102 results about "Diaminodiphenyl ether" patented technology

The invention discloses a preparation method of a polyimide-boron nitride nanosheet heat-conducting composite film. The preparation method comprises the following steps: firstly, dispersing boron nitride nanosheets into N, N-dimethylacetamide containing poly (diallyldimethylammonium chloride) to prepare slurry; meanwhile, 4, 4 '-diaminodiphenyl ether reacts with pyromellitic dianhydride to prepare a polyamide acid solution. And mixing the two materials, forming a layered structure through vertical and horizontal temperature gradients by adopting a bidirectional freezing casting technology, and freezing by liquid nitrogen to obtain the aerogel in oriented arrangement. And performing hot pressing and step-by-step thermal imidization treatment to obtain the heat-conducting composite film. According to the method, the highly-oriented arrangement of boron nitride nanosheets is constructed through bidirectional freezing casting, and the composite film has excellent heat-conducting property and keeps good mechanical strength and flexibility in combination with the surface modification effect. The process is simple and controllable, and is suitable for the fields of flexible electronics, 5G heat dissipation, battery thermal management and the like.

The invention discloses a fireproof flame-retardant battery diaphragm, a preparation method thereof and a fireproof flame-retardant battery, and relates to the technical field of battery diaphragms. When the fireproof flame-retardant battery diaphragm is prepared, boric acid diglyceride and chlorinated trimellitic anhydride mixed liquor react to prepare a flame-retardant monomer; the preparation method comprises the following steps: polymerizing 4, 4 '-diaminodiphenyl ether and a flame-retardant monomer, and carrying out electrostatic spraying to prepare polyamide acid microspheres; dehydrating and drying the polyamide acid microspheres to obtain polyimide microspheres; performing etching-acidification on the polyimide microspheres to prepare carboxylated polyimide microspheres; allyl phosphoric acid and acrylic acid are copolymerized and grafted on the surface of a polyethylene film to prepare a modified polyethylene film; and coating the surface of the modified polyethylene film with the carboxylated polyimide microspheres to prepare the fireproof flame-retardant battery diaphragm. The prepared fireproof flame-retardant battery diaphragm has excellent flame retardance, wetting performance and thermal stability.

The invention discloses a water treatment filtering material and a preparation method thereof, and relates to the technical field of water treatment. When the water treatment filtering material is prepared, alkaline lignin, epichlorohydrin and triethylenetetramine are subjected to a reaction through a reverse suspension cross-linking technology, and lignin porous microspheres are prepared; carrying out reaction on the lignin porous microspheres and picolinamide ligands to obtain modified lignin porous microspheres; 3-mercaptopropyltriethoxysilane and titanium dioxide are subjected to a reaction, and modified titanium dioxide is prepared; the preparation method comprises the following steps: reacting pyromellitic dianhydride, 1, 4-diaminobutylene and 4 ', 4-diaminodiphenyl ether to prepare functionalized polyamide; the functional polyamide, the modified lignin porous microspheres and the modified titanium dioxide are prepared into a spinning solution, and a polyamide membrane is prepared through electrostatic spinning; and carrying out liquid reaction on bromohexane on the polyamide membrane to obtain the water treatment filtering material. The prepared water treatment filtering material has excellent antibacterial property, heavy metal adsorption property, dye removal property and mechanical property.

This invention discloses an MPP pipe for power cables and its preparation method, relating to the field of polymer materials technology. The invention comprises, by weight, 80-90 parts of a toughening nucleating agent; 40-45 parts of an insulating nucleating agent obtained by in-situ composite and gradient temperature imidization treatment of a polyamic acid prepolymer prepared from hexagonal boron nitride nanosheets (prepared by surface modification with dopamine hydrochloride, followed by modification with octyltriethoxysilane) to obtain a silanized boron nitride suspension; 40-45 parts of melamine cyanurate; 2.1-2.4 parts of an antioxidant; 2.6-3 parts of a light stabilizer; 8-9 parts of a lubricant; and 1340-1500 parts of polypropylene. The introduction of the toughening nucleating agent and insulating nucleating agent in this invention effectively improves the flame retardancy, low-temperature rigidity-toughness balance, and aging resistance of the MPP pipe.

