Microcapsules, methods of making and using the same

Abstract

The application discloses a microcapsule and a preparation method and application thereof. The microcapsule comprises a capsule core and a composite capsule wall, the capsule core is wrapped in the composite capsule wall, the capsule core contains an active component, the composite capsule wall comprises an inner layer and an outer layer, the inner layer is a barium titanate resin composite wall, and the outer layer is a rubber material. The microcapsule has high strength, meets the road surface use requirement, and has good bonding strength with asphalt.

Description

Technical Field

[0001] This invention relates to the field of microcapsule materials technology, specifically to a microcapsule, its preparation method and application, and more specifically, to a microcapsule, its preparation method and the application of the microcapsule in pavement asphalt. Background Technology

[0002] During the long-term operation of asphalt pavements, the internal structure is susceptible to microscopic cracks and localized damage due to the combined effects of repeated vehicle loading and variable environmental factors. If timely and effective control measures are not implemented, these microscopic defects will gradually expand under continuous external stress, evolving into macroscopically visible cracks. Once cracks form, the accompanying water seepage will accelerate the deterioration of the pavement structure, severely shortening the actual service life of the road and causing it to fall far short of the expected design life.

[0003] Given the insidious nature of micro-cracks in asphalt pavements—they are often deeply embedded within the pavement—detection and identification are extremely challenging, making early manual intervention impractical. This predicament often leads to initial cracks being difficult to repair in a timely manner, potentially worsening into macro-cracks and ultimately causing structural damage and fracture.

[0004] Currently, most road repair strategies tend to intervene only after cracks have become obvious. While this delayed remedial measure can alleviate the problem, it inevitably disrupts traffic flow and is accompanied by additional costs such as human resources and material input.

[0005] Therefore, the introduction of microencapsulation technology has brought innovative solutions to the field of asphalt pavement repair. This technology encapsulates the repair agent within microcapsules and then integrates them into the asphalt material, achieving intelligent and pre-stressed repair of pavement cracks. Specifically, when microcracks develop in the pavement due to material aging or external forces, the stress concentration effect at the crack tip causes the passing microcapsules to rupture, releasing the built-in repair agent. Subsequently, guided by capillary forces, the repair agent flows along the crack path and penetrates to both sides of the crack, gradually filling and sealing it, thereby achieving the pavement's self-repair function.

[0006] It is worth noting that to ensure the effective application of microencapsulation technology in asphalt pavements, the mechanical properties of the microcapsules need to be carefully controlled. On the one hand, the microcapsules need to possess sufficient strength to withstand the mechanical forces during the asphalt mixture mixing process without breaking; on the other hand, their strength should not be too high, lest they be difficult to break when the pavement actually cracks, affecting the timely release of the repair agent and the repair effect. Therefore, the optimized application of microencapsulation technology requires comprehensive consideration of multiple factors to achieve its best performance in asphalt pavement repair.

[0007] CN117088635A discloses a nano-SiO2-enhanced self-healing microcapsule for asphalt pavement microcracks and its preparation method. The method provides a self-healing microcapsule with a silica-coated vegetable oil core material, which has a certain degree of self-healing ability. However, the microcapsules have insufficient bonding with the pavement and lack self-rupture performance.

[0008] In summary, a significant technical shortcoming exists in the current application of microencapsulation technology to asphalt pavement repair: the bonding strength between microcapsules and the asphalt matrix has not been adequately considered and optimized. This simplistic mixing method results in a lack of effective interfacial bonding between the microcapsules and the asphalt, making the microcapsules prone to separation from the asphalt during pavement service. This reduces the likelihood of the microcapsules effectively rupturing and releasing the repair agent when cracks occur, thus affecting the self-healing effect.

[0009] Furthermore, as the mainstay of highway construction, asphalt pavement construction still follows the traditional hot-mix hot-lay process. During this process, the asphalt at high temperatures undergoes a complex chemical reaction with oxygen in the air. This not only promotes the condensation and rearrangement of asphalt molecules, generating high-viscosity gums and asphaltenes, but also involves the thermal decomposition of asphalt molecules, releasing small-molecule volatile organic compounds, sulfides, and other substances, forming asphalt fumes. These harmful substances not only severely disrupt the ecological balance of the natural environment but also pose a potential threat to surrounding air quality and residents' health.

[0010] Given the fugitive emission characteristics of asphalt fumes during asphalt pavement construction and the extreme difficulty in controlling them, reducing asphalt fumes at the source and achieving a cleaner construction process has become an urgent task for promoting the green development of the transportation industry and fostering harmonious coexistence between socio-economic development and environmental protection. Therefore, exploring new low-emission asphalt materials, optimizing hot-mix asphalt paving processes, developing efficient technologies for collecting and treating pollutants such as small-molecule volatile organic compounds and sulfides, and promoting the innovation and upgrading of asphalt pavement construction technologies are key issues that urgently need to be addressed now and in the foreseeable future. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a microcapsule, its preparation method, and its application. The microcapsules of this invention not only possess high strength, meeting the requirements for road surface use, but also exhibit excellent bonding strength with asphalt.

[0012] One aspect of the present invention provides a microcapsule comprising a core and a composite capsule wall, wherein the core is encapsulated within the composite capsule wall and contains an active component, and the composite capsule wall comprises an inner layer and an outer layer, wherein the inner layer is a barium titanate resin composite wall and the outer layer is a rubber material.

[0013] Furthermore, the active component is a repair agent for self-repair of pavement cracks and / or an inhibitor for suppressing the release of asphalt fumes.

[0014] Furthermore, the repair agent used for self-repair of road surface cracks is rich in aromatic hydrocarbon components.

[0015] Furthermore, the aromatic hydrocarbon-rich component is selected from at least one of catalytic cracking slurry oil, reduced-pressure four-line extracted oil, furfural extracted oil, and waste lubricating oil.

[0016] Furthermore, the aromatic hydrocarbon content of the aromatic hydrocarbon-rich component is 45-65 wt%.

[0017] Furthermore, the inhibitor used to suppress the release of asphalt fumes is at least one of aldehyde compounds, ketone compounds, alcohol compounds, phenolic compounds, and ester compounds.

