Self-repairing and self-lubricating difunctional microcapsules and preparation method thereof

Self-repairing and self-lubricating dual-function microcapsules and preparation method thereofTechnical field

[0001] The present invention belongs to the technical field of self-lubricating materials, and specifically relates to a dual-functional microcapsule, in particular to a self-lubricating and self-repairing dual-functional microcapsule and a preparation method thereof.

Background technique

[0002] Microencapsulation is the encapsulation of gas, liquid or solid materials in the form of capsules, with a particle size ranging from several hundred nanometers to several hundred microns. Microcapsule technology has been widely used as a high-tech industry in many fields such as medicine, food, chemical industry, electronics, and intelligent polymer materials. By microencapsulating the material, it can have a variety of functions, such as improving the lubricating performance of the material and giving the material self-repairing function. The microcapsule containing liquid lubricant (lubricant, ionic liquid, etc.) is compounded with the matrix. When the friction process is triggered, the liquid lubricant will be released from the microcapsule to the interface, thereby effectively improving the tribological properties of the polymer composite. The microcapsules containing the repairing agent are embedded in the polymer matrix. When the polymer matrix is damaged, the microcapsules rupture and the repairing agent is released, and the corresponding repairing effect occurs in the damaged area to reach the damaged area of the material. The purpose of the repair. At present, the use of polymer or inorganic materials to coat lubricants or repairing agents to prepare microcapsules and their composite materials has been very extensive, and many research results have been obtained. However, the research on the integration of microcapsule self-lubrication and self-repairing functions is still The initial stage.

Summary of the invention

[0003] Based on the application of microcapsules in the field of self-lubricating materials, the present invention integrates two functions to prepare dual-function microcapsules containing both repairing agent and lubricant, so that the microcapsule composite material has lubricating properties and wear self-repairing functions . The specific technical scheme of the present invention is as follows.

[0004] A self-healing and self-lubricating dual-function microcapsule, the microcapsule has two structural forms, one is a single-layer core-shell structure, the other is a multilayer composite structure; the core-shell structure The core is the core material, and also contains repairing agent and lubricant; the shell is the wall material. The repairing agent is one or more of dibutyl phthalate, triethylenetetramine, ethyl phenylacetate, dicyclopentadiene, isophorone diisocyanate, and hexamethylene diisocyanate; lubricant It is one or more of base oil, synthetic oil, vegetable oil, and oil-soluble ionic liquid; the mass ratio of repair agent and lubricant is 0.1-10; the mass fraction of microcapsule core material is 30%-80%. The wall materials of the microcapsules are organic (urea-formaldehyde resin, polystyrene, polymethyl methacrylate) or organic-inorganic (nano clay, titanium dioxide, silicon dioxide, graphene oxide, black phosphorus) hybrids.

[0005] A self-repairing and self-lubricating dual-function microcapsule, there are two structures, one is a single-layer core-shell structure, and the other is a multilayer composite structure.

[0006] The preparation methods of the single-layer core-shell structure microcapsules are prepared by emulsion polymerization, Pickering emulsion, emulsion polymerization, or solvent volatilization:

[0007] (1) Emulsion polymerization method: first add a certain amount of lubricant and repair agent mixture and the monomer (precursor) solution of the wall material into deionized water containing surfactants, and form a stable solution under the action of ultrasound or stirring. The emulsion is reacted for several hours under certain conditions, filtered, washed, and dried to obtain single-layer core-shell microcapsules.

[0008] (2) Combined use of Pickering emulsion method and emulsion polymerization method: adding a certain quality of modified inorganic nanoparticles to deionized water for ultrasonic dispersion to form a uniformly dispersed nanoparticle dispersion, and a certain amount of lubrication Agent, repair agent, polymer

The monomer (precursor) and initiator (catalyst) mixture is added to the nanoparticle dispersion, emulsified by a high-speed emulsifier to form a Pickering emulsion, and then reacted under certain conditions to obtain an organic-inorganic hybrid shell monolayer core Shell structure microcapsules.

[0009] (3) The combined preparation process of Pickering emulsion method and solvent volatilization method is: adding a certain mass of modified inorganic nanoparticles to deionized water for ultrasonic dispersion to form a uniformly dispersed nanoparticle dispersion, and a certain amount of Lubricants, repair agents, polymers, dissolved in organic solvents, fully dissolved and mixed, and then added to the nanoparticle dispersion, emulsified by a high-speed emulsifier to form a Pickering emulsion, and then reacted under certain conditions to obtain an organic-inorganic hybrid Shell single-layer microcapsules.

[0010] Multi-layer composite structure microcapsules, the preparation process is: first, the repair agent (or lubricant) is used as the core material to prepare single-layer core-shell structure microcapsules (the method is the same as above), and then the lubricant (or repair agent) is adsorbed On the surface of the microcapsule, a multi-layer composite structure microcapsule is prepared by solvent volatilization method or emulsion polymerization method.

[0011] Compared with the prior art, the present invention has the following outstanding effects: it breaks through the single function defect of the traditional microcapsule composite material, and realizes the multifunctionalization of the self-lubricating capsule. The dual-function microcapsule of the present invention not only has good lubricating performance, but also has the characteristics of self-repairing wear scars. This multifunctional design can greatly increase the service life of the microcapsule self-lubricating composite material, and has broad application prospects in aerospace, marine engineering and other fields.

