A self-healing encapsulation material and its preparation method

Abstract

This invention relates to the field of epoxy resin self-healing materials, specifically a self-healing encapsulation material and its preparation method. This invention solves the problem of the mutual exclusion between high crosslinking density and high repair efficiency in traditional self-healing materials. The self-healing encapsulation material is prepared by mixing bisphenol A type epoxy resin, terminal epoxy-terminated hyperbranched polysiloxane, aminated mesoporous silica loaded with bisphenol F resin, and a dual-dynamic bond curing agent containing imine and disulfide bonds, followed by stepwise curing. This invention achieves deep synergy between intrinsic network exchange of dual-dynamic covalent bonds and the release of exogenous repair agents from microcapsules, and utilizes hyperbranched siloxane to impart extremely high slippage to the chain segments, effectively accelerating the physical entanglement and chemical healing of the crack interface. Simultaneously, the aminated inorganic framework ensures the mechanical strength of the system through covalent anchoring. The resulting material possesses both high mechanical strength and excellent multi-microcrack self-healing capability.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin self-healing materials technology, specifically to a self-healing encapsulation material and its preparation method. Background Technology

[0002] Epoxy resin, as a high-performance thermosetting polymer, is widely used in the preparation of encapsulation materials due to its excellent mechanical properties, heat resistance, dimensional stability, and good adhesion. However, during long-term service, under the influence of alternating hot and cold environments or external stress, microcracks are easily generated inside cured epoxy resin. These microscopic defects are often deeply hidden inside the material and are difficult to detect and repair in time. With the continuous accumulation of stress, the microcracks will continue to expand and penetrate, eventually providing a channel for the penetration of external moisture, oxygen, and corrosive media, leading to physical damage or performance degradation of the encapsulated precision internal components and causing irreversible failure of the entire system.

[0003] To extend the service life and improve the reliability of materials, endowing epoxy resin with self-healing capabilities has become a key research direction in the field of polymer materials. Currently, existing technologies face a core inherent contradiction in practical applications: the mutual exclusion between high crosslinking density and high repair efficiency. Specifically, to ensure that the encapsulation material possesses sufficiently high mechanical strength, barrier properties, and heat resistance, a high crosslinking density of the polymer network must be maintained; however, this greatly restricts the mobility of polymer molecular chains, resulting in an extremely slow internal dynamic covalent bond exchange rate, or making it difficult for the added liquid repair agent to diffuse within the dense network, thus leading to low repair efficiency. Conversely, if the crosslinking density is reduced or a large number of flexible segments are introduced to increase the chain migration rate, the intrinsic mechanical strength and protective barrier properties of the encapsulation material will inevitably be severely weakened. How to break through this physical barrier between "high rigidity and highly active molecular movement," and achieve efficient self-healing of microcracks without sacrificing the macroscopic protective performance of the encapsulation material, is a bottleneck problem that urgently needs to be solved in this field.

[0004] To address this, a self-healing encapsulation material and its preparation method are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a self-healing encapsulation material and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: Unless otherwise specified, all parts in this invention are parts by weight.

[0007] This invention provides a method for preparing a self-healing encapsulation material, the method being as follows: 100 parts of bisphenol A type epoxy resin E51 are taken and heated to 60°C; 5-10 parts of terminal epoxy group hyperbranched polysiloxane and 8-15 parts of supported mesoporous silica are added; the mixture is stirred and dispersed for 30-60 minutes at 2500 rpm and 60°C using a high-shear emulsifying disperser to obtain a mixture; the mixture is cooled to 40°C, and according to the molar ratio of total epoxy groups to active hydrogen in the dual dynamic bond curing agent being 1:1, the corresponding dual dynamic bond curing agent is added, and the mixture is mixed at 300 rpm for 15 minutes, followed by vacuum degassing for 10 minutes to obtain a degassed epoxy resin system; the degassed epoxy resin system is subjected to stepwise curing, and after natural cooling to room temperature, it is demolded to obtain the self-healing encapsulation material. Supported mesoporous silica is prepared from mesoporous silica, 3-aminopropyltriethoxysilane and bisphenol F type epoxy resin; The dual dynamic bond curing agent is prepared from 4,4'-diaminodiphenyl disulfide and terephthalaldehyde.

