5289 results about "Polyacrylonitrile" patented technology

The present invention relates to a high modulus macroscopic fiber comprising single-wall carbon nanotubes (SWNT) and an acrylonitrile-containing polymer. In one embodiment, the macroscopic fiber is a drawn fiber having a cross-sectional dimension of at least 1 micron. In another embodiment, the acrylonitrile polymer-SWNT composite fiber is made by dispersing SWNT in a solvent, such as dimethyl formamide or dimethyl acetamide, admixing an acrylonitrile-based polymer to form a generally optically homogeneous polyacrylonitrile polymer-SWNT dope, spinning the dope into a fiber, drawing and drying the fiber. Polyacrylonitrile/SWNT composite macroscopic fibers have substantially higher modulus and reduced shrinkage versus a polymer fiber without SWNT. A polyacrylonitrile/SWNT fiber containing 10 wt % SWNT showed over 100% increase in tensile modulus and significantly reduced thermal shrinkage compared to a control fiber without SWNT. With 10 wt % SWNT, the glass transition temperature of the polymer increased by more than 40° C.

The invention provides a porous-carbon nano-fiber supported nano-grain catalyst and a preparation method thereof. A porous polyacrylonitrile-based carbon nano-fiber supported nano-grain catalyst is prepared by adopting an electrostatic spinning process, constant-tension hot stretching, preoxidation and chemical activation at a temperature between 500 and 1,000 DEG C. Porous-carbon nano-fiber has the diameter between 100 and 500 nanometers, the aperture between 1 and 500 nanometers, the porosity between 0.1 and 1.0 cm<3>/g and the specific surface area between 100 and 2,000 m<2>/g, and catalyst particles supported on the surface of the nano-fiber has the aperture between 1 and 100 nanometers and the weight percentage content between 1 and 40 percent. The preparation method has the advantage of simple process, and can prepare the porous-carbon nano-fiber supported nano-grain catalyst with high porosity, large specific surface area, strong adsorption activity and catalytic efficiency through the chemical activation at a low temperature.

A nonwoven web product including ultra-fine fibers is formed utilizing a spunbond apparatus that forms multicomponent fibers by delivering first and second polymer components in a molten state from a spin pack to a spinneret, extruding multicomponent fibers including the first and second polymer components from the spinneret, attenuating the multicomponent fibers in an aspirator, laying down the multicomponent fibers on an elongated forming surface disposed downstream from the aspirator to form a nonwoven web, and bonding portions of at least some of the fibers in the nonwoven web together to form a bonded, nonwoven web product. The multicomponent fibers can include separable segments such as islands-in-the-sea fibers, where certain separated segments become the ultra-fine fibers in the web product. In addition, carbon tubular fibers can be formed by extruding islands-in-the-sea fibers including polyacrylonitrile or pitch sheath segments in the fibers, separating the segments of the fiber, and converting the polyacrylonitrile or pitch to carbon by a carbonization process.

The invention relates to a method for preparing polyacrylonitrile-based carbon fiber with reinforced carbon nanometer tubes, which comprises the following steps: respectively dispersing and dissolving carbon nanometer tubes (CNT) and polyacrylonitrile (PAN) in dissolvent, obtaining PAN/CNT spinning solution through mixing the solution, obtaining PAN/CNT fiber through carrying out the wet-spinning method to the solution, then carrying out pre-oxidation and carbonization to the wet-spinning fiber to prepare the carbon fiber with reinforced carbon nanometer tubes. The mechanical property of the carbon fiber which is prepared by the method of the invention is obviously improved, and the prepared carbon fiber can be applied to the fields of reinforcing materials, conducting, electrostatic resistance, heat conducting and the like.

A polyacrylonitrile-based polymer, containing a polymer of which main component is acrylonitrile, which satisfies at least one kind requirement selected from the following [a] to [d].

[a] Z-average molecular weight (Mz) determined by gel-permeation chromatograph is 800,000 to 6,000,000 and degree of polydispersity (Mz/Mw) (Mw denotes weight average molecular weight) is 3.0 to 10.0.

[b] Z+1-average molecular weight (Mz+1) determined by GPC method is 3,000,000 to 10,000,000 and degree of polydispersity (Mz+1/Mw) is 6.0 to 25.0.

[c] Mzm determined by gel-permeation chromatograph multi-angle laserlight scattering photometry is 400,000 to 1,000,000 and degree of polydispersity (Mzm/Mwm) is 3.0 to 10.0.

