Phase-change ice-inhibiting and self-repairing double-layer microsphere as well as preparation method and application thereof

Abstract

The invention discloses phase-change ice-inhibiting and self-repairing double-layer microspheres as well as a preparation method and application thereof, and belongs to the technical field of road engineering materials. According to the phase-change ice-inhibiting and self-repairing double-layer microsphere, a urethane thermal regulation shell sphere wall prepolymer serves as a shell, a self-healing core microsphere serves as an inner core, and a cold-resistant ice-inhibiting agent is clamped between the shell and the inner core, so that a double-layer microsphere structure is formed. Solid-solid phase change and solid-liquid phase change are ingeniously combined, the polyurethane capsule wall is endowed with a phase change function, and a double-layer protection mechanism integrating ice suppression, temperature control and self-repairing functions is comprehensively formed. The pavement crack caused by temperature stress is relieved through phase change self-temperature regulation in severe cold or summer weather, and when the phase change effect fails or cracks occur, the pavement can be timely broken to release a regenerant to repair the cracks. The microspheres can be widely applied to spraying and mixing emulsified asphalt or paving cold-mixed asphalt, can also be used for functional asphalt coatings, provides multiple protection functions of ice inhibition and heat insulation, and enhances the durability and adaptability of pavements.

Description

Technical Field

[0001] The present invention belongs to the technical field of road engineering materials, and particularly relates to a phase change ice suppression and self-repair double-layer microsphere, a preparation method thereof, and an application thereof. Background Art

[0002] With the acceleration of the urbanization process, the overall level of infrastructure construction such as roads, bridges, and urban construction has been leapfrogged. At the same time, environmental problems have also intensified. The extensive paving of cement and asphalt roads, gravel bricks, etc. in cities has weakened the water cycle efficiency while enhancing urban functions, resulting in the aggravation of the urban heat island effect. High-temperature and sweltering weather is common in summer, and extreme ice and snow weather is becoming more and more frequent in winter. This not only has a great impact on people's daily lives, but also brings problems such as high-temperature arching, low-temperature cracking, snow accumulation and icing of roads, which not only shortens the service life of roads, but also poses great potential safety hazards to road traffic safety, posing a severe challenge to the stability and safety of road infrastructure.

[0003] For a long time, scholars have been committed to studying the performance of various road functional maintenance materials, mainly focusing on fields such as surface micro-nano structure design, material functional modification, and the development of multifunctional composite materials, in order to inhibit problems such as road icing, cracking, and high-temperature diseases. For example, microcapsule technology, as an innovative material solution, has been widely used in the field of road maintenance engineering in recent years. For example, Patent CN111303646A discloses a modified asphalt that realizes self-temperature regulation based on phase change microcapsules. By incorporating phase change microcapsules into asphalt mixtures, the road surface is given the ability to cool down under high-temperature conditions, thereby alleviating high-temperature disease problems. Patent CN117986875A discloses an asphalt pavement rubber material with both self-stress ice-breaking and phase change snow-melting functions and a preparation method thereof. It uses graphene-vinyl MQ silicone resin composite wall material phase change microcapsules to make it have both self-stress ice-breaking and phase change snow-melting functions, providing a solution to the ice and snow problems on roads. However, the existing technologies still have limitations. Although the phase change microcapsules described in the above two disclosed patents have corresponding effects, they have a single function. Although they can delay road surface cracking at low temperatures, the temperature range is relatively narrow. While suppressing ice at low temperatures or delaying cracking, they cannot repair road surface cracks; they also lack effective functions to cope with sweltering weather under high-temperature conditions. Therefore, it is urgent to invent a road surface maintenance material with continuous wide-temperature range phase change, integrating ice suppression, temperature reduction, resistance to road surface cracking, and having the function of road surface self-repair. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a phase change ice suppression and self-repair double-layer microsphere, a preparation method thereof, and an application thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the purposes of the present invention is to provide a phase change ice suppression and self-healing double-layer microsphere. The phase change ice suppression and self-healing double-layer microsphere uses a urethane thermal regulation outer shell wall prepolymer as the outer shell, a self-healing core microsphere as the inner core, and an anti-cold ice suppressant is sandwiched between the outer shell and the inner core to form a double-layer microsphere structure. In the double-layer microsphere structure, the thickness ratio of the outer shell, the anti-cold ice suppressant, and the self-healing core microsphere is 4∶(3-4)∶(2-3).

[0007] The present invention ingeniously combines solid-solid phase change (PUPCM) with solid-liquid phase change, prepares a polyurethane phase change material into a microsphere wall and coats an anti-cold ice suppressant and an asphalt rejuvenator. In addition, by embedding an electromagnetic induction material, carbon nanotubes, into the self-healing core wall, a double-layer protection mechanism with ice resistance, temperature reduction, and self-healing functions is comprehensively formed, which can realize the self-temperature regulation mechanism of the road surface through phase change heat absorption and heat release under severe cold and hot weather conditions, and avoid the problem of road surface cracking caused by temperature stress. When the road cracks under harsh environments, the microspheres can rupture in time and release the rejuvenator to repair the cracks. At the same time, it can be used as a material for functional road surface paving and road surface preventive maintenance.

