CN114515553B

CN114515553B - Self-repairing self-lubricating difunctional microcapsule and preparation method and application thereof

Info

Publication number: CN114515553B
Application number: CN202210047985.8A
Authority: CN
Inventors: 李海燕; 李志科; 汪怀远; 李卡卡; 李鑫; 冯莹莹; 李新凯; 臧庆伟
Original assignee: Northeast Petroleum University
Current assignee: Northeast Petroleum University
Priority date: 2022-01-17
Filing date: 2022-01-17
Publication date: 2023-05-23
Anticipated expiration: 2042-01-17
Also published as: CN114515553A

Abstract

The invention relates to a novel self-repairing self-lubricating difunctional microcapsule, and a preparation method and application thereof. In particular, the present invention provides a method for preparing a dual-function microcapsule, comprising: impregnating the hollow porous microbeads with a self-repairing agent to obtain self-repairing agent-impregnated microbead capsules; uniformly mixing the self-lubricant in a molten state with the self-repairing agent impregnated microbead capsule to obtain a dual-function mixture; and spraying the difunctional mixture on a collecting plate, and collecting the cooled difunctional mixture from the collecting plate to obtain the difunctional microcapsule. The invention also provides the microcapsule prepared by the method, a method for preparing the self-repairing self-lubricating double-function composite material by using the microcapsule and the self-repairing self-lubricating double-function composite material prepared by the method. The invention has the advantages of green and environment protection, and can prepare the microcapsule or the composite material based on the microcapsule with excellent self-repairing and self-lubricating functions.

Description

Self-repairing self-lubricating difunctional microcapsule and preparation method and application thereof

Technical Field

The invention relates to the technical field of new materials, in particular to a novel self-repairing self-lubricating difunctional microcapsule, a preparation method and application thereof.

Background

Microcapsules are microparticles having a core-shell structure, whose cores (core materials) and shells (wall materials) can be designed according to different application requirements. In recent years, microcapsules have been widely used in the field of self-repairing and self-lubricating materials. The microcapsule is mainly applied to the field of self-repairing and is mainly used for preparing self-repairing polymer matrix composite materials, self-repairing anticorrosive coatings, self-repairing concrete and the like.

In the preparation process of the microcapsule, the repairing agent is used as a core material, and then an organic or inorganic material or an organic/inorganic hybrid material is used as a wall material, wherein the wall material has the main function of protecting the core material or enabling the microcapsule to have a slow release function. The microcapsule is embedded in the matrix material, when the matrix material is damaged or microcracks are generated, the microcapsule is broken, the released repairing agent fills the microcracks, a self-repairing film is formed at the microcracks, and the cracks are repaired, so that the self-repairing of the matrix material is realized.

The microcapsule is mainly applied to the field of self-lubrication to prepare a self-lubricating polymer matrix composite material, wherein a lubricant is used as a core material, and an organic or inorganic material or an organic/inorganic hybrid material is used as a wall material to prepare the microcapsule. The microcapsule is added into a composite material matrix, the microcapsule is broken under the action of friction and abrasion, and the released lubricant can form a self-lubricating transfer film on the friction surface, so that the friction and abrasion resistance of the material is effectively improved.

The wall materials commonly used in the microcapsules reported in the current literature are mainly organic wall materials, such as urea formaldehyde resin, melamine resin, polyurethane, polyurea, polysulfone, polystyrene and the like. When the organic matters are used as the wall material of the microcapsule, the microcapsule is generally synthesized by adopting chemical methods or physical and chemical methods such as in-situ polymerization, interfacial polymerization, solvent volatilization and the like. The use of multiple chemical reagents may be involved in the microencapsulation process. Inorganic wall materials such as silica or organic-inorganic hybrid wall materials such as polysulfone/silica, polystyrene/silica, etc. commonly used for microcapsules are also prepared by sol-gel method or other chemical methods in combination. The use of various chemical reagents is thus involved in the microencapsulation process, resulting in the production of microcapsules and microcapsule-based composites that are burdened with the environment, and thus there is a great urgent need for environmentally friendly microcapsules and microcapsule-based composites and methods for preparing them.

