High strength composite material for explosion-proof doors

Abstract

The application discloses a high-strength composite material for an explosion-proof sealing door, which is a composite plate and comprises a plurality of fiber reinforced layers and interlaminar toughening adhesive films arranged in sequence between the fiber reinforced layers; the fiber reinforced layers comprise an outer aramid fiber layer, an intermediate glass fiber layer and an inner ultrahigh molecular weight polyethylene fiber layer; the fiber reinforced layers are all infiltrated by a modified resin matrix, the modified resin matrix is an epoxy-polyurethane interpenetrating network resin system, and the same epoxy-polyurethane is used as a matrix, and different functional mixed fillers are added in sequence to form a resin layer with gradient properties. The application has the beneficial effects that: the application adopts a multi-gradient design of "three-layer gradient fiber + homologous IPN matrix + gradient filler", realizes energy gradient attenuation, and uses an epoxy-polyurethane interpenetrating network (IPN) as a resin matrix, so that the defects of large brittleness of ordinary resin and easy brittle fracture under high strain rate are effectively solved.

Description

Technical Field

[0001] This invention relates to the technical field of airtight doors, specifically to a high-strength composite material for explosion-proof airtight doors. Background Technology

[0002] The fiber-reinforced resin composite panels used in existing explosion-proof airtight doors are typically made of multiple layers of a single type of fiber cloth (such as glass fiber or aramid cloth) impregnated with ordinary bisphenol A type epoxy resin and then hot-pressed and cured. However, this existing technology has the following shortcomings: (1) The single ply structure lacks the energy gradient attenuation design for the "first ablation, then bending, then penetration" of the explosive shock wave, resulting in low overall impact resistance efficiency of the composite material. (2) The resin matrix is ​​not toughened and nano-modified, and exhibits brittle fracture under millisecond-level high strain rate impact, which cannot fully utilize the high strength and toughness characteristics of the fiber. (3) There is a lack of effective toughening interlayers, and the interlayer shear strength is generally lower than 25MPa. When subjected to explosive bending load, delamination is very likely to occur. (4) Insufficient interfacial bonding between fibers and resin matrix makes the fibers prone to pull-out under repeated vibration, causing the composite board to fail prematurely. (5) The glass transition temperature of the resin is too low, making it difficult to resist the instantaneous high temperature accompanying the explosion, which leads to the softening of the matrix and loss of structural load-bearing capacity. Summary of the Invention

[0003] To address the above shortcomings, the present invention provides the following technical solution: A high-strength composite material for explosion-proof airtight doors, the composite material being a composite board comprising several fiber reinforcement layers arranged sequentially from the explosion-facing surface to the back plate, and an interlayer toughening film sandwiched between adjacent fiber reinforcement layers; the fiber reinforcement layers form a gradient structure from the explosion-facing surface to the back plate, specifically including an outer aramid fiber layer, a middle glass fiber layer, and an inner ultra-high molecular weight polyethylene fiber layer; the fiber surfaces of the fiber reinforcement layers are modified with dopamine; each fiber reinforcement layer is impregnated with a modified resin matrix, and the interlayer toughening film and the fiber reinforcement layers are co-cured and molded together by hot pressing; the modified resin matrix is ​​an epoxy-polyurethane interpenetrating network resin system, and each fiber reinforcement layer is based on the same epoxy-polyurethane interpenetrating network as the base matrix, with different functional mixed fillers added sequentially to form a resin layer with gradient properties.

[0004] Furthermore, the modified resin matrix includes a matrix resin IPN and mixed fillers: The matrix resin IPN comprises the following components in parts by weight: 100 parts of bisphenol A type epoxy resin; 17-18 parts of polyurethane prepolymer; 25-30 parts of amine curing agent; Accelerator (DMP-30) 1-2 parts; The mixed filler comprises the following components in parts by weight (based on 100 parts by weight of the matrix resin IPN): Mixed filler 1: 3-7 parts fumed SiO2, 3-5 parts organic montmorillonite (OMMT); Mixed filler 2: 3-6 parts nano-SiO2, 0.1-1 parts graphene oxide; Mixed filler 3: 2-3 parts nano SiO2, 3-5 parts short-cut carbon fiber, and 3-5 parts nano alumina.

