3640 results about "Aramid" patented technology

The invention provides a low-voltage cable, and relates to the technical field of cables, the low-voltage cable comprises a conductor layer, a support layer, a shielding layer and a sheath layer, the conductor layer is composed of multiple strands of fractal stranded conductors, and each fractal stranded conductor comprises an inner-layer superfine silver-plated copper wire, a middle-layer copper-clad aluminum wire and an outer-layer nickel-plated copper alloy wire; the supporting layer wraps the conductor layer and comprises an inner supporting layer, a dynamic framework layer and an outer restraint layer, the inner supporting layer is an obliquely wound aramid fiber woven belt, the dynamic framework layer is formed by alternately arranging shape memory polymers and carbon fiber composite belts, and the outer restraint layer is a spirally wound silica gel-glass fiber composite rope. The shielding layer comprises a tinned copper wire woven mesh; the sheath layer is a thermoplastic polyurethane matrix, a microcapsule self-repairing agent is dispersed in the thermoplastic polyurethane matrix, a microcapsule comprises a siloxane prepolymer, and the thermoplastic polyurethane matrix further comprises graphene nanosheets. Through collaborative design of the fractal stranded conductor layer, the dynamic skeleton support layer, the shielding layer and the self-repairing sheath, comprehensive improvement of cable performance is realized.

The invention belongs to the technical field of gel materials, and particularly relates to aerogel powder for polyolefin modification and a preparation method and application thereof. The preparation method of the aerogel powder comprises the following steps: (1) preparing aramid nanofiber dispersion liquid; (2) preparing a polypyrrole coated aramid nanofiber dispersion liquid; (3) mixing polyamide acid and the polypyrrole coated aramid nanofiber dispersion liquid, and then carrying out partial imidization and solvent exchange to prepare hydrogel; and (4) carrying out freeze drying, thermal imidization and crushing to obtain the aerogel powder for polyolefin modification. The aerogel powder is a porous solid material formed by forming one-dimensional composite fibers from aramid nanofibers and polypyrrole and combining the one-dimensional composite fibers with polyimide resin. The aerogel powder and polyolefin resin are compounded to obtain the polyolefin resin composite material with high strength and antistatic property, and the polyolefin resin composite material can be widely applied to the fields of pipes, plates, grouting equipment parts, grouting bags and the like.

The invention belongs to the technical field of fiber materials, and particularly relates to a modified aramid nanofiber as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) preparing an aramid nanofiber dispersion liquid; (2) modifying the aramid nanofiber by using POSS; and (3) carrying out in-situ polymerization on polypyrrole on the surface of the aramid nanofiber. POSS (polyhedral oligomeric silsesquioxane) has a relatively large volume exclusion effect, the template effect of long-chain alkyl quaternary ammonium salt can be influenced by scattered adhesion of POSS on the surface of aramid nanofiber, uneven polymerization of pyrrole monomers is caused, and formation of a rough structure on the surface of the fiber is facilitated. According to the invention, the polypyrrole-coated aramid nanofiber with a coarse structure is used as a polyolefin modified material, so that the problem of low interfacial force existing in a common filler is solved, and the polyolefin resin composite material with high strength and antistatic property is obtained and can be widely applied to the fields of pipes, plates, grouting equipment parts, grouting bags and the like.

The invention relates to the field of aramid fiber band defect detection, and discloses an X-ray-based aramid fiber band defect online detection method and device. The method comprises the following steps: carrying out potential defect analysis on a physical characteristic image and a material parameter distribution diagram to obtain spatial distribution data of a potential defect region; physical characteristic quantitative analysis is carried out on the spatial distribution data of the potential defect area, a defect physical descriptor is obtained, and the defect physical descriptor comprises a density anomaly feature, a molecular chain orientation disorder degree and a thermal anomaly feature; and performing multi-dimensional feature extraction and weight distribution on the defect physical descriptor according to a preset material performance standard to obtain a quality score and a physical performance parameter of the aramid fiber band, and generating a defect detection report according to the quality score and the physical performance parameter. According to the invention, the comprehensiveness, accuracy and reliability of aramid fiber band defect detection are improved.

