Cornflower-shaped polyaniline modified carbon cloth base material, electromagnetic shielding polyurethane foam as well as preparation method and application of electromagnetic shielding polyurethane foam

Abstract

The invention provides a cornflower-shaped polyaniline modified carbon cloth base material, electromagnetic shielding polyurethane foam as well as a preparation method and application of the cornflower-shaped polyaniline modified carbon cloth base material and the electromagnetic shielding polyurethane foam. The cornflower-shaped polyaniline modified carbon cloth base material is prepared from the following components in parts by weight: 20 to 40 parts by weight of cornflower-shaped polyaniline, 30 to 50 parts by weight of carbon fiber cloth, 0.3 to 1.6 parts by weight of a heat stabilizer and 0.2 to 0.6 part by weight of an antioxidant. When the cornflower-shaped polyaniline modified carbon cloth base material is used for preparing the electromagnetic shielding polyurethane foam, the electromagnetic shielding performance of the polyurethane foam can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a cornflower-shaped polyaniline modified carbon cloth substrate, electromagnetic shielding polyurethane foam, and a preparation method and application thereof. Background Art

[0002] In the era of rapid development of modern electronic technology, electromagnetic interference (EMI) problems are becoming increasingly serious, and the demand for high-performance electromagnetic shielding materials is becoming more urgent. From the circuits inside electronic devices to external communication base stations, electromagnetic radiation not only affects the normal operation of the equipment, but also poses a potential threat to human health. Therefore, the development of efficient, stable and easy-to-process electromagnetic shielding materials has become an important research direction in the field of materials science.

[0003] At present, the electromagnetic shielding materials on the market mainly include metal shielding materials, absorbing materials and conductive polymers. Among them, metal shielding materials (such as copper, aluminum, nickel, etc.) have excellent conductivity and electromagnetic shielding performance, but they have problems such as large mass, high processing difficulty, easy corrosion, etc., and are not suitable for lightweight and flexible applications. Absorbing materials (such as ferrites and carbon-based materials) achieve shielding effects by absorbing electromagnetic waves, but often have problems such as narrow absorbing bandwidth and complex composite processes. Conductive polymers, such as polyaniline (PANI) and polypyrrole (PPy), have become a research hotspot in the field of electromagnetic shielding in recent years because of their light weight, good environmental stability and strong controllability.

[0004] Polyaniline has become one of the important candidates for electromagnetic shielding materials due to its excellent conductivity and chemical stability. Through doping or modification, the electrical properties of polyaniline can be adjusted and can be used in the shielding layer of flexible electronic devices. However, traditional polyaniline materials still have the following problems: (1) The microstructure is difficult to accurately control, resulting in unstable shielding performance; (2) The interface bonding force is weak and the composite stability with the substrate is poor; (3) The processing method is complicated and difficult to meet the needs of practical applications. Therefore, how to optimize the microstructure of polyaniline, improve the shielding performance, and achieve stable and easy-to-process composite materials is an important direction of current research.

[0005] In order to improve the shielding performance and processability of polyaniline, a variety of different morphology control strategies have been developed at home and abroad, such as template method, electrospinning method, chemical oxidation polymerization method, etc. However, these methods often have complex synthesis steps and are difficult to scale up. In recent years, polyaniline with special morphology has attracted the attention of researchers due to its unique multi-level and multi-branched nanostructure. This morphology can increase the interface polarization and multiple reflections inside the material, improve impedance matching, thereby optimizing the absorption and reflection balance of electromagnetic waves and enhancing the electromagnetic shielding effect. However, there are still few synthesis methods for the template-free synthesis of polyaniline with special morphology, and there are problems such as difficulty in stable morphology control and low yield.

[0006] On the other hand, carbon cloth has attracted much attention in the field of electromagnetic shielding composite materials due to its excellent conductivity, flexibility and mechanical stability. The conductive network inside the carbon cloth can effectively improve the overall conductivity of the material, promote charge transfer, and enhance the loss of electromagnetic waves. The composite of polyaniline and carbon cloth can combine the advantages of both and achieve a highly efficient electromagnetic shielding effect. However, existing polyaniline / carbon cloth composites still face the following challenges: (1) It is difficult to achieve uniform loading of polyaniline on the surface of carbon cloth, which affects the stability of the shielding material; (2) The interface compatibility between the two is poor, which easily leads to phase separation and reduces the conductivity and mechanical properties of the material; (3) The existing composite process is complex and difficult to apply on a large scale.

[0007] In addition, in order to further improve the lightweight and structural stability of electromagnetic shielding composite materials, researchers have proposed a strategy to prepare conductive polymer / carbon cloth composite foams through foaming technology. Polyurethane foam is widely used in wave absorption and electromagnetic shielding applications due to its light weight, excellent mechanical properties and controllable pore structure. However, the electromagnetic shielding efficiency of ordinary polyurethane foam is low and cannot meet the needs of high-performance applications. Therefore, by introducing high-efficiency electromagnetic shielding fillers into polyurethane foam, such as polyaniline-modified carbon cloth substrates, its shielding performance can be effectively improved while maintaining the flexibility and mechanical stability of the foam.

[0008] At present, there are still some key challenges in the preparation process of conductive polymer composite foam: (1) How to ensure the stable loading of polyaniline on carbon cloth and improve the interfacial bonding strength; (2) How to optimize the compatibility of carbon cloth with polyurethane matrix after modification to prevent stratification or phase separation; (3) How to ensure the uniform distribution of polyaniline modified carbon cloth through a reasonable foaming process to improve the electromagnetic shielding performance.

[0009] At present, there are still many technical challenges in the preparation of polyaniline / polyurethane foam with high electromagnetic shielding performance, including precise control of the microscopic morphology of polyaniline, effective compounding with carbon cloth, and stable construction of water-oil two-phase system. These challenges limit the application of electromagnetic shielding materials in high-end electronic equipment, electromagnetic interference protection and new flexible electronic devices. Therefore, an innovative preparation method is urgently needed to promote the development of the field of electromagnetic shielding materials and meet the demand of modern electronic technology for high-performance electromagnetic shielding materials. Summary of the invention

[0010] The electromagnetic shielding performance of traditional polyurethane foam is low and it is difficult to meet the requirements of high-performance shielding. How to improve its conductivity and structural stability is still an urgent problem to be solved. The present invention aims to solve one of the technical problems in the related art at least to a certain extent. The present invention provides a cornflower-shaped polyaniline modified carbon cloth substrate and a method for preparing its electromagnetic shielding polyurethane foam to solve the problem in the prior art that the microscopic morphology of polyaniline is difficult to accurately control, resulting in limited electromagnetic shielding performance; thereby breaking through the bottleneck of poor compatibility and severe phase separation in the composite process of polyaniline and carbon cloth, so as to give full play to the synergistic effect of the two.