The invention discloses a flame-retardant heat-insulating aluminum foil reinforced composite material and a preparation method thereof, and belongs to the technical field of aluminum foil reinforced composite materials. The flame-retardant heat-insulating aluminum foil reinforced composite material prepared by the invention sequentially comprises an aluminum foil layer, a reinforced net, kraft paper and a flame-retardant adhesive layer for bonding the aluminum foil layer and the reinforced net and bonding the reinforced net and the kraft paper from bottom to top, the flame-retardant adhesive layer comprises the following raw material components: a dianhydride monomer, an amine monomer and a heat-insulating filler; the amine monomer comprises 4, 4 '-diaminodiphenyl ether, flame-retardant diaminobenzimidazole and 4-aminobenzonitrile, the heat-insulating filler is prepared from hydroxyapatite nanowires, montmorillonite nanosheets and aminated polyvinyl alcohol, and the flame-retardant heat-insulating aluminum foil reinforced composite material prepared by the preparation method disclosed by the invention is relatively good in flame retardance and heat insulation.

The application provides a porous carbon nanofiber electrocatalyst loaded with cobalt / lanthanum hydroxide heterojunction and a preparation method. The preparation method comprises the following steps: adding 4,4-diamino diphenyl ether and pyromellitic dianhydride into a solvent, uniformly mixing, and preparing a polyamide acid precursor spinning solution; electrospinning the prepared polyamide acid precursor spinning solution to prepare polyamide acid nanofibers; immersing the prepared polyamide acid nanofibers in a mixed metal salt solution containing cobalt salt, lanthanum salt and zinc salt to prepare polyamide acid nanofiber precursors loaded with metal ions; and performing programmed temperature heat treatment on the prepared polyamide acid nanofiber precursors loaded with metal ions in a protective atmosphere to prepare the porous carbon nanofiber electrocatalyst loaded with cobalt / lanthanum hydroxide heterojunction. The prepared porous carbon nanofiber electrocatalyst loaded with cobalt / lanthanum hydroxide heterojunction has excellent electrochemical oxygen reduction reaction and oxygen evolution reaction bifunctional catalytic activity.

The invention belongs to the technical field of polyimide materials, and particularly relates to an interpenetrating network type polyimide material as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out first polycondensation on pyromellitic dianhydride and 4, 4 '-diaminodiphenyl ether to obtain first polyamide acid; performing first cross-linking on the first polyamide acid under the action of a first cross-linking agent to obtain a first cross-linked network; carrying out second polycondensation on the amino-terminated poly (dimethyl siloxane) and 4, 4 '-(hexafluoroisopropenyl) diphthalic anhydride to obtain second polyamide acid; mixing the first polyamic acid and the second polyamic acid for pre-reaction, and then adding a second cross-linking agent for second cross-linking to obtain a precursor solution; and carrying out imidization on the precursor solution to obtain the interpenetrating network type polyimide material. The interpenetrating network type polyimide material obtained by the preparation method provided by the invention realizes synergistic enhancement of strength and toughness.

The present application relates to the technical field of aromatic polyamide polymer, in particular to a modified poly-p-phenyleneterephthalamide fiber with high elongation at break and a preparation method thereof.The present application introduces a small amount of 3,4'-diamino diphenyl ether and a fourth monomer containing a bis-amino phenoxy functional group during polymerization, and controls the molar ratio of the third monomer and the fourth monomer in the total amount of diamine monomer, thereby to a certain extent, the rigid molecular chain structure of the conventional p-aramid is destroyed, while the breaking strength of the fiber is maintained, the elongation at break of the polymer fiber is enhanced, the modified poly-p-phenyleneterephthalamide can still be prepared by dry spraying wet spinning process, the cost of building a new production line in the factory is saved, the process conditions and parameters are optimized, the fiber with stable elongation at break index is obtained, and the prepared fiber has an elongation at break of more than 3.6%.

