368 results about "Polyetherimide" patented technology

The invention relates to the technical field of PET geothermal films, and discloses a high-temperature-resistant geothermal film and a preparation method thereof.The high-temperature-resistant geothermal film is obtained through blending extrusion and blow molding of polyethylene glycol terephthalate, carboxyl polyetherimide and modified graphene. The carboxyl polyetherimide contains a benzoate structural unit similar to PET, the carboxyl polyetherimide and the benzoate structural unit form an alloy-like system with good compatibility, the modified graphene is good in dispersity and excellent in compatibility with PET, meanwhile, the modified graphene contains more carboxyl groups, and the carboxyl groups and carboxyl groups of side chains of the carboxyl polyetherimide interact with each other to form hydrogen bonds and the like; the graphene can be uniformly dispersed in a composite system of PET and carboxyl polyetherimide, so that a better reinforcing effect is achieved, and the tensile strength and the elongation at break of the PET composite geothermal film are remarkably improved. After high-temperature thermal aging, the geothermal film is high in retention rate of tensile strength and elongation at break and good in high-temperature resistance.

The invention discloses a modified sodium carboxymethyl cellulose-based binder, and belongs to the technical field of binders for lithium ion batteries. According to the modified sodium carboxymethyl cellulose-based binder, CMC-Na is used as a raw material, and a modifier is added, so that the modified sodium carboxymethyl cellulose-based binder is obtained; the modifier is any one of a mixture of PA (polyamide) and CaCl2 or PEI (polyetherimide). The specific capacity of the prepared C-PEI-10% pole piece is 2249.1 mAh g <-1 > after 100 cycles under the current density of 0.2 C, and a compact SEI layer can be formed on the electrode. The specific capacity of Si-coated C-PA-Ca < 2 + > is 1879.7 mAh g <-1 > after 300 cycles under the current density of 0.5 C, and the capacity retention ratio is 70.85%.

The invention discloses a preparation method of a solvent-resistant nanofiltration membrane with a polydopamine / amino silicon dioxide middle layer, belongs to the technical field of membrane separation, and solves the technical problems of low flux and poor stability of the solvent-resistant nanofiltration membrane. The preparation method of the solvent-resistant nanofiltration membrane with the polydopamine / amino silicon dioxide middle layer comprises the following steps: preparing a polyetherimide-based membrane by a phase inversion method-crosslinking method; preparing amino silicon dioxide nanoparticles by adopting a sol-gel method; preparing a deposition solution containing dopamine, an oxidizing agent and amino silicon dioxide by using a Tris buffer solution; depositing the polydopamine / amino silicon dioxide intermediate layer on the upper surface of the polyetherimide base film; carrying out interfacial polymerization reaction of piperazine and trimesoyl chloride on the surface of the membrane deposited with the middle layer, and carrying out heat treatment to obtain a composite membrane; and immersing the composite membrane into an organic solvent for activation to obtain the solvent-resistant nanofiltration membrane with a polydopamine / amino silicon dioxide intermediate layer. The solvent-resistant nanofiltration membrane constructed by taking polyetherimide as a base membrane, polydopamine / amino silicon dioxide as a middle layer and polyamide as a separation layer has excellent flux and stability, and has a wide application prospect in the aspects of drug separation, organic solvent recovery and the like.

The invention belongs to the field of solid-state batteries, and particularly relates to a solid-state battery and a composite electrolyte, preparation and application thereof, and the preparation method of the composite electrolyte comprises the following steps: dissolving a base membrane polymer with a solvent A to obtain a base membrane solution, and forming the base membrane solution into a wet membrane; pre-forming the wet film in an environment with the humidity of 50-80% RH in advance; soaking the wet film in a solvent B, and forming the wet film into a base film; and compounding the base membrane and a precursor solution for forming the electrolyte, and then carrying out in-situ polymerization to prepare the composite electrolyte, wherein the base membrane polymer comprises at least one of polyether sulfone, sulfonated polyether sulfone and polyetherimide; the solvent B is a mixed solvent of water and C1-C4 alcohol, and the volume ratio of the water to the C1-C4 alcohol is 1: (0.1-10); the precursor solution is a solution containing a monomer, a plasticizer and electrolytic salt. The method provided by the invention can be used for preparing the solid electrolyte with a special structure and excellent performance such as fast charge stability.

