Interpenetrating phase composite explosion-proof shell based on foamed aluminum and modified polyurethane and preparation method thereof

Abstract

The application belongs to the technical field of coal mine underground electrical equipment protection, and particularly discloses an interpenetrating phase composite explosion-proof shell based on foamed aluminum and modified polyurethane and a preparation method thereof. The composite explosion-proof shell is formed by alternately stacking at least two foamed aluminum framework layers and at least one modified high-resilience polyurethane soft bubble cushion energy-absorbing layer along the thickness direction, and a modified high-resilience polyurethane soft bubble cushion energy-absorbing layer is arranged between the adjacent two foamed aluminum framework layers. The interpenetrating phase composite explosion-proof shell based on foamed aluminum and modified polyurethane and the preparation method thereof are adopted, the explosion-proof shell has a qualitative leap in explosion impact resistance, energy absorption efficiency and structural stability under the condition that the area is increased limitedly, and the shell body of the explosion-proof shell has the advantages of light weight, fire resistance and the like.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment protection technology in coal mines, specifically relating to an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane and its preparation method. Background Technology

[0002] With the increasing depth of coal mining, the working environment of underground electrical equipment is becoming increasingly harsh. High humidity, high dust levels, and frequent impact loads place higher demands on the comprehensive performance of explosion-proof enclosures. Currently, the explosion-proof enclosure materials used in underground mines in my country mainly fall into two categories: cast iron and aluminum alloy. While cast iron has advantages such as high strength, good heat dissipation, and low manufacturing cost, it also has inherent defects such as heavy weight and significant brittleness, which not only increases the difficulty of equipment handling and installation but also makes it prone to sudden fracture under impact loads. Although aluminum alloy solves the problems of lightweight and corrosion resistance and maintains good heat dissipation, its mechanical strength is insufficient, making it difficult to provide reliable explosion-proof protection in complex underground impact scenarios.

[0003] In existing technologies, single-metal materials can no longer meet the comprehensive performance requirements of "high strength, high temperature resistance, thermal shock resistance, lightweight, and corrosion resistance." Traditional composite materials often employ simple layered structures, which suffer from weak interfacial bonding, low energy transfer efficiency, and limited explosion-proof energy absorption. Therefore, there is an urgent need in this field to develop a novel explosion-proof shell material and its preparation method that combines structural stability and functional integration, effectively addressing the aforementioned problems. Summary of the Invention

[0004] The purpose of this invention is to provide an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane and its preparation method. With a limited increase in area, the explosion-proof shell achieves a qualitative leap in blast resistance, energy absorption efficiency and structural stability. At the same time, the shell of the explosion-proof shell also has the advantages of being lightweight and fire-retardant.

[0005] To achieve the above objectives, this invention provides an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane. The explosion-proof shell has a multi-layer structure, formed by alternatingly stacking at least two aluminum foam skeleton layers and at least one modified high-resilience polyurethane soft foam buffer energy-absorbing layer along the thickness direction, with a modified high-resilience polyurethane soft foam buffer energy-absorbing layer sandwiched between adjacent aluminum foam skeleton layers. Through a specific manufacturing process, the modified high-resilience polyurethane soft foam buffer energy-absorbing layer and the aluminum foam skeleton layer form an interpenetrating phase composite structure, thereby synergistically leveraging the high strength and high stiffness of aluminum foam and the excellent buffering and damping properties of modified polyurethane material.

[0006] A modified high-resilience polyurethane flexible foam buffer and energy-absorbing layer is filled into the spherical openings of the aluminum foam skeleton to form a three-dimensional interpenetrating phase composite structure. Among them, the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer accounts for 30%-39% of the pore volume of the aluminum foam skeleton layer, and the pore volume is the total volume of all spherical open pores in the aluminum foam skeleton.

[0007] Preferably, the modified high-resilience polyurethane flexible foam buffer energy absorption layer includes reinforcing fibers and flame-retardant materials; the volume content of the reinforcing fibers is 2.1% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer, and the volume content of the flame-retardant materials is 9.7% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer. Reinforcing fibers include carbon fiber and basalt fiber; flame-retardant materials include expandable graphite and dimethyl methylphosphonate.

