Ultra-light high-strength polyolefin foaming insulating material for unmanned aerial vehicle and preparation method and application of ultra-light high-strength polyolefin foaming insulating material

Abstract

The invention provides an ultra-light high-strength polyolefin foaming insulating material for an unmanned aerial vehicle, a preparation method of the ultra-light high-strength polyolefin foaming insulating material and a cable, and belongs to the technical field of polyolefin foaming insulating materials. The silicon dioxide nanorod with a pore structure is prepared from P123 / hydrochloric acid / tetraethoxysilane, and organosilane is introduced for modification, so that the dispersity of the silicon dioxide nanorod in polyolefin is improved, and a small amount of-NH2 is introduced as an anchor point for interface association with zinc ionized polypropylene wax; neutralizing maleic anhydride grafted polypropylene wax by using zinc acetate to obtain zinc ionized polypropylene wax containing Zn < 2 + >-carboxylate ion clusters; high-melt-strength polypropylene and metallocene polyethylene are blended, surface modified silicon dioxide nanorods and zinc ionized polypropylene wax are added, a local network is formed in a melt, and an antioxidant and a supercritical nitrogen foaming process are matched, so that the high-melt-strength polypropylene / zinc ionized polypropylene composite material is obtained. And the foaming insulating material with low density, low dielectric, high strength and good flexibility is realized under a fine and uniform foam structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyolefin foamed insulation materials, and relates to an ultra-light high-strength polyolefin foamed insulation material for a drone as well as a preparation method and application thereof. BACKGROUND

[0002] With the wide application of drones in the fields of logistics, surveying and mapping and inspection, higher technical indicators are put forward for the weight reduction of the airborne electronic and electrical architecture. As the carrier for power transmission and signal transmission of the drone, the weight of the cable directly affects the endurance and payload of the aircraft. The density of the traditional solid polyolefin insulation material cannot meet the demand of aviation-level lightweight. Therefore, the preparation of ultra-light polyolefin insulation material by using the microcellular foaming technology has become a research hotspot in the field of material science.

[0003] However, while achieving high foaming ratio, the existing polyolefin foamed material still has some deficiencies in preparation and application: first, with the increase of the foaming ratio, the bubble wall thickness decreases. In the foaming process of the traditional polypropylene or polyethylene matrix, the bubble wall often ruptures or merges due to the insufficient melt strength, resulting in a decrease in the closed cell rate. At the same time, due to the lack of effective rigid support structure, the tensile strength, wear resistance and compressive strength of the high foaming material usually decrease, which is difficult to adapt to the mechanical stress requirements of the drone under the complex flight conditions.

[0004] Secondly, in order to improve the strength, the existing technology often modifies by adding inorganic nano fillers (such as nano silicon dioxide, talc powder, etc.). However, the hydrophilic inorganic particles are prone to agglomeration in the non-polar polyolefin matrix, resulting in uneven dispersion. This not only cannot play a reinforcing role, but the agglomerates will become stress concentration points, pierce the bubble wall and cause the closed cell rate to decrease. In addition, the modification of the traditional silane coupling agent can only provide weak interfacial bonding force and cannot limit the slip of the polymer chain at the microscale, so the reinforcing effect is limited. SUMMARY

[0005] In view of the above problems, the purpose of the present application is to provide an ultra-light high-strength polyolefin foamed insulation material for a drone as well as a preparation method and application thereof. The present application prepares silica nanorods with pore structure by using a P123 / hydrochloric acid / orthosilicic acid ethyl ester system, and co-modifies them by using long-chain alkyl / amino silane to improve their dispersibility in polyolefin and introduce a small amount of -NH2 as an anchor point for the interface association with zinc ionized polypropylene wax; the maleic anhydride grafted polypropylene wax is neutralized by zinc acetate to convert the anhydride / carboxyl into Zn 2+Carboxylate salts, zinc ionized polypropylene waxes that form local ionic clusters, provide reversible physical crosslinking in the melt. High melt strength polypropylene is blended with metallocene polyethylene and surface modified silica nanorods and zinc ionized polypropylene waxes are introduced to build local networks that enhance melt strength, suppress cell growth and collapse and stabilize rheology and electrical properties with antioxidants; supercritical nitrogen is injected into dry masterbatches and temperature and pressure are controlled to utilize fine and uniform cell structure and enhanced cell wall support to reduce density and dielectric constant while maintaining good tensile strength, flexibility and insulation properties.

[0006] To achieve the above object, the present application adopts the following technical solutions: In a first aspect, the present application provides a preparation method of an ultra-light high-strength polyolefin foaming insulation material for a UAV, which comprises: S1: P123 is added to a hydrochloric acid solution to obtain a precursor solution by adding tetraethyl orthosilicate, and a reaction liquid A is obtained by stirring and hydrolyzing, and then the reaction liquid A is crystallized after being heated and placed, washed, and dried to obtain a primary product, and the primary product is calcined to obtain silica nanorods; a toluene dispersion solution of the silica nanorods is prepared, and a mixed modifier is added to obtain a reaction liquid B, and then the reaction liquid B is reacted, and after Soxhlet extraction, vacuum drying is performed to obtain surface-modified silica nanorods; S2: maleic anhydride grafted polypropylene wax is placed in a reaction kettle to obtain a melt, and zinc acetate is added under a nitrogen atmosphere to obtain a reaction liquid C, and then the reaction liquid C is vacuumized to remove by-products, and then the reaction liquid C is cooled and crushed to obtain zinc ionized polypropylene wax; S3: high melt strength polypropylene is mixed with metallocene polyethylene to obtain a base resin, and then surface-modified silica nanorods, zinc ionized polypropylene wax, and an antioxidant are added to obtain a mixture, and then the mixture is blended in a twin-screw extruder, and then the mixture is extruded and granulated to obtain a composite masterbatch, and then the composite masterbatch is vacuum dried to obtain a dried masterbatch; S4: the dried masterbatch is put into a single-screw extrusion foaming machine, and then supercritical nitrogen is injected into the melt to obtain a melt, and then the melt is cooled in a cooling section, and then the melt is extruded and released to foam to obtain an extrudate, and then the extrudate is shaped and flattened to obtain an ultra-light high-strength polyolefin foaming insulation material for a UAV.