[0011] Specifically, the present invention provides the following technical solutions:

[0012] In a first aspect of the present invention, a cornflower-shaped polyaniline-modified carbon cloth substrate is provided, comprising, in parts by weight:

[0013] 20-40 parts by weight of cornflower-shaped polyaniline,

[0014] 30-50 parts by weight of carbon fiber cloth,

[0015] Heat stabilizer 0.3-1.6 parts by weight,

[0016] and 0.2-0.6 parts by weight of antioxidant.

[0017] According to an embodiment of the present invention, the cornflower-shaped polyaniline modified carbon cloth substrate may also include the following technical features:

[0018] According to an embodiment of the present invention, the thickness of the cornflower-shaped polyaniline modified carbon cloth substrate is 0.1-0.2 mm.

[0019] According to an embodiment of the present invention, the heat stabilizer is selected from at least one of triphenyl phosphite, tris(2,6-dimethylphenyl) phosphite, and trimethyl phosphate.

[0020] According to an embodiment of the present invention, the antioxidant is selected from at least one of tris(nonylphenyl) phosphite, distearyl thiopropionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,5-di-tert-butyl-hydroxyphenyl propionate octadecyl alcohol or 2,2-methylenebis(4-methyl-6-tert-butylphenol).

[0021] According to an embodiment of the present invention, the cornflower-shaped polyaniline is prepared by using the following raw materials in parts by weight:

[0022] 6-10 parts by weight of aniline, 3-5 parts by weight of chiral doping acid, 0.1-0.5 parts by weight of oil phase solvent, 0.5-2 parts by weight of aniline oligomer, 20-50 parts by weight of water phase solvent, 1-5 parts by weight of initiator, and 0.1-0.5 parts by weight of interface stabilizer.

[0023] According to an embodiment of the present invention, the chiral doping acid is selected from at least one of (R)-(+)-camphorsulfonic acid, (S)-(-)-camphorsulfonic acid, (R)-(-)-malic acid, and (S)-(+)-tartaric acid.

[0024] According to an embodiment of the present invention, the oil phase solvent is selected from at least one of chloroform, dichloromethane, carbon tetrachloride, toluene, xylene, and n-hexane.

[0025] According to an embodiment of the present invention, the aniline oligomer is selected from at least one of N-phenyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, and N-methyl-N-phenyl-p-phenylenediamine.

[0026] According to an embodiment of the present invention, the aqueous phase solvent is selected from one of deionized water, ethanol, propanol, ethylene glycol, and acetone;

[0027] According to an embodiment of the present invention, the initiator is selected from at least one of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), ammonium persulfate, benzoyl peroxide, and azobisisobutyronitrile.

[0028] According to an embodiment of the present invention, the interface stabilizer is selected from at least one of sodium dodecyl sulfate and hexadecyltrimethylammonium bromide.

[0029] According to an embodiment of the present invention, the cornflower-shaped polyaniline is prepared by the following method:

[0030] (1) dissolving aniline oligomers in an oil phase solvent to form an oil phase, dissolving a chiral doping acid and aniline in an aqueous phase solvent to form an aqueous phase, mixing the oil phase and the aqueous phase, adding an interfacial stabilizer, and performing ultrasonic emulsification at room temperature to obtain a water-oil two-phase system;

[0031] (2) adding an initiator to the water-oil two-phase system to carry out a polymerization reaction, and using an aqueous solvent to separate, wash, and dry the obtained reaction product to obtain the cornflower-like polyaniline.

[0032] The provided method first constructs a stable water-oil two-phase system, wherein aniline oligomers are dissolved in an oil phase solvent, and the acid solution formed by the chiral doping acid dissolved in the water phase solvent and aniline constitute the water phase, and then an interfacial stabilizer is added to stabilize the microcapsules. The amino groups in the aniline oligomers are stably distributed on the surface of the microcapsules due to the polarity difference, providing abundant active sites for the subsequent polymerization reaction of aniline. During the polymerization process, the chiral doping acid not only acts as a doping acid to promote the growth of polyaniline, but also acts as a chiral inducer to cause the polyaniline chain to form a chiral conformation. By controlling the reaction conditions, polyaniline with a unique cornflower-like structure is generated, and this cornflower-like structure presents a unique multilayer morphology with abundant interfaces between the layers.

[0033] According to an embodiment of the present invention, in step (1), the molar ratio of aniline to chiral doping acid is (1-1.5):1, and the mass ratio of the oil phase solvent to aniline oligomer is 3:1.

[0034] According to an embodiment of the present invention, the mass ratio of the water phase solvent to the oil phase solvent is (20-100):1.

[0035] According to an embodiment of the present invention, the ultrasonic emulsification conditions are a power of 600-800w and an emulsification time of 1-2h.

[0036] According to an embodiment of the present invention, the polymerization reaction is carried out at 0-5° C. with a constant stirring speed of 120-150 r / min and a reaction time of 4-6 hours.

[0037] According to an embodiment of the present invention, in step (2), the separation is carried out by filtering, and deionized water and ethanol are used in sequence for washing, and the washing is alternated. The drying temperature is 50-60° C. and the drying time is 1-2 h.

[0038] According to an embodiment of the present invention, the cornflower-shaped polyaniline modified carbon cloth substrate is prepared by the following method:

[0039] The cornflower-shaped polyaniline is mixed with a heat stabilizer and an antioxidant, and the mixed liquid obtained by impregnation treatment is attached to the carbon fiber cloth, and then the cornflower-shaped polyaniline-modified carbon cloth substrate is obtained by drying treatment.

[0040] According to an embodiment of the present invention, the immersion treatment temperature is 20-50° C., the immersion treatment time is 24-48 hours, and stirring treatment is performed at predetermined intervals during the immersion treatment.

[0041] The second aspect of the present invention provides an electromagnetic shielding polyurethane foam, which comprises, by weight:

[0042] 6-10 parts by weight of the cornflower-shaped polyaniline modified carbon cloth substrate described in the first aspect,

[0043] 20-70 parts by weight of polyether polyol,

[0044] 2-6 parts by weight of foam stabilizer,

[0045] 10-40 parts by weight of isocyanate,

[0046] and 0.5-5 weight parts of foaming agent.

[0047] The provided electromagnetic shielding polyurethane foam significantly improves the electromagnetic shielding performance of the polyurethane material itself by introducing a cornflower-shaped polyaniline-modified carbon cloth substrate.

[0048] According to an embodiment of the present invention, the polyether polyol is at least one of a difunctional polyether, a trifunctional polyether, or a multifunctional polyether.

[0049] According to an embodiment of the present invention, the foam stabilizer is at least one of a copolymer of polyethylene oxide methyl siloxane or silicone oil.

[0050] According to an embodiment of the present invention, the foaming agent is nitrogen.