[0018] Further, the aldehyde compound is selected from at least one of aliphatic aldehydes with 7 or more carbon atoms and aromatic aldehydes with 6 or more carbon atoms, more preferably from at least one of p-methylbenzaldehyde, decanal, o-carboxybenzaldehyde, p-isopropylbenzaldehyde, cinnamaldehyde, p-hydroxybenzaldehyde, p-methoxybenzaldehyde, 2-methyl-3-(3,4-methylene-dioxyphenyl)propanal, 3,4-methylenedioxybenzaldehyde, 3-(4-isopropylphenyl)-2-methylpropanal, ethyl vanillin, phenylacetaldehyde, anisaldehyde, nonadien-2,6-aldehyde, 2,6-dimethyl-2,6-octadienal, vanillin, citronellol, neraldehyde, hydroxymethylpentylcyclohexene acetal, p-diethylaminobenzaldehyde, and undecenal.

[0019] Furthermore, the ketone compound is selected from at least one of aliphatic ketones with 8 or more carbon atoms and aromatic ketones with 8 or more carbon atoms, more preferably at least one of 6-methyl-3,5-heptadien-2-one, 2-undecanone, acetophenone, ionone, irisone, methyl ionone, damasone, and dihydrodamasone.

[0020] Further, the alcohol compound is an alcohol with more than 6 carbon atoms, more preferably at least one selected from cinnamyl alcohol, menthol, cis-3,7-dimethyl-2,6-octadienol, citronellol, geraniol, myrceneol, 2,6,10-trimethyl-2,6,10-dodecanetrien-12-ol, lavenderol, benzyl alcohol, 2-phenylethanol, dihydromyrceneol, tetrahydrogeraniol, and nerolidol.

[0021] Furthermore, the phenolic compound is a phenol with 6 or more carbon atoms, more preferably at least one of thymol, ethyl maltol, methyl maltol, 3-propenyl-6-ethoxyphenol, and isoeugenol.

[0022] Further, the ester compound is an ester with more than 7 carbon atoms, more preferably at least one of methyl salicylate, methyl cinnamate, ethyl cinnamate, ethyl phenylacetate, methyl phenylacetate, geraniol phenylacetate, phenylethyl phenylacetate, isoamyl phenylacetate, benzyl salicylate, p-methyl benzyl acetate, benzyl acetate, isobutyl benzoate, isoamyl salicylate, benzyl cinnamate, phenylethyl cinnamate, linaloyl formate, linaloyl acetate, linaloyl isobutyrate, menthyl acetate, terpineol acetate, and borneol acetate.

[0023] Furthermore, in the barium titanate resin composite wall, the mass ratio of resin to barium titanate is (0.1-8):1.

[0024] Furthermore, the barium titanate is a nanoparticle with a size of 20-100 nm.

[0025] Furthermore, the resin is at least one of melamine resin, urea-formaldehyde resin, and polymethyl methacrylate, preferably melamine resin.

[0026] Furthermore, the mass ratio of the core, inner layer, and outer layer is 1:(0.2-3):(0.2-3).

[0027] Furthermore, the rubber material is at least one of chlorinated rubber, styrene-butadiene rubber, and chloroprene rubber.

[0028] Furthermore, the size of the microcapsules is less than 50 μm, preferably less than 20 μm, and more preferably 3-15 μm.

[0029] A second aspect of the present invention provides a method for preparing the above-mentioned microcapsules, the method comprising:

[0030] (1) Preparation of barium titanate nanoparticles;

[0031] (2) The active components, barium titanate nanoparticles and water are mixed to form a Pickering emulsion;

[0032] (3) The Pickering emulsion is reacted with the resin prepolymer, and then filtered, washed and freeze-dried to obtain the pre-coated material;

[0033] (4) Mix the rubber material, solvent and the pre-coated material, then mix the resulting mixture with water, stir and heat to obtain microcapsules.

[0034] Furthermore, the method for preparing barium titanate nanoparticles in step (1) includes:

[0035] S1: Stir and mix the titanium precursor and solvent;

[0036] S2: Adjust the pH of the mixed solution obtained in S1 and stir until a titanium precursor sol is obtained;

[0037] S3: Mix the barium precursor with water;

[0038] S4: The titanium precursor sol obtained in S2 is mixed with the mixture obtained in S3 and reacted under stirring. After the reaction is completed, the mixture is filtered, washed, freeze-dried, and ground to obtain primary barium titanate nanoparticles.

[0039] S5: Primary barium titanate nanoparticles, surfactants and solvents are mixed and modified under stirring. After modification, the mixture is washed and freeze-dried to obtain barium titanate nanoparticles.

[0040] Further, in step S1, the titanium precursor is selected from at least one of tetraethyl titanate, n-propyl titanate, and tetrabutyl titanate, and is more preferably tetraethyl titanate.

[0041] Further, in step S1, the solvent is an alcohol compound with a boiling point >60°C, and the alcohol compound is an anhydrous alcohol compound, preferably at least one of methanol, butanediol, ethylene glycol, n-butanol, and ethanol, and more preferably anhydrous ethanol.

[0042] Furthermore, in step S1, the stirring temperature is 25-60℃; the stirring speed is 200-500 rpm; and the stirring time is 0.5-3 hours.

[0043] Further, in step S1, the mass ratio of the titanium precursor to the solvent is (1-20):1.

[0044] Further, in step S2, the pH of the S1 mixed solution is adjusted to pH = 9-12.

[0045] Further, in step S2, the pH of the S1 mixed solution is adjusted by adding an alkaline solution dropwise to the S1 solution. The alkaline solution is at least one of ammonia, sodium hydroxide solution, and potassium hydroxide solution.

[0046] Furthermore, in step S2, the stirring temperature is 25-60℃; the stirring speed is 200-500 rpm; and the stirring time is 0.5-3 hours.

[0047] Further, in step S3, the barium precursor is at least one of Ba(OH)2, Ba(OH)2·H2O, and Ba(OH)2·8H2O.

[0048] Further, in step S3, the barium precursor and water are added to the reaction vessel and stirred. Further, in step S3, the water is deionized water. The mass ratio of the barium precursor to deionized water is (0.5-4):1.

[0049] Furthermore, in step S3, the stirring temperature is 80-120℃; the stirring speed is 200-500 rpm; and the stirring time is 2-5 hours.

[0050] Further, in step S4, the molar ratio of the mixture obtained in S3 (based on barium) to the titanium precursor sol obtained in S2 (based on titanium) is 1:(0.5-5).