[0008] Preferably, the volumetric content of carbon fiber is 0.6% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer, and the volumetric content of basalt fiber is 1.5% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer; wherein the length of both carbon fiber and basalt fiber is 6-9 mm. The volumetric content of expandable graphite is 3.3% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer, and the volumetric content of dimethyl methylphosphonate is 6.4% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer.

[0009] This invention also provides a method for preparing an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane, comprising the following steps: Step S1: Prepare a liquid-modified high-resilience polyurethane flexible foam buffer energy absorption layer; Step S2: Inject the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

[0010] The foamed aluminum skeleton is combined with a modified high-resilience polyurethane flexible foam with a specific formulation. This polyurethane flexible foam is not an ordinary material, but is modified with fiber reinforcement and flame retardant components, which significantly improves its mechanical properties and explosion resistance while maintaining high resilience.

[0011] Preferably, step S1 specifically includes: Step S11: Mix the highly active polyether polyol GEP-330N, polymer polyol POP36 / 28, bis(2-dimethylaminoethyl) ether, dipropylene glycol, diethanolamine, silicone oil Y-10366, distilled water, 80 / 20-toluene diisocyanate, and polymethylene polyphenyl isocyanate to obtain component A; Step S12: Mix diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate to obtain component B; Step S13: Add carbon fiber and / or basalt fiber to component A to obtain component C; Step S14: Use a high-speed mechanical stirrer to pre-disperse component C at a speed of 1000-1200 r / min for 30-60 s to ensure that the fibers are evenly dispersed and free of clumping. Step S15: Add expandable graphite and dimethyl methylphosphonate to component C and mix to obtain component D; Step S16: When the temperature of both component D and component B is adjusted to 23-27℃, quickly pour component B into component D and mix. Immediately stir with a stirrer at a speed of 1400r / min for 3-5 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S17: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid-modified high-resilience polyurethane soft foam buffer energy absorption layer.

[0012] Preferably, in step S11, component A comprises the following components by weight percentage: 34.1% of highly active polyether polyol GEP-330N, 34.1% of polymer polyol POP36 / 28, 0.1% of bis(2-dimethylaminoethyl) ether, 1.0% of dipropylene glycol, 1.7% of diethanolamine, 1.2% of silicone oil Y-10366, 1.9% of distilled water, 15.7% of 80 / 20-toluene diisocyanate, and 10.2% of polymethylene polyphenyl isocyanate.

[0013] Preferably, in step S12, component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

[0014] Preferably, step S2 specifically includes: Step S21: Inject the liquid modified high-resilience polyurethane flexible foam buffer energy absorption layer into the spherical openings of the aluminum foam skeleton at a uniform pressure of 0.5-1.5MPa. Step S22: Heat at 100℃ to expand and cure the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer for 3 hours.

[0015] A controllable injection molding and compression molding process was adopted. By precisely controlling the injection pressure, curing temperature and mold constraints, the expansion of the liquid modified high-resilience polyurethane flexible foam buffer energy absorption layer was hindered by the mold size. This allowed the liquid modified high-resilience polyurethane flexible foam layer next to the aluminum foam skeleton to be successfully squeezed into the aluminum foam skeleton, ensuring the full formation of the interpenetrating structure and the integrity of the composite material.

[0016] Liquid modified polyurethane material is injected into the continuous pores of aluminum foam under pressure and then solidifies. It not only fills the pores but also interweaves and interlocks with the aluminum foam skeleton in three-dimensional space, maximizing the interfacial bonding strength and forming a unique "hard-soft" interpenetrating phase composite structure. This avoids the risk of interlayer delamination and ensures high efficiency in energy transfer and dissipation.

