283 results about "Polyimide membrane" patented technology

The invention discloses a process for synthesizing ammonia by coupling low-temperature plasma with electro-catalysis in the field of clean energy and green chemical industry, which comprises the following specific steps: mixing air and water vapor, feeding the mixture into a dielectric barrier discharge reactor, filling the reactor with a multi-stage heterojunction gradient doped carbon coated catalyst, generating active gas containing NOx under pulse high voltage, and condensing and then entering an electrocatalytic reduction unit. And an electro-catalysis product enters a photo-thermal separation module integrated with a Janus type photo-thermal electrode, the temperature of the electrode is locally increased under visible light irradiation, NH3 desorption is promoted, and finally high-purity ammonia is obtained through polyimide membrane separation. The multistage heterojunction gradient-doped carbon-coated catalyst adopted in the process is prepared through multiple steps and contains gradient-doped boron, sulfur and Au nanoparticles on the surface, NOx adsorption, electron transport and sintering resistance are synergistically improved, and efficient ammonia synthesis under mild conditions is achieved.

The invention discloses a high-temperature-resistant, bending-resistant and high-flexibility polyimide film for flexible display and a preparation method of the high-temperature-resistant, bending-resistant and high-flexibility polyimide film. According to the polyimide film, by introducing the nano silicon dioxide particles and constructing the porous structure design, the problems that a traditional polyimide film is insufficient in stability in a high-temperature environment, cracks are likely to be generated after bending, and the flexibility is poor are effectively solved. The polyimide film disclosed by the invention is prepared by adopting a diamine monomer and a dianhydride monomer as main raw materials, adding nano silicon dioxide particles, and carrying out solution polymerization, gelation, pore regulation and control and thermal imidization processes. The obtained polyimide film has a micron-sized porous structure, keeps stable at a high temperature of 400 DEG C, does not generate cracks after being bent for 100,000 times, has tensile strength of more than or equal to 150MPa, elongation at break of more than or equal to 25% and light transmittance of more than or equal to 85%, and is suitable for a substrate material of a flexible display device.

The invention discloses a preparation method of a proton exchange membrane water electrolysis hydrogen production membrane electrode, and belongs to the technical field of proton exchange membranes, a catalyst carrier is prepared, S101, a polyimide membrane is inversely fixed in a magnetron sputtering vacuum coating chamber, a cavity cover of the magnetron sputtering vacuum coating chamber is closed, vacuumizing is performed, and a substrate is heated; and S102, argon is introduced into a cavity of the magnetron sputtering vacuum coating chamber, coating is started, the power of the bismuth metal target is set to be 0.2-0.5 kW, and the deposition time is 60-1800 s. In the invention, the physical vapor deposition method is utilized to load the catalyst on the surface of the metal oxide carrier with high specific surface area and ordered nanostructure, so that the exposure of active sites of the catalyst is increased, the dosage of the noble metal catalyst is reduced, and the bonding strength between the catalyst and the carrier is enhanced; the catalyst is not easy to separate from the surface of the carrier, and large-scale slurry agglomeration is avoided.

The invention discloses a composite diaphragm, a preparation method thereof and a lithium ion battery. The composite diaphragm comprises a base membrane and a composite functional layer arranged on one side of the base membrane, and the composite functional layer is formed by compounding an independent high-temperature-resistant polymer porous membrane and a polytetrafluoroethylene porous membrane. Preferably, the high-temperature-resistant polymer porous membrane comprises one or more of an aramid fiber membrane and a polyimide membrane. By compounding the high-temperature-resistant polymer porous membrane and the polytetrafluoroethylene porous membrane, the overall thinning of the diaphragm is realized on the premise of ensuring excellent mechanical strength and thermal stability, and the ion migration impedance is effectively reduced, so that the rate capability, the cycle life and the safety performance of the lithium ion battery are remarkably improved.