The invention discloses a polyetherimide / polyaryletherketone composite material with high breakdown performance and mechanical toughness as well as a preparation method and application of the polyetherimide / polyaryletherketone composite material, and belongs to the technical field of polyetherimide insulation. The invention solves the problems that the dielectric constant of the polyetherimide can be improved by increasing the use amount of the conductive filler in the prior art, but the breakdown performance of the polyetherimide is reduced, so that the polyetherimide cannot have toughness and high breakdown performance at the same time. According to the invention, polyetherimide and polyaryletherketone are used as raw materials and are mixed by adopting a solution blending method, then a substrate is coated with the mixture, and the polyaryletherketone / polyetherimide / polyaryletherketone composite material is obtained through curing. According to the invention, polyetherimide and polyaryletherketone are well dispersed on a microscopic scale, and the composite material has low dielectric loss of polyetherimide and high toughness of PAEK, and has good dielectric properties and breakdown electrical strength; the material is suitable for the advanced fields of high-energy density capacitors, power electronic devices, aerospace electrical insulation parts, new energy automobile high-voltage systems and the like.

The invention relates to the technical field of wire and cable materials, and discloses a high-temperature-resistant and aging-resistant wire and cable material and a preparation method thereof.The high-temperature-resistant and aging-resistant wire and cable material is prepared from, by weight, modified polyetherimide, silane modified polyolefin, organic montmorillonite, surface modified nanometer aluminum oxide and surface functionalized graphene, an antioxidant, a silane coupling agent and a processing lubricant; the preparation method of the high-temperature-resistant and aging-resistant wire and cable material comprises the following steps: weighing and preparing raw materials; carrying out surface modification treatment on the nanofiller; drying the raw materials; premixing the components; reacting, extruding and granulating; and cooling, bracing and dicing. By adopting the technical scheme of synergistic application of the surface functionalized graphene and the silane modified polyolefin, the technical effect of remarkably improving the thermal stability and the mechanical property of the composite material is achieved, the problem that the performance of a traditional scheme is unstable at high temperature is solved, and the phenomena of filler agglomeration and material degradation are avoided.

The invention relates to an acid-resistant nanofiltration membrane and a preparation method thereof, and relates to the technical field of nanofiltration membranes. The acid-resistant nanofiltration membrane comprises a supporting base layer and a functional layer, the functional layer is formed by interfacial polymerization on the supporting base layer, the supporting base layer comprises a polyetherimide-nanomembrane, raw materials of the functional layer comprise an oil-phase solution and a water-phase solution, the oil-phase solution comprises 1, 3, 5-benzene trisulfonyl chloride and an oil-phase solvent, and the water-phase solution comprises 1, 3, 5-benzene trisulfonyl chloride and a water-phase solvent. The water-phase solution comprises piperazine and a water-phase solvent; the method has the effect of improving the acid resistance of the nanofiltration membrane.

The invention discloses a PC (polycarbonate) and ABS (acrylonitrile butadiene styrene) mixed material and a preparation process in the field of polymer composite materials, and designs two brand-new modified compounds: the first one is a benzoxazine-polysiloxane block copolymer which is prepared by reacting a benzoxazine prepolymer with epoxy terminated polysiloxane and has rigidity, heat resistance, flexibility and toughness; and the other carbon nanotube is an amino-terminated polyetherimide grafted carbon nanotube, and polar interface bridging is realized through covalent grafting of the carboxylated carbon nanotube and amino-terminated polyetherimide. According to the mixed material, PC and ABS are used as main raw materials, the two modified compounds, the antioxidant and the lubricant are added, and the comprehensive performance is improved through the synergistic effect of all the components. The preparation method comprises the following steps: premixing the raw materials at a high speed, carrying out melt blending through a twin-screw extruder, carrying out extrusion granulation, and drying to obtain the target material. And the prepared PC / ABS mixed material has the advantages of strong interface bonding force, low phase separation degree, high toughness and heat resistance, and is suitable for the fields of electronic appliances and the like.

