Imidazolinyl polymer phase inversion Pickering fine emulsion method

Abstract

The present invention relates to the fields of functional polymer synthesis, inverse colloids, etc. A method for phase inversion of imidazoline-based polymer Pickering fine emulsion is disclosed. First, a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursors is prepared, and then a hydrothermal reaction is carried out to prepare a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals. It is added to a reactor, an azoimidazoline-based salt initiator is added, ultrasonic biological crushing is carried out, and an acrylic monomer is added for reaction to complete the preparation of an imidazoline-based polymer that synergistically stabilizes the Pickering inverse fine emulsion with magnesium hydroxide nanocrystals. The Pickering inverse fine emulsion is stabilized with an imidazoline-based polymer-modified solid nanoparticle, and an inert gas is introduced to achieve the phase inversion of the Pickering inverse fine emulsion from water / oil type to oil / water type, or carbon dioxide is introduced again to achieve the phase inversion of the Pickering fine emulsion from oil / water type to water / oil type.

Description

Technical Field

[0001] The present invention provides a method for phase inversion of carbon dioxide-responsive imidazoline-based polymer Pickering fine emulsions. Imidazoline-based polymer-modified solid nanoparticles are used to stabilize Pickering fine emulsions, and carbon dioxide or inert gas is introduced to achieve the phase inversion of Pickering inverse fine emulsion from water / oil type to oil / water type or the phase inversion of Pickering fine emulsion from oil / water type to water / oil type. The present invention relates to the fields of functional polymer synthesis, inverse colloids, inorganic nanoparticle synthesis, and green functional materials, etc. Background Art

[0002] Pickering emulsions are emulsions in which ultrafine solid particles can be used as water-in-oil or oil-in-water emulsifiers. The type of emulsion depends on which phase preferentially wets the solid particles. Usually, the phase that preferentially wets the solid particles is the outer phase. For example, sometimes the solid particles are more easily wetted by the oil phase, and the emulsion is of the W / O (water-in-oil, oil / water) type; conversely, if the solid particles are more easily wetted by the water phase, the emulsion is of the O / W (oil-in-water, water / oil) type. Solid powders of emulsifiers include clay, silica, metal hydroxides, graphite, carbon black, etc. The stability of the emulsion is related to the concentration of solid particles, particle size, wettability, etc. Pickering fine emulsions combine the characteristics of fine emulsions and Pickering emulsions, and have the advantages of low cost, environmental friendliness, and strong emulsion stability. The stability of Pickering fine emulsions mainly depends on the adsorption ability of solid particles at the interface. Solid particles adsorb on the oil / water interface to form a dense film, reducing the possibility of coalescence between droplets; the electrostatic repulsion force between particles can also inhibit the phenomena of emulsion stratification or sedimentation.

[0003] Imidazoline, also known as m-diazacyclopentene, is a nitrogen-containing heterocyclic compound, presenting white needle-like crystals, and the group is alkaline. The imidazoline groups on the polymer chain will generate positive charges and be protonated under the action of carbon dioxide, resulting in changes in the hydrophilic-lipophilic properties of the imidazoline-based polymer; when an inert gas is introduced into the system and slightly heated, the protonated polymer will regenerate imidazoline groups again. Therefore, imidazoline-based polymers are a kind of stimuli-responsive polymers.

[0004] The present invention uses imidazoline-based carbon dioxide-responsive polymers and magnesium hydroxide nanocrystals to synergistically stabilize Pickering fine emulsions, and carbon dioxide or nitrogen is introduced to achieve the phase inversion of water / oil type Pickering inverse fine emulsions to oil / water type or the phase inversion of Pickering fine emulsions from oil / water type to water / oil type. It relates to the fields of functional polymer synthesis, inverse colloids, self-assembly, and green functional materials, etc. This invention has clear practical value and innovation. Summary of the Invention

[0005] The object of the present invention is to prepare an imidazoline-based carbon dioxide-responsive polymer, and an imidazoline-based polymer cooperates with magnesium hydroxide nanocrystals-stabilized Pickering inverse fine emulsion to realize a method for phase inversion of Pickering fine emulsion by introducing carbon dioxide or inert gas.

