Composite electric wire and manufacturing method thereof

Abstract

The invention relates to the technical field of electric wire manufacturing, and discloses a composite electric wire and a manufacturing method thereof.The electric wire is of a multi-layer structure comprising an inner layer, a middle layer and an outer layer, and the inner layer is made of modified polyimide; the material of the middle layer is nano composite polyurethane, and the nano composite polyurethane contains nano materials such as carbon nano tubes, graphene, nano silicon dioxide and nano aluminum oxide; the outer layer is made of a fluorinated polymer; the nano material is subjected to surface modification through a silane coupling agent and is uniformly distributed in the polyurethane matrix through a high-frequency ultrasonic dispersion technology; according to the multilayer structure, the interface bonding force is enhanced through plasma treatment or chemical treatment, and the bonding strength between the layers is further improved through an epoxy resin adhesive; the composite electric wire is prepared through a multi-layer co-extrusion process, the high temperature resistance, the pressure resistance, the mechanical strength and the environmental tolerance of the electric wire can be remarkably improved, and the composite electric wire is suitable for application scenes with high requirements for electrical insulation performance in a complex environment.

Description

Technical Field

[0001] The invention relates to the technical field of electric wire manufacturing, in particular to a composite electric wire and a manufacturing method thereof. Background Art

[0002] In modern high-performance electrical equipment and engineering applications, the insulation performance, mechanical strength and environmental tolerance of wires are particularly critical. Especially in the fields of aerospace, smart grid, rail transit, etc., wires need to withstand the challenges of high temperature, high pressure and complex mechanical stress, and must also have corrosion resistance, aging resistance and excellent electrical insulation performance. Traditional wire insulation materials, such as polyvinyl chloride (PVC), polyethylene (PE) and rubber, although they perform well under normal use environments, often fail under extreme conditions due to high-temperature pyrolysis, decreased mechanical strength and degradation of electrical properties, limiting their application in high-demand environments.

[0003] In recent years, with the development of nanotechnology, nanocomposites have gradually become an important direction for improving the performance of wires due to their excellent performance in mechanical properties, electrical properties, heat resistance, etc. By combining nanomaterials (such as carbon nanotubes, graphene, nano-SiO2, etc.) with polymer matrices, the mechanical strength, thermal conductivity and electrical insulation of the materials can be significantly improved. However, the dispersibility and interfacial bonding of nanomaterials in polymer matrices are still the difficulties that need to be solved in the preparation of nanocomposites.

[0004] In addition, single-layer insulation materials often have difficulty meeting all performance requirements, so multi-layer gradient structure design becomes an effective solution. By selecting a combination of materials with different functions, the inner layer material can provide excellent electrical insulation, the middle layer material provides good mechanical strength and elasticity, and the outer layer material ensures excellent environmental resistance. However, in the multi-layer structure design, the interface adhesion between the layers of material is poor, which can easily cause interlayer separation or delamination, affecting the overall performance of the wire. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a composite wire and a method for manufacturing the same, which solves the problems of performance degradation of existing wires under high temperature, high pressure and complex environments, as well as uneven dispersion of nanomaterials and insufficient interlayer adhesion, and significantly improves the high temperature resistance, pressure resistance, mechanical strength and environmental tolerance of the wires.

[0006] To achieve the above objectives, the present invention is implemented by the following technical solutions: A composite wire includes a multi-layer structure, including an inner layer, an intermediate layer and an outer layer from the inside to the outside, wherein:

[0007] The inner layer material is modified polyimide, with a mass percentage of 20-30%;

[0008] The middle layer material is nano-composite polyurethane, with a mass percentage of 30-40%;

[0009] The outer layer material is a fluorinated polymer with a mass percentage of 30-40%.

[0010] Preferably, the nanocomposite polyurethane in the intermediate layer material comprises the following nanomaterials:

[0011] Carbon nanotubes, 1-5% by mass;

[0012] Graphene, 1-5% by mass;

[0013] Nano silicon dioxide, mass percentage is 1-10%;

[0014] Nano-alumina, mass percentage is 1-10%.

[0015] Preferably, the nanomaterial is modified by a silane coupling agent, wherein the silane coupling agent is γ-aminopropyltriethoxysilane, and the modification method comprises the following steps:

[0016] a) dispersing the nanomaterial in an ethanol solution, wherein the weight ratio of the nanomaterial to the ethanol is 1:10-1:20;

[0017] b) adding silane coupling agent APTES and stirring for 30-60 minutes;

[0018] c) Dry at 60-80°C for 4-6 hours.

[0019] Preferably, the inner layer material, the nano-composite polyurethane middle layer material and the fluorinated polymer outer layer material are bonded together by an epoxy resin adhesive.

[0020] Preferably, the adhesion between the layers of the multilayer structure is enhanced by interface treatment, and the interface treatment method includes:

[0021] 1) Plasma treatment;

[0022] 2) Chemical treatment: the chemical treatment agent used is triethanolamine.