[0051] Furthermore, in step S4, the stirring speed is 200-500 rpm; the reaction temperature is 100-200℃; and the reaction time is 2-48 hours.

[0052] Furthermore, in step S4, the freeze-drying conditions are: vacuum drying for 4-8 hours at a temperature of -40°C to -20°C.

[0053] Furthermore, in step S4, the grinding specifically means grinding until there are no obvious lumps.

[0054] Furthermore, in step S5, the diameter of the barium titanate nanoparticles is 20-100 nm.

[0055] Further, in step S5, the surfactant is an anionic surfactant, preferably at least one of sodium dodecylbenzenesulfonate (SDBS), sodium dodecyl sulfate (SDS), and 2-morpholine ethanesulfonic acid, and more preferably sodium dodecylbenzenesulfonate.

[0056] Further, in step S5, the solvent is an aprotic solvent with a boiling point >100℃, preferably at least one of formamide, N,N-dimethylformamide, dimethylacetamide, and dimethylphosphoramide.

[0057] Further, in step S5, the mass ratio of the primary barium titanate nanoparticles to the surfactant is 1:(0.1-10), and the mass ratio of the solvent to the primary barium titanate nanoparticles is (5-50):1.

[0058] Furthermore, in step S5, the stirring speed is 200-500 rpm; the modification temperature is 70-180℃; and the modification time is 2-8 hours.

[0059] Furthermore, in step S5, the freeze-drying conditions are: vacuum drying for 4-8 hours at a temperature of -40°C to -20°C.

[0060] Further, in step (2), the mass ratio of the active component, barium titanate nanoparticles and water is 1:(0.1-0.8):(5-20).

[0061] Further, in step (2), the mixing is carried out under stirring, with a stirring speed of 200-500 rpm, a stirring time of 2-5 hours, and a temperature of 35-65℃.

[0062] Further, in step (3), before the Pickering emulsion reacts with the resin prepolymer, the pH value of the Pickering emulsion is adjusted to below 5, preferably 2-4. The reagent used to adjust the pH value can be a conventional inorganic acid solution, such as dilute hydrochloric acid.

[0063] Furthermore, in step (3), the reaction between the Pickering emulsion and the resin prepolymer is carried out under stirring. The stirring speed can be 400-800 rpm, the reaction temperature can be 60-90℃, and the time can be 1-5 hours.

[0064] Further, in step (3), the resin prepolymer can be one or more of melamine resin prepolymer, urea-formaldehyde resin prepolymer, and polymethyl methacrylate prepolymer. Preferably, the resin prepolymer is a melamine resin prepolymer.

[0065] Further, in step (3), the preparation method of the melamine resin prepolymer includes: mixing and dissolving melamine and formaldehyde solution with water, adjusting the pH value to 7.5-9.5, and then placing it in a constant temperature water bath at 60-90℃ and stirring at a speed of 400-800 rpm for 0.5-3.5 hours.

[0066] Furthermore, the concentration of the formaldehyde solution is 30-40 wt%.

[0067] Furthermore, the mass ratio of the melamine, the formaldehyde solution, and the water is 1:(2-3):(5-10).

[0068] Furthermore, in step (3), the freeze-drying conditions are: vacuum drying for 4-8 hours at a temperature of -40°C to -20°C.

[0069] Further, in step (4), the mass ratio of the rubber material, the solvent and water is 1:(10-200):(10-300).

[0070] Further, in step (4), the solvent is a volatile solvent selected from at least one of carbon tetrachloride, dichloromethane and trichloroethylene.

[0071] Further, in step (4), the stirring speed is 200-800 rpm. The temperature is raised until the solvent evaporates.

[0072] A third aspect of the present invention provides the application of the above-mentioned microcapsules in pavement asphalt, including:

[0073] The molten asphalt and the microcapsules are stirred under heating conditions to obtain an asphalt composition.

[0074] Furthermore, the content of the asphalt microcapsules is 0.1-2 parts by weight relative to 100 parts by weight of the asphalt.

[0075] Furthermore, the melting temperature of the asphalt is 138–178°C. The heating temperature is 138–178°C. The stirring speed is 500–1200 rpm, and the stirring time is 2–5 hours.

[0076] Furthermore, the penetration of the asphalt at 25°C is 30-210 1 / 10 mm.

[0077] Compared with the prior art, the present invention has the following advantages:

[0078] (1) The microcapsules of the present invention have a certain strength, which meets the requirements for road surface use. In the barium titanate resin composite wall, the barium titanate nanoparticles, due to their nano-size, can exist stably between the water and oil interface during the microcapsule synthesis process, and can further serve as a template agent for microcapsule synthesis to maintain the stability of the core material mixed droplets.

[0079] (2) In the microcapsule of the present invention, the barium titanate nanoparticles in the barium titanate resin composite wall are affected by high temperature, and the crystal axis will be distorted. Then, spontaneous polarization will occur without any external electric field, generating permanent electrodes, attracting the compounds released by asphalt under high temperature to the vicinity of the slow-release modified microcapsule, increasing the difficulty of volatilization of these compounds, thereby effectively reducing the impact of irritating gases released by asphalt pavement on the human body.

[0080] (3) The microcapsule of the present invention, as the rubber material of the outer capsule wall, can be effectively integrated with asphalt. The rubber material has good adhesion and forms a strong bond with the resin (especially melamine resin) as the inner capsule wall. When cracks appear in the asphalt pavement, it can effectively increase the probability of material cracking. The tearing of the outer capsule wall leads to the tearing of the inner capsule wall, releasing the repair agent and achieving the purpose of automatic repair. Detailed Implementation

[0081] The microcapsules, their preparation method, and applications according to the present invention are further illustrated below through examples. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0082] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0083] The sulfides in the asphalt flue gas described in this invention are tested by gas chromatography according to the standard GB / T 14678-1993, "Determination of hydrogen sulfide, methanethiol, dimethyl sulfide and dimethyl disulfide in air quality".

[0084] The volatile organic compounds in the asphalt fumes described in this invention are tested according to the standard HJ 734-2014, "Determination of Volatile Organic Compounds in Waste Gas from Stationary Sources: Solid Phase Adsorption-Thermal Desorption Gas Chromatography-Mass Spectrometry".

