Composite epoxy resin material and preparation method thereof

Abstract

The invention discloses a composite epoxy resin material and a preparation method thereof. The composite epoxy resin material comprises 60-70 wt% of epoxy resin, 15-20 wt% of a cross-linking agent, 9-12 wt% of composite microcapsules, 5-6 wt% of piezoelectric nanoparticles and 1-2 wt% of an accelerant. Wherein the composite microcapsule is formed by a rod-shaped substrate made of magnetic doped epoxy resin, and an epoxy core material, an inner shell layer, a cured core material and an outer shell layer are sequentially coated on the rod-shaped substrate. According to the composite epoxy resin material disclosed by the invention, the composite microcapsules are used, and the piezoelectric nanoparticles and the polyether amine D2000 are combined, so that macroscopic cracks can be repaired by utilizing the microcapsules, molecular-level damage can be repaired by utilizing a dynamic bond network, and dual repair of the composite epoxy resin material is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and in particular to a composite epoxy resin material and a preparation method thereof. Background Art

[0002] In recent years, epoxy resin has been widely used in the field of sports equipment manufacturing due to its high strength, lightweight and excellent fatigue resistance. For example, it is used in key structural components such as high-end tennis racket frames, carbon fiber bicycle frames, and golf club heads. However, traditional epoxy resin materials still face the following technical bottlenecks in practical applications:

[0003] 1) Dynamic damage accumulation is irreversible: Sports equipment is prone to microcracks and interface debonding under dynamic loads such as repeated impact and bending. Traditional epoxy resins lack the ability to repair themselves, resulting in continued expansion of damage.

[0004] 2) Performance deterioration in hot and humid environments: When outdoor sports equipment is exposed to hot and humid environments for a long time, moisture penetration will weaken the resin-fiber interface bonding strength.

[0005] 3) Limitations of local repair technology: Existing damage repair methods (such as external reinforcement sheets or injection resin filling) require manual intervention, are complex to operate, and are difficult to restore the original mechanical properties.

[0006] Therefore, a new composite epoxy resin material is needed to solve the problems faced by existing traditional epoxy resin materials in practical applications. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a composite epoxy resin material and a preparation method.

[0008] The technical solution of the present invention is: a composite epoxy resin material, comprising: 60-70wt% epoxy resin, 15-20wt% crosslinking agent, 9-12wt% composite microcapsules, 5-6wt% piezoelectric nanoparticles and 1-2wt% accelerator; the composite microcapsules are composed of a rod-shaped matrix made of magnetically doped epoxy resin, and an epoxy core material, an inner shell layer, a cured core material and an outer shell layer are sequentially coated on the rod-shaped matrix; the epoxy core material is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2:2-5; the cured core material is a mixture of isophorone diisocyanate (IPDI) and terminal isocyanate prepolymer (CPU) in a mass ratio of 4:8-10; and the inner shell layer and the outer shell layer are both made of phenolic resin.

[0009] Description: The present invention constructs dual-core microcapsules (wrapping epoxy core material and cured core material), which can be used to repair macro cracks. By adding piezoelectric nanoparticles, a local electric field can be generated when the material is impacted, thereby accelerating the response of microcapsule rupture and improving the repair efficiency and repair effect.

[0010] Furthermore, the preparation method of the composite microcapsule is:

[0011] S1-1. Weigh 30-40 parts by mass of epoxy core material or cured core material, 5-10 parts of Tween 80 emulsifier, and 30-80 parts of deionized water, mix them, and stir at 2000-4000 rpm for 20-30 minutes to obtain epoxy emulsion and cured emulsion, respectively.

[0012] S1-2. A rod-shaped substrate having a length of 50±10 μm and a diameter of 20-30 μm is mixed with a sufficient amount of epoxy emulsion and placed in a square reaction dish. A fixed magnetic field of 1-2 T is applied to one set of opposite side walls of the square reaction dish, and stirring is performed by reciprocating stirring along the other set of opposite side walls. The reaction is carried out at a constant temperature of 35±1° C. for 2-3 hours. During this time, 1% sodium lignin sulfonate can be added to adjust the diameter to 70-90 μm to obtain a first reaction solution. The first reaction solution is then washed with deionized water and filtered to dryness. The microcapsule base powder is coated with an inner shell layer of 10±2 μm to obtain a rod-like microcapsule base powder.