[0023] The present invention also provides a method for manufacturing the composite electric wire, comprising the following steps:

[0024] S1. Surface modification of nanomaterials;

[0025] S2, high-frequency ultrasonic dispersion of nanomaterials;

[0026] S3, preparing nano composite polyurethane intermediate layer material;

[0027] S4. Multi-layer co-extrusion process forms a multi-layer structure.

[0028] Preferably, in step S1, the surface modification of the nanomaterial specifically comprises stirring the nanomaterial in a silane coupling agent solution for 30-60 minutes, and then drying at 60-80° C. for 4-6 hours.

[0029] Preferably, in step S2, the surface-modified nanomaterial is added to the matrix polymer solution, the weight ratio of the matrix polymer to the solvent is 1:5-1:10, and the ultrasonic time is 30-60 minutes.

[0030] Preferably, in step S3, uniform mixing and extrusion are performed by a twin-screw extruder at 160-200° C., a screw speed of 50-150 rpm, and an extrusion pressure of 5-10 MPa to form a nano-composite polyurethane intermediate layer material.

[0031] Preferably, the step S4 specifically includes:

[0032] The extrusion temperature of the inner layer material is 160-200°C, and the extrusion speed is 0.5-1.5m / min;

[0033] The extrusion temperature of the middle layer material is 140-180°C, and the extrusion speed is 0.5-1.5m / min;

[0034] The extrusion temperature of the outer layer material is 180-220°C, and the extrusion speed is 0.5-1.5 m / min.

[0035] The present invention provides a composite electric wire and a manufacturing method thereof. The composite electric wire has the following beneficial effects:

[0036] 1. The present invention uses modified polyimide as the inner layer material, which has excellent high temperature resistance and can effectively resist material aging in high temperature environments, ensuring the stability and service life of the wire under extreme high temperatures. This enables the wire to perform well in high temperature scenarios such as aerospace.

[0037] 2. The intermediate layer of the present invention adopts nano-composite polyurethane material, combined with nano-materials such as carbon nanotubes and graphene, which greatly enhances the tensile strength, toughness and wear resistance of the material. This ensures that the wire can still maintain good structural stability when subjected to mechanical stress, bending and wear, and is suitable for occasions with high mechanical strength requirements.

[0038] 3. The polyimide in the inner layer and the nanocomposite polyurethane material in the middle layer of the present invention have excellent dielectric properties and can provide high electrical insulation strength. In particular, the introduction of nanomaterials optimizes the microstructure of the wire, so that it can still maintain a stable insulation effect under high voltage conditions and reduce the risk of electrical leakage.

[0039] 4. The outer layer of the present invention adopts fluorinated polymer material, which has excellent resistance to chemical corrosion, UV rays and aging, ensuring that the wires still have excellent environmental tolerance when exposed to harsh environmental conditions (such as sunlight, chemical corrosive substances, etc.), and can extend the service life of the wires in outdoor application scenarios.

[0040] 5. The present invention processes the interfaces of each layer by plasma treatment or chemical treatment, and adds epoxy resin adhesive to improve the bonding strength between the multi-layer materials and avoid the problem of inter-layer delamination. This ensures the stability of the overall structure of the wire, especially in complex use environments, and will not cause structural failure due to thermal expansion and contraction or mechanical stress. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] Example 1: Composite wire used in high temperature and high pressure applications

[0043] Material ratio:

[0044] Inner layer material: modified polyimide (PI), mass percentage is 25%;

[0045] Middle layer material: nanocomposite polyurethane (PU), mass percentage is 35%;

[0046] Carbon nanotubes: 2%;

[0047] Graphene: 2%;

[0048] Nano silicon dioxide: 5%;

[0049] Nano-alumina: 5%;

[0050] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 40%.

[0051] Process steps:

[0052] 1. Surface modification of nanomaterials:

[0053] Nanomaterials (carbon nanotubes, graphene, nano-silica, and nano-alumina) were mixed with ethanol at a weight ratio of 1:15, and 0.5% APTES was added and stirred for 40 minutes;

[0054] Dry at 70 °C for 5 hours to ensure full modification.

[0055] 2. High-frequency ultrasonic dispersion of nanomaterials:

[0056] The modified nanomaterials were added to the polyurethane solution with a weight ratio of matrix to solvent of 1:8;

[0057] The ultrasound frequency was 30 kHz and the ultrasound time was 45 minutes.

[0058] 3. Preparation of nanocomposite polyurethane intermediate layer material:

[0059] A twin-screw extruder was used for extrusion at 170°C, a screw speed of 120 rpm, and an extrusion pressure of 8 MPa.

