391 results about "Polymeric membrane" patented technology

The invention relates to the technical field of polymeric membrane materials, and particularly discloses an antistatic polyethylene composite membrane and a preparation method thereof. Comprising the following raw materials in parts by weight: 100 parts of low-density polyethylene, 5-9 parts of high-density polyethylene, 10-20 parts of maleic anhydride grafted polyethylene, 8-15 parts of a polyvinyl alcohol modified material, 3-5 parts of antistatic modified carbon black, 0.5-1 part of an antioxidant and 1-2 parts of a dispersing agent, the polyethylene composite film has excellent dispersibility, can effectively enhance the mechanical properties of the polyethylene composite film through the synergistic effect of physical filling and chemical grafting, forms a layer of conductive network structure, namely a conductive film, on the surface of the material through the combined effect of the polyethylene composite film and the antistatic agent, prevents the generation and accumulation of static electricity, and has good compatibility among the raw materials. And the material has excellent mechanical property and antistatic property.

The invention belongs to the technical field of polymeric membrane materials, and particularly discloses a polycarbonate / cellulose acetate blended ultrafiltration membrane as well as a preparation method and application thereof. The polycarbonate / cellulose acetate blended ultrafiltration membrane is prepared by blending cellulose acetate and polycarbonate, and has the advantages of simple preparation method, low cost, low energy consumption, good stability and the like; meanwhile, the double advantages of polycarbonate and cellulose acetate are combined, remarkable hydrophilic enhancement and efficient permeability are shown, the purpose of separation and purification can be achieved, and the composite material has huge potential application prospects in the fields of seawater desalination, sewage treatment, rainwater collection and treatment and the like.

The invention belongs to the field of polymeric membranes. The invention relates to a BOPLA (biaxially-oriented polylactic acid) film with high stretching ratio and a preparation method thereof. The packaging film comprises the following raw materials in parts by weight: 80-90 parts of PLA; 10 to 20 parts of PPC-P (Polypropylene Chloride-P); 10-15 parts of a plasticizer; 3.0 to 5.0 parts of a chain extender; 0.3 to 0.5 part of an antioxidant; 0.5 to 1.0 part of a lubricant; 0.1 to 0.3 part of an anti-hydrolysis agent; wherein the total mass of the PLA and the PPC-P is 100 parts; the preparation method comprises the following steps: mixing, extruding and plasticizing the raw materials according to the formula, and carrying out an asynchronous two-way stretching process, heat setting, traction, slitting and rolling. According to the present invention, the defects of mechanical property degradation and poor optical property of the PLA under the high stretching rate in the prior art can be effectively solved, and the great application potential is provided.

The invention relates to the technical field of building waterproof materials, and provides a multi-layer self-protection self-adhesion waterproof roll and a preparation method thereof. The multi-layer self-protection self-adhesion waterproof roll sequentially comprises an isolating membrane, a self-adhesion glue layer, an elastic polyester felt buffer layer, an adhesive layer and a polymeric membrane layer from top to bottom, and the self-adhesion glue layer is prepared from, by weight, 65-75 parts of butyl rubber, 15-20 parts of SBS modifier, 8-12 parts of tackifying resin I, 0.5-1.5 parts of anti-aging agent, 8-15 parts of filler, 1-3 parts of polyethylene and 1-2 parts of flexibilizer. The tackifying resin I comprises rosin resin. According to the technical scheme, the problems that the self-adhesive waterproof roll does not have the self-protection capability, the peel strength is low and the holding power is poor in the prior art are solved.