[0005] Furthermore, the polyurethane prepolymer is a terminal isocyanate prepolymer based on polypropylene glycol (PPG) and toluene diisocyanate (TDI), with a molar ratio of TDI to PPG of 2:1.

[0006] Furthermore, the nanofillers (including fumed SiO2, nano SiO2, GO, and nano Al2O3) need to undergo ultrasonic dispersion or high-speed shear dispersion pretreatment to ensure uniform dispersion in the resin matrix and avoid agglomeration.

[0007] Furthermore, the bisphenol A type epoxy resin is E-51.

[0008] Furthermore, the dopamine modification agent on the surface of the fiber reinforcement layer is a Tris-HCl buffer solution of dopamine hydrochloride with pH=8.5 and the concentration of dopamine hydrochloride is 1.5-2.0 g / L.

[0009] Furthermore, the T700 grade short-cut carbon fiber.

[0010] Furthermore, the amine curing agent is curing agent 593.

[0011] Furthermore, the interlayer toughening film is a toughened modified epoxy resin film with an areal density of 150–250 g / m³. 2 The curing temperature is 100-150℃.

[0012] A high-strength composite material for explosion-proof airtight doors is prepared through the following process steps: S1. Fiber surface modification: Aramid fiber, glass fiber and ultra-high molecular weight polyethylene fiber are respectively immersed in Tris-HCl buffer solution of dopamine hydrochloride and reacted at 20-30℃ for 20-28 hours. After being taken out, they are washed with deionized water and dried to obtain surface modified fiber. S2. Preparation of modified resin matrix: Weigh out bisphenol A type epoxy resin E-51, polyurethane prepolymer, amine curing agent and accelerator DMP-30 according to the mass parts, and mix them evenly to obtain matrix resin IPN; add the mass parts of mixed filler 1, mixed filler 2 and mixed filler 3 to the matrix resin IPN respectively, and perform ultrasonic dispersion or high-speed shear dispersion treatment to obtain outer layer resin system, middle layer resin system and inner layer resin system respectively; S3. Prepreg preparation: The surface-modified aramid fibers obtained in step S1 are impregnated in the outer resin system to obtain the outer fiber prepreg; the surface-modified glass fibers are impregnated in the middle resin system to obtain the middle fiber prepreg; the surface-modified ultra-high molecular weight polyethylene fibers are impregnated in the inner resin system to obtain the inner fiber prepreg. S4. Lay-up assembly: Following the direction from the blast-facing side to the back panel, lay out the outer layer of fiber prepreg, the interlayer toughening film, the middle layer of fiber prepreg, the interlayer toughening film, and the inner layer of fiber prepreg in sequence to form a composite precast panel.

[0013] The beneficial effects of this invention are as follows: 1. Addressing the destructive characteristics of explosive shock waves—"first ablation, then bending, then penetration"—this invention employs a multi-gradient design of "three-layer gradient fibers + homogeneous IPN matrix + gradient filler," achieving energy gradient attenuation. 2. This invention uses epoxy-polyurethane interpenetrating network (IPN) as the resin matrix, effectively solving the defects of ordinary epoxy resins, such as high brittleness and easy fracture under high strain rates. 3. This invention significantly improves the interfacial bonding force between the fiber and the resin matrix through dopamine modification treatment of the fiber surface. This invention sets an interlayer toughening film between adjacent fiber layers and uses a homologous IPN resin system for one-time hot-press co-curing molding, resulting in chemical cross-linking between the layers. This fundamentally overcomes the defects of traditional composite materials, such as low interlayer shear strength (<25MPa) and easy delamination, ensuring the structural integrity of the composite board under explosive bending loads. 4. This invention uses three layers of gradient fibers and gradient fillers (specifically constructing a gradually changing modulus and damping gradient from the outside to the inside), and the one-time hot-press co-curing of the homologous IPN system enables each gradient layer to be chemically connected without physical discontinuity. This synergy achieves "gradual impedance change" in mechanical properties—that is, when the explosive shock wave propagates between different gradient layers, it avoids the high reflection stress caused by the abrupt change in modulus of traditional laminated composite materials, effectively reducing stress concentration at the interlayer interface, allowing the shock wave to be smoothly transmitted and dissipated layer by layer, rather than being reflected back to the surface at the interlayer boundary, causing premature collapse. Detailed Implementation

