Surfactant as well as preparation method and application thereof

Abstract

The invention discloses a surfactant as well as a preparation method and application thereof.Hydrophilic groups (such as ethylene oxide EO and propylene oxide PO) are grafted on siloxane molecules to form an amphiphilic structure, and the amphiphilic structure is self-assembled in a solution to form nano-micelles of a core-shell structure. The hydrophobic core of the micelle can efficiently wrap insoluble pesticide raw medicine molecules, so that the solubility of the raw medicine is remarkably improved. Meanwhile, titanium dioxide nanoparticles are introduced as a stable structure in a micelle core, so that the dispersibility and the agglomeration resistance of the micelle are further enhanced, and the particle size distribution of the preparation is more uniform. Through the structural design, the surface tension of the preparation is remarkably reduced, the solubility of the raw pesticide is enhanced, the stability and the pesticide effect of the preparation are improved, and the usage amount of the pesticide and the environmental pollution are reduced.

Description

Technical Field

[0001] The invention belongs to the field of surfactants, and in particular relates to a surfactant and a preparation method and application thereof. Background Art

[0002] Most pesticide raw materials are hydrophobic or poorly soluble compounds with poor water solubility. They are difficult to be directly applied to water-based preparations or water dilution systems, which limits the utilization efficiency of pesticides and increases the amount of pesticides applied. At the same time, they may cause environmental pollution and drug residues. In order to solve these problems, traditional pesticide preparations usually use solvents, emulsifiers, solubilizers or adjuvants to improve the solubility and dispersibility of the raw materials. However, these methods often have limitations such as insufficient formulation stability, complex preparation process, high cost, and adverse effects of adjuvants on the environment. Therefore, finding an efficient, stable and environmentally friendly solubilization technology has become a research hotspot in the field of pesticide formulations.

[0003] In recent years, the study of solubilization and dispersion of poorly soluble pesticides by surfactants has gained wide attention. Surfactant molecules can self-assemble into core-shell micelles in solution due to their amphiphilic structure, and wrap poorly soluble molecules with their hydrophobic core, thereby significantly improving their solubility. However, traditional surfactants have limited solubilization ability, uneven particle size distribution, and easy agglomeration in formulations, which restricts their widespread application.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a surfactant and a preparation method and application thereof, and solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0007] A method for preparing a surfactant comprises the following steps:

[0008] S1: 100 parts by weight of polymethyl hydrogen siloxane is dissolved in 50 to 150 parts by weight of ethanol to form a uniform siloxane base solution;

[0009] S2: adding ethylene oxide (EO) and propylene oxide (PO) to the siloxane substrate solution, and reacting them under the action of a platinum-based catalyst so that the hydrophilic groups are combined with the siloxane molecules to form a preliminarily modified siloxane substrate;

[0010] S3: adding titanium dioxide nanoparticles to the preliminarily modified siloxane substrate;

[0011] S4: transferring the above mixed system into a reaction kettle, stirring it fully, and controlling the reaction temperature at 80-120° C. for a reaction time of 2-6 hours to ensure sufficient bonding and dispersion between the siloxane base, the hydrophilic group and the titanium dioxide particles, and finally forming nanomicelles with a core-shell structure;

[0012] S5: Cooling the mixture after the reaction to room temperature, washing the reaction product by adding acetone to remove unreacted residual substances, and then removing the solvent by freeze drying to finally obtain a surfactant.

[0013] Preferably, the amount of the platinum-based catalyst used in step S2 is 0.01% to 1% of the mass of the polymethylhydrogensiloxane.

[0014] Preferably, in step S2, the total weight of EO and PO is 10-50 parts by weight, wherein the molar ratio of EO to PO is 1-5:1, and the hydrophilic group is grafted onto the siloxane molecule through the copolymerization reaction of ethylene oxide (EO) and propylene oxide (PO).