The invention develops an environment-friendly microencapsulation method, which does not use or uses trace chemical reagents in the preparation process of the microcapsule. Simultaneously, the self-repairing agent and the self-lubricating agent are respectively introduced into the core material and the wall material structure of the microcapsule, so that the prepared microcapsule has self-repairing and self-lubricating functions, and can be applied to a polymer matrix composite material matrix to prepare a polymer matrix composite material or coating with self-repairing and self-lubricating functions.

Disclosure of Invention

The invention provides a novel self-repairing self-lubricating difunctional microcapsule, a preparation method thereof and application thereof in polymer matrix composite materials. The microcapsule takes hollow porous glass beads as a carrier, and self-repairing agent (drying oil, isocyanate, epoxy resin and the like) is impregnated in the cavity of the microcapsule by a physical impregnation method to prepare the self-repairing agent@glass bead microcapsule; and then coating a phase change material (such as paraffin) on the outer surface of the glass microsphere impregnated with the self-repairing agent by adopting a phase change method, and finally preparing the self-repairing agent @ glass microsphere/self-lubricant double-wall microcapsule (shown in figure 1), wherein the phase change material wall layer not only encapsulates the porous structure on the surface of the glass microsphere so as to prevent leakage of the core material repairing agent, but also enables the microcapsule to have a self-lubricating function at the same time by taking the phase change material as a lubricant.

In particular, the present invention provides in a first aspect a method of preparing a self-repairing self-lubricating bi-functional microcapsule, the method comprising the steps of:

(1) Impregnating the hollow porous microbeads with a self-repairing agent to obtain self-repairing agent-impregnated microbead capsules;

(2) Uniformly mixing the self-lubricant in a molten state with the self-repairing agent impregnated microbead capsule to obtain a dual-function mixture;

(3) And spraying the difunctional mixture on a collecting plate, and collecting the cooled difunctional mixture from the collecting plate to obtain the difunctional microcapsule.

The present invention provides in a second aspect a self-repairing, self-lubricating, bi-functional microcapsule made according to the method of the first aspect of the invention.

The present invention provides in a third aspect a method of preparing a self-repairing, self-lubricating, bi-functional composite material, the method comprising:

(1) Preparing a resin matrix mixture comprising a resin matrix, a curing agent, and a solvent;

(2) Spraying the dual-function microcapsules into the resin matrix mixture while stirring the resin matrix mixture, and uniformly dispersing to prepare a resin mixture;

(3) And curing the resin mixture to obtain the self-repairing self-lubricating dual-function composite material.

The present invention provides in a fourth aspect a self-repairing, self-lubricating, bi-functional composite material made according to the method of the third aspect of the present invention.

Compared with the prior art, the invention has the following beneficial technical effects:

(1) In the microencapsulation process, the preparation of the porous glass beads adopts a subcritical water treatment method, and the whole process is carried out in water or only a small amount of sodium hydroxide is added; the invention adopts a physical impregnation method in the preparation process of the self-repairing agent@microbead microcapsule, and does not involve the use of chemical reagents, so that compared with the self-repairing or self-lubricating microcapsule reported in the current literature, the microcapsule preparation method is environment-friendly.

(2) In the preparation process of the self-repairing agent @ glass bead/phase change material double-wall microcapsule, a phase transformation method is adopted to carry out microcapsule coating in a molten state of the phase change material, and after cooling, the phase change material is changed from a liquid phase to a solid phase, so that a glass bead/phase change material double-wall layer structure can be finally formed. Compared with the self-repairing or self-lubricating microcapsule reported in the current literature, the microcapsule core material prepared by the microcapsule preparation method has a self-repairing effect, and the wall material has a self-lubricating effect, so that the application of the dual-function composite material or coating can be satisfied.

(3) The polymer matrix composite or coating containing the microcapsule prepared by the invention shows excellent self-repairing and self-lubricating properties.

