Blending modified material with wave-absorbing shielding function and preparation process

Abstract

The application belongs to the technical field of high polymers, and particularly relates to a blended modified material with wave-absorbing shielding function and a preparation process. The blended modified material with wave-absorbing shielding function comprises the following raw materials in parts by mass: PBT 55-75 parts, modified nanocellulose aerogel 10-20 parts, norbornene type cyclic olefin copolymer 5-15 parts, toughening agent 2-7 parts, lubricant 1-3 parts, antioxidant 0.5-2 parts, and porous polystyrene microspheres 0.5-1 part. The application provides a blended modified material with wave-absorbing shielding function and a preparation process. The blended modified material provided by the application has excellent wave-absorbing shielding performance at 77GHz, excellent Izod notched impact strength and excellent chemical resistance, and can be applied to a vehicle-mounted millimeter wave radar cover.

Description

Technical Field

[0001] This invention belongs to the field of polymer technology, specifically relating to blended modified materials with wave absorption and shielding functions and their preparation process. Background Technology

[0002] In recent years, intelligent driving and driver assistance technologies have been continuously developing in the automotive field and are becoming integrated into people's lives. Radar is an indispensable sensor in these systems. However, the increasing number of radars and their mutual interference can affect their normal operation.

[0003] The radar radome is a critical component for protecting the radar. It also needs to have radar-absorbing and shielding properties to reduce electromagnetic interference and improve the accuracy and reliability of the radar. In addition, it also needs to have good chemical resistance and impact resistance.

[0004] Chinese Patent CN117801494A discloses a radar-absorbing material for automotive radar and its preparation method. The material comprises the following raw materials in the following mass ratio: 50-80 parts polycarbonate resin, 3-20 parts toughening agent, 5-30 parts radar-absorbing filler, 10-20 parts fiber, 0.1-3 parts flame retardant, 0.1-1 part light stabilizer, 0.3-2 parts lubricant, and 0.3-2 parts antioxidant. The above components are mixed and melt-blended in a twin-screw extruder, then extruded and granulated. The granules are dried and then melted, cooled, shaped, drawn, and cut in a single-screw extruder to obtain sheet materials or semi-circular dome products. The radar-absorbing material provided by this invention has advantages such as high absorption efficiency, flame retardancy, and high temperature resistance, making it suitable for automotive millimeter-wave radar domes. However, the impact resistance and radar absorption performance of this technical solution need improvement, and its chemical resistance has not been addressed.

[0005] Chinese Patent Publication No. CN 116829635 A discloses a composite material comprising: about 50 wt% to about 99 wt% of a thermoplastic resin, wherein the thermoplastic resin includes polyester; and about 0.1 wt% to 15 wt% of carbon fiber filler, wherein the carbon fibers have a bulk density of at least 500 g / L and a volume resistivity of less than 2,000 μΩ·cm, and the length-to-diameter ratio of a single filament is at least 300. A 3.175 mm thick molded sample of the composite material exhibits a transmittance of less than 15% of incident microwave radiation when measured at frequencies from 75 to 110 GHz using the free-space method. The combined weight percentage of all components does not exceed 100 wt%, and all weight percentage values ​​are based on the total weight of the composite material. However, this technical solution does not address its chemical resistance. Summary of the Invention

[0006] The present invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial solution. Specifically, the present invention provides a blended modified material with wave-absorbing and shielding functions and a preparation process. The blended modified material provided by the present invention has excellent wave-absorbing and shielding performance at 77 GHz, as well as excellent cantilever beam notched impact strength and chemical resistance, and can be applied to vehicle-mounted millimeter-wave radar domes.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a blended modified material with wave-absorbing and shielding functions, comprising the following raw materials in parts by weight: 55-75 parts of PBT, 10-20 parts of modified nanocellulose aerogel, 5-15 parts of norbornene-type cyclic olefin copolymer, 2-7 parts of toughening agent, 1-3 parts of lubricant, 0.5-2 parts of antioxidant, and 0.5-1 parts of porous polystyrene microspheres.

[0009] In some preferred embodiments, the PBT is selected from at least one of Toraycon™ 5201-X11, Toraycon™ 5201-X10, and Toraycon™ 8207X01 B.

[0010] In some preferred embodiments, the modifiers of the modified nanocellulose aerogel include helical multi-walled carbon nanotubes, cubic silicon carbide whiskers, and hexagonal boron nitride.