[0017] The present invention employs the above-mentioned interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane and its preparation method, and the beneficial effects are as follows: (1) This invention innovatively combines modified high-resilience polyurethane flexible foam containing carbon fiber with aluminum foam to form an interpenetrating phase composite material, thus preparing a lightweight, high-performance explosion-proof shell suitable for downhole electrical equipment. The core material in this invention has a "shear thickening" characteristic, that is, when the material is subjected to high-speed impact, its internal microstructure will undergo dynamic reorganization, forming a denser and stronger temporary associative network, thereby instantly improving the overall stiffness and energy absorption capacity, and thus significantly enhancing the explosion-proof performance of the shell. At the same time, carbon fiber itself has lightweight, high strength and excellent corrosion resistance, further ensuring the long-term stability of the explosion-proof shell in harsh environments.

[0018] Therefore, the composite explosion-proof shell in this invention not only achieves multiple optimizations in material properties, but also effectively improves impact resistance through a unique shear thickening effect, providing reliable safety protection for downhole electrical equipment and showing good engineering application prospects.

[0019] (2) Carbon fiber has extremely high elastic modulus and tensile strength. In composite materials, carbon fiber acts like "steel bars," mainly providing strength support for crack bridging. This ensures that the material can still withstand higher loads after cracks appear, which is the basis for achieving "strain hardening" (i.e., the load does not decrease but increases). Basalt fiber has certain toughness and deformation capacity, which can more effectively transfer stress at the microscopic level, promote the generation of more microcracks, and delay the propagation of single cracks, thus contributing more deformation capacity.

[0020] When the two are blended, carbon fiber provides a "hard" skeleton, while basalt fiber provides a "tough" connection. This synergistic effect allows the composite material to meet both the strength requirements for strain hardening and the energy requirements for generating multiple fine cracks during tensile testing, thus stably achieving an ultimate tensile strain of more than 2% or even higher, which is significantly better than a single fiber system.

[0021] (3) Although carbon fiber has good performance, it is expensive. This invention reduces costs and obtains better mechanical properties by mixing basalt fiber with it in a certain proportion.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 The results of the dynamic impact test in Comparative Example 1 are for the interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane and its preparation method of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0026] Example 1 The preparation method of the explosion-proof shell based on interpenetrating phase composite of aluminum foam and modified polyurethane includes the following steps: Step S1: Prepare a liquid-modified high-resilience polyurethane flexible foam buffer energy absorption layer; Step S11: Prepare component A; component A comprises the following components by weight percentage: high-activity polyether polyol GEP-330N 34.1%, polymer polyol POP36 / 28 34.1%, bis(2-dimethylaminoethyl) ether 0.1%, dipropylene glycol 1.0%, diethanolamine 1.7%, silicone oil Y-10366 1.2%, distilled water 1.9%, 80 / 20-toluene diisocyanate 15.7%, and polymethylene polyphenyl isocyanate 10.2%.

[0027] Step S12: Prepare component B; component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

[0028] Step S13: Add carbon fibers with a fiber length of 6-9 mm and a volume fraction of 0.6% and basalt fibers with a volume fraction of 1.5% to component A and mix them to obtain component C; Step S14: Use a stirrer to pre-disperse component C at a speed of 1100 r / min for 40 s to ensure that the fibers are evenly dispersed and free of clumping. Step S15: Add expandable graphite with a volume content of 3.3% and dimethyl methylphosphonate with a volume content of 6.4% to component C and mix to obtain component D; Step S16: When the temperature of both component D and component B is adjusted to 25°C, quickly pour component B into component D and mix. Immediately stir with a stirrer at a speed of 1400 r / min for 4 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S17: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid-modified high-resilience polyurethane soft foam buffer energy absorption layer.

[0029] The total volumetric content of components A and B is 88.2% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer.

[0030] Step S2: Inject the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

[0031] Step S21: Inject a liquid modified high-resilience polyurethane flexible foam buffer energy absorption layer with a volume fraction of 35%-39% into the spherical opening of the aluminum foam skeleton at a uniform pressure of 1MPa. Step S22: Heating at 100℃ causes the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer to expand and solidify for 3 hours, thus obtaining an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

[0032] Example 2 The preparation method of the explosion-proof shell based on interpenetrating phase composite of aluminum foam and modified polyurethane includes the following steps: Step S1: Prepare a liquid-modified high-resilience polyurethane flexible foam buffer energy absorption layer; Step S11: Prepare component A; component A comprises the following components by weight percentage: high-activity polyether polyol GEP-330N 34.1%, polymer polyol POP36 / 28 34.1%, bis(2-dimethylaminoethyl) ether 0.1%, dipropylene glycol 1.0%, diethanolamine 1.7%, silicone oil Y-10366 1.2%, distilled water 1.9%, 80 / 20-toluene diisocyanate 15.7%, and polymethylene polyphenyl isocyanate 10.2%.