[0007] As a preferred technical solution of the present application, in step S1, the concentration of the hydrochloric acid solution is 1.5-2.5M, for example, it can be 1.5M, 1.6M, 1.7M, 1.8M, 1.9M, 2.0M, 2.1M, 2.2M, 2.3M, 2.4M or 2.5M, but it is not limited to the listed values, and other values not listed in this range are also applicable.

[0008] In some optional embodiments, the mass ratio of the P123, the hydrochloric acid solution and the tetraethyl orthosilicate is 1 : (65-85) : (2.0-2.5), which can be 1 : (65, 67, 69, 71, 73, 75, 77, 79, 81, 83 or 85) : (2.00, 2.05, 2.10, 2.15, 2.20, 2.25, 2.30, 2.35, 2.40, 2.45 or 2.50), but is not limited to the listed values, and other values not listed in the range are also applicable.

[0009] In some optional embodiments, the temperature of the stirring hydrolysis of the precursor solution is 35-40°C, which can be 35.0°C, 35.5°C, 36.0°C, 36.5°C, 37.0°C, 37.5°C, 38.0°C, 38.5°C, 39.0°C, 39.5°C or 40.0°C, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0010] In some optional embodiments, the time of the stirring hydrolysis of the precursor solution is 20-24h, which can be 20.0h, 20.4h, 20.8h, 21.2h, 21.6h, 22.0h, 22.4h, 22.8h, 23.2h, 23.6h or 24.0h, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0011] In some optional embodiments, the temperature of the static crystallization of the reaction solution A is 90-100°C, which can be 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C or 100°C, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0012] In some optional embodiments, the time of the static crystallization of the reaction solution A is 24-48h, which can be 24.0h, 26.4h, 28.8h, 31.2h, 33.6h, 36.0h, 38.4h, 40.8h, 43.2h, 45.6h or 48.0h, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0013] In some alternative embodiments, the initial product is calcined at a temperature of 550-600 °C, for example, it can be 550 °C, 555 °C, 560 °C, 565 °C, 570 °C, 575 °C, 580 °C, 585 °C, 590 °C, 595 °C, or 600 °C, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0014] In some alternative embodiments, the initial product is calcined at a temperature of 550-600 °C, for example, it can be 550 °C, 555 °C, 560 °C, 565 °C, 570 °C, 575 °C, 580 °C, 585 °C, 590 °C, 595 °C, or 600 °C, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0015] In some alternative embodiments, the initial product is calcined for a time of 5-6 h, for example, it can be 5.0 h, 5.1 h, 5.2 h, 5.3 h, 5.4 h, 5.5 h, 5.6 h, 5.7 h, 5.8 h, 5.9 h, or 6.0 h, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0016] In some alternative embodiments, the mass volume ratio of the silica nanorods to toluene is 1 g: (20-30) mL, for example, it can be 1 g:20 mL, 1 g:21 mL, 1 g:22 mL, 1 g:23 mL, 1 g:24 mL, 1 g:25 mL, 1 g:26 mL, 1 g:27 mL, 1 g:28 mL, 1 g:29 mL, or 1 g:30 mL, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0017] In some alternative embodiments, the molar ratio of hexadecyltriethoxysilane to 3- aminopropyltriethoxysilane in the mixing modifier is (1-3): 1, for example, it can be 1.0:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2.0:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, or 3.0:1, but not limited to the listed values, other values not listed in the range of values are also applicable.

[0018] In some optional embodiments, the mass ratio of the mixing modifier to the silica nanorod is (0.3-0.6): 1, which can be 0.30: 1, 0.33: 1, 0.36: 1, 0.39: 1, 0.42: 1, 0.45: 1, 0.48: 1, 0.51: 1, 0.54: 1, 0.57: 1, or 0.60: 1, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0019] In some optional embodiments, the temperature of the reaction of the reaction solution B is 105-110℃, which can be 105.0℃, 105.5℃, 106.0℃, 106.5℃, 107.0℃, 107.5℃, 108.0℃, 108.5℃, 109.0℃, 109.5℃, or 110.0℃, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0020] In some optional embodiments, the time of the reaction of the reaction solution B is 12-24h, which can be 12.0h, 13.2h, 14.4h, 15.6h, 16.8h, 18.0h, 19.2h, 20.4h, 21.6h, 22.8h, or 24.0h, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0021] As a preferred technical solution of the present application, in step S2, the temperature of the melting of the maleic anhydride grafted polypropylene wax is 170-190℃, which can be 170℃, 172℃, 174℃, 176℃, 178℃, 180℃, 182℃, 184℃, 186℃, 188℃, or 190℃, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0022] In some optional embodiments, the zinc acetate is added to the melt in 2-4 times, which can be added in 2.0 times, 3.0 times, or 4.0 times, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0023] In some optional embodiments, the mass ratio of the zinc acetate to the maleic anhydride grafted polypropylene wax is (3-8): 100, which can be 3.0: 100, 3.5: 100, 4.0: 100, 4.5: 100, 5.0: 100, 5.5: 100, 6.0: 100, 6.5: 100, 7.0: 100, 7.5: 100, or 8.0: 100, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0024] In some optional embodiments, the reaction liquid C is reacted for 1-2 hours, for example, 1.0 hour, 1.1 hour, 1.2 hour, 1.3 hour, 1.4 hour, 1.5 hour, 1.6 hour, 1.7 hour, 1.8 hour, 1.9 hour or 2.0 hour, but not only limited to the listed values, other values not listed in the range are also applicable.

[0025] In some optional embodiments, the pressure of the vacuum extraction after the reaction of the reaction liquid C is -0.08~-0.09 MPa, for example, -0.090 MPa, -0.089 MPa, -0.088 MPa, -0.087 MPa, -0.086 MPa, -0.085 MPa, -0.084 MPa, -0.083 MPa, -0.082 MPa, -0.081 MPa or -0.080 MPa, but not only limited to the listed values, other values not listed in the range are also applicable.