[0008] The preferred method for preparing terminal epoxy-terminated hyperbranched polysiloxanes is as follows: Under nitrogen protection, 32.87 parts of tetra(dimethylsiloxy)silane and 130 parts of anhydrous toluene are added to a three-necked flask, and mechanical stirring is started at a speed of 400 rpm; 0.013 parts of Karstedt catalyst (a xylene solution with a platinum mass fraction of 2000 ppm) are added using a microsyringe, and the temperature is raised to 60°C; 12.63 parts of methyldiallylsilane are dissolved in 50 parts of anhydrous toluene, and added dropwise to the three-necked flask at a rate of 1.5 mL / min through a constant pressure dropping funnel. After the addition is complete, the reaction is maintained at 60°C for 4 hours (at this temperature, the Si-H in the monomer preferentially adds to the allyl group of the other monomer, rapidly diverging outward to form a hydroxyl-free hyperbranched siloxane framework, and the edges are preserved). (Leaving a large number of unreacted Si-H active sites); heat to 85℃, increase the stirring speed to 600 rpm, mix 22-32 parts of allyl glycidyl ether with 30 parts of anhydrous toluene, and add the mixture dropwise into the reaction system at a uniform rate over 30 min, then react for 5-8 h; allow the system to cool naturally to room temperature, add 5 parts of activated carbon, and stir at 300 rpm for 30 min to adsorb and complex the residual platinum catalyst in the system, then vacuum filter through a polytetrafluoroethylene filter membrane with a pore size of 0.22 μm; transfer the filtrate to a rotary evaporator, and remove the toluene solvent and unreacted excess allyl glycidyl ether by rotary evaporation under an absolute pressure of 0.01 MPa and a water bath temperature of 85℃, and dry in a vacuum drying oven (60℃, vacuum degree -0.09 MPa) for 12 h to obtain terminal epoxy hyperbranched polysiloxane.

[0009] A preferred method for preparing supported mesoporous silica is as follows: 10 parts of mesoporous silica (SBA-15, purchased from Beijing Bailingwei Technology Co., Ltd., product number 2748670) are dispersed in 100 parts of ethanol, and 2-3 parts of 3-aminopropyltriethoxysilane are added; the reaction temperature is set at 60-70℃, the stirring speed is 600 rpm, and the reaction is carried out for 6 hours. After centrifugation, washing, and drying, aminated mesoporous silica is obtained; the aminated mesoporous silica is placed in a vacuum drying oven and mixed with 5 parts of bisphenol F type epoxy resin (model NPEF-170); the vacuum is evacuated to an absolute pressure of 0.03 MPa. a) Keep the mixture at 60℃ for 2-5 hours to allow the epoxy resin to be drawn into the mesoporous channels through capillary action. Then, transfer the mixture to a Buchner funnel lined with a microporous filter membrane. Turn on the vacuum pump to establish an extremely high negative pressure (absolute pressure ≤ 0.02 MPa). Use 12 parts of cold acetone (0-5℃) to rapidly depressurize and wash the filter cake. Under the above pressure difference, control the flow rate of cold acetone to allow it to quickly penetrate the packing layer at a flow rate of 1.5 bed volumes / minute to avoid excessive solvent retention and extraction in the channels. After drying, immediately transfer the powder to a 40℃ vacuum drying oven to remove residual solvent and obtain supported mesoporous silica.

[0010] A rapid vacuum filtration process using extremely low-temperature cold acetone combined with a high vacuum difference is employed. On one hand, the cold solvent quickly washes away free resin adhering to the outer surface of mesoporous silica. On the other hand, the powerful negative pressure drives the washing liquid to penetrate vertically through the interparticle gaps at an extremely high flow rate, depriving solvent molecules of the time to permeate into the nanopores and undergo concentration diffusion. Immediate vacuum drying after vacuum drying further interrupts the capillary extraction effect of the residual liquid film, thus achieving a clean surface while locking in the effective drug loading within the microcapsules.