[0033] Step S12: Prepare component B; component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

[0034] Step S13: Add carbon fiber with a surface-treated volume fraction of 0.6% and basalt fiber with a volume fraction of 1.5% to component A and mix them to obtain component C; Step S14: Use a stirrer to pre-disperse component C at a speed of 1100 r / min for 40 s to ensure that the fibers are evenly dispersed and free of clumping. Step S15: Add expandable graphite with a volume content of 3.3% and dimethyl methylphosphonate with a volume content of 6.4% to component C and mix to obtain component D; Step S16: When the temperature of both component D and component B is adjusted to 25°C, quickly pour component B into component D and mix. Immediately stir with a stirrer at a speed of 1400 r / min for 4 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S17: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid-modified high-resilience polyurethane soft foam buffer energy absorption layer.

[0035] Step S2: Inject the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

[0036] Step S21: Inject a liquid modified high-resilience polyurethane flexible foam buffer energy absorption layer with a volume fraction of 30%-34% into the spherical opening of the aluminum foam skeleton at a uniform pressure of 1MPa. Step S22: Heating at 100℃ causes the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer to expand and solidify for 3 hours, thus obtaining an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

[0037] Comparative Example 1 A method for preparing an explosion-proof shell includes the following steps: Step S1: Prepare a liquid polyurethane flexible foam buffer energy absorption layer; Step S11: Prepare component A; component A comprises the following components by weight percentage: high-activity polyether polyol GEP-330N 34.1%, polymer polyol POP36 / 28 34.1%, bis(2-dimethylaminoethyl) ether 0.1%, dipropylene glycol 1.0%, diethanolamine 1.7%, silicone oil Y-10366 1.2%, distilled water 1.9%, 80 / 20-toluene diisocyanate 15.7%, and polymethylene polyphenyl isocyanate 10.2%.

[0038] Step S12: Prepare component B; component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

[0039] Step S13: Add carbon fiber with a surface-treated volume fraction of 2.1% to component A and mix to obtain component C; Step S14: Use a stirrer to pre-disperse component C at a speed of 1100 r / min for 40 s to ensure that the fibers are evenly dispersed and free of clumping. Step S15: Add expandable graphite with a volume content of 3.3% and dimethyl methylphosphonate with a volume content of 6.4% to component C and mix to obtain component D; Step S16: When the temperature of both component D and component B is adjusted to 25°C, quickly pour component B into component D and mix. Immediately stir with a stirrer at a speed of 1400 r / min for 4 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S17: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid polyurethane soft foam buffer energy absorption layer.

[0040] The total volumetric content of components A and B is 88.2% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer.

[0041] Step S2: Inject the liquid polyurethane flexible foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain the explosion-proof shell.

[0042] Step S21: Inject a liquid polyurethane flexible foam buffer energy absorption layer with a volume fraction of 35%-39% into the spherical opening of the aluminum foam skeleton at a uniform pressure of 1MPa. Step S22: Heat at 100℃ to expand and solidify the liquid polyurethane soft foam buffer energy-absorbing layer for 3 hours to obtain the explosion-proof shell.

[0043] Comparative Example 2 A method for preparing an explosion-proof shell includes the following steps: Step S1: Prepare a liquid polyurethane flexible foam buffer energy absorption layer; Step S11: Prepare component A; component A comprises the following components by weight percentage: high-activity polyether polyol GEP-330N 34.1%, polymer polyol POP36 / 28 34.1%, bis(2-dimethylaminoethyl) ether 0.1%, dipropylene glycol 1.0%, diethanolamine 1.7%, silicone oil Y-10366 1.2%, distilled water 1.9%, 80 / 20-toluene diisocyanate 15.7%, and polymethylene polyphenyl isocyanate 10.2%.

