An egg-shaped shell film linkage material crack self-repairing healing agent, a production device and application thereof

Abstract

The application belongs to the technical field of crack repair of coal mine air leakage blocking materials, and relates to an egg-shaped shell membrane linkage material crack self-repairing healing agent, a production device and application thereof. The crack self-repairing healing agent comprises a spherical inner core, an egg-shaped membrane, a membrane shell interlayer and an egg-shaped shell from inside to outside in sequence. The spherical inner core is a biological catalyst. The membrane shell interlayer contains a healing reaction agent and a brittle dendritic linker. The preparation method comprises the following steps: coating the biological catalyst through the egg-shaped membrane, connecting the egg-shaped membrane with the egg-shaped shell through the brittle dendritic linker, filling the healing reaction agent between the egg-shaped membrane and the egg-shaped shell, and finally forming the egg-shaped shell membrane linkage material crack self-repairing healing agent. The egg-shaped shell membrane linkage material crack self-repairing healing agent can not only realize self-healing of concrete without external water source, but also can increase the bending and compressive strength of cement-based materials, and is conducive to realizing resource utilization of solid waste.

Description

Technical Field

[0001] This invention belongs to the technical field of crack repair in coal mine sealing materials, and relates to an oval shell membrane linkage material crack self-healing agent, production device and its application. Background Technology

[0002] Concrete is one of the most widely used building materials. However, due to factors such as external loads, alkali-aggregate reaction, and drying shrinkage, internal or surface microcracks inevitably form during preparation and use. If these microcracks are not repaired in time, external moisture and other corrosive substances can enter the concrete through these cracks, accelerating the corrosion of reinforcing steel and the deterioration of the concrete, thus shortening its service life. Currently, the concept of self-healing in cement-based materials has received extensive research from scholars. Self-healing is generally divided into autonomous healing and self-healing. Self-healing relies on the further hydration of unreacted binders and the carbonation of calcium hydroxide; this mechanism is not effective in repairing typical cracks in concrete and its performance is difficult to optimize. In autonomous healing, healing materials are immersed in media such as hydrogels, microcapsules, porous aggregates, or biochar and mixed with concrete. When the media breaks down, the healing material is released into the crack area, reacting with the cementitious matrix or other materials to heal and seal the crack surface. Among the self-healing methods currently under research, microbial and enzyme-based strategies for self-repairing concrete cracks are an emerging field. Microbial-induced carbonate precipitation (MICP) relies on the biomineralization capabilities of bacteria to produce self-healing agents under suitable environmental conditions. Enzyme-induced carbonate precipitation (EICP) relies on plant-derived urease to precipitate carbonates. Although MIP technology has been widely used in sand consolidation, this method has some limitations. For example, the growth of certain bacteria in cement-based materials requires specific temperature, oxygen, and pH values. Furthermore, compared to the size of microorganisms (typically between 12 nm and 300 nm), ureases are relatively small (approximately 500 nm), which makes EICP applicable to finer pore spaces. However, when EICP activates cracks in concrete, sufficient water is often required to promptly fill the microcracks and restore the concrete's durability and mechanical properties. Summary of the Invention

[0003] This invention addresses the aforementioned problems by providing a self-healing agent for cracks in oval-shaped shell-membrane interconnected materials, its production apparatus, and its applications. The oval-shaped shell-membrane interconnected material self-healing agent prepared by this invention will rupture under external pressure, and the oval membrane will break down under the action of brittle dendritic connectives, releasing a biocatalyst. The biocatalyst can decompose the CO(NH2)2 reagent in the healing reactant to generate carbonate ions, which ultimately combine with calcium ions in the system to form calcium carbonate precipitate. Simultaneously, this oval-shaped shell-membrane interconnected material self-healing agent can reduce the need for external water sources, spontaneously generating calcium carbonate precipitate without the addition of external water. Therefore, it provides a green and environmentally friendly oval-shaped shell-membrane interconnected material self-healing agent for the field of concrete self-healing, which reduces mineralization time.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] This invention provides a self-healing agent for cracks in an oval-shaped shell-membrane linkage material, comprising, from the inside out, a spherical core, an oval membrane, a membrane-shell interlayer, and an oval shell; the spherical core is a biocatalyst; the membrane-shell interlayer contains a healing reactant and a brittle dendritic connector;

[0006] The biocatalyst components include one or more of soybean urease, canavon bean urease, watermelon seed urease, potato urease, and jujube tree branch urease.

[0007] The healing reaction agent includes water, CO(NH2)2 reagent and soluble calcium salt;

[0008] The brittle dendritic connector is obtained by coating a dendritic connector with water glass; the dendritic connector is a loofah or a plastic blind drain.

[0009] The oval membrane comprises fly ash and sodium carbonate; the oval shell comprises acrylic resin, bisphenol A epoxy resin and an initiator.

[0010] Preferably, the diameter of the spherical core is 2.4 to 2.8 mm.

[0011] Preferably, the thickness of the oval membrane is 0.1 to 0.2 mm.

[0012] Preferably, the fly ash is selected from solid waste from coal-fired power plants, coal gangue or coal slime integrated utilization power plants; the mass ratio of SiO2, Al2O3, Fe2O3 and CaO in the fly ash is (13-15):(1-4):(4-7):(2-5).

[0013] Preferably, the mass ratio of the dendritic connector to the water glass is (3-5):(5-10).

[0014] Preferably, the particle size of the dendritic connector is 1 to 2.5 mm.

[0015] Preferably, the ratio of the total mass of the biocatalyst and the egg-shaped membrane to the mass of the brittle dendritic connector is 2:1.

[0016] Preferably, the mass ratio of the healing agent to the brittle dendritic connective is (1-2):(3-4).

