128 results about "Nanofiber composites" patented technology

The invention discloses a preparation method of a cellulose acetate / thermoplastic polyurethane / polypyrrole composite conductive nanofiber aerogel composite pressure sensing material. The preparation method comprises the following steps: (1) preparing a cellulose acetate and thermoplastic polyurethane spinning solution; (2) preparing a cellulose acetate / thermoplastic polyurethane composite nanofiber membrane; (3) preparing cellulose acetate / thermoplastic polyurethane short nano dispersion liquid; (4) preparing a cellulose acetate / thermoplastic polyurethane / polypyrrole polymerization solution; and (5) preparing the cellulose acetate / thermoplastic polyurethane / polypyrrole composite conductive nanofiber aerogel. According to the preparation method, a high-temperature thermal annealing process is not needed, and the prepared nanofiber composite aerogel has high conductivity, ultralow volume density, high compression deformation performance and high pressure resistance sensing sensitivity.

The invention discloses a preparation method and application of three-dimensional intercalation multidirectional conductive MXene-based aerogel, and relates to the technical field of advanced electrochemical energy storage materials and devices. According to the MXene / conductive polymer and nanofiber composite aerogel developed by the invention, the two-dimensional conductive material, the pseudocapacitance polymer and the high-performance nanofiber are integrated in a three-in-one manner, so that collaborative optimization of conductivity, the number of active sites and structural stability is realized, and inherent defects of a single-component material are fundamentally avoided; and a universal solution is provided for solving the industrial problem of unbalanced performance of the electrode material.

The invention belongs to the related technical field of flexible electrodes, and discloses a preparation method, a product and application of a high-temperature-resistant flexible metallized ceramic nanofiber composite electrode. The method comprises the following steps: carrying out electrostatic spinning on electrostatic spinning sol doped with an organic polymer to obtain a precursor of a flexible ceramic nanofiber membrane; carrying out primary high-temperature calcination on the precursor to remove the doped organic polymer so as to obtain a flexible ceramic nanofiber membrane; growing and coating a metal conductive layer on the surface of the flexible ceramic nanofiber membrane to obtain an electrode precursor; and carrying out secondary high-temperature calcination on the electrode precursor to obtain the required composite electrode. The invention also discloses a product obtained by the preparation method and application. According to the invention, the problem that the flexible sensor is not resistant to high temperature is solved.

The invention relates to a covalent organic framework modified cellulose nanofiber composite diaphragm which is characterized in that cellulose nanofiber is used as a matrix, an amide type or amine type covalent organic framework layer is grown on the surface in situ, the loading capacity of a covalent organic framework is regulated and controlled, and a hierarchical pore structure with gradient pore diameter is constructed; the preparation method comprises the following steps: synthesizing a covalent organic framework precursor bonded with an imine bond on the surface of cellulose nanofiber in situ by a one-pot method under an acidic mixed solution and a heating condition, and regulating and synchronously reducing to convert into an amine type covalent organic framework; or after the imine bond bonded covalent organic framework is synthesized in two stages, the imine bond bonded covalent organic framework is selectively converted into an amide type covalent organic framework through oxidation modification; the obtained cellulose nanofiber compound coated with the covalent organic framework is subjected to the processes of film forming, solvent replacement, supercritical drying and the like, and the composite diaphragm is obtained; the diaphragm has excellent electrolyte wettability, high liquid absorption rate, good ionic conductivity and thermal stability, and can promote uniform transmission of lithium ions and inhibit growth of lithium dendrites.

The invention discloses a high polymer / nanofiber composite material with high mechanical property and high weather resistance as well as a preparation method and application thereof, and belongs to the technical field of polymer / nanofiber composite materials. According to the invention, polyether polyol participates in a prepolymerization reaction and is used for preparing a high-molecular polymer from modified nanofibers, and in the reaction process of a curing agent and isocyanate, the modified nanofibers and organic silicon are used as reinforcing phases to be added into the high-molecular polymer; the mechanical property, the weather resistance, the hydrophobic ice resistance, the chemical corrosion resistance and the wear resistance of the high-molecular polymer material are improved. The high polymer / nanofiber composite material with high mechanical property and high weather resistance provided by the invention is suitable for rain erosion protection of wind power blades. The preparation process is simple and efficient, the tensile strength, the elongation at break and the impact strength of the prepared high polymer / nanofiber composite material are remarkably enhanced, and the high polymer / nanofiber composite material is environment-friendly.