The invention discloses an amphiphilic chitosan and plant nanocellulose composite coating fresh-keeping material, which is prepared from the following ingredients in percentage by mass: 0.5 to 20 percent of amphiphilic chitosan, 0.1 to 5.0 percent of plant nanocellulose, 0.5 to 10.0 percent of coalescing agents, 0.1 to 3.0 percent of antioxidants and the balance deionized water. Wherein the amphiphilic chitosan is prepared from chitosan, quaternary phosphonium salt and sorbic acid. Amphipathic chitosan of the material has hydrophilic groups such as amino and carboxyl and a sorbate hydrophobic group, has hydrophilicity and hydrophobicity at the same time, and is extremely easy to combine with substances such as a coalescing agent, plant nanocellulose and an antioxidant to form a stable polymeric membrane layer, so that the mechanical property after membrane formation is remarkably improved, and the material has a good application prospect. Meanwhile, the plant nanocellulose particles can be stably coated in the polymeric membrane material layer, so that the mechanical property of the material is enhanced, and lasting and efficient antibacterial and antioxidant effects are realized. The invention further discloses a preparation method and application of the amphiphilic chitosan and plant nanocellulose composite coating fresh-keeping material.

The invention discloses a bipolar current collector and a preparation method thereof, a bipolar electrode and a battery, the bipolar current collector comprises a base film layer, an aluminum layer is arranged on the surface of one side of the base film layer, and a copper layer is arranged on the surface of the other side of the base film layer; the base film layer comprises a middle polymeric film layer and ceramic layers on the surfaces of the two sides of the polymeric film layer; miniature channels for lithium ions to pass through are distributed on the bipolar current collector along the thickness direction, and the miniature channels penetrate through the aluminum layer, the base film layer and the copper layer. A diaphragm in a traditional bipolar electrode is omitted, so that the volume energy density in the battery is remarkably improved, lithium ions in the battery can have diffusion channels in multiple directions, the internal resistance of the battery is reduced, and the rate capability is improved. According to the invention, a diaphragm lamination process is omitted, the production efficiency can be improved, and meanwhile, the risk of short circuit at the edges of the positive and negative active material layers caused by alignment errors of the lamination process is avoided.

The invention relates to the technical field of protective films, and particularly discloses a composite glass protective paste for a flexible folding screen and a preparation method of the composite glass protective paste. The composite glass protection paste for the flexible folding screen sequentially comprises a functional base film, a first thermosetting polymer film, a UTG ultrathin glass layer, a second thermosetting polymer film and an OCA adhesive layer from top to bottom, the preparation method of the OCA adhesive layer comprises the following steps: carrying out activating treatment on nano silicon dioxide particles to obtain modified particles with cations on the surfaces; carrying out reaction on the modified particles and molten hydroxy acrylic resin under the ultrasonic action, and carrying out extrusion granulation to obtain elastic acrylic master batches; uniformly mixing the elastic acrylic master batch with a cross-linking agent and a photoinitiator to obtain the acrylic OCA; and coating OCA on one surface of the release film, and performing ultraviolet curing to obtain an OCA layer. According to the composite glass protection paste for the flexible folding screen, the bending resistance of the protection paste is improved.

The invention relates to an antistatic plastic film and a preparation method thereof, and belongs to the technical field of polymeric membrane materials, the antistatic plastic film is composed of a PET base film and an antistatic coating formed by curing an antistatic coating, the antistatic coating comprises the following components in parts by weight: 100 parts of organic silicon resin, 12-18 parts of an antistatic agent, 0.8-1.1 parts of a dispersing agent, 0.4-0.6 part of a bridging agent, 0.15-0.2 part of a flatting agent and 55-60 parts of a solvent, according to the antistatic agent, lamellar graphene is used as an electrostatic charge release matrix, a silane coupling agent KH-550 is used for introducing amino to the surface of a lamellar layer for modification, methyl chloroacetate and the amino grafted to the lamellar layer are used for substitution, finally, methyl iodide and a substituted amine compound are subjected to quaternization reaction, quaternary ammonium cations are introduced to the surface of the graphene lamellar layer, and the antistatic agent is obtained. And a continuous current collecting layer is formed in the coating, so that the generated electrostatic charge is timely led out, and the film material is endowed with excellent antistatic property.