[0011] When the bisphenol F epoxy resin used in this application is placed under a vacuum load environment at 60°C, its viscosity rapidly drops to a low viscosity range that allows for penetration. This extremely low viscosity state, combined with the 0.03 MPa vacuum negative pressure process, enables it to overcome steric hindrance and efficiently penetrate and store in the mesoporous channels of SBA-15 by relying on capillary action, thereby ensuring a sufficient reserve of external repair agent for subsequent microcrack repair. Furthermore, due to the significant steric hindrance restricting the amino groups anchored within the mesoporous channels and the lack of curing accelerators in the system, the crosslinking reaction between the amino groups and liquid bisphenol F epoxy resin at 60°C is in an extremely slow induction phase. During the 2-5h vacuum loading process, the degree of chemical reaction between the two is extremely low, with only very weak grafting occurring on the local pore wall surface. This weak grafting not only does not cause pore blockage but also helps the resin to initially stabilize within the pores. Most of the epoxy resin stored deep within the pores has not undergone three-dimensional crosslinking, perfectly maintaining its low viscosity and liquid fluidity. This ensures that when microcracks develop in the encapsulation material, it can flow out smoothly to provide sufficient external repair agent.

[0012] The preferred method for preparing the dual dynamic bond curing agent is as follows: 25 parts of 4,4'-diaminodiphenyl disulfide are dissolved in 160 parts of anhydrous ethanol and placed in a three-necked flask; 80 parts of ethanol solution containing 5.3-8.0 parts of terephthalaldehyde are added dropwise at a rate of 2 mL / min while stirring at 400 rpm; the reaction system is heated to 55-65℃ and reacted for 4 h; after filtration, the mixture is washed with cold water and dried under vacuum at 50℃ for 12 h, and then ground until it passes through a 300-mesh sieve to obtain an amino-terminated dual dynamic bond curing agent. The active hydrogen equivalent is determined by titration to be 119-192 g / eq.

[0013] Preferably, the stepped curing steps are as follows: in the first stage, the deaerated epoxy resin system is kept at 70-80℃ for 2 hours; in the second stage, the temperature is raised to 120℃ and kept for 2 hours; and in the third stage, the temperature is raised to 150℃ and kept for 3-6 hours.

[0014] In another aspect, the present invention provides a self-healing encapsulation material, which is prepared by any of the above preparation methods; the raw materials for preparing the self-healing encapsulation material include bisphenol A type epoxy resin, dual dynamic bond curing agent, supported mesoporous silica and terminal epoxy hyperbranched polysiloxane.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention designs and synthesizes a dual-dynamic covalent bond curing agent containing disulfide and imine bonds, breaking the intrinsic structural limitations of irreversible cross-linking of polymer networks. Due to the differentiated exchange activation energies of imine and disulfide bonds, this material possesses excellent multi-level thermal response self-healing capabilities. Dynamic exchange of imine bonds is triggered at lower temperatures, while disulfide bonds participate in breakage and recombination at slightly higher temperatures. This step-like dynamic response mechanism enables the encapsulated material to achieve efficient molecular chain segment recombination and healing at the damaged interface when subjected to external stress and micro-cracks, while maintaining overall high cross-linking density and macroscopic physical stability, thus significantly extending the material's service life.

[0016] 2. This invention transforms rigid inorganic particles into "micro-containers" with healing capabilities. By pre-treating mesoporous silica with amination, its surface is covered with active primary amine groups. During curing, these amino groups directly participate in the ring-opening crosslinking reaction of the epoxy resin, forming a strong covalent bond between the inorganic rigid filler and the organic flexible network. This eliminates interfacial gaps and compensates for the rigidity loss caused by the introduction of dynamic bonds and flexible siloxanes. Simultaneously, low-viscosity bisphenol F epoxy resin is vacuum-loaded into the internal channels of the amination-treated mesoporous silica, addressing both the macroscopic mechanical strengthening and microscopic repair agent storage requirements. When the encapsulation material is intact, the particles act as a high-strength nanoskeleton, significantly improving the tensile strength of the matrix and its barrier properties against water and oxygen. When microcracks develop inside the material, leading to stress concentration, the crack tips disrupt the particle interface, causing the liquid epoxy resin stored in the channels to be rapidly released and penetrate deep into the cracks through capillary action. This effectively solves the technical bottleneck of the difficulty in spontaneous diffusion of repair agents in high-rigidity networks.