The invention discloses a rare-earth-based soil remediation catalyst as well as a preparation method and application thereof. The catalyst takes a composite oxide of micron-sized aluminum oxide and titanium dioxide as a carrier, a nano-fiber composite oxide of cerium oxide and copper oxide as an active component and a nano-particle composite oxide of iron oxide and manganese dioxide as a cocatalyst; on the basis of the mass of the carrier, the mass percentage of the active component is 5-10%, and the mass percentage of the cocatalyst is 3-6%. The catalyst synthesized through the method has the advantages of being good in soil compatibility, high in catalytic efficiency and the like, and the target of low-energy-consumption remediation of organic pollutant soil can be achieved.

The invention belongs to the technical field of flexible electronics, and relates to a flexible piezoresistive sensor based on an MXene multilevel heterostructure and a preparation method of the flexible piezoresistive sensor. The method comprises the steps that MXene nanosheets are attached to the surface of a thermoplastic polyurethane nanofiber substrate through electrostatic self-adsorption, a nanofiber composite layer is obtained, UIO-66-NH2 is dispersed in the thermoplastic polyurethane nanofiber substrate, and the surface of the thermoplastic polyurethane nanofiber substrate is modified with a first chitosan modification layer; the MXene nanosheets are embedded into the three-dimensional network of the polyurethane foam skeleton through dipping and extruding operation, a porous foam composite layer is obtained, and the surface of the polyurethane foam skeleton is modified with a second chitosan modification layer; and combining the nanofiber composite layer and the porous foam composite layer through a conductive adhesive containing silver paste, and carrying out packaging treatment to form the MXene multistage heterostructure with tightly combined interfaces. Based on the method, through the synergistic effect of the multistage heterostructures, high sensitivity, wide pressure detection range and high stability are realized at the same time.

The application belongs to the field of medical biological materials, and relates to a preparation method of a hierarchical nanofiber composite film for nerve repair and application thereof. The method comprises the following steps: preparing multilayer nanofibers with different internal stresses through continuous multiple electrostatic spinning units, stacking the multilayer nanofibers with different internal stresses to form a composite nanofiber film with an internal stress gradient; chemically crosslinking the composite nanofiber film; performing adhesion molecule adhesion treatment on the upper surface of the composite nanofiber film; and preparing the hierarchical nanofiber composite film with an internal stress gradient and capable of self-deforming under the action of liquid to wrap nerves. The film provided by the application has excellent flexibility, biocompatibility and degradation performance, can efficiently and quickly adhere to the surface of damaged nerves, provides a good support microenvironment for nerve cell growth, promotes nerve regeneration and repair, and has a wide application prospect in the field of peripheral nerve injury repair.

The invention discloses a stealth coating material for aviation aircrafts. According to the invention, a three-layer composite structure design is adopted; the intelligent sensing layer is composed of graphene quantum dots and a piezoelectric nanofiber composite network, so that real-time sensing of electromagnetic wave signals is realized; the tunable metamaterial layer comprises a liquid crystal elastomer matrix and nickel-titanium alloy nanowires dispersed in the liquid crystal elastomer matrix, and electromagnetic parameters of the material are dynamically adjusted by applying an electric field or a temperature field; vanadium dioxide nanoparticles, a photonic crystal structure and carbon nanotube aerogel are integrated in the multispectral stealth layer, and radar, infrared and visible light multispectral synergistic stealth is achieved. The coating is further integrated with a microencapsulation repairing agent and an intelligent control system, and has the self-repairing and self-adaptive adjusting functions. Compared with the prior art, 0.1-40 GHz ultra-wide frequency band radar wave absorption is achieved, the radar cross section is reduced by 25-30 dB, the infrared radiation characteristic is reduced by 80% or above, the surface density is only 1.2-1.5 kg / m, the weight is reduced by 65% compared with a traditional coating, and a key material technical support is provided for a new generation of stealth aircrafts.