The invention relates to the technical field of waterproof coiled materials, and provides a tensile double-lap-joint polymeric membrane base waterproof coiled material which sequentially comprises a first isolating membrane, a first permeable reaction adhesive layer, a first polymeric membrane base layer, a second permeable reaction adhesive layer, a second polymeric membrane base layer, a third permeable reaction adhesive layer and a surface layer from bottom to top, the surface layer is formed by connecting a second isolating membrane and an anti-sticking layer; a first lapping opening and a second lapping opening are formed in the two sides of the second permeable reaction adhesive layer respectively, the second isolating membrane and the first lapping opening are located on the two sides of the anti-sticking layer respectively, a third isolating membrane and a fourth isolating membrane are arranged on the inner wall of the first lapping opening, and a fifth isolating membrane and a sixth isolating membrane are arranged on the inner wall of the second lapping opening. Through the technical scheme, the problems of low peeling strength and poor adhesiveness of the overlapping edge of the waterproof roll in the related technology are further improved and solved.

The invention provides a method for preparing a degradable bone-guided regeneration membrane with an asymmetric membrane layer, which comprises the following steps of: cutting a magnesium metal sheet into a magnesium net or a magnesium bracket with small holes by laser, carrying out heat treatment on the magnesium net or the magnesium bracket by using HF (Hydrogen Fluoride) to obtain a layer of MgF4 coating on the surface, and immersing the magnesium net or the magnesium bracket into a macromolecular solution until a solvent of the macromolecular coating is completely volatilized; then preparing an electrostatic spinning membrane on the surface of the sample: preparing a dense polymer membrane layer containing an antibacterial drug on the surface of the sample close to one side of the fiber tissue by adopting a hot pressing method, or preparing a dense electrostatic spinning ordered fiber membrane which contains an antibacterial nano-drug and is arranged in parallel by adopting an electrostatic spinning method; the designed structure and the used materials can realize an antibacterial function and shield fiber tissues from growing in. The nanofiber membrane which contains osteogenesis promoting substances such as nano-hydroxyapatite or nano-strontium and is conveyed disorderly is prepared on the side close to the bone tissue by adopting an electrostatic spinning technology, and the designed structure and the contained substances can promote osteogenesis.

The invention discloses a method for preparing low-grafted glucosyl stevioside at high temperature and high pressure, which comprises the following steps: taking stevioside as a receptor, beta-cyclodextrin as a donor and CGT enzyme as a catalyst for reaction to obtain reaction liquid containing glucosyl stevioside; putting the reaction liquid containing the glucosyl stevioside into a high-pressure reaction kettle, and adding a catalyst to carry out high-temperature and high-pressure cracking reaction; after the high-temperature and high-pressure cracking reaction is finished, cooling a cracking solution to room temperature, filtering, concentrating for multiple times by adopting a polymeric membrane, and collecting a trapped fluid; and carrying out spray drying on the trapped fluid to obtain the low-grafting glucosyl stevioside. According to the method, firstly, glucosyl stevioside is prepared by adopting an enzyme modification method, then splitting decomposition is performed under certain conditions, and then a specific purification process is performed, so that the prepared product is high in stability, the proportion of low-grafted glucosyl stevioside in the product is high, and the product tastes good.

The invention discloses a multi-layer polymeric membrane functional current collector and a preparation method thereof, a pole piece and a battery, and the preparation process comprises the following steps: S1, blending and granulating ultra-high molecular weight polyethylene and high density polyethylene to prepare a composite layer raw material; s2, adding the composite layer raw material and the middle layer nylon raw material into a screw extruder, and carrying out co-extrusion casting to form a composite layer-middle layer-composite layer three-layer structure film; s3, carrying out plasma activation treatment on the obtained three-layer structure film; s4, forming nanoscale pits in the outer surface of the three-layer structure film by dipping the three-layer structure film in the treating fluid; and S5, preparing a metal layer on the outer side of the three-layer structure film to obtain the multi-layer polymer film functional current collector. Through material blending optimization, multi-layer structure design and surface functionalization treatment, the mechanical property and dimensional stability of the current collector base film and the binding force between the current collector base film and a metal coating are remarkably improved.