The invention relates to the technical field of polyimide films, in particular to a PI film and a preparation method thereof. The PI film comprises the following raw materials in parts by mass: 100-150 parts of soluble polyimide resin, 5-15 parts of biphenyl epoxy resin, 5-10 parts of activated titanium dioxide, 1-5 parts of a curing agent and 1-3 parts of a curing accelerator, the soluble polyimide resin comprises the following raw materials in parts by mass: 5-10 parts of a first monomer, 25-30 parts of a second monomer, 50-60 parts of a third monomer, 20-30 parts of acetic anhydride and 5-15 parts of triethylamine. The size stability and heat resistance of the film can be remarkably improved, meanwhile, the outstanding transparency of the polyimide film can be guaranteed, and the application of the film in the field of flexible display is met.

The present invention relates to an intrinsically high thermal conductivity-low dielectric polyimide film, its preparation method, and applications. The polyimide is composed of polyimide A and polyimide B through blending or grafting. The polyimide film of the present invention has intrinsically high thermal conductivity, low dielectric constant and loss, and excellent heat resistance and mechanical properties. It has broad application prospects in integrated circuits, electronic packaging, and other fields.

A graphene neural electrode, a preparation method therefor, and use thereof. The preparation method comprises the following steps: (1) performing laser printing on a polyimide film according to a preset electrode pattern to obtain laser-induced graphene; (2) subjecting the laser-induced graphene to transfer printing to a water-soluble adhesive tape, then arranging a thermoplastic polymer thin film on one side of the laser-induced graphene away from the water-soluble adhesive tape, and then removing the water-soluble adhesive tape, so that the laser-induced graphene is subjected to transfer printing to the thermoplastic polymer thin film to obtain a first prefabricated product; (3) placing the first prefabricated product in a conductive polymer monomer solution for electrochemical polymerization, and forming a conductive polymer layer to obtain a second prefabricated product; and (4) arranging a thermoplastic polymer packaging layer on the conductive polymer layer of the second prefabricated product to obtain the graphene neural electrode. The graphene neural electrode prepared by using the method has excellent flexible characteristics and mechanical properties, high mechanical and electrochemical stability, and low electrochemical impedance, thereby achieving long-term stable signal monitoring in an organism.

The disclosure describes a device, method, and transfer apparatus for stamping thermoplastic composite blanks. The blanks may consist of laminated fibrous plies which may comprise continuous fibers in a thermoplastic polymer matrix. Supporting unidirectional fibers or holding tapes, pre-impregnated with polymer and extending beyond a shaping area's edges may be clamped in jaws, allowing the blank to be suspended and heated without sagging. The transfer system moves the blank between a heating station and a stamping station, where a punch and die may shape it while maintaining calibrated tension to reduce defects such as creasing or delamination. Advanced jaw mechanisms, including pivoting jaws with multiple clamping slots, enable differential tensioning of plies for precise forming of complex geometries. After stamping, excess fiber extensions may be trimmed and may be recycled. This approach eliminates the need for nonrecyclable polyimide films and improves process reliability for thick or heavy blanks.

A polyimide precursor for producing a flexible electronic device substrate that provides a polyimide with reduced charge-up, particularly a polyimide in the form of a film. When a polyimide film having a thickness of 10 μm is formed using the polyimide precursor, and a pair of electrodes is formed with a distance d on the polyimide film, and when the polyimide film is irradiated with a laser beam while applying a DC voltage with an electric field strength of 0.1 to 10 V / μm between the pair of electrodes; two SHG lights are observed between the pair of electrodes and satisfy a symmetry ratio of 0.5 or more. The symmetry ratio (LR ratio)=Ismall / Ilarge, wherein, Ilarge represents the peak intensity of the SHG light with the larger intensity, and Ismall represents the peak intensity of the SHG light with the smaller intensity.