[0044] Step S12: Prepare component B; component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

[0045] Step S13: Add basalt fiber with a surface treatment volume of 2.1% to component A and mix to obtain component C; Step S14: Use a stirrer to pre-disperse component C at a speed of 1100 r / min for 40 s to ensure that the fibers are evenly dispersed and free of clumping. Step S15: Add expandable graphite with a volume content of 3.3% and dimethyl methylphosphonate with a volume content of 6.4% to component C and mix to obtain component D; Step S16: When the temperature of both component D and component B is adjusted to 25°C, quickly pour component B into component D and mix. Immediately stir with a stirrer at a speed of 1400 r / min for 4 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S17: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid polyurethane soft foam buffer energy absorption layer.

[0046] The total volumetric content of components A and B is 88.2% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer.

[0047] Step S2: Inject the liquid polyurethane flexible foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain the explosion-proof shell.

[0048] Step S21: Inject a liquid polyurethane flexible foam buffer energy absorption layer with a volume fraction of 35%-39% into the spherical opening of the aluminum foam skeleton at a uniform pressure of 1MPa. Step S22: Heat at 100℃ to expand and solidify the liquid polyurethane soft foam buffer energy-absorbing layer for 3 hours to obtain the explosion-proof shell.

[0049] Comparative Example 3 A method for preparing an explosion-proof shell includes the following steps: Step S1: Prepare a liquid polyurethane flexible foam buffer energy absorption layer; Step S11: Prepare component A; component A comprises the following components by weight percentage: high-activity polyether polyol GEP-330N 34.1%, polymer polyol POP36 / 28 34.1%, bis(2-dimethylaminoethyl) ether 0.1%, dipropylene glycol 1.0%, diethanolamine 1.7%, silicone oil Y-10366 1.2%, distilled water 1.9%, 80 / 20-toluene diisocyanate 15.7%, and polymethylene polyphenyl isocyanate 10.2%.

[0050] Step S12: Prepare component B; component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

[0051] Step S13: Add expandable graphite with a volume content of 3.3% and dimethyl methylphosphonate with a volume content of 6.4% to component A and mix to obtain component C; Step S14: When the temperature of both component C and component B is adjusted to 25°C, quickly pour component B into component C and mix. Immediately stir with a stirrer at a speed of 1400 r / min for 4 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S15: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid polyurethane soft foam buffer energy absorption layer.

[0052] The total volumetric content of components A and B is 90.3% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer.

[0053] Step S2: Inject the liquid polyurethane flexible foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain the explosion-proof shell.

[0054] Step S21: Inject a liquid polyurethane flexible foam buffer energy absorption layer with a volume fraction of 35%-39% into the spherical opening of the aluminum foam skeleton at a uniform pressure of 1MPa. Step S22: Heat at 100℃ to expand and solidify the liquid polyurethane soft foam buffer energy-absorbing layer for 3 hours to obtain the explosion-proof shell.

[0055] Comparative Example 4 A method for preparing an explosion-proof shell includes the following steps: Step S1: Prepare a liquid-modified high-resilience polyurethane flexible foam buffer energy absorption layer; Step S11: Prepare component A; component A comprises the following components by weight percentage: high-activity polyether polyol GEP-330N 34.1%, polymer polyol POP36 / 28 34.1%, bis(2-dimethylaminoethyl) ether 0.1%, dipropylene glycol 1.0%, diethanolamine 1.7%, silicone oil Y-10366 1.2%, distilled water 1.9%, 80 / 20-toluene diisocyanate 15.7%, and polymethylene polyphenyl isocyanate 10.2%.

