Amphiphilic titanium dioxide emulsifier, Pickering emulsion and preparation method of Pickering emulsion

Abstract

The invention discloses a preparation method of an amphiphilic titanium dioxide emulsifier, which comprises the following steps: simultaneously adding a hydrophilic surface treating agent (hydrophilic silane coupling agent) and a hydrophobic surface treating agent (hydrophobic silane, stearic acid and the like) into nano titanium dioxide powder, and carrying out solid-phase stirring and heating treatment to obtain the amphiphilic titanium dioxide emulsifier. The hydrophilic surface treating agent and the hydrophobic surface treating agent are subjected to hydrolytic condensation reaction on the surface of the nano titanium dioxide, and hydrophilic hydroxyl and hydrophobic alkyl are simultaneously introduced into the surface of the nano titanium dioxide, so that local distribution of the hydrophilic hydroxyl and the hydrophobic alkyl is realized; the nano titanium dioxide powder material has the characteristics of a surfactant, the operation steps are simple, no solvent is used, and no waste liquid is generated. In addition, the invention also provides a method for preparing the Pickering emulsion from the amphiphilic titanium dioxide emulsifier, and the very uniform and stable Pickering emulsion can be prepared only through simple shaking, stirring and other modes.

Description

Technical Field

[0001] The invention relates to the technical field of daily chemical materials, and in particular to an amphiphilic titanium dioxide emulsifier, a Pickering emulsion and a preparation method thereof. Background Art

[0002] Pickering emulsion refers to an emulsion obtained by using ultrafine solid particles as emulsifiers, also known as Pickering emulsion. Pickering emulsions are formed by using nano solid particles instead of traditional surfactants to stabilize the oil-water interface, which can avoid the skin irritation and safety issues caused by traditional surfactants, and have great application potential in food, medicine, cosmetics and personal care products.

[0003] Since the unmodified inorganic nano solid particles have poor dispersibility, are very easy to agglomerate and have a certain hydrophilicity, resulting in poor emulsification performance, therefore, it is often necessary to carry out surface modification on the inorganic nano solid particles, introducing some lipophilic groups or hydrophilic groups to obtain suitable wettability. The method of surface modification on inorganic nano solid particles in the prior art is relatively cumbersome, costly, and waste water, waste oil, etc. are produced during the modification process. In addition, in the process of preparing Pickering emulsions by the modified inorganic nano solid particles, the operation is cumbersome.

[0004] The invention patent with application number CN201410384865.2 discloses a preparation process of a UV controlled release medicinal ingredient and easy-to-clean Pickering emulsion sunscreen. First, a TiO2 stabilized Pickering emulsion is prepared by modification with alkyl silane. 2 Nanoparticle surfactants are added to the oil phase and then mixed with the water phase to emulsify the target oil-in-water (W / O) emulsion sunscreen. Nanoparticles have UV light response characteristics. After being exposed to sunlight for a period of time, the emulsion can be demulsified and separated to release the medicinal ingredients. The patent uses hydrogen peroxide and dodecyl trichlorosilane to prepare a hydrophilic group and a hydrophobic group to achieve the effect of TiO 2 The surface modification of nanoparticles is carried out in a solution, which will produce wastewater and waste oil. The reaction requires ultrasonic dispersers, UV irradiators and other equipment, and the production process is cumbersome and expensive. In addition, the prepared titanium dioxide surfactant needs to be dispersed at a high speed to prepare the Pickering emulsion, and the operation process is complicated and cumbersome.

[0005] The invention patent with application number CN201910001998.X discloses an amphiphilic titanium dioxide emulsifier, a Pickering emulsion, and a preparation method and application thereof, comprising the following steps: S1, mixing a titanium salt precursor and a small molecule organic matter in an alcohol-water solution to form a titanium salt solution, and then hydrolyzing the titanium salt to obtain an amphiphilic TiO2 Nanoparticle sol is then dispersed, solvent, inhibitor and impurities are removed to obtain amphiphilic titanium dioxide emulsifier. In this step, small molecule organic matter is used as a surface hydrophilicity regulator to adjust the TiO 2 The surface is modified. S2. The aqueous solution of the amphiphilic titanium dioxide emulsifier is mixed with the oily raw material and homogenized to obtain a Pickering emulsion. In this patent, small molecule organic matter is used for surface modification in the process of preparing titanium dioxide nanoparticles. The above reaction is carried out in solution, and subsequent complex operations such as dispersion, removal of solvents, inhibitors and impurities are required. Summary of the invention