A method for preparing a graphite film includes steps of preparing a carbonized frame carbonized at a temperature Ta, and an aromatic polyimide film or a carbonized film of the aromatic polyimide film carbonized at a temperature Tb, assembling the carbonized frame and the aromatic polyimide film or the carbonized film of the aromatic polyimide film into an intermediary body 1, carbonizing the intermediary body 1 at a temperature Td to produce a carbonized intermediary body, and graphitizing the carbonized intermediary body to produce the graphite film. The temperature Ta is larger than the temperature Tb and the temperature Tb is smaller than the temperature Td. The graphite film has a surface roughness expressed as an arithmetic mean height Sa of less than 18 nm, a thickness of 5 nm or more and less than 10 μm, and an area of 1.0 cm2 or more and less than 500 cm2.

The invention relates to the technical field of film covered wire production, in particular to a multi-splicing film covered wire production film covering machine which mainly comprises a machining table, a fixing frame, a pay-off assembly and a take-up assembly are fixedly installed on the top face of the machining table, the multi-splicing film covered wire production film covering machine further comprises an installation mechanism, the installation mechanism is arranged above the machining table, and the installation mechanism comprises a fixing frame located in the fixing frame and a compaction mechanism; and the compaction mechanism is arranged in the fixing frame. By means of the rotating shaft and the compaction wheels, a plurality of wires wound and wrapped with the polyimide film penetrate through the middles of the compaction wheels, the compaction wheels and the outer wall of the polyimide film are tightly extruded, and when the wires are pulled to be wound, due to the fact that the wires make close contact with the compaction wheels, the compaction wheels rotate and the two rows of compaction wheels are arranged in a staggered mode, the compaction wheels comprehensively compact the polyimide film; the polyimide film is tightly attached to the outer walls of the multiple wires, the polyimide film and the wires are connected more firmly, the polyimide film is not prone to loosening, and therefore the winding and wrapping quality of the whole wires is improved.

The application discloses a preparation method and application of fluorine-containing cross-linkable polyimide-based carbon molecular sieve membrane and belongs to the technical field of gas separation membranes. 4,4'-(hexafluoroisopropyl) diphthalic anhydride is used as a dianhydride monomer, 3,5'-diaminobenzoic acid and 4,4'-diamino diphenyl ether are used as common diamine monomers to copolymerize a polyamide acid solution; the polyamide acid solution is prepared into a casting solution, and after standing and defoaming, a polyamide acid membrane is prepared by using a coating method, and the polyamide acid membrane is imidized to prepare a polyimide membrane; the polyimide membrane is used as a polymer precursor membrane of the carbon molecular sieve membrane, is placed in a programmed temperature carbonization furnace with a protective atmosphere and is high-temperature baked to obtain the fluorine-containing cross-linkable polyimide-based carbon molecular sieve membrane. The carbon molecular sieve membrane is not only easy to prepare but also excellent in anti-aging capacity; the carbon molecular sieve membrane is used for CO2 / N2 and CO2 / CH4 separation, and has a high CO2 permeation coefficient and CO2 / N2 and CO2 / CH4 separation factors.

The invention discloses a three-layer co-extrusion multi-layer thermosetting and thermoplastic combined corona-resistant PI film and a preparation method thereof, and relates to the technical field of polyimide films. According to the invention, titanium dioxide and aluminum hydroxide are used as inorganic fillers, and layered shielding is formed by using the structural characteristics of aluminum hydroxide structure lamination and additional tight filling of spherical titanium dioxide, so that the movement of charges is hindered; meanwhile, a three-layer film layer structure is utilized, a high-performance thermosetting polyimide film is used as a supporting carrier, and thermoplastic polyimide resin containing aluminum hydroxide and titanium dioxide is used on the upper portion and the lower portion as functional layers to be attached to the surfaces of the thermosetting polyimide film layers, so that the tensile strength and the elongation at break are kept excellent; and the high-temperature resistance and high-voltage breakdown resistance of the film surface are further improved.