[0015] (a) The overall structure of the composite material is as follows: A high-strength composite material for explosion-proof airtight doors is disclosed. The composite material is a composite board comprising several fiber reinforcement layers arranged sequentially from the blast-facing side to the back plate, and an interlayer toughening film sandwiched between adjacent fiber reinforcement layers. The fiber reinforcement layers form a gradient structure from the blast-facing side to the back plate, specifically including an outer aramid fiber layer, a middle glass fiber layer, and an inner ultra-high molecular weight polyethylene fiber layer. The fiber surfaces of the fiber reinforcement layers are treated with dopamine. The interlayer toughening film is a toughened modified epoxy resin film. All fiber reinforcement layers are impregnated with a modified resin matrix, and the interlayer toughening film and fiber reinforcement layers are co-cured and molded together by hot pressing. The modified resin matrix is ​​an epoxy-polyurethane interpenetrating network resin system. Each fiber reinforcement layer is based on the same epoxy-polyurethane interpenetrating network as the base matrix, and different functional mixed fillers are added sequentially to form a resin layer with gradient properties.

[0016] (II) Modified Resin Matrix: IPN resin and mixed fillers: The matrix resin IPN comprises the following components in parts by weight: 100 parts of bisphenol A type epoxy resin (E-51); Polyurethane prepolymer (17-18 parts) is prepared by vacuum dehydrating polypropylene glycol (PPG, number average molecular weight 1000) at 110-120℃ for 1-2 hours, cooling to 50-60℃, adding toluene diisocyanate (TDI), wherein the molar ratio of TDI to PPG is 2:1, and reacting at 80-85℃ for 2-3 hours to obtain isocyanate-terminated polyurethane prepolymer. 25-30 parts of amine curing agent (curing agent 593); Accelerator (DMP-30) 1-2 parts; The mixed filler comprises the following components in parts by weight (based on 100 parts by weight of the matrix resin IPN): Mixed filler 1: 3-7 parts of fumed SiO2 (hydrophobic fumed silica, BET specific surface area 130±20m²) 2 / g, surface-treated with dimethyldichlorosilane), 3-5 parts of organomontmorillonite OMMT (interlayer spacing ≥2.0nm); Mixed filler 2: 3-6 parts of nano-SiO2 (particle size 20-30nm) and 0.1-1 parts of graphene oxide (GO) (sheet size 0.5-5μm, monolayer ratio ≥95%); Mixed filler 3: 2-3 parts of nano SiO2 (particle size 20-30nm), 3-5 parts of T700 grade short-cut carbon fiber (3-6mm, epoxy sizing agent), and 3-5 parts of nano alumina (γ-Al2O3, particle size 20-30nm).

[0017] The interlayer toughening film is a toughened modified epoxy resin film (GXA120) with an areal density of 150–250 g / m³.2 The curing temperature is 100-150℃; The dopamine modification agent on the surface of the fiber reinforcement layer is a Tris-HCl buffer solution of dopamine hydrochloride with pH=8.5 and a dopamine hydrochloride concentration of 1.5-2.0 g / L.

[0018] Among them, aramid fiber, glass fiber, and ultra-high molecular weight polyethylene fiber are all commercially available products, and the outer aramid fiber is made of plain weave fabric with a strength of 200-240 g / m². 2 Specifications: The middle layer of glass fiber is made of plain weave fabric, 400-600 g / m². 2 Specifications: The inner layer of UHMWPE fiber is made of plain weave fabric, 100-200g / m². 2 Specification.