[0013] S1-3. Mix the microcapsule base powder with a sufficient amount of epoxy emulsion and place it in a circular reaction dish. Apply a rotating magnetic field of 1 to 2 T at 30 to 60 rpm to the side wall of the circular reaction dish, stir thoroughly, and react at a constant temperature of 35±1°C for 2 to 3 hours. During this period, 1% sodium lignin sulfonate can be added to adjust the particle size to 140 to 170 μm to obtain a second reaction solution. Subsequently, the second reaction solution is washed with deionized water and filtered to dry. The microcapsule base powder is coated with a shell layer of 10±2 μm to obtain spherical composite microcapsules.

[0014] Description: By using dual-type reaction vessels (square reaction vessel and round reaction vessel) combined with the configuration design of composite microcapsules, the effect of dual-core microcapsules in composite epoxy resin materials can be significantly improved. Compared with microcapsules with spherical inner and outer cores, the efficiency of repairing macro cracks is significantly improved.

[0015] Furthermore, the epoxy resin is any one of bisphenol A epoxy resin, bisphenol F epoxy resin, and glycidylamine epoxy resin.

[0016] Description: Bisphenol A epoxy resin has good mechanical strength, electrical insulation and chemical corrosion resistance, and is particularly suitable for scenarios with high requirements for comprehensive material performance. It is also rich in varieties and can be easily modified to meet different needs; bisphenol F epoxy resin has a higher benzene ring content and better corrosion resistance than bisphenol A. It has better stability in outdoor or humid environments and is suitable for long-term exposure weather resistance applications; glycidylamine epoxy resin molecules contain multiple epoxy groups and have a fast curing speed, making it suitable for processes that require rapid prototyping. It also has a high cross-linking density and maintains good mechanical properties even at high temperatures. After curing, the structure is dense, and the mechanical strength and hardness are significantly improved, making it suitable for the manufacture of high-performance composite materials.

[0017] Furthermore, the cross-linking agent is polyetheramine D2000.

[0018] Description: By using a polyetheramine curing agent containing dynamic disulfide bonds, the construction of a dynamic bond network in the composite epoxy resin material can be achieved simultaneously, thereby using microcapsules to repair macro cracks and the dynamic bond network to repair molecular-level damage, thereby achieving dual repair of the composite epoxy resin material and enhancing the self-healing efficiency of the composite epoxy resin material.

[0019] Furthermore, the accelerator is any one of tetrabutylammonium bromide, benzyldimethylamine, and 2-ethyl-4-methylimidazole.

[0020] Note: The use of accelerators can change the reaction mechanism between epoxy resin and curing agent, reduce the reaction activation energy, significantly increase the cross-linking reaction rate, and improve the overall performance of the cured product by optimizing the cross-linking network structure. However, these accelerators are not limited to the above-mentioned ones and can be selected according to the actual curing agent used. For example, benzyldimethylamine is suitable for anhydride curing agents.

[0021] Furthermore, the doping amount of magnetic powder in the magnetic-doped epoxy resin is 30-50 wt %, the particle size of the magnetic powder is 5-10 μm, and the epoxy resin in the magnetic-doped epoxy resin is any one of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0022] Description: By using magnetically doped epoxy resin as the building material of the rod-shaped matrix, the preparation requirements of composite microcapsules can be met, thereby configuring a rod-shaped microcapsule base powder. In the above-mentioned doping amount, the configuration requirements of the rod-shaped matrix can be maintained while satisfying the influence of the magnetic field.

[0023] Furthermore, the piezoelectric nanoparticles are ZnO@BaTiO3.

[0024] Description: By adding piezoelectric nanoparticles, such as ZnO@BaTiO3 core-shell structure, a local electric field can be generated when the composite epoxy resin material is impacted, thereby accelerating the response of microcapsule rupture or accelerating the synergistic response of dynamic bond recombination and microcapsule rupture, thereby improving the self-healing efficiency and effect of the composite epoxy resin material.

[0025] Furthermore, the piezoelectric nanoparticles are coated, specifically: the piezoelectric nanoparticles are placed in a honeycomb mill, and a silane coupling agent accounting for 5-10% of the mass of the piezoelectric nanoparticles is intermittently sprayed, and the temperature is controlled at 60-70°C, and the intermittent spraying is spraying for 2 seconds and stopping for 3-5 seconds.

[0026] Description: By coating the piezoelectric nanoparticles, the interfacial bonding strength between the piezoelectric nanoparticles and the epoxy resin material can be significantly improved. Its low viscosity characteristics can promote the uniform dispersion of the nanoparticles in the resin, reduce agglomeration, avoid performance deterioration caused by stress concentration, and reduce the generation of bubbles and defects in the material, thereby improving the efficiency of the molding process.