[0006] In order to solve the problems existing in the above-mentioned background technology, the present invention provides a method for preparing an amphiphilic titanium dioxide emulsifier, which achieves the localization and distribution of hydrophilic hydroxyl groups and hydrophobic alkyl groups on the surface of titanium dioxide nanoparticles through solid phase stirring and heating treatment, so that the nano titanium dioxide powder material has the characteristics of a surfactant, and the reaction process operation steps are simple, no solvent is used, and no waste liquid is generated. In addition, the present invention also provides a method for preparing a Pickering emulsion from an amphiphilic titanium dioxide emulsifier, which can prepare a very uniform and stable Pickering emulsion only by simple shaking, stirring, etc.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a method for preparing an amphiphilic titanium dioxide emulsifier, comprising the following steps:

[0009] S1. Add a hydrophilic surface treatment agent and a hydrophobic surface treatment agent to the nano titanium dioxide powder at the same time, stir the powder at a high speed of 2000-5000 rpm for 10 seconds, stir three times, stir well, and then heat the powder to form hydrophilic groups and hydrophobic groups on the surface of the nano titanium dioxide to obtain an amphiphilic titanium dioxide emulsifier.

[0010] The hydrophilic surface treatment agent is a hydrophilic silane coupling agent, including but not limited to: one or more of tetramethoxysilane, tetraethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane;

[0011] The hydrophobic surface treatment agent is a hydrophobic silane and / or a hydrophobic surface modifier, including but not limited to: one or more of triethoxyoctylsilane, isopropyl titanium triisostearate, polymethylsiloxane, and stearic acid.

[0012] Preferably, the particle size of the nano titanium dioxide is 30 to 300 nm.

[0013] Furthermore, the mass ratio of the hydrophilic surface treatment agent to the hydrophobic surface treatment agent is 1 / 4 to 4 / 1.

[0014] Preferably, the mass ratio of the hydrophilic surface treatment agent to the hydrophobic surface treatment agent is 1 / 3 to 3 / 1.

[0015] Specifically, by adjusting the dosage of the hydrophilic surface treatment agent and the hydrophobic surface treatment agent, the hydrophilicity and lipophilicity of the amphiphilic titanium dioxide emulsifier can be adjusted, and then an oil-in-water or water-in-oil Pickering emulsion can be prepared; in addition, by adjusting the dosage of the hydrophilic surface treatment agent and the hydrophobic surface treatment agent, the particle size of the water droplets or oil droplets in the Pickering emulsion can be controlled, and different types of cosmetics can be developed in combination with the usage scenarios.

[0016] Furthermore, the amphiphilic titanium dioxide emulsifier comprises the following raw materials in parts by weight: 70 to 90 parts of nano titanium dioxide powder, and 10 to 30 parts in total of a hydrophilic surface treatment agent and a hydrophobic surface treatment agent.

[0017] Preferably, the sum of the hydrophilic surface treatment agent and the hydrophobic surface treatment agent is 15 to 25 parts.

[0018] Furthermore, in the step S1, the heating process is specifically as follows: the powder material after being stirred and mixed evenly is placed in an oven at 100-150° C. and heated for 2-5 hours.

[0019] Through heat treatment, the hydrophilic surface treatment agent (hydrophilic silane coupling agent) and the hydrophobic surface treatment agent (hydrophobic silane, stearic acid, etc.) undergo hydrolysis and condensation reaction on the surface of nano-titanium dioxide, and the hydrophilic hydroxyl group and the hydrophobic alkyl group are simultaneously introduced into the surface of the nano-titanium dioxide, thereby achieving the localized distribution of the hydrophilic hydroxyl group and the hydrophobic alkyl group, and making the nano-titanium dioxide powder material have the characteristics of a surfactant.

[0020] The second aspect of the present invention provides a method for preparing a Pickering emulsion, comprising the steps of preparing the above-mentioned amphiphilic titanium dioxide emulsifier, and further comprising the following steps:

[0021] S2. Add the amphiphilic titanium dioxide emulsifier into a container containing a mixed solution of water and oil, and prepare a Pickering emulsion by simply shaking or stirring the container.

[0022] The content of the amphiphilic titanium dioxide emulsifier in the Pickering emulsion is 0.05-10 wt %.