[0019] (III) The process flow for preparing composite materials is as follows: S1. Fiber surface modification: Prepare a Tris-HCl buffer solution with pH=8.5 for later use. Dissolve dopamine hydrochloride in the above Tris-HCl buffer solution (pH=8.5) to prepare a modification solution with a concentration of 1.5-2.0 g / L. Immerse aramid fiber, glass fiber and ultra-high molecular weight polyethylene fiber in the Tris-HCl buffer solution of dopamine hydrochloride respectively, react at 25°C for 24 hours, remove and wash repeatedly with deionized water 3 times, and vacuum dry at 60°C to constant weight to obtain surface modified fiber.

[0020] S2. Preparation of modified resin matrix: Weigh out bisphenol A type epoxy resin E-51, polyurethane prepolymer, curing agent 593 and accelerator DMP-30 according to the mass parts, and mix them evenly by mechanical stirring at 60℃ to obtain matrix resin IPN.

[0021] Different mixed fillers were added to the IPN matrix resin: the outer layer resin system contained corresponding mass parts of fumed SiO2 and organomontmorillonite (OMMT); the middle layer resin system contained corresponding mass parts of nano-SiO2 and graphene oxide; and the inner layer resin system contained corresponding mass parts of nano-SiO2, chopped carbon fibers, and nano-alumina. Each mixed system was ultrasonically dispersed for 30 min (ultrasonic power 400 W, frequency 20 kHz) to ensure uniform dispersion of the fillers in the resin matrix, resulting in the outer, middle, and inner layer resin systems, respectively.

[0022] S3. Prepreg preparation: The surface-modified aramid fibers obtained in step S1 are impregnated in the outer resin system, and excess resin is extruded by roller pressing, with the resin content controlled at 32±2wt%, to obtain the outer fiber prepreg; the surface-modified glass fibers are impregnated in the middle resin system, with the resin content controlled at 35±2wt%, to obtain the middle fiber prepreg; the surface-modified ultra-high molecular weight polyethylene fibers are impregnated in the inner resin system, with the resin content controlled at 30±2wt%, to obtain the inner fiber prepreg.

[0023] S4. Layup Assembly: Following the direction from the blast-facing side to the back plate, lay out the outer layer of fiber prepreg (4 layers), interlayer toughening film, middle layer of fiber prepreg (6 layers), interlayer toughening film, and inner layer of fiber prepreg (4 layers) in sequence to form a composite panel preform. Place the preform into a hot press and cure it at 120℃ and 2.0MPa pressure for 4 hours. After naturally cooling to room temperature, demold to obtain the high-strength composite material panel for explosion-proof airtight doors.

[0024] Example 1

[0025] 100 parts of bisphenol A type epoxy resin (E-51); 17.5 parts of polyurethane prepolymer (polypropylene glycol (PPG, number average molecular weight 1000) was vacuum dehydrated at 110-120℃ for 1-2 hours, cooled to 50-60℃, and then toluene diisocyanate (TDI) was added, wherein the molar ratio of TDI to PPG was 2:1, and the reaction was carried out at 80-85℃ for 2-3 hours to obtain isocyanate-terminated polyurethane prepolymer); 27.5 parts of amine curing agent (curing agent 593); Accelerator (DMP-30) 1.5 parts; The mixed filler comprises the following components in parts by weight (based on 100 parts by weight of the matrix resin IPN): Mixed filler 1: 5 parts of fumed SiO2 (hydrophobic fumed silica, BET specific surface area 130±20 m²) 2 / g, surface-treated with dimethyldichlorosilane), 4 parts of organomontmorillonite OMMT (interlayer spacing ≥2.0nm); Mixed filler 2: 4.5 parts of nano-SiO2 (particle size 20-30nm) and 0.5 parts of graphene oxide (GO) (sheet size (0.5-5μm), monolayer ratio ≥95%); Mixed filler 3: 2.5 parts of nano SiO2 (particle size 20-30nm), 4 parts of T700 grade short-cut carbon fiber (3-6mm, epoxy sizing agent), and 4 parts of nano alumina (γ-Al2O3, particle size 20-30nm).