The invention relates to the field of friction materials, and discloses a friction material with a stable friction coefficient for an electromagnetic brake and a preparation method of the friction material. An adhesive comprises polysiloxane modified phenolic resin, benzoxazine and butyronitrile rubber powder; the reinforcing material comprises 1414 para-aramid pulp, calcium sulfate whiskers, composite mineral fibers, copper fibers and modified needle-like wollastonite; the friction increasing material comprises macroporous shell activated carbon, friction particles, garnet powder, barite and nano hafnium nitride; the antifriction material comprises graphite fluoride, nylon and composite modified hydroxyl silicate; the composite modified hydroxyl silicate is obtained by modifying hydroxyl silicate with diisocyanate and stearic acid and then compounding silane modified micro-nano calcium carbonate. The friction material provided by the invention is used for improving the braking stability of an electromagnetic brake and reducing equipment vibration.

The invention discloses a hollow aramid aerogel fiber with a hierarchical pore structure as well as a preparation method and application of the hollow aramid aerogel fiber. The preparation method comprises the following steps: by using a coaxial wet spinning method, using a spinning solution A as a shell spinning solution and a spinning solution B as a core spinning solution, simultaneously extruding the spinning solution A and the spinning solution B into a coagulating bath, carrying out in-situ dynamic sol-gel conversion, and then carrying out specific drying to obtain the hollow aramid aerogel fiber with the hierarchical pore structure, the middle of the hollow aramid fiber aerogel fiber with the hierarchical pore structure is of a hollow structure, and the fiber wall is of the hierarchical pore structure. The prepared hollow aramid fiber aerogel fiber with the hierarchical pore structure has the advantages of being large in specific surface area and high in porosity, the inner diameter, the outer diameter and the wall thickness of the fiber and the size, the morphology and the pore size distribution of pores in the fiber wall can be adjusted and controlled, the preparation method has universality, the preparation process is simple, and large-scale production is easy to achieve.

The invention relates to the technical field of hollow gel fibers, in particular to a hollow aramid aerogel fiber and a preparation method thereof. By combining wet spinning with a chemical foaming method, the inner diameter, the outer diameter and the wall thickness of the fiber and the size on a fiber wall hole are regulated and controlled, the hollow aramid aerogel fiber with the high porosity is formed, and the hollow aramid aerogel fiber has high selectivity and high flux, has the properties of flame retardance, heat insulation, high mechanical strength and the like, and is suitable for large-scale production. The use performance and the application range of the aerogel fiber in the prior art are improved and expanded.

The invention provides a high-strength, light and supercritical foaming fabric and a preparation method thereof, complete fibers used by the fabric comprise core layer fibers and a skin layer material, the outer side of the core layer fibers is uniformly coated with the skin layer material, and the skin layer material can be foamed; the core layer fiber is at least one of aramid fiber, polyarylate fiber, polyimide fiber, ultra-high molecular weight polyethylene fiber, polyester fiber and polyamide fiber; and the skin layer is made of thermoplastic elastomer resin. The preparation method comprises the following steps: uniformly coating the outer side of the core layer fiber with the skin layer material, and then carrying out supercritical foaming on the skin layer material. According to the invention, the contradictory technical requirements of the fabric for shoes on strength, light weight, comfort and the like are solved in a simple mode; the body strength of the fiber for the shoes can be kept, and the characteristics of light weight and air permeability of the foaming fabric are also achieved; the difficulty of direct foaming of the fabric / fiber for shoes is reduced, and the vamp fabric and the shoe article which are uniform in foaming, breathable, light in weight, high in strength and soft can be obtained.

The invention discloses a modified aramid fiber as well as a preparation method and application thereof. The modified aramid fiber comprises an aramid fiber and a carbon nanotube, the aramid fiber and the carbon nanotube are connected through an amido bond, the length of the carbon nanotube is 1-5 [mu] m, and the surface of the carbon nanotube is grafted with an amino-containing polymer. According to the modified aramid fiber disclosed by the invention, the surface roughness of the aramid fiber is improved due to the fact that the carbon nanotubes with the length of 1-5 microns are grafted on the surface, so that the aramid fiber and the epoxy resin generate a mechanical locking effect. Furthermore, the amino groups on the surface of the modified aramid fiber are covalently bonded with the epoxy resin, so that the bonding force between the fiber and the resin is further improved. In addition, the modulus of the introduced interface layer is between the modulus of the resin and the modulus of the aramid fiber, so that the defects at the interface of the fiber composite material under working conditions can be reduced. Meanwhile, the modified aramid fiber can be continuously produced, the treatment process is simple, efficient and green, and industrial amplification is facilitated.