Drawings

FIG. 1 is a schematic diagram of the preparation process of the novel self-repairing self-lubricating difunctional microcapsule of the present invention

FIG. 2 shows SEM images of glass beads and microcapsules, wherein FIG. (a) shows an SEM image of glass beads; figure (b) shows an SEM image of porous glass microspheres; figure (c) shows SEM images of linseed oil @ glass beads/paraffin microcapsules.

FIG. 3 shows the corrosion of epoxy resin coatings (a-d: 0, 5, 10,15 wt.%) at scratches after 3.5. 3.5 wt% NaCl brine immersion (1-4: 1, 5, 10,15 days).

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The present invention provides in a first aspect a method of preparing a self-repairing self-lubricating bi-functional microcapsule, the method comprising the steps of:

In some preferred embodiments, the self-healing agent is one or more self-healing agents selected from the group consisting of drying oils, isocyanates, and epoxy resins.

In other preferred embodiments, the self-lubricant is a phase change material, preferably, the phase change material is paraffin wax in a solid state at room temperature, more preferably, the paraffin wax has a melting point of 45 to 70 ℃ (e.g., 50 or 60 ℃).

In other preferred embodiments, the hollow porous microbeads are spherical microbeads having an outer diameter of 5 to 200 microns and an inner diameter of 2 to 180 microns. Preferably, the hollow porous microbeads are hollow porous glass microbeads. More preferably, the hollow porous microbeads are prepared by the following method: and (3) placing the hollow glass beads into alkali liquor to obtain a hollow glass bead mixture, placing the hollow glass bead mixture into a reaction kettle, raising the temperature to 150-300 ℃ (e.g. 200 or 250 ℃), raising the pressure in the reaction kettle to 0.5-9 MPa (e.g. 1, 2 or 5 MPa), maintaining the temperature for 1-3 hours (e.g. 2 hours), and then cooling to room temperature to obtain the hollow porous glass beads. It is further preferred that the lye is an aqueous sodium hydroxide or potassium hydroxide solution at a concentration of 0.1 to 1M (e.g. 0.5M). Of course, if water is used instead of the lye, a porous structure can be obtained. However, from the viewpoint of productivity and the like, it is preferable to use an alkali solution instead of pure water.

In other preferred embodiments, step (1) is performed by: adding the hollow porous microbeads into a self-repairing agent, dispersing uniformly, putting into a vacuum oven to remove bubbles in the hollow porous microbeads, enabling the self-repairing agent to be immersed into the hollow porous microbeads, standing for 3 to 24 hours (for example, 6, 9, 12, 15, 18 or 21 hours) at normal temperature, filtering and cleaning the obtained product, and obtaining the self-repairing agent-immersed microbead capsules. Preferably, the mass ratio of the hollow porous microbeads to the self-repairing agent is 1 (2-10), for example, 1: (3, 4, 5, 6, 7, 8 or 9). More preferably, the dispersion is performed by means of ultrasonic dispersion with a power of 50W to 360W; the time of ultrasonic dispersion is 10 to 30 minutes (e.g., 20 minutes). It is further preferred that the temperature of the vacuum oven is from room temperature to 80 ℃, the vacuum degree is from 0.01 to 0.09 MPa, and the dipping time is from 0.5 to 2 hours (e.g., 1 or 1.5 hours).

In other preferred embodiments, in step (2), the phase change material is incubated at 80 to 120 ℃ (e.g., 90, 100, or 110 ℃) for 5 to 20 minutes (e.g., 10 or 15 minutes) to place the phase change material in a substantially molten state. Preferably, in the step (2), the mass ratio of the self-repairing agent impregnated bead capsule to the phase change material is 1: (0.4 to 0.8), for example, 1: (0.4, 0.5, 0.6 or 0.7). If the amount of phase change material is too low, the self-healing agent impregnated microbead capsule may not be sufficiently coated; if the amount of the phase change material is too large, the thickness of the coated phase change material layer may be too large, so that the self-repairing agent therein cannot be smoothly released to perform the self-repairing function when the microcapsule is damaged.

In other preferred embodiments, in step (3), the spraying is achieved by pouring the dual function mixture into a spray gun preheated at 80 to 120 ℃ (e.g., 90, 100, or 110 ℃). Preferably, in step (3), the collection plate is a glass plate.