[d] Z-average radius of gyration (Rz) determined by gel-permeation chromatograph multi-angle laserlight scattering photometry is 25 to 45 nm and its ratio to weight average radius of gyration (Rz/Rw) is 1.3 to 2.5.

Ceramic materials operable to repair a defect in bone of a human or animal subject comprising a porous ceramic scaffold having a bioresorbable coating, and a carrier comprising denatured demineralized bone. The ceramic may contain a material selected from the group consisting of hydroxyapatite, tricalcium phosphate, calcium phosphates, calcium carbonates, calcium sulfates, and combinations thereof. The compositions may also contain a bone material selected from the group consisting of: bone powder, bone chips, bone shavings, and combinations thereof. The bioresorbable coating may be, for example, demineralized bone matrix, gelatin, collagen, hyaluronic acid, chitosan, polyglycolic acid, polylactic acid, polypropylenefumarate, polyethylene glycol, or mixtures thereof.

The invention relates to a lithium ion battery composite cathode material and a preparation method. The cathode material comprises a hard carbon precursor material containing hetero atoms, and natural spherical graphite, wherein the hard carbon precursor material selects one or more than two of phenolic resin, polyfurfural, furan resin, polyvinyl alcohol, epoxide resin or polyacrylonitrile as raw materials, and accounts for 5 to 45 percent of the natural spherical graphite by mass; modifier of the hetero atoms is boron-containing modifier including boric acid and diboron trioxide, phosphor-containing modifier including phosphoric acid and phosphorus pentoxide, and nitrogen-containing modifier HNO3; and one of the modifiers accounts for 5 to 35 percent of the hard carbon precursor by mass. An analog battery formed by the cathode material which is prepared by the method has the capacity over 350 mAH/g and first coulomb efficiency up to 95.8 percent, and has good circulation performance. The preparation method has the advantages of low cost and simple process.

The invention discloses sulfenyl anode of a lithium-sulfur rechargeable battery and a preparation method thereof. The sulfenyl anode is prepared by the steps of: equally mixing sulfenyl compound active material, cyclodextrin binder and carbon conductivity agent, coating the mixture on an aluminum foil current collector and obtaining the sulfenyl anode after drying and pressing. The coating thickness is 50 to 100 microns and the aluminum foil thickness is 20 to 30 microns; the mass ratio of the sulfenyl compound active material, the cyclodextrin binder and the carbon conductivity agent is 7 to 8:0.6 to 1:0.6 to 1.5, wherein the sulfenyl compound active material is formed by the steps of: equally mixing carbon nano tube, sulfur and polyacrylonitrile according to the mass ratio of 0.1 to 0.2:6 to 8:1 and sintering the mixture in protection of inert gas at the temperature of 300 to 320 DEG C for insulation for 6 to 8 hours. By using the lithium-sulfur rechargeable battery with the sulfenyl anode and lithium metal cathode, the reversible capacity of the sulfenyl compound active material reaches 680mAh.g under 0.1C multiplying power charge-discharge condition; and compared with the discharge capacity of second circulation, the discharge capacity after 100 times of circulation decreases less than 10 percent.

The invention relates to a method for preparing graphene-reinforced polyacrylonitrile carbon fibers. The method comprises the following steps of: (1) preparing graphene or graphene oxide; (2) preparing a graphene/polyacrylonitrile spinning solution; (3) preparing graphene/polyacrylonitrile-based composite fibers; and (4) preparing graphene/polyacrylonitrile-based carbon. By the method, the dispersibility and interface bonding strength of the graphene oxide in a polymer matrix are effectively improved, and the comprehensive performance of the carbon fibers is further improved; the mechanical properties of the prepared carbon fibers are obviously improved, and the prepared carbon fibers can be used in the fields such as material reinforcement, electric conduction, anti-static electricity and heat conduction; and moreover, the preparation process is simple, easy to control and low in cost.

An intimate blend of staple fibers has from 10 to 75 parts by weight of at least one aramid staple fiber, from 15 to 80 parts by weight of at least one modacrylic staple fiber, and from 5 to 30 parts by weight of at least one polyamide staple fiber. The intimate blend of staple fibers provides yarns and fabrics that are flame retardant, also referred to as fire resistant, and can be used to make flame retardant articles, such as clothing. The flame retardant fabrics may have a basis weight from 4 to 15 ounces per square yard.