[0027] The present invention also provides a method for preparing a composite epoxy resin material, comprising the following steps:

[0028] S1, prepare composite microcapsules for standby use;

[0029] S2, stirring the epoxy resin and the crosslinking agent at 50-60° C. and a vacuum degree of -0.08 MPa for 1-2 hours to obtain a resin base liquid;

[0030] S3. Alternately add piezoelectric nanoparticles and composite microcapsules to the resin base liquid, with the single addition amount accounting for 5-10% of the total amount of each. Stir at 1400-1800 rpm for 30-60 minutes and control the temperature below 38° C. to obtain a composite epoxy resin material.

[0031] Description: The composite epoxy resin material of the present invention can be effectively prepared by adopting the above method. The composite epoxy resin material of the present invention can have a faster self-repair response efficiency by using composite microcapsules, combined with piezoelectric nanoparticles and polyetheramine D2000, providing a new choice for self-repairing materials.

[0032] At the same time, by alternately adding piezoelectric nanoparticles and composite microcapsules, the piezoelectric nanoparticles and composite microcapsules can be dispersed more evenly in the composite epoxy resin material, avoiding the deterioration of performance caused by stress concentration, and can also reduce the generation of bubbles and defects in the material to a certain extent, thereby improving the production and processing performance of the composite epoxy resin material.

[0033] Furthermore, in S2 , a variable magnetic field of 0.4 to 0.8 T is added during the stirring period, and the variable magnetic field is reciprocated between 0.4 and 0.8 T at an enhancement / decay rate of ±0.1 to 0.2 T / min.

[0034] Description: By using a variable magnetic field to combine the rod-shaped matrix of the composite microcapsules, the composite microcapsules are arranged, so that the piezoelectric nanoparticles and composite microcapsules are more evenly distributed in the composite epoxy resin material, avoiding agglomeration and ensuring the performance of the composite epoxy resin material.

[0035] The beneficial effects of the present invention are:

[0036] (1) By using composite microcapsules in the composite epoxy resin material of the present invention and combining piezoelectric nanoparticles and polyetheramine D2000, the microcapsules can be used to repair macro cracks and the dynamic bond network can be used to repair molecular-level damage, thereby achieving dual repair of the composite epoxy resin material.

[0037] (2) By adding piezoelectric nanoparticles to the composite epoxy resin material of the present invention, a local electric field can be generated when the material is impacted, accelerating the coordinated response of dynamic bond recombination and microcapsule rupture, so that the composite epoxy resin material has a faster self-repair response efficiency, thereby providing a new choice for self-repairing materials.

[0038] (3) The preparation method of the present invention can significantly enhance the use effect of the prepared composite microcapsules by using a dual-type reaction vessel in different configuration stages and combining the configuration design of the composite microcapsules, thereby significantly improving the repair efficiency of macro cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the synthesis route of the composite microcapsules of the present invention.

[0040] Figure 2 It is a structural schematic diagram of the square reaction vessel of the present invention.

[0041] Figure 3 It is a structural schematic diagram of a circular reaction vessel of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below in conjunction with specific implementation methods to better demonstrate the advantages of the present invention.

[0043] Example 1: A composite epoxy resin material comprising: 65 wt% epoxy resin, 18 wt% cross-linking agent, 10 wt% composite microcapsules, 5.5 wt% piezoelectric nanoparticles, and 1.5 wt% accelerator;

[0044] The epoxy resin is a glycidylamine epoxy resin; the crosslinking agent is polyetheramine D2000; the accelerator is tetrabutylammonium bromide; the piezoelectric nanoparticles are ZnO@BaTiO3;

[0045] The composite microcapsule comprises a rod-shaped matrix made of magnetically doped epoxy resin, which is coated with an epoxy core material, an inner shell layer, a cured core material, and an outer shell layer in sequence. The epoxy core material is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 1:2; the cured core material is a mixture of isophorone diisocyanate (IPDI) and a terminal isocyanate prepolymer (CPU) in a mass ratio of 4:9; and both the inner and outer shell layers are made of phenolic resin. The magnetic powder in the magnetically doped epoxy resin is doped at a concentration of 47% by weight, has a particle size of 5 to 10 μm, and is made of bisphenol A epoxy resin.