[0006] The method for phase inversion of imidazoline-based polymer Pickering fine emulsion is carried out according to the following steps:

[0007] (1) Prepare a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursor

[0008] At room temperature, a quantitative magnesium salt aqueous solution, a quantitative non-ionic reactive emulsifier, and a quantitative oily solvent are mixed, and then pulverized at a certain temperature in a set manner for a certain time, and then maintained in an ultrasonic state. During ultrasonic treatment, a single-channel microinjector is used to drop the alkaline solution into the reactor. The preparation of the Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursor is completed.

[0009] In step (1), the magnesium salt solution is a water-soluble salt such as magnesium sulfate, magnesium nitrate, or magnesium chloride; the non-ionic reactive emulsifier is a nonylphenol polyoxyethylene ether acrylate polymer with 10-20 ethylene oxide units, commercially available; the oily solvent refers to heavy liquid paraffin (density 0.860-0.890 g / cm³), etc.; the alkaline solution is an aqueous solution of sodium hydroxide or potassium hydroxide, etc. After the magnesium salt aqueous solution, the non-ionic reactive emulsifier, and the oily solvent are mixed, they are pulverized at a high power of 500 W in an ultrasonic biological pulverizer at 80% power for 5 minutes at a temperature of 10°C; then the ultrasonic state is maintained at a power of 300 W, and the alkaline solution is dropped at a rate of one-tenth of the mass of the alkaline solution per minute.

[0010] In step (1), the mass concentration of the magnesium salt aqueous solution is 0.1-0.5%; the mass concentration of the alkaline solution is 5-10%. The mass ratio of the magnesium salt aqueous solution, the non-ionic reactive emulsifier, the oily solvent, and the alkaline solution is 40:1-2:50:1.

[0011] (2) Preparation of a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals

[0012] A certain amount of the Pickering inverse fine emulsion of magnesium hydroxide nanocrystal precursor prepared in step (1) is loaded into a high-pressure reactor, and then placed in an oven at a set temperature for a predetermined time of insulation, and then taken out to obtain a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals.

[0013] In the method of step (2), the high-pressure reactor is a synthesis reactor with a polytetrafluoroethylene inner sleeve and a stainless steel outer sleeve. The set temperature of the oven is 70-80°C, and the predetermined insulation time is 4-6 hours.

[0014] In the method described in step (2), the ratio of the mass of a certain amount of the Pickering inverse fine emulsion prepared in step (1) to the volume of the autoclave is 0.3 - 0.5 g / mL.

[0015] (3) Preparation of imidazoline-based polymers for synergistically stabilizing Pickering inverse fine emulsions

[0016] At room temperature, add a quantified Pickering inverse fine emulsion of magnesium hydroxide nanocrystals prepared in step (2) into a reactor protected by carbon dioxide gas; add a quantified aqueous solution of an initiator with a mass concentration; then transfer it to an ultrasonic cell disruptor. After mixing, crush it for 10 minutes at a high power of 500 W and a power state of 70% at a temperature of 5°C; after high-power crushing, transfer it to a low-power state of 200 W and raise the temperature to 70 - 80°C. Use a single-channel microinjector to dropwise add a quantified specific monomer into the reactor. After the addition is completed, maintain the reaction temperature for a certain period of time; then lower the temperature to room temperature to complete the preparation of imidazoline-based polymers for synergistically stabilizing Pickering inverse fine emulsions with magnesium hydroxide nanocrystals.

[0017] The water-soluble initiator in step (3) is an azoimidazoline-based salt such as 2,2'-azobis(2-hydroxyethyl)imidazoline propane dihydrochloride, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, or 2,2'-azobis(2-imidazoline-2-yl)propane dihydrochloride, etc.; the specific monomer is 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, or 2-hydroxypropyl acrylate, etc. Maintain ultrasonic treatment for 150 minutes. After the ultrasonic treatment ends, the reaction solution is cooled to room temperature.

[0018] In step (3), the initiator is dissolved to form an aqueous solution with a mass concentration of 1.0 - 2.0%. The mass ratio of the water-soluble initiator solution, the Pickering inverse fine emulsion of magnesium hydroxide nanocrystals in step (2), and the specific monomer is 5 - 10:100:1 - 2, and the dropping rate of the specific monomer is 20% of the monomer mass fraction per minute.