The invention discloses a composite diaphragm which comprises a supporting layer and an organic/inorganic particle blended coating layer, laminated; the coating layer comprises a polymer particle and an inorganic particle, uniformly mixed in an adhesive; micropore structures are arranged on the surface and at the inner part of the coating layer; the porosity is 20%-80%; the aperture average is 0.01 to 10 micrometers; the polymer particle comprises one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyimide, polyacrylonitrile and aramid fiber resin; the particle size of the polymer particle is 0.01-10 micrometers; the inorganic particle comprises any one or more of SiO2, Al2O3, CaO, TiO2, MgO, ZnO, SnO2 and ZrO2; the particle size of the inorganic particle is 0.01-10 micrometers; the mass ratio of the polymer particle to the inorganic particle is (1:10) to (10:1). The invention further discloses a method for preparing the composite diaphragm. The composite diaphragm and the method have good thermal safety and strong in electrolyte absorption stiffness value, and meanwhile, and can achieve the advantages of low cost and low pollution.

Provided is a sulfur-modified polyacrylonitrile manufacturing method that is characterized in that a starting base powder that comprises sulfur powder and polyacrylonitrile powder is mixed and the mixture is heated in a non-oxidizing environment while outflow of sulfur vapor is prevented. Also provided are a cathode for lithium batteries that uses, as the active substance, the sulfur-modified polyacrylonitrile manufactured with the method, and a lithium secondary battery that includes the cathode as a component element. This enables the practical use of an inexpensive sulfur-based material as the cathode material for lithium secondary batteries, and in particular, a sulfur-based cathode material that enables higher output and has excellent cycle life characteristics, as well as other characteristics, and secondary lithium batteries using the same can be obtained.

Provided is particulate of an anode active material for a lithium battery, comprising one or a plurality of anode active material particles being embraced or encapsulated by a thin layer of a high-elasticity polymer having a recoverable tensile strain no less than 5%, a lithium ion conductivity no less than 10⁻⁶ S/cm at room temperature, and a thickness from 0.5 nm to 10 μm, wherein the polymer contains an ultrahigh molecular weight (UHMW) polymer having a molecular weight from 0.5×10⁶ to 9×10⁶ grams/mole. The UHMW polymer is preferably selected from polyacrylonitrile, polyethylene oxide, polypropylene oxide, polyethylene glycol, polyvinyl alcohol, polyacrylamide, poly(methyl methacrylate), poly(methyl ether acrylate), a copolymer thereof, a sulfonated derivative thereof, a chemical derivative thereof, or a combination thereof.

An inflatable cushioning article is made by a process of extruding two multilayer films (or extruding one film which is either annular or folded over) each having (a) a seal layer, (b) a tie layer containing an anhydride modified olefin polymer containing anhydride at a level of at least 150 ppm, based on the weight of the modified olefin polymer, and (c) an oxygen barrier layer comprising crystalline polyamide, crystalline polyester, ethylene/vinyl alcohol copolymer, polyacrylonitrile, and/or crystalline polycycloolefin. Selected portions of the films are heat sealed to one another in a selected area providing a heat seal pattern which leaves inflatable chambers between the films, whereby an inflatable cellular cushioning article is produced. At some point after extrusion, at least one of the multilayer films are aged for a time and at a temperature in accordance with at least one member selected from the group consisting of: (i) 141° F. to 250° F. for a period of at least 1 second; (ii) 101° F. to 140° F. for a period of at least 10 minutes; (iii) 61° F. to 100° F. for a period of at least 1 hour; and (iv) 30° F. to 60° F. for a period of at least 1 day. After aging, the cellular cushioning article is inflated. Preferably, the article is inflated to an internal pressure of at least 1.5 psi.

The invention discloses a method for preparing polyacrylonitrile carbon fiber protofilament by dry and wet methods. The method comprises the steps of polymerization, demonomerization and defoaming, filtration, coagulation, washing and drafting, oiling densification, steam drafting, heat setting and drying. Three-level coagulating baths at the temperature of between 10 DEG C below zero and 70 DEG C and with dimethyl sulfoxide with concentration of 10 to 60 mass percent are adopted in the coagulation step, and the first coagulating bath contains aqueous ammonia accounting for 0.05 to 1 percent of the mass of the first coagulating bath; and a spinning head is subjected to 1.5 to 5 times positive drafting in the first coagulating bath, and the drafting is 0 in the second and third coagulatingbathes. According to the method for preparing the polyacrylonitrile carbon fiber protofilament, the spinning process is stable, the broken filament is little, the spinning speed is high, the spinningis stable, the prepared protofilament has few defects, the density is not less than 1.180g/cm<3>, and the tensile strength is not less than 7cN/dtex. The protofilament can be prepared into a high-performance carbon fiber with tensile strength of more than 4.9GPa and elastic modulus of between 260 and 280GPa by high-temperature carbonization.