[0056] Step S12: Prepare component B; component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

[0057] Step S13: Add carbon fiber with a surface-treated volume fraction of 0.6% and basalt fiber with a volume fraction of 1.5% to component A and mix them to obtain component C; Step S14: Use a stirrer to pre-disperse component C at a speed of 1100 r / min for 40 s to ensure that the fibers are evenly dispersed and free of clumping. Step S15: Add expandable graphite with a volume content of 3.3% and dimethyl methylphosphonate with a volume content of 6.4% to component C and mix to obtain component D; Step S16: When the temperature of both component D and component B is adjusted to 25°C, quickly pour component B into component D and mix. Immediately stir with a stirrer at a speed of 1400 r / min for 4 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S17: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid-modified high-resilience polyurethane soft foam buffer energy absorption layer.

[0058] The total volumetric content of components A and B is 88.2% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer.

[0059] Step S2: Inject the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

[0060] Step S21: Inject a liquid modified high-resilience polyurethane flexible foam buffer energy absorption layer with a volume fraction of 40%-44% into the spherical opening of the aluminum foam skeleton at a uniform pressure of 1MPa. Step S22: Heat at 100℃ to expand and cure the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer for 3 hours to obtain the explosion-proof shell.

[0061] Experimental Example 1 like Figure 1 As shown, the explosion-proof shells prepared in Examples 1-2 and Comparative Examples 1-4 were subjected to dynamic impact tests for analysis.

[0062] The Hopkinson bar test is a key technique that utilizes the propagation of stress waves in an elastic bar to measure the stress-strain response and energy absorption characteristics of materials under high-strain dynamic impact loads. When an external load attempts to induce high-speed shear deformation in a material, the material drastically increases its resistance to deformation through microstructural reorganization. This "hardening" process is itself a highly efficient energy dissipation process. Therefore, the energy absorption of the material involved in this invention is a result of the shear thickening effect within the material.

[0063] (1) Hopkinson bar tests were conducted on Example 1 and Comparative Examples 1-3. It was found that the energy absorption efficiency of Example 1 was 3%, 5% and 10% higher than that of Comparative Examples 1-3, respectively. The excellent energy absorption performance is an inevitable external manifestation of the material having a significant shear thickening effect. Therefore, Example 1 is feasible.

[0064] (2) Hopkinson bar tests were conducted on Examples 1, 2, and 4. It was found that under different volume fractions of modified high-resilience polyurethane flexible foam, Example 1, with a volume fraction of 35%-39%, showed a significant improvement in energy absorption efficiency compared to the other two groups. Therefore, the energy absorption effect was best when the volume fraction of modified high-resilience polyurethane flexible foam was 35%-39%, reflecting the thickening shear effect of the material.

[0065] Experiment Example 2 The density analysis of the explosion-proof shells prepared in Examples 1-2 and Comparative Examples 1-4 is shown in Table 1.

[0066] Table 1 Density Results

[0067] As shown in Table 1, the effect of fiber blending on the overall density of the composite material is minimal, with all groups maintaining low densities. This indicates that fiber reinforcement can significantly improve the mechanical properties of the material without significantly increasing its weight, thus achieving efficient lightweight design.

[0068] Therefore, the present invention adopts the above-mentioned interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane and its preparation method. With a limited increase in area, the explosion-proof shell achieves a qualitative leap in blast resistance, energy absorption efficiency and structural stability. At the same time, the shell of the explosion-proof shell also has the advantages of being lightweight and fire-retardant.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An explosion-proof shell based on interpenetrating phase composite of aluminum foam and modified polyurethane, characterized in that, The composite explosion-proof shell is formed by alternatingly stacking at least two layers of aluminum foam skeleton and at least one layer of modified high-resilience polyurethane soft foam buffer energy absorption layer along the thickness direction, and a modified high-resilience polyurethane soft foam buffer energy absorption layer is sandwiched between two adjacent aluminum foam skeleton layers. A modified high-resilience polyurethane flexible foam buffer and energy-absorbing layer is filled into the spherical openings of the aluminum foam skeleton to form a three-dimensional interpenetrating phase composite structure. Among them, the volume of the modified high-resilience polyurethane soft foam buffer energy absorption layer accounts for 30%-39% of the pore volume of the aluminum foam skeleton layer, and the pore volume is the total volume of all spherical open pores in the aluminum foam skeleton. The modified high-resilience polyurethane flexible foam buffer energy absorption layer includes reinforcing fibers and flame-retardant materials; the volume content of reinforcing fibers is 2.1% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer, and the reinforcing fibers include carbon fiber and basalt fiber; The volumetric content of carbon fiber is 0.6% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer, and the volumetric content of basalt fiber is 1.5% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer; the length of both carbon fiber and basalt fiber is 6-9 mm.