[0017] 3. This invention introduces terminal epoxy-terminated hyperbranched polysiloxane as a key interfacial compatibility and regulation medium. Its terminal epoxy groups can form a strong covalent chemical anchor with the matrix resin, preventing the free release of additives. Meanwhile, its highly branched flexible siloxane segments construct a highly elastic "buffer transition zone" between the rigid mesoporous silica and the cross-linked resin matrix. This not only significantly alleviates the internal stress caused by volume shrinkage during thermosetting and avoids the interfacial debonding phenomenon between inorganic fillers and organic matrix, but more importantly, this highly branched spherical topology opens up abundant free volume inside the network, providing sufficient physical space for dynamic covalent bond exchange at damaged interfaces.

[0018] 4. This invention breaks through the effectiveness limit of a single repair mechanism, constructing a dual healing network that deeply coordinates the release of external aids and the movement of intrinsic chain segments. When the microcapsule releases the active diluent to fill the crack, it can not only undergo secondary cross-linking and curing with the thiol groups and residual amino groups released from the disulfide bond breakage in the matrix network, filling physical gaps; more importantly, the local swelling effect of the diluent at the crack interface greatly increases the free volume of the micro-network in this region; this swelling effect acts as a "molecular lubricant," significantly reducing the steric hindrance and energy barrier for the dynamic exchange of surrounding imine and disulfide bonds, thereby completely eliminating deep microcracks in a dual synergistic manner and restoring the protective performance of the material.

[0019] 5. The stepped temperature-controlled curing process employed in this invention achieves perfect synergy with the reaction kinetics of the dual dynamic bond material. Through pre-crosslinking in the low-temperature stage, highly reactive groups within the system are preferentially encouraged to slowly form a network, and microphase separation of polymer chain segments is guided, successfully constructing a microscopic topology of "rigid skeleton bearing stress and flexible dynamic channels responsible for repair." The subsequent medium- and high-temperature setting stage ensures the complete crosslinking of the remaining epoxy groups. This synergistic process avoids explosive polymerization and severe thermal stress caused by instantaneous high temperatures, while maximizing the preservation of the activity of dynamic covalent bonds within the network while locking in excellent macroscopic mechanical strength and dense barrier properties. Attached Figure Description

[0020] Figure 1 The figures show the test results of the self-healing performance of Examples 1-4 and Comparative Examples 1-7 of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1 This invention provides a self-healing encapsulation material and its preparation method, the technical solution of which is as follows: Example 1 Under nitrogen protection, 32.87 parts of tetra(dimethylsiloxy)silane and 130 parts of anhydrous toluene were added to a three-necked flask. Mechanical stirring was started and the stirring speed was set to 400 rpm. 0.013 parts of caster catalyst were added using a microsyringe, and the temperature was raised to 60°C. 12.63 parts of methyldiallylsilane were dissolved in 50 parts of anhydrous toluene and added dropwise to the three-necked flask at a rate of 1.5 mL / min using a constant-pressure dropping funnel. After the addition was complete, the reaction was maintained at 60°C for 4 hours. The temperature was then raised to 85°C, and the stirring speed was increased to 600 rpm. 22 parts of allyl glycidyl ether and... After mixing 30 parts of anhydrous toluene, the mixture was added dropwise to the reaction system at a uniform rate over 30 min and reacted for 5 h. The system was then naturally cooled to room temperature, and 5 parts of activated carbon were added. The mixture was stirred at 300 rpm for 30 min, and then vacuum filtered through a polytetrafluoroethylene (PTFE) membrane with a pore size of 0.22 μm. The filtrate was transferred to a rotary evaporator and the toluene solvent and unreacted excess allyl glycidyl ether were removed by rotary evaporation under an absolute pressure of 0.01 MPa and a water bath temperature of 85 °C. The filtrate was then dried in a vacuum drying oven (60 °C, vacuum degree -0.09 MPa) for 12 h to obtain terminal epoxy hyperbranched polysiloxane.