[0026] In some optional embodiments, the time of the vacuum extraction after the reaction of the reaction liquid C is 30-60 minutes, for example, 30 minutes, 33 minutes, 36 minutes, 39 minutes, 42 minutes, 45 minutes, 48 minutes, 51 minutes, 54 minutes, 57 minutes or 60 minutes, but not only limited to the listed values, other values not listed in the range are also applicable.

[0027] As a preferred technical solution of the present application, in step S3, the mass ratio of the high melt strength polypropylene to the metallocene polyethylene is (70-90):(30-10), for example, (70, 72, 74, 76, 78, 80, 82, 84, 86, 88 or 90):(30, 28, 26, 24, 22, 20, 18, 16, 14, 12 or 10), but not only limited to the listed values, other values not listed in the range are also applicable.

[0028] In some optional embodiments, the mass ratio of the surface-modified silicon dioxide nanorod to the matrix resin is (1-5):100, for example, 1.0:100, 1.4:100, 1.8:100, 2.2:100, 2.6:100, 3.0:100, 3.4:100, 3.8:100, 4.2:100, 4.6:100 or 5.0:100, but not only limited to the listed values, other values not listed in the range are also applicable.

[0029] In some alternative embodiments, the mass ratio of the zinc-ionized polypropylene wax to the base resin is (2-8): 100, for example, it can be 2.0: 100, 2.6: 100, 3.2: 100, 3.8: 100, 4.4: 100, 5.0: 100, 5.6: 100, 6.2: 100, 6.8: 100, 7.4: 100, or 8.0: 100, but not limited to the listed values, other values not listed in the range are also applicable.

[0030] The antioxidant is a mixture of antioxidant 1010 and antioxidant 168 with a mass ratio of 1:1.

[0031] In some alternative embodiments, the mass ratio of the antioxidant to the base resin is (0.2-0.5): 100, for example, it can be 0.20: 100, 0.23: 100, 0.26: 100, 0.29: 100, 0.32: 100, 0.35: 100, 0.38: 100, 0.41: 100, 0.44: 100, 0.47: 100, or 0.50: 100, but not limited to the listed values, other values not listed in the range are also applicable.

[0032] In some alternative embodiments, the temperature of the mixture blending is 190-210°C, for example, it can be 190°C, 192°C, 194°C, 196°C, 198°C, 200°C, 202°C, 204°C, 206°C, 208°C, or 210°C, but not limited to the listed values, other values not listed in the range are also applicable.

[0033] In some alternative embodiments, the temperature of the vacuum drying of the composite master batch is 100-120°C, for example, it can be 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C, or 120°C, but not limited to the listed values, other values not listed in the range are also applicable.

[0034] In some alternative embodiments, the time of the vacuum drying of the composite master batch is 4-6h, for example, it can be 4.0h, 4.2h, 4.4h, 4.6h, 4.8h, 5.0h, 5.2h, 5.4h, 5.6h, 5.8h, or 6.0h, but not limited to the listed values, other values not listed in the range are also applicable.

[0035] As a preferred technical solution of the present application, in step S4, the temperature of the dried master batch melting is 200-220℃, for example, it can be 200℃, 202℃, 204℃, 206℃, 208℃, 210℃, 212℃, 214℃, 216℃, 218℃ or 220℃, but not limited to the listed values, other values not listed in this range are also applicable.

[0036] In some alternative embodiments, the mass ratio of the nitrogen gas to the dried master batch is (0.5-2.0):100, for example, it can be 0.50:100, 0.65:100, 0.80:100, 0.95:100, 1.10:100, 1.25:100, 1.40:100, 1.55:100, 1.70:100, 1.85:100 or 2.00:100, but not limited to the listed values, other values not listed in this range are also applicable.

[0037] In some alternative embodiments, the melt is cooled to 160-175℃ in the cooling section, for example, it can be cooled to 160.0℃, 161.5℃, 163.0℃, 164.5℃, 166.0℃, 167.5℃, 169.0℃, 170.5℃, 172.0℃, 173.5℃ or 175.0℃, but not limited to the listed values, other values not listed in this range are also applicable.

[0038] In some alternative embodiments, the pressure at the exit of the head of the single-screw extrusion foaming machine is 10-18MPa, for example, it can be 10.0MPa, 10.8MPa, 11.6MPa, 12.4MPa, 13.2MPa, 14.0MPa, 14.8MPa, 15.6MPa, 16.4MPa, 17.2MPa or 18.0MPa, but not limited to the listed values, other values not listed in this range are also applicable.

[0039] In some alternative embodiments, the rate of pressure release is 50-150MPa / s, for example, it can be 50MPa / s, 60MPa / s, 70MPa / s, 80MPa / s, 90MPa / s, 100MPa / s, 110MPa / s, 120MPa / s, 130MPa / s, 140MPa / s or 150MPa / s, but not limited to the listed values, other values not listed in this range are also applicable.

[0040] In the second aspect, the present application provides an ultra-light high-strength polyolefin foaming insulation material for unmanned aerial vehicles.

[0041] The application uses high melt strength polypropylene and metallocene polyethylene as polyolefin base resin, surface modified silica nanorods and zinc ionized polypropylene wax as structure regulating additives, and cooperates with supercritical nitrogen physical foaming process to construct a foaming insulating material with low density, high melt strength, good mechanical properties and insulation properties, which is used for unmanned aerial vehicle cable.

[0042] The application uses P123 / hydrochloric acid / orthosilicic acid ethyl ester system to prepare silica nanorods. P123 forms ordered micelles in acidic aqueous solution, orthosilicic acid ethyl ester is hydrolyzed and polycondensed around the micelles, and is further ordered and stacked in the crystallization stage at 90-100 DEG C, to finally form an inorganic / organic composite primary product. After washing and drying, slow temperature rising calcination is performed to remove the P123 organic template and promote further polycondensation of Si-OH into a stable Si-O-Si skeleton, to obtain silica nanorods with certain pore structure. The one-dimensional rigid particles can act as heterogeneous nucleating agents in the subsequent foaming process, increasing the number of nucleation and refining the cells, and can also play the role of "micro-scale support rib" in the cell wall. In the subsequent silane modification step in toluene, hexadecyl triethoxysilane and 3-aminopropyl triethoxysilane are introduced, and a layer of organic interface layer is formed on the surface of the nanorods through hydrolysis-condensation of silane and co-condensation with Si-OH. The long-chain alkyl segment improves the wettability and dispersibility of the inorganic rod in the polyolefin melt, reducing the risk of agglomeration during processing; a small amount of distributed -NH2 groups act as anchoring points for subsequent interface association with zinc ionized polypropylene wax, which is conducive to the construction of a stable rod-matrix interface structure.

