321 results about "Aromatic diamine" patented technology

The invention discloses a toughened epoxy resin and a curing method thereof, and relates to the technical field of epoxy resins, the toughened epoxy resin comprises the following components: 100 parts of an epoxy resin matrix, specifically a mixture of bisphenol A epoxy resin and alicyclic epoxy resin, 5-35 parts of a composite amine curing agent, and 5-20 parts of a nano toughening agent, in particular to core-shell rubber particles grafted with epoxy groups on the surfaces, the core layer of each core-shell rubber particle is cross-linked polybutadiene, the shell layer of each core-shell rubber particle is polymethyl methacrylate, 0.5-3 parts of an accelerant comprising a bi-component synergistic accelerant, 1-5 parts of an interface enhancer, and a mixture of gamma-glycidyl ether oxypropyl trimethoxy silane and a titanate coupling agent, a bisphenol A type epoxy resin and a specific proportion of alicyclic epoxy resin are combined to construct an epoxy resin matrix according to a mass ratio of 2: 1, the epoxy resin matrix is matched with a composite amine curing agent prepared by carrying out a special three-step reaction on long-chain polyether diamine, aromatic diamine and anhydride, and key parameters such as molecular weight, functionality and molar ratio of the components are accurately regulated and controlled.

The invention provides a preparation method of an h-BN / PI high-temperature-resistant anticorrosive coating, and relates to the technical field of polymer composites.The preparation method of the h-BN / PI high-temperature-resistant anticorrosive coating comprises the steps that under the protection of inert atmosphere, aromatic diamine containing impurity element five-membered rings and aromatic dianhydride containing ether bonds are taken and subjected to a polymerization reaction in a polar aprotic solvent, and the h-BN / PI high-temperature-resistant anticorrosive coating is obtained. A polyamide acid solution is obtained; performing ultrasonic-assisted liquid phase stripping on the micron-sized hexagonal boron nitride to obtain single-layer hexagonal boron nitride; adding the single-layer hexagonal boron nitride into the polyamide acid solution for multiple times, and uniformly stirring to obtain a hexagonal boron nitride / polyimide composite solution; and coating the hexagonal boron nitride / polyimide composite liquid on a to-be-coated surface, and carrying out gradient heating curing to obtain the h-BN / PI high-temperature-resistant anticorrosive coating. The h-BN / PI high-temperature-resistant anticorrosive coating based on interaction of multiple hydrogen bonds has relatively good high temperature resistance, relatively good resistance mechanical property and excellent corrosion resistance.

The invention discloses supercritical fluid foaming polyimide wave-absorbing foam and a preparation method thereof.The thermoplastic polyimide is prepared by the steps that aromatic dianhydride, aromatic diamine and aliphatic diamine serve as comonomers, polyimide acid is generated through solution polymerization, and then high-temperature cyclization is conducted; wherein the mole number of the aliphatic diamine accounts for 10-50% of the total mole number of the diamine, and the free volume and glass transition temperature of a molecular chain are effectively regulated and controlled by introduction of the aliphatic diamine; the wave-absorbing foam is prepared by taking polyimide as a matrix, doping 1-20wt% of wave-absorbing filler, and foaming for 1-3 hours in a supercritical carbon dioxide or nitrogen environment at the temperature of 180-220 DEG C and the pressure of 9-25MPa, through molecular structure design, the adsorption capacity and impact resistance of polyimide to carbon dioxide are remarkably improved, and the prepared foam has the advantages of light weight, high porosity, uniform foam structure and excellent heat resistance, can realize effective electromagnetic wave absorption in an X wave band, and is suitable for the fields of aerospace stealth and electromagnetic compatibility protection.