[0019] (4) Phase inversion Pickering fine emulsion of imidazoline-based polymers

[0020] At room temperature, the Pickering inverse fine emulsion (water-in-oil type) reactor stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals prepared in step (3) is heated up, and an inert gas is bubbled through for a certain period of time. The inverse fine emulsion in the reactor is stratified. After being pulverized by an ultrasonic cell disruptor for a certain period of time, the Pickering inverse fine emulsion colloid stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals undergoes phase inversion, and the Pickering inverse fine emulsion (water-in-oil type) is inverted into a Pickering fine emulsion (oil-in-water type); the introduction of the inert gas is stopped and the temperature of the emulsion is lowered, and carbon dioxide is bubbled through again for a certain period of time. The fine emulsion in the reactor is stratified again. After being pulverized by an ultrasonic cell disruptor for a certain period of time, the Pickering fine emulsion colloid stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals returns to the inverse phase state of step (3), realizing the re-inversion of the Pickering fine emulsion (oil-in-water type) into a Pickering inverse fine emulsion (water-in-oil type).

[0021] In the method described in step (4), the inert gas can be nitrogen or argon. It is heated up to 50 - 60 °C, the gas flow rate is 1 cubic decimeter per minute under standard atmospheric pressure, and the gas is bubbled for 10 - 20 minutes; the introduction of the inert gas is stopped and the emulsion is cooled to 10 - 20 °C, and then carbon dioxide gas is bubbled through for 10 - 20 minutes, and the gas flow rate is 1 cubic decimeter per minute under standard atmospheric pressure; the ultrasonic cell disruptor has a high power of 500 W and pulverizes at 70% power state for 5 minutes.

[0022] In the present invention, the Pickering inverse fine emulsion is stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals, and the phase inversion of the Pickering fine emulsion is achieved by introducing an inert gas, or the phase state is restored by introducing carbon dioxide again. The Pickering fine emulsion colloid prepared by this method has potential application prospects in the fields of regulating carbon dioxide absorption and utilization and intelligent macromolecules. The present invention has the following advantages:

[0023] 1. Magnesium hydroxide nanocrystals can be prepared by adding a non-ionic reactive emulsifier, dropwise adding an alkali solution and a heat treatment method during the preparation process of the Pickering inverse fine emulsion, and it can conditionally absorb or release carbon dioxide; the magnesium hydroxide nanocrystals stabilize the Pickering inverse fine emulsion and the imidazoline-based carbon dioxide-responsive polymer cooperate to invert or restore the Pickering inverse fine emulsion, and the cooperative stabilization time of the fine emulsion is extended to more than 30 days;

[0024] 2. An imidazoline-based carbon dioxide-responsive polymer can be obtained by using an azoimidazoline-based initiator to initiate, a reactive initiator and a hydroxy vinyl monomer to cooperate in stabilizing the Pickering inverse fine emulsion, and the phase inversion of the Pickering fine emulsion is achieved by introducing an inert gas, or the phase state is restored by introducing carbon dioxide again. Detailed implementation mode

[0025] The present invention will be further described in detail below with reference to examples.

[0026] Example 1

[0027] (1) Preparation of Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursor

[0028] At room temperature, 40 g of 0.1% magnesium sulfate aqueous solution, 1 g of non-ionic reactive emulsifier nonylphenol polyoxyethylene ether acrylate polymer (n = 10), and 50 g of heavy liquid paraffin (density 0.860 g / cm³) were mixed, and then pulverized with a high-power ultrasonic biological pulverizer at 500 W at 80% power state for 5 minutes, with the temperature at 10 °C; then the ultrasonic state was maintained at 300 W. During the ultrasonic treatment, a 5% mass concentration sodium hydroxide solution of 1.0 g was added dropwise to the reactor at a rate of 0.1 g / min using a single-channel microinjector. The preparation of the Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursor was completed.

[0029] (2) Preparation of Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals

[0030] 30 g of the quantitatively prepared Pickering inverse fine emulsion of magnesium hydroxide nanocrystal precursor obtained in step (1) was charged into a 100 mL high-pressure reactor with an inner sleeve of polytetrafluoroethylene and an outer sleeve of stainless steel, and then placed in an oven set at 80 °C for heat preservation for a predetermined 4 hours, and taken out to obtain the Pickering inverse fine emulsion of magnesium hydroxide nanocrystals. The number average particle size of the magnesium hydroxide nanocrystals was 1 nm, the Z-average particle size of the inverse fine emulsion was 180 nm, and the static stability time was 48 hours.