[0051] The third aspect of the present invention provides a method for preparing the electromagnetic shielding polyurethane foam described in the second aspect, comprising the following steps:

[0052] (a) uniformly mixing a polyether polyol and a foam stabilizer to obtain a polyether component;

[0053] (b) uniformly mixing the polyether component, isocyanate and blowing agent in a predetermined ratio, and foaming the mixture under stirring to obtain a foamed material;

[0054] (c) coating the foaming material on the cornflower-shaped polyaniline-modified carbon cloth substrate and heating and curing the foaming material to obtain the electromagnetic shielding polyurethane foam.

[0055] According to an embodiment of the present invention, the mixing temperature in step (a) is 20-30° C., and the mixing time is 0.5-1 h.

[0056] According to an embodiment of the present invention, the foaming temperature in step (b) is 15-30° C., and the stirring speed is 300-800 rpm.

[0057] According to an embodiment of the present invention, the mass ratio of the polyether component to the isocyanate is (3.21-3.58):1.

[0058] The fourth aspect of the present invention provides the use of the cornflower-shaped polyaniline modified carbon cloth substrate described in the first aspect or the electromagnetic shielding polyurethane foam described in the third aspect in the fields of electromagnetic protection of electronic equipment, electromagnetic shielding space construction, and electromagnetic interference suppression.

[0059] The technical solution of the present invention has at least the following beneficial effects:

[0060] (1) The present invention provides a cornflower-shaped polyaniline modified carbon cloth substrate, comprising cornflower-shaped polyaniline, carbon fiber cloth, a thermal stabilizer and an antioxidant. Cornflower-shaped polyaniline can significantly enhance the interfacial polarization effect under the action of electromagnetic waves, generate a large number of electric dipoles, and its orientation and relaxation process effectively consumes electromagnetic energy and improves dielectric loss. At the same time, the multi-level nano-morphology of the cornflower-shaped structure increases the multiple reflection and scattering effects of electromagnetic waves, so that the material exhibits excellent electromagnetic shielding capabilities in a wide frequency range; and provides a large specific surface area, so that the interaction area between polyaniline and electromagnetic waves is increased, further enhancing the absorption and scattering capabilities of electromagnetic waves. Compared with polyaniline materials with traditional structures, cornflower-shaped polyaniline has better wave absorption capabilities. Cornflower-shaped polyaniline is composited with carbon fiber cloth. The high conductivity and flexibility of carbon fiber cloth are combined with the electromagnetic shielding properties of cornflower-shaped polyaniline, so that the composite material has excellent conductivity, mechanical stability and high-efficiency shielding performance. Under the action of electromagnetic waves, polyaniline absorbs and scatters electromagnetic waves, while carbon cloth provides a conductive path to promote rapid charge transmission, reduce interface resistance, and improve shielding effectiveness. The synergistic effect of the two makes the cornflower-shaped polyaniline modified carbon cloth substrate prepared by the present invention show excellent performance in high-frequency electromagnetic shielding applications.

[0061] (2) Through optimized water-oil two-phase interface polymerization, the cornflower-like polyaniline structure is precisely constructed. The present invention realizes the precise polymerization of aniline monomer by constructing a stable water-oil two-phase system, ensuring that the polymerization process is stable and controllable. By using a suitable interface stabilizer and ultrasonic emulsification technology, the oil phase droplets are evenly dispersed in the water phase to avoid phase separation problems, thereby obtaining a highly uniform reaction environment. By controlling the polymerization conditions, cornflower-like polyaniline with a large specific surface area and rich interface was successfully prepared.

[0062] (3) The interface bonding between polyaniline and carbon cloth is enhanced by impregnation treatment, and the conductivity and stability of the composite material are improved. Moreover, the cornflower-shaped polyaniline is evenly loaded onto the carbon fiber cloth substrate by the impregnation method, which solves the problem of poor interface bonding in the traditional polyaniline and carbon cloth composite process.

[0063] (4) The electromagnetic shielding polyurethane foam provided by the present invention can realize a lightweight, flexible and efficient shielding material. The present invention further coats a polyurethane foaming liquid on the basis of a cornflower-shaped polyaniline-modified carbon cloth substrate, and prepares an electromagnetic shielding polyurethane foam by reasonably controlling the foaming process. Polyurethane itself has the characteristics of light weight and high porosity, so that it can maintain mechanical flexibility while still ensuring the stability of the electromagnetic shielding function. Due to the high shielding effectiveness of cornflower-shaped polyaniline and the excellent conductivity of carbon cloth, the composite foam exhibits extremely high electromagnetic interference suppression capabilities, and can achieve a shielding effect of more than 70dB in the 8-18GHz frequency band. At the same time, the foam material has good processability and controllable properties, which can meet the needs of different industries for lightweight, high-performance electromagnetic shielding materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a SEM image of the cornflower-shaped polyaniline prepared according to Example 1 of the present invention. DETAILED DESCRIPTION

[0065] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0066] Cornflower-shaped polyaniline modified carbon cloth substrate

[0067] The present invention provides a cornflower-shaped polyaniline modified carbon cloth substrate, which comprises, by weight:

[0068] 20-40 parts by weight of cornflower-shaped polyaniline,

[0069] 30-50 parts by weight of carbon fiber cloth,

[0070] Heat stabilizer 0.3-1.6 parts by weight,

[0071] and 0.2-0.6 parts by weight of antioxidant.

[0072] The provided cornflower-like polyaniline modified carbon cloth substrate combines the excellent electromagnetic shielding properties of cornflower-like polyaniline, the high conductivity and mechanical stability of carbon cloth, and can be used as an electromagnetic shielding material to prepare high-performance electromagnetic shielding materials, thereby meeting the needs of modern electronic technology for lightweight and high-performance shielding materials. Among them, cornflower-like polyaniline is closely combined with carbon fiber cloth, and has high electromagnetic shielding effectiveness in the range of 8-12kHz, and the total shielding effectiveness (SET) is not less than 65dB.

[0073] According to a preferred embodiment, the cornflower-shaped polyaniline modified carbon cloth substrate is produced from the following raw materials in parts by weight:

[0074] 20 parts by weight of cornflower-shaped polyaniline, 30 parts by weight of carbon fiber cloth, 0.7 parts by weight of heat stabilizer and 0.2 parts by weight of antioxidant.

[0075] The mentioned heat stabilizer includes but is not limited to triphenyl phosphite, tris(2,6-dimethylphenyl) phosphite, trimethyl phosphate, etc. According to a preferred embodiment, the heat stabilizer is triphenyl phosphite.

[0076] The antioxidant mentioned includes but is not limited to tris(nonylphenyl)phosphite, distearylthiopropionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,5-di-tert-butyl-hydroxyphenyl propionate octadecyl alcohol ester or 2,2-methylenebis(4-methyl-6-tert-butylphenol) and the like. According to a preferred embodiment, the antioxidant is 3,5-di-tert-butyl-hydroxyphenyl propionate octadecyl alcohol ester. Preferably, the antioxidant is tris(nonylphenyl)phosphite.