The application discloses a kind of MXene modified polyimide nanofiber composite membranes and its preparation method and application, the method is prepared by acid etching method MXene nanosheet and polyamide acid molecular chain form strong hydrogen bond and coordination effect, significantly enhance interface binding force.MXene effectively transmits load, inhibits crack propagation, substantially improves the tensile strength and toughness of composite membrane, while extending the diffusion path of particulate matter, combined with the electrostatic adsorption effect produced by MXene itself conductivity, significantly improve the interception efficiency of PM0.3~PM2.5 fine particulate matter.The thermal imidization process ensures that PI matrix is completely converted into high-temperature-resistant structure, giving the material the ability to operate stably at high temperature for a long time.The composite membrane realizes four breakthroughs of high strength, high efficiency, low resistance and high dust capacity, providing a new solution for high-performance air filtration under harsh working conditions.

The application discloses a kind of superhigh temperature self-adaptive insulated cable of composite and preparation method thereof, which uses carbon nanotube fiber bundle as conductor, multiple layer aerogel-ceramic nanofiber composite felt as insulator, stress buffer layer formed by negative thermal expansion coefficient material is arranged between layers, and the outer sheath is chemical vapor infiltration SiC carbon fiber braided sleeve.The cable of the application has the advantages of ultra-light, high thermal stability, self-adaptive sealing and strong thermal shock resistance, and is suitable for extreme high temperature environment above 800 DEG C;The preparation method includes supercritical drying, pre-stretching winding and other key processes, to realize the high performance and reliability of the cable.

A composite nanofiber aerogel (CNA) is formed from aramid nanofibers (ANFs) combined with polyvinyl alcohol (PVA). These nanoscale constituents of the aerogel form 3D networks with high nodal connectivity and strongly welded connectivity joints between fibrils so that the structure has high stiffness and strength compared to other polymeric aerogels and successive breakage of crosslinks at the connectivity nodes affords energy dissipation while maintaining the overall structural integrity. A specific class of CNA with a specific solid content may be used to form a thin firm with a composite nanofiber framework (CNFF) that is useful in the manufacture of kirigami wearable electronics.

The invention provides a multi-modified high-nickel ternary positive electrode material, a preparation method thereof and a solid-state battery. The multi-modified high-nickel ternary positive electrode material comprises a high-nickel ternary core, a fast ion conductor coating layer and a polymer ceramic nanofiber composite coating layer, wherein the fast ion conductor coating layer and the polymer ceramic nanofiber composite coating layer are sequentially arranged on the surface of the high-nickel ternary core. According to the multi-modified high-nickel ternary positive electrode material disclosed by the invention, a dual cooperative defense system of the fast ion conductor layer and the polymer ceramic composite layer is constructed, so that the interface problems of surface side reaction, transition metal dissolution and the like are effectively solved, and a bulk phase structure is indirectly stabilized through external constraint and reduction of surface induction factors; therefore, the comprehensive improvement of the capacity, the rate capability and the cycle performance of the high-nickel material under the conditions of high voltage and long cycle is realized.

The application discloses a polymer-assisted exfoliated boron nitride nanosheet / aramid nanofiber composite heat-conducting film and a preparation method thereof. Hexagonal boron nitride is dispersed into sodium carboxymethyl cellulose aqueous solution and hydroxyethyl cellulose aqueous solution respectively to obtain first and second suspensions. Then, the polymers in the suspensions are homogenized and separated under a pressure of 75-90 MPa. The obtained dispersion liquid is mixed with aramid nanofiber dispersion liquid to form a film to obtain the boron nitride nanosheet / aramid nanofiber composite heat-conducting film. In the application, h-BN is introduced into CMC aqueous solution and HEC aqueous solution, and h-BN is exfoliated under a certain pressure. The coating degree of h-BN can be changed by changing the viscosity, and the collision force and shear force of h-BN on the homogenization channel in the homogenization process can be changed, so that BNNS with high aspect ratio and low defects is prepared, the intrinsic thermal conductivity of BNNS is improved, and the thermal conductivity of the boron nitride nanosheet / aramid nanofiber composite film is finally improved.

The invention discloses a preparation method of a BiOBr / LaNiO3 nanofiber composite photocatalyst, which is characterized in that a perovskite material LaNiO3 prepared by electrostatic spinning is used as a carrier, and BiOBr is loaded on the fiber surface by a solvothermal method to form a heterojunction structure. According to the composite material, separation of photon-generated carriers is promoted through heterojunction of BiOBr and LaNiO3 nanofibers, and the catalytic activity under visible light is remarkably improved. The invention further discloses application of the prepared BiOBr / LaNiO3 nanofiber composite photocatalyst in degradation of rhodamine B. The degradation efficiency of the BiOBr / LaNiO3 nanofiber composite photocatalyst on rhodamine B can reach 93% within 90 min, and after four times of circulation, the composite material shows good circulation stability. The method has the advantages of being low in cost, high in stability, environmentally friendly and the like, and a green solution is provided for organic dye pollution control.