[0008] Furthermore, the specific preparation steps of the self-healing core microsphere include:

[0009] Mix phenol, formaldehyde solution, deionized water, and carbon nanotubes, disperse them by ultrasonic wave and stir, adjust the pH to 8-10, and perform the first water bath stirring to obtain a magnetic thermal cracking release ball wall prepolymer;

[0010] Dissolve sodium dodecylbenzenesulfonate in water, add an asphalt rejuvenator, adjust the pH to 7-8, and perform the second water bath stirring to obtain a rejuvenator emulsion core material;

[0011] Add the rejuvenator emulsion core material to the magnetic thermal cracking release ball wall prepolymer, adjust the pH to 7-9, perform the third water bath stirring, cool, wash, and dry to obtain a self-healing core microsphere.

[0012] Even further, the concentration of the formaldehyde solution is 37 wt%; and / or

[0013] The carbon nanotubes are single-walled carbon nanotubes; and / or

[0014] The mass ratio of phenol to formaldehyde solution is (3-4)∶(5-6); and / or

[0015] The dosage of the carbon nanotubes is 10% of the sum of the masses of phenol and formaldehyde solution; and / or

[0016] The asphalt rejuvenator is sunflower oil, and the addition amount is 65% of the sum of the masses of phenol and formaldehyde solution; and / or

[0017] The conditions for the first water bath stirring are: stirring at 70°C and 400 - 600 rpm for 90 min; and / or

[0018] The conditions for the second water bath stirring are: stirring at 40°C and 400 - 600 rpm for 10 - 30 min; and / or

[0019] The conditions for the third water bath stirring are: stirring at 70°C and 500 - 700 rpm for 2 - 3 h.

[0020] Furthermore, the specific preparation steps of the urethane thermal regulation outer shell spherical wall prepolymer include: subjecting the soft segment material and the hard segment material to vacuum filtration, then dissolving them in a medium solvent, adding a catalyst, heating and reacting under nitrogen protection, adding a hardener, and continuing to heat and react to obtain the urethane thermal regulation outer shell spherical wall prepolymer.

[0021] Even further, the mass ratio of the soft segment material, the hard segment material, and the hardener is (1 - 3)∶(4 - 6)∶1; and / or

[0022] The soft segment material is polyethylene glycol 2000; and / or

[0023] The hard segment material is hexamethylene diisocyanate (HDI); and / or

[0024] The medium solvent is dimethylformamide (DMF); and / or

[0025] The catalyst is dibutyltin; and / or

[0026] The hardener is melamine; and / or

[0027] The conditions for the vacuum filtration are: filtering under vacuum conditions at 100 - 120°C for 2 - 3 h; and / or

[0028] The conditions for the heating are: reacting at 50 - 70°C for 3 - 4 h; and / or

[0029] The conditions for the continued heating are: reacting at 60 - 80°C for 4 - 6 h.

[0030] Furthermore, the specific preparation steps of the cold resistance and ice inhibition agent include: mixing polyethylene glycols with a saline compound and stirring evenly to obtain the cold resistance and ice inhibition agent.

[0031] Even further, the mass ratio of the polyethylene glycols to the saline compound is (4 - 9)∶1; and / or

[0032] The molecular weight of the polyethylene glycols is one or more of 200, 400, and 600; and / or

[0033] The saline compound is calcium chloride hydrate (CaCl2·6H2O).

[0034] The second object of the present invention is to provide a preparation method of phase change ice inhibition and self-healing double-layer microspheres, comprising the following steps:

[0035] Immerse the self-healing core microspheres into the cold-resistant ice inhibitor, add a cross-linking agent and a stabilizer for coating to uniformly coat a coating layer on the surface thereof, cool and dry to obtain ice inhibition micro-nuclei;

[0036] Immerse the ice inhibition micro-nuclei into the polyurethane heat regulation outer shell wall prepolymer solution, stir and disperse ultrasonically, and then carry out a cross-linking curing reaction to form a stable coating layer to obtain phase change ice inhibition and self-healing double-layer microspheres.

[0037] The present invention adopts a step-by-step coating process to precisely control the thickness of each layer of material to ensure the full play of the phase change function, while maintaining the stability of the shape and structure of the microspheres, effectively avoiding the occurrence of rupture and adhesion phenomena.

[0038] Further, the cross-linking agent is glutaraldehyde; and / or

[0039] The stabilizer is polyvinyl alcohol; and / or

[0040] The mass ratio of the cross-linking agent, the stabilizer and the cold-resistant ice inhibitor is 1∶1∶(50-60); and / or

[0041] The thickness ratio of the polyurethane heat regulation outer shell wall prepolymer, the cold-resistant ice inhibitor and the self-healing core microspheres is 4∶(3-4)∶(2-3), and this ratio can ensure the best balance of the functions and structural stability of each component.