[0017] Preferably, the mass ratio of water, CO(NH2)2 reagent and soluble calcium salt in the healing reaction agent is (8-10):(2-3):(1-2).

[0018] Preferably, the soluble calcium salt is selected from one or more of calcium chloride, calcium lactate, and calcium acetate.

[0019] Preferably, the ratio of the mass of the oval shell to the total mass of the spherical inner core, the oval membrane, and the membrane-shell interlayer is (2-5):(17-20).

[0020] Preferably, the mass ratio of the bisphenol A epoxy resin, acrylic resin and initiator is (26-27):(5-6):1.

[0021] Preferably, the initiator is selected from one or more of nano-titanium dioxide, cadmium sulfide, or bismuth vanadate.

[0022] The present invention also provides a method for preparing the self-healing agent for cracks in the oval shell-membrane linkage material, the steps of which are as follows:

[0023] S1. Form the biocatalyst into spherical particles;

[0024] S2. After acid leaching of fly ash, filter to obtain solid slag. Stir the solid slag, sodium carbonate and water at 80-110℃ to react. After the reaction is completed, filter and the filtrate is the oval membrane solution.

[0025] S3. Dissolve acrylic resin in bisphenol A type epoxy resin, and then add initiator at 100-120℃ under light-protected conditions and stir to obtain an oval shell mixture;

[0026] S4. Immerse the dendritic linker in water glass, let it stand, then take it out and drain it, and let it stand again to obtain a brittle dendritic linker.

[0027] S5. The oval membrane solution described in step S2 is used to encapsulate the biocatalyst particles described in step S1 to obtain oval membrane / biocatalyst particles; the oval membrane / biocatalyst particles are uniformly mixed with the brittle dendritic connector from step S4, and after standing and draining, brittle dendritic connector / oval membrane / biocatalyst particles are obtained; the brittle dendritic connector / oval membrane / biocatalyst particles and the healing agent are coated with an oval shell-shaped mixture using a pelletizing device, and then immediately subjected to light irradiation to obtain solidified oval shell membrane linkage material crack self-healing agent particles, and then the oval shell membrane linkage material crack self-healing agent is protected in sodium alginate protective solution.

[0028] During the falling process of brittle dendritic connectors / ovoid membranes / biocatalyst particles, healing agents, and eggshell-shaped mixtures, light irradiation is applied. Through photosensitivity, the eggshell-shaped mixture gradually solidifies and forms, encapsulating the healing agents and brittle dendritic connectors / ovoid membranes / biocatalyst particles, thus forming an eggshell-membrane linkage material crack self-healing agent.

[0029] Preferably, step S1 is as follows: take 100 parts of biocatalyst and add 10 to 20 parts of water, and use a multi-functional granulator to make the biocatalyst into spherical particles at a rate of 5g / batch.

[0030] Preferably, the acid leaching method in step S2 is as follows: 100-120 parts of fly ash are added to 220-260 parts of 1mol / L hydrochloric acid and leached for 30 minutes.

[0031] Preferably, the mass ratio of solid residue, sodium carbonate and water in step S2 is 10:(2-3):(20-30).

[0032] Preferably, the reaction time in step S2 is 1 to 1.5 hours.

[0033] Preferably, step S3 is as follows: acrylic resin is added to bisphenol A type epoxy resin, heated in a water bath at 100-120°C under magnetic stirring until the solid is completely dissolved, then an initiator is added and the water bath heating and stirring continues for 20-30 minutes. After the sample cools, it is allowed to stand in the dark to obtain an oval shell mixture. The oval shell mixture can be cured through a photosensitive reaction under the action of the initiator.

[0034] Preferably, the settling time in step S4 is 5 minutes, and the settling time again is 1 to 2 hours.

[0035] The dropping principle of the brittle dendritic linker / ovoid membrane / biocatalyst particles, healing agent and eggshell-shaped mixture described in step S5 is that the eggshell-shaped mixture is quantitatively titrated to the dropping device by a metering pump, and the brittle dendritic linker / ovoid membrane / biocatalyst particles and healing agent enter the eggshell-shaped mixture through a metering needle.

[0036] This invention also provides a production apparatus for the above-mentioned self-healing agent for cracks in oval shell membrane linkage materials. Following the production process flow, it sequentially includes a multi-functional granulator, a connecting pipe, an oval membrane solution storage tank, a first vibrating filter screen, a first conveyor belt, a pelletizing unit, a second vibrating filter screen, a second conveyor belt, and a storage tank. The discharge port of the multi-functional granulator is connected to the inlet of the connecting pipe, and the outlet of the connecting pipe is vertically positioned above the opening of the oval membrane solution storage tank. The first vibrating filter screen is positioned below the outlet of the oval membrane solution storage tank. One end of the first conveyor belt is positioned below the first vibrating filter screen, and the other end is positioned above the inlet of the pelletizing unit. The pelletizing unit includes a healing reaction agent storage tank and an oval shell mixture storage tank. The system includes a tank, a T-tube, a pellet-dropping device, and a sodium alginate protective solution storage tank. One end of the conveyor belt is positioned above the inlet of the healing agent storage tank. The outlet of the healing agent storage tank and the outlet of the oval shell mixture storage tank are connected to the two inlets of the T-tube, respectively. The outlet of the T-tube is connected to the inlet of the pellet-dropping device. A metering pump is installed in the T-tube pipeline between the healing agent storage tank, the oval shell mixture storage tank, and the pellet-dropping device. The outlet of the pellet-dropping device is vertically positioned above the inlet of the sodium alginate protective solution storage tank. A second vibrating filter is positioned below the outlet of the sodium alginate protective solution storage tank. One end of the conveyor belt is positioned below the second vibrating filter, and the other end is positioned above the inlet of the storage tank.