The invention provides an ultra-light and ultra-thin nano-composite thermal fabric as well as preparation and application thereof, and belongs to the technical field of thermal insulation nano-materials. The preparation method comprises the following steps: mixing a polymer, aerogel and an organic solvent, and carrying out electrostatic spinning on an obtained spinning solution by using a sea-island electrospinning method to obtain a silicon-based aerogel and electrostatic spinning nanofiber composite membrane; the composite film and the lining cloth with the adhesive points are subjected to hot-pressing compounding, and the aerogel-compounded electric spinning nanofiber anti-dusting fabric is obtained. The heat conductivity coefficient of the aerogel compounded electro-spinning nanofiber anti-dusting fabric prepared by the preparation method disclosed by the invention is 0.06-0.07 W.m <-1 >. K <-1 >; at the same low temperature, the heat preservation duration is in positive correlation with the film thickness and / or gram weight, the fabric can be customized according to requirements so as to save the cost, and the temperature range of a heat preservation application environment is-20 DEG C to-80 DEG C; the preparation method has the advantages of powder falling prevention, simple process and high efficiency, and shows a good application prospect in the field of novel thermal insulation materials used in an extremely low-temperature environment.

The application provides a silk fibroin nanofiber composite film and a preparation method and application thereof. The preparation method comprises the following steps: preparing a self-supporting film with an ordered and continuous fiber network framework from a silk fibroin nanofiber dispersion liquid, wherein the fiber network framework serves as a reinforcing phase; contacting the self-supporting film with a solution containing a matrix phase and / or a functional phase, so that the matrix phase and / or the functional phase is filled into the fiber network framework of the self-supporting film to obtain a composite precursor film; and extruding the composite precursor film, or extruding and cross-linking the composite precursor film to obtain the silk fibroin nanofiber composite film. The method of the application adopts a time sequence separation strategy of 'first making a framework and then filling', and the self-assembly ordered structure of the silk fibroin nanofiber is completely reserved. The reinforcing phase, the matrix phase and the functional phase in the obtained composite film synergistically act, and the composite film has high mechanical strength, low swelling rate and functional integrability, and can be applied to the fields of implantable medical devices or biosensors.

The application discloses a kind of multistage filtration systems for ultrapure water production process, multistage filtration system includes primary filter device and secondary filter device, RO concentrated water stock solution is sequentially transported to primary filter device, secondary filter device;The inside of primary filter device is equipped with colloidal silica filter material, the inside of secondary filter device is equipped with colloidal iron filter material;Colloidal silica filter material is amino functionalized MOFs nanofiber composite membrane, colloidal iron filter material is nanofiber membrane with surface grafted hydroxamic acid group.The multistage filtration system for ultrapure water production process provided by the application has excellent colloidal silica removal effect and excellent colloidal iron removal effect.

The invention discloses a protein nanoparticle-nanofiber composite material and a preparation method thereof, and belongs to the technical field of food processing and functional protein materials. The method comprises the following steps: (1) taking fresh egg white, diluting and stirring to obtain uniform egg white protein dispersion liquid; (2) performing acylation modification on the egg white protein dispersion liquid to increase surface negative charges and improve conformation flexibility; (3) performing controllable enzymolysis on the acylated egg white protein, so that part of peptide chains of the acylated egg white protein are broken and oligopeptide with self-assembly capability is formed; and (4) carrying out heat treatment on the enzymolysis product, inducing the peptide fragment to be self-assembled to form nano-particles while inactivating the protease through heat treatment, further forming a nano-fiber network dominated by a beta-folding structure, and finally obtaining the protein nano-particle-nano-fiber composite system. Through the synergistic effect of acylation, enzymolysis and heat treatment, accurate conversion of protein from a natural spherical conformation to a functional nanostructure is achieved, and the obtained composite material has the dispersion stability of particles and the network enhancement effect of fibers and has excellent foamability, emulsibility and gelling property.