Reference is now made to fig. 1. Fig. 1 shows some more specific embodiments of the method according to the first aspect of the invention. As shown in fig. 1, the method comprises the steps of:

(1) Preparing porous glass beads by subcritical water treatment method

Placing the hollow glass beads into a 0-1 mol/L sodium hydroxide aqueous solution (the mass ratio of the glass beads to the sodium hydroxide aqueous solution is 1 (20-100) to obtain a hollow bead mixture, placing the hollow bead mixture into a high-temperature high-pressure reaction kettle with magnetic stirring, heating the reaction kettle to 150-300 ℃, increasing the pressure in the reaction kettle to 0.5-9 MPa along with the temperature increase, keeping the reaction kettle for 1-3 hours, naturally cooling the reaction kettle to room temperature, cleaning the product by deionized water, and soaking the product in a vacuum oven at the temperature of room temperature to 80 ℃ and under the vacuum degree of 0.01-0.09 MPa to obtain the hollow porous glass beads;

(2) Self-repairing agent @ glass microsphere microcapsule prepared by impregnation method

The dried hollow porous glass beads are placed into a self-repairing agent (mass ratio of 1 (2-10)), dispersed by ultrasonic for 10-30 min (ultrasonic power is 50W-360W), then placed into a vacuum oven to be soaked for 0.5-2 hours at room temperature to 80 ℃ and vacuum degree of 0.01-0.09 MPa, bubbles in the hollow glass beads are fully removed, the self-repairing agent is gradually soaked into the cavities of the glass beads through the porous surfaces, and then placed for 3-24 hours at normal temperature to improve the soaking rate of the self-repairing agent. Filtering and solvent cleaning the immersed product to remove the residual self-repairing agent on the outer surface of the glass bead, thereby obtaining a self-repairing agent@glass bead microcapsule;

(3) Preparation of self-repairing agent @ glass bead/self-lubricant double-wall microcapsule

Heating the solid paraffin to 80-120 ℃, and then preserving heat for 5-20 min to enable the solid paraffin to be fully melted. Adding the self-repairing agent @ glass microsphere microcapsule into molten paraffin (the mass ratio of the microcapsule to the paraffin is 1:0.4-0.8), uniformly stirring, pouring the mixture into a spray gun preheated at 80-120 ℃, spraying the mixture in the spray gun onto a glass plate, naturally cooling, and collecting a product to obtain the self-repairing agent @ glass microsphere/paraffin double-wall microcapsule (namely the double-functional microcapsule).

In some preferred embodiments, the resin matrix is selected from one or more of epoxy, polyurethane, alkyd resins.

The choice of curing agent is determined by the choice of resin matrix. In general, when the resin matrix is sold, the corresponding curing agent is added. Thus, in the present invention, the curing agent does not need to list the corresponding curing agent for each resin matrix, and it is fully within the ability of one skilled in the art to select the corresponding curing agent according to the choice of resin matrix.

In other preferred embodiments, the resin matrix mixture comprises a resin matrix, a curing agent, and a solvent in a mass ratio of 3:1:1.

In other preferred embodiments, the solvent is selected from one or more of ethanol, isopropanol.

In other preferred embodiments, the microcapsules are added in an amount of 1 to 20 mass%.

In other preferred embodiments, the cure is room temperature cure, with a cure time of 24 to 72 hours.

In some more specific embodiments, the method produces a self-repairing/self-lubricating dual-function composite in the form of a mold-forming material, the method comprising the steps of:

(2) Spraying the dual-function microcapsules according to the second aspect of the present invention into the resin matrix mixture through a spray gun while stirring the resin matrix mixture, wherein the microcapsules are added in an amount of 1-20wt.% (based on the total weight of the resin matrix and the curing agent) to obtain a resin mixture, and the resin matrix can be epoxy resin, polyurethane resin, alkyd resin and the like;

(3) And injecting the resin mixture into a forming die, and curing at room temperature for 24 to 72 hours to obtain the polymer-based self-repairing self-lubricating dual-function composite material.