The invention discloses a high-performance Mg < 2 + > / Li < + > separation nanofiltration membrane and a preparation method thereof, the Mg < 2 + > / Li < + > separation nanofiltration membrane is a polymer composite membrane, and is composed of a surface separation layer and a support layer; the surface separation layer is formed by self-assembling a polycation electrolyte and a polyanion electrolyte layer by layer, the supporting layer is formed by ultraviolet grafting of any one or two of sodium polystyrene sulfonate, polymethylacrylic acid 3-sulfonic acid propyl ester potassium salt and polyacrylic acid on the surface of a hydrophobic polymeric membrane, and the surface of the supporting layer is negatively charged. The negative charge amount of the supporting layer is gradually reduced from top to bottom; the whole separation membrane has the characteristics that the upper layer is hydrophilic and the lower layer is hydrophobic. By adjusting the charge density and aperture of the supporting layer, the structure of the surface separation layer is influenced, the charge repulsion effect, aperture screening effect and built-in electric field intensity of the whole membrane are enhanced, and the Mg < 2 + > / Li < + > separation factor is increased. Permeation and rapid transportation of water are promoted by virtue of a hydrophilic upper-layer and hydrophobic lower-layer structure, and the membrane flux is improved; the preparation process is simple, and the used solvent is water, so that the method is green and environment-friendly and has a good application prospect.

The present invention discloses a method for batch preparation of graphene electron microscope grids. The present invention realizes high-quality batch transfer of graphene and electron microscope grids by designing a multi-level transfer medium (including a PDMS porous template, a polymer support layer and a small molecule buffer layer) in combination with a solvent volatilization-induced elastic capillary bonding process. Specifically, the surface of the graphene is uniformly coated with a small molecule / polymer transfer medium layer, and then bonded to the PDMS porous array template. After the graphene is peeled off from the growth substrate, the graphene supported by the polymer film in the suspended part of the PDMS is bonded to the electron microscope grid using a solvent thermal bonding method; finally, the transfer medium is removed to obtain the graphene grid. The method of the present invention has the advantages of simple process, reusable PDMS template and good compatibility, and is suitable for large-scale production. At the same time, the prepared graphene grid has high cleanliness and integrity, and can meet the application requirements in the field of cryo-electron microscope grids.

The invention relates to the technical field of waterproof coiled materials, and provides an anti-aging film for a waterproof coiled material and a preparation method thereof.The anti-aging film is formed by crossing and compounding multiple layers of films, and the multiple layers of films sequentially comprise an inner layer film, a middle layer film and an outer layer film from top to bottom; wherein the outer-layer film comprises the following components in parts by weight: 80-90 parts of high-density polyethylene, 6-8 parts of black masterbatch, 10-15 parts of hydroxyl nicotinic acid compound modified carbon black, 1-2 parts of an antioxidant and 2-4 parts of a plasticizer, the modified carbon black is hydroxyl nicotinic acid compound modified carbon black, and the inner-layer film and the middle-layer film are polymer film layers. According to the technical scheme, the problem that in the prior art, the aging resistance of the film for the waterproof roll is poor is solved.

The invention discloses a high-durability waterborne polyurethane fluoride-free waterproof finishing agent as well as a preparation method and application thereof. The preparation method comprises the following steps: adding dihydroxyl-terminated silicone oil into a reactor, and carrying out high-temperature vacuumizing dehydration treatment; when the temperature of the reactor is reduced to a proper temperature, adding isophorone diisocyanate for reaction to obtain a polyurethane prepolymer; adding glycerin monostearate into the reactor for chain extension; adding a proper amount of hydrophilic chain extender into the reactor for chain extension; and adjusting the pH value, and adding water at room temperature to emulsify uniformly to obtain the high-durability waterborne polyurethane fluoride-free waterproof finishing agent. After the textile waterproof agent is applied to a textile, a layer of high-strength, flexible and wear-resistant polymeric membrane can be formed on the surface of the textile, the waterproof performance of the textile is effectively improved, meanwhile, the textile waterproof agent has good air permeability and flexibility, and the hand feeling of the textile is effectively improved. And the waterproof contact angle after multiple times of washing is slightly different from that before washing, the durability is good, and the service life is long.