[0077] The cornflower-shaped polyaniline mentioned is prepared by the following raw materials in parts by weight:

[0078] 6-10 parts by weight of aniline, 3-5 parts by weight of chiral doping acid, 0.1-0.5 parts by weight of oil phase solvent, 0.5-2 parts by weight of aniline oligomer, 20-50 parts by weight of water phase solvent, 1-5 parts by weight of initiator and 0.1-0.5 parts by weight of interface stabilizer.

[0079] According to a preferred embodiment, the cornflower-shaped polyaniline is produced by the following raw materials in parts by weight:

[0080] 6 parts by weight of aniline, 3.5 parts by weight of chiral doping acid, 0.2 parts by weight of oil phase solvent, 0.5 parts by weight of aniline oligomer, 20 parts by weight of water phase solvent, 1 part by weight of initiator and 0.1 parts by weight of interface stabilizer.

[0081] The chiral doping acid mentioned includes but is not limited to (R)-(+)-camphorsulfonic acid, (S)-(-)-camphorsulfonic acid, (R)-(-)-malic acid, (S)-(+)-tartaric acid, etc. According to a preferred embodiment, the chiral doping acid is (R)-(+)-camphorsulfonic acid.

[0082] The oil phase solvent mentioned includes but is not limited to chloroform, dichloromethane, carbon tetrachloride, toluene, xylene, n-hexane, etc. According to a preferred embodiment, the oil phase solvent mentioned is chloroform.

[0083] Herein, the "aniline oligomer" mentioned refers to a type of structural unit between monomer aniline and polymer polyaniline. Aniline oligomers can be a chain or ring-shaped molecular structure formed by a few aniline molecules connected by chemical reaction, and its degree of polymerization (i.e., the number of aniline units) is usually between 2 and 10, which is lower than the range of polymers. Common aniline oligomers are divided into dimers, trimers, and tetramers. According to a preferred embodiment, the aniline oligomers mentioned are aniline dimers. After aniline dimers are dissolved in the oil phase, a large amount of amino groups will be provided at the oil phase interface due to polarity, which serves as the active site for subsequent polyaniline polymerization. At the same time, moderate addition of aniline oligomers has the effect of assisting polyaniline crystallization and regulating reaction rate. According to a specific embodiment, the aniline oligomers mentioned include but are not limited to N-phenyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N-methyl-N-phenyl-p-phenylenediamine, etc. According to a preferred embodiment, the aniline oligomers mentioned are N-phenyl-p-phenylenediamine.

[0084] The aqueous phase solvent mentioned includes but is not limited to deionized water, ethanol, propanol, ethylene glycol, acetone, etc. According to a preferred embodiment, the aqueous phase solvent is deionized water.

[0085] The mentioned initiator includes but is not limited to 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), ammonium persulfate, benzoyl peroxide, azobisisobutyronitrile, etc. According to a preferred embodiment, the mentioned initiator is 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ).

[0086] The mentioned interface stabilizer includes but is not limited to sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, etc. According to a preferred embodiment, the mentioned interface stabilizer is sodium dodecyl sulfate.

[0087] According to a specific implementation, the cornflower-like polyaniline is prepared by the following method:

[0088] (1) dissolving aniline oligomers in an oil phase solvent to form an oil phase, dissolving a chiral doping acid and aniline in an aqueous phase solvent to form an aqueous phase, mixing the oil phase and the aqueous phase, adding an interfacial stabilizer, and performing ultrasonic emulsification at room temperature to obtain a water-oil two-phase system;

[0089] (2) adding an initiator to the water-oil two-phase system to carry out a polymerization reaction, and using an aqueous solvent to separate, wash, and dry the obtained reaction product to obtain the cornflower-like polyaniline.

[0090] The method provided first constructs a stable water-oil two-phase system, dissolves aniline oligomers in an oil phase solvent, dissolves chiral doping acid and aniline in an aqueous phase solvent, then adds an interfacial stabilizer, and mixes the two phases by ultrasonic emulsification, so that the oil phase is evenly dispersed in the aqueous phase in tiny droplets, ensuring the stability of the subsequent reaction environment and avoiding phase separation. Among them, the chiral doping acid plays a dual role, not only as a dopant to promote polymerization, but also as a chiral inducer to promote the formation of a chiral conformation of the polyaniline chain. By precisely controlling the interaction of each raw material and the reaction process, polyaniline forms a cornflower-like structure. This structure has a large specific surface area and rich internal interfaces. When electromagnetic waves are incident, a large number of electric dipoles will be formed at the interface due to differences in conductivity and dielectric constant. Their orientation and relaxation consume electromagnetic energy and increase dielectric loss; at the same time, the large specific surface area enhances the absorption and scattering ability of electromagnetic waves, significantly improving the electromagnetic shielding performance.

[0091] According to a specific implementation method, in step (1), the molar ratio of aniline to chiral doping acid is (1-1.5):1, the mass ratio of oil phase solvent to aniline oligomer is 3:1, and the ultrasonic emulsification conditions are power 800w and time 1.5h; the polymerization reaction is carried out in an ice-water bath at a constant stirring speed of 120r / min.

[0092] The mass ratio of the water phase solvent to the oil phase solvent is (20-100): 1. According to a preferred embodiment, the mass ratio of the water phase solvent to the oil phase solvent is 100:1.

[0093] In step (2), separation can be carried out by filtration, and deionized water and ethanol are used in sequence for washing, and the number of washing times with deionized water and ethanol are 5 and 3 respectively, and the washing is carried out alternately. The drying temperature is 50°C and the drying time is 1 hour.

[0094] The ultrasonic emulsification mentioned is 1-2 hours, for example, 1.5 hours. For example, the emulsification can be performed at a power of 600-800w for 1-2 hours. The polymerization reaction temperature mentioned is 0°C, and the reaction time is 4 hours.

[0095] According to a specific embodiment, the cornflower-shaped polyaniline used in the present invention has a structure as shown in formula (I):

[0096]

[0097] Then, the cornflower-like polyaniline is mixed with a heat stabilizer and an antioxidant, and the mixed liquid obtained by impregnation treatment is attached to the carbon fiber cloth, and then the cornflower-like polyaniline-modified carbon cloth substrate is obtained by drying treatment.

[0098] Cornflower-like polyaniline is compounded with carbon fiber cloth by an impregnation method to form a modified substrate, thereby improving its electrical conductivity and structural stability.

[0099] According to a specific implementation, the prepared cornflower-shaped polyaniline modified carbon cloth substrate has a thickness of 0.15 to 0.2 mm.

[0100] During the immersion process, the immersion temperature was 20° C., the immersion time was 24 h, and the mixture was stirred every 2 h for 15 min.