[0015] Preferably, in step S2, the reaction is carried out under the action of a platinum-based catalyst by stirring at 80-120° C. for 2 to 6 hours.

[0016] Preferably, the metal oxide nanoparticles in step S3 are subjected to ultrasonic dispersion treatment before being added, and the ultrasonic time is 10 to 30 minutes to ensure that the particles are evenly distributed in the reaction system.

[0017] Preferably, the amount of titanium dioxide added in step S3 is 5-20 parts by weight of the siloxane base material, and the particle size of titanium dioxide is 10-50 nm.

[0018] Preferably, the final particle size distribution of the surfactant in step S5 is 10-100 nm, and its surface tension can be reduced to below 20 mN / m.

[0019] Preferably, the freeze-drying temperature in step S5 is controlled at -20°C to -40°C.

[0020] In a second aspect, the present invention provides a surfactant, which is prepared by the above-mentioned preparation method.

[0021] In a third aspect, the present invention provides the application of the above-mentioned surfactant in solubilizing the pesticide original drug, and the specific application steps include:

[0022] According to the formulation requirements of the pesticide preparation, weigh an appropriate amount of pesticide technical (such as imidacloprid, glyphosate or carbendazim), usually the main part of the total mass of the target preparation; weigh the surfactant at the same time, the amount is generally 0.5% to 5% of the mass of the pesticide technical; prepare the required solvent (such as water, ethanol, toluene or a mixed solvent thereof), and ensure that all raw materials meet the purity and specification requirements;

[0023] Add the pesticide technical and the surfactant into a stirring device according to the formula ratio, and stir at a speed of 300-500 rpm for 10-20 minutes to allow the surfactant to evenly coat the surface of the pesticide particles;

[0024] Slowly add the selected solvent (such as water or ethanol) into the mixed system. The proportion of the solvent is determined according to the formulation requirements, generally 50% to 80% of the total mass of the system; at the same time, keep stirring continuously to make the pesticide technical initially dispersed in the solvent, and the surfactant and the solvent are fully mixed to form a stable dispersion.

[0025] The mixed solution is transferred to a reactor, and the system is heated to 50-80°C, and reacted for 20-30 minutes under continuous stirring. During this process, the surfactant combines with the pesticide technical through its hydrophilic and hydrophobic groups to form a stable core-shell structure nano-micelle, thereby significantly improving the solubility and uniformity of the pesticide technical.

[0026] The corresponding post-treatment is carried out according to the type of target pesticide formulation: for aqueous solution (SL), the mixed solution is directly cooled to room temperature and stabilized after adding; for emulsifiable concentrate (EC), emulsifier and cosolvent are further added to form a stable emulsion; for suspension concentrate (SC), anti-settling agent is added after high-speed shear dispersion until the particle size is uniform; for water dispersible granules (WDG), granules are formed by spray drying after adding granulation excipients;

[0027] The performance of the formulation products is tested, including indicators such as particle size distribution (10-100nm), surface tension (whether it is reduced to below 20mN / m) and solution stability; after confirming that the product meets the quality standards of pesticide formulations, it is diluted to the use concentration and sprayed on the crop surface or target area to ensure efficient efficacy.

[0028] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described below at the same time:

[0029] The present invention forms an amphiphilic structure by grafting hydrophilic groups (such as ethylene oxide EO and propylene oxide PO) on siloxane molecules, so that the siloxane molecules are self-assembled into nano micelles with a core-shell structure in a solution. The hydrophobic core of the micelle can efficiently encapsulate the poorly soluble pesticide original drug molecules, thereby significantly improving the solubility of the original drug. At the same time, titanium dioxide nanoparticles are introduced as a stable structure in the micelle core, further enhancing the dispersibility and anti-agglomeration ability of the micelle, making the particle size distribution of the preparation more uniform. Through this structural design, not only the surface tension of the preparation is significantly reduced, the solubility of the pesticide original drug is enhanced, but also the stability and efficacy of the preparation are improved, and the usage amount of the pesticide and environmental pollution are reduced.