[0085] The asphalt fumes described in this invention were tested using the asphalt fumes enrichment and collection device described in Example 1 of Chinese Patent CN220912767U.

[0086] The self-healing ability of asphalt was investigated based on the asphalt pre-cut ductility test. During the test, following the ductility test method in JTGE20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", asphalt was first injected into a mold, and then a 4±0.1 mm cut was made in the middle of the ductility specimen using a blade. The specimen was then allowed to heal at 25℃ for 24 hours. The change in ductility before and after cutting was examined, and the degree of healing was calculated as: degree of healing = ductility after 24 hours of cutting / ductility before cutting.

[0087] Example 1

[0088] (1): Preparation of barium titanate nanoparticles:

[0089] S1: Weigh 15 parts by weight of tetraethyl titanate and 10 parts by weight of anhydrous ethanol and add them to a flask. Stir for 1 hour at 50°C and 400 rpm to obtain a titanium precursor solution.

[0090] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0091] S3: Add 16.3 parts by weight of Ba(OH)2·H2O and 20 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0092] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 130℃, stir at 300 rpm for 28 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0093] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 5 parts by weight of sodium dodecylbenzenesulfonate to 50 parts by weight of N,N-dimethylformamide. Modify by stirring at 300 rpm for 6 hours at 150°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size 40-70 nm).

[0094] (2): Mix 1 part by weight of catalytic cracking oil slurry (aromatic content of 50 wt%) with 8.5 parts by weight of deionized water at 60°C, add 0.5 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0095] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0096] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0097] (4): Dissolve 0.2 parts by weight of chlorinated rubber in 3 parts by weight of dichloromethane, add the pre-coating material prepared in (3), and mix thoroughly. Add the resulting mixture to 6 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules. The size is 7.3-10.8 μm, and the mass ratio of the core, inner layer and outer layer in the microcapsule is 1:1.3:1.8.

[0098] 1.6 parts by weight of the microcapsules obtained in step (4) were added to 100 parts by weight of molten straight-run asphalt at 150°C (penetration at 25°C 93 1 / 10 mm). The mixture was stirred at 800 rpm for 3 hours under heating conditions at 150°C to obtain self-healing asphalt.

[0099] Example 2

[0100] (1): Preparation of barium titanate nanoparticles:

[0101] S1: Weigh 10 parts by weight of tetraethyl titanate and 6 parts by weight of n-butanol and add them to a flask. Stir for 1 hour at 50°C and 400 rpm to obtain a titanium precursor solution.

[0102] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0103] S3: Add 11 parts by weight of Ba(OH)2·H2O and 15 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0104] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 130℃, stir at 300 rpm for 28 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0105] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 5 parts by weight of sodium dodecylbenzenesulfonate to 50 parts by weight of N,N-dimethylformamide. Modify by stirring at 300 rpm for 6 hours at 150°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size 40-70 nm).

[0106] (2): 1 part by weight of furfural extract oil (aromatic content of 53 wt.%) was mixed with 8.5 parts by weight of deionized water at 60°C, and 0.5 parts by weight of barium titanate nanoparticles were added. The mixture was stirred at 400 rpm for 4 hours to obtain Pickering emulsion.

[0107] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0108] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0109] (4): Dissolve 0.2 parts by weight of chlorinated rubber in 3 parts by weight of dichloromethane, add the pre-coating material prepared in (3), and mix thoroughly. Add the resulting mixture to 6 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules. The size is 7.3-10.8 μm, and the mass ratio of the core, inner layer and outer layer in the microcapsule is 1:1.3:1.8.

[0110] 1.6 parts by weight of the microcapsules obtained in step (4) were added to 100 parts by weight of molten straight-run asphalt at 150°C (penetration at 25°C 93 1 / 10 mm). The mixture was stirred at 800 rpm for 3 hours under heating conditions at 150°C to obtain self-healing asphalt.

[0111] Example 3

[0112] (1): Preparation of barium titanate nanoparticles:

[0113] S1: Weigh 11.5 parts by weight of tetraethyl titanate and 7 parts by weight of ethylene glycol and add them to a flask. Stir for 1 hour at 55°C and 400 rpm to obtain a titanium precursor solution.

[0114] S2: Slowly add 10wt% ammonia water to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 55℃ to obtain titanium precursor sol.

[0115] S3: Add 12.5 parts by weight of Ba(OH)2·H2O and 15 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0116] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 150℃, stir at 300 rpm for 24 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0117] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 4 parts by weight of sodium dodecylbenzenesulfonate to 50 parts by weight of N,N-dimethylformamide. Modify by stirring at 300 rpm for 6 hours at 150°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size 40-70 nm).

[0118] (2): Mix 0.8 parts by weight of catalytic cracking oil slurry (aromatic content of 50 wt.%) with 8.7 parts by weight of deionized water at 60°C, add 0.5 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0119] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0120] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0121] (4): Dissolve 0.2 parts by weight of chlorinated rubber in 3 parts by weight of dichloromethane, add the pre-coating material prepared in (3), and mix thoroughly. Add the resulting mixture to 6 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules. The size is 6.8-10.3 μm, and the mass ratio of the core, inner layer and outer layer in the microcapsule is 1:1.6:2.2.

[0122] 1.6 parts by weight of the microcapsules obtained in step (4) were added to 100 parts by weight of molten straight-run asphalt at 150°C (penetration at 25°C 93 1 / 10 mm). The mixture was stirred at 800 rpm for 3 hours under heating conditions at 150°C to obtain self-healing asphalt.

[0123] Example 4

[0124] (1): Preparation of barium titanate nanoparticles:

[0125] S1: Weigh 13 parts by weight of tetraethyl titanate and 8 parts by weight of butanediol and add them to a flask. Stir for 1 hour at 50°C and 400 rpm to obtain a titanium precursor solution.

[0126] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0127] S3: Add 14 parts by weight of Ba(OH)2·H2O and 14 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0128] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 140℃, stir at 300 rpm for 26 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0129] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 3 parts by weight of 2-morpholine ethanesulfonic acid to 30 parts by weight of N,N-dimethylformamide. Modify by stirring at 300 rpm for 6 hours at 140°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size of 40-70 nm).