The invention relates to the technical field of friction materials, and particularly discloses an electromagnetic brake friction material prepared from granules and a preparation process of the electromagnetic brake friction material in order to solve the problem that an existing electromagnetic brake friction plate is difficult to prepare or insufficient in performance. The reinforcing material comprises plasma modified aramid pulp, coupling modified composite mineral fibers, SiO2 coated tetrapod-like zinc oxide whiskers and carbon fiber-aluminum silicon whiskers; the filler comprises modified needle-like wollastonite and organic modified precipitated barium sulfate; the adhesive comprises boron-silicon synergistic modified phenolic resin and modified carboxy nitrile rubber. The raw materials are improved, and granules are prepared by adopting a mixing and crushing process, so that the content of an adhesive can be greatly reduced, meanwhile, the die filling efficiency can be improved, the die thickness and the high-temperature heat fading of the friction material can be reduced, a cold press molding process can be omitted, and the qualification rate of finished friction materials can be improved.

The invention discloses PBa reinforced aramid III nanofiber flame-retardant aerogel and a preparation method thereof, and belongs to the field of aerogel preparation. The preparation method comprises the following steps: constructing aramid fiber III nanofibers by a deprotonation method, then preparing aramid fiber III nanofiber gel by protonation, then blending a benzoxazine solution and phosphoric acid, and finally freeze-drying to obtain the flame-retardant aerogel. The prepared flame-retardant aerogel is composed of phosphoric acid catalyzed granular polybenzoxazine (PBa) and a cross-linked aramid fiber III nanofiber skeleton and has a longitudinal stripe pore structure, and the granular PBa with phosphoric acid covers aramid fiber III nanofibers to cooperatively construct a continuous and stable flame-retardant skeleton, so that a multi-stage flame-retardant structure is provided for the flame-retardant aerogel. The flame-retardant aerogel prepared by the invention has good and stable mechanical properties and excellent flame-retardant and heat-insulating capabilities, and has a wide application prospect in the field of flame retardance and heat insulation.

The invention provides an aramid fiber coated diaphragm, a preparation method thereof and an electrochemical device, and relates to the technical field of battery diaphragms.A coating of the aramid fiber coated diaphragm shows inconsistent pore diameters in the thickness direction, on one hand, dissolved transition metal ions can be blocked and adsorbed, and on the other hand, the aramid fiber coated diaphragm has high porosity; the high liquid absorption and retention capacity of the diaphragm can be guaranteed, the ionic conductivity can be improved, and then fast charging under the high-rate condition is achieved. The invention also provides a method for preparing the diaphragm, and the aperture of the section of the coating layer is differentiated by regulating and controlling the content of the cosolvent, the content of aramid in the aramid stock solution and the steam bath temperature.

The invention belongs to the technical field of personal protection equipment, and particularly relates to a lightweight cut-resistant four-dimensional structure fabric based on high-performance composite fibers and a preparation method of the lightweight cut-resistant four-dimensional structure fabric. The structure is based on a high-performance composite fiber material and a nano silicon carbide embedding technology of high-performance polyethylene fibers, the hardness bottleneck of a single material is broken through, and multi-fiber compatibility is improved through cooperation of polyurethane fiber surface activation and polyurethane fiber anti-melting modification. The gradient twist core sheath yarn is a high-performance composite yarn, and the strength and the flexibility are balanced. In the aspect of the oversleeve fabric structure, a three-dimensional protection system comprising a honeycomb structure, a silica gel liner and a skin-friendly inner layer is adopted, so that the integration of multiple functions of hydrophobicity, fusion resistance and buffering of a light-weight cut-resistant material is realized. Under the EN 388 standard, 5-level cutting prevention can be achieved, a single high-performance polyethylene fiber cutting prevention oversleeve can only reach 3-4 levels, the weight of the composite fiber material is reduced by 40% compared with that of a full aramid fiber oversleeve, the thickness is reduced by 25%, and the composite fiber material can be suitable for complex scenes such as petroleum and electric power.