The disclosure provides a solvent resistant polyimide / polyethyleneimine@titanium dioxide nanohybrid ultrafiltration membrane with high solvent permeability and a preparation method thereof. The preparation method comprises the following steps: dissolving a titanium dioxide precursor Ti-BALDH and polyimide into N-methylpyrrolidone to prepare a casting solution, then coating on the non-woven fabric, and preparing the solvent resistant nanohybrid polyimide membrane in one step through a non-solvent induced phase separation-interface crosslinking-in-situ biomimetic mineralization coupling method. According to the disclosure, a solvent resistant polyimide / polyethyleneimine@TiO2 nanohybrid ultrafiltration membrane (PEIPI@TiO2) with high solvent permeability prepared through a simple non-solvent induced phase separation-interface chemical crosslinking-in-situ bionic mineralization coupling method.

The preparation method comprises the following steps: firstly, synthesizing polyamide acid by adopting a monomer polymerization strategy, pouring the polyamide acid onto a glass plate, casting to form a film, demolding with deionized water, washing and drying to successfully prepare the colorless transparent polyimide film. Secondly, colorless transparent polyimide films with different proportions are prepared by regulating and controlling the monomer proportion, and the physical and chemical properties are analyzed. A novel molecular main chain is constructed by utilizing different groups of different monomers, the colorless transparent polyimide film is prepared, and the colorless transparent polyimide film has excellent optical performance, thermal performance, mechanical performance and the like, can be used on a flexible organic light-emitting diode substrate, is crucial to the development of a flexible display technology, and has wide application prospects. And meanwhile, the method has far-reaching significance on development of portable electronic products such as wearable equipment and smart phones in the future.

The invention relates to the technical field of oil residue ammonia production tail gas treatment, in particular to an oil residue ammonia production tail gas treatment device and a tail gas treatment method.The oil residue ammonia production tail gas treatment device comprises a base, a large-particle filtering unit is fixedly installed on the upper side of the base, and a heat exchange assembly is fixedly installed on one side of the large-particle filtering unit; a spraying purification assembly is fixedly installed on one side of the heat exchange assembly, a purified gas conveying pipe is fixedly installed on the upper side of the spraying purification assembly, a gas conveying opening of the spraying purification assembly is fixedly connected with the heat exchange assembly, and a hydrogen extraction assembly is fixedly installed at an exhaust opening of the heat exchange assembly; the output end of the driving motor drives the lifting screw rod to rotate, the lifting screw rod drives the sleeve to move, inflated gas is compressed to reach set pressure, gas containing hydrogen is subjected to permeability extraction through the polyimide film, hydrogen in tail gas is extracted, and the purpose that the hydrogen in the tail gas is extracted is achieved. And the problem of resource waste caused by direct emission of hydrogen is avoided.

The invention belongs to the field of lithium ion batteries, and particularly relates to a semi-solid lithium battery diaphragm and a preparation method thereof.The semi-solid lithium battery diaphragm comprises a base membrane and gradient functional coatings coated on the two sides of the base membrane, the base membrane is a polyimide membrane, and each gradient functional coating comprises a bonding layer on the bottom layer, a regulating layer on the surface layer and a filling layer located between the bonding layer and the regulating layer; the bonding layer comprises a component A, and the component A comprises a polymer matrix, a disulfide bond-containing cross-linking agent, a coupling agent and a first solvent; the polymer matrix comprises polyimide and polyurethane; the filling layer comprises a component B and a component A, and the component B comprises core-shell particles and a dispersing agent, wherein the core-shell particles are formed by coating Li1. 3Al0. 3Ti1. 7 (PO4) 3 particles with ZrO2; the regulation and control layer comprises perfluorinated sulfonic acid resin, a plasticizer, an interface stabilizer, a second solvent and deionized water. Through the synergistic effect of all the layers in the gradient functional coating, the self-repairing performance of a damaged interface of the diaphragm can be achieved, and the strength of the diaphragm is improved.