[0011] Preferably, the mass ratio of the spiral multi-walled carbon nanotubes, cubic silicon carbide whiskers and hexagonal boron nitride is 0.5-0.8:0.2-0.5:1-3.

[0012] In some preferred embodiments, the helical multi-walled carbon nanotubes contain 60-80 wt% helical multi-walled carbon nanotubes.

[0013] Preferably, the diameter of the helical multi-walled carbon nanotube is 100-200 nm.

[0014] In some preferred embodiments, the cubic silicon carbide whiskers have a diameter of 100-600 nm and a length of 10-50 μm.

[0015] In some preferred embodiments, the particle size of the hexagonal boron nitride is 1-5 μm.

[0016] Preferably, the preparation method of the modified nanocellulose aerogel includes the following steps: dispersing nanocellulose in an alkaline solution, adding a modifier, stirring to obtain a suspension; adding a crosslinking agent to the suspension and continuing to stir and react to obtain a hydrogel; removing impurities and then freeze-drying to obtain the modified nanocellulose aerogel.

[0017] Preferably, the preparation method of the modified nanocellulose aerogel includes the following steps: dispersing nanocellulose in an alkaline solution, adding a modifier under ice bath conditions, stirring at 300-500 rpm for 30-40 min to obtain a suspension; adding a crosslinking agent to the suspension and stirring for another 10-20 min, reacting at 25°C for 8-12 h to obtain a hydrogel; removing impurities and freeze-drying at -90°C to -50°C for 40-50 h to obtain the modified nanocellulose aerogel.

[0018] Preferably, the nanocellulose has a fiber diameter of 10-30 nm and a fiber length of 4-10 μm.

[0019] Preferably, the alkaline solution is sodium hydroxide, urea and water in a mass ratio of 5-10:10-15:75-85.

[0020] Preferably, the mass ratio of the nanocellulose, alkaline solution, modifier and crosslinking agent is 5-10:100:1.7-4.3:1-2.

[0021] Preferably, the crosslinking agent is N,N-methylenebisacrylamide.

[0022] This invention modifies nanocellulose using helical multi-walled carbon nanotubes, cubic silicon carbide whiskers, and hexagonal boron nitride. With cellulose as the basic framework and helical multi-walled carbon nanotubes, cubic silicon carbide whiskers, and hexagonal boron nitride as reinforcing frameworks, the resulting multi-network structure of cellulose aerogel not only optimizes the electromagnetic wave reflection path, extends the propagation path, and reduces electromagnetic wave energy, thus improving the wave absorption and shielding of the blended modified material, but also works together with porous polystyrene microspheres to resist impact, chemical penetration and erosion, and enhance its toughness and chemical resistance.

[0023] Preferably, the modifier is a polydopamine surface-modified modifier.

[0024] Preferably, the preparation method of the polydopamine surface-modified modifier includes the following steps: mixing the modifier and Tris-HCl buffer, stirring evenly, adding dopamine hydrochloride, continuing to stir, filtering, washing, and drying after stirring to obtain the final product.

[0025] Preferably, the preparation method of the polydopamine surface-modified modifier includes the following steps: mixing the modifier and Tris-HCl buffer, stirring evenly at 500-1000 rpm under 30°C, adding dopamine hydrochloride, continuing to stir for 3-6 hours, filtering, washing, and drying after stirring to obtain the final product.

[0026] Preferably, the pH of the Tris-HCl buffer solution is 8.5.

[0027] Preferably, the ratio of the modifier, Tris-HCl buffer, and dopamine hydrochloride is 1-1.5g: 10-15mL: 0.1-0.15g.

[0028] This invention modifies the surface of a modifier with polydopamine, which avoids the aggregation of the modifier and allows it to bond with nanofibers through hydrogen bonds, thereby forming a dense cross-linked network aerogel that enhances its toughness. In addition, the modifier with polydopamine surface modification can also bond with porous polystyrene microspheres through hydrogen bonds, thereby enhancing the wave absorption shielding function, toughness and chemical resistance of the blended modified material.

[0029] In some preferred embodiments, the norbornene-type cyclic olefin copolymer is selected from APEL™ APL6513T and / or APEL™ APL6515T.