The invention relates to the technical field of cables, and discloses an anti-torsional fatigue and corrosion-resistant wind power cable and a manufacturing process thereof, the anti-torsional fatigue and corrosion-resistant wind power cable comprises a three-phase cable core main body, a dynamic compensation anti-torsion layer, a multifunctional corrosion-resistant barrier layer and an outer sheath, the three-phase cable core main body comprises a stranded conductor, a filling inner layer and an insulating layer; the dynamic compensation anti-torsion layer comprises an incongruous spiral supporting layer and a shape memory alloy compensation layer, and the incongruous spiral supporting layer comprises aramid fiber bundles and a nickel-cobalt alloy wire woven mesh; the multifunctional anti-corrosion barrier layer is arranged on the outer side of the dynamic compensation anti-torsion layer and sequentially comprises an anti-corrosion barrier bottom layer, an anti-corrosion barrier middle layer and an anti-corrosion barrier bottom layer surface layer from inside to outside. Through the gradient composite structure design, the problem of failure of a traditional wind power cable under long-term dynamic load and severe environment is effectively solved, and the torsional fatigue resistance, the corrosion resistance and the environmental adaptability are remarkably improved.

The invention relates to the field of aramid fabric recycling and reusing, in particular to a method for preparing flame-retardant shielding military tent fabric by recycling waste aramid fabric, which comprises the following steps: step 1, treating the waste aramid fabric with ionic liquid; 2, opening the aramid fabric and recycling aramid fibers; step 3, preparing regenerated flame-retardant prefabricated filaments; step 4, preparing tent base cloth; and step 5, preparing the heat-insulating shielding military tent fabric. Starting from multiple dimensions of aramid fiber recycling and reusing, micro-nano flame-retardant fiber preparation, fabric structure design, functional finishing and the like, more than 98% of flame-retardant viscose and aramid fiber in the aramid fiber blended fabric are recycled and utilized at high value, and the military tent fabric finally developed has the advantages that the flame-retardant viscose and the aramid fiber in the aramid fiber blended fabric are recycled and utilized at high value; the composite material integrates multiple functions of shielding and wave absorbing (the shielding rate is 72dB, the reflectivity is 34.32 dB, and the effective bandwidth is 13.8 GHz), flame retardance, heat insulation, water resistance, oil repellency, air permeability, moisture permeability, weather resistance, softness, durability and the like, and can be used for developing military tents.

The invention discloses a sacrificial layer prepreg for a composite material and a preparation method of the sacrificial layer prepreg, and belongs to the field of composite material forming. The preparation method comprises the following steps: mixing an inorganic filler with resin, and performing film forming treatment to obtain a resin adhesive film; coating the resin adhesive film on the surface of a fiber to obtain a sacrificial layer prepreg; after the sacrificial layer prepreg is prepared, the sacrificial layer prepreg, the wave-absorbing prepreg and the structural prepreg are sequentially laid on the surface of a tool according to the tool thickening requirement, co-curing treatment and demolding treatment are carried out according to the curing process of the structural prepreg, and the composite material with the surface coated with the sacrificial layer prepreg is prepared. According to the sacrificial layer prepreg for the composite material, the aramid fiber with excellent flexibility is adopted as a carrier, direct manual stripping can be achieved, the actual laying layer number can be adjusted according to the tool thickness requirement, and compared with a traditional numerical control cutting method, the stripping efficiency is higher, and thickness control is more accurate.

The invention relates to the technical field of aromatic polyamide high polymers, in particular to a modified poly-p-phenylene terephthamide fiber with high elongation at break and a preparation method of the modified poly-p-phenylene terephthamide fiber. According to the invention, a small amount of 3, 4-difluorobenzene is introduced According to the preparation method, the third monomer containing 4, 4 '-diaminodiphenyl ether and the fourth monomer containing a diaminophenoxy functional group are added, and the molar ratio of the third monomer and the fourth monomer in the total amount of the diamine monomer is controlled, so that the rigid molecular chain structure of the conventional para-aramid fiber is destroyed to a certain extent, the breaking strength of the fiber is maintained, the elongation at break of the polymer fiber is enhanced, and the service life of the polymer fiber is prolonged. The prepared modified poly-p-phenylene terephthamide can still adopt a dry-jet wet spinning process, the cost of a new production line of a factory is saved, the fiber with stable elongation at break index is obtained by optimizing process conditions and parameters, and the elongation at break of the prepared fiber is 3.6% or above.