The invention discloses a silicon-carbon composite material with nano micropores and a preparation method as well as application thereof. The material comprises nano-silicon (Si) particles and a carbon nanofiber matrix, wherein the nano-silicon particles are dispersed in the carbon nanofiber matrix; and nano pores and micropores communicated with the nano pores are distributed in the carbon nanofiber matrix. The method comprises the steps of dissolving the nano-Si particles and polyacrylonitrile (PAN) in a solvent to prepare a mixed spinning solution, then carrying out electrostatic spinning on the mixed spinning solution, and curing spinning trickles in a coagulating bath to obtain a porous PAN-Si composite nanofiber; and then carrying out oxidation and carbonization treatment in sequence to obtain the silicon-carbon composite material with a nano micropore structure. The silicon-carbon composite material is applied to preparation of lithium ion battery cathode materials. Compared with the prior art, the silicon-carbon composite material ensures the overall electron transport capacity of the material while reserving buffer space for expansion of the nano-Si particles.

The present invention is directed to the production of nanostructures, e.g., single wall carbon nanotubes (“SWNT”) and/or multi-wall carbon nanotubes (“MWNT”), from solutions containing a polymer, such as polyacrylonitrile (PAN). In particular, the invention is directed to the production of nanostructures, for example, SWNT and/or MWNT, from mixtures, e.g., solutions, containing polyacrylonitrile, polyaniline emeraldine base (PANi) or a salt thereof, an iron salt, e.g., iron chloride, and a solvent. In one embodiment, a mixture containing polyacrylonitrile, polyaniline emeraldine base or a salt thereof, an iron salt, e.g., iron chloride, and a solvent is formed and the mixture is electrospun to form nanofibers. In another embodiment, the electrospun nanofibers are then oxidized, e.g., heated in air, and subsequently pyrolyzed to form carbon nanostructures.

The invention discloses a method for preparing a carbon/carbon-silicon carbide composite material for bearings. The preparation method comprises the following steps: preparing a carbon fiber integral felt of 0.15-0.30g/cm<3> from polyacrylonitrile preoxidized fibers through puncture carbonization, or preparing a non-woven cloth carbon fiber integral felt of 0.4-0.6g/cm<3> from non-woven cloth and a mesh tyre through puncture carbonization in an alternating lamination manner; preparing C/C porous preform with density of 1.35-1.75g/cm<3> by adopting a chemical vapor infiltration (CVI) and resin precursor infiltration and pyrolysis (PIP) comprehensive process, and performing a high-temperature treatment at 2,250-2,600 DEG C in the Ar gas protective atmosphere; and vacuumizing, then introducing Ar gas, heating to 2,200-2,350 DEG C to perform liquid silicon infiltration, and preserving heat for 1.5 hours. The method is a preparation method of the carbon/carbon-silicon carbide (C/C-SiC) composite material with little residual silicon and low abrasion rate for bearings.

The invention discloses a preoxidation method for a polyacrylonitrile fiber of former body of carbon fiber. The method is, under normal pressure, to subject the polyacrylonitrile fiber precursor orderly and continuously to constant preoxidation, that is, preoxidation at five temperatures in a low temperature carbonization furnace, including a cyclization process under the protection of nitrogen at a first temperature and a second temperature with rigid drawing at the second temperature, and a oxidation crosslink process with the presence of air at a third temperature, a fourth temperature and a fifth temperature; to low temperature carbonization with nitrogen passing through the furnace at a sixth temperature; and finally to high temperature carbonization under the protection of nitrogen after entering a high temperature carbonization furnace through a tension bracket. The method has the advantages that in case of the protection of nitrogen gas, the heat treatment to fiber can improve the reactivity of the fiber, is favorable for the implement of cyclization reaction, and meanwhile in the case of the protection of nitrogen gas, the applied rigid drawing can improve the orientation degree of a molecular chain along the fiber axis, and thus polyacrylonitrile carbon fiber with higher strength and higher modulus can be obtained.