[0037] In this invention, the process of preparing the self-healing agent for cracks in oval shell-membrane linkage materials using the above-mentioned production apparatus is as follows:

[0038] (1) Take 100 parts of biocatalyst and add 10-20 parts of water. Use a multi-functional granulator to make the biocatalyst into spherical particles at a speed of 5g / time. Transfer the spherical particles of biocatalyst to an oval membrane solution storage tank through a connecting pipe. The spherical particles of biocatalyst are wrapped by the oval membrane solution in the oval membrane solution storage tank to form oval membrane / biocatalyst particles. Then, when the contents of the oval membrane solution storage tank reach a certain weight, the bottom of the oval membrane solution storage tank will automatically open to release the oval membrane / biocatalyst particles and part of the oval membrane solution at the bottom and fall into the filter vibrating screen to separate the oval membrane / biocatalyst particles and the oval membrane solution. The oval membrane / biocatalyst particles and the brittle dendritic connectors on the surface of the filter vibrating screen are mixed by vibration. After standing and draining for 1-2 hours, brittle dendritic connectors / oval membrane / biocatalyst particles are obtained.

[0039] (2) The brittle dendritic linker / ovoid membrane / biocatalyst particles are conveyed to the healing agent storage tank via a conveyor belt. The brittle dendritic linker / ovoid membrane / biocatalyst particles and the mixture of the healing agent and the ovoid shell in the ovoid shell mixture storage tank are then dripped into the sodium alginate protective solution at room temperature in the sodium alginate protective solution storage tank by a metering pump. During its descent, it is irradiated with light, and through photosensitive action, the ovoid shell mixture gradually solidifies and forms, encapsulating the healing agent and the brittle dendritic linker / ovoid membrane / biocatalyst particles, forming an ovoid shell membrane linkage material crack self-healing agent.

[0040] (3) The self-healing agent for cracks in the oval shell-membrane linkage material is separated from the sodium alginate protective solution in the storage tank using a second vibrating filter screen, and then washed with a 90% anhydrous ethanol solution and drained. The self-healing agent for cracks in the oval shell-membrane linkage material is then conveyed to the storage tank via a second conveyor belt for storage.

[0041] This invention relates to an oval-shaped shell-membrane linkage material crack self-healing agent, which mainly utilizes the principle that a biocatalyst can decompose CO(NH2)2 to generate carbonate ions, which combine with calcium ions in the system to form calcium carbonate precipitate. This enables automatic detection and healing of concrete cracks. The formed calcium carbonate precipitate is compatible with the main material, making it green, environmentally friendly, and pollution-free. Furthermore, the oval-shaped shell-membrane linkage material crack self-healing agent can achieve self-sufficiency in water supply without an external water source.

[0042] The oval shell can encapsulate brittle dendritic connectors / oval membranes / biocatalyst particles and healing agents, achieving good compatibility with cement-based materials. Furthermore, the oval shell has good water retention, preventing the internal healing agents from losing water during hydration.

[0043] By using one or more of nano-titanium dioxide, cadmium sulfide, and bismuth vanadate as initiators for the oval shell, highly catalytically active free radicals can be generated under the action of sunlight and ultraviolet light, resulting in strong photo-oxidation and reduction capabilities, thereby solidifying the oval shell.

[0044] The biocatalyst is encapsulated by an oval membrane, allowing it to separate from the healing agent. Under conditions of crack formation, the oval membrane breaks down along with the outer oval shell, releasing the biocatalyst, which then comes into contact with the healing agent, producing calcium carbonate precipitate.

[0045] Finally, the oval membrane is prepared using solid waste selected from coal-fired power plants, coal gangue, and coal slime integrated utilization power plants, enabling the reuse of solid waste. Furthermore, the oval membrane can be cured by drying and is not easily decomposed in aqueous solution. In other words, the oval shell membrane linkage material crack self-healing agent provided by this invention can effectively provide a basic guarantee for enzyme-induced calcium carbonate precipitation, solve the problem of concrete cracks, and achieve self-healing of concrete cracks without external water source, while also achieving green, environmentally friendly, and pollution-free characteristics.

[0046] This invention also provides the application of the self-healing agent for cracks in the oval shell-membrane linkage material, used to prepare self-healing cement, the steps of which are as follows:

[0047] a. After wetting the self-healing agent for cracks in the oval shell membrane linkage material with water, mix it into cement powder for coating, then sieve, let stand, and dry to obtain the self-healing agent for cracks in the cement / oval shell membrane linkage material.

[0048] b. Add the self-healing agent for cracks in the cement / oval shell membrane linkage material to the cement-based material to prepare self-healing cement.

[0049] After the self-healing cement has cured, if cracks occur under external pressure, the internal oval shell membrane linkage material and self-healing agent will successively rupture. Under the action of the brittle dendritic connector, the oval membrane breaks down, and the healing agent can quickly combine with the biocatalyst to generate carbonate precipitates, thereby achieving the healing of cement cracks.

[0050] Preferably, the mass ratio of the cement powder to the self-healing agent for cracks in the oval shell membrane linkage material in step a is (10-12):(2.5-5).

[0051] Preferably, the particle size of the self-healing agent for cracks in the cement / egg-shaped shell membrane linkage material is 4-5 mm.