[0101] Electromagnetic shielding polyurethane foam

[0102] The present invention also provides an electromagnetic shielding polyurethane foam. According to a specific embodiment, the provided electromagnetic shielding polyurethane foam includes, by weight: 6-10 parts by weight of the above-mentioned cornflower-shaped polyaniline modified carbon cloth substrate, 20-70 parts by weight of polyether polyol, 2-6 parts by weight of foam stabilizer, 10-40 parts by weight of isocyanate, and 0.5-5 parts by weight of foaming agent. The provided electromagnetic shielding polyurethane foam combines the excellent electromagnetic shielding properties of cornflower-shaped polyaniline, the high conductivity and mechanical stability of carbon cloth, and the lightweight and porous properties of polyurethane foam, thereby improving the shielding effectiveness of polyurethane foam. In addition, the flexible properties of the foam make it suitable for the electromagnetic protection needs of electronic equipment with complex morphology, expand its application range, and meet the needs of modern electronic technology for lightweight and high-performance shielding materials.

[0103] According to a preferred embodiment, the electromagnetic shielding polyurethane foam is produced from the following raw materials in parts by weight:

[0104] 8 parts by weight of cornflower-shaped polyaniline modified carbon cloth substrate, 50 parts by weight of polyether polyol, 4 parts by weight of foam stabilizer, 30 parts by weight of isocyanate, and 2 parts by weight of foaming agent.

[0105] The provided polyether polyols include but are not limited to difunctional polyethers, trifunctional polyethers, or multifunctional polyethers, etc. According to a preferred embodiment, the polyether polyol is polyoxypropylene triol.

[0106] The foam stabilizer mentioned includes but is not limited to copolymers of polyethylene oxide methyl siloxane or silicone oil, etc. According to a preferred embodiment, the foam stabilizer mentioned is a copolymer of polyethylene oxide methyl siloxane.

[0107] The isocyanate mentioned is diphenylmethane diisocyanate. The blowing agent mentioned is nitrogen.

[0108] The electromagnetic shielding polyurethane foam mentioned above can be prepared by the following method:

[0109] (a) uniformly mixing a polyether polyol and a foam stabilizer to obtain a polyether component;

[0110] (b) uniformly mixing the polyether component, isocyanate and blowing agent in a predetermined ratio, and foaming the mixture under stirring to obtain a foamed material;

[0111] (c) coating the foaming material on the cornflower-shaped polyaniline-modified carbon cloth substrate and heating and curing the foaming material to obtain the electromagnetic shielding polyurethane foam.

[0112] Wherein, in step (a), the mixing temperature is 25°C and the mixing time is 1h; the temperature of the foaming machine is 24°C and the stirring speed is 600 rpm; the heating curing is carried out at 150°C and the curing time is 15min, and the mass ratio of the polyether component to the isocyanate is controlled at 3.42.

[0113] The cornflower-shaped polyaniline modified carbon cloth substrate and the electromagnetic shielding polyurethane foam provided by the present invention have broad application prospects in the field of materials, and are particularly suitable for electromagnetic interference protection of electronic equipment, 5G communication systems, smart wearable devices, and aerospace equipment.

[0114] If the specific conditions are not specified in the embodiments of the present invention, the conventional conditions or the conditions recommended by the manufacturer are used. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially. Only some of the reagents used in the embodiments of the present invention are provided below. Raw materials of different manufacturers and models do not affect the implementation of the technical solution of the present invention and the realization of the technical effects.

[0115] Table 1 Raw materials and manufacturers

[0116]

[0117]

[0118]

[0119] Example 1

[0120] Example 1 provides a cornflower-shaped polyaniline-modified carbon cloth substrate and electromagnetic shielding polyurethane foam.

[0121] The cornflower-shaped polyaniline is produced from the following raw materials in parts by weight:

[0122] 6 parts by weight of aniline, 3.5 parts by weight of chiral doping acid, 0.2 parts by weight of oil phase solvent, 0.5 parts by weight of aniline oligomer, 20 parts by weight of water phase solvent, 1 part by weight of initiator, and 0.1 parts by weight of interface stabilizer.

[0123] Among them, the chiral doping acid is (R)-(+)-camphorsulfonic acid; the oil phase solvent is chloroform; the aniline oligomer is N-phenyl-p-phenylenediamine; the water phase solvent is deionized water; the initiator is 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; and the interface stabilizer is sodium dodecyl sulfate.

[0124] The cornflower-shaped polyaniline modified carbon cloth substrate is produced from the following raw materials in parts by weight:

[0125] 30 parts by weight of carbon fiber cloth, 20 parts by weight of cornflower polyaniline, 0.7 parts by weight of heat stabilizer, and 0.2 parts by weight of antioxidant.

[0126] Wherein, the heat stabilizer is triphenyl phosphite; and the antioxidant is tris(nonylphenyl) phosphite.

[0127] The electromagnetic shielding polyurethane foam is produced from the following raw materials in parts by weight:

[0128] 8 parts by weight of cornflower-shaped polyaniline modified carbon cloth substrate, 50 parts by weight of polyether polyol, 4 parts by weight of foam stabilizer, 30 parts by weight of isocyanate, and 2 parts by weight of foaming agent.

[0129] Wherein, the polyether polyol is polyoxypropylene triol; the foam stabilizer is a copolymer of polyethylene oxide methyl siloxane; the isocyanate is diphenylmethane diisocyanate; and the foaming agent is nitrogen.

[0130] The cornflower-shaped polyaniline-modified carbon cloth substrate and the electromagnetic shielding polyurethane foam described in this embodiment are prepared by the following steps:

[0131] (1) Aniline oligomers are dissolved in an oil phase solvent to form an oil phase, and chiral doping acid and aniline are dissolved in an aqueous phase solvent to form an aqueous phase. After mixing, an interfacial stabilizer is added, and ultrasonic emulsification is performed at room temperature for 1.5 hours to obtain a stable water-oil two-phase system.

[0132] (2) Adding an initiator to the stable water-oil two-phase system obtained in step (1) to carry out polymerization reaction, the reaction temperature is 0°C, the reaction time is 4 hours, and after the reaction is completed, the cornflower-like polyaniline is separated, washed, and dried using an aqueous solvent. The SEM image of the prepared cornflower-like polyaniline is as follows: Figure 1 The method of the present invention can achieve accurate and controllable microscopic morphology of cornflower-shaped polyaniline.

[0133] (3) The cornflower-like polyaniline obtained in step (2) is mixed with a heat stabilizer and an antioxidant, and then attached to a carbon fiber cloth by an impregnation method, and then dried to obtain a cornflower-like polyaniline-modified carbon cloth substrate with high electromagnetic shielding performance.