Polymeric porous membranes, filter containing, and methods of making the polymeric membranes the same are disclosed. The polymeric porous membrane has a first major membrane surface and a second major membrane surface opposite of the first major membrane surface, and a first layer proximate the first major membrane surface, the first layer including a first plurality of pores having a first average pore size. The membrane includes a second layer comprising a second plurality of pores having a second pore size. In some cases, the membrane includes a third layer comprising a third plurality of pores having a third pore size.

The invention relates to the field of membrane material preparation, in particular to an amino acid derivative polymer membrane material and a preparation method thereof. The preparation method provided by the invention comprises the following steps: S1, preparing a polymer solution; S2, forming and depositing a membrane; S3, carrying out surface modification on the membrane; and S4, carrying out crosslinking treatment. The functional polymer membrane material is synthesized through the amino acid derivative, selective separation of specific ions or molecules can be achieved, and good biocompatibility, stability and application prospects are achieved. The technology can be widely applied to multiple fields of biological separation, environment purification, drug delivery and the like, and has remarkable innovativeness and practical value.

The present disclosure relates to the technical field of film material, and particularly to a polymeric polyphenol-modified polymer film, a preparation method thereof and a metallized polymer film. According to the present disclosure, corona treatment is performed to a surface of a polymer layer, so that a polar modifying liquid can uniformly coat the surface of the polymer layer, thereby forming a modification layer tightly combined with the polymer layer. Thus, the low-polarity polymer layer surface can be imparted with a durable high polarity. Consequently, the polymer layer is capable of being stably and tightly bonded to a material layer with high polarity and high surface tension, such as a metal layer, for a long period of time, effectively broadening the application scenarios for non-polar polymer substrate layers. By controlling the concentrations of the polyphenolic compound and the cross-linking agent in the modifying liquid, the modification layer formed by a cross-linking reaction can have a suitable cross-linking density and an adequate number of hydroxyl groups, thereby further effectively and stably enhancing the long-term polarity and surface tension of the polymer layer. The preparation method is simple and easy to operate, cost-effective, efficient, and easy to scale up.

The invention discloses preparation and application of light-weight and low-cost humanoid robot skin, and belongs to the field of application of humanoid robot surface materials. Comprising the following steps that S1, waterborne polyurethane slurry is sprayed to an inner mold body of a mold A and an inner mold body of a mold B correspondingly, and drying is conducted; foaming type polyurethane resin is injected into the mold A, demolding is conducted after the foaming type polyurethane resin is completely foamed and cured at the normal temperature, and a polyurethane foaming body is obtained; s2, a platinum silica gel catalyst is sprayed on the polyurethane foaming body and the mold B; s3, a polyurethane foaming body is fixed into the mold B; injecting the mixed silica gel into a gap of the mold B; curing and demolding; and S4, after demolding, carrying out surface hand feeling treatment by using skin feeling water-based slurry, and drying to obtain the light-weight and low-cost humanoid robot skin. The polyurethane forms a compact polymeric membrane after being dried, so that the problem of oil leakage on the surface of the silica gel is effectively solved, and the surface wear resistance, scratch resistance and light aging resistance are remarkably improved.

The present invention relates to a medical device manufactured using the additive manufacturing process (3D printing). It is a medical device used preferably as a bone graft composed of a porous structure based on bioceramics based on β-tricalcium phosphate (β-TCP) or hydroxyapatite, which may or not contain nanostructures in its composition, for example: carbon nanostructures (graphene, graphene oxide, reduced graphene oxide, carbon nanotubes, etc.) and, in preferred embodiments, stem cells and polymeric membrane. Also, the present invention relates to the use of this device as a bone graft and the process of preparing this device.