[0026] The dopamine modification agent on the surface of the fiber reinforcement layer was a Tris-HCl buffer solution of dopamine hydrochloride with pH=8.5 and a dopamine hydrochloride concentration of 1.8 g / L.

[0027] Among them, aramid fiber, glass fiber, and ultra-high molecular weight polyethylene fiber are all commercially available products, and the outer aramid fiber is made of plain weave fabric, 200g / m². 2 Specifications: The middle layer of fiberglass is made of plain weave fabric, 400g / m². 2 Specifications: The inner layer of UHMWPE fiber is made of plain weave fabric, 100g / m². 2 Specification.

[0028] Example 2

[0029] With other conditions remaining unchanged, the dopamine modification agent on the surface of the fiber reinforcement layer was a Tris-HCl buffer solution of dopamine hydrochloride, pH=8.5, and the concentration of dopamine hydrochloride was 2.0 g / L.

[0030] Example 3

[0031] 100 parts of bisphenol A type epoxy resin (E-51); Polyurethane prepolymer (17 parts) was prepared by vacuum dehydrating polypropylene glycol (PPG, number average molecular weight 1000) at 110–120 °C for 1–2 hours, cooling to 50–60 °C, adding toluene diisocyanate (TDI) in a molar ratio of TDI to PPG of 2:1, and reacting at 80–85 °C for 2–3 hours to obtain isocyanate-terminated polyurethane prepolymer. 25 parts of amine curing agent (curing agent 593); Accelerator (DMP-30) 1 part; The mixed filler comprises the following components in parts by weight (based on 100 parts by weight of the matrix resin IPN): Mixed filler 1: 3 parts of fumed SiO2 (hydrophobic fumed silica, BET specific surface area 130±20 m²) 2 / g, surface-treated with dimethyldichlorosilane), 3 parts of organomontmorillonite OMMT (interlayer spacing ≥2.0nm); Mixed filler 2: 3 parts of nano-SiO2 (particle size 20-30nm) and 0.1 parts of graphene oxide (GO) (sheet size 0.5-5μm, monolayer ratio ≥95%); Mixed filler 3: 2 parts of nano SiO2 (particle size 20-30nm), 3 parts of T700 grade short-cut carbon fiber (3-6mm, epoxy sizing agent), and 3 parts of nano alumina (γ-Al2O3, particle size 20-30nm).

[0032] The dopamine modification agent on the surface of the fiber reinforcement layer was a Tris-HCl buffer solution of dopamine hydrochloride with pH=8.5 and a dopamine hydrochloride concentration of 1.8 g / L.

[0033] Example 4

[0034] 100 parts of bisphenol A type epoxy resin (E-51); Polyurethane prepolymer (18 parts) was prepared by vacuum dehydrating polypropylene glycol (PPG, number average molecular weight 1000) at 110–120 °C for 1–2 hours, cooling to 50–60 °C, adding toluene diisocyanate (TDI) in a molar ratio of TDI to PPG of 2:1, and reacting at 80–85 °C for 2–3 hours to obtain isocyanate-terminated polyurethane prepolymer. 30 parts of amine curing agent (curing agent 593); Accelerator (DMP-30) 2 parts; The mixed filler comprises the following components in parts by weight (based on 100 parts by weight of the matrix resin IPN): Mixed filler 1: 7 parts of fumed SiO2 (hydrophobic fumed silica, BET specific surface area 130±20 m²) 2 / g, surface-treated with dimethyldichlorosilane), 5 parts of organomontmorillonite OMMT (interlayer spacing ≥2.0nm); Mixed filler 2: 6 parts of nano-SiO2 (particle size 20-30nm) and 1 part of graphene oxide (GO) (sheet size 0.5-5μm, monolayer ratio ≥95%); Mixed filler 3: 3 parts of nano SiO2 (particle size 20-30nm), 5 parts of T700 grade short-cut carbon fiber (3-6mm, epoxy sizing agent), and 5 parts of nano alumina (γ-Al2O3, particle size 20-30nm).