[0030] Another key technical solution of the present invention lies in the addition of norbornene-type cyclic olefin copolymer. During the experiment, the inventors unexpectedly discovered that the addition of norbornene-type cyclic olefin copolymer significantly enhanced the wave absorption shielding function, toughness and chemical resistance of the blended modified material.

[0031] In some preferred embodiments, the toughening agent is selected from glycidyl methacrylate-grafted ethylene-methyl acrylate copolymer and / or ethylene-glycidyl methacrylate copolymer.

[0032] In some preferred embodiments, the lubricant is selected from at least one of pentaerythritol ester, polyethylene wax, oxidized polyethylene wax, and ethylene bis-stearamide.

[0033] In some preferred embodiments, the antioxidant is selected from hindered phenols and / or phosphites.

[0034] In some preferred embodiments, the porous polystyrene microspheres are hydroxyl-containing porous polystyrene microspheres.

[0035] Preferably, the particle size of the hydroxyl porous polystyrene microspheres is 2-5 µm.

[0036] Secondly, the present invention provides a preparation process for a blended modified material with wave-absorbing and shielding functions, comprising the following steps: PBT, modified nanocellulose aerogel, norbornene-type cyclic olefin copolymer, toughening agent, lubricant, antioxidant and porous polystyrene microspheres are mixed evenly and then melt-extruded and granulated by a twin-screw extruder to obtain the final product.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. This invention uses helical multi-walled carbon nanotubes, cubic silicon carbide whiskers, and hexagonal boron nitride to modify nanocellulose. With cellulose as the basic framework and helical multi-walled carbon nanotubes, cubic silicon carbide whiskers, and hexagonal boron nitride as the reinforcing framework, the resulting multi-network structure of cellulose aerogel not only optimizes the electromagnetic wave reflection path, extends the propagation path, and reduces electromagnetic wave energy, thus improving the wave absorption and shielding of the blended modified material, but also works together with porous polystyrene microspheres to resist the penetration and erosion of chemicals, enhancing its toughness and chemical resistance.

[0039] 2. This invention modifies the surface of a modifier with polydopamine to form a dense cross-linked network aerogel, which works together with porous polystyrene microspheres to enhance the wave absorption shielding function, toughness and chemical resistance of the blended modified material.

[0040] 3. By adding norbornene-type cyclic olefin copolymers, this invention significantly enhances the microwave absorption shielding function, toughness, and chemical resistance of the blended modified materials. Attached Figure Description

[0041] Figure 1 Here is a SEM image of the modified nanocellulose aerogel A of this invention;

[0042] Figure 2 Here is a SEM image of the modified nanocellulose aerogel F of this invention;

[0043] Figure 3 This is a physical image of the blended modified material with wave-absorbing and shielding function according to Embodiment 1 of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0045] Unless otherwise specified, the raw materials, reagents or apparatus used in the following examples and comparative examples are available from conventional commercial sources or can be obtained by existing known methods.

[0046] Modified nanocellulose aerogel A:

[0047] The preparation method includes the following steps: dispersing nanocellulose in an alkaline solution, adding a modifier under ice bath conditions, stirring at 400 rpm for 30 min to obtain a suspension; adding a crosslinking agent to the suspension and stirring for another 20 min, reacting at 25℃ for 12 h to obtain a hydrogel; removing impurities and freeze-drying at -80℃ for 48 h to obtain modified nanocellulose aerogel.

[0048] The nanocellulose has a fiber diameter of 10-30 nm and a fiber length of 5 μm. Model: Nanjing Tianlu Nanotechnology Co., Ltd., Model: TL-016.

[0049] The alkaline solution is sodium hydroxide, urea and water in a mass ratio of 8:12:80.

[0050] The modifier is a combination of helical multi-walled carbon nanotubes, cubic silicon carbide whiskers, and hexagonal boron nitride in a mass ratio of 0.7:0.3:2.

[0051] The spiral multi-walled carbon nanotubes contain 60wt% spiral multi-walled carbon nanotubes with a diameter of 100-200nm. Nanjing Jicang Nanotechnology Co., Ltd., model: JCHMT-90-150-6.

[0052] The cubic silicon carbide whiskers have a diameter of 100-600 nm and a length of 10-50 μm. (Qinhuangdao Yinuo High-Tech Materials Development Co., Ltd., Model: SF-1)

[0053] The hexagonal boron nitride has a particle size of 5 μm, manufactured by Xi'an Bona Materials Technology Co., Ltd., model number: BN-BN-004.