[0046] The preparation method of the composite epoxy resin material comprises the following steps:

[0047] S1, prepare composite microcapsules, such as Figure 1 As shown,

[0048] S1-1. Weigh 35 parts by mass of epoxy core material or cured core material, 7 parts by mass of Tween 80 emulsifier, and 70 parts by mass of deionized water, mix them, and stir at 3500 rpm for 25 minutes to obtain epoxy emulsion and cured emulsion, respectively.

[0049] S1-2, mix a rod-shaped substrate with a length of 50±10μm and a diameter of 20-30μm with a sufficient amount of epoxy emulsion and place it in a square reaction dish, such as Figure 2 As shown, a fixed magnetic field of 1.5 T is applied to one set of opposite side walls of a square reaction dish, and stirring is performed by reciprocating stirring along the other set of opposite side walls at a stirring rate of 120 times / min ("time" refers to one reciprocating stirring). The reaction is carried out at a constant temperature of 35±1°C for 2.5 hours, during which 1% sodium lignin sulfonate can be added to adjust the diameter to 70-90 μm to obtain a first reaction solution. The first reaction solution is then washed with deionized water and filtered to dryness, and the microcapsule base powder is coated with an inner shell layer of 10±2 μm to obtain a rod-like microcapsule base powder.

[0050] S1-3, the microcapsule base powder is mixed with a sufficient amount of epoxy emulsion and placed in a round reaction dish, as shown in FIG. Figure 3As shown, a rotating magnetic field of 1.5 T at 50 rpm is applied to the side wall of the circular reaction dish, and the mixture is fully stirred at a stirring rate of 300 rpm. The reaction is carried out at a constant temperature of 35±1°C for 2.5 hours. During this period, 1% sodium lignin sulfonate can be added to adjust the particle size to 140-170 μm to obtain a second reaction solution. The second reaction solution is then washed with deionized water and filtered to dryness, and the microcapsule base powder is coated with a 10±2 μm shell layer to obtain spherical composite microcapsules.

[0051] S2, stirring the epoxy resin and the crosslinking agent at 55° C. and a vacuum degree of -0.08 MPa for 1.5 h to obtain a resin base liquid;

[0052] S3. Alternately add piezoelectric nanoparticles and composite microcapsules to the resin base liquid, with the single addition amount accounting for 5% of the total amount of each. During the period, stir at 1600 rpm for 50 minutes, and control the temperature at 35°C to obtain a composite epoxy resin material. Then, inject the composite epoxy resin material into the corresponding sports equipment mold (for example: tennis racket frame) for production and processing. Specifically: at a mold temperature of 78°C, an injection pressure of 140 MPa, a holding time of 80s, and a cooling rate of 3°C / min, a self-healing reinforced tennis racket frame of the required composite epoxy resin material is prepared.

[0053] Example 2: This example differs from Example 1 in that the composite epoxy resin material includes: 60 wt % epoxy resin, 20 wt % cross-linking agent, 12 wt % composite microcapsules, 6 wt % piezoelectric nanoparticles and 2 wt % accelerator.

[0054] Example 3: This example is different from Example 1 in that the composite epoxy resin material includes: 70 wt% epoxy resin, 15 wt% cross-linking agent, 9 wt% composite microcapsules, 5 wt% piezoelectric nanoparticles and 1 wt% accelerator.

[0055] Example 4: The difference between this example and Example 1 is that, in the composite microcapsule, the epoxy core material is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 1:1; the curing core material is a mixture of isophorone diisocyanate (IPDI) and terminal isocyanate prepolymer (CPU) in a mass ratio of 1:2; the doping amount of magnetic powder in the magnetic-doped epoxy resin is 30wt%, the particle size of the magnetic powder is 5-10μm, and the epoxy resin in the magnetic-doped epoxy resin is bisphenol A epoxy resin.

[0056] Example 5: The difference between this example and Example 1 is that, in the composite microcapsule, the epoxy core material is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2:5; the curing core material is a mixture of isophorone diisocyanate (IPDI) and terminal isocyanate prepolymer (CPU) in a mass ratio of 2:5; the doping amount of magnetic powder in the magnetic-doped epoxy resin is 50wt%, the particle size of the magnetic powder is 5 to 10μm, and the epoxy resin in the magnetic-doped epoxy resin is bisphenol A epoxy resin.

[0057] Example 6: This example is different from Example 1 in that, in S1-1, 30 parts of epoxy core material or cured core material, 5 parts of Tween 80 emulsifier, and 30 parts of deionized water are weighed by mass, mixed, and stirred at 2000 rpm for 20 minutes to obtain epoxy emulsion and cured emulsion, respectively.