[0134] (4) uniformly mixing the polyether polyol and the foam stabilizer to obtain a polyether component; then uniformly mixing the polyether component with the isocyanate and the foaming agent in a predetermined ratio, foaming under stirring conditions to obtain a foamed material; finally coating the obtained foamed material on the cornflower-shaped polyaniline modified carbon cloth substrate obtained in step (3), and heating and curing to obtain the electromagnetic shielding polyurethane foam.

[0135] Example 2

[0136] Example 2 provides a cornflower-shaped polyaniline-modified carbon cloth substrate and electromagnetic shielding polyurethane foam.

[0137] The cornflower-shaped polyaniline is produced from the following raw materials in parts by weight:

[0138] 6 parts by weight of aniline, 3 parts by weight of chiral doping acid, 0.2 parts by weight of oil phase solvent, 0.5 parts by weight of aniline oligomer, 20 parts by weight of water phase solvent, 1 part by weight of initiator, and 0.1 parts by weight of interface stabilizer.

[0139] Among them, the chiral doping acid is (R)-(+)-camphorsulfonic acid; the oil phase solvent is chloroform; the aniline oligomer is N-phenyl-p-phenylenediamine; the water phase solvent is deionized water; the initiator is 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; and the interface stabilizer is sodium dodecyl sulfate.

[0140] The cornflower-shaped polyaniline modified carbon cloth substrate is produced from the following raw materials in parts by weight:

[0141] 30 parts by weight of carbon fiber cloth, 20 parts by weight of cornflower polyaniline, 0.7 parts by weight of heat stabilizer, and 0.2 parts by weight of antioxidant.

[0142] The heat stabilizer is triphenyl phosphite; and the antioxidant is tris(nonylphenyl) phosphite.

[0143] The electromagnetic shielding polyurethane foam is produced from the following raw materials in parts by weight:

[0144] 8 parts by weight of cornflower-shaped polyaniline modified carbon cloth substrate, 50 parts by weight of polyether polyol, 4 parts by weight of foam stabilizer, 30 parts by weight of isocyanate, and 2 parts by weight of foaming agent.

[0145] Wherein, the polyether polyol is polyoxypropylene triol; the foam stabilizer is a copolymer of polyethylene oxide methyl siloxane; the isocyanate is diphenylmethane diisocyanate; and the foaming agent is nitrogen.

[0146] The preparation of the cornflower-shaped polyaniline modified carbon cloth substrate and the electromagnetic shielding polyurethane foam described in this embodiment includes the following steps:

[0147] (1) Aniline oligomers are dissolved in an oil phase solvent to form an oil phase, and chiral doping acid and aniline are dissolved in an aqueous phase solvent to form an aqueous phase. After mixing, an interfacial stabilizer is added, and ultrasonic emulsification is performed at room temperature for 1.5 hours to obtain a stable water-oil two-phase system.

[0148] (2) adding an initiator to the stable water-oil two-phase system obtained in step (1) to carry out a polymerization reaction at a reaction temperature of 0° C. for a reaction time of 4 hours. After the reaction is completed, an aqueous solvent is used for separation, washing, and drying to obtain cornflower-like polyaniline.

[0149] (3) The cornflower-like polyaniline obtained in step (2) is mixed with a heat stabilizer and an antioxidant, and then attached to a carbon fiber cloth by an impregnation method, and then dried to obtain a cornflower-like polyaniline-modified carbon cloth substrate with high electromagnetic shielding performance.

[0150] (4) uniformly mixing the polyether polyol and the foam stabilizer to obtain a polyether component; then uniformly mixing the polyether component with the isocyanate and the foaming agent in a predetermined ratio, foaming under stirring conditions to obtain a foamed material; finally coating the obtained foamed material on the cornflower-shaped polyaniline modified carbon cloth substrate obtained in step (3), and heating and curing to obtain the electromagnetic shielding polyurethane foam.

[0151] Example 3

[0152] Example 3 provides a cornflower-shaped polyaniline-modified carbon cloth substrate and electromagnetic shielding polyurethane foam.

[0153] The provided cornflower-shaped polyaniline is produced from the following raw materials in parts by weight:

[0154] 6 parts by weight of aniline, 4 parts by weight of chiral doping acid, 0.2 parts by weight of oil phase solvent, 0.5 parts by weight of aniline oligomer, 20 parts by weight of water phase solvent, 1 part by weight of initiator, and 0.1 parts by weight of interface stabilizer.

[0155] Among them, the chiral doping acid is (R)-(+)-camphorsulfonic acid; the oil phase solvent is chloroform; the aniline oligomer is N-phenyl-p-phenylenediamine; the water phase solvent is deionized water; the initiator is 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; and the interface stabilizer is sodium dodecyl sulfate.

[0156] The provided cornflower-shaped polyaniline modified carbon cloth substrate is produced from the following raw materials in parts by weight:

[0157] 30 parts by weight of carbon fiber cloth, 20 parts by weight of cornflower polyaniline, 0.7 parts by weight of heat stabilizer, and 0.2 parts by weight of antioxidant.

[0158] Wherein, the heat stabilizer is triphenyl phosphite; and the antioxidant is tris(nonylphenyl) phosphite.

[0159] The electromagnetic shielding polyurethane foam provided is produced from the following raw materials in parts by weight:

[0160] 8 parts by weight of cornflower-shaped polyaniline modified carbon cloth substrate, 50 parts by weight of polyether polyol, 4 parts by weight of foam stabilizer, 30 parts by weight of isocyanate, and 2 parts by weight of foaming agent.

[0161] Wherein, the polyether polyol is polyoxypropylene triol; the foam stabilizer is a copolymer of polyethylene oxide methyl siloxane; the isocyanate is diphenylmethane diisocyanate; and the foaming agent is nitrogen.

[0162] The provided cornflower-shaped polyaniline modified carbon cloth substrate and electromagnetic shielding polyurethane foam are prepared by the following steps:

[0163] (1) Aniline oligomers are dissolved in an oil phase solvent to form an oil phase, and chiral doping acid and aniline are dissolved in an aqueous phase solvent to form an aqueous phase. After mixing, an interfacial stabilizer is added, and ultrasonic emulsification is performed at room temperature for 1.5 hours to obtain a stable water-oil two-phase system.

[0164] (2) adding an initiator to the stable water-oil two-phase system obtained in step (1) to carry out a polymerization reaction at a reaction temperature of 0° C. for a reaction time of 4 hours. After the reaction is completed, an aqueous solvent is used for separation, washing, and drying to obtain cornflower-like polyaniline.

[0165] (3) The cornflower-like polyaniline obtained in step (2) is mixed with a heat stabilizer and an antioxidant, and then attached to a carbon fiber cloth by an impregnation method, and then dried to obtain a cornflower-like polyaniline-modified carbon cloth substrate with high electromagnetic shielding performance.