[0054] The crosslinking agent is N,N-methylenebisacrylamide.

[0055] The mass ratio of the nanocellulose, alkaline solution, modifier, and crosslinking agent is 8:100:3:1.2.

[0056] The modifier is a polydopamine surface-modified modifier. The preparation method includes the following steps: the modifier and Tris-HCl buffer (pH 8.5) are mixed and stirred evenly at 800 rpm at 30°C. Dopamine hydrochloride is added and stirring is continued for 5 hours. After stirring, the mixture is filtered, washed, and dried to obtain the final product.

[0057] The ratio of the modifier, Tris-HCl buffer, and dopamine hydrochloride was 1.2 g: 12 mL: 0.12 g.

[0058] Modified nanocellulose aerogel B:

[0059] The only difference between this and modified nanocellulose aerogel A is that the helical multi-walled carbon nanotubes are replaced with multi-walled carbon nanotubes of equal mass, wherein the diameter of the multi-walled carbon nanotubes is >50nm. (Nanjing Jicang Nanotechnology Co., Ltd., Model: JCMT-95-50-10); all other aspects are the same.

[0060] Modified nanocellulose aerogel C:

[0061] The only difference from modified nanocellulose aerogel A is that cubic silicon carbide whiskers are replaced with carbon nanotube whiskers of equal mass, wherein the diameter of the carbon nanotube whiskers is 80-150nm. Nanjing Jicang Nanotechnology Co., Ltd., model: JCGMT-999-115-7; all other aspects are the same.

[0062] Modified nanocellulose aerogel D:

[0063] The only difference from modified nanocellulose aerogel A is that cubic silicon carbide whiskers are replaced with an equal mass of cubic silicon carbide with a particle size of 500 nm. (Qinhuangdao Yinuo High-tech Materials Development Co., Ltd.)

[0064] Modified nanocellulose aerogel E:

[0065] The only difference from modified nanocellulose aerogel A is that hexagonal boron nitride is replaced with an equal mass of multi-walled carbon nanotubes, the diameter of which is >50nm. (Nanjing Jicang Nanotechnology Co., Ltd., Model: JCMT-95-50-10); all other aspects are the same.

[0066] Modified nanocellulose aerogel F:

[0067] The only difference between this and modified nanocellulose aerogel A is that the modifier does not undergo polydopamine surface modification; otherwise, they are the same.

[0068] SEM images of modified nanocellulose aerogel A and modified nanocellulose aerogel F are shown below. Figure 1 and Figure 2 As shown, Figure 1 It can be seen that the modified nanocellulose aerogel A has a uniform, dense, and well-structured network; while from Figure 2 It can be seen that the modified nanocellulose aerogel F exhibited aggregation.

[0069] Example 1

[0070] The blended modified material with wave absorption and shielding function includes the following raw materials in parts by weight: 65 parts PBT, 15 parts modified nanocellulose aerogel A, 10 parts norbornene-type cyclic olefin copolymer, 5 parts toughening agent, 2 parts lubricant, 1 part antioxidant, and 0.7 parts porous polystyrene microspheres.

[0071] The PBT is Toraycon™ 5201-X11.

[0072] The norbornene-type cyclic olefin copolymer is APEL™ APL6513T.

[0073] The toughening agent is LOTADER® AX8900, which is a copolymer of glycidyl methacrylate grafted with ethylene-methyl acrylate.

[0074] The lubricant is pentaerythritol ester.

[0075] The antioxidant is antioxidant 1010.

[0076] The porous polystyrene microspheres are hydroxyl-containing porous polystyrene microspheres with a particle size of 2-5µm, manufactured by Beijing Zhongke Keyou Technology Co., Ltd.

[0077] The preparation process of the above-mentioned blended modified material with wave absorption and shielding function includes the following steps: PBT, modified nanocellulose aerogel, norbornene-type cyclic olefin copolymer, toughening agent, lubricant, antioxidant and porous polystyrene microspheres are mixed evenly and then melt-extruded and granulated by twin-screw extruder to obtain the final product.

[0078] Example 2

[0079] The only difference from Example 1 is that the modified nanocellulose aerogel A is replaced with the same mass of modified nanocellulose aerogel B; all other aspects are the same.

[0080] Example 3

[0081] The only difference from Example 1 is that the modified nanocellulose aerogel A is replaced with the same mass of modified nanocellulose aerogel C; all other aspects are the same.