[0058] Example 7: This example is different from Example 1 in that, in S1-1, 40 parts of epoxy core material or cured core material, 10 parts of Tween 80 emulsifier, and 80 parts of deionized water are weighed, mixed, and stirred at 4000 rpm for 30 minutes to obtain epoxy emulsion and cured emulsion, respectively.

[0059] Example 8: This example differs from Example 1 in that, in S1-2, a rod-shaped substrate with a length of 50±10 μm and a diameter of 20-30 μm is mixed with a sufficient amount of epoxy emulsion and placed in a square reaction dish, and a fixed magnetic field of 1 T is applied to a set of opposite side walls of the square reaction dish.

[0060] Example 9: This example differs from Example 1 in that, in S1-2, a rod-shaped substrate with a length of 50±10 μm and a diameter of 20 to 30 μm is mixed with a sufficient amount of epoxy emulsion and placed in a square reaction dish, and a fixed magnetic field of 2 T is applied to a set of opposite side walls of the square reaction dish.

[0061] Example 10: This example is different from Example 1 in that, in S1-3, the microcapsule base powder is mixed with a sufficient amount of epoxy emulsion and placed in a circular reaction dish, and a rotating magnetic field of 30 rpm and 1 T is applied to the side wall of the circular reaction dish.

[0062] Example 11: This example differs from Example 1 in that, in S1-3, the microcapsule base powder is mixed with a sufficient amount of epoxy emulsion and placed in a circular reaction dish, and a rotating magnetic field of 60 rpm and 2 T is applied to the side wall of the circular reaction dish.

[0063] Example 12: This example is different from Example 1 in that, in S2, the epoxy resin and the cross-linking agent are stirred at 50° C. and a vacuum degree of -0.08 MPa for 1 h to obtain a resin base liquid.

[0064] Example 13: This example is different from Example 1 in that, in S2, the epoxy resin and the cross-linking agent are stirred at 60° C. and a vacuum degree of -0.08 MPa for 2 h to obtain a resin base liquid.

[0065] Example 14: This example is different from Example 1 in that, in S3, piezoelectric nanoparticles and composite microcapsules are added alternately, with the single addition amount accounting for 5% of the total amount of each, during which the mixture is stirred at 1400 rpm for 30 minutes and the temperature is controlled at 35°C to obtain a composite epoxy resin material.

[0066] Example 15: This example is different from Example 1 in that, in S3, piezoelectric nanoparticles and composite microcapsules are added alternately, with the single addition amount accounting for 10% of the total amount of each. During this period, stirring is carried out at 1800 rpm for 60 minutes, and the temperature is controlled at 35°C to obtain a composite epoxy resin material.

[0067] Example 16: The difference between this example and Example 1 is that the piezoelectric nanoparticles are coated, specifically: the piezoelectric nanoparticles are placed in a honeycomb mill, and the silane coupling agent accounting for 8% of the mass of the piezoelectric nanoparticles is intermittently sprayed, and the temperature is controlled at 65°C. The intermittent spraying is spraying for 2 seconds and stopping for 4 seconds.

[0068] Example 17: This example differs from Example 16 in that a silane coupling agent accounting for 5% of the mass of the piezoelectric nanoparticles is sprayed intermittently, and the temperature is controlled at 60°C. The intermittent spraying is spraying for 2 seconds and stopping for 3 seconds.

[0069] Example 18: This example differs from Example 16 in that a silane coupling agent accounting for 10% of the mass of the piezoelectric nanoparticles is sprayed intermittently, and the temperature is controlled at 70°C. The intermittent spraying is spraying for 2 seconds and stopping for 5 seconds.

[0070] Example 19: This example differs from Example 1 in that, in S2, a variable magnetic field of 0.4 to 0.8 T is added during stirring, and the variable magnetic field fluctuates back and forth between 0.4 and 0.8 T at an enhancement / attenuation rate of ±0.1 T / min.

[0071] Example 20: This example differs from Example 19 in that the variable magnetic field varies back and forth between 0.4 and 0.8 T at an enhancement / attenuation rate of ±0.2 T / min.

[0072] Application test examples:

[0073] Verify the self-repair ability of the material after damage, including mechanical property recovery, crack healing effect and multiple repair effects.