In other more specific embodiments, the method produces a self-repairing, self-lubricating, bi-functional composite material in the form of a coating, and comprises the steps of:

(1) Polishing a coated substrate (usually a metal plate) by sand paper, cleaning by deionized water and ethanol, and drying in an oven for later use;

(2) Preparing a resin matrix mixture comprising a resin matrix, a curing agent, and a solvent;

(3) Spraying the double-function microcapsules according to the second aspect of the present invention to the resin matrix mixture (the addition amount of the double-function microcapsules is 1-20 wt% based on the total weight of the resin matrix and the curing agent) through a spray gun, and uniformly stirring (magnetic stirring can be carried out in a resin matrix mixture container during spraying), so as to obtain a resin mixture containing the microcapsules, wherein the resin matrix can be epoxy resin, polyurethane resin, alkyd resin or the like;

(4) Uniformly coating the resin mixture containing the microcapsules on the surface of a substrate (the thickness of a coating dry film can be regulated to be 50-500 mu m according to the requirement), and curing for 24-72 hours at room temperature to prepare the self-repairing self-lubricating double-function composite material coating.

In other more specific embodiments, the method produces a self-repairing, self-lubricating, bi-functional composite coating in the form of an alternating coating, and the method comprises the steps of:

(2) A resin matrix mixture is formulated that includes a resin matrix, a curing agent, and a solvent.

(3) Two spray guns were prepared, spray gun 1 was charged with the resin matrix mixture, and spray gun 2 was charged with the dual function microcapsules of the second aspect of the present invention (the temperature in the spray gun was maintained in the temperature range of 80-120 ℃). Placing the coated substrate on a heating table, controlling the temperature of the heating table within the temperature range of room temperature-50 ℃, spraying the resin mixture in the spray gun 1 on the surface of the substrate to form a layer of resin coating, placing for 5-30 min, after the solvent volatilizes, spraying the microcapsules in the spray gun 2 on the surface of the coating (the adding amount of the microcapsules is 1-20 wt%), repeating the above operation, spraying the resin layer and the microcapsules for a plurality of times as required, spraying the resin coating on the last layer, curing the coating at room temperature for 24-72h after spraying, and finally preparing the self-repairing self-lubricating double-functional composite coating.

In some embodiments, the difunctional mixture produced in step (2) of the method of the first aspect of the present invention may be substituted for the difunctional microcapsules.

In some preferred embodiments, the material is a mold cure molding material.

In other preferred embodiments, the material is a coating material, more preferably the thickness of the coating material is 50 to 500 microns (e.g., 100, 200, 300, or 400 microns).

Examples

Preparation example 1

1g of hollow glass beads (see figure 2, figure (a)) with an outer diameter of 20 μm and an inner diameter of 18 μm and 40 mL (0.1 mol/L) sodium hydroxide aqueous solution are added into a reaction kettle, the temperature is raised to 250 ℃ in a closed state, after maintaining 2h at the temperature, the reaction kettle is naturally cooled to room temperature, and the porous hollow glass beads are obtained after filtration, deionized water washing and drying.

Dispersing 1g porous hollow glass beads into 10 g linseed oil as a self-repairing agent, performing ultrasonic dispersion for 20 min with ultrasonic power of 180W, placing into a vacuum oven, immersing for 30 min at 50 ℃ and under a vacuum degree of 0.06 MPa, placing into 12 h in air, filtering, and washing out linseed oil on the outer surfaces of the glass beads with an ethyl acetate solvent to obtain a self-repairing agent @ glass bead microcapsule (see figure 2 (b)).

Melting 1.2 g solid paraffin (melting point 70 ℃) at 120 ℃ for 10 min, placing a spray gun into a baking oven at 120 ℃ for full preheating (preheating to 120 ℃), adding 2g of self-repairing agent @ glass microsphere microcapsules into the molten paraffin, stirring uniformly, pouring into the preheated spray gun, taking a smooth glass plate as a collecting plate, spraying the mixture in the spray gun onto the glass plate, converting the paraffin into a solid state at room temperature from a molten liquid state, wrapping the solid state on the outer surface of the self-repairing agent @ glass microsphere microcapsules, and collecting the product to obtain the self-repairing agent @ glass microsphere/paraffin microcapsule (see a graph (c) of fig. 2).