The invention relates to the technical field of nylon materials, in particular to hydrophobic high-strength transparent nylon as well as a preparation method and application thereof. According to the preparation method, 3, 3 '-dimethyl-4, 4-diaminodicyclohexylmethane (MACM), aromatic diamine and fatty diacid are taken as reaction monomers, and the novel transparent nylon is obtained by adjusting the dosage ratio of the monomers and further adjusting the preparation process (regulating and controlling the reaction process). The transparent nylon provided by the invention has the advantages of hydrophobicity, high strength and high light transmittance. The technical problem that existing nylon is high in water absorption rate is solved. The hydrophobic transparent nylon provided by the invention can be used under the condition of high humidity, and has higher safety and longer service life; therefore, the application field of the transparent nylon is expanded.

Disclosed are compositions comprising: a first component comprising an isocyanate-functional prepolymer; a second component comprising a polyol having an Mn greater than 1,000 g / mol; an aromatic diamine; and a filler in an amount greater than 50 percent by weight to 93 percent by weight based on total weight of the composition. Also disclosed are methods for treating a substrate comprising contacting a substrate surface with one of the compositions disclosed. Also disclosed are substrates comprising a coating formed from one of the compositions disclosed herein on a surface thereof. Also disclosed are batteries comprising one of the substrates disclosed herein.

The invention discloses a process method for preparing a multi-component aramid copolymer through continuous polymerization, and relates to the technical field of high polymer material preparation, and the process method comprises the following steps: S1, preparing a premix: weighing one or more aromatic diamine monomers according to a certain mass ratio, dissolving the aromatic diamine monomers in an amide solvent or a solvent compounded by amides and hydrotropy salt, and stirring to obtain the premix; uniformly stirring and dissolving in a reaction kettle under the protection of a nitrogen environment to form a premix; s2, low-temperature pre-polycondensation reaction; s3, low-temperature polycondensation reaction; s4, post-treatment: neutralizing, washing and drying the multi-element aramid polymer powder obtained in S3, and removing the solvent and the hydrotropy salt to obtain pure and uniform-particle brown yellow powder; or the obtained polymerization stock solution is neutralized, defoamed and filtered to obtain a spinning stock solution, the intrinsic viscosity of the processed brown yellow powder or spinning stock solution is larger than 4.5 dL / g, the polymer powder / polymerization solution can be used for preparing the multi-element aramid fiber through spinning, and the method effectively reduces the industrial production cost of the multi-element cyclic aramid fiber and improves the production efficiency.

The invention discloses a polyimide composite material and a preparation method thereof, and relates to the technical field of functional composites.The polyimide composite material is composed of hollow quartz fibers and silicon-containing polyimide resin, the fiber volume content of the polyimide composite material is 45%-60%, and the density of the polyimide composite material is 1.25-1.55 g / cm < 2 >; wherein the silicon-containing polyimide resin is formed by polymerizing a mixture of aromatic dianhydride, aromatic diamine and diamine containing a siloxane structure, and an end-capping reagent. The preparation method comprises the following steps: synthesizing a polyamide acid solution, preparing a prepreg by preimpregnation, performing by a vacuum bag method, performing hot-pressing curing and performing high-temperature post-treatment. Through collaborative innovation of the components and the process, the preparation method is simple, and the composite material has ultralow density, ultrahigh heat resistance, low dielectric constant and high strength and is suitable for the fields of aerospace, 5G communication, semiconductors and the like.

The invention provides a preparation method of a polyimide film with high light transmittance and good mechanical properties and the polyimide film. The preparation method of the polyimide film comprises the steps that a first kind of diamine with the first molar mass and a first kind of binary anhydride with the second molar mass are added into a solvent to be dissolved and react to obtain a first mixture, the first kind of diamine is fluorine-containing aromatic diamine, and the first kind of binary anhydride is rigid straight type dianhydride with a rigid coplanar structure; a second kind of diamine with a third molar mass is added into the first mixture, after stirring and dissolving, a second kind of dianhydride with a fourth molar mass is added, a polyamide acid resin solution is obtained, the second kind of diamine is fluorine-containing aromatic diamine, and the second kind of dianhydride is distorted dianhydride with a non-planar structure; adjusting the viscosity of the polyamic acid resin solution by using a solution of a second type of dianhydride to obtain a polyamic acid solution with target viscosity; and mixing the polyamide acid solution with a chemical imidization reagent, and imidizing to obtain the polyimide film.