[0042] The third object of the present invention is to provide an application of the phase change ice inhibition and self-healing double-layer microspheres in normal temperature asphalt.

[0043] The phase change ice inhibition and self-healing double-layer microspheres of the present invention can be widely applied to construction operations such as spraying and mixing in emulsified asphalt, and are suitable for various construction processes such as functional wearing courses and fog seal layers. In addition, the present invention can also be added to cold mix asphalt mixtures for paving or added to functional asphalt coatings that must have functions such as ice inhibition and heat insulation, providing multiple protection functions for roads and enhancing the durability and adaptability of road surfaces.

[0044] The present invention constructs a multifunctional microsphere by preparing a polyurethane solid-solid phase change material into a heat-regulating outer shell with a spherical wall wrapping a phase change ice suppression solution and an electromagnetic release self-healing core microsphere with carbon nanotubes embedded in the microsphere wall, which has an ice suppression, temperature reduction and self-healing mechanism. Its mechanism of action is as follows: on the one hand, when the external environmental temperature rises, the heat-regulating outer shell will undergo a solid-solid phase change, absorbing external heat without leaking the phase change ice suppression solution, thereby achieving a temperature control effect, and at the same time avoiding the rupture of the self-healing core microsphere due to excessive temperature inside the microsphere and the premature release of the asphalt rejuvenator; when the external temperature drops, the phase change ice suppression solution in the middle layer will undergo a solid-liquid phase change, thereby reducing the surface temperature of the microsphere and inhibiting the freezing of water, enabling the microsphere to effectively inhibit the formation of ice and frost in extreme weather; the combination of the two can ensure that the microsphere has an effective temperature control effect in different temperature ranges and resist the pavement cracking problem caused by excessive temperature stress; on the other hand, when the temperature control effect of the phase change material weakens under extreme weather conditions and the pavement cracks, the embedded carbon nanotubes can be stimulated by electromagnetic waves at that time, generating a thermal effect through local heating, causing the asphalt rejuvenator to "explode" out, and then repairing the cracks to ensure that the pavement function is repaired in time.

[0045] Compared with the prior art, the present invention has the following advantages and technical effects:

[0046] The present invention provides a double-layer microsphere structure, which organically combines the functions of ice suppression, temperature control and self-healing, breaks through the limitations of the single function of traditional technologies, and realizes comprehensive responses under multiple levels and multiple environmental conditions. This innovative design enhances the performance of the microsphere in terms of temperature regulation, self-healing and environmental adaptability.

[0047] The present invention adopts a polyurethane solid-solid phase change heat-regulating outer shell. When the temperature is high, the outer shell melts and absorbs heat, reducing the heat damage to the pavement; when it solidifies, it releases heat to balance the surrounding temperature. Combined with the solid-liquid phase change ice suppression solution, the microsphere can effectively cool down and suppress ice in a wide temperature range from -15°C to 55°C. By introducing a phase change function into the polyurethane capsule wall and avoiding liquid leakage, the integrity and stability of the microsphere structure are ensured.

[0048] In addition, by embedding carbon nanotubes in the self-healing core microsphere wall and activating them by electromagnetic stimulation, the "exploding bead" effect is achieved. This design realizes remote precise control and rapid release of the core material for local repair, phase change ice suppression and temperature reduction operations, while enhancing the strength and anti-leakage performance of the sphere wall.

[0049] The materials of the present invention are environmentally friendly. The release of the rejuvenator repairs pavement cracks and extends the life of asphalt, reducing maintenance costs and resource waste, and having both economic benefits and environmental value. Description of the Drawings

[0050] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0051] Figure 1 is a schematic structural diagram of the phase change ice suppression and self - repair double - layer microspheres prepared in the embodiments of the present invention;

[0052] Figure 2 is the cooling curve of the samples prepared in Examples 1 - 2, Comparative Examples 1 - 3 and the matrix asphalt;

[0053] Figure 3 is the heating curve of the samples prepared in Examples 1 - 2, Comparative Examples 1 - 3 and the matrix asphalt. Detailed Description of the Invention

[0054] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation to the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0055] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0056] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0057] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are only exemplary.

[0058] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open - ended terms, that is, they are intended to include but not limited to.