[0043] The application neutralizes maleic anhydride grafted polypropylene wax with zinc acetate, converts the originally relatively free polar anhydride / carboxyl into Zn 2+ -carboxylate form, so that the polypropylene wax has ion aggregation ability. Melting the maleic anhydride grafted polypropylene wax provides diffusion and reaction conditions for hydrolysis of the anhydride group and acid-base exchange with zinc acetate. Zinc acetate reacts with the carboxylate group generated by the ring opening of the anhydride in the molten system to form a zinc carboxylate structure, while generating volatile byproducts such as acetic acid, which can be removed by subsequent vacuum extraction under negative pressure, reducing the impact of residual small molecules on the thermal stability and odor of the system. The obtained zinc ionized polypropylene wax still has a polypropylene structure on the molecular main chain, and has good compatibility with the high melt strength polypropylene and metallocene polyethylene matrix, but the Zn 2+ -carboxylate microzone introduced on the end group or side chain can form local ion clusters in the melt, showing reversible physical crosslinking characteristics similar to ionomers, to some extent improving the melt strength.

[0044] This application blends high melt strength polypropylene with metallocene polyethylene to form a matrix resin system that possesses both high melt strength and a certain degree of flexibility. High melt strength polypropylene provides long-chain branching and high melt elasticity, laying the foundation for stable cell structure at high foaming ratios; metallocene polyethylene improves the material's toughness and low-temperature resistance under actual bending and winding conditions. During twin-screw extrusion, surface-modified silica nanorods and zinc-ionized polypropylene wax are introduced into the melt. Utilizing the shearing and mixing action of the screw, the nanorods are uniformly dispersed in the matrix, while simultaneously promoting the growth of Zn... 2+ The carboxylate microdomains interact with the amino groups on the nanorod surface through multiple non-covalent interactions, including coordination, electrostatics, and hydrogen bonding. This allows the zinc-ionized polypropylene wax to spatially bridge the surface-modified silica nanorods and polyolefin matrix segments, forming localized physical cross-linking nodes. This helps to restrict local segment flow in the molten state, effectively suppressing excessive cell growth, merging, and collapse during foaming. Antioxidants inhibit free radical oxidation and peroxide decomposition during the blending extrusion process, reducing the thermo-oxidative degradation of high melt strength polypropylene and metallocene polyethylene, maintaining the stability of melt rheological behavior and the final material's mechanical and electrical properties. Subsequent vacuum drying of the composite masterbatch effectively removes moisture adsorbed near the nanorod pores and ionic groups, reducing bubble anomalies or dielectric property fluctuations caused by moisture in subsequent foaming stages.

[0045] This application involves melting the dried composite masterbatch in a single-screw extruder and injecting supercritical nitrogen gas. The melt is cooled in a cooling section, increasing its viscosity and elasticity. The long-chain branched structure of the high melt strength polypropylene, combined with Zn... 2+ The localized physical cross-linking network composed of carboxylate microregions, nanorods, and matrix chains collectively enhances the melt's load-bearing capacity under tension and shear, providing support for subsequent bubble nucleation and stabilization. When the melt is depressurized from the die outlet, the system reaches a supersaturated state, and nitrogen gas precipitates from the melt and undergoes nucleation and expansion. Surface-modified silica nanorods provide heterogeneous nucleation sites for bubbles, which is beneficial for increasing nucleation density, reducing bubble size, and improving bubble uniformity. During extrusion and stretching, the nanorods tend to exhibit a certain degree of orientation along the flow direction and bubble wall tangentially. Combined with the constraint effect of local ion association points on the movement of matrix chain segments, this results in a relatively enhanced microscopic support structure in the bubble wall region, thus maintaining bubble continuity and bubble wall integrity even at high foaming ratios. Macroscopically, the formation of a porous structure containing a large amount of gas phase within the material reduces density and relative permittivity. Simultaneously, relying on the mechanical properties of the matrix resin, the rigid support of the nanorods, and the ion-association-enhanced melt network, it helps to reduce density while maintaining the material's tensile strength, flexibility, and insulation properties.

[0046] In a third aspect, the application provides a cable prepared by using the ultra-light high-strength polyolefin foaming insulation material prepared by the preparation method.

[0047] Compared with the prior art, the application has the following beneficial effects: The application first prepares one-dimensional silica nanorods with pore structure by a P123 / hydrochloric acid / ethyl orthosilicate system, which is used as a heterogeneous nucleating agent and a bubble wall support skeleton in the foaming process; then the surface of the one-dimensional silica nanorods is co-modified by hexadecyl triethoxysilane and 3-aminopropyl triethoxysilane, which improves the dispersibility of the one-dimensional silica nanorods in the polyolefin melt and introduces a small amount of -NH2 as an anchoring point for interfacial association with the zinc ionized polypropylene wax.

[0048] The application neutralizes maleic anhydride grafted polypropylene wax by zinc acetate, converts anhydride / carboxyl into Zn 2+ -carboxylate, which enables the zinc ionized polypropylene wax to form local ionic clusters while maintaining the compatibility of the polypropylene main chain. The zinc ionized polypropylene wax exhibits reversible physical crosslinking similar to ionic polymers in the melt, which helps to improve the melt strength of the system.

[0049] The application constructs a base resin with high melt strength and flexibility by blending high melt strength polypropylene and metallocene polyethylene, introduces surface modified silica nanorods and zinc ionized polypropylene wax, and forms a local physical crosslinking network in a twin-screw extruder, which helps to improve the melt strength and to a certain extent, suppresses the bubble growth, merging and collapse in the foaming process, and on the other hand, cooperates with the antioxidant to inhibit thermal oxidative degradation, stabilize the rheological and electrical properties; subsequent vacuum drying removes the adsorbed water, reduces the risk of bubble defects and dielectric fluctuations.