The invention belongs to the technical field of building materials, and particularly relates to an artificial aggregate prepared based on waste concrete and PEI, a preparation method and application. The preparation method comprises the following steps: crushing waste concrete to obtain regenerated micro powder, mixing the regenerated micro powder with cement dry powder to obtain mixed powder, then jointly granulating sand grains, the mixed powder and a PEI aqueous solution to obtain artificial aggregate particles, and finally carbonizing and curing the artificial aggregate particles to obtain the required artificial aggregate. The PEI is introduced in the granulation process of the waste concrete, CO2 and active components in the waste concrete are fully reacted to generate calcium carbonate sediment by utilizing the efficient carbon capture performance of the PEI, pores of the aggregate are effectively filled, the strength, compactness and durability of the recycled aggregate are remarkably improved, and the prepared artificial aggregate has a very good application prospect.

The application discloses a quinoline small molecule blended modified polymer dielectric material and a preparation method and application thereof, and belongs to the technical field of capacitor films. The preparation raw materials comprise quinoline derivatives, polymethyl methacrylate, styrene-methyl methacrylate copolymer, polyetherimide, polypropylene and N-methyl pyrrolidone solution, and the preparation steps comprise blending and film preparation. The blending solution or eutectic mixture is prepared through blending, and the polymer dielectric film is prepared through a flow casting method or bidirectional stretching. The prepared quinoline small molecule blended modified polymer dielectric film has excellent electrical properties, can reduce the leakage current of the polymer material, has high DC breakdown field strength, high energy storage density and low energy loss, and is easy to realize large-scale production.

The invention relates to the field of high polymer materials, and discloses an antistatic polyether-ether-ketone composite material for semiconductor devices, the antistatic polyether-ether-ketone composite material comprises the following raw materials by weight: 60-70 parts of polyether-ether-ketone, 20-30 parts of polyetherimide, 3-5 parts of modified carbon nanotubes, 2-4 parts of nano core-shell particles, 0.5-1 part of a coupling agent, and 0.2-0.5 part of an antioxidant; the modified carbon nanotubes are obtained by acidizing carbon nanotubes and grafting imidazolyl quaternary ammonium salt on the surfaces of the acidized carbon nanotubes; according to the antistatic polyether-ether-ketone composite material, through blending of polyetherimide, the melt viscosity of a composite system can be reduced, the problems that polyether-ether-ketone is high in processing temperature and poor in flowability are solved, and the antistatic performance of the composite material is improved. Through the synergistic interaction of the added modified carbon nanotubes and nano core-shell particles, the material is endowed with excellent mechanical properties, wear resistance and antistatic properties.

The embodiment of the invention provides a carbon fiber sizing agent, a modified carbon fiber, a composite material and a method, and relates to the technical field of carbon fiber surface treatment. The carbon fiber sizing agent comprises the following components: polyetherimide, amino-functionalized ZIF-8 and an organic solvent, wherein the mass of the amino-functionalized ZIF-8 is 1%-10% of the mass of the polyetherimide. According to the carbon fiber sizing agent, the modified carbon fiber, the composite material and the method provided by the embodiment of the invention, the interface bonding strength and the heat resistance of the carbon fiber and the resin matrix in the carbon fiber composite material can be improved.