[0060] 4. Multi-layer co-extrusion process:

[0061] The extrusion temperature of the inner layer PI was 180°C and the speed was 1.0 m / min;

[0062] The extrusion temperature of the middle layer PU is 160°C and the speed is 1.0m / min;

[0063] The extrusion temperature of the outer layer PVDF was 200°C and the speed was 1.0 m / min.

[0064] Example 2: Composite wire for use in wear-resistant and high mechanical strength applications

[0065] Material ratio:

[0066] Inner layer material: modified polyimide (PI), mass percentage is 20%;

[0067] Middle layer material: nanocomposite polyurethane (PU), mass percentage is 40%;

[0068] Carbon nanotubes: 3%;

[0069] Graphene: 3%;

[0070] Nano silicon dioxide: 7%;

[0071] Nano-alumina: 7%;

[0072] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 30%.

[0073] Process steps:

[0074] 1. Surface modification of nanomaterials:

[0075] The nanomaterials were mixed with ethanol at a weight ratio of 1:10, and 0.8% APTES was added and stirred for 50 min;

[0076] Dry at 75°C for 4.5 hours.

[0077] 2. High-frequency ultrasonic dispersion of nanomaterials:

[0078] The surface-modified nanomaterials were added into the matrix solution, the weight ratio of the matrix to the solvent was 1:7, the ultrasonic frequency was 40 kHz, and the time was 50 minutes.

[0079] Preparation of nanocomposite polyurethane intermediate layer material:

[0080] The temperature of the twin-screw extruder was controlled at 160°C, the screw speed was 100 rpm, and the extrusion pressure was 7 MPa.

[0081] 3. Multi-layer co-extrusion process:

[0082] The extrusion temperature of the inner layer PI was 190°C and the speed was 1.2 m / min;

[0083] The extrusion temperature of the middle layer PU is 150°C and the speed is 1.2m / min;

[0084] The extrusion temperature of the outer layer PVDF is 210°C and the speed is 1.2 m / min.

[0085] Example 3: Composite wire with excellent corrosion resistance

[0086] Material ratio:

[0087] Inner layer material: modified polyimide (PI), mass percentage is 30%;

[0088] Middle layer material: nanocomposite polyurethane (PU), mass percentage is 30%;

[0089] Carbon nanotubes: 1.5%;

[0090] Graphene: 1.5%;

[0091] Nano silicon dioxide: 4%;

[0092] Nano-alumina: 4%;

[0093] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 40%.

[0094] Process steps:

[0095] 1. Surface modification of nanomaterials:

[0096] The nanomaterials were mixed with ethanol at a weight ratio of 1:20, and 0.6% APTES was added and stirred for 60 min;

[0097] Dry at 80°C for 4 hours.

[0098] 2. High-frequency ultrasonic dispersion of nanomaterials:

[0099] The nanomaterials were added into the polyurethane solution, the weight ratio of the matrix to the solvent was 1:6, the ultrasonic frequency was 35 kHz, and the ultrasonic time was 40 minutes.

[0100] 3. Preparation of nanocomposite polyurethane intermediate layer material:

[0101] A twin-screw extruder was used with the temperature set at 165°C, the screw speed at 80 rpm, and the extrusion pressure at 6 MPa.

[0102] 4. Multi-layer co-extrusion process:

[0103] The extrusion temperature of the inner layer PI was 170°C and the speed was 0.8 m / min;

[0104] The extrusion temperature of the middle layer PU is 140°C and the speed is 0.8m / min;

[0105] The extrusion temperature of the outer layer PVDF is 190°C and the speed is 0.8 m / min.

[0106] Example 4: Lightweight composite wire for aerospace applications

[0107] Material ratio:

[0108] Inner layer material: modified polyimide (PI), mass percentage is 22%;

[0109] Middle layer material: nanocomposite polyurethane (PU), mass percentage is 38%;

[0110] Carbon nanotubes: 1.5%;

[0111] Graphene: 1.5%;

[0112] Nano silicon dioxide: 3%;

[0113] Nano-alumina: 3%;

[0114] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 40%.

[0115] Process steps:

[0116] 1. Surface modification of nanomaterials:

[0117] The nanomaterials were mixed with ethanol at a weight ratio of 1:15, and 0.7% APTES was added and stirred for 35 min;

[0118] Dry at 65°C for 5 hours.

[0119] 2. High-frequency ultrasonic dispersion of nanomaterials:

[0120] The nanomaterials were added into the polyurethane solution, the weight ratio of the matrix to the solvent was 1:5, the ultrasonic frequency was 30 kHz, and the ultrasonic time was 50 minutes.

[0121] 3. Preparation of nanocomposite polyurethane intermediate layer material:

[0122] A twin-screw extruder was used with the temperature set at 170°C, the screw speed at 90 rpm, and the extrusion pressure at 9 MPa.

[0123] 4. Multi-layer co-extrusion process:

[0124] The extrusion temperature of the inner layer PI was 175°C and the speed was 1.3 m / min;

[0125] The extrusion temperature of the middle layer PU is 155°C and the speed is 1.3m / min;

[0126] The extrusion temperature of the outer layer PVDF was 205°C and the speed was 1.3 m / min.