[0031] (3) Preparation of imidazoline-based polymer for synergistically stabilizing Pickering inverse fine emulsion

[0032] At room temperature, 20 g of the magnesium hydroxide nanocrystal Pickering inverse miniemulsion prepared in step (2) was added to a reactor protected by carbon dioxide gas; 1 g of an aqueous solution of an initiator, 1.0% by mass of azobis(imidazolinyl)propane dihydrochloride, was added; subsequently, it was transferred to an ultrasonic cell disruptor. After mixing, it was pulverized by the ultrasonic cell disruptor at a high power of 500 W in a 70% power state for 10 minutes at a temperature of 5 °C; after high-power pulverization, it was transferred to a low-power state of 200 W, and the temperature was raised to 70 °C. A specific monomer, 0.2 g of 2-hydroxyethyl methacrylate, was added dropwise to the reactor at a rate of 0.04 g / min using a single-channel microinjector, and ultrasonic treatment was maintained for 150 minutes. After the ultrasonic treatment ended, the reaction solution was cooled to room temperature. The preparation of the imidazolinyl polymer that synergistically stabilizes the inverse miniemulsion with magnesium hydroxide nanocrystals was completed. The Z-average particle size of the inverse miniemulsion was 150 nm, and the static stability time was more than 30 days; the significantly increased standing time indicates that the imidazolinyl polymer synergistically stabilizes the Pickering inverse miniemulsion with magnesium hydroxide nanocrystals.

[0033] (4) Imidazolinyl polymer phase-inverted Pickering miniemulsion

[0034] At room temperature, nitrogen gas was introduced into the reactor of the Pickering inverse miniemulsion stabilized by the imidazolinyl polymer and magnesium hydroxide nanocrystals prepared in step (3) at a gas flow rate of 1 dm³ / min under standard pressure, and bubbling was carried out while raising the temperature to 50 °C for 20 minutes. The inverse miniemulsion in the reactor was stratified. After pulverizing with an ultrasonic cell disruptor at a high power of 500 W in a 70% power state for 5 minutes, the phase inversion of the Pickering inverse miniemulsion colloid stabilized by the imidazolinyl polymer and magnesium hydroxide nanocrystals occurred; the introduction of the inert gas was stopped and the emulsion was cooled to 10 °C, and carbon dioxide was introduced again at a flow rate of 1 dm³ / min under standard pressure. After bubbling for another 20 minutes, the miniemulsion in the reactor was stratified again. After pulverizing with an ultrasonic cell disruptor at a high power of 500 W in a 70% power state for 5 minutes, the Pickering miniemulsion colloid stabilized by the imidazolinyl polymer and magnesium hydroxide nanocrystals returned to the inverse state of step (3).

[0035] Example 2

[0036] (1) Preparation of a Pickering inverse miniemulsion stabilized by a magnesium hydroxide nanocrystal precursor

[0037] At room temperature, 40 g of 0.5% magnesium nitrate aqueous solution, 2 g of nonionic reactive emulsifier nonylphenol polyoxyethylene ether acrylate polymer (n=20) and 50 g of heavy liquid paraffin (density 0.890 g / cm3) were mixed and then crushed with an ultrasonic bio-crusher at high power 500 W at 80% power for 5 minutes at 10°C; then the ultrasonic state was maintained at 300 W. During the ultrasonication, 1.0 g of 10% mass concentration potassium hydroxide alkaline solution was added dropwise at 0.1 g / min into the reactor using a single-channel micro-injector.

[0038] (2) Preparation of Pickering inverse miniemulsion stabilized by magnesium hydroxide nanocrystals

[0039] 50 g of the quantitative magnesium hydroxide nanocrystal precursor Pickering reverse miniemulsion prepared in step (1) was placed in a 100 mL autoclave with a polytetrafluoroethylene inner sleeve and a stainless steel outer sleeve, and then placed in an oven set at a temperature of 70° C. for a predetermined 6 hours, and the magnesium hydroxide nanocrystal Pickering reverse miniemulsion was obtained. The number average particle size of the magnesium hydroxide nanocrystals was 5 nanometers, the Z average particle size of the reverse miniemulsion was 100 nanometers, and the static stability time was 72 hours.