[0059] The specific technical solution is as follows:

[0060] A preparation method of a phase change ice suppression and self-healing double-layer microsphere, comprising the following steps:

[0061] (1) Preparation of self-healing core microspheres:

[0062] Mix phenol, formaldehyde solution, deionized water and carbon nanotubes, ultrasonically disperse and stir, adjust the pH to 8-10, and perform the first water bath stirring to obtain a magnetic thermal cracking and releasing spherical wall prepolymer;

[0063] Dissolve sodium dodecylbenzenesulfonate in water, add an asphalt rejuvenator, adjust the pH to 7-8, and perform the second water bath stirring to obtain a rejuvenator emulsion core material;

[0064] Add the rejuvenator emulsion core material to the magnetic thermal cracking and releasing spherical wall prepolymer, adjust the pH to 7-9, perform the third water bath stirring, cool, wash, and dry to obtain self-healing core microspheres;

[0065] (2) Preparation of a polyurethane thermal regulation outer shell spherical wall prepolymer:

[0066] Perform vacuum filtration on the soft segment material and the hard segment material, then dissolve them in a medium solvent, add a catalyst, heat and react under nitrogen protection, then add a hardener, and continue to heat and react to obtain a polyurethane thermal regulation outer shell spherical wall prepolymer;

[0067] (3) Preparation of an anti-freezing and ice-suppressing agent:

[0068] Mix polyethylene glycols and saline compounds and stir evenly to obtain an anti-freezing and ice-suppressing agent;

[0069] (4) Immerse the self-healing core microspheres in the anti-freezing and ice-suppressing agent, add a cross-linking agent and a stabilizer for coating, so that a uniform layer is coated on the surface, cool and dry to obtain ice suppression micro-nuclei;

[0070] Immerse the ice suppression micro-nuclei in the polyurethane thermal regulation outer shell spherical wall prepolymer solution, stir and ultrasonically disperse, and then perform a cross-linking and curing reaction to form a stable coating layer to obtain a phase change ice suppression and self-healing double-layer microsphere.

[0071] In the following examples of the present invention, in step (1):

[0072] The concentration of the formaldehyde solution is 37 wt%;

[0073] The carbon nanotubes are single-walled carbon nanotubes;

[0074] The mass ratio of the phenol to the formaldehyde solution is (3-4):(5-6); for example, in the following preferred examples of the present invention, the mass ratio of the phenol to the formaldehyde solution can be selected as 1:1.5;

[0075] The amount of the carbon nanotubes used is 10% of the sum of the mass of the phenol and formaldehyde solutions;

[0076] The conditions for the first water bath stirring are: stirring at 70°C and 400-600 rpm for 90 min; the speed can be kept within this range, and adjustment within the range will not affect the product performance, so the speed can be arbitrarily limited within the range value in the following embodiments of the present invention;

[0077] The conditions for the second water bath stirring are: stirring at 40°C and 400-600 rpm for 10-30 min; the speed can be kept within this range, and adjustment within the range will not affect the product performance, so the speed can be arbitrarily limited within the range value in the following embodiments of the present invention;

[0078] The conditions for the third water bath stirring are: stirring at 70°C and 500-700 rpm for 2-3 hours, and the rotation speed can be kept within this range. Adjustment within the range will not affect product performance. Therefore, in the following embodiments of the present invention, the rotation speed can be arbitrarily limited within the range value.

[0079] In the following embodiments of the present invention, in step (2):

[0080] The mass ratio of the soft segment material, the hard segment material and the hardener is (1-3): (4-6): 1; illustratively, in the following preferred embodiments of the present invention, the mass ratio of the soft segment material, the hard segment material and the hardener can be selected as 2:5:1 or 3:4:1;

[0081] The soft segment material is polyethylene glycol 2000;

[0082] The hard segment material is hexamethylene diisocyanate (HDI);

[0083] The medium solvent is dimethylformamide (DMF);

[0084] The catalyst is dibutyltin;

[0085] The hardener is melamine;

[0086] The vacuum filtration conditions are: filtration at 100-120°C for 2-3h, and the specific filtration temperature and time are based on the removal of residual moisture in the material;

[0087] The heating condition is: reacting at 50-70°C for 3-4h; illustratively, in the following preferred embodiments of the present invention, the heating can be selected to react at 70°C for 3h;

[0088] The conditions for the subsequent heating are: reacting at 60 - 80°C for 4 - 6 h. Exemplarily, in the following preferred embodiments of the present invention, the heating can be selected to react at 80°C for 4 h.

[0089] In some embodiments of the present invention, in step (3):

[0090] The mass ratio of the polyethylene glycols to the saline compound is (4 - 9)∶1. Exemplarily, in the following preferred embodiments of the present invention, the mass ratio of the polyethylene glycols to the saline compound can be selected as 4∶1 or 9∶1;

[0091] The molecular weight of the polyethylene glycols is one or more of 200, 400, and 600; Exemplarily, in the following preferred embodiments of the present invention, the molecular weight of the polyethylene glycols can be selected as 200;

[0092] The saline compound is calcium chloride hydrate (CaCl₂·6H₂O).

[0093] In the following embodiments of the present invention, in step (4):

[0094] The crosslinking agent is glutaraldehyde;

[0095] The stabilizer is polyvinyl alcohol;

[0096] The mass ratio of the crosslinking agent, the stabilizer, and the anti - cold and ice - inhibiting agent is 1∶1∶(50 - 60); Exemplarily, in the following preferred embodiments of the present invention, the mass ratio of the crosslinking agent, the stabilizer, and the anti - cold and ice - inhibiting agent can be selected as 1∶1∶50;

[0097] In the obtained double - layer microspheres, the thickness ratio of the urethane thermal - regulation outer - shell spherical - wall prepolymer, the anti - cold and ice - inhibiting agent, and the self - healing core microspheres is 4∶(3 - 4)∶(2 - 3). Exemplarily, in the following preferred embodiments of the present invention, the thickness ratio of the urethane thermal - regulation outer - shell spherical - wall prepolymer, the anti - cold and ice - inhibiting agent, and the self - healing core microspheres is 4∶3∶3.