[0023] The Pickering emulsion prepared in the present invention is very uniform and stable, and can play a huge role in many fields such as cosmetics, food industry, biomedicine, and petroleum industry, and is expected to overcome the problem of demulsification of cosmetic emulsions when placed for a long time.

[0024] Furthermore, in step S2, the mass ratio of oil to water is 1 / 9 to 9 / 1.

[0025] Furthermore, the oil includes mineral oil, silicone oil or grease.

[0026] Specifically, the oils used in Pickering emulsion include, but are not limited to, stearic acid ester, cetyl ethylhexanoate, isononyl isononanoate, isododecane, octyldodecanol stearyloxystearate, polydimethylsiloxane, cyclopentasiloxane, and the like.

[0027] The third aspect of the present invention provides an amphiphilic titanium dioxide emulsifier, which is prepared by the preparation method of the amphiphilic titanium dioxide emulsifier.

[0028] A fourth aspect of the present invention provides a Pickering emulsion prepared by the above-mentioned method for preparing the Pickering emulsion.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] In the present invention, a hydrophilic surface treatment agent (hydrophilic silane coupling agent) and a hydrophobic surface treatment agent (hydrophobic silane, stearic acid, etc.) are simultaneously added to nano titanium dioxide powder, and through solid phase stirring and heating treatment, the hydrophilic surface treatment agent and the hydrophobic surface treatment agent undergo hydrolysis and condensation reactions on the surface of the nano titanium dioxide, and hydrophilic hydroxyl groups and hydrophobic alkyl groups are simultaneously introduced into the surface of the nano titanium dioxide, thereby achieving localized distribution of the hydrophilic hydroxyl groups and the hydrophobic alkyl groups, so that the nano titanium dioxide powder material has the characteristics of a surfactant, and the reaction process has simple operation steps, does not use solvents, and does not generate waste liquid.

[0031] The process of preparing Pickering emulsion using the amphiphilic titanium dioxide emulsifier is simple to operate. A very uniform and stable Pickering emulsion can be prepared by simple shaking, stirring, etc., which is expected to overcome the problem of demulsification of cosmetic emulsions after long-term storage. Pickering emulsions can play a huge role in many fields such as cosmetics, food industry, biomedicine, and petroleum industry.

[0032] In addition, by adjusting the amount of hydrophilic surface treatment agent (hydrophilic silane coupling agent) and hydrophobic surface treatment agent (hydrophobic silane, stearic acid, etc.), the formation of water-in-oil or oil-in-water Pickering emulsion can be controlled, and the particle size of water droplets or oil droplets in the Pickering emulsion can be controlled. Different types of cosmetics can be developed based on the usage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Figure 1 This is a real picture of water being dropped on the amphiphilic titanium dioxide emulsifier powder prepared in Example 1;

[0035] Figure 2 A physical picture of the Pickering emulsion prepared in Example 1 (left), and a physical picture of the oil-water mixed solution without adding the amphiphilic titanium dioxide emulsifier prepared in Example 1 (right);

[0036] Figure 3 The following are photos of the Pickering emulsion prepared in Example 1 before and after being placed at room temperature for two months. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] A Pickering emulsion, the preparation process of which is as follows:

[0040] S1, add 80g of nano titanium dioxide powder, 10g of hydrophilic surface treatment agent (tetraethoxysilane), and 10g of hydrophobic surface treatment agent (triethoxyoctylsilane) into a high-speed grinder, stir at a speed of 4000rpm for 10s, stir three times, stir well, and obtain a mixed material;

[0041] S2, placing the mixed material in a drying oven and heating it at 120° C. for 3 h to obtain an amphiphilic titanium dioxide emulsifier, wherein hydrophilic groups and hydrophobic groups are introduced on the surface of the nano-titanium dioxide;

[0042] S3. Add 200 mg of the prepared amphiphilic titanium dioxide emulsifier into a container containing 5 mL of a mixed solution of water and 5 mL of oil (isododecane), and shake the container briefly to prepare a Pickering emulsion.

[0043] The amphiphilic titanium dioxide emulsifier prepared in this example exhibits excellent emulsification properties. The Pickering emulsion prepared does not have any precipitation or demulsification after being placed at room temperature for one month, indicating that the emulsion has excellent stability.