[0130] (2): 1 part by weight of catalytic cracking oil slurry (aromatic content of 50 wt.%) was mixed with 8.5 parts by weight of deionized water at 60°C, and 0.5 parts by weight of barium titanate nanoparticles were added. The mixture was stirred at 400 rpm for 4 hours to obtain Pickering emulsion.

[0131] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0132] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0133] (4): Dissolve 0.2 parts by weight of chloroprene rubber in 2 parts by weight of trichloroethylene, add the pre-coating material prepared in (3), and mix thoroughly. Add the resulting mixture to 6 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules. The size is 7.3-10.8 μm, and the mass ratio of the core, inner layer and outer layer in the microcapsule is 1:1.3:1.8.

[0134] 1.6 parts by weight of the microcapsules obtained in step (4) were added to 100 parts by weight of molten straight-run asphalt at 150°C (penetration at 25°C 93 1 / 10 mm). The mixture was stirred at 800 rpm for 3 hours under heating conditions at 150°C to obtain self-healing asphalt.

[0135] Example 5

[0136] (1): Preparation of barium titanate nanoparticles:

[0137] S1: Weigh 8.3 parts by weight of tetraethyl titanate and 6 parts by weight of methanol and add them to a flask. Stir for 1 hour at 35°C and 300 rpm to obtain a titanium precursor solution.

[0138] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 35℃ to obtain titanium precursor sol.

[0139] S3: Add 9 parts by weight of Ba(OH)2·H2O and 12 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0140] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 130℃, stir at 300 rpm for 28 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0141] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 6 parts by weight of sodium dodecyl sulfate to 50 parts by weight of N,N-dimethylformamide. Modify by stirring at 300 rpm for 3 hours at 130°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size 40-70 nm).

[0142] (2): 1 part by weight of catalytic cracking oil slurry (aromatic content of 50 wt.%) was mixed with 8.5 parts by weight of deionized water at 60°C, and 0.5 parts by weight of barium titanate nanoparticles were added. The mixture was stirred at 400 rpm for 4 hours to obtain Pickering emulsion.

[0143] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0144] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0145] (4): Dissolve 0.15 parts by weight of chlorinated rubber in 3 parts by weight of dichloromethane, add the pre-coating material prepared in (3), and mix thoroughly. Add the resulting mixture to 6 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules. The size is 6.5-9 μm, and the mass ratio of the core, inner layer and outer layer in the microcapsule is 1:1.3:1.35.

[0146] 1.6 parts by weight of the microcapsules obtained in step (4) were added to 100 parts by weight of molten straight-run asphalt at 150°C (penetration at 25°C 93 1 / 10 mm). The mixture was stirred at 800 rpm for 3 hours under heating conditions at 150°C to obtain self-healing asphalt.

[0147] Comparative Example 1

[0148] 100 parts by weight of straight-run asphalt molten at 150℃ (penetration at 25℃ 93 1 / 10 mm) were stirred at 800 rpm for 3 hours under heating conditions at 150℃ to obtain asphalt control samples.

[0149] Comparative Example 2

[0150] (1): Preparation of barium titanate nanoparticles: Same as in Example 1;

[0151] (2): 1 part by weight of catalytic cracking oil slurry (aromatic content of 50 wt.%) was mixed with 8.5 parts by weight of deionized water at 60°C, and 0.5 parts by weight of barium titanate nanoparticles were added. The mixture was stirred at 400 rpm for 4 hours to obtain Pickering emulsion.

[0152] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0153] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain microcapsules.

[0154] Add 1.6 parts by weight of the microcapsules obtained in step (3) to 100 parts by weight of molten straight-run asphalt at 150°C (penetration at 25°C 93 1 / 10 mm), and stir at 800 rpm for 3 hours under heating conditions at 150°C to obtain self-healing asphalt.

[0155] Comparative Example 3

[0156] 1.6 parts by weight of catalytic cracking slurry were added to 100 parts by weight of straight-run asphalt molten at 150°C (penetration at 25°C 93 1 / 10 mm), and stirred at 800 rpm for 3 hours under heating conditions at 150°C to obtain self-healing asphalt.

[0157] Test Example 1

[0158] The ductility of the asphalt sample before and after cutting was tested, and the data are shown in Table 1.

[0159] Table 1

[0160] 10 °C elongation / cm healing degree / % Example 1 104 47.32 Example 2 102 45.88 Example 3 101 42.57 Example 4 103 45.41 Example 5 99 40.21 Comparative Example 1 106 15.14 Comparative Example 2 89 28.85 Comparative Example 3 119 18.56

[0161] Example 6

[0162] (1): Preparation of barium titanate nanoparticles:

[0163] S1: Weigh 16 parts by weight of tetraethyl titanate and 9 parts by weight of anhydrous ethanol and add them to a flask. Stir for 1 hour at 50°C and 400 rpm to obtain a titanium precursor solution.

[0164] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0165] S3: Add 13.5 parts by weight of Ba(OH)2·H2O and 15 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0166] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 130℃, stir at 300 rpm for 28 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0167] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 4 parts by weight of sodium dodecylbenzenesulfonate to 45 parts by weight of formamide. Modify by stirring at 200 rpm for 5.5 hours at 140°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size of 40-60 nm).

[0168] (2): Mix 1 part by weight of cinnamaldehyde with 8.5 parts by weight of deionized water at 60°C, add 0.5 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0169] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0170] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0171] (4): Dissolve 0.08 parts by weight of chlorinated rubber in 2 parts by weight of dichloromethane, add the pre-coating material obtained in step (3), and mix thoroughly. Add the resulting mixture to 5 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules with a size of 5.4-7.4 μm. The mass ratio of the core, inner layer, and outer layer in the microcapsules is 1:1.3:0.73.

[0172] Add 0.8 parts by weight of the microcapsules obtained in step (4) to 100 parts by weight of molten straight-run asphalt (25°C penetration 95 1 / 10 mm) at 140°C, and stir at 800 rpm for 5 hours under heating conditions at 140°C to obtain environmentally friendly asphalt.

[0173] Example 7

[0174] (1): Preparation of barium titanate nanoparticles:

[0175] S1: Weigh 14 parts by weight of tetraethyl titanate and 10 parts by weight of butanediol and add them to a flask. Stir at 50°C and 400 rpm for 1 hour to obtain a titanium precursor solution.