[0052] Compared with existing technologies, the self-healing crack repair agent structure of this invention achieves linkage between the shell and membrane. Under external pressure, the rupture of the oval shell will affect the brittle dendritic connective tissue, ultimately leading to the simultaneous rupture of the oval membrane and the release of the biocatalyst within it. Upon contact with the healing reactant encapsulated in the oval shell, the biocatalyst decomposes and generates carbonate precipitates, achieving self-healing of concrete cracks.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] (1) The self-healing agent for cracks of the egg-shaped shell membrane linkage material of the present invention achieves the separation of healing reactant and biocatalyst in structure compared with ordinary self-healing concrete capsules, and achieves self-healing of concrete cracks without the addition of water source.

[0055] (2) The biocatalyst decomposes the CO(NH2)2 reagent in the healing reaction agent to produce calcium carbonate ions. The calcium carbonate ions produced will combine with the calcium ions in the healing reaction agent to form calcium carbonate during use. It is green, environmentally friendly and pollution-free.

[0056] (3) The initiator added to the self-healing agent for cracks in the egg-shaped shell membrane linkage material of the present invention can improve the activity of the biocatalyst, increase the yield of calcium carbonate precipitation, and improve the strength of crack self-healing.

[0057] (4) The oval shell of the self-healing agent for cracks in the oval shell membrane linkage material of the present invention is an inorganic material, which can achieve good compatibility with cement-based materials, and the SiO2 and Al2O3 contained therein can participate in the hydration of cement and enhance the strength of cement-based materials.

[0058] (5) The oval shell membrane linkage material of the present invention has a self-healing agent for cracks. The oval shell can break under external pressure. Under the action of the brittle dendritic connector, the oval membrane will break, and the healing agent can quickly combine with the biocatalyst to shorten the mineralization time;

[0059] (6) The oval membrane of the self-healing agent for cracks in the oval shell membrane linkage material of the present invention is prepared from solid waste fly ash, which is conducive to realizing the resource utilization of solid waste;

[0060] (7) The self-healing crack repair agent of the present invention can improve the compressive and flexural strength of cement samples and achieve a self-healing effect of concrete cracks up to 80%. Attached Figure Description

[0061] Figure 1 Electron micrograph of a self-healing agent for cracks in an oval shell-membrane linkage material;

[0062] Figure 2 The mineralization rate of calcium carbonate precipitate generated by the self-healing agent for cracks in oval shell-membrane linkage materials prepared under different molar concentration gradients;

[0063] Figure 3 Scanning electron microscope images of the healing material generated by the self-healing agent of the egg-shaped shell-membrane linkage material cracked under different molar concentration gradients;

[0064] Figure 4 Images showing the degree of self-healing of material cracks in Embodiment 4 of the present invention;

[0065] Figure 5The material production apparatus described in Embodiment 1 of the present invention comprises: 1. a multi-functional granulator; 2. a connecting pipe; 3. an oval membrane solution storage tank; 4. a first filter vibrating screen; 5. a first conveyor belt; 60. a pellet dropping unit; 6. a healing reaction agent storage tank; 7. an oval shell mixture storage tank; 8. a T-tube; 81. a metering pump; 9. a pellet dropping device; 10. a sodium alginate protective solution storage tank; 11. a second filter vibrating screen; 12. a second conveyor belt; and 13. a storage tank. Detailed Implementation

[0066] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer with the description. However, the embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0067] Example 1

[0068] This embodiment provides a self-healing agent for cracks in an oval shell-membrane linkage material and a production device.

[0069] A production apparatus for a self-healing agent for cracks in an oval shell membrane linkage material, comprising, in sequence according to the production process flow, a multi-functional granulator 1, a connecting pipe 2, an oval membrane solution storage tank 3, a first vibrating filter 4, a first conveyor belt 5, a droplet unit 60, a second vibrating filter 11, a second conveyor belt 12, and a storage tank 13; the discharge port of the multi-functional granulator 1 is connected to the inlet of the connecting pipe 2, and the outlet of the connecting pipe 2 is vertically positioned above the opening of the oval membrane solution storage tank 3; the first vibrating filter 4 is positioned below the outlet of the oval membrane solution storage tank 3, and one end of the first conveyor belt 5 is positioned below the first vibrating filter 4, and the other end is positioned above the inlet of the droplet unit 60; the droplet unit 60 includes a healing reaction agent storage tank 6, an oval shell mixture storage tank 7, and a T-type... The system includes a tube 8, a pellet-dripping device 9, and a sodium alginate protective solution storage tank 10. The other end of the conveyor belt 5 is positioned above the inlet of the healing reaction agent storage tank 6. The outlet of the healing reaction agent storage tank 6 and the outlet of the oval shell mixture storage tank 7 are respectively connected to the two inlets of the T-tube 8. The outlet of the T-tube 8 is connected to the inlet of the pellet-dripping device 9. A metering pump 81 is installed in each of the T-tube 8 lines between the healing reaction agent storage tank 6, the oval shell mixture storage tank 7, and the pellet-dripping device 9. The outlet of the pellet-dripping device 9 is vertically positioned above the inlet of the sodium alginate protective solution storage tank 10. A second filtering vibrating screen 11 is positioned below the outlet of the sodium alginate protective solution storage tank 10. One end of the conveyor belt 12 is positioned below the second filtering vibrating screen 11, and the other end is positioned above the inlet of the storage tank 13.

[0070] The preparation of a self-healing agent for cracks in an oval shell-membrane linkage material using the above-mentioned apparatus follows these steps:

[0071] (1) Weigh 100 parts of biocatalyst and add 10-20 parts of water, stirring until a lumpy mixture is formed. Use a multi-functional granulator 1 to form the biocatalyst into spheres at a rate of 5g / batch, and then dry them in an oven at 25℃ to obtain biocatalyst particles.

[0072] The healing reaction agent in this embodiment consists of water, CO(NH2)2 reagent, and soluble calcium salt in a mass ratio of 8:2:1.