[0082] Example 4

[0083] The only difference from Example 1 is that the modified nanocellulose aerogel A is replaced with the same mass of modified nanocellulose aerogel D; all other aspects are the same.

[0084] Example 5

[0085] The only difference from Example 1 is that the modified nanocellulose aerogel A is replaced with an equal mass of modified nanocellulose aerogel E; all other aspects are the same.

[0086] Example 6

[0087] The only difference from Example 1 is that the modified nanocellulose aerogel A is replaced with the same mass of modified nanocellulose aerogel F; all other aspects are the same.

[0088] Comparative Example 1

[0089] The only difference from Example 1 is that the norbornene-type cyclic olefin copolymer is replaced with an equal mass of glycidyl methacrylate-grafted ethylene-methyl acrylate copolymer, LOTADER® AX890; all other aspects are the same.

[0090] Comparative Example 2

[0091] The only difference from Example 1 is that the toughening agent is replaced with an equal mass of norbornene-type cyclic olefin copolymer; all other aspects are the same.

[0092] Comparative Example 3

[0093] The only difference from Example 1 is that the porous polystyrene microspheres are replaced with hollow glass microspheres of the same mass. The hollow glass microspheres have a D50 of 13µm and a true density of 0.63-0.67g / cm³. They are from Zhengzhou Shenglait Hollow Microsphere New Material Co., Ltd., model: HS65. All other aspects are the same.

[0094] The blended modified materials with wave-absorbing and shielding functions of Examples 1-6 and Comparative Examples 1-3 were injection molded into test samples with a size of 3.0*100*100mm, and the following performance tests were conducted.

[0095] Performance Test 1:

[0096] (1) Electromagnetic shielding effectiveness: The electromagnetic shielding effectiveness at 77 GHz was tested using the free space method;

[0097] (2) Reflectivity and absorptivity: The reflectivity and absorptivity at 77 GHz were tested using the free-space method;

[0098] (3) Notched impact strength of cantilever beam: tested in accordance with ISO 180 standard;

[0099] (4) Chemical resistance: Tested according to IEC 61300-2-34: The sample to be tested was completely immersed in the chemical solvent. After soaking, it was wiped dry and the mass loss rate was calculated. The results are shown in Table 1.

[0100] Table 1. Performance test results of the blended modified materials with wave-absorbing and shielding functions in Examples 1-6 and Comparative Examples 1-3.

[0101]

[0102] As can be seen from Table 1, compared with Example 1, in the modified nanocellulose aerogel B of Example 2, the spiral multi-walled carbon nanotubes were replaced with the same mass of multi-walled carbon nanotubes, and in the modified nanocellulose aerogel C of Example 3, the cubic silicon carbide whiskers were replaced with the same mass of carbon nanotube whiskers. The resulting blended modified materials showed little change in wave absorption and shielding performance, but the notched impact strength of the cantilever beam and the chemical resistance decreased significantly.

[0103] Compared with Example 1, in the modified nanocellulose aerogel D of Example 4, cubic silicon carbide whiskers were replaced with an equal mass of cubic silicon carbide; in the modified nanocellulose aerogel E of Example 5, hexagonal boron nitride was replaced with an equal mass of multi-walled carbon nanotubes; and in Example 6, the modifier was not modified with polydopamine. The resulting blended modified materials showed a significant decrease in wave absorption and shielding performance, as well as a significant decrease in cantilever beam notched impact strength and chemical resistance.

[0104] Compared with Example 1, Comparative Example 1 replaced the norbornene-type cyclic olefin copolymer with an equal mass of glycidyl methacrylate-grafted ethylene-methyl acrylate copolymer. The resulting blended modified material showed a significant decrease in wave absorption and shielding performance, as well as a significant decrease in cantilever beam notched impact strength and chemical resistance.

[0105] Compared with Example 1, Comparative Example 2 replaced the toughening agent with an equal mass of norbornene-type cyclic olefin copolymer. The resulting blended modified material showed little change in microwave shielding performance, but the notched impact strength and chemical resistance of the cantilever beam decreased significantly.

[0106] Compared with Example 1, Comparative Example 3 replaced porous polystyrene microspheres with hollow glass microspheres of the same mass. The resulting blended modified material showed a significant decrease in wave absorption and shielding performance, as well as a significant decrease in cantilever beam notched impact strength and chemical resistance.