[0166] (4) uniformly mixing the polyether polyol and the foam stabilizer to obtain a polyether component; then uniformly mixing the polyether component with the isocyanate and the foaming agent in a predetermined ratio, foaming under stirring conditions to obtain a foamed material; finally coating the obtained foamed material on the cornflower-shaped polyaniline modified carbon cloth substrate obtained in step (3), and heating and curing to obtain the electromagnetic shielding polyurethane foam.

[0167] Example 4

[0168] Example 4 has the same raw materials and preparation method as Example 1, with the only difference being that the amount of the oil phase solvent used is replaced from 0.2 parts by weight to 0.1 parts by weight.

[0169] Example 5

[0170] Example 5 has the same raw materials and preparation method as Example 1, with the only difference being that the amount of the oil phase solvent used is replaced from 0.2 parts by weight to 0.3 parts by weight.

[0171] Comparative Example 1

[0172] Compared with Example 1, Comparative Example 1 removes the oil phase solvent and the interface stabilizer from the original formula. The only difference is that no oil phase solvent and the interface stabilizer are added, that is, no stable water-oil two-phase interface is constructed, and polyaniline is directly polymerized.

[0173] Comparative Example 2

[0174] Compared with Example 1, Comparative Example 2 removes the oil phase solvent, the interfacial stabilizer and the aniline oligomer from the original formula, that is, step (1) is not included. The only difference is that: a stable water-oil two-phase interface is not constructed, and aniline oligomers are not added during the polymerization process, that is, polyaniline is directly polymerized.

[0175] Effect comparison ratio

[0176] In order to verify the technical effects of the cornflower-shaped polyaniline-modified carbon cloth substrate and its electromagnetic shielding polyurethane foam prepared in each embodiment, the following experiments were conducted:

[0177] The electromagnetic shielding polyurethane foams prepared in Comparative Examples 1-2 and Examples 1-5 were taken as samples to be tested, and the electromagnetic shielding performance was tested respectively. The specific steps are as follows:

[0178] The electromagnetic shielding performance of the sample to be tested was tested using a vector network analyzer (Agilent N5227A) according to ASTM-D4935-18. The test frequency range was set to 1-18 GHz with a step length of 0.01 GHz on the vector network analyzer. The appropriate coaxial test fixture was selected to ensure that the sample was tightly connected to the test port. The full-band scanning test was then performed to record the shielding effectiveness (SE), reflection loss (SER) and absorption loss (SEA) at different frequencies. Each group was measured five times and the average value was taken to improve the data accuracy.

[0179] After the experiment, the results are shown in Table 2 below:

[0180] Table 2 Results of various embodiments and comparative examples

[0181] Serial number Shielding Effectiveness (SE) Reflection loss (SER) Absorption loss (SEA) Example 1 77.62 19.7 57.92 Example 2 65.53 16.65 48.88 Example 3 62.36 15.37 46.99 Example 4 67.98 18.33 49.65 Example 5 60.22 18.14 42.08 Comparative Example 1 25.22 14.56 10.66 Comparative Example 2 19.25 14.23 5.02

[0182] It can be seen from the experimental results of Examples 1, 2, and 3 that the electromagnetic shielding effectiveness of electromagnetic shielding polyurethane foam will be enhanced as the ratio of chiral doped acid to aniline increases. This is mainly because an appropriate amount of chiral doped acid can more effectively promote the formation of chiral conformation of polyaniline chains and optimize their microstructure. This structural change increases the interface polarization and multiple reflections inside the material, improves the absorption and scattering capabilities of electromagnetic waves, and thus improves the electromagnetic shielding effectiveness. However, when the ratio of chiral doped acid to aniline increases to a certain extent, the electromagnetic shielding effectiveness of the composite material gradually decreases. This is because too much chiral doped acid may destroy the orderly arrangement of polyaniline molecular chains, causing its structure to become chaotic, affecting the conduction of electrons between molecular chains, and weakening the material's loss capacity for electromagnetic waves. At the same time, excessive chiral doped acid may form agglomeration phenomena inside the material, reducing the uniformity of the material, making it impossible for electromagnetic waves to effectively interact with the material when propagating in the material, and ultimately leading to a decrease in electromagnetic shielding effectiveness.

[0183] It can be seen from the experimental results of Examples 1, 4, and 5 that the electromagnetic shielding effectiveness of the electromagnetic shielding polyurethane foam will show an increasing trend as the ratio of oily solvent to aqueous solvent increases. In the initial stage, the oily solvent and aqueous solvent in a suitable ratio can construct a stable water-oil two-phase system, providing a good environment for the polymerization reaction of aniline. This is conducive to the formation of a regular cornflower-like structure of polyaniline, increasing the specific surface area, increasing the internal interface, thereby improving the absorption and scattering ability of electromagnetic waves, and thus enhancing the electromagnetic shielding effectiveness. However, when the ratio of oily solvent to aqueous solvent increases to a certain extent, the electromagnetic shielding effectiveness decreases. This is because after the imbalance of the ratio, the stability of the water-oil two-phase system may be destroyed, resulting in the difficulty of the polymerization reaction to proceed smoothly, the structure of polyaniline cannot grow well, the regularity of its cornflower-like structure is affected, the specific surface area is reduced, and the internal interface is reduced. At the same time, the excessive change of the solvent ratio may affect the interaction between the components in the composite material, causing the overall performance of the composite material to decline, and ultimately leading to a weakening of the shielding ability of electromagnetic waves.

[0184] It can be seen from the experimental results of Comparative Examples 1, 2 and Example 1 that if a stable water-oil two-phase interface is not constructed, polyaniline with a special cornflower-like morphology cannot be synthesized. And without this special morphology, the electromagnetic shielding effectiveness of the material is also very low. This is because a stable water-oil two-phase interface can provide a uniform and suitable environment for the polymerization reaction of aniline. In this environment, the reactant molecules can fully contact and react, so that the growth process of polyaniline can proceed according to a specific mechanism, thereby forming a unique cornflower-like structure. This structure has good absorption and scattering capabilities for electromagnetic waves due to its large specific surface area and rich internal interfaces, thereby significantly improving the electromagnetic shielding effectiveness. If there is a lack of a stable water-oil two-phase interface, the reaction system will become chaotic, the reactants will be difficult to polymerize in an orderly manner, and a regular cornflower-like morphology cannot be formed. It is difficult to construct a microstructure inside the material that effectively acts on electromagnetic waves, resulting in low electromagnetic shielding effectiveness. Similarly, when the aniline oligomers in the original formula are removed, the crystallization rate of polyaniline will decrease, or even fail to crystallize, and naturally it will be impossible to synthesize polyaniline with a special cornflower-like morphology, and its electromagnetic shielding effectiveness will also be extremely low. Aniline oligomers play a key template and promotion role in the synthesis of polyaniline. It can serve as the starting point for the growth of polyaniline molecular chains, guide the gradual polymerization of aniline monomers, and accelerate the crystallization process. Without aniline oligomers, the growth of polyaniline molecular chains lacks effective guidance, the arrangement and aggregation between molecules become disordered, the crystallization process is hindered, and it is difficult to form polyaniline with a specific morphology and structure, and it is impossible to obtain a special cornflower-like morphology. Without the structural basis for enhanced electromagnetic shielding provided by this special morphology, the material's ability to shield electromagnetic waves is greatly reduced, showing extremely low electromagnetic shielding effectiveness.