The invention relates to the field of conductive composite materials and wind power generation, and discloses a light conductive composite material and a lightning protection fan blade made of the light conductive composite material. 2-5% of a multi-walled carbon nanotube; 4-8% of silver-plated short fiber; 2-5% of graphite flakes; 1-3% of boron nitride micro powder; 3-7% of silver conductive paste; 0.5 to 2% of a polyethylene glycol based surface modifier; 1-3% of a silane coupling agent; 0.3 to 1% of a hindered phenol antioxidant; the multi-walled carbon nanotubes are subjected to surface carboxylation modification through a mixed solution of concentrated nitric acid and concentrated sulfuric acid, and are further modified through a polyethylene glycol-based surface modifier. By constructing the multi-scale graded conductive network and improving the heat dispersion performance of the material, efficient conduction and heat dissipation of lightning stroke current are achieved, meanwhile, the requirement for light weight of the fan blade is met, and therefore the defects in the aspects of conductive network stability, heat dispersion performance and preparation technology in the prior art are overcome.

The invention discloses a high-flux nanofiltration membrane for nanofiltration concentration of a lithium carbonate solution and a preparation method of the high-flux nanofiltration membrane, belongs to the technical field of nanofiltration membrane processing, and is used for solving the technical problems of low permeation flux, poor Li < + > rejection rate capability and weak impact resistance of a nanofiltration membrane in the prior art. The preparation method comprises the following steps: adding polyetherimide and dimethyl sulfoxide into a reaction kettle, stirring, raising the temperature of the reaction kettle to 60-70 DEG C, stirring for 5-6 hours to obtain a polyetherimide membrane casting solution, coating a glass plate with the polyetherimide membrane casting solution, and carrying out phase inversion finishing to obtain a porous base membrane; the composite nanofiltration membrane with a Li < + > channel is prepared on the surface of the polyamide-based membrane by adding the crown ether containing the boric acid group and capable of selectively adsorbing Li < + >, the ethylenediamine and the polyethyleneimine through an interfacial polymerization method, so that the permeation flux, the Li < + > rejection rate and the structural strength of the nanofiltration membrane can be further improved, and the service life of the nanofiltration membrane is further prolonged.

The preparation method specifically comprises the following steps: dispersing a certain mass of active hydrogen-containing polymer, hydrolyzable silane polymer, polyetherimide, hydrophobic nanoparticles and a surfactant in a mixed solvent to prepare a membrane casting solution, carrying out blade coating to form a membrane, and carrying out first-stage and second-stage acidic solution treatment to obtain the waterproof breathable membrane. The waterproof breathable film is finally obtained by inducing the shrinkage effect of the active hydrogen-containing polymer, the phase separation of polyetherimide and the directional migration of nanoparticles. The prepared waterproof breathable film has high breathability and degradability, the process is simple and efficient, and the waterproof breathable film is suitable for large-scale production.

The invention provides a carbon nanotube-polyetherimide grafted carbon fiber / nylon composite material as well as a preparation method and application thereof, and belongs to the technical field of composite materials. The preparation method comprises the following steps: mixing polyetherimide, a condensing agent, acidified carbon fibers and an organic solvent, and carrying out first amidation reaction to obtain polyetherimide grafted carbon fibers; mixing the polyetherimide grafted carbon fibers, a condensing agent, acidified carbon nanotubes and an organic solvent, and carrying out a second amidation reaction to obtain carbon nanotube-polyetherimide grafted carbon fibers; the carbon nanotube-polyetherimide grafted carbon fibers and nylon resin are subjected to melt blending to obtain the carbon nanotube-polyetherimide grafted carbon fiber / nylon composite material, so that the carbon nanotubes are uniformly dispersed on the surfaces of the carbon fibers, the reinforcing effect of the carbon nanotubes is fully exerted, the nanoscale roughness of the surfaces of the carbon fibers is also increased, and the carbon nanotube-polyetherimide grafted carbon fiber / nylon composite material is prepared. The multi-level reinforcement from micron level to nano level is realized, and the mechanical property of the composite material is obviously improved.