[0040] (3) Preparation of imidazoline-based polymers for synergistic stabilization of Pickering inverse miniemulsions

[0041] At room temperature, 20 grams of the magnesium hydroxide nanocrystal Pickering reverse miniemulsion prepared in step (2) is added to a reactor protected by carbon dioxide gas; 2 grams of a 2.0% mass concentration of azobishydroxyethyl imidazolinyl propane dihydrochloride initiator aqueous solution is added; then it is transferred to an ultrasonic bio-crusher, mixed and crushed by the ultrasonic bio-crusher at a high power of 500W at a power state of 70% for 10 minutes at a temperature of 5°C; after high-power crushing, it is transferred to a low power state of 200W, and the temperature is raised to 80°C. A single-channel micro-injector is used to drop a specific monomer 0.4 grams of hydroxyethyl acrylate into the reactor at a speed of 0.08 grams / minute, and the ultrasound is maintained for 150 minutes. After the ultrasound is completed, the reaction solution is cooled to room temperature. The preparation of the imidazoline-based polymer that cooperates with the magnesium hydroxide nanocrystal to stabilize the reverse miniemulsion is completed. The Z average particle size of the reverse miniemulsion is 80 nanometers, and the static stability time is more than 30 days; the significant increase in the static time indicates that the imidazoline-based polymer cooperates with the magnesium hydroxide nanocrystal to stabilize the Pickering reverse miniemulsion.

[0042] (4) Imidazolinyl polymer phase inversion Pickering miniemulsion

[0043] At room temperature, nitrogen was introduced into the Pickering inverse fine emulsion reactor stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals prepared in step (3) at a flow rate of 1 cubic decimeter per minute under standard atmospheric pressure. Bubbling was carried out and the temperature was raised to 60 °C, and bubbling was continued for 10 minutes. The inverse fine emulsion in the reactor was stratified. After the ultrasonic cell disruptor with a high power of 500 W was pulverized at 70% power for 5 minutes, the Pickering inverse fine emulsion colloid stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals underwent phase inversion; the introduction of the inert gas was stopped and the emulsion was cooled to 20 °C. Then, carbon dioxide was bubbled in again at a gas flow rate of 1 cubic decimeter per minute under standard atmospheric pressure. After 10 minutes, the fine emulsion in the reactor was stratified again. After the ultrasonic cell disruptor with a high power of 500 W was pulverized at 70% power for 5 minutes, the Pickering fine emulsion colloid stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals returned to the inverse phase state of step (3).

[0044] Example 3

[0045] (1) Preparation of Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursor

[0046] At room temperature, 40 g of 0.3% magnesium chloride aqueous solution, 1.5 g of non-ionic reactive emulsifier nonylphenol polyoxyethylene ether acrylate polymer (n = 15) and 50 g of heavy liquid paraffin (density 0.870 g / cm³) were mixed, and then pulverized with an ultrasonic cell disruptor at a high power of 500 W at 80% power for 5 minutes at a temperature of 10 °C; then the ultrasonic state was maintained at a power of 300 W. During the ultrasonic treatment, 1.0 g of 8% mass concentration sodium hydroxide alkaline solution was added dropwise to the reactor at a rate of 0.1 g / min using a single-channel microinjector. The preparation of the Pickering inverse fine emulsion stabilized by the magnesium hydroxide nanocrystal precursor was completed.

[0047] (2) Preparation of Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals

[0048] 40 g of the quantitative Pickering inverse fine emulsion of magnesium hydroxide nanocrystal precursor prepared in step (1) was loaded into a high-pressure reactor with an inner sleeve of polytetrafluoroethylene and an outer sleeve of stainless steel with a volume of 100 mL, and then placed in an oven set at a temperature of 75 °C and kept warm for 5 hours. After taking out, the Pickering inverse fine emulsion of magnesium hydroxide nanocrystals was obtained. The number average particle size of the magnesium hydroxide nanocrystals was 3 nm, the Z-average particle size of the inverse fine emulsion was 150 nm, and the static stability time was 42 hours.