The present invention provides a polyimide film comprising, as polymeric units, dianhydride monomers comprising pyromellitic dianhydride (PMDA), and diamine monomers comprising 4,4'-methylenedianiline (MDA), meta-phenylenediamine (MPD), 4,4'-diaminodiphenyl ether (ODA), and para-phenylenediamine (PPD), the tensile strength and percent elongation of the polyimide film being 180 MPa or greater and 90% or greater, respectively.

The invention discloses preparation and application of a double-sided aluminized polyimide film for ultralow-temperature multilayer vacuum insulation, and relates to the technical field of polyimide film preparation. The invention relates to an ultralow-temperature multilayer double-sided aluminized polyimide film for vacuum heat insulation, which consists of a polyimide base film and aluminized layers formed on two surfaces of the polyimide base film through a vacuum evaporation method, the polyimide base film is prepared from the following raw materials in parts by mass: 100 parts of pyromellitic dianhydride, 4, 4 '-diaminodiphenyl ether, 5-15 parts of a low-temperature-resistant modifier, 3-8 parts of nano silicon dioxide filler, 0.5-2 parts of a flatting agent, 0.5-1.5 parts of an anti-aging agent, 3-6 parts of a silane coupling agent and 5-15 parts of polyvinyl chloride. The anti-aging agent with a specific structure is adopted, the phenolic hydroxyl group and the benzotriazole structure have a synergistic effect, free radicals can be captured, ultraviolet rays can be absorbed, the compatibility with a polyimide matrix is good, precipitation at low temperature is avoided, the problems that a traditional anti-aging agent is poor in low-temperature dispersion and prone to failure are solved, and the service life of the film is prolonged.

The application discloses a kind of drying device of diaminodiphenyl ether, belong to chemical production technical field, by moving gear in the center of carousel can revolve while rotating, moving gear is rotated by deflection shaft and is guided to the opening at the bottom of feed hopper Multiple material pieces, diaminodiphenyl ether material inside feed hopper can be uniformly guided in the process of rotation and make it fall into drying box, in the process of discharging, because discharge hopper revolves around the center of drying box, so that material piece can uniformly guide material into drying box from multiple directions, cooperate microwave heater and work, microwave can directly penetrate diaminodiphenyl ether material, so that water molecule inside material rapidly vibrates and generates heat, realize inside and outside heating simultaneously, by uniformly feeding to multiple directions inside drying box and carrying out microwave heating, prevent diaminodiphenyl ether material from appearing agglomeration phenomenon, improve heat transfer efficiency and drying effect.

The invention relates to a high-wear-resistance modified phenolic resin material for a guide ring and a preparation process thereof. The high-wear-resistance modified phenolic resin material for the guide ring is prepared from the following raw materials in parts by mass: 100 parts of linear phenolic resin, 20-35 parts of a polyimide prepolymer, 20-45 parts of a reinforcement, 10-25 parts of a wear-resistant filler, 1-3 parts of a silane coupling agent and 8-12 parts of a curing agent, the polyimide prepolymer is prepared by reacting pyromellitic dianhydride with 4, 4 '-diaminodiphenyl ether. The high-wear-resistance modified phenolic resin material for the guide ring, prepared by the invention, has excellent high-temperature wear resistance.

This invention discloses a fire-retardant battery separator, its preparation method, and a fire-retardant battery, relating to the field of battery separator technology. In preparing the fire-retardant battery separator, this invention involves reacting a mixture of diglyceride borate and trimellitic anhydride chloride to obtain a flame-retardant monomer; polymerizing 4,4'-diaminodiphenyl ether and the flame-retardant monomer, followed by electrostatic spraying to obtain polyamic acid microspheres; dehydrating and drying the polyamic acid microspheres to obtain polyimide microspheres; etching and acidifying the polyimide microspheres to obtain carboxylated polyimide microspheres; grafting propylene-based phosphoric acid and acrylic acid copolymers onto the surface of a polyethylene film to obtain a modified polyethylene film; and coating the carboxylated polyimide microspheres onto the surface of the modified polyethylene film to obtain the fire-retardant battery separator. The fire-retardant battery separator prepared by this invention exhibits excellent flame retardancy, wetting, and thermal stability.