[0176] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0177] S3: Add 12 parts by weight of Ba(OH)2·H2O and 12 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0178] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 140℃, stir at 350 rpm for 26 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0179] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 5 parts by weight of sodium dodecylbenzenesulfonate to 45 parts by weight of formamide. Modify by stirring at 200 rpm for 5.5 hours at 140°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size 40-60 nm).

[0180] (2): Mix 1 part by weight of benzyl salicylate with 8.5 parts by weight of deionized water at 60°C, add 0.5 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0181] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0182] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0183] (4): Dissolve 0.08 parts by weight of chlorinated rubber in 2 parts by weight of dichloromethane, add the pre-coating material obtained in step (3), and mix thoroughly. Add the resulting mixture to 5 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules with a size of 5.4-7.4 μm. The mass ratio of the core, inner layer, and outer layer in the microcapsules is 1:1.3:0.73.

[0184] Add 0.8 parts by weight of the microcapsules obtained in step (4) to 100 parts by weight of molten straight-run asphalt (25°C penetration 95 1 / 10 mm) at 140°C, and stir at 800 rpm for 5 hours under heating conditions at 140°C to obtain environmentally friendly asphalt.

[0185] Example 8

[0186] (1): Preparation of barium titanate nanoparticles:

[0187] S1: Weigh 12.5 parts by weight of tetraethyl titanate and 8 parts by weight of n-butanol and add them to a flask. Stir for 1 hour at 50°C and 400 rpm to obtain a titanium precursor solution.

[0188] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0189] S3: Add 10 parts by weight of Ba(OH)2·H2O and 8 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 3 hours at 90°C.

[0190] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 160℃, stir at 300 rpm for 22 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0191] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 6 parts by weight of sodium dodecyl sulfate to 45 parts by weight of formamide. Modify by stirring at 200 rpm for 5.5 hours at 140°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size 40-60 nm).

[0192] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 4 parts by weight of sodium dodecylbenzenesulfonate to 45 parts by weight of formamide. Modify by stirring at 200 rpm for 5.5 hours at 140°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size of 40-60 nm).

[0193] (2): Mix 0.6 parts by weight of cinnamaldehyde with 8.9 parts by weight of deionized water at 60°C, add 0.5 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0194] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0195] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0196] (4): Dissolve 0.08 parts by weight of chlorinated rubber in 2 parts by weight of dichloromethane, add the pre-coating material obtained in step (3), and mix thoroughly. Add the resulting mixture to 5 parts by weight of water, stir at 500 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules with a size of 4.8-6.5 μm. The mass ratio of the core, inner layer, and outer layer in the microcapsules is 1:2:1.2.

[0197] Add 0.8 parts by weight of the microcapsules obtained in step (4) to 100 parts by weight of molten straight-run asphalt (25°C penetration 95 1 / 10 mm) at 140°C, and stir at 800 rpm for 5 hours under heating conditions at 140°C to obtain environmentally friendly asphalt.

[0198] Example 9

[0199] (1): Preparation of barium titanate nanoparticles:

[0200] S1: Weigh 10 parts by weight of tetraethyl titanate and 8 parts by weight of methanol and add them to a flask. Stir for 1 hour at 35°C and 300 rpm to obtain a titanium precursor solution.

[0201] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 35℃ to obtain titanium precursor sol.

[0202] S3: Add 8.3 parts by weight of Ba(OH)2·H2O and 8.3 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0203] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 130℃, stir at 300 rpm for 28 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0204] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 4 parts by weight of sodium dodecylbenzenesulfonate to 45 parts by weight of formamide. Modify by stirring at 200 rpm for 5.5 hours at 140°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size of 40-60 nm).

[0205] (2): Mix 1 part by weight of cinnamaldehyde with 8.5 parts by weight of deionized water at 60°C, add 0.5 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0206] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0207] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.75 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0208] (4): Dissolve 0.08 parts by weight of chlorinated rubber in 2 parts by weight of dichloromethane, add the pre-coating material obtained in step (3), and mix thoroughly. Add the resulting mixture to 5 parts by weight of water, stir at 400 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules with a size of 6.3-8.5 μm. The mass ratio of the core, inner layer and outer layer in the microcapsule is 1:1.65:0.73.

[0209] Add 0.8 parts by weight of the microcapsules obtained in step (4) to 100 parts by weight of molten straight-run asphalt (25°C penetration 95 1 / 10 mm) at 140°C, and stir at 800 rpm for 5 hours under heating conditions at 140°C to obtain environmentally friendly asphalt.

[0210] Example 10

[0211] (1): Preparation of barium titanate nanoparticles:

[0212] S1: Weigh 8 parts by weight of tetraethyl titanate and 5 parts by weight of anhydrous ethanol and add them to a flask. Stir for 1 hour at 50°C and 400 rpm to obtain a titanium precursor solution.

[0213] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0214] S3: Add 6 parts by weight of Ba(OH)2·H2O and 4 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0215] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 150℃, stir at 300 rpm for 24 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0216] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 8 parts by weight of 2-morpholine ethanesulfonic acid to 45 parts by weight of formamide. Modify by stirring at 200 rpm for 6 hours at 150°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size of 40-60 nm).

[0217] (2): Mix 1 part by weight of cinnamaldehyde with 8.7 parts by weight of deionized water at 60°C, add 0.3 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0218] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0219] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0220] (4): Dissolve 0.08 parts by weight of chlorinated rubber in 2 parts by weight of dichloromethane, add the pre-coating material obtained in step (3), and mix thoroughly. Add the resulting mixture to 5 parts by weight of water, stir at 450 rpm, and raise the temperature until the solvent evaporates to obtain microcapsules with a size of 5.2-7.1 μm. The mass ratio of the core, inner layer, and outer layer in the microcapsules is 1:1.05:0.73.

[0221] Add 0.8 parts by weight of the microcapsules obtained in step (4) to 100 parts by weight of molten straight-run asphalt (25°C penetration 95 1 / 10 mm) at 140°C, and stir at 800 rpm for 5 hours under heating conditions at 140°C to obtain environmentally friendly asphalt.

[0222] Comparative Example 4

[0223] 100 parts by weight of straight-run asphalt (penetration of 95 1 / 10 mm at 25℃) molten at 140℃ were stirred at 800 rpm for 5 hours under heating conditions at 140℃ to obtain an asphalt control sample.