[0185] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "specific implementation methods", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0186] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A cornflower-shaped polyaniline modified carbon cloth substrate, characterized in that: In parts by weight, it includes: 20-40 parts by weight of cornflower-shaped polyaniline, 30-50 parts by weight of carbon fiber cloth, Heat stabilizer 0.3-1.6 parts by weight, and 0.2-0.6 parts by weight of an antioxidant; Optionally, the thickness of the cornflower-shaped polyaniline-modified carbon cloth substrate is 0.1-0.2 mm.

2. The cornflower-shaped polyaniline modified carbon cloth substrate according to claim 1, characterized in that: The heat stabilizer is selected from at least one of triphenyl phosphite, tris(2,6-dimethylphenyl) phosphite, and trimethyl phosphate; Optionally, the antioxidant is selected from at least one of tris(nonylphenyl)phosphite, distearylthiopropionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,5-di-tert-butyl-hydroxyphenylpropionate octadecyl alcohol or 2,2-methylenebis(4-methyl-6-tert-butylphenol).

3. The cornflower-shaped polyaniline modified carbon cloth substrate according to claim 1, characterized in that: The cornflower-shaped polyaniline is prepared by using the following raw materials in parts by weight: 6-10 parts by weight of aniline, 3-5 parts by weight of chiral doping acid, 0.1-0.5 parts by weight of oil phase solvent, 0.5-2 parts by weight of aniline oligomer, 20-50 parts by weight of water phase solvent, 1-5 parts by weight of initiator, and 0.1-0.5 parts by weight of interface stabilizer.

4. The cornflower-shaped polyaniline modified carbon cloth substrate according to claim 3, characterized in that: The chiral doping acid is selected from at least one of (R)-(+)-camphorsulfonic acid, (S)-(-)-camphorsulfonic acid, (R)-(-)-malic acid, and (S)-(+)-tartaric acid; Optionally, the oil phase solvent is selected from at least one of chloroform, dichloromethane, carbon tetrachloride, toluene, xylene, and n-hexane; Optionally, the aniline oligomer is selected from at least one of N-phenyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, and N-methyl-N-phenyl-p-phenylenediamine; Optionally, the aqueous phase solvent is selected from at least one of deionized water, ethanol, propanol, ethylene glycol, and acetone; Optionally, the initiator is selected from at least one of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), ammonium persulfate, benzoyl peroxide, and azobisisobutyronitrile; Optionally, the interfacial stabilizer is selected from at least one of sodium dodecyl sulfate and hexadecyltrimethylammonium bromide.

5. The cornflower-shaped polyaniline modified carbon cloth substrate according to claim 3, characterized in that: The cornflower-shaped polyaniline is prepared by the following method: (1) Aniline oligomers are dissolved in an oil phase solvent to form an oil phase, a chiral doping acid and aniline are dissolved in an aqueous phase solvent to form an aqueous phase, the oil phase and the aqueous phase are mixed, an interfacial stabilizer is added, and ultrasonic emulsification is performed at room temperature to obtain a water-oil two-phase system; (2) adding an initiator to the water-oil two-phase system to carry out a polymerization reaction, and using an aqueous solvent to separate, wash, and dry the obtained reaction product to obtain the cornflower-like polyaniline; Optionally, in step (1), the molar ratio of the aniline to the chiral doping acid is (1-1.5):1, and the mass ratio of the oil phase solvent to the aniline oligomer is 3:1; Optionally, the mass ratio of the aqueous phase solvent to the oil phase solvent is (20-100):1; Optionally, the ultrasonic emulsification conditions are power 600-800w and emulsification time 1-2h; Optionally, the polymerization reaction is carried out at 0-5°C with a constant stirring speed of 120-150 r / min and a reaction time of 4-6 hours; Optionally, in step (2), the separation is carried out by filtering, and deionized water and ethanol are used in sequence for washing, and the washing is alternated. The drying temperature is 50-60° C. and the drying time is 1-2 h.

6. The cornflower-shaped polyaniline modified carbon cloth substrate according to claim 1, characterized in that: The cornflower-shaped polyaniline modified carbon cloth substrate is prepared by the following method: After mixing the cornflower-like polyaniline with a heat stabilizer and an antioxidant, the mixed liquid is attached to the carbon fiber cloth through an impregnation treatment, and then the cornflower-like polyaniline-modified carbon cloth substrate is obtained through a drying treatment; Optionally, the immersion treatment temperature is 20-50° C., the immersion treatment time is 24-48 hours, and stirring treatment is performed at predetermined intervals during the immersion treatment.

7. An electromagnetic shielding polyurethane foam, characterized in that: In parts by weight, it includes: 6-10 parts by weight of the cornflower-shaped polyaniline-modified carbon cloth substrate according to any one of claims 1 to 6, 20-70 parts by weight of polyether polyol, 2-6 parts by weight of foam stabilizer, 10-40 parts by weight of isocyanate, and 0.5-5 weight parts of foaming agent.

8. The electromagnetic shielding polyurethane foam according to claim 7, characterized in that: The polyether polyol is selected from at least one of a difunctional polyether, a trifunctional polyether, or a multifunctional polyether; Optionally, the foam stabilizer is selected from at least one of a copolymer of polyethylene oxide methyl siloxane or silicone oil; Optionally, the blowing agent is nitrogen.

9. The method for preparing the electromagnetic shielding polyurethane foam according to claim 7 or 8, characterized in that: include: (a) uniformly mixing a polyether polyol and a foam stabilizer to obtain a polyether component; (b) uniformly mixing the polyether component, isocyanate and blowing agent in a predetermined ratio, and foaming the mixture under stirring to obtain a foamed material; (c) coating the foaming material on the cornflower-shaped polyaniline-modified carbon cloth substrate and heating and curing the foaming material to obtain the electromagnetic shielding polyurethane foam; Optionally, the mixing temperature in step (a) is 20-30° C. and the mixing time is 0.5-1 h; Optionally, the foaming temperature in step (b) is 15-30° C., and the stirring speed is 300-800 rpm; Optionally, the mass ratio of the polyether component to the isocyanate is (3.21-3.58):

1.

10. Use of the cornflower-shaped polyaniline modified carbon cloth substrate according to any one of claims 1 to 6 or the electromagnetic shielding polyurethane foam according to any one of claims 7 to 8 in the fields of electromagnetic protection of electronic equipment, electromagnetic shielding space construction, and electromagnetic interference suppression.

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