Description of the drawings

[0012] FIG. 1 is a physical diagram of microcapsules coated with urea-formaldehyde resin dibutyl phthalate (DBP) and PAO6.

[0013] Figure 2 is a SEM image of urea-formaldehyde resin coated dibutyl phthalate (DBP) and PAO6 microcapsules.

[0014] FIG. 3 is a schematic diagram of the structure of the self-lubricating and self-repairing dual-function microcapsules of the present invention.

Detailed ways

[0015] The present invention will be further described in detail below with reference to the drawings and embodiments.

Example 1

[0017] Single-layer core-shell microcapsules: in a three-necked round-bottom flask (1L) equipped with a mechanical stirring blade, add 250mL of a surfactant aqueous solution system (0.2wt.%SDBS, 0.1wt.%PVA-124). Place the flask in a 35°C water bath with constant stirring. Add urea, resorcinol, ammonium chloride, adjust the pH to 3.5 with glacial acetic acid, add a mixture of 6g DBP and 6g PAO6, stabilize for 10 minutes, and form a stable oil-in-water microemulsion. After that, 6.4g of 37% formaldehyde solution was added, the temperature was raised to 55°C, and stirring was continued for 6h. After the reaction, the flask was taken out from the water bath and cooled to room temperature, washed, filtered, and dried at room temperature to obtain microcapsule particles. The product is shown in Figure 1. A small amount of the product was dispersed in deionized water to prepare a SEM sample for analysis The morphology of the product is shown in Figure 2.

Example 2

[0019] Single-layer core-shell structure microcapsules: 0.3g of modified nano-silica was added to 50ml of deionized water, ultrasonically dispersed for 10 minutes to obtain a nano-silica dispersion; the oil phase mixture (5g methyl methacrylate , 0.25g of azobisisobutyronitrile, 3g of triethylenetetramine and 1g of linseed oil) were added to the dispersion and emulsified at high speed for 3min to form a Pickering emulsion. Subsequently, the prepared emulsion was transferred to a 100ml three-necked flask, and the temperature was raised to 80C for 10h under the protection of N2. After the reaction, the flask was taken out of the water bath and cooled down to room temperature, washed, filtered, and dried at room temperature to obtain microcapsule particles.

Example 3

[0021] Multi-layer composite structure microcapsules: (1) Add 37% formaldehyde solution, urea, and melamine with a mass ratio of 13:5:1 into a 500mL three-necked flask with a condenser, and add triethanolamine dropwise to adjust the pH to 9. React at 70°C for 1 hour to prepare a prepolymer solution and cool it for later use. (2) In a three-necked round-bottom flask (1L) equipped with a mechanical stirring blade, add 250mL surface

The active agent aqueous solution system (0.5wt.% gum arabic, 0.1wt.% PVA-124) and 4g triethylenetetramine are stirred to obtain a stable emulsion. Add the prepolymer to the emulsion, stir and emulsify for 30 minutes, adjust the pH to 4 with glacial acetic acid, after the microcapsules are completely formed, the temperature is increased to 60°C, solidified for a certain period of time, and the resulting suspension is mixed with ethanol several times Single-layer microcapsules are obtained by washing and suction filtration for use. (3) Add a certain quality of polystyrene and castor oil to methylene chloride, and magnetically stir to fully dissolve and mix. Then add the microcapsules obtained in step (2), stir for 30min, add 250ml of surfactant aqueous solution system (0.5wt.% gum arabic, 0.2wt.% PVA-124), heat the water bath to 45°C and use 600r/min Stir at a high speed and react for a period of time until the dichloromethane is completely evaporated. The flask is taken out of the water bath and cooled to room temperature, washed, filtered, and dried at room temperature to obtain double-walled microcapsule particles.

Example 4

[0023] Multi-layer composite structure microcapsules: (1) Add 37% formaldehyde solution, urea, and melamine with a mass ratio of 13:5:1 into a 500mL three-necked flask with a condenser, and add triethanolamine dropwise to adjust the pH to 9. React at 70°C for 1 hour to prepare a prepolymer solution and cool it for later use. (2) In a three-necked round-bottom flask (1L) equipped with a mechanical stirring blade, add 250mL surfactant aqueous solution system (0.5wt.% gum arabic, 0.1wt.% PVA-124) and 6g phenyl ethyl acetate, and stir. A stable emulsion is obtained. The prepolymer was added to the emulsion, stirred and emulsified for 30 minutes, and then adjusted to pH 4 with glacial acetic acid. After the microcapsules were completely formed, the temperature was increased to 60C and solidified for a certain time to obtain a microcapsule suspension. (3) Add a certain quality of ionic liquid to the microcapsule suspension, and mix it thoroughly with magnetic stirring to make the surface of the microcapsule adsorb the ionic liquid. Then add the prepolymer obtained in step (1), stir and emulsify for 30 minutes, adjust the pH to 4 with glacial acetic acid, after the microcapsules are completely formed, the temperature is increased to 60C, and solidified for a certain period of time to obtain a microcapsule suspension. Take it out of the water bath, cool it down to room temperature, wash, filter, and dry at room temperature to obtain double-walled microcapsule particles.

[0024] The above embodiments describe the technical solutions of the present invention in detail. Obviously, the present invention is not limited to the described embodiments. Based on the embodiments of the present invention, those skilled in the art can make various changes accordingly, but any changes equivalent or similar to the present invention fall within the protection scope of the present invention.