[0030] The specific embodiments of the present invention are described in further detail below. DETAILED DESCRIPTION

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0033] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0034] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0035] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0036] In this embodiment, a method for preparing a surfactant comprises the following steps:

[0037] S1: 100 parts by weight of polymethyl hydrogen siloxane is dissolved in 50 to 150 parts by weight of ethanol to form a uniform siloxane base solution;

[0038] S2: adding ethylene oxide (EO) and propylene oxide (PO) to the siloxane substrate solution, and reacting them under the action of a platinum-based catalyst so that the hydrophilic groups are combined with the siloxane molecules to form a preliminarily modified siloxane substrate;

[0039] S3: adding titanium dioxide nanoparticles to the preliminarily modified siloxane substrate;

[0040] S4: transferring the mixed system into a reaction kettle, stirring it fully, and controlling the reaction temperature at 80-120° C. for 2-6 hours to finally form nanomicelles with a core-shell structure;

[0041] S5: Cooling the mixture after the reaction to room temperature, washing the reaction product by adding acetone to remove unreacted residual substances, and then removing the solvent by freeze drying to finally obtain a surfactant.

[0042] In this embodiment, the amount of the platinum-based catalyst used in step S2 is 0.01% to 1% of the mass of the polymethylhydrogensiloxane.

[0043] In this embodiment, the total weight of EO and PO in step S2 is 10-50 parts by weight, wherein the molar ratio of EO to PO is 1-5:1.

[0044] In this embodiment, when the reaction is carried out under the action of the platinum-based catalyst in step S2, the reaction is stirred at 80-120° C. for 2 to 6 hours.

[0045] In this embodiment, the metal oxide nanoparticles in step S3 are subjected to ultrasonic dispersion treatment before being added, and the ultrasonic time is 10 to 30 minutes to ensure that the particles are evenly distributed in the reaction system.

[0046] In this embodiment, the amount of titanium dioxide added in step S3 is 5-20 parts by weight of the siloxane base material, and the particle size of titanium dioxide is 10-50 nm.

[0047] In this embodiment, the final particle size distribution of the surfactant in step S5 is 10-100 nm, and its surface tension can be reduced to below 20 mN / m.

[0048] In this embodiment, the freeze-drying temperature in step S5 is controlled at -20°C to -40°C.

[0049] It should be noted that all raw materials in the examples of the present invention were obtained through commercial sources.

[0050] Embodiment 1: In this embodiment, a method for preparing a surfactant is provided, comprising the following steps:

[0051] S1: Weigh 100 parts by weight of polymethylhydrogensiloxane (linear siloxane), dissolve it in 100 parts by weight of anhydrous ethanol, and stir it to form a siloxane base solution. At the same time, weigh a mixture of ethylene oxide (EO) and propylene oxide (PO), the total mass of which is 30 parts by weight of the siloxane mass, wherein the molar ratio of EO to PO is 2:1, and prepare a platinum-based catalyst, the amount of which is 0.1% of the mass of the siloxane base.

[0052] S2: Add the prepared siloxane substrate solution into the reactor, and slowly add the mixture of ethylene oxide and propylene oxide under stirring at 500 rpm. Add a platinum-based catalyst at a reaction temperature of 80°C, continue stirring and keep the reaction for 4 hours to ensure that the hydrophilic groups of ethylene oxide and propylene oxide are successfully grafted onto the siloxane molecules to form a preliminary modified siloxane substrate.

[0053] S3: Add 15 parts by weight of titanium dioxide nanoparticles to the preliminarily modified silicone substrate. The titanium dioxide particles have a particle size of 30 nm and are subjected to ultrasonic dispersion treatment (ultrasonication time is 15 minutes) before addition to ensure uniform distribution of the nanoparticles in the solution.