The invention discloses a porous catalytic membrane, a membrane electrode assembly and a water electrolysis device, and relates to the technical field of new energy. The porous catalytic membrane provided by the invention comprises a porous polymeric membrane formed by interweaving randomly arranged nanofibers, and a catalyst covering the surfaces of the nanofibers, the porous polymeric membrane has a self-supporting structure and a large specific surface area, and provides a large number of loading sites for the catalyst; the catalyst can be directly anchored on the nanofiber of the porous polymeric membrane through a physical or chemical preparation method, uniform dispersion is realized, and no ionomer is needed for coating, so that the problems of high cost and performance reduction caused by use of the ionomer are avoided, the exposure degree of catalytic active sites is remarkably improved, and the catalytic activity of the catalyst is improved. Therefore, the utilization efficiency of the catalyst is improved and the dosage of the noble metal catalyst can be reduced; in addition, the porous catalytic membrane and the ion exchange membrane have excellent interface contact characteristics, and integrated combination of the porous catalytic membrane and the ion exchange membrane is facilitated.

The invention relates to the technical field of polymeric membrane materials, in particular to a functional packaging membrane material and a preparation method thereof. The packaging film material is prepared from PET, PLA, a modifier and an ultraviolet absorbent, wherein the modifier is formed by grafting dimethyl terephthalate, ethylene glycol and dihydroxyl-terminated polylactic acid to the surface of carboxylated graphene after ester exchange. Under the synergistic effect of the carboxylated graphene nanosheets and the modifier, the uniform dispersion and interface bonding strength of the nanofiller are effectively improved, so that the compatibility of PET (Polyethylene Terephthalate) and PLA (Polylactic Acid) is optimized. According to the structural design, the comprehensive performance such as tensile strength, toughness, gas barrier property and thermal deformation temperature of the composite material can be remarkably improved, and meanwhile, good processability and degradability of the material are guaranteed. The invention provides reliable technical support for developing a novel green packaging film material with high performance and low environmental burden, and has wide industrial application prospect.

The present invention refers to processes for the preparation of polymeric membranes, which can be nanostructured hybrids, containing ionic liquids and their derivatives for sequestration of CO2 from natural gas by gaseous permeation, and its referred membranes. The membranes of the present invention can be dense flat membranes, or composite asymmetric flat membranes. The invention can be applied in oil and gas extraction and renewable energies, for example, in existing gas treatment plants on off-shore platforms, replacing existing conventional polymeric membranes, as well as in new gas treatment plant designs that use polymeric membranes as natural gas purification technology, or treatment of exhausted gas streams.

This fine water discharge device is provided with: a fine water discharge element which has a base material and a conductive polymer film provided on the base material, and which changes between a moisture-absorbing state in which moisture in air is absorbed to the conductive polymer film and a moisture-releasing state in which moisture in the air is released from the conductive polymer film; in the moisture liberation state, the moisture adsorbed on the conductive polymer film is discharged as fine water with the particle size being less than 50 nanometers; a supply unit for supplying energy to the fine water discharge element; and a control unit that executes moisture absorption control for controlling the supply unit so as to supply first energy for bringing the fine water discharge element into a moisture absorption state, and moisture release control for releasing moisture from the fine water discharge element. In the moisture release control, the supply unit is controlled so as to supply second energy that causes the temperature of the fine water discharge element to be higher than the temperature in the moisture absorption state and causes the fine water discharge element to be in a moisture release state.