The invention provides a dye / ion separation membrane with pore diameter and charge coordinated regulation and control as well as a preparation method and application thereof, and belongs to the field of preparation of a double-layer ionic covalent organic framework (COFs) composite membrane. An aromatic polyamide ultrafiltration membrane is used as a base membrane, and a double-layer COFs membrane is constructed on the surface of the aromatic polyamide ultrafiltration membrane through a multi-time interfacial polymerization method. The first layer is a positive charge COFs layer formed by reacting a guanidyl monomer with 1, 3, 5-triformyl phloroglucinol (Tp); and the second layer is a negative charge COFs layer formed by reacting ionic aromatic diamine with Tp. By adjusting the type and concentration of the monomers, the pore diameter and charge distribution of the film layer can be synergistically regulated and controlled, and the double-layer composite film which is stable in structure and orderly stacked is constructed. The obtained membrane has molecular sieve separation and electrostatic regulation functions, can efficiently intercept organic dye molecules in high-salt printing and dyeing wastewater, and has high flux, high selectivity and good chemical stability.

The invention discloses a high-temperature-resistant benzimidazolone polyamide imide battery binder as well as a preparation method and application thereof, and belongs to the technical field of battery materials. The high-temperature-resistant benzimidazolone polyamideimide battery binder with uniformly distributed amide segments and imide segments is prepared through a method for activating aromatic diamine on one side of trimethylchlorosilane and changing the activity of amino groups on the two sides, the comprehensive performance of the high-temperature-resistant benzimidazolone polyamideimide battery binder is excellent, the defects that a traditional binder is poor in heat resistance and insufficient in chemical stability are overcome, and the service life of the high-temperature-resistant benzimidazolone polyamideimide battery binder is prolonged. The introduction of high-polarity groups can improve the wettability and ion transmission capability of the electrolyte, improve the solubility of the electrolyte so as to facilitate electrode forming, and can also form strong chemical bonds or physical adsorption with positive and negative inorganic active materials during application, thereby reducing the structural damage in the cycle process and improving the electrochemical performance of the battery. The lithium ion battery electrode can keep a stable structure in a high-temperature environment, the thermal runaway risk caused by high temperature is remarkably reduced, and the application requirements of the lithium ion battery in a fast charging or high-temperature energy storage scene are well met.

The invention discloses a halogen-free resin composition and a high-Tg low-loss copper-clad plate prepared from the halogen-free resin composition. The halogen-free resin composition comprises the following raw materials: a bismaleimide polymer, aromatic diamine, benzoxazine resin, a phosphorus flame retardant, an inorganic filler, an imidazole catalyst and a solvent. According to the invention, through prepolymerization of the bismaleimide polymer, especially the oligomer and the aromatic diamine, the brittleness problem of common bismaleimide is solved, the modified bismaleimide has excellent toughness, and the problems of bismaleimide precipitation and board resin agglomeration when a large amount of bismaleimide resin is used are solved.

The invention belongs to the technical field of synthetic high polymer materials, and relates to water-soluble polyamide acid salt as well as a water-phase one-pot preparation method and application thereof. The preparation method comprises the following steps: completely dissolving an aromatic dianhydride monomer in water to obtain a first solution, completely dissolving an aromatic diamine monomer and an organic alkali in water to obtain a second solution, mixing the first solution and the second solution, carrying out a polymerization reaction, after the polymerization reaction is finished, adding an end-capping reagent, continuously stirring until the end-capping reagent is completely dissolved, and removing water to obtain a finished product. The water-soluble polyamide acid salt is obtained. According to the preparation method, water is used as a solvent, a single-step polymerization reaction is adopted, any subsequent purification treatment step is not needed, the production process is green and environment-friendly, the process is simple and convenient, the cost is low, and the preparation method is not limited by the feeding amount of aromatic dianhydride monomers and the scale of a reaction system. The viscosity average molecular weight of the finally prepared water-soluble polyamide acid salt is 8.0 * 10 < 3 >-2.0 * 10 < 4 > g / mol, the film forming effect is excellent, and the water-soluble polyamide acid salt can be used as sizing liquid.