The invention relates to a wide-temperature-range high-moisture-resistance piezoelectric damping material and a preparation method thereof.The wide-temperature-range high-moisture-resistance piezoelectric damping material is prepared from, by weight, 80-90 parts of fluorine-containing modified polyimide precursor, 5-12 parts of MXene-CNT heterogeneous conductive filler, 3-8 parts of hydrophobic modified silicon dioxide and 0.3-1.5 parts of cross-linking agent; wherein the fluorine-containing modified polyimide precursor is prepared by copolymerization of 4, 4 '-diaminodiphenyl ether, pyromellitic dianhydride and 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, and the fluorine-containing modified polyimide precursor is prepared by copolymerization of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane; the hydrophobic modified silicon dioxide is obtained by modifying silicon dioxide through gamma-methacryloxy propyl trimethoxy silane; the cross-linking agent is trimesoyl chloride. The piezoelectric damping material disclosed by the invention is good in low-temperature toughness and has long-term stable moisture-proof performance.

The application provides a wear-resistant enameled copper wire and a preparation method thereof, and belongs to the technical field of enameled copper wires.The preparation method comprises the following steps: repeatedly coating wear-resistant paint on a copper wire and curing the wear-resistant paint into a paint film, and then cooling and winding the copper wire to obtain the wear-resistant enameled copper wire.The preparation method of the wear-resistant paint comprises the following steps: adding 4,4'-diamino-4"-hydroxytriphenylmethane and 2,2-bis-[4-(4-aminophenoxy)phenyl]propane into a polymerization bottle, adding N,N-dimethylacetamide, stirring and dissolving, adding 3,3',4,4'-benzophenonetetracarboxylic dianhydride, stirring and polymerizing, and obtaining a polyamic acid solution one; adding 4,4'-diamino diphenyl ether into the polymerization bottle, adding N,N-dimethylacetamide, stirring and dissolving, adding pyromellitic dianhydride, stirring and polymerizing, and obtaining a polyamic acid solution two; adding the polyamic acid solution one and the polyamic acid solution two into the polymerization bottle, adding a silane coupling agent, stirring, adding N,N-dimethylacetamide and a peroxide initiator, and stirring uniformly to obtain the wear-resistant paint; and the wear resistance of the wear-resistant enameled copper wire can be effectively improved.

The invention relates to the technical field of composite materials, in particular to a low-temperature medium leakage prevention carbon fiber composite material with self-repairing and self-adaptive sealing functions and a preparation method and application thereof. The preparation method of the composite material comprises the following steps: S1, adding 4, 4 '-diaminodiphenyl ether and 3, 5-diaminobenzoic acid-3-trifluoromethyl phenyl ester into dimethylacetamide, stirring, then adding 4, 4'-hexafluoroisopropyl phthalic anhydride, stirring, heating to room temperature, and continuously stirring to obtain fluorine-containing side chain polyimide; adding an MXene dispersion liquid into the fluorine-containing side chain polyimide to obtain a polyimide adhesive film layer, S2, preparing a carbon fiber bearing layer; s3, adding an aromatic disulfide bond repairing agent into water, then adding isophorone diisocyanate and polyether amine for reaction, and then mixing with polyethylene glycol terephthalate to prepare a self-repairing impermeable layer; s4, preparing a double-layer gradient film; and S5, preparing the carbon fiber composite material.

The invention discloses a high-elongation ternary aramid fiber and a preparation method and application thereof.The preparation method comprises the steps that 3, 4 '-diaminodiphenyl ether and p-phenylenediamine are jointly dissolved in a composite solvent composed of N-methyl pyrrolidone and calcium chloride according to a specific molar ratio, and the high-elongation ternary aramid fiber is obtained through a multi-stage temperature control and stepped rotating speed twin-screw continuous polycondensation process; adding paraphthaloyl chloride step by step to realize controllable polymerization so as to form a polymer solution; and neutralizing, defoaming and filtering the polymer solution to obtain a spinning solution, and carrying out dry-jet wet spinning to obtain the ternary aramid fiber. According to the method, continuous polymerization and solution dry-jet wet spinning are combined, and the solid content of the spinning solution is increased, so that the fiber has the advantages of high strength and high toughness, the spinning speed is increased, and the production cost is reduced. A flexible ether bond is introduced into a terpolymer structure, so that the original highly regular crystal structure of the para-aramid fiber is destroyed, and a molecular chain is easier to relatively slide and deform when being stressed, so that the extensibility of the fiber is improved.