[0127] Example 5: Low-cost, universal composite wire

[0128] Material ratio:

[0129] Inner layer material: modified polyimide (PI), mass percentage is 20%;

[0130] Middle layer material: nanocomposite polyurethane (PU), mass percentage is 40%;

[0131] Carbon nanotubes: 2.5%;

[0132] Graphene: 2.5%;

[0133] Nano silicon dioxide: 6%;

[0134] Nano-alumina: 6%;

[0135] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 40%.

[0136] Process steps:

[0137] 1. Surface modification of nanomaterials:

[0138] The nanomaterials were mixed with ethanol in a weight ratio of 1:12, and 0.5% APTES was added and stirred for 60 min;

[0139] Dry at 70°C for 4.5 hours.

[0140] 2. High-frequency ultrasonic dispersion of nanomaterials:

[0141] The nanomaterials were added into the PU solution, the weight ratio of matrix to solvent was 1:7, the ultrasonic frequency was 25 kHz, and the ultrasonic time was 40 min.

[0142] 3. Preparation of nanocomposite polyurethane intermediate layer material:

[0143] A twin-screw extruder was used for extrusion at 160°C, a screw speed of 70 rpm, and an extrusion pressure of 6 MPa.

[0144] 4. Multi-layer co-extrusion process:

[0145] The extrusion temperature of the inner layer PI was 165°C and the speed was 1.0 m / min;

[0146] The extrusion temperature of the middle layer PU is 145°C and the speed is 1.0m / min;

[0147] The extrusion temperature of the outer layer PVDF was 195°C and the speed was 1.0 m / min.

[0148] Comparative experiment 1: Electrical performance comparison experiment

[0149] Purpose: To verify whether the composite wire of the present invention is superior to the traditional formula materials in terms of electrical properties such as dielectric constant, breakdown voltage and electrical insulation strength.

[0150] Experimental content:

[0151] Test items: dielectric constant, breakdown voltage, electrical insulation strength

[0152] Material preparation of experimental group and comparative example:

[0153] Experimental group (using the nanocomposite material and multilayer structure of the present invention):

[0154] Inner layer material: modified polyimide (PI), mass percentage is 25%.

[0155] Middle layer material: nano-composite polyurethane (PU), with a mass percentage of 35%.

[0156] Nanomaterial ratio:

[0157] Carbon nanotubes: 2%;

[0158] Graphene: 2%;

[0159] Nano silicon dioxide: 5%;

[0160] Nano-alumina: 5%.

[0161] Nanomaterial surface modification: Modification is carried out by using APTES silane coupling agent. The specific method is as follows:

[0162] The nanomaterials were mixed with ethanol at a weight ratio of 1:15, and 0.5% APTES was added and stirred for 40 min;

[0163] Dry at 70°C for 5 hours;

[0164] Nanomaterial dispersion: The modified nanomaterials were added into the polyurethane matrix and dispersed using high-frequency ultrasound (30 kHz, 45 min);

[0165] Preparation of the middle layer material: The twin-screw extruder was extruded at 170°C, the screw speed was 120 rpm, and the extrusion pressure was 8 MPa.

[0166] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 40%.

[0167] Comparative Example 1 (traditional materials, polymer without adding nanomaterials):

[0168] Inner layer material: polyimide (PI), mass percentage is 30%.

[0169] Middle layer material: polyurethane (PU), mass percentage is 35%, no nano material is added.

[0170] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0171] Comparative Example 2 (conventional composite material using micron-sized filler material):

[0172] Inner layer material: polyimide (PI), mass percentage is 30%.

[0173] Middle layer material: micron-filled polyurethane (PU), with a mass percentage of 35%.

[0174] Filling material ratio:

[0175] Micronized silica: 8%;

[0176] Micron Alumina: 8%.

[0177] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0178] Experimental process:

[0179] 1. Sample preparation: After preparing different samples according to the above formula, extrude the composite wire samples according to the multi-layer co-extrusion process and cut them into standard sizes for testing.

[0180] 2. Test equipment:

[0181] Dielectric constant test: Use LCR meter to measure dielectric constant at different frequencies;

[0182] Breakdown voltage test: Use a high voltage breakdown tester to gradually increase the voltage until the dielectric breaks down;

[0183] Electrical insulation strength test: Use a dielectric strength tester to measure the insulation resistance value of a material under high voltage.

[0184] The experimental data are shown in the following table:

[0185]

[0186]

[0187] Data Analysis and Conclusion:

[0188] Dielectric Constant:

[0189] From the experimental data, it can be seen that the dielectric constant of the experimental group is significantly higher than that of Comparative Examples 1 and 2 at 1kHz and 10kHz. This shows that after adding highly conductive nanomaterials such as carbon nanotubes and graphene, the dielectric polarization ability of the material is enhanced, resulting in an increase in the dielectric constant. This is very important for insulating materials that require a high dielectric constant, such as when used in electrical equipment, it can effectively reduce power loss.