The application provides a photoresist waste liquid recycling device and process, by adding hydrochloric acid to the photoresist waste liquid in the acidification precipitation tank in the pretreatment module to adjust the pH value, the linear phenolic resin precipitation rate reaches more than 95%, and the linear phenolic resin can be used again to the production stage of the photoresist after centrifugal separation, a compound coagulant containing sulfide and polyaluminum chloride is added to the heavy metal capture tank in the pretreatment module, and the removal rate of heavy metal ions reaches 99.5%; then the photoresist fragments are separated by using an ultrafiltration device, and the diatomite modified by NaOH and polyetherimide is used for adsorption and decolorization, then two-stage vacuum distillation process is used to realize the recovery of high-purity solvents in the photoresist waste liquid, finally, the remaining residue is polymerized and cured by ultraviolet radiation, and the solid fuel with high heat value can also be prepared, so that the 'zero emission' and resource full recovery of the photoresist waste liquid are realized, and the treatment cost and environmental risk are significantly reduced.

Disclosed herein are multilayer composite laminates comprising continuous fibers and a polymer matrix comprising a poly(arylene sulfide) (PAS) polymer, a polyetherimide (PEI) polymer, and a polyamide-imide (PAI) polymer.

The application belongs to the field of high dielectric constant (ε r ), low dielectric loss (tan delta) composite dielectric material, and particularly relates to a preparation method of a modified polyether sulfone / polyether imide polymer alloy. g Polymer polyether imide is blended, the mixture is added into DMAc at a solid content of 15%-20%, is stirred and dissolved at 80 DEG C, then a thin film is prepared on a glass plate by using a scraping coating method, finally the glass plate is transferred to a vacuum oven, is kept at 55 DEG C overnight, is kept at 100 DEG C for 3-5 hours, and is cured at 180 DEG C for 3-5 hours, thereby a blended film is prepared, wherein the mass fraction of the modified polyether sulfone in the mixture is 1wt%-30wt%. The modified polyaryl ether sulfone polymer segment with a side chain branched large dipole moment polar group is used as an organic filler, a small amount of addition can greatly reduce the dielectric loss, the operation is simple, the spectrum is good, and the influence on T g is very small, and the dispersion and interface problems of inorganic fillers are avoided.

The present invention relates to a kind of water-resistant honeycomb activated carbon and preparation method thereof, belong to the technical field of activated carbon. A kind of preparation method of water-resistant honeycomb activated carbon comprises the following steps: 1) after heating and firing the coconut shell raw material after cleaning; 2) under nitrogen atmosphere, cyano-modified polyphenylene sulfide, polyetherimide, accelerator and activated carbon powder are mixed uniformly and then heated to react, cooled and washed, and dried; 3) N, N-dimethylacetamide is added to activated carbon intermediate and heated and extracted, solid is filtered and taken, put into anhydrous ethanol and soaked, solid is filtered and taken, after washing; 4) modified activated carbon is placed in anhydrous ethanol, tetrabutyl titanate is added and stirred and mixed, ferric nitrate solution is added by spraying under stirring, ultrasonic treatment is carried out after the addition of materials is completed, solid is filtered and taken, and microwave drying is carried out after centrifugation. The water-resistant honeycomb activated carbon prepared by the present invention has higher stability, water resistance and adsorption.

The invention relates to the technical field of composite boards, in particular to a composite laminated board with excellent flame retardant property and mechanical property. In order to solve the problem that in the prior art, reinforcing layers are all made of carbon fiber materials, and cost is high, the composite laminated board with the excellent flame retardant property and mechanical property is provided and comprises a thermoplastic resin layer, a carbon fiber cloth layer and a glass fiber cloth layer, and the thermoplastic resin layer and the carbon fiber cloth layer are arranged adjacently. The carbon fiber cloth layer and the glass fiber cloth layer are adjacently arranged, and the thermoplastic resin layer comprises polyetherimide and polycarbonate. According to the invention, the glass fiber cloth layer with lower cost is used for replacing part of the carbon fiber cloth layer for compounding to form the composite laminated board, so that the overall manufacturing cost of the composite laminated board is reduced, and meanwhile, the prepared composite laminated board can still maintain relatively ideal performance in flame-retardant effect and mechanical strength.