The disclosure describes a device, method, and transfer apparatus for stamping thermoplastic composite blanks. The blanks may consist of laminated fibrous plies which may comprise continuous fibers in a thermoplastic polymer matrix. Supporting unidirectional fibers or holding tapes, pre-impregnated with polymer and extending beyond a shaping area's edges may be clamped in jaws, allowing the blank to be suspended and heated without sagging. The transfer system moves the blank between a heating station and a stamping station, where a punch and die may shape it while maintaining calibrated tension to reduce defects such as creasing or delamination. Advanced jaw mechanisms, including pivoting jaws with multiple clamping slots, enable differential tensioning of plies for precise forming of complex geometries. After stamping, excess fiber extensions may be trimmed and may be recycled. This approach eliminates the need for nonrecyclable polyimide films and improves process reliability for thick or heavy blanks.

The invention discloses preparation and application of thermoplastic polyimide acid resin and a polyimide film, the thermoplastic polyimide acid resin is formed by polymerizing one or more of diamine and dianhydride monomers in a polar solvent, and the thermoplastic polyimide film is formed by heating and curing the thermoplastic polyimide acid resin in a drying oven. The thermoplastic polyimide film has good thermodynamic properties and low water absorption and can meet the requirements for preparing a two-layer flexible copper-clad plate with high peel strength by using a lamination method, and the peel strength of the thermoplastic polyimide film reaches 0.70 kgf / cm or above and reaches 1.17 kgf / cm at most. In addition, the preparation method of the thermoplastic polyimide acid resin and the polyimide film provided by the invention is simple, green and environment-friendly, and the two-layer flexible copper-clad plate prepared from the thermoplastic polyimide acid resin and the polyimide film has excellent high moisture resistance and high heat resistance, can still keep excellent thermal stability and high peel strength in a high-moisture-heat environment, and has a wide industrial production prospect.

The invention discloses an amino-modified titanium-based MOF composite material and a preparation method thereof, and belongs to the technical field of sewage treatment.The preparation method comprises the steps that graphene aerogel powder serves as a carrier, titanium-based MOF containing a Ti-O-Mn heterostructure is loaded on the surface, then dopamine polymerization is conducted to obtain amino-modified titanium-based MOF powder, the amino-modified titanium-based MOF powder serves as a cross-linking site, and the amino-modified titanium-based MOF composite material is obtained. The surface of the amino-modified titanium-based MOF powder is coated with polyimide with a three-dimensional network structure, and the polyimide has a good removal rate on heavy metals in the aspect of sewage degradation and has excellent stability and recoverability; by constructing a three-dimensional network structure, the specific surface area of the polyimide film is increased, the synergistic effect of the polyimide film and titanium-based MOF is improved, polyimide is an organic high-molecular polymer and has high chemical inertness and a stable aromatic heterocyclic structure unit, amino is fixed through high crosslinking density, and the stability of the amino is improved.

The application discloses a super-thin polyimide film preparation process and a super-thin polyimide film current collector, relates to the field of polyimide film post-processing, and discloses the super-thin polyimide film preparation process, wherein a polyimide film with a thickness of 8-12 mu m is thinned to a polyimide film with a thickness of 3-6 mu m through alkali immersion; the polyimide film uniformly passes through an alkali tank; the moving speed of the polyimide film is 0.01-1 m / min; the alkali is NaOH solution and KOH solution; the mass concentration of the alkali is 3-10%; and the temperature of the alkali is 25-50 DEG C. The polyimide film with a thickness of 3-6 mu m is formed after acid pickling, water washing and drying; the acid pickling adopts hydrochloric acid with a concentration of 1-4%; and the alkali with a certain concentration can uniformly etch the surface of the polyimide film, so that the thickness of the polyimide film is thinned from 8-12 mu m to 3-6 mu m, the super-thin polyimide film is prepared, the super-thin polyimide film is used as a carrier of the super-thin current collector for preparing new energy batteries, and the super-thin current collector has high strength and stability.