[0023] Ten parts of mesoporous silica (SBA-15) were dispersed in 100 parts of ethanol, and two parts of 3-aminopropyltriethoxysilane were added. The reaction temperature was set at 60℃, the stirring speed at 600 rpm, and the reaction was carried out for 6 hours. After centrifugation, washing, and drying, aminated mesoporous silica was obtained. The aminated mesoporous silica was placed in a vacuum drying oven and mixed with 5 parts of bisphenol F type epoxy resin (model NPEF-170). The vacuum was evacuated to an absolute pressure of 0.03 MPa and maintained at 60℃ for 2 hours, allowing the epoxy resin to be drawn in by capillary action. The mixture was then transferred to a Buchner funnel lined with a microporous filter membrane within the mesoporous channels. A vacuum pump was turned on to establish an extremely high negative pressure (absolute pressure ≤ 0.02 MPa). The filter cake was rapidly leached by vacuum filtration using 12 parts of cold acetone (0-5℃). Under the aforementioned pressure difference, the flow rate of the cold acetone was controlled to allow it to quickly penetrate the packing layer at a flow rate of 1.5 bed volumes / minute, avoiding excessive solvent retention and extraction within the channels. After drying, the powder was immediately transferred to a 40℃ vacuum drying oven to remove residual solvent, yielding supported mesoporous silica.

[0024] 25 parts of 4,4'-diaminodiphenyl disulfide were dissolved in 160 parts of anhydrous ethanol and placed in a three-necked flask. 80 parts of ethanol solution containing 5.3 parts of terephthalaldehyde were added dropwise at a rate of 2 mL / min while stirring at 400 rpm. The reaction system was heated to 55 °C and reacted for 4 h. After filtration, the mixture was washed with cold water and dried under vacuum at 50 °C for 12 h. The mixture was then ground until it passed through a 300-mesh sieve to obtain an amino-terminated double dynamic bond curing agent.

[0025] Take 100 parts of bisphenol A type epoxy resin E-51 and heat it to 60℃; add 5 parts of terminal epoxy group hyperbranched polysiloxane and 8 parts of supported mesoporous silica; use a high-shear emulsifying disperser to stir and disperse for 30 min at a speed of 2500 rpm and a temperature of 60℃ to obtain a mixture; cool the mixture to 40℃, and according to the measured active hydrogen equivalent of the dual dynamic bond curing agent, calculate based on the total epoxy group to active hydrogen molar ratio of 1:1 in the system, add 35 parts of dual dynamic bond curing agent, mix at 300 rpm for 15 min, and then degas under vacuum for 10 min to obtain a degassed epoxy resin system; perform step curing on the degassed epoxy resin system, and demold after natural cooling to room temperature to obtain a self-healing encapsulation material; the step curing steps are as follows: first, keep the degassed epoxy resin system at 70℃ for 2 h, then raise the temperature to 120℃ and keep it at 2 h, and finally raise the temperature to 150℃ and keep it at 3 h.

[0026] Example 2

[0027] Referring to the preparation method and parameters of Example 1, the differences are as follows: When preparing the terminal epoxy hyperbranched polysiloxane, the amount of allyl glycidyl ether was 25 parts, and it was added dropwise to the reaction system at a uniform rate over 30 minutes, followed by a 6-hour reaction; when preparing the supported mesoporous silica, 2.2 parts of 3-aminopropyltriethoxysilane were added, the reaction temperature was set to 65°C, and the reaction was maintained at 60°C for 3 hours after vacuuming; when preparing the double dynamic bond curing agent, 80 parts of an ethanol solution containing 6.0 parts of terephthalaldehyde were added dropwise; the reaction system was then heated... The reaction was carried out at 60℃ for 4 hours. The amount of terminal epoxy hyperbranched polysiloxane was 6.5 parts, and the amount of supported mesoporous silica was 10 parts. The mixture was stirred and dispersed at 2500 rpm and 60℃ for 40 minutes. Based on the measured active hydrogen equivalent of the dual dynamic bond curing agent, and calculated according to the molar ratio of total epoxy groups to active hydrogen in the system of 1:1, 38 parts of dual dynamic bond curing agent were added. The degassed epoxy resin system was first kept at 75℃ for 2 hours, then heated to 120℃ for 2 hours, and finally heated to 150℃ for 4 hours.