This invention discloses polyimide, its preparation method, and polyester electronic adhesive. This invention provides a polyimide whose polymerizing monomers include dianhydride monomers and diamine monomers, wherein the dianhydride monomer is selected from one or more of 4,4'-(4,4'-isopropyldiphenoxy)bis(phthalic anhydride), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxybis(phthalic anhydride), and 2,3,3',4'-biphenyltetracarboxylic dianhydride; and the diamine monomer is selected from one or more of aminophenyl sulfone, 1,3-bis(4'-aminophenoxy)benzene, 2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 4,4'-bis(3-aminophenoxy)diphenyl sulfone, 1,3-cyclohexanedimethylamine, 4,4'-diaminodiphenyl ether, dimericadiamine, and trimericadiamine. The polyimide of this invention can modify polyester or epoxy systems, significantly improving flame retardancy and adhesive peel strength. The coating process involves evaporation at relatively low temperatures, and the solvent in the system has a low boiling point, meeting the requirements of existing processes.

The application discloses a kind of reinforced toughened impact resistant wear-resistant anticorrosion integrated coating material and preparation method thereof, it is related to high polymer composite material and functional coating technical field, method includes: providing hexafluorocyclotriphosphazene and vanillin, mixing, carries out first reaction, obtains first reactant;Providing 4,4'-diamino diphenyl ether and 3,3',4,4'-benzophenone tetracarboxylic dianhydride, mixing, carries out second reaction, obtains second reactant;Providing hydroxyl-terminated polydimethylsiloxane and 4,4'-diphenyl methane diisocyanate, with second reactant is mixed, carries out third reaction, obtains third reactant;Providing iron salt, with first reactant and third reactant are mixed, carries out solidification treatment, obtains coating material;The reinforced toughened impact resistant wear-resistant anticorrosion integrated coating material obtained will be integrated in single layer coating with the functions such as reinforcement, toughening, impact resistance, wear resistance, corrosion resistance, etc., with excellent wear resistance and anticorrosion performance and intrinsic flame-retardant radiation resistance characteristics.

This invention proposes a polyimide film, its preparation method, and its applications, relating to the field of thin film materials. By weight, it comprises the following raw materials: 50-100 parts dimethylformamide, 5-10 parts diaminodiphenyl ether, 10-20 parts phenylenediamine, 1-2 parts core-shell structured silica-alumina particles, 25-30 parts pyromellitic dianhydride, 1-2 parts organically modified montmorillonite, 1-2 parts aminated thermally conductive particles, 50-100 parts acetic anhydride, and 5-10 parts pyridine; wherein the core-shell structured silica-alumina particles are a composite material with polydopamine as the shell and nano-silica and nano-alumina as the core; the organically modified montmorillonite is obtained by intercalation modification of montmorillonite with an organic compound containing hydroxyl groups; the aminated thermally conductive particles are obtained by graft modification of nitrides with an organic compound containing amino groups. It exhibits good high-temperature resistance, high-pressure breakdown resistance, and thermal conductivity, as well as high mechanical strength and long service life.

The invention relates to a method for preparing 3, 4 '-diaminodiphenyl ether through efficient hydrogenation, and belongs to the technical field of fine chemical engineering. The method for preparing 3, 4 '-diaminodiphenyl ether comprises the following steps: dissolving 3-amino-4'-nitrodiphenyl ether in an organic solvent to obtain a to-be-hydrogenated liquid, adding the to-be-hydrogenated liquid and hydrogen into a multilayer tubular reactor for hydrogenation reaction to obtain a hydrogenated crude product liquid, then adding an alkaline substance, adding water for washing, and carrying out solid-liquid separation to obtain 3, 4 '-diaminodiphenyl ether, the multi-layer tubular reactor comprises a preheating dispersion layer, a catalyst layer and a filtering stable output layer from top to bottom; the preheating and dispersing layer comprises a coarse dispersing and preheating layer and a fine dispersing and preheating layer from top to bottom; the catalyst layer comprises a nitro activation catalyst layer and a side reaction inhibition catalyst layer from top to bottom; the filtering stable output layer comprises a filtering cooling layer and a stable output layer from top to bottom. The method is simple to operate and controllable in process, the production efficiency is improved, and the product purity and yield are improved.