[0044] Depend on Figure 1 It can be seen that the amphiphilic titanium dioxide emulsifier prepared in this example exhibits good hydrophilicity. When water is dropped on the prepared amphiphilic titanium dioxide emulsifier powder, the powder is evenly wrapped on the surface of the water droplet to prevent the water droplet from spreading.

[0045] Depend on Figure 2 As can be seen from the left picture, the Pickering emulsion prepared in this embodiment is milky white and has no water-oil separation. Figure 2 The picture on the right side is a real picture of the oil-water mixed solution without adding amphiphilic titanium dioxide emulsifier. The water and oil are separated and a uniform emulsion cannot be formed.

[0046] Depend on Figure 3 It can be seen that after the Pickering emulsion prepared in this example was placed at room temperature for two months, there was no precipitation or demulsification phenomenon, which shows that the emulsion has excellent stability.

[0047] Example 2

[0048] A Pickering emulsion, the preparation process of which is as follows:

[0049] S1, adding 90g of nano titanium dioxide powder, 5g of hydrophilic surface treatment agent (tetraethoxysilane), and 5g of hydrophobic surface treatment agent (triethoxyoctylsilane) into a high-speed grinder, stirring at a speed of 4000rpm for 10s, stirring three times, stirring evenly, and obtaining a mixed material;

[0050] S2, placing the mixed material in a drying oven and heating it at 120° C. for 3 h to obtain an amphiphilic titanium dioxide emulsifier, wherein hydrophilic groups and hydrophobic groups are introduced on the surface of the nano-titanium dioxide;

[0051] S3. Add 200 mg of the prepared amphiphilic titanium dioxide emulsifier into a container containing 2 mL of water and 8 mL of oil (isododecane) mixed solution, and shake the container briefly to prepare a Pickering emulsion.

[0052] The amphiphilic titanium dioxide emulsifier prepared in this example exhibits better lipophilic properties and can be used to prepare water-in-oil Pickering emulsions.

[0053] Example 3

[0054] A Pickering emulsion, the preparation process of which is as follows:

[0055] S1, add 70g of nano titanium dioxide powder, 24g of hydrophilic surface treatment agent (tetraethoxysilane), and 6g of hydrophobic surface treatment agent (triethoxyoctylsilane) into a high-speed grinder, stir at a speed of 4000rpm for 10s, stir three times, stir well, and obtain a mixed material;

[0056] S2, placing the mixed material in a drying oven and heating it at 120° C. for 3 h to obtain an amphiphilic titanium dioxide emulsifier, wherein hydrophilic groups and hydrophobic groups are introduced on the surface of the nano-titanium dioxide;

[0057] S3. Add 200 mg of the prepared amphiphilic titanium dioxide emulsifier into a container containing 9 mL of water and 1 mL of oil (isododecane) mixed solution, and shake the container briefly to prepare a Pickering emulsion.

[0058] The amphiphilic titanium dioxide emulsifier prepared in this example exhibits better hydrophilic properties, and an oil-in-water Pickering emulsion is prepared.

[0059] Example 4

[0060] A Pickering emulsion, the preparation process of which is as follows:

[0061] S1, add 70g of nano titanium dioxide powder, 6g of hydrophilic surface treatment agent (tetraethoxysilane), and 24g of hydrophobic surface treatment agent (triethoxyoctylsilane) into a high-speed grinder, stir at a speed of 4000rpm for 10s, stir three times, stir well, and obtain a mixed material;

[0062] S2, placing the mixed material in a drying oven and heating it at 120° C. for 3 h to obtain an amphiphilic titanium dioxide emulsifier, wherein hydrophilic groups and hydrophobic groups are introduced on the surface of the nano-titanium dioxide;

[0063] S3. Add 500 mg of the prepared amphiphilic titanium dioxide emulsifier into a container containing 3 mL of water and 7 mL of oil (isododecane) mixed solution, and shake the container briefly to prepare a Pickering emulsion.

[0064] The amphiphilic titanium dioxide emulsifier prepared in this example has good lipophilicity and can be used to prepare water-in-oil Pickering emulsion.