[0098] In the present invention, the "normal temperature" refers to 20 - 30°C unless otherwise specified.

[0099] The raw materials used in the present invention are all obtained by purchasing on the market.

[0100] The technical solutions of the present invention are further described below through examples.

[0101] Example 1

[0102] A preparation method of phase - change ice - inhibiting and self - repairing double - layer microspheres, comprising the following steps:

[0103] (1) Preparation of self - healing core microspheres:

[0104] Add 5 g of phenol and 7.5 g of 37 wt% formaldehyde solution to a round-bottom flask, stir, then add 50 mL of deionized water and stir evenly. Then add 10% of single-walled carbon nanotubes based on the sum of the masses of phenol and 37 wt% formaldehyde solution, ultrasonically disperse for 0.5 h, adjust the pH to 8 using 5 wt% sodium hydroxide solution, and stir at a constant speed of 400 r / min in a 70 °C water bath for 90 min to obtain the magnetic thermal cracking release sphere wall prepolymer;

[0105] Dissolve 7.5 g of sodium dodecylbenzenesulfonate in 100 mL of water, add 8.125 g of asphalt rejuvenator (sunflower oil), adjust the pH to 8, and stir at 400 rpm in a 40 °C water bath for 30 min to obtain the rejuvenator emulsion core material;

[0106] Add the rejuvenator emulsion core material to the magnetic thermal cracking release sphere wall prepolymer, adjust the pH to 9, stir at a constant speed of 500 r / min in a 70 °C water bath for 2 h, cool to room temperature, wash, and dry to obtain the self-healing core microspheres;

[0107] (2) Preparation of the polyurethane thermal regulation outer shell sphere wall prepolymer outer shell solution:

[0108] Filter 5 g of polyethylene glycol 2000 and 12.5 g of hexamethylene diisocyanate (HDI) under vacuum at 120 °C for 2 h to remove residual moisture in the material. Then dissolve the treated polyethylene glycol 2000 and hexamethylene diisocyanate in N,N-dimethylformamide (DMF), add 1 g of dibutyltin, react at 70 °C for 3 h under nitrogen protection, and then add 2.5 g of melamine and react at 80 °C for 4 h to obtain the polyurethane thermal regulation outer shell sphere wall prepolymer; among them, the mass ratio of polyethylene glycol 2000, hexamethylene diisocyanate, and melamine is 2:5:1;

[0109] (3) Preparation of the anti-freezing and ice-suppressing agent:

[0110] Dissolve 5 g of polyethylene glycol 200 in 100 mL of deionized water, stir evenly at 50 °C and 300 rpm until completely dissolved. After cooling to room temperature, add 1.25 g of calcium chloride hydrate (CaCl2·6H2O). The mass ratio of polyethylene glycol 200 to calcium chloride hydrate (CaCl2·6H2O) is 4:1, and continue to stir until there is no particle precipitation to obtain the anti-freezing and ice-suppressing agent;

[0111] (4) Immerse the dried self-healing core microspheres in the anti-freezing and ice-suppressing agent, stir at 200 rpm for 30 min to evenly cover the surface of the anti-freezing and ice-suppressing agent, then add glutaraldehyde and polyvinyl alcohol, and react at 45 °C and then stably coat to obtain the ice-suppressing micro-nuclei; among them, the mass ratio of glutaraldehyde, polyvinyl alcohol, and the anti-freezing and ice-suppressing agent is 1:1:50;

[0112] (5) Immerse the ice - inhibiting micro - nuclei into the prepolymer solution of the urethane heat - regulating outer - shell spherical wall. The thickness ratio of the urethane heat - regulating outer - shell spherical wall prepolymer, the cold - resistant ice - inhibiting agent, and the self - healing core micro - spheres is 4:3:3. Stir and disperse ultrasonically, and then carry out the cross - linking and curing reaction (i.e., stirring) to form a stable coating layer, obtaining the phase - change ice - inhibiting and self - repairing double - layer micro - spheres.