[0074] The composite epoxy resin material of Example 1 and the material prepared by the preparation method of Example 2 are used as the benchmark test group, and the operation is as follows:

[0075] 1. Damage introduction: Prefabricate a 2mm crack using ASTM D5045 standard; impact damage, using a drop weight impact tester to produce microcracks with an energy of 1-5J;

[0076] 2. Restoration condition setting: Treat in a hot and humid environment of 80℃ and 60%RH for 24 hours to simulate a hot and humid repair environment.

[0077] 3. Verification of repair effect: The recovery rate is calculated using a three-point bending test. The same sample is subjected to three impact damage-repair cycles, and the attenuation of the repair efficiency is tested. The repair efficiency is calculated as follows:

[0078]

[0079] At the same time, a control test group was set up. The control test group used isocyanate microcapsules with an average diameter of 100 μm, which replaced the composite microcapsules of the present invention in equal amounts. The results are shown in Table 1 below:

[0080] Table 1 Composite epoxy resin material repair test results

[0081] First-time repair efficiency The third repair efficiency Baseline test group 107％ 91％ Control group 101％ 73％

[0082] As can be seen from the results in Table 1 above, the repair efficiency of the composite epoxy resin material of the present invention meets the standard requirements for super repair, and its repair efficiency decays less after multiple repairs. By comparison with other microcapsules used in the control test group, the present invention has obvious advantages in the problem of repair efficiency decay after multiple repairs.

[0083] At the same time, in order to verify the influence of various parameters on the performance of the composite epoxy resin material of the present invention, the following test groups and experimental explorations are set up as follows:

[0084] 1) Influence of the composition of composite epoxy resin materials on the performance of composite epoxy resin materials

[0085] Test 1: 60 wt% epoxy resin, 20 wt% polyetheramine D2000, 12 wt% composite microcapsules, 6 wt% piezoelectric nanoparticles, and 2 wt% tetrabutylammonium bromide;

[0086] Test 2: 70 wt% epoxy resin, 15 wt% polyetheramine D2000, 9 wt% composite microcapsules, 5 wt% piezoelectric nanoparticles, and 1 wt% tetrabutylammonium bromide;

[0087] The above test method was used for testing, and the results are shown in Table 2 below:

[0088] Table 2 Composite epoxy resin material repair test results

[0089] First-time repair efficiency The third repair efficiency Test 1 109％ 94％ Test 2 104％ 89％

[0090] From the results in Table 2 above, it can be seen that the repair efficiency is improved to a certain extent after increasing the content of polyetheramine D2000, composite microcapsules, and piezoelectric nanoparticles. However, compared with the benchmark test example, the improvement is not obvious. The production cost of Test 1 is higher. Therefore, corresponding selection can be made according to actual production and use needs.

[0091] 2) Effect of the composition of composite microcapsules on the properties of composite epoxy resin materials

[0092] Test 3: The epoxy core material was a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 1:1; the curing core material was a mixture of isophorone diisocyanate and isocyanate-terminated prepolymer in a mass ratio of 1:2;

[0093] Test 4: The epoxy core material was a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2:5; the curing core material was a mixture of isophorone diisocyanate and isocyanate-terminated prepolymer in a mass ratio of 2:5;

[0094] At the same time, control 1 was set up, in which the epoxy core material was bisphenol A epoxy resin and the curing core material was isophorone diisocyanate;

[0095] The above test method was used for testing, and the results are shown in Table 3 below:

[0096] Table 3 Composite epoxy resin material repair test results

[0097] First-time repair efficiency The third repair efficiency Test 3 105％ 87％ Test 4 107％ 85％ Control 1 98％ 81％

[0098] As can be seen from the results in Table 3 above, changing the material combination of the epoxy core material and the cured core material has a certain impact on the performance of the prepared composite microcapsules. Among them, the performance of the benchmark test example is relatively optimal. At the same time, by comparing the benchmark test example with the control 1, after using a single epoxy core material or a cured core material, the repair efficiency of the multiple repairs is significantly reduced. Therefore, the epoxy core material and the cured core material combination of the present invention can make the composite microcapsules have better performance.

[0099] 3) Effect of the preparation method of composite microcapsules on the properties of composite epoxy resin materials

[0100] Experiment 5: In S1-2, a fixed magnetic field of 1 T was applied to a set of opposite side walls of the square reaction vessel. In S1-3, a rotating magnetic field of 1 T at 30 rpm was applied to the side walls of the circular reaction vessel.