[0049] (3) Preparation of imidazoline-based polymer for co-stabilizing Pickering inverse fine emulsion

[0050] At room temperature, 20 g of the magnesium hydroxide nanocrystal Pickering inverse miniemulsion prepared in step (2) was added to a reactor protected by carbon dioxide gas; 1.5 g of an aqueous solution of an initiator, 1.5% by mass of 2,2'-azobis(2-methylpropionamidine) dihydrochloride, was added; then it was transferred to an ultrasonic cell disruptor. After mixing, it was pulverized by the ultrasonic cell disruptor at a high power of 500 W in a 70% power state for 10 minutes at a temperature of 5 °C; after high-power pulverization, it was transferred to a low-power state of 200 W, and the temperature was raised to 75 °C. A specific monomer, 0.3 g of 2-hydroxyethyl acrylate, was added dropwise to the reactor at a rate of 0.06 g / min using a single-channel microinjector, and ultrasonication was maintained for 150 minutes. After the ultrasonication ended, the reaction solution was cooled to room temperature. The preparation of the imidazoline-based polymer that synergistically stabilizes the inverse miniemulsion with magnesium hydroxide nanocrystals was completed. The Z-average particle size of the inverse miniemulsion was 120 nm, and the static stability time was more than 30 days; the significantly increased static time indicates that the imidazoline-based polymer synergistically stabilizes the Pickering inverse miniemulsion with magnesium hydroxide nanocrystals.

[0051] (4) Phase inversion of imidazoline-based polymer Pickering miniemulsion

[0052] At room temperature, argon was introduced into the reactor of the Pickering inverse miniemulsion synergistically stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals prepared in step (3) at a flow rate of 1 dm³ / min under standard atmospheric pressure, and bubbling was carried out while raising the temperature to 55 °C for 15 minutes. The inverse miniemulsion in the reactor was stratified. After pulverizing for 5 minutes by the ultrasonic cell disruptor at a high power of 500 W in a 70% power state, the phase inversion of the Pickering miniemulsion colloid synergistically stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals occurred; the introduction of the inert gas was stopped and the emulsion was cooled to 15 °C, and then carbon dioxide was bubbled in again at a gas flow rate of 1 dm³ / min under standard atmospheric pressure. After 15 minutes, the miniemulsion in the reactor was stratified again. After pulverizing for 5 minutes by the ultrasonic cell disruptor at a high power of 500 W in a 70% power state, the Pickering miniemulsion colloid synergistically stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals returned to the inverse state of step (3).

[0053] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and apply the present invention. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the embodiments herein, and all modifications made by those skilled in the art according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. Imidazolinyl polymer phase inversion Pickering fine emulsion method, characterized in that: The specific steps are as follows: (1)Prepare a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursors: At room temperature, mix an aqueous magnesium salt solution, a nonionic reactive emulsifier, and an oily solvent. After ultrasonic crushing, maintain the ultrasonic state and dropwise add an alkaline solution thereto to obtain a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursors; (2)Prepare a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals: Load the Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystal precursors prepared in step (1) into a high-pressure reactor, and obtain a Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals after a hydrothermal reaction; (3)Prepare an imidazoline-based polymer for co-stabilizing the Pickering inverse fine emulsion: At room temperature, add the Pickering inverse fine emulsion stabilized by magnesium hydroxide nanocrystals prepared in step (2) to a reactor protected by carbon dioxide gas; add an aqueous solution of an azoimidazoline-based salt initiator; after mixing, transfer it to a ultrasonic cell disruptor and crush for a certain time, maintain the ultrasound and raise the temperature, and dropwise add an acrylic monomer to the reactor. After the addition is completed, continue to maintain the reaction temperature for the reaction; then lower the temperature to room temperature to complete the preparation of the imidazoline-based polymer for co-stabilizing the inverse fine emulsion by magnesium hydroxide nanocrystals, and obtain a Pickering inverse fine emulsion co-stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals; (4)Imidazoline-based polymer phase-inverted Pickering fine emulsion: At room temperature, raise the temperature of the reactor of the Pickering inverse fine emulsion co-stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals prepared in step (3), introduce an inert gas for bubbling, and the inverse fine emulsion in the reactor is stratified. After crushing with a ultrasonic cell disruptor, the colloid of the Pickering inverse fine emulsion co-stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals undergoes phase inversion; stop introducing the inert gas and lower the temperature of the emulsion, then bubble in carbon dioxide again, and the fine emulsion in the reactor is stratified again. After crushing with a ultrasonic cell disruptor, the colloid of the Pickering fine emulsion co-stabilized by the imidazoline-based polymer and magnesium hydroxide nanocrystals returns to the inverse state of step (3).