[0113] Example 2

[0114] A preparation method of phase - change ice - inhibiting and self - repairing double - layer micro - spheres, comprising the following steps:

[0115] (1) The preparation of the self - healing core micro - spheres is the same as that in Example 1:

[0116] (2) Preparation of the urethane heat - regulating outer - shell spherical wall prepolymer:

[0117] Filter 6 g of polyethylene glycol 2000 and 8 g of hexamethylene diisocyanate (HDI) under vacuum at 120 °C for 2 h to remove residual moisture in the materials. Then dissolve the treated polyethylene glycol 2000 and hexamethylene diisocyanate in dimethylformamide (DMF), add 1 g of dibutyltin, react at 70 °C for 3 h under nitrogen protection, and then add 2 g of melamine and react at 80 °C for 4 h to obtain the urethane heat - regulating outer - shell spherical wall prepolymer; wherein, the mass ratio of polyethylene glycol 2000, hexamethylene diisocyanate, and melamine is 3:4:1;

[0118] (3) Preparation of the cold - resistant ice - inhibiting agent:

[0119] Dissolve 9 g of polyethylene glycol 200 in 100 mL of deionized water, stir evenly at 50 °C and 300 rpm until completely dissolved, cool to room temperature, and then add 1 g of calcium chloride hydrate (CaCl2·6H2O). The mass ratio of polyethylene glycol 200 to calcium chloride hydrate (CaCl2·6H2O) is 9:1, and continue to stir until there is no particle precipitation to obtain the cold - resistant ice - inhibiting agent;

[0120] (4) Immerse the dried self - healing core micro - spheres into the cold - resistant ice - inhibiting agent, stir at 200 rpm for 30 min to make its surface evenly covered with the cold - resistant ice - inhibiting agent, then add glutaraldehyde and polyvinyl alcohol, and react at 45 °C to obtain a stable coating to get the ice - inhibiting micro - nuclei; wherein, the mass ratio of glutaraldehyde, polyvinyl alcohol, and the cold - resistant ice - inhibiting agent is 1:1:50;

[0121] (5) Immerse the ice - inhibiting micro - nuclei into the prepolymer solution of the urethane heat - regulating outer - shell spherical wall. The thickness ratio of the urethane heat - regulating outer - shell spherical wall prepolymer, the cold - resistant ice - inhibiting agent, and the self - healing core micro - spheres is 4:3:3. Stir and disperse ultrasonically, and then carry out the cross - linking and curing reaction (i.e., stirring) to form a stable coating layer, obtaining the phase - change ice - inhibiting and self - repairing double - layer micro - spheres.

[0122] Figure 1Schematic diagram of the structure of the phase change ice inhibition and self - healing double - layer microspheres prepared in the embodiments of the present invention.

[0123] Comparative Example 1

[0124] Same as Example 1, except that the urethane thermal - regulation outer - shell pre - polymer outer shell is not introduced. The specific method is as follows:

[0125] (1) The preparation of the self - healing core microspheres is the same as that in Example 1:

[0126] (2) Preparation of the cold - resistant ice inhibitor:

[0127] Dissolve 5 g of polyethylene glycol 200 in 100 mL of deionized water, stir evenly at 50 °C and 300 rpm until completely dissolved, cool to room temperature, and then add 1.25 g of calcium chloride hydrate (CaCl2·6H2O). The mass ratio of polyethylene glycol 200 to calcium chloride hydrate (CaCl2·6H2O) is 4:1. Continue to stir until there is no particle precipitation to obtain the cold - resistant ice inhibitor;

[0128] (3) Immerse the dried self - healing core microspheres in the cold - resistant ice inhibitor, stir at 200 rpm for 30 min to uniformly cover the surface of the microspheres with the cold - resistant ice inhibitor, then add glutaraldehyde and polyvinyl alcohol, and react at 45 °C and then stably coat to obtain the ice - inhibition micro - nuclei; among them, the mass ratio of glutaraldehyde, polyvinyl alcohol, and the cold - resistant ice inhibitor is 1:1:50.

[0129] Comparative Example 2

[0130] Same as Example 1, except that the ice - inhibition micro - nuclei are not introduced, that is: the specific method is as follows:

[0131] Preparation of the urethane thermal - regulation outer - shell pre - polymer outer shell:

[0132] Filter 5 g of polyethylene glycol 2000 and 12.5 g of hexamethylene diisocyanate (HDI) under vacuum at 120 °C for 2 h to remove residual moisture in the material. Then dissolve the treated polyethylene glycol 2000 and hexamethylene diisocyanate in dimethylformamide (DMF), add 1 g of dibutyltin, react at 70 °C for 3 h under nitrogen protection, and then add 2.5 g of melamine and react at 80 °C for 4 h to obtain the urethane thermal - regulation outer - shell pre - polymer; among them, the mass ratio of polyethylene glycol 2000, hexamethylene diisocyanate, and melamine is 2:5:1; then carry out a cross - linking and curing reaction (i.e., stirring) to obtain the urethane thermal - regulation outer - shell pre - polymer outer - shell material.