The application provides a low-yellowing fluorine-free semi-alicyclic polyimide composition and a preparation method thereof, and relates to the technical field of polyimide preparation.The semi-alicyclic polyimide composition is prepared by polymerization reaction of diamine and dianhydride; the diamine comprises first diamine and second diamine; the first diamine is 4,4'-diamino diphenyl ether-2,2'-disulfonic acid and / or 4-(4-aminophenoxy)-2,6-dimethyl aniline; the second diamine is 4,4'-diamino dicyclohexyl methane and / or 3,3'-dimethyl-4,4'-diamino dicyclohexyl methane; and the dianhydride is fluorine-free dianhydride. The semi-alicyclic polyimide composition prepared by the application significantly improves the optical performance of the polyimide film prepared therefrom, and the anti-yellowing effect is significantly improved.

The present application relates to the technical field of high polymer materials, and particularly relates to a preparation method of wear-resistant / low-dielectric PTFE composite material based on interface functionalization. Ammonia / hydrogen mixed gas is used to perform low-temperature plasma treatment on PTFE powder; then the activated PTFE powder is dispersed in an aqueous solution containing ammonium perfluorooctanoate and 4-dimethylamino pyridine; then an organic phase of pyromellitic acid dichloride and an aqueous phase of 4,4'-diamino diphenyl ether are synchronously added dropwise to implement in-situ interface polymerization on the surface of PTFE particles to generate a polyamide acid ammonium salt coating layer; finally, through programmed temperature rising, the coating layer is converted into polyimide, and under the action of hot pressing, a composite material with PTFE as a matrix and a three-dimensional network of polyimide nanofibers penetrating through the inside is formed. The interface bonding force between the reinforcing phase and the PTFE matrix is significantly enhanced, so that the composite material simultaneously has excellent wear resistance, low dielectric constant, high mechanical strength and thermal stability.

The invention discloses polymer PI fiber heat preservation cotton and a preparation method thereof.The heat preservation cotton comprises an inner layer, a middle layer and an outer layer, the inner layer comprises PI fibers and polyvinyl alcohol fibers, the middle layer comprises the PI fibers and skin-core composite fibers, and the outer layer comprises the PI fibers, aramid fibers and low-melting-point fibers; the middle layer PI fiber is a modified PI fiber, and the preparation of the modified PI fiber comprises the following steps: under a nitrogen protection atmosphere, polymerizing pyromellitic dianhydride and 4, 4 '-diaminodiphenyl ether in N, N-dimethylacetamide to obtain a polyamide acid solution; adding phenylacetylene-terminated hyperbranched polysiloxane, fluorinated graphene oxide, a surfactant and a pore-forming agent into the polyamide acid solution, and reacting to obtain a modified polyamide acid spinning solution; and carrying out dry spinning and thermal forming treatment on the modified polyamide acid spinning solution to obtain the modified PI fiber. The obtained heat preservation cotton has the characteristics of heat preservation, washing resistance and comfort.

The invention discloses a preparation method of an optical fiber for a high-temperature non-fading and non-migration optical cable, and relates to optical fibers. According to the invention, the curing monomer and 3-aminopropyl methyl dimethoxy silane are added into the acrylic resin of the inner coating layer, and the additive does not contain small molecular active substances, so that the migration phenomenon is avoided; and the amino siloxane can enhance the adhesion between the high-temperature-resistant acrylate layer and the polyimide layer. Secondly, maleic anhydride and 4, 4 '-diaminodiphenyl ether are used as reaction raw materials to synthesize a diamine monomer containing a bisimide element, a thermosetting polyimide film with a molecular main chain containing a dynamic imine bond is prepared through an amine-aldehyde condensation reaction, a primary amine group in an amino silane coupling agent is utilized, and the dynamic imine bond in the main chain of the thermosetting polyimide film is removed; the imine reversible bond exchange reaction is promoted, self-repairing is achieved, large-area layered stripping of a coating is repaired after the optical fiber is used for a long time, and the high temperature resistance of the optical fiber is improved. The optical fiber prepared by the invention has a high-temperature stable effect.