[0224] Comparative Example 5

[0225] Add 0.8 parts by weight of cinnamaldehyde to 100 parts by weight of molten straight-run asphalt (penetration of 95 1 / 10 mm at 25°C) at 140°C, and stir at 800 rpm for 5 hours under heating conditions at 140°C to obtain environmentally friendly asphalt.

[0226] Comparative Example 6

[0227] (1): Preparation of barium titanate nanoparticles:

[0228] S1: Weigh 16 parts by weight of tetraethyl titanate and 9 parts by weight of anhydrous ethanol and add them to a flask. Stir for 1 hour at 50°C and 400 rpm to obtain a titanium precursor solution.

[0229] S2: Slowly add 10wt% ammonia to the S1 solution until the pH of the reaction system is 10, and continue stirring at 400 rpm for 1 hour at 50℃ to obtain titanium precursor sol.

[0230] S3: Add 13.5 parts by weight of Ba(OH)2·H2O and 15 parts by weight of deionized water to the reactor, and heat and stir at 400 rpm for 2 hours at 90°C.

[0231] S4: Add the sol obtained in S2 to the reaction vessel in S3, close the reaction vessel lid, heat to 130℃, stir at 300 rpm for 28 hours, then filter and wash the solid powder in the reaction system, and vacuum dry at -30℃ for 5 hours. After grinding until there are no obvious lumps in the system, the primary barium titanate nanoparticles are obtained.

[0232] S5: Add 1 part by weight of the primary barium titanate nanoparticles obtained in step S4 and 4 parts by weight of sodium dodecylbenzenesulfonate to 45 parts by weight of formamide. Modify by stirring at 200 rpm for 5.5 hours at 140°C. Then filter and wash the bottom solid powder and vacuum dry it at -30°C for 5 hours to obtain barium titanate nanoparticles (particle size of 40-60 nm).

[0233] (2): Mix 1 part by weight of cinnamaldehyde with 8.5 parts by weight of deionized water at 60°C, add 0.5 parts by weight of barium titanate nanoparticles, and stir at 400 rpm for 4 hours to obtain Pickering emulsion.

[0234] (3): Dissolve 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt% and 7 parts by weight of deionized water in a three-necked flask, adjust the pH value to 8.5, and then place it in a constant temperature water bath at 65°C and stir at 800 rpm for 0.5 hours to obtain melamine resin prepolymer.

[0235] Add dilute hydrochloric acid dropwise to 1 part by weight of Pickering emulsion to adjust the pH value to 2. Slowly add 0.5 parts by weight of the prepared melamine resin prepolymer to the Pickering emulsion, stir at 700 rpm, and react at 75°C for 2 hours. Then filter and wash the solid powder in the reaction system, and vacuum dry at -30°C for 5 hours to obtain the pre-coated material.

[0236] Add 0.8 parts by weight of the pre-coating material obtained in step (3) to 100 parts by weight of molten straight-run asphalt at 140℃ (penetration of 95 1 / 10 mm at 25℃), and stir at 800 rpm for 5 hours under heating conditions at 140℃ to obtain environmentally friendly asphalt.

[0237] Test Example 2

[0238] Sulfides and volatile organic compounds are the main causes of the pungent odor of asphalt fumes. Asphalt samples prepared in Examples 6-10 and Comparative Examples 4-6 were stored at 130°C for 4 days. Then, an equal mass of the stored asphalt was transferred to an asphalt fume enrichment and collection device, where fume enrichment was carried out at 140°C for 6 hours. After enrichment, the gas in the sealed container was extracted and tested. The data obtained are shown in Table 2 below.

[0239] Table 2

[0240]

[0241] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A microcapsule, characterized in that, The microcapsule includes a core and a composite capsule wall. The core is encapsulated within the composite capsule wall and contains an active component. The composite capsule wall includes an inner layer and an outer layer. The inner layer is a barium titanate resin composite wall, and the outer layer is a rubber material.

2. The microcapsule according to claim 1, characterized in that, The active component is a repair agent for self-repair of pavement cracks and / or an inhibitor for suppressing the release of asphalt fumes; the repair agent for self-repair of pavement cracks is an aromatic hydrocarbon-rich component; the inhibitor for suppressing the release of asphalt fumes is at least one of aldehyde compounds, ketone compounds, alcohol compounds, phenolic compounds and ester compounds.

3. The microcapsule according to claim 2, characterized in that, The aldehyde compound is selected from at least one of aliphatic aldehydes with 7 or more carbon atoms and aromatic aldehydes with 6 or more carbon atoms, more preferably from at least one of p-methylbenzaldehyde, decanal, o-carboxybenzaldehyde, p-isopropylbenzaldehyde, cinnamaldehyde, p-hydroxybenzaldehyde, p-methoxybenzaldehyde, 2-methyl-3-(3,4-methylene-dioxyphenyl)propanal, 3,4-methylenedioxybenzaldehyde, 3-(4-isopropylphenyl)-2-methylpropanal, ethyl vanillin, phenylacetaldehyde, anisaldehyde, nonadien-2,6-aldehyde, 2,6-dimethyl-2,6-octadienal, vanillin, citronellol, neraldehyde, hydroxymethylpentylcyclohexene acetal, p-diethylaminobenzaldehyde, and undecenal; And / or, the ketone compound is selected from at least one of aliphatic ketones with 8 or more carbon atoms and aromatic ketones with 8 or more carbon atoms, more preferably at least one of 6-methyl-3,5-heptadien-2-one, 2-undecanone, acetophenone, ionone, irisone, methyl ionone, damasone and dihydrodamasone. And / or, the alcohol compound is an alcohol with more than 6 carbon atoms, more preferably at least one of cinnamyl alcohol, menthol, cis-3,7-dimethyl-2,6-octadienol, citronellol, geraniol, myrceneol, 2,6,10-trimethyl-2,6,10-dodecanetrien-12-ol, lavenderol, benzyl alcohol, 2-phenylethanol, dihydromyrceneol, tetrahydrogeraniol, and nerolidol; And / or, the phenolic compound is a phenol with 6 or more carbon atoms, more preferably at least one of thymol, ethyl maltol, methyl maltol, 3-propenyl-6-ethoxyphenol and isoeugenol; And / or, the ester compound is an ester with more than 7 carbon atoms, more preferably at least one of methyl salicylate, methyl cinnamate, ethyl cinnamate, ethyl phenylacetate, methyl phenylacetate, geraniol phenylacetate, phenylethyl phenylacetate, isoamyl phenylacetate, benzyl salicylate, p-methyl benzyl acetate, benzyl acetate, isobutyl benzoate, isoamyl salicylate, benzyl cinnamate, phenylethyl cinnamate, linaloyl formate, linaloyl acetate, linaloyl isobutyrate, menthyl acetate, terpineol acetate, and borneol acetate.