[0101] Experiment 6: In S1-2, a fixed magnetic field of 2 T was applied to a set of opposite side walls of the square reaction vessel. In S1-3, a rotating magnetic field of 2 T at 60 rpm was applied to the side walls of the circular reaction vessel.

[0102] At the same time, a control 2 was set up, in which no magnetic field was applied, and spherical composite microcapsules were constructed in both S1-2 and S1-3;

[0103] The above test method was used for testing, and the results are shown in Table 4 below:

[0104] Table 4 Composite epoxy resin material repair test results

[0105] First-time repair efficiency The third repair efficiency Test 5 104％ 88％ Test 6 107％ 92％ Control 2 102％ 80％

[0106] It can be seen from the results in Table 4 above that after changing the preparation method of the composite microcapsules, the structural configuration of the composite microcapsules is affected. Among them, the performance of Experiment 6 and the benchmark test example is relatively optimal, but the parameter requirements of Experiment 6 are higher, that is, the production cost performance is poor. Therefore, the preparation method of the composite microcapsules using the benchmark test example is relatively optimal. At the same time, by comparing the benchmark test example with the control 2, after changing the structural configuration of the composite microcapsules, the repair efficiency of the multiple repairs is significantly reduced. Therefore, the structural configuration of the composite microcapsules of the present invention can make the composite microcapsules have better performance.

[0107] 4) Effect of coating treatment of piezoelectric nanoparticles on the properties of composite epoxy resin materials

[0108] Test 7: Piezoelectric nanoparticles were placed in a honeycomb mill, and silane coupling agent accounting for 8% of the mass of the piezoelectric nanoparticles was intermittently sprayed into the mill. The temperature was controlled at 65°C, and the intermittent spraying was performed with a spraying time of 2 seconds and a rest time of 4 seconds.

[0109] Test 8: Silane coupling agent accounting for 5% of the mass of the piezoelectric nanoparticles was intermittently sprayed, and the temperature was controlled at 60°C. The intermittent spraying was performed with a spraying time of 2 seconds and a rest time of 3 seconds.

[0110] Test 9: 10% of the mass of the piezoelectric nanoparticles was sprayed intermittently with a silane coupling agent, the temperature being controlled at 70°C, with the intermittent spraying being a 2-second spray and a 5-second pause.

[0111] The above test method was used for testing, and the results are shown in Table 5 below:

[0112] Table 5 Composite epoxy resin material repair test results

[0113] First-time repair efficiency The third repair efficiency Test 7 113％ 97％ Test 8 111％ 95％ Test 9 113％ 94％

[0114] It can be seen from the results in Table 5 above that after the piezoelectric nanoparticles are coated, the performance of the composite epoxy resin material is further improved. At the same time, through the comparison of Test 8, Test 9 and Test 7, it can be seen that after changing the process parameters such as the injection amount of the silane coupling agent, the performance of the composite epoxy resin material has declined to a certain extent, among which the coating treatment effect of Test 7 is the best.

[0115] 5) Influence of composite epoxy resin material preparation method on its performance

[0116] Test 10: In S2, a variable magnetic field of 0.4 to 0.8 T was added during the stirring period. The variable magnetic field was reciprocated between 0.4 and 0.8 T at an increase / decay rate of ±0.1 T / min.

[0117] Experiment 11: In S2, a variable magnetic field of 0.4 to 0.8 T was added during stirring, and the variable magnetic field was reciprocated between 0.4 and 0.8 T at an increase / decay rate of ±0.2 T / min.

[0118] The above test method was used for testing, and the results are shown in Table 6 below:

[0119] Table 6 Composite epoxy resin material repair test results

[0120] First-time repair efficiency The third repair efficiency Test 10 109％ 97％ Test 11 107％ 94％

[0121] It can be seen from the results in Table 6 above that after adjusting the preparation method of the composite epoxy resin material, the improvement in its first repair efficiency has changed to a certain extent, but it is not obvious. However, its repair efficiency of multiple repairs has been improved to a certain extent. It can be seen that the introduction of a variable magnetic field during stirring can effectively improve the repair efficiency of the composite epoxy resin material in multiple repairs.

Claims

1. A composite epoxy resin material, characterized in that: include: 60-70 wt% epoxy resin, 15-20 wt% cross-linking agent, 9-12 wt% composite microcapsules, 5-6 wt% piezoelectric nanoparticles and 1-2 wt% accelerator; The composite microcapsule is composed of a rod-shaped matrix made of magnetically doped epoxy resin, on which an epoxy core material, an inner shell layer, a cured core material, and an outer shell layer are sequentially coated; The epoxy core material is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2:2 to 5; the curing core material is a mixture of isophorone diisocyanate and terminal isocyanate prepolymer in a mass ratio of 4:8 to 10; the inner shell layer and the outer shell layer are both made of phenolic resin.