The invention provides a polyimide film for optical fibers and a preparation method of the polyimide film, preparation raw materials of polyamide acid slurry for optical fibers comprise aromatic diamine, aromatic dianhydride, ester functional monomers, an organic solvent and a coupling agent, and the ester functional monomers comprise diamino-containing ester and / or ester containing dianhydride groups; the specific ester functional monomer is added into the preparation raw materials, and the coupling agent is added in a matched manner, so that a polyimide coating formed by coating the polyamide acid slurry for the optical fiber outside a bare optical fiber has good adhesion, flexibility, heat resistance and tensile property, can effectively protect the optical fiber, also has excellent chemical peelability, and is suitable for popularization and application. The optical fiber can be quickly dissolved or fused after being infiltrated into a chemical reagent, so that the optical fiber can be thoroughly stripped from a base material without damaging the base material, and connection and use of the optical fiber are facilitated.

Disclosed are compositions including a first component and a second component. The first component includes an isocyanate-functional polyurethane prepolymer. The second component includes a first difunctional polyol and an aromatic diamine. The composition also may include an accelerator. Also disclosed are substrates comprising a coating formed from one of the compositions disclosed herein on a surface thereof. Also disclosed are armor assemblies comprising one of the substrates disclosed herein.

The invention discloses a diamine monomer based on lignin chemical modification, a polyimide material and a preparation method and application thereof. The invention provides a diamine monomer based on lignin chemical modification and a preparation method thereof. The diamine is used for synthesizing polyimide. And copolymerizing the diamine monomer with an aromatic diamine monomer and a dianhydride monomer to prepare the polyimide material. Due to the addition of diamine, the free volume between polyimide molecular chains can be increased, so that the obtained polyimide material shows considerable dielectric properties in high frequency under the condition that the polyimide material does not contain fluorine, and the polyimide material has good insulating properties, which provides possibility for application to the field of microelectronics.

The invention provides a low-water-absorptivity aramid fiber lithium battery diaphragm, a preparation method thereof and a lithium ion battery, and belongs to the technical field of battery diaphragms. Specific fluorinated side chain aromatic diamine with relatively high activity is adopted, a fluorinated side chain is introduced into the aramid diaphragm through condensation polymerization of aromatic dicarbonyl chloride and the fluorinated side chain aromatic diamine, and the fluorine content is increased by controlling the chain length of a perfluorinated chain, so that the water absorption rate and the water affinity of the aramid diaphragm are obviously reduced, and the performance of the aramid diaphragm is improved. The water content of the diaphragm can be controlled within the requirement of a commercial diaphragm in a vacuum baking mode. Meanwhile, the low-water-absorption aramid fiber lithium battery diaphragm provided by the invention has low swelling property and high heat resistance of the aramid fiber polymer, and the prepared lithium ion battery has excellent capacity, cycling stability and safety performance.

The invention provides a normal-pressure drying preparation method and application of polyimide aerogel powder, and the method comprises the following steps: taking aromatic diamine and aromatic dianhydride as monomers, dissolving the monomers in an organic solvent, and carrying out condensation polymerization to generate a polyamide acid solution; the preparation method comprises the following steps: introducing metal ions into a polyamide acid solution, constructing a cross-linked network among molecular chains by a cross-linking agent, and preparing a polyimide solution through chemical imidization reaction; a polyimide solution is directly injected into absolute ethyl alcohol to shorten the gel aging time, rapid solvent exchange is carried out, the production cycle of the polyimide aerogel is remarkably shortened, and the obtained suspension is filtered and dried at normal pressure to prepare polyimide aerogel powder. The polyimide aerogel powder can be used for preparing functional slurry, a high-performance battery diaphragm is processed through a coating process, and the battery performance is remarkably improved. According to the invention, the slurry and the industrial spraying production technology are combined, the batch preparation of the large-area composite battery diaphragm can be realized, and the method has a wide application prospect.