2. The method for preparing an imidazoline-based polymer phase-inverting Pickering fine emulsion according to claim 1, wherein: The aqueous magnesium salt solution in step (1) is a water-soluble salt such as magnesium sulfate, magnesium nitrate, or magnesium chloride; the nonionic reactive emulsifier is a nonylphenol polyoxyethylene ether acrylate polymer with the number of ethylene oxide units being 10-20; the oily solvent refers to heavy liquid paraffin; the alkaline solution is an aqueous solution of sodium hydroxide or potassium hydroxide.

3. The imidazoline-based polymer phase inversion Pickering fine emulsion method according to claim 1, wherein: After mixing the aqueous magnesium salt solution, the nonionic reactive emulsifier, and the oily solvent in step (1), crush them at a high power of 500 W and 80% power state for 5 minutes with a ultrasonic cell disruptor at a temperature of 10°C; then maintain the ultrasonic state at a power of 300 W and dropwise add the alkaline solution at a rate of one-tenth of the mass of the alkaline solution per minute.

4. The imidazoline-based polymer phase inversion Pickering fine emulsion method according to claim 1, characterized in that: Step (1): The mass concentration of the magnesium salt aqueous solution is 0.1 - 0.5%; the mass concentration of the alkaline solution is 5 - 10%; the mass ratio of the magnesium salt aqueous solution, the non-ionic reactive emulsifier, the oily solvent and the alkaline solution is 40:1 - 2:50:

1.

5. The method for preparing an imidazolinyl polymer phase-inverted Pickering fine emulsion according to claim 1, wherein: Step (2): In the method, the high-pressure reactor is a synthesis kettle with a polytetrafluoroethylene inner sleeve and a stainless steel outer sleeve; the temperature of the hydrothermal reaction is 70 - 80 °C, and the heat preservation reaction time is 4 - 6 hours.

6. The method for preparing an imidazoline-based polymer phase-inverting Pickering fine emulsion according to claim 1, wherein: Step (3): The azo imidazoline-based salt initiator is 2,2'-azobis(2-hydroxyethyl)imidazoline propane dihydrochloride, 2,2'-azobis(2-methylpropionamidine) dihydrochloride or 2,2'-azobis(2-imidazoline-2-yl)propane dihydrochloride.

7. The imidazoline-based polymer phase inversion Pickering fine emulsion method according to claim 1, characterized in that: Step (3): The acrylic monomer is 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, hydroxyethyl acrylate or hydroxypropyl acrylate.

8. The method for preparing an imidazolinyl polymer phase-inverting Pickering fine emulsion according to claim 1, characterized in that: After mixing in Step (3), it is pulverized by an ultrasonic biological pulverizer at a high power of 500 W in a 70% power state for 10 minutes at a temperature of 5 °C; after high-power pulverization, it is transferred to a low-power state of 200 W, the temperature is raised to 70 - 80 °C, and the acrylic monomer is added dropwise while maintaining ultrasonic treatment for 150 minutes.

9. The imidazolinyl polymer phase inversion Pickering fine emulsion method according to claim 1, characterized in that: The mass concentration of the initiator aqueous solution is 1.0 - 2.0%; the mass ratio of the initiator aqueous solution, the magnesium hydroxide nanocrystal Pickering inverse fine emulsion in Step (2) and the acrylic monomer is 5 - 10:100:1 - 2.

10. The imidazoline-based polymer phase inversion Pickering fine emulsion method according to claim 1, wherein: In Step (4), the inert gas is nitrogen or argon, the temperature is raised to 50 - 60 °C, the gas flow rate is 1 cubic decimeter per minute under standard pressure; the ultrasonic biological pulverizer is used at a high power of 500 W in a 70% power state for 5 minutes.