The invention relates to the technical field of composite structure protection stickers, and particularly discloses a composite layered protection sticker for a folding screen and a production process of the composite layered protection sticker. The invention discloses a composite layered protection paste for a folding screen. The composite layered protection paste sequentially comprises a polymeric membrane layer, ultra-thin flexible glass, a polymeric membrane layer and a functional coating from bottom to top, the polymeric membrane layer is prepared from the following components in parts by mass: 40 to 50 parts of alicyclic epoxy resin, 20 to 30 parts of hydroxyl-terminated polyisobutene, 5 to 10 parts of hydroxyl-terminated polybutadiene, 8 to 10 parts of modified vinyl alkoxy silane, 5 to 7 parts of modified nano silicon dioxide, 30 to 40 parts of curing agent, 0.4 to 0.6 part of catalyst and 30 to 50 parts of solvent; the composite layered protective paste prepared by the invention has excellent advantages in bending resistance and impact resistance.

The invention provides a polymer composition, a polymer film material, a holographic grating, a preparation method of the holographic grating, an optical film material and display equipment. The polymer composition comprises a first polymerizable monomer, a second polymerizable monomer and a film-forming resin. The first polymerizable monomer is a non-liquid crystal monomer; the second polymerizable monomer is a liquid crystal monomer, the second polymerizable monomer comprises an active group, and the second polymerizable monomer can be subjected to a copolymerization reaction with the first polymerizable monomer through the active group under illumination. The refractive index modulation degree of the optical film material can be improved by using the polymer composition.

The invention discloses a wear-resistant and fibrillating-resistant spun silk fiber and a preparation process and application thereof, a layer of smooth and continuous amino acid-containing polymeric membrane protective layer with uniform thickness is formed on the surface of the spun silk fiber, the thickness of the polymeric membrane protective layer is 50-500nm, and the thickness of the polymeric membrane protective layer is 50-500nm. The polymeric membrane protective layer enables the spun silk fibers to be wear-resistant and anti-fibrillating, the spun silk fibers are not easy to damage after being treated by dyeing and after-finishing processes, and the prepared fabric can still keep good hand feeling and color after being washed for multiple times. Besides, the preparation process is simple, efficient and wide in applicability, and the prepared wear-resistant and fibrillating-resistant spun silk fiber can be used for spinning and weaving independently or together with other fibers and can be applied to the fields of clothes, underwear, home textiles, filling and the like.

The knitted covered stent comprises a supporting layer and a flow choking layer, the supporting layer is formed by knitting knitting units and is of a hollow cylinder knitting structure, the flow choking layer is formed by knitting knitting units, the supporting layer serves as a basic framework of the stent and provides necessary mechanical support, and the flow choking layer is of a knitting structure covering the supporting layer. Wherein the flow blocking layer adopts a knitting technology, knitting units are made to be looped in a penetrating and sleeving mode and continuously knitted into a net to cover the supporting layer, the inner side of the flow blocking layer is attached to the outer side of the supporting layer, the knitted covered stent of the knitted structure and the knitted structure is obtained, an interlayer connecting structure exists between the supporting layer and the flow blocking layer, and interlayer connecting and fixing of the supporting layer and the flow blocking layer are achieved; compared with a traditional design of cutting a skeleton and a polymeric membrane, the stent shows more excellent adherence and compliance, and can better adapt to the form and change of a blood vessel, so that the implantation effect and the treatment effect of the stent are improved.

The invention discloses a durable PVDF (Polyvinylidene Fluoride) polymeric membrane and a preparation method thereof, and relates to the technical field of polymeric membranes, the preparation method comprises the following steps: preparing a PVDF base solution, injecting a dynamic disulfide cross-linking agent, preparing a porous membrane material by electrostatic spinning, freeze-drying treatment, thermal cross-linking curing treatment and surface modification; the preparation method comprises the following steps: dissolving PVDF resin in a GVL organic solvent to form a mixed solution, injecting a dynamic disulfide cross-linking agent into the mixed solution, and adding the nano composite material. By introducing the dynamic disulfide cross-linking agent, the self-repairing function of the PVDF film is realized, the problem that the mechanical property is reduced and fails due to microcrack accumulation of the traditional PVDF film is solved, the mechanical property of the PVDF film is remarkably improved, and the service life of the film is prolonged.