[0028] Example 3

[0029] Referring to the preparation method and parameters of Example 1, the differences are as follows: When preparing the terminal epoxy hyperbranched polysiloxane, the amount of allyl glycidyl ether was 28 parts, and it was added dropwise to the reaction system at a uniform rate over 30 minutes, followed by a 7-hour reaction; when preparing the supported mesoporous silica, 2.6 parts of 3-aminopropyltriethoxysilane were added. The reaction temperature was set at 65°C, and the reaction was maintained at 60°C for 4 hours after vacuuming; when preparing the double dynamic bond curing agent, an 80-part ethanol solution containing 7.2 parts of terephthalaldehyde was added dropwise; the reaction system... The reaction was carried out at 60℃ for 4 hours. The amount of terminal epoxy hyperbranched polysiloxane was 8 parts, and the amount of supported mesoporous silica was 13 parts. The mixture was stirred and dispersed at 2500 rpm and 60℃ for 50 minutes. Based on the measured active hydrogen equivalent of the dual dynamic bond curing agent, and calculated according to the molar ratio of total epoxy groups to active hydrogen in the system of 1:1, 42 parts of dual dynamic bond curing agent were added. The degassed epoxy resin system was first kept at 75℃ for 2 hours, then heated to 120℃ for 2 hours, and finally heated to 150℃ for 5 hours.

[0030] Example 4

[0031] The preparation method and parameters were the same as in Example 1, except that when preparing the terminal epoxy hyperbranched polysiloxane, the amount of allyl glycidyl ether was 32 parts, which was added dropwise to the reaction system at a uniform rate over 30 minutes and reacted for 8 hours; when preparing the supported mesoporous silica, 3 parts of 3-aminopropyltriethoxysilane were added, the reaction temperature was set to 70°C, and the reaction was maintained at 60°C for 5 hours after vacuuming; when preparing the double dynamic bond curing agent, 80 parts of ethanol solution containing 8.0 parts of terephthalaldehyde were added dropwise; and the reaction system was heated. The reaction was carried out at 65℃ for 4 hours. The amount of terminal epoxy hyperbranched polysiloxane was 10 parts, and the amount of supported mesoporous silica was 15 parts. The mixture was stirred and dispersed at 2500 rpm and 60℃ for 60 minutes. Based on the measured active hydrogen equivalent of the dual dynamic bond curing agent, and calculated according to the molar ratio of total epoxy groups to active hydrogen in the system of 1:1, 45 parts of dual dynamic bond curing agent were added. The degassed epoxy resin system was first kept at 80℃ for 2 hours, then heated to 120℃ and kept at 120℃ for 2 hours, and finally heated to 150℃ and kept at 150℃ for 6 hours.

[0032] Comparative Example 1

[0033] The preparation method and parameters of Example 1 were used, except that the double dynamic bond curing agent was replaced with an equal amount of 4,4'-diaminodiphenyl disulfide.

[0034] Comparative Example 2

[0035] The preparation method and parameters of Example 1 are the same, except that the supported mesoporous silica is replaced with an equal amount of ordinary SBA-15 mesoporous silica.

[0036] Comparative Example 3

[0037] The preparation method and parameters of Example 1 are the same, except that no terminal epoxy hyperbranched polysiloxane is added.

[0038] Comparative Example 4

[0039] The preparation method and parameters of Example 1 are the same, except that the terminal epoxy hyperbranched polysiloxane is replaced with an equal amount of terminal epoxy linear silicone oil (model X-22-163A).

[0040] Comparative Example 5

[0041] The preparation method and parameters of Example 1 are the same, except that the amount of terephthalaldehyde is increased to 12 parts.

[0042] Comparative Example 6

[0043] The preparation method and parameters of Example 1 are the same, except that the amount of supported mesoporous silica is increased to 25 parts.

[0044] Comparative Example 7

[0045] The preparation method and parameters of Example 1 were used, except that the step-by-step curing was cancelled and the mixture was directly placed at 150°C for 6 hours for constant curing.

[0046] Experimental Example 1: Mechanical Property Testing

[0047] Tensile strength and elongation at break were tested according to the national standard GB / T 2567-2021 "Test Methods for Properties of Resin Castings", with a tensile speed of 2 mm / min; the results are shown in Table 1.