The invention discloses amino-terminated hyperbranched polyamide acid as well as a preparation method and application thereof. The amino-terminated hyperbranched polyamide acid is formed by polymerizing an aromatic anhydride monomer, an aromatic triamine monomer and an aromatic diamine monomer; the mole numbers of the aromatic anhydride monomer, the aromatic triamine monomer and the aromatic diamine monomer are a, b and c respectively, a: (b + c) = 1: 1-1: 1.5, and the proportion of b to c is any proportion. The amino-terminated hyperbranched polyamide acid disclosed by the invention not only has abundant terminal amino groups, but also contains a large number of polar groups such as ether bonds, imidazole rings, amide groups and carboxyl groups in molecular chains. Therefore, a stable water-based colloid emulsion can be formed in the presence of water and a small amount of organic solvent, other auxiliaries are not needed, and the interface performance and the mechanical performance of the composite material can be greatly improved.

The application discloses a kind of aromatic amine epoxy resin curing agent and its design method and insulating epoxy resin and its preparation method, belong to insulating technical field.At least two benzene ring structures are designed, and the benzene ring structures are connected by functional bridge bond;An amino functional group is respectively arranged at the two ends of the designed structure;High electron-withdrawing substituent group is not arranged at the ortho position of the designed amino functional group;Get aromatic amine epoxy resin curing agent;Functional bridge bond is arranged at the 1,4 or 1,3 substitution site of benzene ring structure.Multiple aromatic diamines are used as the curing agent component of epoxy resin, rigid aromatic structure is introduced into the epoxy main chain to enhance its thermal stability and improve the glass transition temperature;Functional bridge bond is introduced between benzene rings as breaking benzene ring conjugated structure, to improve electrical performance.Can prepare high-temperature stability and high-resistance high-voltage direct-current insulating epoxy resin.Help to solve the electrical performance of key insulating parts in DC GIS / GIL under the action of high temperature gradient and high electric field.

The present invention relates to the field of rubber material modification, and specifically to a functionalized rubber for an epoxy / amine curing system, which comprises component A and component B. The mass ratio of each raw material in component A is as follows: 100 parts of liquid unsaturated rubber, 50 parts of propylene glycol methyl ether, 1 - 5 parts of vinyl silane coupling agent, 1 - 10 parts of unsaturated epoxy diluent, 0.2 - 0.5 parts of initiator, 1 - 5 parts of laboratory grade three water, and 10 - 30 parts of 800 - mesh silica powder; the mass ratio of each raw material in component B is as follows: 100 parts of liquid unsaturated rubber, 40 parts of xylene, 10 parts of ethanol, 1 - 5 parts of laboratory grade three water, 0.1 - 0.5 parts of catalyst, 1 - 5 parts of oxidant, 1 - 3 parts of isocyanate, 1 - 3 parts of aromatic diamine, and 3 - 5 parts of blocking agent. The functionalized rubber of the present invention can improve the compatibility between the modified rubber material and the epoxy / amine system, reduce the influence of the modified rubber - like material on other properties of the system, and increase the flexibility of the system while ensuring the system strength.