[0190] Breakdown voltage:

[0191] The breakdown voltage of the experimental group reached 40kV / mm, which is much higher than 30kV / mm of comparative example 1 and 33kV / mm of comparative example 2. The breakdown voltage is an important indicator to measure the ability of a material to withstand high voltage. Nanomaterials can form an efficient energy barrier to hinder the propagation of electric fields in the material, thereby increasing the breakdown voltage.

[0192] Electrical insulation strength:

[0193] The electrical insulation strength of the experimental group is 1200MΩ, which is significantly higher than 800MΩ of Comparative Example 1 and 950MΩ of Comparative Example 2. This shows that the nanocomposite material performs better in terms of insulation resistance, especially in a high-voltage environment, where the uniform distribution of nanomaterials can effectively reduce the risk of electrical leakage and ensure the stability of insulation performance.

[0194] The following conclusions can be drawn from the above experimental data:

[0195] Improved dielectric properties: Nanocomposites, due to their high conductivity and high specific surface area, are able to maintain a higher dielectric constant at both low and high frequencies, significantly better than traditional materials. Especially in power equipment or high-frequency electrical applications, this performance improvement can effectively reduce dielectric losses.

[0196] Significantly improved breakdown voltage: The nanocomposites in the experimental group showed a higher breakdown voltage, proving that nanomaterials (such as nano-silicon dioxide and nano-aluminum oxide) can significantly improve the high-voltage resistance of materials. This means that the service life and safety of wires are enhanced when used in high-voltage electrical equipment.

[0197] Enhanced insulation strength: The electrical insulation performance of nanocomposites is superior to that of traditional materials. This is because the uniform dispersion of nanomaterials can effectively suppress current leakage and improve insulation reliability.

[0198] In summary, the nanocomposite material of the present invention has significant advantages in electrical properties, especially in terms of high dielectric constant, breakdown voltage and electrical insulation strength, which are far superior to traditional materials.

[0199] Comparative experiment 2: Comparative experiment of thermal stability and high temperature resistance

[0200] Purpose: To verify the superiority of the composite wire in the present invention in terms of thermal stability and high temperature resistance, and to evaluate its service life and stability in a high temperature environment.

[0201] Experimental content:

[0202] Test items:

[0203] Thermogravimetric analysis (TGA): test the thermal degradation temperature (Thermal Decomposition Temperature, Td) and initial thermal weight loss temperature of the test material.

[0204] Coefficient of Thermal Expansion (CTE): Tests the expansion behavior of a material after being heated, reflecting the thermal stability of the material.

[0205] Heat Deformation Temperature (HDT): Measures the temperature at which a material undergoes significant deformation under a certain load, reflecting the material's high temperature resistance.

[0206] Material preparation of experimental group and comparative example:

[0207] Experimental group (using the nanocomposite material and multilayer structure of the present invention):

[0208] Inner layer material: modified polyimide (PI), mass percentage is 25%.

[0209] Middle layer material: nano-composite polyurethane (PU), with a mass percentage of 35%.

[0210] Nanomaterial ratio:

[0211] Carbon nanotubes: 2%;

[0212] Graphene: 2%;

[0213] Nano silicon dioxide: 5%;

[0214] Nano-alumina: 5%.

[0215] Nanomaterial surface modification: Modification by APTES silane coupling agent, the specific steps are as follows:

[0216] The nanomaterials were mixed with ethanol at a weight ratio of 1:15, and 0.5% APTES was added and stirred for 40 min;

[0217] Dry at 70°C for 5 hours;

[0218] Nanomaterial dispersion: The modified nanomaterials were dispersed into the polyurethane matrix by high-frequency ultrasound (30 kHz, 45 min);

[0219] Preparation of the middle layer material: Extrusion was performed by a twin-screw extruder at 170° C., a screw speed of 120 rpm, and an extrusion pressure of 8 MPa.

[0220] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 40%.

[0221] Comparative Example 3 (no nanomaterials, only matrix materials):

[0222] Inner layer material: polyimide (PI), mass percentage is 30%.

[0223] Middle layer material: polyurethane (PU), with a mass percentage of 35%, and does not contain nano materials.

[0224] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0225] Comparative Example 4 (using thermoplastic elastomer (TPE) as the middle layer):

[0226] Inner layer material: polyimide (PI), mass percentage is 30%.

[0227] Middle layer material: thermoplastic elastomer (TPE), mass percentage is 35%.

[0228] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0229] Comparative Example 5 (conventional composite material using micron-sized filler material):

[0230] Inner layer material: polyimide (PI), mass percentage is 30%.