[0054] S4: The mixed system is heated to 100°C and reacted at a stirring speed of 600 rpm for 4 hours. Titanium dioxide is wrapped by the core-shell structure of the surfactant to form nanomicelles with uniform particle size distribution, thereby significantly improving the solubilization and dispersion performance of the surfactant.

[0055] S5: After the reaction is completed, the mixture is cooled to room temperature, and 200 parts by weight of acetone is added to wash the reaction product to remove unreacted residual substances. The washed product is freeze-dried (the drying temperature is controlled at -20°C) to finally obtain an organosilicon-based surfactant with a particle size distribution in the range of 50 to 100 nm.

[0056] Example 2: Preparation of surfactant

[0057] The preparation method is basically the same as that of Example 1, except that the total mass of the mixture of ethylene oxide (EO) and propylene oxide (PO) is changed to 40 parts by weight of the mass of siloxane.

[0058] Example 3: Preparation of surfactant

[0059] The preparation method is basically the same as that of Example 1, except that the amount of titanium oxide nanoparticles used is changed to 10 parts by weight of the siloxane base.

[0060] Example 4: Preparation of surfactant

[0061] The preparation method is basically the same as that in Example 1, except that the amount of acetone is changed to 150 parts by weight.

[0062] Now the organosilicon-based surfactants prepared in Examples 1-4 are respectively applied to the pesticide technical, and the application process and application results thereof refer to Experimental Examples 1-3.

[0063] Experimental Example 1: Application of surfactants in glyphosate preparations

[0064] 60 parts by weight of glyphosate technical (a poorly water-soluble pesticide technical) were weighed, and 5 parts by weight of the surfactant prepared in Example 1 were prepared. At the same time, 200 parts by weight of deionized water were weighed as a solvent to ensure that the raw materials met the formulation design requirements.

[0065] Add glyphosate technical and surfactant into the reactor according to the formula ratio, and stir at 500 rpm for 10 minutes to allow the surfactant to fully contact with the glyphosate particles and begin to disperse.

[0066] Deionized water was slowly added, the stirring speed was controlled at 600 rpm, and the temperature was gradually raised to 50°C. Stirring was continued for 20 minutes to allow the surfactant to wrap the glyphosate particles, forming a uniform and stable dispersion system and significantly improving the water solubility of glyphosate.

[0067] The performance of the resulting glyphosate liquid preparation was tested, and the results showed that its surface tension was reduced to 18 mN / m, which is much lower than the surface tension of ordinary aqueous preparations; at the same time, the solubility of glyphosate was increased by 3 times compared with the system without adding surfactant.

[0068] The prepared glyphosate liquid preparation was diluted to a 20% effective concentration and sprayed on the surface of weed leaves. The experimental results showed that the spreadability of the glyphosate preparation on the leaf surface was significantly enhanced, the efficacy was increased by about 30%, and the amount of glyphosate used was reduced by 20% compared with ordinary preparations, with higher pesticide utilization efficiency.

[0069] It should be noted that by adding the surfactant prepared in Example 1, the solubility of the glyphosate preparation was increased to 3 times of the original, the particle size distribution was uniformly 10 to 100 nm, the surface tension was reduced to 18 mN / m, the efficacy was increased by about 30%, and the dosage was reduced by about 20%.

[0070] Example 2: The solubility of glyphosate was increased to 3.5 times of the original value, the particle size distribution was slightly increased to 15-110 nm, the surface tension was reduced to 17.8 mN / m, the particle encapsulation effect was further enhanced, and the efficacy was increased to 32%.

[0071] Example 3: The solubility of glyphosate is increased to 2.8 times of the original value, the particle size distribution is reduced to 10-90 nm, the surface tension is reduced to 18.5 mN / m, the dispersion system is more stable, but the efficacy is slightly reduced to 28%, and the dosage is reduced by about 18%.