[0073] (2) 100 parts of solid waste (fly ash, in which the mass ratio of SiO2, Al2O3, Fe2O3 and CaO in the fly ash is 13:2:4:3) from a coal-fired power plant were added to 220 parts of 1 mol / L hydrochloric acid and leached for 30 min. After separation of liquid and slag, solid slag was obtained. Solid slag, sodium carbonate and water in a mass ratio of 10:2:25 were magnetically stirred for 1.5 h at a temperature of 80 °C. After filtration to remove slag, an oval membrane solution was obtained.

[0074] (3) Add acrylic resin to bisphenol A type epoxy resin, heat in a water bath at 100°C and stir with magnetic force until the solid is completely dissolved. Then add nano titanium dioxide and continue to heat and stir in a water bath for 20 minutes. After the sample cools down, let it stand in the dark for 12 hours to obtain an oval shell mixture.

[0075] (4) Take 5 portions of loofah sponge with a particle size of 2 mm, wash them with distilled water, and divide them evenly; then place the above dendritic connectors in 5 portions of water glass, let them stand for 5 minutes, take them out and drain them, let them stand for 1 hour to obtain brittle dendritic connectors.

[0076] The mass ratio of the bisphenol A epoxy resin, acrylic resin and initiator is 26:5:1;

[0077] (5) The biocatalyst particles from step (1) are transferred to the oval membrane solution storage tank 3 through the connecting pipe 2 for uniform coating; the coated oval membrane / biocatalyst particles fall into the filter vibrating screen 4, the oval membrane / biocatalyst particles are uniformly mixed with the brittle dendritic connector in the filter vibrating screen 4, and after standing and draining for 1 hour, brittle dendritic connector / oval membrane / biocatalyst particles are obtained.

[0078] The brittle dendritic linker / ovoid membrane / biocatalyst particles are transferred to the healing agent storage tank 6 via conveyor belt 5. The oval shell mixture from the oval shell mixture storage tank 7, the healing agent (100 parts CO(NH2)2 reagent and 100 parts calcium chloride solution) from the healing agent storage tank 6, and the brittle dendritic linker / ovoid membrane / biocatalyst particles are added dropwise via metering pump 81 through a dropper device 9 to the room-temperature sodium alginate protective solution (water, sodium lactate, and sodium alginate in a mass ratio of 1000:4) in the sodium alginate protective solution storage tank 10. In the mixture prepared by mixing 70, light irradiation was applied during its descent, causing the oval shell mixture to gradually solidify and form a self-healing agent for cracks in the oval shell membrane linkage material, encapsulating the healing reactant and brittle dendritic connectors / oval membrane / biocatalyst particles. The self-healing agent was then separated from the sodium alginate protective solution using a vibrating filter screen 11. The collected self-healing agent was washed with 90% anhydrous ethanol solution, air-dried, and transported to storage tank 13 via conveyor belt 12. The microstructure of the self-healing agent was observed using a scanning electron microscope, and the results are as follows: Figure 1 The average particle size of the self-healing agent for cracks in the oval shell-membrane linkage material shown is 4.5 mm.

[0079] The diameter of the spherical core is 2.8 mm.

[0080] The thickness of the oval membrane is 0.2 mm.

[0081] The mass ratio of the oval membrane / biocatalyst particles to the brittle dendritic connector is 2 to 1.

[0082] The mass ratio of the healing agent to the brittle dendritic connective is 2:3.

[0083] The ratio of the mass of the oval shell to the total mass of the spherical inner core, oval membrane, and membrane-shell interlayer is 4:19.

[0084] Example 2

[0085] This embodiment provides a method for preparing a self-healing agent for cracks in oval shell-membrane linkage materials.

[0086] The preparation steps of the self-healing agent for cracks in the oval shell-membrane linkage material are as follows:

[0087] The preparation method of the brittle dendritic linker / oval membrane / biocatalyst particles is the same as the steps in Example 1.

[0088] Acrylic resin was added to bisphenol A type epoxy resin, and the mixture was heated in a water bath at 100°C under magnetic stirring until the solid was completely dissolved. Then, nano titanium dioxide was added and the mixture was heated and stirred in a water bath for 20 minutes. After the sample cooled, it was allowed to stand in the dark for 12 hours to obtain an oval shell mixture.

[0089] The oval shell mixture, healing agent, and brittle dendritic linker / oval membrane / biocatalyst particles were added dropwise to a room-temperature sodium alginate protective solution via a metering pump 81 and a dropper device 9. During the drop, the mixture was exposed to light, causing it to gradually solidify and encapsulate the healing agent and the brittle dendritic linker / oval membrane / biocatalyst particles, forming a self-healing agent for cracks in the oval shell-membrane linkage material. The self-healing agent was then separated from the sodium alginate protective solution using a sieve. The collected self-healing agent was washed with a 90% anhydrous ethanol solution and air-dried.

[0090] The molar concentration gradients of CO(NH2)2 reagent and soluble calcium salt added to the healing agent were 0.0 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, and 2.0 mol / L, respectively. 20 g of the self-healing agent for the egg-shaped shell-membrane linkage material cracks prepared at the above different molar concentration gradients was placed in a beaker, completely broken up using a glass rod, and allowed to stand for 24 h.

[0091] test:

[0092] The beaker was dried in a constant temperature incubator at 100℃. The total mass of the beaker and the self-healing agent for the crack in the oval shell membrane linkage material was weighed and recorded as M1. The beaker was washed with 0.7mol / L hydrochloric acid to remove the calcium carbonate precipitate formed by the decomposition of CO(NH2)2 reagent and soluble calcium salt by the biocatalyst after the self-healing agent for the crack in the oval shell membrane linkage material was broken. The beaker was dried and weighed, and recorded as M2. The weight of calcium carbonate is M1-M2. The results are shown in Table 1.