The invention discloses a high-strength corrosion-resistant aramid composite material and a preparation process thereof, and relates to the technical field of aramid composite materials, the high-strength corrosion-resistant aramid composite material comprises the following components by mass: 60-80 parts of ethylene propylene diene monomer, 20-40 parts of hydrogenated nitrile rubber, 10-15 parts of polytetrafluoroethylene, 18-30 parts of a filler, 10-15 parts of aramid fiber, 5-8 parts of a plasticizer, and 3-6 parts of a vulcanizing agent. The EPDM rubber, the hydrogenated nitrile rubber and the polytetrafluoroethylene are compounded, and the aramid fibers and the filler are added, so that the composite material with good mechanical property and corrosion resistance is obtained; by modifying the ethylene propylene diene monomer and the aramid fiber, the compatibility among the materials is improved, and the comprehensive performance of the composite material is further improved.

The utility model discloses a bending-resistant radio frequency coaxial cable, which comprises an inner conductor, an insulating layer, a shielding layer and a sheath layer which are sequentially arranged from inside to outside, the inner conductor is formed by concentrically twisting a plurality of strands of silver-plated copper wire monofilaments; the insulating layer comprises an inner insulating layer and a polytetrafluoroethylene film outer insulating layer; the inner insulating layer is wrapped outside the inner conductor and is formed by sintering a polytetrafluoroethylene tape; the polytetrafluoroethylene film outer insulating layer is wrapped outside the inner insulating layer; the shielding layer comprises an inner shielding layer, a middle layer and an outer shielding layer, and the inner shielding layer is a silver-plated copper strip wrapping layer and wraps the insulating layer; the middle layer is a polyimide aluminum foil composite belt wrapping the inner shielding layer; the outer shielding layer is a silver-plated aramid yarn woven layer and is woven outside the middle layer; the sheath layer is a polytetrafluoroethylene sheath layer. The cable provided by the utility model has the characteristics of high-frequency bending resistance and good environment resistance, and also has excellent electrical transmission performance.

The invention discloses a preparation method and application of polyvinyl alcohol assisted molded aramid nanofiber aerogel. The preparation method of the aerogel comprises the following steps: pulping aramid pulp, homogenizing and centrifuging to obtain an aramid nanofiber aqueous dispersion; dissolving polyvinyl alcohol in deionized water to obtain a polyvinyl alcohol aqueous solution; and mixing the aramid nanofiber aqueous dispersion and the polyvinyl alcohol aqueous solution, placing the mixture in a container, and carrying out liquid nitrogen unidirectional freezing, freeze drying and low-temperature heat treatment to obtain the aerogel. According to the aerogel prepared by the method, due to the physical winding effect of a polyvinyl alcohol polymer chain and the chemical combination effect of a hydrogen bond, dispersion of the aramid nanofiber in a water-based solvent is synergistically promoted; therefore, the phenomena of agglomeration and adhesion, non-uniform forming, slag and powder falling and the like caused by Van der Waals interaction, hydrophilic and hydrophobic interaction and the like among the adjacent aramid nanofibers in the freezing casting process are avoided; the aramid nanofiber in the aerogel subjected to low-temperature heat treatment is close to single distribution, and a viscous polyvinyl alcohol molecular chain is converted into a conjugated carbon chain, so that the mechanical properties of compression, stretching and the like of the aerogel are remarkably improved. In addition, the aerogel can be used as a wave-absorbing material after being carbonized at a high temperature, has the advantages of thin thickness and light weight, and has the wave-absorbing capability of wide frequency band and strong absorption.

The invention relates to the technical field of polymer composite materials, in particular to an aramid nanofiber low-frequency wave-absorbing composite material and a preparation method thereof. The aramid nanofiber low-frequency wave-absorbing composite material is prepared from the following raw materials: magnetic wave-absorbing fibers and aromatic polyamide nanofibers, the magnetic wave-absorbing fiber is prepared from a raw material system comprising FeCo magnetic wave-absorbing filler, aromatic polyamide fiber and a hyperbranched polysiloxane modifier. The aramid nanofiber low-frequency wave-absorbing composite material prepared by taking the magnetic wave-absorbing fibers and the aromatic polyamide nanofibers as raw materials not only has excellent mechanical properties (the tensile strength can reach 133 Mpa), but also has excellent wave-absorbing performance (the minimum reflection loss can reach-46.8 dB, and the low-frequency effective absorption bandwidth (EAB) is 2.24 GHz (5.52 GHz to 7.76 GHz). The method can be widely applied to the fields of communication and electronic equipment.