Preparation example 2

The procedure was carried out in substantially the same manner as in preparation example 1, except that isocyanate was used as a self-repairing agent instead of linseed oil.

Preparation example 3

The procedure was carried out in substantially the same manner as in preparation example 1, except that epoxy resin was used as a self-repairing agent instead of linseed oil.

Preparation example 4

The process was carried out in substantially the same manner as in preparation example 1 except that the porous hollow glass microspheres were used in an amount of 5g.

Preparation example 5

The process was carried out in substantially the same manner as in preparation example 1 except that the amount of paraffin wax used was 1.6g.

Preparation example 6

The process was carried out in substantially the same manner as in preparation example 1 except that the amount of paraffin wax used was 0.8g.

As a result, it was found that the structurally intact bifunctional microcapsules were produced in each of preparation examples 1 to 6.

Application example 1

The epoxy resin, the curing agent (the epoxy resin and the curing agent are purchased from the institute of petrochemistry of the university of Heilongjiang) and the ethanol solvent are uniformly mixed according to the mass ratio of 3:1:1 to prepare the resin matrix mixture. While stirring the resin matrix mixture, the microcapsules prepared in preparation example 1 were sprayed into the resin matrix mixture from a spray gun to uniformly disperse the microcapsules in the resin mixture, thereby obtaining an epoxy resin mixture, wherein the microcapsules account for 5. 5 wt% by mass of the resin matrix mixture. And pouring the epoxy resin mixture into a forming die, and curing 24 h at room temperature to prepare the self-repairing self-lubricating dual-functional composite material.

Application example 2

And (3) polishing the stainless steel plate by using sand paper, cleaning by using deionized water and ethanol, and drying in an oven for standby.

Uniformly mixing epoxy resin, a curing agent (epoxy resin and curing agent of the institute of petrochemistry of the academy of sciences of the black dragon river) and an ethanol solvent according to a mass ratio of 3:1:1 to obtain a resin matrix mixture. While stirring the resin matrix mixture, the microcapsules prepared in preparation example 1 were sprayed into the resin matrix mixture from a spray gun to uniformly disperse the microcapsules in the resin mixture, thereby obtaining an epoxy resin mixture, wherein the mass ratio of the microcapsules to the resin mixture is 10 wt%. And uniformly coating the epoxy resin mixture on the treated steel plate, curing the steel plate at room temperature by 48 h with a dry film thickness of about 300 mu m, and preparing the self-repairing self-lubricating double-function composite coating.

Application example 3

Uniformly mixing epoxy resin, a curing agent (epoxy resin and curing agent of the institute of petrochemistry of the university of Heilongjiang) and an ethanol solvent according to a mass ratio of 3:1:1 to prepare a resin matrix mixture.

The resin matrix mixture is then placed into a spray gun 1. The microcapsules prepared in preparation example 1 were placed in a spray gun 2 (the temperature in the spray gun was maintained in the temperature range of 80-120 ℃). The stainless steel plate was placed on a heating table, and the temperature of the heating table was raised to 40 ℃. Spraying the resin matrix mixture in the spray gun 1 on the surface of a stainless steel plate to form a layer of resin coating, standing for 10 min, and spraying the microcapsules in the spray gun 2 on the surface of the coating (the adding amount of the microcapsules is 10 wt percent based on the total weight of the resin matrix and the curing agent, and the whole text relates to the adding amount expenditure of the microcapsules, which are based on the total weight of the resin matrix and the curing agent) to form a microcapsule layer. And spraying a resin coating, a microcapsule layer and a resin coating in sequence according to the method. And (3) curing the coating at room temperature after spraying to 72h to prepare the self-repairing self-lubricating double-functional composite material coating.

