2

[0105]

[0106] In Table 2, the second row is the test result of the crude emulsion. “-” indicates no data.

[0107] Table 2 shows that the CMC of the emulsifiers of Comparative Examples 1-4 is between 1.4 x 10 -2 and 2.0 x 10 -4 The CMC of the macromolecular surfactants prepared in Examples 1-6 is between 1.2 x 10 -5 and 7.6 x 10 -7 Compared with the emulsifiers of Comparative Examples 1-4, the CMC of the macromolecular surfactants prepared in Examples 1-6 is reduced by at least 1-5 orders of magnitude.

[0108] Table 2 shows that the emulsions stabilized by the emulsifiers of Comparative Examples 1-4 are separated after being placed for 1-2 days; the emulsions stabilized by the macromolecular surfactants prepared in Examples 1-5 are not separated after being placed for 5-8 days; the emulsion stabilized by the macromolecular surfactant prepared in Example 6 is separated after being placed for 4 days. Thus, under the same dosage, the separation time of the emulsion stabilized by the macromolecular surfactants prepared in Examples 1-6 is prolonged by 100-700% compared with the emulsions stabilized by the emulsifiers of Comparative Examples 1-4. The experiment proves that the emulsion stability of the macromolecular surfactants prepared in Examples 1-6 is obviously improved compared with the emulsifiers of Comparative Examples 1-4. It is shown that the macromolecular surfactants prepared in the application can play the emulsion stabilization role even if they are used alone, and the emulsification performance is obviously improved.

[0109] Table 2 shows that the D50 particle size of the emulsions stabilized by the emulsifiers of Comparative Examples 1-4 is between 52 and 82, and the D50 particle size of the emulsions stabilized by the emulsifiers of Examples 1-6 is between 26 and 49. Compared with the emulsions stabilized by the emulsifiers of Comparative Examples 1-4, the D50 particle size of the emulsions stabilized by the macromolecular surfactants prepared in Examples 1-6 is obviously reduced. Thus, the macromolecular surfactants prepared in the application can further reduce the D50 particle size of the emulsion.

[0110] Table 2 shows that the emulsion viscosity of the coarse emulsion is 18, and the emulsion viscosity of the emulsion stabilized by the macromolecular surfactants prepared in Examples 1-6 is 44.6-96.5, and the emulsion viscosity is obviously improved. Thus, the macromolecular surfactants prepared in the application can obviously improve the emulsion viscosity.

[0111] The difference between Example 1-6 and Comparative Example 1 is only that the molar ratio of modified sodium alginate to polyacrylamide in Example 1-6 is within the protection scope of the present application, while the molar ratio of modified sodium alginate to polyacrylamide in Comparative Example 1 is not within the protection scope of the present application. Compared with Comparative Example 1, the CMC of the macromolecular surfactant prepared in Example 1-6 is reduced by 2-5 orders of magnitude, the creaming time of the emulsion stabilized is prolonged by 300-700%, the emulsion D50 particle size is reduced, and the emulsion viscosity is increased. Therefore, compared with the molar ratio of modified sodium alginate to polyacrylamide beyond the protection scope of the present application, the molar ratio of modified sodium alginate to polyacrylamide selected in the present application can further reduce the emulsion CMC and emulsion D50 particle size, improve the stability and emulsion viscosity, and has better technical effects.

Claims

1. A macromolecular surfactant, characterized in that, The macromolecular surfactant is prepared by reacting modified alginate, polyacrylamide, tetramethylethylenediamine and N,N'-methylenebisacrylamide in an aqueous emulsifier solution.

2. The macromolecular surfactant as described in claim 1, characterized in that, The modified alginate is prepared by partially protonating alginate with acid to obtain partially protonated alginate, and then esterifying the partially protonated alginate with fatty alcohol.

3. The macromolecular surfactant as described in claim 2, characterized in that, The acid is selected from one or more of concentrated sulfuric acid, methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid; or / and, The fatty alcohol is selected from one or more of octanol, dodecanol, hexadecyl alcohol, and cholesterol; or / and, The mass ratio of the alginate to the acid is 1-10:1, preferably 1-5:1; or / and, The mass ratio of alginate to fatty alcohol is 1-5:10, preferably 2-5:

10.

4. A method for preparing a macromolecular surfactant as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Mix the emulsifier with water to obtain an aqueous emulsifier solution; (2) Add modified alginate and polyacrylamide to an aqueous emulsifier solution to obtain a mixture; (3) Tetramethylethylenediamine and N,N'-methylenebisacrylamide were added to the mixture to obtain a reaction system. The reaction system was subjected to a cross-linking reaction under vacuum conditions. After the cross-linking reaction was completed, the crude macromolecular surfactant was obtained.

5. The preparation method according to claim 4, characterized in that, It also includes the following steps: (4) After the crude macromolecular surfactant is cooled to room temperature, it is crushed and dried to obtain powdered macromolecular surfactant.

6. The macromolecular surfactant as described in claim 4 or 5, characterized in that, The modified alginate is selected from at least one of modified sodium alginate and modified potassium alginate; or / and, The emulsifier is selected from at least one of octylphenyl polyoxyethylene ether, isomeric decayl alcohol polyoxyethylene ether, and castor oil polyoxyethylene ether.

7. The preparation method according to claim 4 or 5, characterized in that, In step (1), the content of emulsifier in the emulsifier aqueous solution is 1-1.5 wt%; preferably 1-1.2 wt%.

8. The preparation method according to claim 4 or 5, characterized in that, In step (2), the total amount of the modified alginate and polyacrylamide relative to the amount of the emulsifier aqueous solution is 0.15-0.3 g / mL; preferably 0.2-0.3 g / mL.

9. The preparation method according to claim 4 or 5, characterized in that, In step (2), the molar ratio of the modified alginate to the polyacrylamide is 1:1.5-4; preferably 1:1.5-2.

5.

10. The preparation method according to claim 4 or 5, characterized in that, In step (3), The content of tetramethylethylenediamine in the reaction system is 0.04-0.1 wt%; preferably 0.04-0.09 wt%; and / or, The content of N,N'-methylenebisacrylamide in the reaction system is 0.4-0.6 wt%; preferably 0.4-0.5 wt%.

11. The preparation method according to claim 4 or 5, characterized in that, In step (3), The cross-linking reaction temperature is 30–80℃, preferably 40–70℃; The cross-linking reaction time is 30-80 min, preferably 40-50 min.

12. The use of a macromolecular surfactant as described in any one of claims 1-3 in a water-in-oil emulsion or a water-in-oil emulsion.

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