[0065] Example 5

[0066] A Pickering emulsion, the preparation process of which is as follows:

[0067] S1, add 85g of nano titanium dioxide powder, 3.75g of hydrophilic surface treatment agent (tetramethoxysilane), and 11.25g of hydrophobic surface treatment agent (stearic acid) into a high-speed grinder, stir at a speed of 4000rpm for 10s, stir three times, stir well, and obtain a mixed material;

[0068] S2, placing the mixed material in a drying oven and heating it at 120° C. for 3 h to obtain an amphiphilic titanium dioxide emulsifier, wherein hydrophilic groups and hydrophobic groups are introduced on the surface of the nano-titanium dioxide;

[0069] S3. Add 500 mg of the prepared amphiphilic titanium dioxide emulsifier into a container containing 3 mL of water and 7 mL of oil (isododecane) mixed solution, and shake the container briefly to prepare a Pickering emulsion.

[0070] The amphiphilic titanium dioxide emulsifier prepared in this example exhibits better lipophilicity and produces a milky white water-in-oil Pickering emulsion.

[0071] Example 6

[0072] A Pickering emulsion, the preparation process of which is as follows:

[0073] S1, add 75g of nano titanium dioxide powder, 18.75g of hydrophilic surface treatment agent (tetramethoxysilane), and 6.25g of hydrophobic surface treatment agent (stearic acid) into a high-speed grinder, stir at a speed of 4000rpm for 10s, stir three times, stir well, and obtain a mixed material;

[0074] S2, placing the mixed material in a drying oven and heating it at 120° C. for 3 h to obtain an amphiphilic titanium dioxide emulsifier, wherein hydrophilic groups and hydrophobic groups are introduced on the surface of the nano-titanium dioxide;

[0075] S3. Add 500 mg of the prepared amphiphilic titanium dioxide emulsifier into a container containing 3 mL of water and 7 mL of oil (isododecane) mixed solution, and shake the container briefly to prepare a Pickering emulsion.

[0076] The amphiphilic titanium dioxide emulsifier prepared in this example exhibits better hydrophilicity, and a milky white oil-in-water Pickering emulsion is prepared.

[0077] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an amphiphilic titanium dioxide emulsifier, characterized in that: The following steps are involved: S1, adding a hydrophilic surface treatment agent and a hydrophobic surface treatment agent to the nano titanium dioxide powder at the same time, stirring it fully with a high-speed pulverizer, and then heating it to form hydrophilic groups and hydrophobic groups on the surface of the nano titanium dioxide to obtain an amphiphilic titanium dioxide emulsifier; The hydrophilic surface treatment agent includes one or more of tetramethoxysilane, tetraethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane; The hydrophobic surface treatment agent includes one or more of triethoxyoctylsilane, isopropyl titanium triisostearate, polymethylsiloxane, and stearic acid.

2. The method for preparing the amphiphilic titanium dioxide emulsifier according to claim 1, characterized in that: The mass ratio of the hydrophilic surface treatment agent to the hydrophobic surface treatment agent is 1 / 4 to 4 / 1.

3. The method for preparing the amphiphilic titanium dioxide emulsifier according to claim 2, characterized in that: The amphiphilic titanium dioxide emulsifier comprises the following raw materials in parts by weight: 70 to 90 parts of nano titanium dioxide powder, and 10 to 30 parts in total of a hydrophilic surface treatment agent and a hydrophobic surface treatment agent.

4. The method for preparing the amphiphilic titanium dioxide emulsifier according to claim 1, characterized in that: In the step S1, the heating process is specifically as follows: the powder material after being stirred and mixed evenly is placed in an oven at 100-150° C. and heated for 2-5 hours.

5. A method for preparing a Pickering emulsion, characterized in that: The method comprises the steps of preparing the amphiphilic titanium dioxide emulsifier according to any one of claims 1 to 4, and further comprising the following steps: S2, adding the amphiphilic titanium dioxide emulsifier into a container containing a mixed solution of water and oil, and shaking the container to obtain a Pickering emulsion; The content of the amphiphilic titanium dioxide emulsifier in the Pickering emulsion is 0.05-10 wt %.

6. The method for preparing a Pickering emulsion according to claim 5, characterized in that: In step S2, the mass ratio of oil to water is 1 / 9 to 9 / 1.

7. The method for preparing a Pickering emulsion according to claim 5, characterized in that: The oil includes mineral oil, silicone oil or grease.

8. An amphiphilic titanium dioxide emulsifier, characterized in that It is prepared by the method according to any one of claims 1 to 4.

9. A Pickering emulsion, characterized in that It is prepared by the method according to any one of claims 5 to 7.

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