2. The explosion-proof shell based on interpenetrating phase composite of aluminum foam and modified polyurethane according to claim 1, characterized in that: The volumetric content of the flame-retardant material is 9.7% of the volume of the modified high-resilience polyurethane flexible foam buffer energy-absorbing layer; Flame-retardant materials include expandable graphite and dimethyl methylphosphonate.

3. The explosion-proof shell based on interpenetrating phase composite of aluminum foam and modified polyurethane according to claim 2, characterized in that: The volumetric content of expandable graphite is 3.3% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer, and the volumetric content of dimethyl methylphosphonate is 6.4% of the volume of the modified high-resilience polyurethane flexible foam buffer energy absorption layer.

4. The method for preparing an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane as described in any one of claims 1-3, characterized in that, Includes the following steps: Step S1: Prepare a liquid-modified high-resilience polyurethane flexible foam buffer energy absorption layer; Step S2: Inject the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer into the aluminum foam skeleton layer to obtain an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

5. The method for preparing an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane according to claim 4, characterized in that, Step S1 is as follows: Step S11: Mix the highly active polyether polyol GEP-330N, polymer polyol POP36 / 28, bis(2-dimethylaminoethyl) ether, dipropylene glycol, diethanolamine, silicone oil Y-10366, distilled water, 80 / 20-toluene diisocyanate, and polymethylene polyphenyl isocyanate to obtain component A; Step S12: Mix diphenylmethane diisocyanate and polymethylene polyphenyl isocyanate to obtain component B; Step S13: Add carbon fiber and basalt fiber to component A and mix to obtain component C; Step S14: Use a stirrer to pre-disperse component C at a speed of 1000-1200 r / min for 30-60 seconds to ensure that the fibers are evenly dispersed and free of clumping. Step S15: Add expandable graphite and dimethyl methylphosphonate to component C and mix to obtain component D; Step S16: When the temperature of both component D and component B is adjusted to 23-27℃, quickly pour component B into component D and mix. Immediately stir with a stirrer at a speed of 1400r / min for 3-5 seconds, and immediately pour into an iron mold coated with release agent for foaming. Step S17: Place the foamed material in a forced-air drying oven at 55°C for 2 hours to mature, thereby obtaining the liquid-modified high-resilience polyurethane soft foam buffer energy absorption layer.

6. The method for preparing an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane according to claim 5, characterized in that, In step S11, component A comprises the following components by weight percentage: 34.1% of highly active polyether polyol GEP-330N, 34.1% of polymer polyol POP36 / 28, 0.1% of bis(2-dimethylaminoethyl) ether, 1.0% of dipropylene glycol, 1.7% of diethanolamine, 1.2% of silicone oil Y-10366, 1.9% of distilled water, 15.7% of 80 / 20-toluene diisocyanate, and 10.2% of polymethylene polyphenyl isocyanate.

7. The method for preparing an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane according to claim 5, characterized in that: In step S12, component B comprises the following components by weight percentage: 88.1% diphenylmethane diisocyanate and 11.9% polymethylene polyphenyl isocyanate.

8. The method for preparing an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane according to claim 4, characterized in that, Step S2 is as follows: Step S21: Inject the liquid modified high-resilience polyurethane flexible foam buffer energy absorption layer into the spherical openings of the aluminum foam skeleton at a uniform pressure of 0.5-1.5MPa. Step S22: Heating at 100℃ causes the liquid modified high-resilience polyurethane soft foam buffer energy absorption layer to expand and solidify for 3 hours, thus obtaining an interpenetrating phase composite explosion-proof shell based on aluminum foam and modified polyurethane.

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