4. The microcapsule according to claim 1, characterized in that, In the barium titanate resin composite wall, the mass ratio of resin to barium titanate is (0.1-8):1; And / or, the barium titanate is a nanoparticle with a size of 20-100 nm; And / or, the resin is at least one of melamine resin, urea-formaldehyde resin and polymethyl methacrylate, preferably melamine resin; And / or, the rubber material is at least one of chlorinated rubber, styrene-butadiene rubber, and chloroprene rubber.

5. The microcapsule according to claim 1, characterized in that, The mass ratio of the core, inner layer, and outer layer is 1:(0.2-3):(0.2-3).

6. The microcapsule according to claim 1, characterized in that, The size of the microcapsules is less than 50 μm, preferably less than 20 μm, and more preferably 3-15 μm.

7. A method for preparing the microcapsules according to any one of claims 1-6, comprising: (1) Preparation of barium titanate nanoparticles; (2) The active components, barium titanate nanoparticles and water are mixed to form a Pickering emulsion; (3) The Pickering emulsion is reacted with the resin prepolymer, and then filtered, washed and freeze-dried to obtain the pre-coated material; (4) Mix the rubber material, solvent and the pre-coated material, then mix the resulting mixture with water, stir and heat to obtain microcapsules.

8. The method according to claim 7, characterized in that, Step (1) of preparing barium titanate nanoparticles includes: S1: Stir and mix the titanium precursor and solvent; S2: Adjust the pH of the mixed solution obtained in S1 and stir until a titanium precursor sol is obtained; S3: Mix the barium precursor with water; S4: The titanium precursor sol obtained in S2 is mixed with the mixture obtained in S3 and reacted under stirring. After the reaction is completed, the mixture is filtered, washed, freeze-dried, and ground to obtain primary barium titanate nanoparticles. S5: Primary barium titanate nanoparticles, surfactants and solvents are mixed and modified under stirring. After modification, the mixture is washed and freeze-dried to obtain barium titanate nanoparticles.

9. The method according to claim 8, characterized in that, In step S1, the titanium precursor is selected from at least one of tetraethyl titanate, n-propyl titanate, and tetrabutyl titanate. And / or, in step S1, the solvent is an alcohol compound with a boiling point >60°C, and the alcohol compound is an anhydrous alcohol compound, preferably at least one of methanol, butanediol, ethylene glycol, n-butanol, and ethanol; And / or, in step S1, the stirring temperature is 25-60℃; the stirring speed is 200-500 rpm; and the stirring time is 0.5-3 hours. And / or, in step S1, the mass ratio of the titanium precursor to the solvent is (1-20):

1.

10. The method according to claim 8, characterized in that, In step S2, the pH of the S1 mixed solution is adjusted to pH = 9-12; And / or, in step S2, the stirring temperature is 25-60℃; the stirring speed is 200-500 rpm; and the stirring time is 0.5-3 hours.

11. The method according to claim 8, characterized in that, In step S3, the barium precursor is at least one of Ba(OH)2, Ba(OH)2·H2O, and Ba(OH)2·8H2O. And / or, in step S3, the stirring temperature is 80-120℃; the stirring speed is 200-500 rpm; and the stirring time is 2-5 hours.

12. The method according to claim 8, characterized in that, In step S4, the molar ratio of the mixture obtained in S3 (based on barium) to the titanium precursor sol obtained in S2 (based on titanium) is 1:(0.5-5). And / or, the stirring speed is 200-500 rpm; the reaction temperature is 100-200℃; and the reaction time is 2-48 hours. And / or, in step S4, the freeze-drying conditions are: vacuum drying for 4-8 hours at a temperature of -40°C to -20°C.

13. The method according to claim 8, characterized in that, In step S5, the diameter of the barium titanate nanoparticles is 20-100 nm; And / or, in step S5, the surfactant is an anionic surfactant, preferably at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and 2-morpholine ethanesulfonic acid; And / or, in step S5, the solvent is an aprotic solvent with a boiling point >100℃, preferably at least one of formamide, N,N-dimethylformamide, dimethylacetamide, and dimethylphosphoramide; And / or, in step S5, the stirring speed is 200-500 rpm; The modification temperature is 70-180℃, and the modification time is 2-8 hours; And / or, in step S5, the freeze-drying conditions are: vacuum drying for 4-8 hours at a temperature of -40°C to -20°C.

14. The method according to claim 7, characterized in that, In step (2), the mass ratio of the active component, barium titanate nanoparticles and water is 1:(0.1-0.8):(5-20); And / or, in step (2), the mixing is carried out under stirring, the stirring speed is 200-500 rpm, the stirring time is 2-5 hours, and the temperature is 35-65℃.

15. The method according to claim 7, characterized in that, In step (3), before the Pickering emulsion reacts with the resin prepolymer, the pH value of the Pickering emulsion is adjusted to below 5, preferably 2-4; And / or, in step (3), the reaction between the Pickering emulsion and the resin prepolymer is carried out under stirring at a speed of 400-800 rpm, a reaction temperature of 60-90°C, and a time of 1-5 hours. And / or, in step (3), the freeze-drying conditions are: vacuum drying for 4-8 hours at a temperature of -40°C to -20°C.

16. The method according to claim 7, characterized in that, In step (4), the mass ratio of the rubber material, the solvent, and the water is 1:(10-200):(10-300); And / or, in step (4), the solvent is a volatile solvent selected from at least one of carbon tetrachloride, dichloromethane and trichloroethylene; And / or, in step (4), the stirring speed is 200-800 rpm.

17. The application of the microcapsules according to any one of claims 1-6 or the microcapsules prepared by the method according to any one of claims 7-16 in pavement asphalt, comprising: The molten asphalt and the microcapsules are stirred under heating conditions to obtain an asphalt composition.

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