This invention relates to a polyimide material and its preparation method, belonging to the field of polymer materials technology. The invention uses a macromolecular diamine monomer containing PEG segments and 4,4'-diaminodiphenyl ether as a compounded diamine monomer, reacting it with a dianhydride monomer compounded with 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride and 3,3',4,4'-biphenyl tetracarboxylic dianhydride to prepare a polyimide with carboxyl groups in its side chains. Then, the polyimide with carboxyl groups in its side chains is grafted with a photosensitive compound to prepare a photosensitive polyimide material. The PEG-based macromolecular diamine provides excellent solubility, film-forming properties, and low-temperature flexibility; the rigid aromatic diamine improves mechanical strength, thermal stability, and pattern fidelity; the ether-bonded ODPA ensures solubility and uniform crosslinking; and the biphenyl-type BPDA increases modulus, reduces water absorption, and improves resolution.

The invention belongs to the technical field of stealth coatings, and relates to a PI-based porous wave-absorbing coating based on flame spraying and a preparation method of the PI-based porous wave-absorbing coating. The PI-based porous wave-absorbing coating takes porous polyimide as a continuous matrix, and neodymium-doped barium ferrite and multi-walled carbon nanotubes are dispersed in the porous polyimide matrix; through a flame spraying method, spraying suspension liquid formed by 4, 4 '-diaminodiphenyl ether, pyromellitic dianhydride, neodymium-doped barium ferrite, multi-walled carbon nanotubes and an organic solvent is sprayed on the surface of a substrate. The PI-based porous wave-absorbing coating provided by the invention has excellent broadband strong absorption characteristic, can keep stable wave-absorbing performance in a wider thickness range, shows remarkable thickness insensitivity, and greatly reduces the precision requirement on thickness control of the coating.

The polyamic acid is a reaction product of an acid dianhydride component and a diamine component. The acid dianhydride component includes biphenyltetracarboxylic dianhydride. In addition, the diamine component does not include a fluorine atom and a diamino diphenyl ether, and includes 4-aminophenyl 4-aminobenzoate.

The invention relates to the technical field of organic chemical synthesis, in particular to a preparation method of 3, 4 '-diaminodiphenyl ether.The preparation method comprises the steps that S1, under inert gas and in a first solvent, m-dinitrobenzene and p-acetamidophenol are subjected to a heating reaction under the condition of a weak base catalyst, and 3-nitro-4-acetamido diphenyl ether is prepared; s2, in a second solvent, the 3-nitro-4-acetamido diphenyl ether is subjected to a hydrogenation reduction reaction, and 3-amino-4-acetamido diphenyl ether is prepared; and S3, dissolving the 3-amino-4-acetaminodiphenyl ether in an alcohol solvent system, adding alkali and water, controlling the reaction temperature, carrying out a hydrolysis reaction, and after the reaction is finished, carrying out post-treatment to obtain the 3, 4 '-diaminodiphenyl ether. The preparation method provided by the invention has the advantages of easily available raw materials, low price, good selectivity and high product yield, and is more suitable for industrial production by comprehensively considering economical efficiency and safety.

The invention relates to the field of high polymer materials and building materials, in particular to a high-flame-retardant TPU elastomer and a preparation method thereof and an anti-collision composite wallboard, the TPU elastomer is prepared from TPU, SEBS, PPO, coated flame-retardant particles and other raw materials, each coated flame-retardant particle comprises a core layer and a shell layer, and the core layer comprises flame-retardant filler; and the shell layer is prepared from the following raw materials: 4, 4 '-diaminodiphenyl ether, phosphonitrilic chloride trimer and epoxy silane modified phosphate. The TPU elastomer has high flame retardance, high impact resistance and high elasticity due to the coated flame-retardant particles prepared by coating the organic flame retardant with the inorganic particles, and has good anti-collision and flame-retardant properties when being used for the anti-collision composite wallboard.