[0050] The application injects supercritical nitrogen into the dried composite master batch and controls the temperature and pressure to realize the nucleation and growth of fine and uniform bubbles; relies on the local network of high melt strength polypropylene, silica nanorods and Zn 2+ -carboxylate to improve the melt bearing capacity and bubble wall support, so that the material can obtain high foaming, porous low dielectric structure, reduce the density, and still maintain good tensile strength, flexibility and insulation performance. DETAILED DESCRIPTION

[0051] The technical solutions of the present application will be described in detail below with specific examples. The examples described herein are specific embodiments of the present application, which are used to illustrate the concept of the present application; these descriptions are all explanatory and exemplary, and should not be understood as limiting the embodiments of the present application and the protection scope of the present application. In addition to the examples described herein, those skilled in the art can also employ other technical solutions that are obvious based on the content disclosed in the claims and the description of the present application, which include technical solutions that make any obvious substitutions and modifications to the examples described herein.

[0052] The chemical reagents used in the examples and comparative examples of the present application are all commercially available products without further purification or treatment.

[0053] Example 1 The present example provides a kind of ultra-lightweight high-strength polyolefin foaming insulating material for unmanned aerial vehicle and its preparation method, the preparation method of the ultra-lightweight high-strength polyolefin foaming insulating material for unmanned aerial vehicle specifically includes the following steps: S1: P123 is added to a 2.3M hydrochloric acid solution, and tetraethyl orthosilicate is added to obtain a precursor solution, wherein the mass ratio of P123, hydrochloric acid solution and tetraethyl orthosilicate is 1:75:2.1, hydrolysis is carried out at 39℃ for 22h to obtain reaction liquid A, and the temperature is raised to 95℃ and crystallization is carried out for 40h, then washed and dried to obtain a primary product, which is calcined at a temperature raising rate of 1.5℃ / min to 590℃ for 5.5h to obtain silica nanorods; a toluene dispersion of silica nanorods is prepared, and a mixed modifier is added to obtain reaction liquid B, wherein the mass-volume ratio of silica nanorods and toluene is 1g:27mL, the mixed modifier is composed of hexadecyl triethoxysilane and 3-aminopropyl triethoxysilane at a molar ratio of 2.8:1, and the mass ratio of mixed modifier to silica nanorods is 0.55:1, and the reaction is carried out at 109℃ for 18h, and then vacuum dried after Soxhlet extraction to obtain surface modified silica nanorods; S2: maleic anhydride grafted polypropylene wax is placed in a reaction kettle, melted at 180℃ to obtain a melt, and zinc acetate is added in 3 portions under nitrogen atmosphere to obtain reaction liquid C, wherein the mass ratio of zinc acetate to maleic anhydride grafted polypropylene wax is 6:100, and the reaction is carried out for 1.5h, then vacuumed at-0.086MPa for 45min to remove byproducts, and then cooled and crushed to obtain zinc ionized polypropylene wax; S3: mixing high melt strength polypropylene and metallocene polyethylene with a mass ratio of 80:20 to obtain a base resin, adding surface modified silica nanorods, zinc ionized polypropylene wax and antioxidants to obtain a mixture, wherein the mass ratio of the surface modified silica nanorods to the base resin is 3:100, the mass ratio of the zinc ionized polypropylene wax to the base resin is 5:100, the antioxidants are a mixture of antioxidant 1010 and antioxidant 168 with a mass ratio of 1:1, the mass ratio of the antioxidants to the base resin is 0.4:100; blending the mixture in a twin-screw extruder at 200°C, extruding and granulating to obtain a composite master batch, and vacuum drying the composite master batch at 110°C for 5h to obtain a dried master batch; S4: putting the dried master batch into a single-screw extrusion foaming machine, melting at 210°C and injecting supercritical nitrogen to obtain a melt, wherein the mass ratio of nitrogen to the dried master batch is 1.8:100, the melt is cooled to 168°C in a cooling section, and then extruded and pressure-released to foam to obtain an extrudate, wherein the pressure at the outlet of the machine head is 15MPa, the pressure release rate is 100MPa / s, and the extrudate is shaped and leveled to obtain an ultra-light high-strength polyolefin foaming insulation material for a drone.

[0054] Example 2 The present embodiment provides an ultra-light high-strength polyolefin foaming insulation material for a drone and a preparation method thereof. The preparation method of the ultra-light high-strength polyolefin foaming insulation material for a drone specifically comprises the following steps: S1: adding P123 into a hydrochloric acid solution with a concentration of 1.5M, and adding tetraethyl orthosilicate to obtain a precursor solution, wherein the mass ratio of P123, the hydrochloric acid solution and tetraethyl orthosilicate is 1:85:2.5, stirring and hydrolyzing at 35°C for 20h to obtain a reaction liquid A, increasing the temperature to 90°C and standing for crystallization for 24h, washing and drying to obtain a primary product, increasing the temperature to 550°C at a rate of 1°C / min and calcining for 5h to obtain silica nanorods; preparing a toluene dispersion of the silica nanorods, and adding a mixed modifier to obtain a reaction liquid B, wherein the mass-volume ratio of the silica nanorods to toluene is 1g:20mL, the mixed modifier is composed of hexadecyl triethoxysilane and 3-aminopropyl triethoxysilane at a molar ratio of 1:1, the mass ratio of the mixed modifier to the silica nanorods is 0.3:1, and the reaction is carried out at 105°C for 12h, followed by Soxhlet extraction and vacuum drying to obtain surface modified silica nanorods; S2: putting the maleic anhydride grafted polypropylene wax into a reaction kettle, melting at 170°C to obtain a melt, and adding zinc acetate under a nitrogen atmosphere in two portions to obtain a reaction liquid C, wherein the mass ratio of zinc acetate to the maleic anhydride grafted polypropylene wax is 3:100, vacuumizing at -0.08MPa for 30min after reacting for 1h to remove by-products, and cooling and crushing to obtain zinc ionized polypropylene wax; S3: mixing high melt strength polypropylene and metallocene polyethylene with a mass ratio of 70:30 to obtain a base resin, adding surface modified silica nanorods, zinc ionized polypropylene wax and antioxidants to obtain a mixture, wherein the mass ratio of the surface modified silica nanorods to the base resin is 1:100, the mass ratio of the zinc ionized polypropylene wax to the base resin is 2:100, the antioxidants are a mixture of antioxidant 1010 and antioxidant 168 with a mass ratio of 1:1, the mass ratio of the antioxidants to the base resin is 0.2:100; blending the mixture in a twin-screw extruder at 190°C, extruding and granulating to obtain a composite master batch, and vacuum drying the composite master batch at 100°C for 4h to obtain a dried master batch; S4: putting the dried master batch into a single-screw extrusion foaming machine, melting at 200°C and injecting supercritical nitrogen to obtain a melt, wherein the mass ratio of nitrogen to the dried master batch is 0.5:100, the melt is cooled to 160°C in a cooling section, and then extruded and pressure-released to foam to obtain an extrudate, wherein the pressure at the outlet of the machine head is 10MPa, the pressure release rate is 50MPa / s, and the extrudate is shaped and leveled to obtain an ultra-light high-strength polyolefin foaming insulation material for drones.