The invention discloses an anti-biofilm nano composite material added with resveratrol and a preparation method of the anti-biofilm nano composite material. According to the method, ferric trichloride hexahydrate, trisodium citrate, sodium acetate, polyetherimide, resveratrol and hyaluronic acid are used as raw materials, modified magnetic Fe3O4 nanoparticles with positive charges are prepared through a hydrothermal method, carbon dots derived from a resveratrol and hyaluronic acid mixture are introduced, and the magnetic Fe3O4 nanoparticles with positive charges are prepared. The anti-biofilm nano composite material added with the resveratrol is prepared. The nano composite material disclosed by the invention can be attached to a biological membrane, so that the loss is reduced in a transfer process, the effective utilization rate of a medicine is remarkably improved, and excellent magnetic property, antibacterial property and biological membrane resistance are shown.

The invention provides a fiber woven structure dielectric film for a high-energy-storage-density capacitor and a preparation method, and aims to solve the problem that the dielectric constant and the breakdown strength of a polymer-based dielectric material are difficult to improve at the same time, so that the energy storage density cannot meet the requirements of a high-power-density energy storage capacitor. Polyetherimide / polyvinylidene fluoride-hexafluoropropylene core-shell structure fiber with a core-shell structure is prepared through a coaxial electrostatic spinning technology, a composite film is formed through lamination and hot pressing, a woven structure is regulated and controlled by adjusting the composition content of the core-shell fiber, the fiber orientation stacking direction and the stacking layer number, the mechanical strength of the film is enhanced, a deep trap is formed to capture carriers, and the performance of the film is improved. And a high dielectric constant is maintained by utilizing interface polarization, and the energy density is comprehensively improved.

The application belongs to the field of membrane material preparation, and discloses a preparation method of a natural gas dehydration membrane, the natural gas dehydration membrane and application thereof. The preparation method comprises the following steps: S1, preparing a mixed solution, wherein the mixed solution comprises polyetherimide, water wheel phenol and a solvent; S2, coating the mixed solution obtained in step S1 into a film; S3, placing the film obtained in step S2 on a substrate or a cold table at-10 to-2 DEG C for 1 to 10 min; S4, placing the film obtained in step S3 at a temperature of 30 to 45 DEG C for 2 to 5 min; S5, placing the film obtained in step S4 into a coagulation solution containing 4-methyl catechol for solidification; and S6, placing the film obtained in step S5 into a pyrrole aqueous solution for immersion, thereby obtaining the natural gas dehydration membrane. The natural gas dehydration membrane prepared by the application has high water permeability and a H2O / CH4 separation coefficient, and can be used in the dehydration process before natural gas transportation.

The present application belongs to the field of polymer materials, and particularly relates to a self-toughened epoxy resin with high temperature resistance and a preparation method thereof. The modifier is a multifunctional epoxy resin containing a polyetherimide structure. The modifier is dissolved and blended with a bisphenol A type epoxy resin. The curing agent comprises one or more of methyl nadic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, dodecenyl succinic anhydride and pyromellitic anhydride. The curing accelerator comprises one or more of dimethylaminomethylphenol, ortho-hydroxybenzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, triethylamine and triethanolamine. The multifunctional epoxy resin containing a polyetherimide structure not only has good solubility in the bisphenol A type epoxy resin, but also can participate in the curing reaction of the bisphenol A type epoxy resin, so that the toughness and temperature resistance of the bisphenol A type epoxy resin can be significantly improved.

The invention discloses a method for preparing a gas-liquid separation membrane and its application in a purge gas reactor; It belongs to the field of gas-liquid separation membrane technology; It includes the steps of: placing a resin matrix, a cross-linking agent, a chemical auxiliary agent and a solvent in a container, stirring and mixing uniformly, obtaining a resin composition, then coating the resin composition on a release film, peeling off, and obtaining a gas-liquid separation membrane; Wherein, the resin matrix is ​​at least one of polyethersulfone, polydimethylsiloxane, polyetherimide, polyvinylidene fluoride, polyacrylic resin, epoxy resin, and modified polyurethane resin; Modified polyurethane is prepared by 2-hydroxypropionate-modified polyurethane resin. The gas-liquid separation membrane prepared by the present invention has higher resistance to hydraulic pressure and air permeability and excellent water resistance, wear resistance and mechanical properties, and can be preferably applied to a purge gas reactor.