[0093] Table 1. Amount of calcium carbonate precipitate generated by the self-healing agent for cracks in oval shell-membrane linkage materials prepared under different molar concentration gradients.

[0094]

[0095] The mineralization rate of calcium carbonate precipitate generated by the self-healing agent for cracks in oval shell-membrane linkage materials prepared under different molar concentration gradients is as follows: Figure 2 As shown in the image.

[0096] Electron micrographs of calcium carbonate precipitates formed by self-healing agents for cracks in oval shell-membrane linkage materials prepared under different molar concentration gradients are shown below. Figure 3 As shown in the image.

[0097] Table 1 shows that the amount of calcium carbonate precipitate generated by the self-healing agent for cracks in oval shell-membrane linkage materials prepared under different molar concentration gradients first increases and then remains constant. According to... Figure 2It can be seen that when the molar concentration is 1.0 mol / L, the amount of calcium carbonate precipitate generated is almost 100%, and when the molar concentrations are 1.5 mol / L and 2.0 mol / L, the amount of calcium carbonate precipitate generated is completely 100%. This is because the added biocatalyst has a limited ability to decompose CO(NH2)2, and mineralization is almost complete at a molar concentration of 1.0 mol / L. In conclusion, the highest calcium carbonate yield is achieved with a molar concentration of 1.0 mol / L in the self-healing agent for cracks in oval shell membrane linkage materials.

[0098] Example 3

[0099] A self-healing agent for cracks in an oval shell-membrane linkage material, its preparation method, and its application method.

[0100] The preparation steps of the self-healing agent for cracks in the oval shell-membrane linkage material are as follows:

[0101] The preparation method of the brittle dendritic linker / oval membrane / biocatalyst particles is the same as the steps in Example 1.

[0102] Acrylic resin was added to bisphenol A epoxy resin, and the mixture was heated in a water bath at 100°C with magnetic stirring until the solid was completely dissolved. Then, nano-titanium dioxide was added, and the mixture was heated and stirred in a water bath for another 20 minutes. After the sample cooled, it was allowed to stand in the dark for 12 hours to obtain an oval shell mixture. The oval shell mixture, the healing agent (CO(NH2)2 reagent and soluble calcium salt with a molar concentration of 1.0 mol / L), and the brittle dendritic linker / oval membrane / biocatalyst particles were added dropwise to a sodium alginate protective solution at room temperature via a metering pump 81 and a dropper device 9. During the drop, the mixture was irradiated with light, and the oval shell mixture gradually solidified and formed, encapsulating the healing agent and the brittle dendritic linker / oval membrane / biocatalyst particles to form a self-healing agent for cracks in the oval shell membrane linkage material. The self-healing agent for cracks in the oval shell membrane linkage material was separated from the sodium alginate protective solution using a sieve. The collected self-healing agent for cracks in the oval shell membrane linkage material was washed with 90% anhydrous ethanol solution and air-dried.

[0103] The method for using the self-healing agent for cracks in the oval shell-membrane linkage material is as follows:

[0104] A certain mass of the self-healing agent for cracks in the oval shell membrane linkage material was weighed, thoroughly moistened with water, and then placed in cement powder for encapsulation. The encapsulated self-healing agent for cracks in the oval shell membrane linkage material was separated from the cement using a steel sieve. The separated self-healing agent was then drained at room temperature (25℃) to obtain a cement / oval shell membrane linkage material self-healing agent. This cement / oval shell membrane linkage material self-healing agent was added to cement-based materials to prepare rectangular cement samples measuring 40×40×160cm. The dosages of the cement / oval shell membrane linkage material self-healing agent were 0%, 1%, 3%, 5%, and 7% of the cement mass, respectively, with a water-cement ratio of 0.60. After standard curing for 14 days, the samples were tested for compressive and flexural strength using a universal testing machine. The results are shown in Table 2.

[0105] Table 2. Crack self-healing agent dosage for different cement / oval shell membrane linkage materials; compressive and flexural strength of cement samples.

[0106]

[0107] Table 2 shows that the compressive strength of the cement / oval shell membrane crack self-healing agent improved when the dosage was 1% and 3%. However, when the dosage increased to 5%, the compressive strength gradually decreased. This is because the density of the cement sample decreased with the increase of gel capsule dosage, leading to a decrease in compressive strength. However, the flexural strength of the cement sample increased with the increase of dosage. This is because the oval shell is formed by the photosensitive reaction of acrylic resin and bisphenol A epoxy resin under the action of intermolecular hydrogen bonds, and it has strong flexural properties. Therefore, considering the combined effects of compressive and flexural strength, a dosage of 3% for the cement / oval shell membrane crack self-healing agent is recommended.

[0108] Example 4

[0109] A self-healing agent for cracks in an oval shell-membrane linkage material, its preparation method and application

[0110] The preparation steps of the self-healing agent for cracks in oval shell-membrane linkage materials are as follows:

[0111] The preparation method of the brittle dendritic linker / oval membrane / biocatalyst particles is the same as the steps in Example 1.

[0112] Acrylic resin was added to bisphenol A type epoxy resin, and the mixture was heated in a water bath at 100°C under magnetic stirring until the solid was completely dissolved. Then, nano titanium dioxide was added and the mixture was heated and stirred in a water bath for 20 minutes. After the sample cooled, it was allowed to stand in the dark for 12 hours to obtain an oval shell mixture.