The present invention provides a polyimide film and a manufacturing method therefor, wherein in the dimension change measurement by a thermomechanical analyzer (TMA) that performs a temperature rise procedure from 25° C. to 400° C. after storage for 48 hours at a humidity of 50% RH, the temperature-rise thermal expansion coefficient (50 to 200° C.) in the TD direction is −1.5 ppm / ° C. to 6 ppm / ° C., the temperature-rise thermal expansion coefficient (50 to 200° C.) being the slope of a straight line connecting a dimensional measurement value in the TD direction of the polyimide film as measured at 200° C. in the first run during the temperature rise procedure and a dimensional measurement value in the TD direction of the polyimide film as measured at 50° C. in the first run during the temperature rise procedure, and the dimensional measurement values in the TD direction correspond to dimensional change values calculated by converting, into 1 m, the length of a sample of the polyimide film used in the measurement by the thermomechanical analyzer.

The application relates to the technical field of gas filtering materials, in particular to a polyimide film composite material and a preparation method and application thereof, the composite material is mainly made of polyimide and Zn / g-C3N4, Zn / g-C3N4 accounts for 10-20 wt% of the mass of the polyimide; the preparation method is that the polyimide is stirred in a solvent to obtain a polyimide casting solution, then Zn / g-C3N4 is poured into the polyimide casting solution, stirring is carried out at 60-80 DEG C for 8-12 h, cooling is carried out to room temperature for 1-4 h, the defoaming casting solution is poured on a glass plate, a film with a thickness of 50-80 mu m is scraped out by using a coating machine, the scraped film is dried under vacuum at 100-120 DEG C for 8-12 h, peeling is carried out, annealing is carried out at 200-230 DEG C for 8-12 h, the obtained Zn / g-C3N4 composite polyimide film is placed in a plasma reactor for plasma treatment, and the polyimide film composite material is obtained. The polyimide film composite material can be used for efficient purification of helium, high selectivity is achieved while high flux is met, and high stability is also achieved.

The present application relates to the field of polyimide film, provide a kind of thermoplastic polyimide film steel plate preparation method and device, including the following steps;Provide steel foil, and prepare polyamide acid solution;Coated with a layer of polyamide acid solution on the rough surface of steel foil;The steel foil coated with polyamide acid solution obtained is placed on the rack in the furnace body and baked, and the steel foil covered with polyamide acid film is obtained;The steel foil covered with polyamide acid film obtained is subjected to thermal imidization, and the polyimide film steel plate is obtained.By being provided with the rack of metal material in the furnace body, the rack divides the furnace body into two heating cavities, and the two heating cavities are communicated through gap, and the heating pipe in lower chamber is heated towards the polyamide acid film on one side of copper foil, and the other side of polyamide acid film is not placed heating pipe, so that the heat in lower heating cavity is conducted to upper chamber through gap, and the other side of polyamide acid film is heated, and the heating efficiency is improved.

The present invention relates to the technical field of polyimide film surface modifiers, and more particularly to a polyimide film surface modifier and its preparation method and application. The polyimide film surface modifier is measured in concentration and includes: amines 9.0-10.0 g / L; quaternized polyvinyl imidazole 0.7-0.8 g / L; inorganic salt 0.2-0.4 g / L; alkylphenol polyoxyethylene ether 0.25-0.35 g / L; reducing agent 1.8-2.5 mL / L; inorganic base 0.8-1.0 g / L; alcohol amines 2.5-3.5 mL / L; the rest is deionized water. After the polyimide film surface modifier is metallized to the PI film surface, full coverage is obtained in a relatively short time, so that the PI film surface produces more chemical groups of phenolic groups and amines, plasma physical modification treatment can be exempted, and there is no need to use a PI adjuster, and the function of a pore-forming agent is combined, thereby reducing the cost of metallization treatment of the polyimide film surface.