[0231] Middle layer material: polyurethane (PU), mass percentage is 35%.

[0232] Filling material ratio:

[0233] Micronized silicon dioxide: 10%;

[0234] Micron Alumina: 5%.

[0235] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0236] 1. Experimental process:

[0237] Sample preparation: The experimental group and comparative sample were prepared according to the above formula, formed by multi-layer co-extrusion process, and cut into standard size for thermal performance testing.

[0238] 2. Test equipment:

[0239] Thermal gravimetric analysis (TGA): Heating in a nitrogen atmosphere, using a thermogravimetric analyzer to test the thermal weight loss of the material, gradually raising the temperature to 800°C, and recording the degradation temperature.

[0240] Coefficient of Thermal Expansion (CTE): The coefficient of linear expansion of a material is measured using a Thermomechanical Analyzer (TMA).

[0241] Heat Deformation Temperature (HDT): Using a heat deformation tester, the temperature at which the material undergoes significant deformation under a specified load is measured by applying a constant load and then increasing the temperature.

[0242] The experimental results are shown in the following table:

[0243]

[0244]

[0245] Data Analysis and Conclusion:

[0246] Thermogravimetric analysis (TGA):

[0247] Initial thermal weight loss temperature: The initial thermal weight loss temperature of the experimental group is 450°C, which is significantly higher than 380°C of Comparative Example 3 and 410°C of Comparative Example 5, especially the TPE middle layer of Comparative Example 4, whose initial thermal weight loss temperature is only 300°C. This shows that the experimental group materials have stronger thermal stability at high temperatures, and the nanomaterials can form a thermal barrier to delay the degradation of the materials.

[0248] 5% thermal weight loss temperature (Td5): The 5% thermal weight loss temperature of the experimental group is 525°C, which is higher than that of Comparative Example 3 (440°C), Comparative Example 4 (350°C) and Comparative Example 5 (480°C). Nanomaterials can not only improve thermal stability, but also their high surface energy and good dispersibility can improve the heat resistance of the matrix material. In particular, compared with the TPE intermediate layer, the polyurethane matrix combined with nanomaterials has better heat tolerance.

[0249] Coefficient of Thermal Expansion (CTE):

[0250] The thermal expansion coefficient of the experimental group is 55×10 -6 / ℃, much lower than that of comparative example 3 (90×10 -6 / ℃) and Comparative Example 4 (120×10 -6 / ℃), which is also lower than 80×10 -6 / ℃. This shows that nanomaterials can significantly reduce the thermal expansion behavior of materials by enhancing their mechanical properties and thermal stability, thus ensuring their dimensional stability at high temperatures.

[0251] Heat Deflection Temperature (HDT):

[0252] The heat deformation temperature of the experimental group is 210°C, which is significantly higher than 160°C of Comparative Example 3, 135°C of Comparative Example 4, and 170°C of Comparative Example 5. Nanomaterials enhance the mechanical strength and heat resistance of materials, making them more resistant to deformation under high temperature loads, especially in high temperature environments such as aerospace, which can effectively extend the service life of materials.

[0253] Through the analysis of the above experimental data, the following conclusions can be drawn:

[0254] Significantly improved thermal stability: The nanocomposite material of the present invention exhibits higher thermal stability in terms of thermal weight loss initial temperature and 5% thermal weight loss temperature (Td5). This is because the nanomaterials are evenly dispersed in the matrix to form a more effective thermal barrier, delaying the degradation and decomposition process of the material, and significantly improving the thermal tolerance of the material.

[0255] Reduced thermal expansion coefficient: The thermal expansion coefficient of the experimental group is significantly lower than that of the control group. This shows that nanomaterials, especially carbon nanotubes and graphene, can enhance the structural strength of materials and reduce the volume change of materials at high temperatures. This plays a vital role in the dimensional stability of wires in high-temperature applications.

[0256] Improved heat deformation temperature: The nanocomposite material of the present invention exhibits a higher heat deformation temperature, proving that it has a stronger ability to deform under high temperature loads. This is attributed to the nanomaterial improving the mechanical properties and heat resistance of the material, making the material have better resistance to deformation under high temperature environments.

[0257] In summary, the nanocomposite material of the present invention exhibits significant advantages in thermal stability and high temperature resistance, especially in that the service life and stability of the material under high temperature conditions are greatly improved.

[0258] Comparative experiment 3: Mechanical properties comparison experiment

[0259] Objective: To verify the improvement effect of the nanocomposite material of the present invention in terms of mechanical properties (such as tensile strength, elongation at break, wear resistance, and impact resistance) and to evaluate its applicability in high-strength, wear-resistant applications.

[0260] Experimental content:

[0261] Test items:

[0262] Tensile Strength: A measure of the maximum stress in a material under a tensile load.

[0263] Elongation at break: The elongation of a material when stretched to break.

[0264] Wear resistance: Evaluates the wear behavior of a material under friction.