[0048] Table 1 Mechanical property tests of Examples 1-4 and Comparative Examples 3-7

[0049] Experiment Example 2: Barrier Performance and Self-Healing Performance Test

[0050] Barrier performance test: water vapor transmission rate; tested according to national standard GB / T 1037-2021, using the cup method at 38℃ and 90% RH; the smaller the value, the better the water and oxygen barrier performance; Self-healing performance test: A standard dumbbell-shaped specimen was prepared, and the initial tensile strength was tested. Then, a microcrack with a depth of about 50% of the specimen thickness was cut in the middle of the specimen with a single-edged blade. The two parts were aligned and spliced ​​together, and placed at 80℃ for 2 hours. After cooling, the tensile strength was tested again. Repair efficiency = (tensile strength after repair / initial tensile strength) × 100%; The results are shown in Table 2.

[0051] Table 2. Barrier performance and self-healing performance tests of Examples 1-4 and Comparative Examples 1-7

[0052] As shown in Tables 1 and 2, in Comparative Example 1, replacing the dual dynamic bond curing agent with an equal amount of 4,4'-diaminodiphenyl disulfide resulted in the absence of imine bonds with low exchange activation energy. At 80°C, repair primarily relied on exogenous repair agents released from the microcapsules, and the dynamic exchange of the intrinsic network was extremely slow. In Comparative Example 2, replacing the supported mesoporous silica with an equal amount of ordinary SBA-15 mesoporous silica maintained the initial tensile strength. However, during microcrack initiation, the absence of liquid bisphenol F epoxy resin as an "exogenous repair agent" released into the crack capillaries prevented the local swelling and expansion of the internal free volume, disrupting the synergistic repair mechanism. In Comparative Example 3, the absence of terminal epoxy-terminated hyperbranched polysiloxane resulted in the lack of this crucial interfacial compatibilizer and "buffer transition zone," leading to interfacial defects between the inorganic filler and the matrix resin, causing a decrease in tensile strength. Simultaneously, the overly dense and rigid matrix network restricted the movement of molecular chain segments in the dynamic bonds. In Comparative Example 4, the terminal epoxy hyperbranched polysiloxane was replaced with an equal amount of terminal epoxy linear silicone oil. The linear siloxane chains easily became entangled in the resin network, unable to forcibly expand the three-dimensional "free volume" cavity at the microscale like hyperbranched spherical molecules. This resulted in a significant reduction in the molecular lubrication effect, macroscopically manifesting as lower toughness and repair efficiency compared to Example 1. In Comparative Example 5, the amount of terephthalaldehyde was increased to 12 parts, resulting in a severe excess of aldehyde groups. This excessively consumed the primary amine groups in the system, leaving insufficient active hydrogen to support the bisphenol A epoxy resin to complete dense three-dimensional cross-linking and curing. This led to numerous unreacted cross-linking defects in the resin network, causing the material to become soft and sticky, and resulting in the failure of its mechanical and barrier properties. In Comparative Example 6, the amount of supported mesoporous silica was increased to 25 parts, and the amount of nano-inorganic particles exceeded the dispersion limit of the system. Severe agglomeration still occurred under high shear. These agglomerates acted as stress concentration points and defect channels for water and oxygen permeation within the matrix. When the material was stretched, microcracks preferentially initiated and rapidly propagated around these agglomerates, causing the material to fracture before it could undergo plastic deformation. This resulted in a sharp decrease in the material's elongation at break and a significant increase in water vapor permeability. In Comparative Example 7, the stepped curing process was eliminated, and the material was directly placed at 150°C for 6 hours for constant temperature curing. This direct high-temperature explosive curing caused extremely high thermal shrinkage internal stress within the material. This not only failed to form an ordered "rigid skeleton-flexible channel" microphase separation topology, but also directly induced micro-cracks within the material. When stretched, the stress intensity factor at the crack tip of the brittle material with microcracks instantly reached a critical value, directly leading to catastrophic fracture and severely weakening the material's intrinsic tensile strength and water vapor barrier capacity.