[0107] Performance Test 2

[0108] The blended modified material with microwave absorption and shielding function of Example 1 was sent to an external testing facility to measure its SVHC concentration. The results are shown in Table 2.

[0109] Table 2. SVHC concentration detection results of the blended modified material with microwave absorbing and shielding function in Example 1.

[0110]

[0111] Note: Not detected: less than the detection limit.

[0112] Performance Test 3

[0113] The blended modified material with wave-absorbing and shielding function of Example 1 was sent to an external testing facility to measure the concentrations of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers, phthalates, and polycyclic aromatic hydrocarbons. The results are shown in Tables 3-5.

[0114] Table 3. Concentration test results of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls (PBBBs), and polybrominated diphenyl ethers (PBDEs) in the blended modified material with microwave shielding function of Example 1 (unit: mg / kg)

[0115]

[0116] Note: (1) "-" = not specified;

[0117] (2) The maximum permissible limits refer to the requirements of Annex II of RoHS 2011 / 65 / EU and the revised Directive (EU) 2015 / 863.

[0118] Table 4. Phthalate concentration test results of the blended modified material with wave-absorbing and shielding function in Example 1 (unit: mg / kg)

[0119]

[0120] Table 5. Polycyclic aromatic hydrocarbon concentration test results of the blended modified material with microwave shielding function in Example 1 (unit: mg / kg)

[0121]

[0122] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A blended modified material with wave-absorbing shielding function, characterized in that, The raw materials include the following quality parts: PBT 55-75 parts, modified nanocellulose aerogel 10-20 parts, norbornene type cyclic olefin copolymer 5-15 parts, toughening agent 2-7 parts, lubricant 1-3 parts, antioxidant 0.5-2 parts, porous polystyrene microspheres 0.5-1 part; The modifier of the modified nanocellulose aerogel includes helical multi-walled carbon nanotubes, cubic silicon carbide whiskers and hexagonal boron nitride; The modifier is a polydopamine surface modified modifier; The toughening agent is selected from glycidyl methacrylate grafted ethylene-methyl acrylate copolymer and / or ethylene-glycidyl methacrylate copolymer.

2. The blended modified material with wave-absorbing shielding function according to claim 1, characterized in that, The PBT is selected from at least one of Toraycon™ 5201-X11, Toraycon™ 5201-X10 and Toraycon™ 8207X01 B.

3. The blended modified material with wave-absorbing shielding function according to claim 2, characterized in that, The helical multi-walled carbon nanotubes contain 60-80wt% helical multi-walled carbon nanotubes; the diameter of the helical multi-walled carbon nanotubes is 100-200nm; the diameter of the cubic silicon carbide whiskers is 100-600nm, and the length is 10-50μm; the particle size of the hexagonal boron nitride is 1-5μm.

4. The blended modified material with wave-absorbing shielding function according to claim 3, characterized in that, The preparation method of the modified nanocellulose aerogel includes the following steps: Disperse nanocellulose in an alkali solution, add a modifier, stir to obtain a suspension; add a crosslinking agent to the suspension and continue to stir, react to obtain a hydrogel, remove impurities, and then freeze-dry to obtain the modified nanocellulose aerogel. 5.The blended modified material with wave-absorbing shielding function of claim 1, wherein, The preparation method of the polydopamine surface modified modifier includes the following steps: Mix the modifier and Tris-HCl buffer, stir uniformly, add dopamine hydrochloride, continue to stir, filter, wash and dry after stirring to obtain the polydopamine surface modified modifier. 6.The blended modified material with wave-absorbing shielding function of claim 1, wherein, The norbornene type cyclic olefin copolymer is selected from APEL™ APL6513T and / or APEL™ APL6515T. 7.The blended modified material with wave-absorbing shielding function of claim 1, wherein, The porous polystyrene microspheres are hydroxyl porous polystyrene microspheres; the particle size of the hydroxyl porous polystyrene microspheres is 2-5µm.

8. The process for preparing the blend-modified material with wave-absorbing shielding function according to any one of claims 1-7, characterized in that, The method includes the following steps: Mix PBT, modified nanocellulose aerogel, norbornene type cyclic olefin copolymer, toughening agent, lubricant, antioxidant and porous polystyrene microspheres uniformly, melt extrude and granulate through a double screw extruder to obtain the granules.

Images