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that the fiber reinforcement layer was not treated with dopamine surface modification, i.e., step S1 was omitted, and the prepreg was prepared directly using untreated aramid fibers, glass fibers, and ultra-high molecular weight polyethylene fibers. The remaining steps are the same as in Example 1.

[0036] Comparative Example 2 The difference between this comparative example and Example 1 is that the resin matrix is ​​unmodified pure bisphenol A type epoxy resin E-51 (cured with 59,328 parts of curing agent, without polyurethane prepolymer or mixed filler), and no interlayer toughening film is set. The fiber reinforcement layers are directly stacked and then hot-pressed for curing. The remaining layup methods are the same as in Example 1.

[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that all fiber reinforcement layers use the same resin system (the outer resin system of Example 1), and no resin layer with graded properties is formed; no interlayer toughening film is provided. The layup method is aramid fiber layer / glass fiber layer / ultra-high molecular weight polyethylene fiber layer directly stacked (the number of layers is the same as in Example 1). The remaining steps are the same as in Example 1.

[0038] The composite material sheets prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to the following performance tests: (1) Interlaminar shear strength (ILSS): The test was conducted according to JC / T773-2010 "Fiber-reinforced plastic short beam method for determining interlaminar shear strength". The sample size was 20 mm long, 10 mm wide and 4 mm thick, with a span-to-thickness ratio of 5:1 and a loading speed of 2 mm / min.

[0039] (2) Impact strength: The impact strength test was carried out in accordance with GB / T1043.1-2008 "Determination of impact performance of plastic simply supported beams". The sample size was 80mm×10mm×4mm and the pendulum energy was 15J.

[0040] (3) Bending strength: The test was conducted in accordance with GB / T9341-2008 "Determination of bending properties of plastics". The sample size was 80mm×10mm×4mm, the span was 64mm, and the loading speed was 2mm / min.

[0041] (4) Glass transition temperature (Tg): Dynamic thermomechanical analysis (DMA) was used, with a test frequency of 1 Hz, a heating rate of 5 ℃ / min, and a temperature range of 30~200 ℃. The peak temperature of tanδ was taken as Tg.

[0042] (5) Interlaminar fracture toughness (Type I, GIC): Tested according to ASTM D5528-13 "Standard Test Method for Mode I Interlaminar Fracture Toughness of Unidirectional Fiber-Reinforced Polymer Matrix Composites".

[0043] The test data is shown in the table below:

[0044] As can be seen from the above data, the present invention, through the synergistic technical solution of "three-layer gradient fiber + homologous IPN matrix + gradient filler + dopamine modification of fiber surface + interlaminar toughening film", enables the interlaminar shear strength of the composite material to reach over 34.2 MPa and the impact strength to reach 85.6 kJ / m. 2The glass transition temperature reaches over 118.7℃, which is significantly higher than existing technologies (Comparative Example 2, interlaminar shear strength 16.8MPa, impact strength 42.5kJ / m). 2 Significant improvements have been made in the interlaminar shear strength (Tg 102.5℃), effectively solving technical problems such as low interlaminar shear strength, high brittleness, and insufficient heat resistance in existing technologies.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high-strength composite material for explosion-proof airtight doors, characterized in that: The composite material is a composite board, comprising several fiber reinforcement layers arranged sequentially from the blast-facing surface to the backing plate, and an interlayer toughening film sandwiched between adjacent fiber reinforcement layers; the fiber reinforcement layers form a gradient structure from the blast-facing surface to the backing plate, specifically including an outer aramid fiber layer, a middle glass fiber layer, and an inner ultra-high molecular weight polyethylene fiber layer; the fiber surfaces of the fiber reinforcement layers are modified with dopamine; each fiber reinforcement layer is impregnated with a modified resin matrix, and the interlayer toughening film and the fiber reinforcement layers are co-cured and molded together by hot pressing; the modified resin matrix is ​​an epoxy-polyurethane interpenetrating network resin system, and each fiber reinforcement layer is based on the same epoxy-polyurethane interpenetrating network as the base matrix, with different functional mixed fillers added sequentially to form a resin layer with gradient properties.