The invention provides a composite current collector, a secondary battery and an electronic device, the composite current collector comprises a base film and a conductive layer arranged on at least one surface of the base film, the base film comprises at least one of a polypropylene film, a polyethylene film, a polyimide film or aramid fiber, the porosity of the base film is P1%, 30 < = P1 < = 80, the aperture of the base film is phi1nm, 200 < = phi1 < = 1000, and the thickness of the conductive layer is 0.1-0.5 mm. The porosity of the conductive layer is P2%, 10 < = P2 < = 75, the aperture of the conductive layer is phi 2nm, and 100 < = phi 2 < = 800. The composite current collector comprises the structure, the type, the porosity and the aperture of the base membrane and the porosity and the aperture of the conductive layer are within the range of the application, so that lithium ions can be bidirectionally transmitted, the transmission path of the lithium ions is shortened, and the rate capability of the secondary battery is favorably improved.

The invention discloses nano ettringite particle reinforced aramid nanofiber aerogel as well as a preparation method and application thereof, and belongs to the technical field of aerogel. The preparation method provided by the invention comprises the following steps: dissolving a calcium source, an aluminum source and sulfate in water, adding a first surfactant, adjusting the pH value to 9-12, stirring for reaction, and after the reaction is finished, washing a solid product to be neutral to obtain nano ettringite particles; uniformly stirring and mixing the nano ettringite particles, para-aramid nanofibers, a second surfactant and a cross-linking agent in water to obtain an ettringite / aramid nanofiber dispersion liquid; the ettringite / aramid nanofiber dispersion liquid is sequentially subjected to concentration, directional freezing and freeze drying, and the ettringite / aramid nanofiber composite material is obtained. The preparation method disclosed by the invention is simple, the raw materials are easy to obtain, and the obtained nano ettringite particle reinforced aramid nanofiber aerogel has relatively high mechanical strength and thermal stability.

The invention discloses an aramid fiber coated polyolefin battery diaphragm and a preparation method and application thereof, the aramid fiber coated polyolefin battery diaphragm can be used for manufacturing a lithium ion battery, and the aramid fiber coated polyolefin battery diaphragm is prepared by the following method: (1) treating a polyolefin base membrane by using a strong oxidant to obtain a modified base membrane; (2) dissolving aramid resin in a solvent to obtain an aramid coating solution; and (3) coating the surface of the modified base membrane with the aramid fiber coating liquid, and then curing. According to the invention, the interface bonding strength of the base membrane and the aramid fiber coating is obviously enhanced, so that the aramid fiber coating can give full play to high heat resistance, on the basis of ensuring the tensile strength of the diaphragm, the overall thermal shrinkage rate of the diaphragm is reduced, the risk of high-temperature short circuit is effectively inhibited, and the composite diaphragm with high porosity, strong mechanical property, high uniformity and no surface defect is formed; the method is suitable for high-energy-density lithium ion batteries, and the safety and high-temperature working condition stability of the batteries are remarkably improved.

The invention relates to the technical crossing field of polyphenylene sulfide fiber paper, special papermaking and insulation paper, in particular to high-temperature-resistant polyphenylene sulfide fiber composite insulation paper and a preparation process thereof. The high-temperature-resistant polyphenylene sulfide fiber composite insulation paper with a dense structure similar to reinforcing steel bar-mortar is prepared by preferably selecting the polyphenylene sulfide fiber with higher cost performance as a raw material and taking the aramid fibrid as a filling agent and an adhesive and adopting a wet papermaking process. The prepared composite paper has excellent temperature resistance and chemical corrosion resistance, the production process flow is short, the production process is free of pollution, the industrial production cost of the composite paper can be reduced, the temperature resistance and chemical stability of medium-and-low-end application insulation paper are improved, the application field of the composite paper in a more severe environment is widened, and the composite paper has good application prospects. Good economic benefits and application values are realized.

The invention relates to the technical field of medical supplies, and discloses an anti-puncture medical packaging film and a preparation method thereof. Comprising the following raw materials in parts by weight: an ethylene copolymer, modified aramid fibers, a reinforcing agent, an auxiliary agent, an antioxidant and an antistatic agent. The preparation method of the anti-puncture medical packaging film comprises the following steps: raw material blending, tape casting, film blank drying, stretching and shaping, and rolling. According to the technology, the modified aramid fibers are fully dispersed in the packaging film with the ethylene copolymer as the matrix, so that the puncture resistance of the packaging film is greatly improved, sharp objects are effectively prevented from penetrating through the packaging film, medical products are better protected, the damage risk of the products in the transportation and storage process is reduced, meanwhile, through modification, the service life of the packaging film is prolonged, and the service life of the packaging film is prolonged. The antibacterial performance is improved, and the medical material is more suitable for protection application of medical equipment.