Test example 1: self-lubricating properties of epoxy coatings

And adopting a friction and wear experiment, and evaluating the self-lubricating performance of the epoxy resin composite coating through the change of the friction coefficient and the wear amount. The linseed oil@glass bead/paraffin microcapsule prepared in preparation example 1 is added into an epoxy resin coating (the preparation method is the same as that of application example 2), the addition amounts are 0, 5, 10 and 15 wt percent respectively, the friction coefficient and the abrasion loss of the composite material coating gradually decrease along with the increase of the addition amount of the microcapsule, the friction coefficient of the epoxy resin composite material coating added with 10 wt percent of linseed oil@glass bead/paraffin microcapsule decreases from 0.5156 to 0.0662, and the friction loss decreases from 0.2854 g/0.5h to 0.098g/0.5h. However, when the content of the microcapsules is increased to 15 wt%, the friction coefficient and the abrasion loss of the composite coating are increased, and the reason is that the mechanical property of the resin matrix is affected by the excessive addition of the microcapsules, and the mechanical property is also a main reason for affecting the friction and abrasion performance of the material. The experimental results show that when the linseed oil@glass beads/paraffin microcapsules with the particle size of about 20 microns are added, the epoxy resin composite coating has the best antifriction and wear-resistant effect, namely self-lubricating performance.

Test example 2: self-healing properties of epoxy coatings

The self-healing properties of the epoxy composite coatings were evaluated by immersing the coatings in a 3.5. 3.5 wt.% aqueous NaCl salt solution for 15 days using a salt spray test, and observing the corrosion at the scratch of the coatings (see table 1 below). The linseed oil @ glass beads/paraffin microcapsules were added to the epoxy resin coating in amounts of 0, 5, 10,15 and wt% respectively, the coating was prepared according to the method of application example 2, and then cross scratches were scratched on the surface of the coating, with the scratch depth reaching the metal substrate. The coating was then left at room temperature 72 f h f, allowing the scratch to self-repair. In the process, the microcapsule at the scratch is broken, and the released linseed oil generates a crosslinking reaction to form a self-repairing film after encountering oxygen in the air, so that the scratch is repaired. Corrosion of the coating after soaking for days 1, 5, 10 and 15 was observed and recorded. The figures (a 1-a 4) show the corrosion of pure epoxy coating, and it can be seen that the scratch of the coating without the microcapsule starts to corrode after soaking on the 1 st day, and the scratch has obvious rust, and the longer the soaking time, the more serious the corrosion phenomenon. Figures (b 1-b 4) are epoxy coatings with 5 wt% microcapsules added, which is slightly better than pure epoxy coatings, but the scratch corrosion is still more severe after 15 days of soaking, indicating that 5 wt% microcapsules release insufficient linseed oil repair agent to repair the scratch. Figures (c 1-c 4) are epoxy coating corrosion cases with 10 wt% microcapsules added, and it can be observed that the coating has almost no corrosion during the entire soaking period, indicating that the new self-healing film formed at the scratch prevents penetration of the corrosive medium, thereby inhibiting corrosion of the metal substrate. Figures (d 1-d 4) are epoxy coating corrosion conditions with 15 wt% microcapsules added, and it can be observed that the coating is corrosion-resistant on day 10 of immersion, which is better than pure epoxy coating, but not as good as epoxy coating with 10 wt% microcapsules added, mainly because the excessive microcapsules content affects the mechanical properties of the resin matrix and the interfacial adhesion with the substrate, and thus the overall corrosion resistance of the coating. The experimental results show that when the linseed oil@glass beads/paraffin microcapsules with the particle size of about 20 microns are added, the epoxy resin composite material coating has the best anti-corrosion effect, namely the self-repairing performance.

TABLE 1 test design protocol for test example 2

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of preparing a self-repairing self-lubricating bi-functional microcapsule, the method comprising the steps of:

(3) And spraying the bifunctional mixture on a collecting plate, and collecting the cooled bifunctional mixture from the collecting plate to obtain the bifunctional microcapsule containing the self-lubricant serving as a wall material and the self-repairing agent serving as a core material.

2. The method according to claim 1, characterized in that:

the self-repairing agent is one or more self-repairing agents selected from drying oil, isocyanate and epoxy resin; and/or

The self-lubricant is a phase change material.