The invention relates to the technical field of polyimide film preparation, in particular to a high-light-transmittance polyimide film and a preparation method thereof.The preparation method comprises the following steps that aromatic diamine monomers are subjected to vacuum drying and then dissolved in an organic solvent, dianhydride monomers are slowly and dropwise added after the temperature is increased, a polyamide acid solution is obtained through segmented temperature control curing, and a polyimide film is obtained; performing vacuum defoaming on the solution, coating a substrate with the solution, performing gradient heating imidization treatment to obtain a film crude product, and performing plasma surface treatment and inert atmosphere annealing to obtain the high-light-transmittance polyimide film. According to the preparation method, conventional monomers are adopted, through optimization of drying, polymerization, defoaming, film forming, imidization and post-treatment process parameters, introduction of special structural monomers or external filler adding is not needed, the process is simple, the cost is low, the preparation method is suitable for large-scale production, and the prepared polyimide film is high in light transmittance at the wavelength of 550 nm and high in transparency. The optical uniformity, the surface flatness, the thermal stability and the mechanical property are excellent.

The present application relates to a kind of based on Pickering emulsion method preparation heat-conducting filler-polyimide core-shell microspheres method, the method includes the following steps: aromatic diamine monomer is added with aromatic dianhydride monomer and organic polar solvent into reaction vessel and is reacted;Deposition in water, crush, wash and dry, to obtain polyamide acid salt precursor powder;Then with triethylamine and water stirring reaction, to obtain aqueous phase;Heat-conducting filler and hydrophobic polymer are dispersed in solvent to obtain oil phase;Oil phase and aqueous phase are mixed and emulsified, to obtain water-in-oil Pickering emulsion;Demulsification in precipitator, dry, to obtain heat-conducting filler-polyimide core-shell structure microspheres.The present application also provides the heat-conducting filler-polyimide core-shell microspheres prepared by the method, the method for preparing polyimide-based heat-conducting composite material using the core-shell microspheres and the composite material obtained therefrom.The present application method can efficiently prepare three-dimensional heat-conducting composite material with high thermal conductivity in horizontal and vertical directions.

[Problem] To provide a liquid-crystal polyester resin having excellent dimensional stability while having a low dielectric loss tangent. [Solution] A liquid-crystal polyester resin according to the present invention contains constituent units derived from an aromatic hydroxycarboxylic acid in an amount of 90 mol% or larger with respect to all the constituent units, and is characterized by: further containing a constituent unit derived from an aromatic diol and / or a constituent unit derived from an aromatic diamine and containing a constituent unit derived from an aromatic dicarboxylic acid; having a dielectric loss tangent at a measurement frequency of 10 GHz of 1.0×10-3 or less; giving an injection-molded piece which has a difference (anisotropy) in molding shrinkage between the flow direction (MD) and a direction (TD) perpendicular to the flow direction of 1.00 or less; having a melting point of 280°C or higher; and having a melt viscosity, as measured under the conditions of temperatures ranging from the melting point to [melting point + 20°C] and a shear rate of 1,000 / s, of 25 Pa·s or greater.

The invention discloses a tung oil-based non-isocyanate polyurethane photo-thermal anti-icing coating as well as a preparation method and application thereof, and belongs to the field of functional polymer materials. The method comprises the following steps: taking tung oil-based epoxy resin as a raw material, reacting with carbon dioxide to prepare tung oil-based cyclic carbonate, and reacting amino-terminated polydimethylsiloxane with terephthalaldehyde to obtain modified polydimethylsiloxane. And mixing tung oil-based cyclic carbonate, modified polydimethylsiloxane and a specific sulfur-containing aromatic diamine curing agent, spraying, and carrying out programmed heating curing to form the coating on the surface of the base material. A stable liquid-like layer can be formed on the surface of the coating, and the coating has extremely low surface energy and can obviously delay icing time. Meanwhile, the coating is endowed with efficient photo-thermal conversion capability through a D-pi-A molecular structure constructed by sulfur-containing diamine, and quick and active deicing can be realized under the irradiation of sunlight.