[0113] The oval shell mixture, healing agent (CO(NH2)2 reagent and soluble calcium salt with a molar concentration gradient of 1.0 mol / L), and brittle dendritic linkers / oval membranes / biocatalyst particles were added dropwise into a room-temperature sodium alginate protective solution via a metering pump 81 and a dropper device 9. During the drop, the mixture was irradiated with light, causing the oval shell mixture to gradually solidify and form a self-healing agent for cracks in the oval shell membrane linkage material. The self-healing agent was then separated from the sodium alginate protective solution using a sieve. The collected self-healing agent was washed with 90% anhydrous ethanol solution and air-dried.

[0114] application:

[0115] A certain mass of the self-healing agent for cracks in the oval shell membrane linkage material was weighed, thoroughly moistened with water, and then placed in cement powder for encapsulation. The encapsulated self-healing agent for cracks in the oval shell membrane linkage material was separated from the cement using a steel sieve. The separated self-healing agent was then drained at room temperature (25℃) to obtain a cement / oval shell membrane linkage material self-healing agent. This cement / oval shell membrane linkage material self-healing agent was added to cement-based materials to prepare rectangular cement samples measuring 40×40×160cm. The dosage of the cement / oval shell membrane linkage material self-healing agent was 3% of the cement mass, the water-cement ratio was 0.60, and the samples were cured under standard conditions for 14 days. Three parallel samples were prepared. After artificially breaking the cement samples and allowing them to stand for 7 days, the degree of self-healing of the cracks was observed. The results are as follows: Figure 4 As shown.

Claims

1. A self-healing agent for cracks in an oval shell-membrane linkage material, characterized in that, From the inside out, it comprises a spherical core, an oval membrane, a membrane-shell interlayer, and an oval shell; the spherical core is a biocatalyst; the membrane-shell interlayer contains a healing agent and brittle dendritic connectives; The biocatalyst component is selected from one or more of soybean urease, canavon bean urease, watermelon seed urease, potato urease, and jujube tree branch urease. The healing reaction agent includes water, CO(NH2)2 reagent and soluble calcium salt; The brittle dendritic connector is obtained by coating a dendritic connector with water glass; The dendritic connector is a loofah sponge or a plastic blind drain; The oval membrane comprises: fly ash and sodium carbonate; the oval shell comprises: acrylic resin, bisphenol A epoxy resin and initiator. The preparation method of the self-healing agent for cracks in the oval shell-membrane linkage material includes the following steps: S1. Form the biocatalyst into spherical particles; S2. After acid leaching of fly ash, filter to obtain solid slag. Stir the solid slag, sodium carbonate and water at 80~110℃ to react. After the reaction is completed, filter and the filtrate is the oval membrane solution. S3. Dissolve acrylic resin in bisphenol A type epoxy resin, then add initiator and stir at 100~120℃ in the dark to obtain oval shell mixture; S4. Immerse the dendritic linker in water glass, let it stand, take it out and drain it, let it stand again to obtain a brittle dendritic linker. S5. The oval membrane solution described in step S2 is used to encapsulate the spherical particles described in step S1 to obtain oval membrane / biocatalyst particles; the oval membrane / biocatalyst particles are uniformly mixed with the brittle dendritic linker from step S4, and after standing and draining, brittle dendritic linker / oval membrane / biocatalyst particles are obtained; the brittle dendritic linker / oval membrane / biocatalyst particles and the healing reaction agent are coated with an oval shell-shaped mixture using a pelletizing device, and then immediately subjected to light irradiation to obtain solidified oval shell membrane linkage material crack self-healing agent particles; then the oval shell membrane linkage material crack self-healing agent is protected in sodium alginate protective solution; subsequently, the oval shell membrane linkage material crack self-healing agent is separated from the sodium alginate protective solution, and the collected oval shell membrane linkage material crack self-healing agent is washed with 90% anhydrous ethanol solution and air-dried; The initiator is selected from one or more of nano-titanium dioxide, cadmium sulfide, or bismuth vanadate.

2. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The diameter of the spherical core is 2.4~2.8 mm.

3. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The thickness of the oval membrane is 0.1~0.2 mm.

4. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The mass ratio of SiO2, Al2O3, Fe2O3 and CaO in the fly ash is (13~15):(1~4):(4~7):(2~5).

5. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The mass ratio of the dendritic connector to the water glass is (3~5):(5~10).

6. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The particle size of the dendritic connector is 1~2.5 mm.

7. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The ratio of the total mass of the biocatalyst and the oval membrane to the mass of the brittle dendritic connector is 2:

1.

8. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The mass ratio of the healing agent to the brittle dendritic connective is (1~2):(3~4).

9. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The mass ratio of water, CO(NH2)2 reagent and soluble calcium salt in the healing reaction agent is (8~10):(2~3):(1~2).

10. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The soluble calcium salt is selected from one or more of calcium chloride, calcium lactate, and calcium acetate.

11. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The ratio of the mass of the oval shell to the total mass of the spherical inner core, oval membrane, and membrane-shell interlayer is (2~5):(17~20).

12. The self-healing agent for cracks in oval shell-membrane linkage materials according to claim 1, characterized in that, The mass ratio of the bisphenol A type epoxy resin, acrylic resin and initiator is (26~27):(5~6):

1.