[0133] Comparative Example 3

[0134] Same as Example 1, except that the self - healing core microspheres are not introduced. The specific method is as follows:

[0135] (1) Preparation of the urethane heat-regulating outer shell spherical wall prepolymer shell:

[0136] Filter 5 g of polyethylene glycol 2000 and 12.5 g of hexamethylene diisocyanate (HDI) under vacuum at 120 °C for 2 h to remove residual moisture in the material. Then dissolve the treated polyethylene glycol 2000 and hexamethylene diisocyanate in dimethylformamide (DMF), add 1 g of dibutyltin, and react at 70 °C for 3 h under nitrogen protection. Then add 2.5 g of melamine and react at 80 °C for 4 h to obtain the urethane heat-regulating outer shell spherical wall prepolymer; among them, the mass ratio of polyethylene glycol 2000, hexamethylene diisocyanate, and melamine is 2∶5∶1;

[0137] (2) Preparation of the cold-resistant and ice-inhibiting agent:

[0138] Dissolve 5 g of polyethylene glycol 200 in 100 mL of deionized water, stir evenly at 50 °C and 300 rpm until completely dissolved, cool to room temperature, and then add 1.25 g of calcium chloride hydrate (CaCl2·6H2O). The mass ratio of polyethylene glycol 200 to calcium chloride hydrate (CaCl2·6H2O) is 4∶1, and continue to stir until there is no particle precipitation to obtain the cold-resistant and ice-inhibiting agent;

[0139] (3) Add glutaraldehyde and polyvinyl alcohol to the cold-resistant and ice-inhibiting agent, and react at 45 °C to obtain the cold-resistant and ice-inhibiting agent spheres; among them, the mass ratio of glutaraldehyde, polyvinyl alcohol, and the cold-resistant and ice-inhibiting agent is 1∶1∶50;

[0140] (4) Immerse the cold-resistant and ice-inhibiting agent spheres in the solution of the urethane heat-regulating outer shell spherical wall prepolymer. The thickness ratio of the urethane heat-regulating outer shell spherical wall prepolymer, the cold-resistant and ice-inhibiting agent, and the self-healing core microspheres is 4∶3∶3. Stir and ultrasonically disperse, and then carry out a cross-linking and curing reaction (i.e., stirring) to form microspheres.

[0141] Performance test:

[0142] (1) Temperature regulation performance test: Incorporate the samples prepared in Examples 1-2 and Comparative Examples 1-3 into matrix asphalt (BA) at a dosage of 60% to prepare modified asphalt. Place the matrix asphalt and the modified asphalt at room temperature for 3 hours, then put them into a freezer together and cool to -14 °C. After removal, quickly put them into an oven and heat up from 18 °C to 65 °C. During this process, use a multi-channel temperature tester UT3216 to monitor the temperature curve. The test results are shown in Figure 2 and Figure 3 .

[0143] From Figure 2 and 3It can be seen that in the temperature range of -15°C to 55°C, the temperature of Examples 1-2 of the present invention can be autonomously adjusted. At the same time, the temperature rise can be delayed by about 12°C at most during the heating process; the temperature drop can be delayed by about 5°C at most during the cooling process. Comparative Example 1 lacks a thermal regulation shell and only contains ice-inhibiting micro-nuclei. Combining with the temperature regulation curve, it is obvious that its temperature drop delay effect is obvious during cooling, and there is almost no temperature rise delay effect during heating; Comparative Example 2 only contains a polyurethane thermal regulation shell. From the images, it can be seen that its temperature rise delay effect is better while the temperature drop delay effect is not obvious; Comparative Example 3 has the dual effects of a thermal regulation shell and an anti-freezing and ice-inhibiting agent, and does not contain self-healing core microspheres. It can be found from the images that its temperature regulation effect is relatively close to that of Example 1 and Example 2, but the temperature rise delay effect is poor. Obviously, Comparative Examples 1-3 have disadvantages for both low-temperature applications and high-temperature applications. At the same time, the combination of the polyurethane thermal regulation shell, the ice-inhibiting agent and the self-healing core microspheres has successfully brought better phase change heat storage capacity and stable temperature regulation effect, making Examples 1-2 have better functionality and applicability in practical applications.

[0144] (2) Microsphere response temperature test: Using an electromagnetic heating device, the output voltage is set to 600V, the coil height (the distance between the induction coil and the heating sample) is set to 1.5 cm, and the magnetic field frequency of the electromagnetic heater is 124 kHz. The heating interval is 200 s. Use a thermal infrared camera to collect the temperature response of Example 1 and Comparative Example 1 at different time points. The test results of the experiment are shown in Table 1.

[0145] Table 1 Electromagnetic experiment parameters

[0146]

[0147] As can be seen from Table 2, under the stimulation of electromagnetic waves, as the temperature rises, the asphalt rejuvenator can be gradually released. At the same time, the response temperature of Example 1 is higher than that of Comparative Example 1 (without introducing the urethane thermal regulation shell and the prepolymer shell of the microsphere wall), indicating that the double-layer design of the microsphere shows strong heat resistance in a high-temperature environment and can achieve effective release. The heat conduction performance and magnetic induction performance of carbon nanotubes play a crucial role in this process, which also shows the ingenious cooperation between the microsphere structure and the functional materials under extreme conditions.