[0072] Example 4: After cleaning, the purity of the surfactant was slightly reduced, the solubility of glyphosate was increased to 3.2 times of the original, the particle size distribution was uniform at 12-100 nm, the surface tension was reduced to 18.2 mN / m, the efficacy was increased to 30%, and the dosage was reduced by 19%.

[0073] Further, the preparation of the common aqueous glyphosate preparation of Experimental Example 1 includes the following steps:

[0074] Weigh 60 parts by weight of glyphosate technical and prepare 200 parts by weight of deionized water as solvent, without adding co-solvent, to ensure that all raw materials in the formula meet the quality requirements. Glyphosate technical is a poorly water-soluble pesticide, which is directly dissolved to form a common aqueous solution.

[0075] Add the weighed glyphosate technical into the reactor, slowly add deionized water under stirring condition of 500rpm, and stir for about 10 minutes to promote full contact between glyphosate technical and water, so that it gradually disperses and dissolves. If the dissolution rate is slow, the reaction system can be appropriately heated to 40-50℃ to accelerate the dissolution of glyphosate.

[0076] After the dissolution is complete, check whether the liquid is completely clear and there are no undissolved solid particles remaining. Then, the prepared liquid is filtered to remove possible impurities to ensure that the preparation has a clear and transparent appearance.

[0077] The filtered preparation is the ordinary aqueous glyphosate, which can be directly packaged for pesticide formulation development or dilution and spraying. The appearance of the finished product should be uniform and transparent, without precipitation or insoluble particles.

[0078] Experimental Example 2: Application of surfactant in imidacloprid preparation, wherein Experimental Example 2 differs from Experimental Example 1 in that:

[0079] The raw material preparation is different: 50 parts by weight of imidacloprid technical drug is weighed instead of glyphosate technical drug; at the same time, the solvent is changed to a mixed solvent of 100 parts by weight of deionized water and 30 parts by weight of ethanol.

[0080] The addition of solvent is different from the dispersion: a water-ethanol mixed solvent is slowly added to the mixture, the system is heated to 60°C, and stirring is continued for 30 minutes to ensure uniform dispersion of imidacloprid.

[0081] Differences in performance testing: The particle size distribution of the imidacloprid preparation is between 30 and 80 nm, the surface tension is reduced to 19 mN / m, and the suspension has excellent storage stability without sedimentation.

[0082] Different application effects: The suspension was diluted to an effective concentration of 10% (20% for glyphosate) and sprayed on the surface of rice leaves; the results showed that the efficacy of imidacloprid was increased by 25% (30% for glyphosate), while the dosage was reduced by about 15%.

[0083] It should be noted that by adding the surfactant prepared in Example 1, the particle size distribution of the imidacloprid preparation is uniformly 30-80 nm, the surface tension is reduced to 19 mN / m, the efficacy is increased by 25%, and the dosage is reduced by about 15%.

[0084] Example 2: The particle size distribution of imidacloprid slightly increased to 35-90 nm, the surface tension decreased to 18.7 mN / m, the efficacy increased to 28%, and the dosage was reduced by about 17%.

[0085] Example 3: The particle size distribution is reduced to 25-70 nm, the surface tension is reduced to 19.3 mN / m, the efficacy is slightly reduced to 23%, the dosage is reduced by 13%, and the storage stability of the preparation remains excellent.

[0086] Example 4: The particle size distribution of imidacloprid was maintained at 30-80 nm, the surface tension was reduced to 19.1 mN / m, the efficacy was increased to 26%, and the dosage was reduced by about 16%.

[0087] Further, the preparation method of the common aqueous solution of imidacloprid in Experimental Example 2 comprises the following steps:

[0088] Weigh 50 parts by weight of imidacloprid technical drug, and prepare 100 parts by weight of deionized water and 30 parts by weight of ethanol as a mixed solvent. Imidacloprid is a poorly water-soluble insecticide technical drug, and the solubilizing effect of ethanol is required to improve the dissolution efficiency.