13. The method for preparing the self-healing agent for cracks in oval shell-membrane linkage materials according to any one of claims 1 to 12, characterized in that, The steps are as follows: S1. Form the biocatalyst into spherical particles; S2. After acid leaching of fly ash, filter to obtain solid slag. Stir the solid slag, sodium carbonate and water at 80~110℃ to react. After the reaction is completed, filter and the filtrate is the oval membrane solution. S3. Dissolve acrylic resin in bisphenol A type epoxy resin, then add initiator and stir at 100~120℃ in the dark to obtain oval shell mixture; S4. Immerse the dendritic linker in water glass, let it stand, take it out and drain it, let it stand again to obtain a brittle dendritic linker. S5. The oval membrane solution described in step S2 is used to encapsulate the spherical particles described in step S1 to obtain oval membrane / biocatalyst particles; the oval membrane / biocatalyst particles are uniformly mixed with the brittle dendritic connector from step S4, and after standing and draining, brittle dendritic connector / oval membrane / biocatalyst particles are obtained; the brittle dendritic connector / oval membrane / biocatalyst particles and the healing reactant are coated with an oval shell-shaped mixture using a pelletizing device, and then immediately subjected to light irradiation to obtain solidified oval shell membrane linkage material crack self-healing agent particles. The oval shell membrane linkage material crack self-healing agent is then protected in a sodium alginate protective solution. Subsequently, the oval shell membrane linkage material crack self-healing agent is separated from the sodium alginate protective solution, and the collected oval shell membrane linkage material crack self-healing agent is washed with a 90% anhydrous ethanol solution and air-dried.

14. The preparation method of the self-healing agent for cracks in the oval shell-membrane linkage material according to claim 13, characterized in that, Step S1 is as follows: Take 100 parts of biocatalyst and add 10-20 parts of water, and use a multi-functional granulator (1) to make the biocatalyst into spherical particles at a speed of 5g / time.

15. The preparation method of the self-healing agent for cracks in the oval shell-membrane linkage material according to claim 13, characterized in that, The acid leaching method described in step S2 is as follows: add 100-120 parts of fly ash to 220-260 parts of 1 mol / L hydrochloric acid and leach for 30 min.

16. The method for preparing the self-healing agent for cracks in the oval shell-membrane linkage material according to claim 13, characterized in that, In step S2, the mass ratio of solid residue, sodium carbonate and water is 10:(2~3):(20~30).

17. The method for preparing the self-healing agent for cracks in the oval shell-membrane linkage material according to claim 13, characterized in that, The reaction time in step S2 is 1~1.5 h.

18. The method for preparing the self-healing agent for cracks in the oval shell-membrane linkage material according to claim 13, characterized in that, Step S3 is as follows: add acrylic resin to bisphenol A type epoxy resin, heat in a water bath at 100~120℃ under magnetic stirring until the solid is completely dissolved, then add initiator and continue heating and stirring in a water bath for 20~30 min. After the sample cools down, let it stand in the dark to obtain an oval shell mixture.

19. The method for preparing the self-healing agent for cracks in the oval shell-membrane linkage material according to claim 13, characterized in that, The settling time in step S4 is 5 minutes, and the settling time again is 1 to 2 hours.

20. The method for preparing the self-healing agent for cracks in oval shell-membrane linkage materials according to any one of claims 13-19, characterized in that, The production apparatus used in the preparation method includes, in sequence according to the production process flow direction, a multi-functional granulator (1), a connecting pipe (2), an oval membrane solution storage tank (3), a first filter vibrating screen (4), a first conveyor belt (5), a drop pellet unit (60), a second filter vibrating screen (11), a second conveyor belt (12), and a storage tank (13). The discharge port of the multi-functional granulator (1) is connected to the inlet of the connecting pipe (2), and the outlet of the connecting pipe (2) is vertically arranged above the opening of the oval membrane solution storage tank (3). The first filter vibrating screen (4) is arranged below the outlet of the oval membrane solution storage tank (3), and one end of the first conveyor belt (5) is arranged below the first filter vibrating screen (4), and the other end is arranged above the inlet of the drop pellet unit (60). The drop pellet unit (60) includes a healing reaction agent storage tank (6), an oval shell mixture storage tank (7), and a T-tube (8). The drop pellet device (9) and the sodium alginate protective solution storage tank (10) are provided. The other end of the conveyor belt (5) is located above the inlet of the healing reaction agent storage tank (6). The outlet of the healing reaction agent storage tank (6) and the outlet of the oval shell mixture storage tank (7) are respectively connected to the two inlets of the T-tube (8). The outlet of the T-tube (8) is connected to the inlet of the drop pellet device (9). A metering pump (81) is provided in the T-tube pipeline between the healing reaction agent storage tank (6), the oval shell mixture storage tank (7) and the drop pellet device (9). The outlet of the drop pellet device (9) is vertically located above the inlet of the sodium alginate protective solution storage tank (10). The second filter vibrating screen (11) is located below the outlet of the sodium alginate protective solution storage tank (10). One end of the conveyor belt (12) is located below the second filter vibrating screen (11), and the other end is located above the inlet of the storage tank (13).

21. The application of the self-healing agent for cracks in oval shell-membrane linkage materials according to any one of claims 1 to 12, characterized in that, The steps for preparing self-healing cement are as follows: a. After wetting the self-healing agent for cracks in the oval shell membrane linkage material with water, mix it into cement powder for coating, then sieve, let stand, and dry to obtain the self-healing agent for cracks in the cement / oval shell membrane linkage material. b. Add the self-healing agent for cracks in the cement / oval shell membrane linkage material to a cement-based material to prepare self-healing cement.

22. The application of the self-healing agent for cracks in oval shell-membrane linkage materials according to claim 21, characterized in that, The mass ratio of cement powder to the self-healing agent for cracks in the oval shell membrane linkage material mentioned in step a is (10~12):(2.5~5).

23. The application of the self-healing agent for cracks in oval shell-membrane linkage materials according to claim 21, characterized in that, The particle size of the self-healing agent for cracks in the cement / oval shell membrane linkage material is 4~5 mm.

Images