2. A composite epoxy resin material according to claim 1, characterized in that: The preparation method of the composite microcapsule is as follows: S1-1. Weigh 30-40 parts by mass of epoxy core material or cured core material, 5-10 parts of Tween 80 emulsifier, and 30-80 parts of deionized water, mix them, and stir at 2000-4000 rpm for 20-30 minutes to obtain epoxy emulsion and cured emulsion, respectively. S1-2. A rod-shaped substrate having a length of 50±10 μm and a diameter of 20-30 μm is mixed with a sufficient amount of epoxy emulsion and placed in a square reaction dish. A fixed magnetic field of 1-2 T is applied to one set of opposite side walls of the square reaction dish, and stirring is performed by reciprocating stirring along the other set of opposite side walls. The reaction is carried out at a constant temperature of 35±1° C. for 2-3 hours. During this time, 1% sodium lignin sulfonate can be added to adjust the diameter to 70-90 μm to obtain a first reaction solution. The first reaction solution is then washed with deionized water and filtered to dryness. The microcapsule base powder is coated with an inner shell layer of 10±2 μm to obtain a rod-like microcapsule base powder. S1-3. Mix the microcapsule base powder with a sufficient amount of epoxy emulsion and place it in a circular reaction dish. Apply a rotating magnetic field of 1 to 2 T at 30 to 60 rpm to the side wall of the circular reaction dish, stir thoroughly, and react at a constant temperature of 35±1°C for 2 to 3 hours. During this period, 1% sodium lignin sulfonate can be added to adjust the particle size to 140 to 170 μm to obtain a second reaction solution. Subsequently, the second reaction solution is washed with deionized water and filtered to dry. The microcapsule base powder is coated with a shell layer of 10±2 μm to obtain spherical composite microcapsules.

3. The composite epoxy resin material according to claim 1, wherein: The epoxy resin is any one of bisphenol A epoxy resin, bisphenol F epoxy resin and glycidylamine epoxy resin.

4. A composite epoxy resin material according to claim 1, characterized in that: The crosslinking agent is polyetheramine D2000.

5. The composite epoxy resin material according to claim 1, wherein: The accelerator is any one of tetrabutylammonium bromide, benzyldimethylamine, and 2-ethyl-4-methylimidazole.

6. The composite epoxy resin material according to claim 1, wherein: The doping amount of magnetic powder in the magnetic-doped epoxy resin is 30-50 wt %, the particle size of the magnetic powder is 5-10 μm, and the epoxy resin in the magnetic-doped epoxy resin is any one of bisphenol A epoxy resin and bisphenol F epoxy resin.

7. The composite epoxy resin material according to claim 1, wherein: The piezoelectric nanoparticles are ZnO@BaTiO3, and the cross-linking agent is polyetheramine D2000.

8. The composite epoxy resin material according to claim 7, wherein: The piezoelectric nanoparticles are coated, specifically: The piezoelectric nanoparticles are placed in a honeycomb mill, and silane coupling agent accounting for 5-10% of the mass of the piezoelectric nanoparticles is sprayed intermittently. The temperature is controlled at 60-70° C. The intermittent spraying is spraying for 2 seconds and stopping for 3-5 seconds.

9. A method for preparing a composite epoxy resin material, characterized in that: The composite epoxy resin material according to any one of claims 1 to 7 comprises the following steps: S1, prepare composite microcapsules for standby use; S2, stirring the epoxy resin and the crosslinking agent at 50-60° C. and a vacuum degree of -0.08 MPa for 1-2 hours to obtain a resin base liquid; S3. Alternately add piezoelectric nanoparticles and composite microcapsules to the resin base liquid, with the single addition amount accounting for 5-10% of the total amount of each. Stir at 1400-1800 rpm for 30-60 minutes and control the temperature below 38° C. to obtain a composite epoxy resin material.

10. The method for preparing a composite epoxy resin material according to claim 9, wherein: In S2 , a variable magnetic field of 0.4 to 0.8 T is added during stirring, and the variable magnetic field is reciprocated between 0.4 and 0.8 T at an enhancement / decay rate of ±0.1 to 0.2 T / min.

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