[0053] In summary, conventional single modification methods—such as introducing only dynamic disulfide bonds, adding only rigid nanofillers, or using conventional linear toughening agents—cannot simultaneously achieve both the macroscopic strength and low-temperature rapid healing capability of the encapsulation material. This invention constructs a multi-scale synergistic network: at the molecular scale, a microphase separation structure of "rigid cross-linked framework + locally high free volume" is constructed using dual dynamic covalent bonds (disulfide / imine bonds) and terminal epoxy-based hyperbranched polysiloxanes; at the microscale, mesoporous silica is transformed into spontaneously releasing "micro-containers"; at the process level, stepwise temperature control perfectly matches the response kinetics of chemical bonds; this dual synergy of "intrinsic chain segment movement + exogenous swelling cross-linking" achieves a simultaneous improvement in high cross-linking density (mechanical / barrier properties) and high molecular chain segment mobility (self-healing efficiency).

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a self-healing encapsulation material, characterized in that: The preparation method is as follows: bisphenol A type epoxy resin is heated; terminal epoxy hyperbranched polysiloxane and supported mesoporous silica are added; the mixture is stirred and dispersed using a high-shear emulsifying disperser; after cooling the mixture, a dual dynamic bond curing agent is added, and after mixing, vacuum degassing is performed to obtain a degassed epoxy resin system; the degassed epoxy resin system is subjected to step curing, and after natural cooling to room temperature, it is demolded to obtain the self-healing encapsulation material; The supported mesoporous silica is prepared from mesoporous silica, 3-aminopropyltriethoxysilane and bisphenol F type epoxy resin; The dual dynamic bond curing agent is prepared from 4,4'-diaminodiphenyl disulfide and terephthalaldehyde.

2. The method for preparing a self-healing encapsulation material according to claim 1, characterized in that: The preparation method of the terminal epoxy hyperbranched polysiloxane is as follows: under nitrogen protection, tetrakis(dimethylsiloxy)silane and anhydrous toluene are added to a three-necked flask and stirred; after adding a Castells catalyst, the temperature is raised; methyl diallylsilane is dissolved in the anhydrous toluene and added dropwise to the three-necked flask through a constant pressure dropping funnel; the temperature is raised and the stirring speed is increased, and allyl glycidyl ether is mixed with the anhydrous toluene and added dropwise to the reaction system for 5-8 hours; after naturally cooling to room temperature, activated carbon is added and stirred, and after vacuum filtration, rotary evaporation and drying are performed to obtain the terminal epoxy hyperbranched polysiloxane.

3. The method for preparing a self-healing encapsulation material according to claim 1, characterized in that: The method for preparing the supported mesoporous silica is as follows: the mesoporous silica is dispersed in ethanol, and 3-aminopropyltriethoxysilane is added; the reaction temperature is set to 60-70℃, and after the reaction, the silica is centrifuged, washed, and dried to obtain aminated mesoporous silica; the aminated mesoporous silica is placed in a vacuum drying oven and mixed with bisphenol F epoxy resin; after vacuuming, the reaction is carried out for 2-5 hours, and then washed with acetone to obtain the supported mesoporous silica.

4. The method for preparing a self-healing encapsulation material according to claim 1, characterized in that: The high-shear emulsifying and dispersing machine has a stirring and dispersing time of 30-60 minutes.

5. The method for preparing a self-healing encapsulation material according to claim 1, characterized in that: The preparation method of the dual dynamic bond curing agent is as follows: the 4,4'-diaminodiphenyl disulfide is dissolved in anhydrous ethanol and placed in a three-necked flask; an ethanol solution containing the terephthalaldehyde is added dropwise; the reaction system is heated to 55-65℃ and reacted; after filtration, it is washed with cold water and dried under vacuum to obtain the dual dynamic bond curing agent.

6. The method for preparing a self-healing encapsulation material according to claim 1, characterized in that: The stepped curing steps are as follows: in the first stage, the defoamed epoxy resin system is kept at 70-80℃ for 2 hours; in the second stage, the temperature is raised to 120℃ and kept for 2 hours; and in the third stage, the temperature is raised to 150℃ and kept for 3-6 hours.

7. A self-healing encapsulation material, characterized in that: The self-healing encapsulation material is prepared by the preparation method described in any one of claims 1-6; the raw materials for preparing the self-healing encapsulation material include bisphenol A type epoxy resin, dual dynamic bond curing agent, supported mesoporous silica and terminal epoxy hyperbranched polysiloxane.

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