[0265] Impact resistance: Tests the material's toughness under impact load.

[0266] Material preparation of experimental group and comparative example:

[0267] Experimental group (the present invention: nanocomposite materials and multilayer structures):

[0268] Inner layer material: modified polyimide (PI), mass percentage is 25%.

[0269] Middle layer material: nano-composite polyurethane (PU), with a mass percentage of 35%.

[0270] Nanomaterial ratio:

[0271] Carbon nanotubes: 2%;

[0272] Graphene: 2%;

[0273] Nano silicon dioxide: 5%;

[0274] Nano-alumina: 5%.

[0275] Nanomaterial modification: Modification by APTES silane coupling agent, the specific steps are:

[0276] The nanomaterials were mixed with ethanol at a weight ratio of 1:15, and 0.5% APTES was added and stirred for 40 min;

[0277] Dry at 70°C for 5 hours;

[0278] Nanomaterial dispersion: Dispersed in the polyurethane matrix by high-frequency ultrasound (30 kHz, 45 minutes).

[0279] Preparation of the middle layer material: through a twin-screw extruder, the temperature is 170°C, the screw speed is 120rpm, and the extrusion pressure is 8MPa.

[0280] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 40%.

[0281] Comparative Example 6 (using conventional materials of unmodified polyurethane and polyimide):

[0282] Inner layer material: unmodified polyimide (PI), mass percentage is 30%.

[0283] Middle layer material: unmodified polyurethane (PU), with a mass percentage of 35%, and does not contain any nanomaterials.

[0284] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0285] Comparative Example 7 (using traditional rubber-based composite material):

[0286] Inner layer material: polyimide (PI), mass percentage is 30%.

[0287] Middle layer material: natural rubber (NR), mass percentage is 35%.

[0288] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0289] Comparative Example 8 (conventional composite material reinforced with metal fibers):

[0290] Inner layer material: polyimide (PI), mass percentage is 30%.

[0291] Middle layer material: metal fiber reinforced polyurethane (PU), with a mass percentage of 35%, of which the mass percentage of metal fiber is 10%.

[0292] Outer layer material: polyvinylidene fluoride (PVDF), mass percentage is 35%.

[0293] Experimental process:

[0294] Sample preparation: Different samples were prepared according to the above formula, extruded into composite wire samples through a multi-layer co-extrusion process, and cut into standard sizes for the following mechanical property tests.

[0295] Test equipment:

[0296] Tensile strength and elongation at break test: Use a universal material testing machine to stretch the sample at a constant speed and record the maximum stress (tensile strength) and elongation at break.

[0297] Wear resistance test: Use a wear tester to perform friction tests on samples at constant pressure and speed, and record the amount of wear.

[0298] Impact resistance test: Use a pendulum impact tester to test the impact strength and fracture toughness of the sample.

[0299] The experimental results are shown in the following table:

[0300]

[0301] Data Analysis and Conclusion:

[0302] Tensile Strength:

[0303] The tensile strength of the experimental group is 85MPa, which is significantly higher than Comparative Example 6 (55MPa) and Comparative Example 7 (45MPa), and second only to Comparative Example 8 (75MPa). Compared with unmodified polyurethane and traditional rubber-based materials, the introduction of nanomaterials (carbon nanotubes, graphene, etc.) greatly enhances the tensile strength of the material. Although metal fiber reinforced materials also show higher strength, nanocomposites are more advantageous because they have better toughness and wear resistance while maintaining high tensile strength.

[0304] Elongation at break:

[0305] The elongation at break of the experimental group is 180%, which is much higher than that of Comparative Example 6 (120%) and Comparative Example 8 (80%), but lower than that of Comparative Example 7 (400%). This shows that the nanocomposite material has a high strength while maintaining a certain toughness. Although the rubber-based material has an extremely high elongation, its tensile strength is low and it is difficult to meet the needs of high-strength applications.

[0306] Abrasion resistance:

[0307] The wear resistance of the experimental group showed excellent results, with only 10 mg of friction loss per 1000 times, which was significantly lower than that of Comparative Example 6 (35 mg) and Comparative Example 7 (25 mg). Although the metal fiber reinforced material showed good wear resistance (15 mg), the nanocomposite material of the experimental group showed more balanced performance in strength and wear resistance, which was suitable for applications in high mechanical stress and wear environments.

[0308] Impact resistance:

[0309] The impact resistance of the experimental group is 120kJ / m 2 , higher than comparative example 6 (80 kJ / m 2 ) and Comparative Example 8 (90 kJ / m 2 ), but lower than the rubber-based composite material of Comparative Example 7 (180 kJ / m 2 ). Although rubber-based materials have outstanding performance in impact resistance, their wear resistance and strength are poor, which limits their application in high-load environments. The impact resistance, strength and wear resistance of the experimental group nanocomposites are well balanced and suitable for a variety of complex mechanical environments.