[0089] The weighed imidacloprid original drug was added to the reactor, and 30 parts by weight of ethanol was slowly added first, and stirred at a stirring speed of 500 rpm for about 10 minutes to partially dissolve the imidacloprid in the ethanol. Then 100 parts by weight of deionized water was slowly added, and the reaction system was heated to 50-60°C, and stirring was continued for 30 minutes until the imidacloprid was completely dissolved.

[0090] After dissolution is complete, check whether the preparation forms a clear and transparent liquid without residual solid particles or impurities. Subsequently, the solution is passed through a filtration device to remove a small amount of insoluble impurities that may exist to ensure the uniformity and stability of the product.

[0091] The filtered liquid is the common aqueous solution of imidacloprid, which can be directly packaged or further diluted for use. The appearance of the preparation should be clear and transparent, dissolve well and have excellent storage stability.

[0092] Experimental Example 3: Application of surfactant in carbendazim preparation, wherein the difference between Experimental Example 4 and Experimental Example 3 is:

[0093] The raw material preparation is different: 40 parts by weight of carbendazim technical drug is weighed instead of glyphosate or imidacloprid; the solvent is 150 parts by weight of deionized water.

[0094] The addition of solvent is different from dispersion: deionized water was slowly added, the system was heated to 55°C, the stirring speed was increased to 700 rpm, and stirring was continued for 25 minutes to ensure full dissolution and uniform dispersion of carbendazim.

[0095] Differences in performance testing: The particle size distribution of carbendazim preparations is 40-90nm (narrower than 10-100nm of glyphosate), and the surface tension is reduced to 20mN / m (slightly higher than glyphosate and imidacloprid preparations). The suspension has good fluidity and uniformity.

[0096] Different application effects: The preparation was diluted to an effective concentration of 15% (20% for glyphosate and 10% for imidacloprid) and sprayed on the surface of fruit tree leaves. The results showed that the efficacy of carbendazim was increased by 20%, while the dosage of the agent was reduced by about 18%, and the control effect was significantly improved.

[0097] It should be noted that by adding the surfactant prepared in Example 1, the particle size distribution of the carbendazim preparation is uniformly 40-90 nm, the surface tension is reduced to 20 mN / m, the efficacy is improved by about 20%, and the dosage is reduced by about 18%.

[0098] Example 2 (the total mass of EO / PO was changed to 40 parts by weight): the particle size distribution of carbendazim was slightly increased to 45-100 nm, the surface tension was reduced to 19.8 mN / m, the efficacy was increased to 22%, and the dosage was reduced by about 19%.

[0099] Example 3 (the amount of titanium dioxide was changed to 10 parts by weight): the particle size distribution was reduced to 35-80 nm, the surface tension was reduced to 20.2 mN / m, the efficacy was slightly reduced to 18%, the dosage was reduced by about 16%, and the uniformity and fluidity of the preparation were maintained well.

[0100] Example 4 (the amount of acetone was changed to 150 parts by weight): the particle size distribution of carbendazim was maintained at 40-90 nm, the surface tension was reduced to 19.9 mN / m, the efficacy was increased to 21%, and the dosage was reduced by about 18.5%.

[0101] Further, the preparation method of the common aqueous preparation of carbendazim in Experimental Example 3 comprises the following steps:

[0102] Weigh 40 parts by weight of carbendazim technical drug and prepare 150 parts by weight of deionized water as a solvent without adding a solvent. Carbendazim is a poorly soluble fungicide technical drug, and its dissolution needs to be promoted by increasing the temperature and stirring at a high speed.

[0103] The weighed carbendazim technical drug was added into the reactor, and 150 parts by weight of deionized water was slowly added under high-speed stirring at 700 rpm, while the system was heated to 55° C. Stirring and heating were performed for about 25 minutes to ensure that the carbendazim was fully dissolved and evenly distributed in the solution.