[0055] Example 3 The present embodiment provides an ultra-light high-strength polyolefin foaming insulation material for drones and a preparation method thereof. The preparation method of the ultra-light high-strength polyolefin foaming insulation material for drones specifically comprises the following steps: S1: adding P123 into a hydrochloric acid solution with a concentration of 2.0M, and adding tetraethyl orthosilicate to obtain a precursor solution, wherein the mass ratio of P123, the hydrochloric acid solution and tetraethyl orthosilicate is 1:80:2.3, stirring and hydrolyzing at 37°C for 23h to obtain a reaction liquid A, increasing the temperature to 98°C and standing for crystallization for 36h, washing and drying to obtain a primary product, and calcining the primary product at a temperature increasing rate of 1.7°C / min to 570°C for 5.7h to obtain silica nanorods; preparing a toluene dispersion of the silica nanorods, and adding a mixed modifier to obtain a reaction liquid B, wherein the mass-volume ratio of the silica nanorods to toluene is 1g:24mL, the mixed modifier is composed of hexadecyl triethoxysilane and 3-aminopropyl triethoxysilane with a molar ratio of 1.5:1, and the mass ratio of the mixed modifier to the silica nanorods is 0.45:1, and reacting at 107°C for 22h, and vacuum drying after Soxhlet extraction to obtain surface modified silica nanorods; S2: putting the maleic anhydride grafted polypropylene wax into a reaction kettle, melting at 185°C to obtain a melt, and adding zinc acetate under nitrogen atmosphere in 4 times to obtain a reaction liquid C, wherein the mass ratio of zinc acetate to the maleic anhydride grafted polypropylene wax is 5:100, vacuumizing at -0.082MPa for 50min after reacting for 1.7h to remove by-products, and cooling and crushing to obtain zinc ionized polypropylene wax; S3: mixing high melt strength polypropylene and metallocene polyethylene with a mass ratio of 75:25 to obtain a base resin, adding surface modified silica nanorods, zinc ionized polypropylene wax and antioxidants to obtain a mixture, wherein the mass ratio of the surface modified silica nanorods to the base resin is 4:100, the mass ratio of the zinc ionized polypropylene wax to the base resin is 6:100, the antioxidants are a mixture of antioxidant 1010 and antioxidant 168 with a mass ratio of 1:1, the mass ratio of the antioxidants to the base resin is 0.45:100; blending the mixture in a twin-screw extruder at 205°C, extruding and granulating to obtain a composite master batch, and vacuum drying the composite master batch at 115°C for 5.5h to obtain a dried master batch; S4: putting the dried master batch into a single-screw extrusion foaming machine, melting at 215°C and injecting supercritical nitrogen to obtain a melt, wherein the mass ratio of nitrogen to the dried master batch is 1.2:100, the melt is cooled to 172°C in a cooling section, and then extruded and pressure-released to foam to obtain an extrudate, wherein the pressure at the outlet of the machine head is 14MPa, the pressure release rate is 130MPa / s, and the extrudate is shaped and flattened to obtain an ultra-light high-strength polyolefin foaming insulation material for drones.

[0056] Example 4 The present embodiment provides an ultra-light high-strength polyolefin foaming insulation material for drones and a preparation method thereof. The preparation method of the ultra-light high-strength polyolefin foaming insulation material for drones specifically comprises the following steps: S1: adding P123 to a hydrochloric acid solution with a concentration of 2.5M, and adding tetraethyl orthosilicate to obtain a precursor solution, wherein the mass ratio of P123, the hydrochloric acid solution and tetraethyl orthosilicate is 1:65:2.0, stirring and hydrolyzing at 40°C for 24h to obtain reaction liquid A, increasing the temperature to 100°C and standing for crystallization for 48h, washing and drying to obtain a primary product, and calcining the primary product at a temperature increasing rate of 2°C / min to 600°C for 6h to obtain silica nanorods; preparing a toluene dispersion of the silica nanorods, and adding a mixed modifier to obtain reaction liquid B, wherein the mass-volume ratio of the silica nanorods to toluene is 1g:30mL, the mixed modifier is composed of hexadecyl triethoxysilane and 3-aminopropyl triethoxysilane with a molar ratio of 3:1, the mass ratio of the mixed modifier to the silica nanorods is 0.6:1, and the reaction is carried out at 110°C for 24h, followed by Soxhlet extraction and vacuum drying to obtain surface modified silica nanorods; S2: putting the maleic anhydride grafted polypropylene wax into a reaction kettle, melting at 190°C to obtain a melt, and adding zinc acetate three times under a nitrogen atmosphere to obtain reaction liquid C, wherein the mass ratio of zinc acetate to the maleic anhydride grafted polypropylene wax is 8:100, vacuumizing at -0.09MPa for 60min after reacting for 2h to remove by-products, and cooling and crushing to obtain zinc ionized polypropylene wax; S3: mixing high melt strength polypropylene and metallocene polyethylene with a mass ratio of 90:10 to obtain a base resin, adding surface modified silica nanorods, zinc ionized polypropylene wax and antioxidant to obtain a mixture, wherein the mass ratio of surface modified silica nanorods to base resin is 5:100, the mass ratio of zinc ionized polypropylene wax to base resin is 8:100, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 with a mass ratio of 1:1; the mass ratio of antioxidant to base resin is 0.5:100; blending the mixture in a twin-screw extruder at 210°C, extruding and granulating to obtain a composite master batch, and vacuum drying the composite master batch at 120°C for 6h to obtain a dried master batch; S4: putting the dried master batch into a single-screw extrusion foaming machine, melting at 220°C and injecting supercritical nitrogen to obtain a melt, wherein the mass ratio of nitrogen to dried master batch is 2.0:100, the melt is cooled to 175°C in a cooling section, and then extruded and pressure-released to foam to obtain an extrudate, wherein the pressure at the outlet of the machine head is 18MPa, the pressure release rate is 150MPa / s, and the extrudate is shaped and leveled to obtain an ultra-light high-strength polyolefin foaming insulation material for drones.