The application discloses a kind of β-CD / waste polyester electrostatic spinning composite nanofiber membrane and its preparation method and application, CWP spinning solution and β-CD solution are respectively placed in electrostatic spinning machine receiving drum two ends and are prepared with the " honeycomb structure " β-CD / CWP nanofiber composite membrane, its porosity is high, and β-CD is " bowl shape " structure, these special structures are conducive to reduce filtration resistance, improve the removal of particulate matter PM in oil smoke and volatile organic gas COFs, so as to obtain excellent comprehensive filtration performance.Oil smoke detection system is used to test the real oil smoke purification performance of composite membrane (>90%), which is much higher than that of commercially available oil smoke purification materials;After 120 min cycle purification, the purification efficiency is flat with the initial efficiency (>90%), and can be widely used in high-end air filtration, oil-gas separation and other fields.

The invention relates to the technical field of adsorption type air water extraction, in particular to all-weather air water production equipment based on a nanofiber composite material. The device can be used for continuously producing water from air in a wide range, namely in a relative humidity range of 5-100%. The compact structure facilitates implementation of environment miniaturization according to design; and the method can also be applied to dehumidification scenes such as factories. The device is simple in structure, and after the range is expanded, the requirement for air water production with large demand can be met.

The invention belongs to the field of composite membranes, and particularly relates to a waterproof breathable membrane based on a micropore-nanofiber composite structure and a preparation method of the waterproof breathable membrane. Comprising the following steps: preparing an ePTFE microporous membrane by adopting a thermally induced phase separation method or a two-way stretching method, and carrying out corona treatment on the ePTFE microporous membrane; dissolving a fiber-forming polymer in an organic solvent to form a uniform spinning solution; the ePTFE microporous membrane obtained after corona treatment is fixed to a receiving roller; carrying out electrostatic spinning by adopting a multi-jet nozzle to obtain a nanofiber / base membrane composite blank; meanwhile, an N, N-dimethylformamide steam treatment cabin is arranged behind the receiving roller, then continuous interface fusion and reinforcement treatment is immediately carried out on the just deposited nanofiber / base membrane composite blank through a hot pressing roller, and the composite membrane is obtained; and drying and rolling the composite film to obtain the waterproof breathable film with the micropore-nanofiber composite structure. The breathable film provided by the invention realizes extremely high hydrostatic pressure and excellent water vapor permeability, and also has good mechanical strength and durability.

The present application relates to a kind of biomimetic reticular nanofiber composite coating and its preparation method and infectious bone defect repair application, belong to biomedical material field.The present application is aimed at solving the technical problem of the poor bone integration of implant in infectious bone defect.The present application provides a kind of biomimetic reticular nanofiber composite coating, which is formed by layer-by-layer self-assembly on the surface of implant by lysozyme amyloid fiber and polyphenols (such as tannin etc.) Form reticular structure, then prepared with bioactive metal ions coordination;The number of coating layers is 4-8 layers.Preparation method includes lysozyme fiberization, alternate deposition and ion loading steps.The composite coating of the present application has broad-spectrum antibacterial, antioxidant stress and promotes osteogenesis function;In animal model, bacterial load is reduced by 80%, bone volume fraction and trabecular bone parameters are significantly improved, and can realize anti-bacterial biofilm infection-antioxidant stress-angiogenesis-promote bone regeneration synergy.

This invention discloses a high-efficiency disinfection air filter paper and its preparation method, relating to the field of filter material technology. The invention first utilizes ethylene (chloromethyl)dimethoxysilane to modify nano-titanium dioxide, N-(2,3-epoxypropyl)phthalamide, and chitosan to generate an antibacterial agent. This agent is then copolymerized with N-hydroxymethylacrylamide and acrylamide to form an antibacterial emulsion. A multi-layer polyvinylidene fluoride nanofiber composite membrane is then prepared by combining a scaffolded polyvinylidene fluoride fiber membrane with an ultra-fine polyvinylidene fluoride fiber membrane, achieving a low-resistivity filter paper. Finally, the antibacterial emulsion is sprayed onto the surface, promoting the fixation of the modified titanium dioxide onto the substrate surface and improving the filter paper's burst resistance. The filter paper prepared by this invention exhibits antibacterial, burst-resistant, and low-resistivity properties.