[0104] After dissolution is complete, check whether the liquid is clear and transparent, without undissolved particles or precipitation. Then, the solution is finely filtered through a filtration device to remove possible impurity particles or trace insoluble matter.

[0105] The filtered preparation is the common aqueous solution of carbendazim, which is suitable for direct use or further dilution. The finished product should be clear and transparent without any precipitation or unevenness, and have good fluidity and uniformity.

[0106] The key to achieving the solubilization effect in Experimental Examples 1-3 is that the surfactant forms an amphiphilic structure by grafting hydrophilic groups (ethylene oxide EO and propylene oxide PO) on the siloxane molecules, so that it self-assembles into a core-shell structure nano-micelle in the solution. The hydrophobic core of the micelle can encapsulate the poorly soluble pesticide original drug molecules (such as glyphosate, imidacloprid or carbendazim), thereby significantly improving the solubility of the original drug; at the same time, titanium dioxide nanoparticles as a stable structure in the core enhance the dispersibility and anti-agglomeration ability of the micelles, making the particle size distribution of the preparation uniform, and finally achieving efficient solubilization of the original drug by reducing the surface tension (to below 20mN / m) and enhancing the solubility.

[0107] The present invention is not limited to the above-mentioned embodiments. Anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention. The technology, shape, and structural parts not described in detail in the present invention are all well-known technologies.

Claims

1. A method for preparing a surfactant, characterized in that: The following steps are involved: S1: 100 parts by weight of polymethyl hydrogen siloxane is dissolved in 50 to 150 parts by weight of ethanol to form a uniform siloxane base solution; S2: adding ethylene oxide and propylene oxide to the siloxane substrate solution, and reacting them under the action of a platinum-based catalyst so that the hydrophilic groups are combined with the siloxane molecules to form a preliminarily modified siloxane substrate; S3: adding titanium dioxide nanoparticles to the preliminarily modified siloxane substrate; S4: transferring the mixed system into a reaction kettle, stirring it fully, and controlling the reaction temperature at 80-120° C. for 2-6 hours to finally form nanomicelles with a core-shell structure; S5: Cooling the mixture after the reaction to room temperature, washing the reaction product by adding acetone to remove unreacted residual substances, and then removing the solvent by freeze drying to finally obtain a surfactant.

2. The method for preparing a surfactant according to claim 1, characterized in that: In step S2, the amount of the platinum-based catalyst used is 0.01% to 1% of the mass of the polymethylhydrogensiloxane.

3. The method for preparing a surfactant according to claim 1, characterized in that: The total weight of EO and PO in step S2 is 10-50 parts by weight, wherein the molar ratio of EO to PO is 1-5:

1.

4. The method for preparing a surfactant according to claim 1, characterized in that: In step S2, the reaction is carried out under the action of a platinum-based catalyst by stirring at 80-120° C. for 2 to 6 hours.

5. The method for preparing a surfactant according to claim 1, characterized in that: The metal oxide nanoparticles in step S3 are subjected to ultrasonic dispersion treatment before being added, and the ultrasonic time is 10 to 30 minutes to ensure that the particles are evenly distributed in the reaction system.

6. The method for preparing a surfactant according to claim 1, characterized in that: In step S3, the amount of titanium dioxide added is 5-20 parts by weight of the siloxane base material, and the particle size of titanium dioxide is 10-50 nm.

7. The method for preparing a surfactant according to claim 1, characterized in that: The final particle size distribution of the surfactant in step S5 is 10-100 nm, and its surface tension can be reduced to below 20 mN / m.

8. The method for preparing a surfactant according to claim 1, characterized in that: In step S5, the freeze-drying temperature is controlled at -20°C to -40°C.

9. A surfactant, characterized in that The method is prepared by the method according to any one of claims 1 to 8.

10. Use of the surfactant according to claim 9 in solubilizing pesticide original medicine.