[0057] Comparative Example 1 This comparative example provides an ultra-light high-strength polyolefin foaming insulation material for drones, which is different from Example 1 in that in S3, surface modified silica nanorods and zinc ionized polypropylene wax are not added, and other operation steps and process parameters are exactly the same as those of Example 1.

[0058] Comparative Example 2 This comparative example provides an ultra-light high-strength polyolefin foaming insulation material for drones, which is different from Example 1 in that in S1, the mixing modifier is omitted, and in S3, silica nanorods are directly used, and other operation steps and process parameters are exactly the same as those of Example 1.

[0059] Comparative Example 3 This comparative example provides an ultra-light high-strength polyolefin foaming insulation material for drones, which is different from Example 1 in that in S1, only hexadecyl triethoxysilane is used without adding 3-aminopropyl triethoxysilane, and other operation steps and process parameters are exactly the same as those of Example 1.

[0060] Comparative Example 4 This comparative example provides an ultra-light high-strength polyolefin foaming insulation material for drones, which is different from Example 1 in that in S3, surface modified silica nanorods are not added, and other operation steps and process parameters are exactly the same as those of Example 1.

[0061] Comparative Example 5 The comparative example provides a super-light high-strength polyolefin foaming insulation material for a drone, which is different from example 1 in that S2 is omitted, and the maleic anhydride grafted polypropylene wax is directly used in S3 to replace the zinc ionized polypropylene wax, and the other operation steps and process parameters are exactly the same as those of example 1.

[0062] The super-light high-strength polyolefin foaming insulation material for a drone of examples 1-4 and comparative examples 1-5 is subjected to performance testing, and the specific process is as follows: The density of the sample is tested according to GB / T 1033.1-2008; The tensile strength of the sample is tested according to GB / T 1040.2-2022; The volume resistivity of the sample is tested according to GB / T 31838.2-2019; The dielectric breakdown strength of the sample is tested according to GB / T 1408.1-2016; The relative dielectric constant of the sample is tested according to GB / T 1409-2006; Torsion performance test: after the prepared super-light high-strength polyolefin foaming insulation material for a drone is made into a cable, a torsion tester is used to test the torsion at a frequency of 60 times / min, a torsion angle of ±180°, and a torsion distance of 500 mm, until the sheath of the cable is broken, and the number of torsions is recorded.

[0063] The test results are shown in Table 1.

[0064] Table 1: Performance test results of the super-light high-strength polyolefin foaming insulation material for a drone of examples 1-4 and comparative examples 1-5 From the test results of example 1 and comparative example 1 in Table 1, in S3, without adding surface modified silica nanorods and zinc ionized polypropylene wax, the melt lacks effective heterogeneous nucleation points and local support networks, and under high foaming ratio, the bubbles are more likely to grow, merge and locally collapse, and the foaming structure is difficult to fully develop, resulting in increased density; the large cell size and poor bubble wall continuity reduce the effective bearing cross section, so the tensile strength decreases, and under repeated torsional load, local stress concentration is more likely to cause crack initiation and propagation, and the number of torsions decreases. Due to the small amount of polar components in the system, the volume resistivity is maintained, but the uneven electric field distribution caused by internal defects and holes reduces the dielectric breakdown strength. Insufficient foaming and high volume fraction of the real phase make the overall relative dielectric constant large.

[0065] From the test results of Example 1 and Comparative Example 2 in Table 1, it can be seen that in S1, the mixing modifier is omitted, and in S3, the silica nanorods are directly used. Although inorganic rigid phase is introduced into the system, due to the strong hydrophilicity of the particle surface and the limited compatibility with the polyolefin matrix, the dispersion in the melt is insufficient, the nucleation is uneven, and local filler-rich areas may also be formed, resulting in limited foaming structure refinement effect and overall density increase. Insufficient interface bonding and the presence of micro-agglomerates weaken the effective load-bearing capacity of the bubble wall, resulting in a decrease in tensile strength and torsional times. The unmodified inorganic surface is more prone to adsorb moisture and ionic impurities, and the interface defects disturb the electric field, resulting in a decrease in volume resistivity and dielectric breakdown strength. Due to insufficient foaming and a high proportion of solid phase, and the introduction of local polarization by the polar interface layer, the relative dielectric constant increases.

[0066] From the test results of Example 1 and Comparative Example 3 in Table 1, it can be seen that in S1, only hexadecyl triethoxysilane is used without adding 3-aminopropyl triethoxysilane, and the hydrophobic long chain on the surface of the nanorods improves its wettability and dispersibility in the polyolefin matrix, and the heterogeneous nucleation effect is more obvious, so the density increases slightly. At the same time, well-dispersed rigid nanorods provide some support to the bubble wall, but due to the lack of -NH2 anchor points provided by 3-aminopropyl triethoxysilane, stable interface association between zinc ionized polypropylene wax and nanorods is difficult to form, and the local network in the melt is incomplete, resulting in slightly inferior bubble wall stability at high foaming ratio, and a slight decrease in tensile strength and torsional life. Due to slightly weaker foaming and network synergy, the dielectric breakdown strength decreases slightly; the overall equivalent polarization capacity increases slightly due to relatively insufficient foaming and a slightly lower gas phase volume fraction, and the relative dielectric constant increases slightly.