3. The method according to claim 2, characterized in that:

the phase change material is paraffin wax in a solid state at room temperature.

4. A method according to claim 3, characterized in that:

the melting point of the paraffin wax is 45 to 70 ℃.

5. The method according to claim 1, characterized in that:

the hollow porous microbeads are spherical microbeads with the outer diameter of 5-200 micrometers and the inner diameter of 2-180 micrometers.

6. The method according to claim 5, wherein:

the hollow porous micro beads are hollow porous glass micro beads.

7. The method according to claim 5, wherein:

the hollow porous microbeads are prepared by the following method: and (3) placing the hollow glass beads into alkali liquor to obtain a hollow glass bead mixture, placing the hollow glass bead mixture into a reaction kettle, heating to 150-300 ℃ and heating the pressure in the reaction kettle to 0.5-9 MPa, preserving heat and pressure for 1-3 hours, and then cooling to room temperature to obtain the hollow porous glass beads.

8. The method according to claim 7, wherein:

the alkali liquor is sodium hydroxide aqueous solution or potassium hydroxide aqueous solution with concentration of 0 to 1M.

9. The method according to claim 1, characterized in that:

step (1) is performed by the following means: adding the hollow porous microbeads into a self-repairing agent, dispersing uniformly, putting into a vacuum oven to remove bubbles in the hollow porous microbeads, enabling the self-repairing agent to be immersed into the hollow porous microbeads, standing for 3-24 hours at normal temperature, filtering and cleaning the obtained product, and obtaining the self-repairing agent-immersed microbead capsules.

10. The method according to claim 9, wherein:

the mass ratio of the hollow porous microbeads to the self-repairing agent is 1 (2-10).

11. The method according to claim 9, wherein:

the dispersion is carried out in an ultrasonic dispersion mode, and the power of ultrasonic dispersion is 50W to 360W; the time of ultrasonic dispersion is 10 to 30 minutes.

12. The method according to claim 9, wherein:

the temperature of the vacuum oven is between room temperature and 80 ℃, the vacuum degree is between 0.01 and 0.09 MPa, and the dipping time is between 0.5 and 2 hours.

13. The method according to claim 1, characterized in that:

in step (2), the self-lubricant is a phase change material which is incubated at 80 to 120 ℃ for 5 to 20 minutes to bring the phase change material into a substantially molten state.

14. The method according to claim 13, wherein:

in the step (2), the mass ratio of the self-repairing agent impregnated microsphere capsule to the phase change material is 1: (0.4 to 0.8).

15. The method according to claim 1, characterized in that:

in step (3), the spraying is achieved by pouring the dual function mixture into a spray gun preheated at 80 to 120 ℃ for spraying.

16. The method according to claim 15, wherein:

in step (3), the collection plate is a glass plate.

17. A bi-functional microcapsule obtainable by the process according to any one of claims 1 to 16.

18. A method of preparing a self-repairing, self-lubricating, bi-functional composite material, the method comprising:

(2) Spraying the dual-function microcapsules of claim 17 into the resin matrix mixture and uniformly dispersing while stirring the resin matrix mixture to prepare a resin mixture;

19. The method according to claim 18, wherein:

the resin matrix is selected from one or more of epoxy resin, polyurethane resin and alkyd resin;

the resin matrix mixture comprises a resin matrix, a curing agent and a solvent in a mass ratio of 3:1:1;

the solvent is selected from one or more of ethanol and isopropanol;

the microcapsule is added in an amount of 1 to 20 mass%; and/or

Curing to room temperature curing for 24 to 72 hours.

20. The self-repairing, self-lubricating, bi-functional composite material made by the method of claim 19.

21. The self-repairing, self-lubricating, bi-functional composite of claim 20, wherein:

the material is a mold curing molding material.

22. The self-repairing, self-lubricating, bi-functional composite of claim 20, wherein:

the material is a coating material.

23. The self-repairing, self-lubricating, bi-functional composite of claim 22, wherein:

the thickness of the coating material is 50 to 500 micrometers.