The utility model discloses a flexible circuit board adopting aluminum as a conducting circuit, and relates to the technical field of flexible circuit boards. Comprising an aluminum foil layer which forms a conduction circuit through an etching process and plays a role in electrical conduction; the bottom polyimide film is located at the bottom layer of the flexible circuit board and plays a role in insulation and welding resistance; the bottom layer epoxy resin glue covers the bottom layer polyimide film and is used for bonding the bottom layer polyimide film and the aluminum foil layer; the top polyimide film is located on the top layer of the flexible circuit board and plays a role in insulation and welding resistance; and the top epoxy resin adhesive covers the lower surface of the top polyimide film and is used for bonding the top polyimide film and the aluminum foil layer. On the basis of a conventional flexible circuit board processing technology, aluminum is used for replacing copper to serve as a conducting circuit. According to the circuit board, the cost and the weight are remarkably reduced while the good conductive performance is guaranteed, and the circuit board has good corrosion resistance and is suitable for various severe environments.

The present application relates to a kind of preparation methods of peelable polyimide laminated film, which is made of multiple polyimide composite films by hot pressing forming, wherein the polyimide composite film is composed of polyimide film and adhesive, by controlling the thickness of adhesive layer, forming temperature, forming pressure and holding time, the peel strength of laminated film is controlled, and the peel strength controllable polyimide laminated film is obtained.Compared with the prior art, the present application effectively controls the peel strength of laminated film, and obtains a peelable polyimide laminated film with controllable peel strength.The method can control the peel strength of laminated film according to the use requirement, is easy to process and use, has low requirement for equipment, is easy to implement, and can be used for preparing peelable gasket.

The application provides a conical double-clad fiber probe integrated with photoacoustic excitation and detection, which integrates pump light excitation and detection light sensing through a conical double-clad fiber, integrates functions such as photoacoustic excitation, gas-light interaction and interference detection in a micro probe, effectively simplifies the device structure, reduces the volume, and significantly improves the integration and compactness. At the same time, the conical part of the conical double-clad fiber can realize lateral diffusion of pump light, so that it can fully act on the measured gas in the closed gas chamber without additional configuration of optical components such as mirrors, and the problem of weak photoacoustic signal in a small space is improved. In addition, the application uses a fiber Fabry-Perot interference structure to complete vibration detection with a polyimide diaphragm, replacing the traditional electronic detector, having excellent anti-electromagnetic interference capability, and can accurately identify weak vibration signals, effectively improving the sensitivity and operation stability of gas detection.

The invention relates to the technical field of composite films, and provides a high-strength and high-light-transmittance composite film and a preparation method thereof.The high-strength and high-light-transmittance composite film comprises a lower stacking structure including a base film layer, a reinforcing layer and a functional layer; the base film layer is a polyethylene glycol terephthalate (PET) film or a polyimide (PI) film, and the thickness of the base film layer is 50-100 microns; the strengthening layer is formed by curing a resin solution containing an imide ring and an acrylate monomer, and the thickness of the strengthening layer is 1-5 microns; the functional layer is an anti-reflection (AR) film layer and is composed of low refraction layers and high refraction layers in an alternating mode, and the total thickness of the functional layer is 50-500 nm. A mechanical basis is provided through the base film layer, the reinforcing layer forms a rigid network through curing of imide ring-containing resin and an acrylate monomer, the tensile strength and the pencil hardness are improved, the functional layer (AR film layer) reduces light reflection through a high-low refraction layer alternating structure, a complex application scene is adapted, a coating-curing process is adopted in the preparation process, and the preparation cost is reduced. The reinforced layer is cured through two steps of hot drying and ultraviolet light, the thickness of the AR film layer is accurately controlled through alternate coating, the process is efficient and controllable, and the method is suitable for industrial mass production.

Disclosed are: a polyimide film for producing a graphite sheet, the polyimide film containing a phosphorus compound having at least one alkyl group having 1-6 carbon atoms (inclusive); and a graphite sheet produced from the polyimide film.