[0310] Through the analysis of experimental data, the following conclusions can be drawn:

[0311] Significantly improved mechanical strength: The nanocomposite material of the present invention exhibits excellent tensile strength, which is much higher than that of conventional unmodified polyurethane and rubber-based materials, and close to the level of metal fiber reinforced materials. Carbon nanotubes and graphene, as high-strength nano-reinforcers, significantly improve the tensile strength and mechanical strength of the material, making the material exhibit even better performance under high mechanical loads.

[0312] Greatly improved wear resistance: Nanomaterials (such as nano-silicon dioxide and nano-alumina) can effectively enhance the wear resistance of materials and reduce friction loss. The experimental group showed extremely excellent results in wear resistance, proving that the material is particularly suitable for applications that require long-term friction or wear, such as industrial conveying equipment, wire and cable insulation, etc.

[0313] More balanced comprehensive performance: Although the rubber-based material performs well in impact resistance and elongation at break, its tensile strength and wear resistance are poor, limiting its applicability in high-strength applications. The nanocomposite material in the experimental group shows a good balance in tensile strength, wear resistance and impact resistance, which is suitable for high mechanical load occasions and performs well in wear-resistant applications.

[0314] Advantages compared to metal fiber reinforced materials: Metal fiber reinforced materials perform well in strength and wear resistance, but their toughness is poor, with an elongation at break of only 80%, and they are prone to breakage under high impact loads. The experimental group material has achieved a good balance between toughness and strength, and its impact resistance and ductility are better than metal fiber materials, making it suitable for occasions that require high strength and high toughness.

[0315] In summary, the nanocomposite material of the present invention exhibits significant advantages in mechanical properties, especially in tensile strength, wear resistance and comprehensive toughness.

[0316] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite electric wire, characterized in that: It includes a multi-layer structure, including an inner layer, a middle layer and an outer layer from the inside to the outside, wherein: The inner layer material is modified polyimide, with a mass percentage of 20-30%; The middle layer material is nano-composite polyurethane, with a mass percentage of 30-40%; The outer layer material is a fluorinated polymer with a mass percentage of 30-40%.

2. A composite electric wire according to claim 1, characterized in that: The nanocomposite polyurethane in the intermediate layer material includes the following nanomaterials: Carbon nanotubes, 1-5% by mass; Graphene, 1-5% by mass; Nano silicon dioxide, mass percentage is 1-10%; Nano-alumina, mass percentage is 1-10%.

3. A composite electric wire according to claim 2, characterized in that: The nano material is modified by a silane coupling agent, wherein the silane coupling agent is γ-aminopropyltriethoxysilane, and the modification method comprises the following steps: a) dispersing the nanomaterial in an ethanol solution, wherein the weight ratio of the nanomaterial to the ethanol is 1:10-1:20; b) adding silane coupling agent APTES and stirring for 30-60 minutes; c) Dry at 60-80°C for 4-6 hours.

4. A composite electric wire according to claim 1, characterized in that: The inner layer material, the nano composite polyurethane middle layer material and the fluorinated polymer outer layer material are bonded together by an epoxy resin adhesive.

5. A composite electric wire according to claim 1, characterized in that: The adhesion between the layers of the multilayer structure is enhanced by interface treatment, and the interface treatment method includes: 1) Plasma treatment; 2) Chemical treatment: the chemical treatment agent used is triethanolamine.

6. A method for manufacturing a composite electric wire according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Surface modification of nanomaterials; S2, high-frequency ultrasonic dispersion of nanomaterials; S3, preparing nano composite polyurethane intermediate layer material; S4. Multi-layer co-extrusion process forms a multi-layer structure.

7. The manufacturing method according to claim 6, characterized in that: In the step S1, the surface modification of the nanomaterial specifically includes stirring the nanomaterial in a silane coupling agent solution for 30-60 minutes, and then drying at 60-80° C. for 4-6 hours.

8. The manufacturing method according to claim 6, characterized in that: In the step S2, the surface-modified nanomaterial is added to the matrix polymer solution, the weight ratio of the matrix polymer to the solvent is 1:5-1:10, and the ultrasonic time is 30-60 minutes.

9. The manufacturing method according to claim 6, characterized in that: In the step S3, uniform mixing and extrusion are performed by a twin-screw extruder at 160-200° C., a screw speed of 50-150 rpm, and an extrusion pressure of 5-10 MPa to form a nano-composite polyurethane intermediate layer material.

10. The manufacturing method according to claim 6, characterized in that: The step S4 specifically includes: The extrusion temperature of the inner layer material is 160-200°C, and the extrusion speed is 0.5-1.5m / min; The extrusion temperature of the middle layer material is 140-180°C, and the extrusion speed is 0.5-1.5m / min; The extrusion temperature of the outer layer material is 180-220°C, and the extrusion speed is 0.5-1.5 m / min.

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