The present invention addresses the problem of providing a photosensitive resin composition which has excellent pattern processability, which makes a cured film that exhibits good elongation, and which exhibits good elongation even after having undergone a package reliability test. In order to solve the problem, the present invention proposes a photosensitive resin composition containing: at least one polymer compound selected from the group consisting of polyamide, polyimide, polyamideimide, and polybenzoxazole having, as a partial structure, a diamine residue derived from an aromatic diamine having no phenolic hydroxyl group with an ionization potential of 6.78 eV or more; a cationically polymerizable compound; and a photocationic polymerization initiator.

This polymer film 10 is characterized by comprising a first resin layer 11, a second resin layer 12, and a third resin layer, in that order. The polymer film is also characterized in that: the first resin film 11 forms one outermost layer of the polymer film 10; the first resin layer 11 includes a polyamide resin; the polyamide resin includes a copolymer polyamide that is a polycondensation product of diamine units and dicarboxylic acid units; the proportion of the number of aromatic diamine units to the total number of diamine units included in the polyamide resin that forms the first resin layer 11 is at least 75 mol%; the proportion of the number of isophthalic acid units to the total number of dicarboxylic acid units included in the polyamide resin that forms the first resin layer 11 is at least 22 mol%; the second resin layer 12 includes acid-denatured polypropylene; and the third resin layer 13 includes homopolypropylene.

The invention relates to a composite material, a solar cell and a preparation method and application of the solar cell. The composite material comprises a metal organic framework and polyimide in coordination connection with the metal organic framework, preparation raw materials of the polyimide comprise aromatic dianhydride and aromatic diamine, and at least one of the aromatic dianhydride and the aromatic diamine contains a fluorine group and carboxyl. The composite material is applied between a perovskite layer and an electron transport layer of a solar cell, the stability and the electron transport capacity are improved, interface defects are reduced, and therefore the photoelectric conversion efficiency and the carrier mobility of the solar cell are improved.

Provided are a polyimide compound including a repeating unit having an aromatic diamine component having a specific structure in which a side-chain benzylic position is regioselectively brominated, a gas separation membrane having a gas separation layer containing the polyimide compound, and a gas separation module and a gas separation apparatus each having the gas separation membrane.

This invention relates to an aqueous polyimide / SiO₂ nanocomposite coating and its preparation method. The preparation method of the aqueous polyimide / SiO₂ nanocomposite coating includes: dissolving an aromatic diamine monomer in a system composed of water and an organic base; adding an aromatic dianhydride monomer in batches to react and prepare an aqueous polyamic acid salt solution; adding a silane coupling agent to the aqueous polyamic acid salt solution to react and then adding an orthosilicate ester for in-situ hydrolysis and condensation to prepare an aqueous polyamic acid / SiO₂ nanocomposite coating; coating the aqueous polyamic acid / SiO₂ nanocomposite coating onto a substrate surface, followed by drying and imidization treatment to obtain the aqueous polyimide / SiO₂ nanocomposite coating. The aqueous polyimide / SiO₂ nanocomposite coating of this invention has excellent heat resistance and adhesion properties, and can be widely used in high-temperature protective coatings and electronic packaging fields.

The invention relates to an imidazolium functionalized polyimide anion exchange membrane for diffusion dialysis acid recovery and a preparation method of the imidazolium functionalized polyimide anion exchange membrane, and belongs to the technical field of polymer functional membrane materials. The method comprises the following steps: firstly, carrying out condensation polymerization on a dianhydride monomer BPA-2a and an aromatic diamine monomer to prepare intrinsic microporous polyimide PI-6B containing a hexabenzyl structural unit; performing bromomethylation modification on the polyimide PI-6B-Br by adopting liquid bromine to obtain brominated polyimide PI-6B-Br; and carrying out nucleophilic substitution reaction through an imidazole compound, and introducing an imidazolium cation functional group on a polymer main chain to obtain the imidazolium functionalized polyimide anion exchange membrane. The obtained anion exchange membrane has high ion exchange capacity, high acid dialysis coefficient and excellent acid / salt separation factors, and has good application prospects in the field of waste acid diffusion dialysis recovery.