2. The high-strength composite material for an explosion-proof airtight door according to claim 1, characterized in that: The modified resin matrix includes a matrix resin IPN and mixed fillers: The matrix resin IPN comprises the following components in parts by weight: 100 parts of bisphenol A type epoxy resin; 17-18 parts of polyurethane prepolymer; 25-30 parts of amine curing agent; Accelerator (DMP-30) 1-2 parts; The mixed filler comprises the following components in parts by weight (based on 100 parts by weight of the matrix resin IPN): Mixed filler 1: 3-7 parts fumed SiO2, 3-5 parts organic montmorillonite (OMMT); Mixed filler 2: 3-6 parts nano-SiO2, 0.1-1 parts graphene oxide; Mixed filler 3: 2-3 parts nano SiO2, 3-5 parts short-cut carbon fiber, and 3-5 parts nano alumina.

3. The high-strength composite material for an explosion-proof airtight door according to claim 2, characterized in that: The polyurethane prepolymer is a terminal isocyanate prepolymer based on polypropylene glycol (PPG) and toluene diisocyanate (TDI), with a molar ratio of TDI to PPG of 2:

1.

4. The high-strength composite material for an explosion-proof airtight door according to claim 3, characterized in that: The nanofillers (including fumed SiO2, nano SiO2, GO, and nano Al2O3) need to be pretreated by ultrasonic dispersion or high-speed shear dispersion to ensure uniform dispersion in the resin matrix and avoid agglomeration.

5. The high-strength composite material for an explosion-proof airtight door according to claim 4, characterized in that: The bisphenol A type epoxy resin is E-51.

6. The high-strength composite material for an explosion-proof airtight door according to claim 5, characterized in that: The dopamine modification agent on the surface of the fiber reinforcement layer is a Tris-HCl buffer solution of dopamine hydrochloride with pH=8.5 and the concentration of dopamine hydrochloride is 1.5-2.0 g / L.

7. The high-strength composite material for an explosion-proof airtight door according to claim 6, characterized in that: The T700 grade short-cut carbon fiber.

8. The high-strength composite material for an explosion-proof airtight door according to claim 7, characterized in that: The amine curing agent is curing agent 593.

9. The high-strength composite material for an explosion-proof airtight door according to claim 8, characterized in that: The interlayer toughening film is a toughened modified epoxy resin film with a surface density of 150–250 g / m³. 2 The curing temperature is 100-150℃.

10. The high-strength composite material for an explosion-proof airtight door according to claim 9, characterized in that: The high-strength composite material is prepared through the following process steps: S1. Fiber surface modification: Aramid fiber, glass fiber and ultra-high molecular weight polyethylene fiber are respectively immersed in Tris-HCl buffer solution of dopamine hydrochloride and reacted at 20-30℃ for 20-28 hours. After being taken out, they are washed with deionized water and dried to obtain surface modified fiber. S2. Preparation of modified resin matrix: Weigh out bisphenol A type epoxy resin E-51, polyurethane prepolymer, amine curing agent and accelerator DMP-30 according to the mass parts, and mix them evenly to obtain matrix resin IPN; add the mass parts of mixed filler 1, mixed filler 2 and mixed filler 3 to the matrix resin IPN respectively, and perform ultrasonic dispersion or high-speed shear dispersion treatment to obtain outer layer resin system, middle layer resin system and inner layer resin system respectively; S3. Prepreg preparation: The surface-modified aramid fibers obtained in step S1 are impregnated in the outer resin system to obtain an outer fiber prepreg. Surface-modified glass fibers are impregnated in the intermediate layer resin system to obtain an intermediate layer fiber prepreg; surface-modified ultra-high molecular weight polyethylene fibers are impregnated in the inner layer resin system to obtain an inner layer fiber prepreg. S4. Lay-up assembly: Following the direction from the blast-facing side to the back panel, lay out the outer layer of fiber prepreg, the interlayer toughening film, the middle layer of fiber prepreg, the interlayer toughening film, and the inner layer of fiber prepreg in sequence to form a composite precast panel.

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