The invention discloses a preparation method and application of an MXene / aramid nanofiber electromagnetic shielding hydrogel. The preparation method comprises the following steps: preparing an MXene / aramid nanofiber electromagnetic shielding hydrogel; the preparation method comprises the following steps: step 1, ultrasonically mixing a Ti < 3 > C < 2 > T < x > MXene dispersion liquid with liquid metal to obtain an MXene-coated LM mixed solution; step 2, adding an aramid nanofiber dispersion liquid prepared by deprotonation and a PVA (Polyvinyl Alcohol) solution into the MXene-coated LM mixed solution, and stirring to obtain a uniform solution; and 3, pouring the uniform solution into a mold, freezing, unfreezing, and demolding to obtain PVA-ANF / MXene-coated LM hydrogel, namely the MXene / aramid nanofiber electromagnetic shielding hydrogel. After the base material is prepared into the hydrogel, internal multiple reflection is structurally enhanced, and secondary pollution caused by reflection of electromagnetic waves is reduced.

The present invention pertains to a long-fine aramid single fiber having a maximum fiber diameter of less than 2,000 nm and a minimum fiber length of greater than 10 μm, wherein the degree x of crystallinity determined by the expression x=(1-∆Qx / ∆Q0)×100 (%) (in the expression, ∆Qx is a heat capacity change amount before and after the glass transition point of the long-fine aramid single fiber, and ∆Q0 is a heat capacity change amount before and after the glass transition point of an amorphous aramid) is at least 60%. The present invention can provide an aramid single fiber which is very thin and long and has a high degree of crystallinity.

The invention relates to the technical field of knitted fabrics, in particular to a high-strength wear-resistant anti-snagging functional dry knitted fabric for exercise training and a production process thereof, and the production process comprises the following steps: weighing the following raw materials in parts by weight: 30-40 parts of polyester fibers, 20-30 parts of aramid fibers, 5-10 parts of jade fibers and 5-10 parts of polyamide fibers; polyester fibers, aramid fibers, jade fibers and polyamide fibers are subjected to relaxation treatment and then subjected to a drawing procedure, and the mixed roving is obtained. According to the knitted fabric for exercise training, polyester fibers, aramid fibers, jade fibers and polyamide fibers are blended and blended to prepare mixed roving, meanwhile, the mixed roving is infiltrated and improved through infiltrating liquid, finally, the mixed roving is matched with modified polyester filaments to be subjected to circular knitting improvement, and the obtained knitted fabric has the advantages of being excellent in wear resistance, mechanical strength performance and snagging performance, good in elasticity and good in elasticity. And the knitted fabric has remarkable moisture absorption, dryness and dryness and washing resistance, and the comprehensive coordination of the product is excellent.

The invention belongs to the technical field of cable manufacturing, and discloses a large-section cable for vehicle end bridging, which sequentially comprises a conductor layer, an insulating layer, a shielding layer and a sheath layer from inside to outside, the shielding layer comprises a forward winding type braided shielding wire and a reverse winding type meta-position aramid fiber, the braided shielding wire is formed by twisting a plurality of strands of metal alloy, and the sheath layer is arranged between the conductor layer and the insulating layer. The meta-position aramid fiber adopts stranded meta-position aramid fiber filaments as reverse winding weaving filaments, the sheath layer adopts high-temperature hot drying tunnel vulcanization extrusion type silicone rubber, the temperature of a high-temperature section of a drying tunnel is not lower than 400 DEG C, the vulcanization time is not less than 1 minute, and the meta-position aramid fiber is embrittled and cracked until carbonization failure due to the high temperature of the high-temperature section of the drying tunnel. The cable is suitable for production of a winding shielding layer of a large-section cable for vehicle end bridging with silicone rubber as an insulating layer and a sheath layer, and through introduction of reverse winding meta-position aramid fibers, on the basis of not influencing the use of the whole product, the product structure is further stabilized, and the use stability and safety of the product are ensured.