[0148] The above is only the preferred specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A phase change ice suppression and self - healing double - layer microsphere, characterized in that The phase change ice suppression and self - healing double - layer microspheres use a urethane thermal - regulation outer - shell wall prepolymer as the outer shell, a self - healing core microsphere as the inner core, and an anti - cold ice - suppression agent is sandwiched between the outer shell and the inner core to form a double - layer microsphere structure.

2. The phase change ice suppression and self-healing double-layer microspheres according to claim 1, wherein The specific preparation steps of the self - healing core microspheres include: Mix phenol, formaldehyde solution, deionized water, and carbon nanotubes, disperse them by ultrasonic wave and stir, adjust the pH to 8 - 10, and perform the first water - bath stirring to obtain a magnetothermal cracking release wall prepolymer. Dissolve sodium dodecylbenzenesulfonate in water, add an asphalt rejuvenator, adjust the pH to 7 - 8, and perform the second water - bath stirring to obtain a rejuvenator emulsion core material. Add the rejuvenator emulsion core material to the magnetothermal cracking release wall prepolymer, adjust the pH to 7 - 9, perform the third water - bath stirring, cool, wash, and dry to obtain self - healing core microspheres.

3. The phase change ice suppression and self - healing double - layer microspheres according to claim 2, wherein the concentration of the formaldehyde solution is 37 wt%; and / or the carbon nanotubes are single - wall carbon nanotubes; and / or the mass ratio of phenol to formaldehyde solution is (3 - 4):(5 - 6); and / or the dosage of the carbon nanotubes is 10% of the sum of the masses of phenol and formaldehyde solution; and / or the asphalt rejuvenator is sunflower seed oil, and the addition amount is 65% of the sum of the masses of phenol and formaldehyde solution; and / or the conditions of the first water - bath stirring are: stirring at 70 °C and 400 - 600 rpm for 90 min; and / or the conditions of the second water - bath stirring are: stirring at 40 °C and 400 - 600 rpm for 10 - 30 min; and / or the conditions of the third water - bath stirring are: stirring at 70 °C and 500 - 700 rpm for 2 - 3 h.

4. The phase change ice suppression and self-healing double-layer microspheres according to claim 1, characterized in that, The specific preparation steps of the urethane thermal - regulation outer - shell wall prepolymer include: subjecting the soft - segment material and the hard - segment material to vacuum filtration, then dissolving them in a medium solvent, adding a catalyst, heating and reacting under nitrogen protection, adding a hardening agent, and continuing to heat and react to obtain a urethane thermal - regulation outer - shell wall prepolymer.

5. The phase change ice suppression and self - healing double - layer microspheres according to claim 4, wherein the mass ratio of the soft - segment material, the hard - segment material, and the hardening agent is (1 - 3):(4 - 6):1; and / or the soft - segment material is polyethylene glycol 2000; and / or the hard - segment material is hexamethylene diisocyanate; and / or the medium solvent is formamide dimethylamine; and / or the catalyst is dibutyltin; and / or the hardening agent is melamine; and / or the conditions of the vacuum filtration are: filtering under vacuum at 100 - 120 °C for 2 - 3 h; and / or the conditions of the heating are: reacting at 50 - 70 °C for 3 - 4 h; and / or the conditions of the continuing heating are: reacting at 60 - 80 °C for 4 - 6 h.

6. The phase change ice suppression and self-healing double-layer microspheres according to claim 1, wherein The specific preparation steps of the anti - cold ice - suppression agent include: mixing polyethylene glycols and salt hydrates and stirring evenly to obtain an anti - cold ice - suppression agent.

7. The phase change ice suppression and self - healing double - layer microspheres according to claim 6, wherein the mass ratio of polyethylene glycols to salt hydrates is (4 - 9):1; and / or The molecular weight of the polyethylene glycol is one or more of 200, 400, and 600; and / or The saline compound is calcium chloride hydrate.

8. A method for preparing the phase change ice suppression and self-repairing double-layer microspheres according to any one of claims 1-7, characterized in that, Comprising the following steps: Immerse the self-healing core microspheres in the anti-freezing and ice-suppressing agent, add a cross-linking agent and a stabilizer for coating, so that a uniform coating layer is coated on the surface, cool and dry to obtain ice-suppressing micro-nuclei; Immerse the ice-suppressing micro-nuclei in a polyurethane thermal regulation outer shell wall prepolymer solution, stir and ultrasonically disperse, and then carry out a cross-linking and curing reaction to form a stable coating layer to obtain a phase change ice-suppressing and self-healing double-layer microsphere.

9. The method for preparing a phase change ice-suppressing and self-healing double-layer microsphere according to claim 8, wherein The cross-linking agent is glutaraldehyde; and / or The stabilizer is polyvinyl alcohol; and / or The mass ratio of the cross-linking agent, the stabilizer, and the anti-freezing and ice-suppressing agent is 1∶1∶(50-60).

10. An application of the phase change ice-suppressing and self-healing double-layer microsphere according to any one of claims 1-7 in normal temperature asphalt.

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