[0067] From the test results of Example 1 and Comparative Example 4 in Table 1, it can be seen that in S3, no surface-modified silica nanorods are added, and Zn 2+ -Carboxylate microzones can form certain ionic aggregates in the melt, thereby improving the melt strength, but due to the lack of one-dimensional rigid nanorods providing efficient heterogeneous nucleation and bubble wall skeleton, the bubble refinement and bubble wall toughening effects are limited, and the density increases. The incomplete melt network structure leads to insufficient local load-bearing capacity of the bubble wall, resulting in a decrease in tensile strength and torsional times; the ionized wax has been neutralized, the overall polarity is controlled, and the volume resistivity is maintained, but due to insufficient foaming structure uniformity and interface stability, the dielectric breakdown strength decreases. Due to insufficient foaming and a low gas phase volume fraction, the relative dielectric constant increases.

[0068] From the test results of Example 1 and Comparative Example 5 in Table 1, S2 is omitted, and maleic anhydride grafted polypropylene wax is directly used in S3 instead of zinc ionized polypropylene wax. The system retains more anhydride and carboxyl groups, etc. polar groups, which can act as certain compatibilizers to some extent, improving the interface bonding between the filler and the matrix, but due to the lack of Zn2+ The carboxylate salt local network is difficult to form effective ion cluster physical crosslinking in the melt, the melt strength is limited to improve, the cell stability is insufficient under high foaming conditions, which is manifested as slightly increased density, insufficient cell wall carrying capacity, and decreased tensile strength and torsion times. Unneutralized polar groups are more prone to moisture absorption and participate in polarization under an electric field, resulting in decreased volume resistivity; at the same time, the relative dielectric constant increases due to the increased effective polarization ability caused by the polar phase and adsorbed moisture, and the dielectric breakdown strength decreases.

[0069] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily conceived by those skilled in the art, and all such changes and replacements fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing an ultralight, high-strength polyolefin foamed insulation material for unmanned aerial vehicles (UAVs), characterized in that, The preparation method includes: S1: P123 was added to hydrochloric acid solution, and tetraethyl orthosilicate was added to obtain a precursor solution. The solution was stirred and hydrolyzed to obtain reaction solution A. After heating, the solution was allowed to stand and crystallize, washed, and dried to obtain the initial product. The initial product was calcined to obtain silica nanorods. A toluene dispersion of silica nanorods was prepared, and a mixed modifier was added to obtain reaction solution B. The reaction was carried out, and after Soxhlet extraction, the solution was vacuum dried to obtain surface-modified silica nanorods. S2: Maleic anhydride-grafted polypropylene wax is placed in a reaction vessel and melted to obtain a melt. Zinc acetate is added under a nitrogen atmosphere to obtain reaction solution C. After the reaction, vacuum is applied to remove by-products. After cooling and pulverizing, zinc ionized polypropylene wax is obtained. S3: High melt strength polypropylene and metallocene polyethylene are mixed to obtain a matrix resin. Surface-modified silica nanorods, zinc ionized polypropylene wax and antioxidants are added to obtain a mixture. The mixture is then blended in a twin-screw extruder, extruded and granulated to obtain a composite masterbatch. The composite masterbatch is then vacuum dried to obtain a dried masterbatch. S4: The dried masterbatch is fed into a single-screw extruder foaming machine, melted and injected with supercritical nitrogen to obtain a melt. The melt is cooled in a cooling section, then extruded and depressurized to foam to obtain an extrudate. The extrudate is shaped and leveled to obtain an ultra-lightweight high-strength polyolefin foamed insulation material for UAVs.

2. The method for preparing an ultralight high-strength polyolefin foamed insulation material for unmanned aerial vehicles according to claim 1, characterized in that, In S1: The mass ratio of P123, hydrochloric acid solution, and tetraethyl orthosilicate is 1:(65-85):(2.0-2.5). The reaction solution A is allowed to crystallize at a temperature of 90-100℃.

3. The method for preparing an ultralight high-strength polyolefin foamed insulation material for unmanned aerial vehicles according to claim 1, characterized in that, In S1: The mass-to-volume ratio of the silica nanorods to toluene is 1g:(20-30)mL; The molar ratio of hexadecyltriethoxysilane to 3-aminopropyltriethoxysilane in the mixed modifier is (1-3):1; The mass ratio of the mixed modifier to the silica nanorods is (0.3-0.6):

1.

4. The method for preparing an ultralight high-strength polyolefin foamed insulation material for unmanned aerial vehicles according to claim 1, characterized in that, In S2: The zinc acetate is added to the melt in 2-4 portions; The mass ratio of zinc acetate to maleic anhydride-grafted polypropylene wax is (3-8):

100.

5. The method for preparing an ultralight high-strength polyolefin foamed insulation material for unmanned aerial vehicles according to claim 1, characterized in that, In S3: The mass ratio of the high melt strength polypropylene to the metallocene polyethylene is (70-90):(30-10); The mass ratio of the surface-modified silica nanorods to the matrix resin is (1-5):100; The mass ratio of the zinc ionized polypropylene wax to the matrix resin is (2-8):

100.

6. The method for preparing an ultralight high-strength polyolefin foamed insulation material for unmanned aerial vehicles according to claim 1, characterized in that, In S3: The antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1. The mass ratio of the antioxidant to the matrix resin is (0.2-0.5):

100.

7. The method for preparing an ultralight high-strength polyolefin foamed insulation material for unmanned aerial vehicles according to claim 1, characterized in that, In S4: The melting temperature of the dried masterbatch is 200-220℃; The mass ratio of nitrogen to dried masterbatch is (0.5-2.0):

100.

8. The method for preparing an ultralight high-strength polyolefin foamed insulation material for unmanned aerial vehicles according to claim 1, characterized in that, In S4: The melt is cooled to 160-175°C in a cooling section; The pressure at the die head outlet of the single-screw extruder foaming machine is 10-18 MPa; The rate of pressure release is 50-150 MPa / s.

9. A lightweight, high-strength polyolefin foamed insulation material for unmanned aerial vehicles (UAVs), characterized in that, It is prepared according to any one of claims 1-8.

10. A cable, characterized in that, A conductive material coated with an ultralight high-strength polyolefin foamed insulating material for unmanned aerial vehicles was prepared using the preparation method according to any one of claims 1-8.

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