This invention discloses a high-wear-resistant polyetherimide composite material, its preparation method, and its applications. The high-wear-resistant polyetherimide composite material comprises the following components by weight: 60-90 parts polyetherimide, 10-40 parts polyketimide, 1-5 parts antioxidant, 10-20 parts hollow glass microspheres, and 5-10 parts toughening agent. The high-wear-resistant polyetherimide composite material is prepared by compounding the two polymers and simultaneously adding wear-resistant additives. The composite material prepared by this invention achieves a Rockwell hardness of over 105 and possesses excellent mechanical properties, making it suitable for application in high-temperature and wear-resistant aerospace fields.

The invention belongs to the technical field of macromolecular ultrafiltration membranes, and particularly relates to an ultrafiltration membrane as well as a preparation method and application thereof. Polyetherimide is used as an effective component of an ammonolysis solution, amino groups distributed on a molecular chain of polyetherimide at intervals and polyester in a membrane casting solution are subjected to ammonolysis reaction to form a moderate cross-linked structure, and meanwhile, the viscosity of a polymer solution is regulated and controlled to a proper range. The dual action promotes the membrane surface to form a complete ultrathin compact skin layer without defects, so that the ultrafiltration membrane is endowed with excellent permeation flux and interception performance. Wherein the ultrathin surface layer can obviously reduce the substance transmission resistance and greatly improve the filtering efficiency; and the compact structure forms a reliable barrier, impurities are effectively prevented from passing through, and accurate interception is ensured. Therefore, the ultrafiltration membrane can maintain the surface integrity of the membrane while ensuring the separation precision, further optimizes the permeability, and provides a new choice for the development and application of high-performance membrane materials.

A polyimide, comprising 1-100 mol % of repeating units of formula (1), based on 100 mol % of total repeating units of the polyimide, wherein each V is as defined herein; and each R1 is independently a divalent group of formula (3), wherein A is anionic, and each A is independently —O, —S, —S(O)2, —S(O)2O, —OS(O)2O, —OP(O) (OR)dO, —P(O)(Re)O, —P(O)(ORf)O, or —OP(O)(Rg)O; and X is cationic, and each X is independently Li, Na, K, Cs, Mg, Ca, Sr, Cr, Mn, Fe, Co, Ni, Cu, Ag, Zn, Cd, B, Al, Ga, In, Ge, Sn, Pb, As, Sb, phosphonium, imidazolium, guanidinium, or pyridinium; and Rd, Re, Rf, and Rg are each independently hydrogen, substituted or unsubstituted C1-8 alkyl, or substituted or unsubstituted C6-12 aryl.

The application belongs to the field of electrical insulating materials, and discloses a slot insulating material for a low-altitude aircraft motor and a preparation method thereof. The slot insulating material for the low-altitude aircraft motor comprises, from top to bottom, a first insulating paper layer, a film layer and a second insulating paper layer; the first insulating paper layer and the second insulating paper layer are each independently selected from aramid fiber paper or polyaryl sulfone fiber paper; the film layer is selected from one of polyphenylene sulfide film, polyester film, polynaphthalene ester film, polyether ether ketone film or polyetherimide film; wherein, there is no independent adhesive layer between the first insulating paper layer, the film layer and the second insulating paper layer, the first insulating paper layer and the second insulating paper layer are directly combined on the upper and lower surfaces of the film layer through hot pressing, forming a three-layer glue-free composite structure of insulating paper-insulating film-insulating paper, and fundamentally solving the engineering problem that the glue-free composite slot insulating material is prone to paper breakage.