The invention discloses a preparation method of a SnO2 / ZnO nanofiber composite material. The preparation method comprises the following steps: S1, preparing nanofiber-shaped SnO2 by an electrostatic spinning method; s2, the nanofiber-shaped SnO2 and the nanofiber-shaped ZnO are compounded through an electrostatic spinning method, and the SnO2 / ZnO nanofiber composite material is obtained. The gas sensitive sensor prepared from the SnO2 / ZnO nanofiber composite material can realize specific detection of H2 at room temperature, the highest responsivity to 100 ppm H2 at room temperature can reach 237.5, which is 20 times of the responsivity of a pure SnO2 material, the detection limit of the sensor is as low as 100 ppb, and high response and high stability can still be maintained after continuous testing for 30 days.

The application discloses an electric response nanofiber composite film and a preparation method and application thereof, and the preparation method comprises the following steps: vacuum drying and grinding a metal organic framework material UiO-66, dissolving the obtained UiO-66 powder in N,N-dimethylformamide, and ultrasonic treatment to make the UiO-66 powder uniformly dispersed; dissolving PVDF powder in the solution, stirring until the PVDF powder is completely dissolved, adding acetone to obtain an electrospinning precursor solution; electrospinning the electrospinning precursor to obtain a PVDF / metal organic framework composite nanofiber film; and then performing drying and annealing treatment to obtain the electric response nanofiber composite film. The composite film has high flexibility, a high specific surface area, excellent piezoelectric response and sound-electric conversion efficiency, and solves the problems of low beta phase content and poor force-electric coupling efficiency of traditional organic piezoelectric materials; the composite film has a wide application prospect in the fields of flexible piezoelectric sensors, sound wave detectors, hydrophones and wearable sound-electric devices.

The invention belongs to the field of hydrogel, and particularly relates to high-toughness antifouling antibacterial hydrogel and a preparation method thereof. The high-toughness antifouling antibacterial hydrogel provided by the invention is prepared by mixing polyvinyl alcohol, betaine methacrylate sulfonate, a MoS2 loaded cellulose nanofiber composite material, a mesoporous material loaded with a bactericide, sulfuric acid, an initiator and water and then performing freeze thawing treatment. According to the preparation method, the mesoporous material loaded with the bactericide and the MoS2 loaded cellulose nanofiber composite material are introduced into the hydrogel, so that the anti-adhesion performance, the bactericidal performance and the mechanical performance of the hydrogel are greatly improved. According to the invention, the problems of single antifouling mechanism and poor mechanical property of the traditional hydrogel are solved by constructing a hydrogel system of anti-adhesion, sterilization and mechanical property enhancement, and a good solution is provided for long-acting antifouling of marine equipment.

This invention discloses an aminated graphene oxide / carboxylated cellulose nanofiber composite ultrafiltration membrane based on phase inversion and its preparation method, belonging to the field of membrane separation. The casting solution of the ultrafiltration membrane has the following mass fractions: polyvinylpyrrolidone: 1 wt.%, polyethersulfone: 20 wt.%, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide: 0.05 wt.%, N-methylpyrrolidone: 78.7 wt.%, and the total mass fraction of aminated graphene oxide and carboxylated cellulose nanofibers is 0.25 wt.%; the mass ratio of aminated graphene oxide to carboxylated cellulose nanofibers is (0.5-1.5):1. This invention solves the problems of low rejection rate and severe membrane fouling caused by the mismatch between the molecular weight cutoff range and low molecular weight dyes in the prior art, and has the potential for application in wastewater treatment device preparation.

This invention discloses a method for preparing a polyphenylene sulfide (PPS) / aramid nanofiber composite film, belonging to the field of high-temperature resistant, high-strength, and high-toughness composite film preparation. The preparation method includes the following steps: 1) preparing PPS fiber paper using a wet-process papermaking method, and then coating the surface with aramid nanofibers using a coating process; 2) attaching an adhesive to the surface of the composite film using a spreading process, and obtaining the composite film through a series of hot-pressing processes and oxidation treatment. The composite film prepared by this invention exhibits strong high-temperature dimensional stability, high insulation, and strong mechanical properties.

The application discloses a composite film with insulation, heat conduction and electromagnetic shielding functions, a preparation method and application, and the composite film is composed of an upper layer, a middle layer and a lower layer; the middle layer is a graphene / aramid nanofiber composite material with a content of 50-80 wt%; and the upper layer and the lower layer are both boron nitride nanosheet / aramid nanofiber composite materials with a content of 70 wt%. Through the above scheme, the boron nitride and the graphene play their respective roles and complement each other, and the composite film has the advantages of simple structure, simple preparation process, excellent performance and the like, and has high practical value and popularization value in the technical field of new material technology.