The invention discloses a method for preparing a carbon nanofiber-based non-noble-metal catalyst through oxidation improved electrostatic spinning in the technical field of carbon nanofibers and fuel cell catalysts. The method disclosed by the invention comprises the following steps: dissolving at least one transition metal salt and polyacrylonitrile in a solvent to form a precursor solution; carrying out electrostatic spinning on the precursor solution under certain parameter conditions to obtain iron-containing polyacrylonitrile nanofibers; and heat treating the iron-containing polyacrylonitrile nanofibers in an atmosphere containing a small amount of oxidizing gas to obtain carbon nanofibers containing transition metal and nitrogen element and improved by the small amount of oxidizing gas. According to the method, the cost of the raw materials is low, the operation is convenient and controllable, the operation is easy, the surface structure of the catalyst can be regulated and controlled, and the prepared oxidation improved carbon nanofiber based non-noble-metal catalyst has good catalytic activity on oxygen reduction reaction. The whole preparation process can be combined with a traditional carbon fiber technique, and the method has a prospect that large scale and industrialization of the non-noble metal catalyst can be realized.

The invention relates to a method for preparing a polyacrylonitrile carbon fiber precursor. The method comprises the following steps of: copolymerizing acrylonitrile and copolymerization components in multicomponent solution so as to form polymer spinning stock solution which has a relatively uniform and controllable molecular structure, performing demonomerization on the spinning stock solution,defoaming, filtering, and preparing the polyacrylonitrile carbon fiber precursor by a dry-jet wet-spinning process. The key technology of the method is that: a gas storage box is arranged on a dry wet spinning pack, the gas storage box and the liquid level of coagulating bath fluid form a dry-jet wet-spinning air layer into a confined space, and ammonia is persistently aerated into the space to carry out gas-liquid reaction with spinning solution trickle in the air layer. The polyacrylonitrile precursor prepared by the method has regular sections and few defects, the density is not less than 1.187g/cm<3>, the density after carbonization is not less than 1.79g/cm<3>, the strength is not less than 5.1GPa, and the modulus of elasticity is 280 to 300GPa.

The invention provides an amidoxime-based chelate polyacrylonitrile fiber and its preparation method. The preparation method of the amidoxime-based chelate polyacrylonitrile fiber comprises the following steps that 1, polyacrylonitrile fibers are subjected to irradiation cross-linking under the conditions of an inert gas atmosphere and an irradiation amount of 20 to 2000kGy; and 2, the polyacrylonitrile fibers subjected to irradiation cross-linking undergo an amidoximation reaction. The invention also provides a use of the amidoxime-based chelate polyacrylonitrile fiber as a metal ion adsorption material. Through the preparation method which is simple relatively, the amidoxime-based chelate polyacrylonitrile fiber which has good mechanical properties, high fiber breaking strength, a long reuse life and stable performances and is damaged difficultly is obtained. The amidoxime-based chelate polyacrylonitrile fiber can be utilized as a metal ion adsorption material, is suitable for the fields of purification of industrial waste water or slag, or extraction of uranium of seawater, has excellent effects of adsorbing multiple metal ions, and can greatly reduce an industrial cost.

The invention discloses a preparation method of polyacrylonitrile/graphene composite-based carbon fiber, which comprises the following steps: firstly preparing a polyacrylonitrile mixed solution uniformly dispersed with graphene through an in-situ polymerization method, and then employing the mixed solution as a spinning solution and obtaining a polyacrylonitrile/graphene composite protofilament by a wet spinning or dry-jet wet spinning process, and finally making the protofilament subject to a pre-oxidation treatment and a carbonization treatment to obtain the polyacrylonitrile/graphene composite-based carbon fiber. Compared with the existing polyacrylonitrile-based carbon fiber, the carbon fiber prepared by the method of the invention has a significantly increased mechanical property, and the carbonation yield in the preparation process is improved, therefore, the preparation method is an efficient and reliable preparation method with good application prospects.

The invention relates to a making method of polyacrylonitrile carbon fiber, comprising: (1) mixing polyacrylonitrile and solvent according to the solid content of 0.1%-25% in a reactor, heating and stirring to completely dissolve the polyacrylonitrile and solvent; (2) after dissolving completely, adding KMnO4, then adding gas with oxide, processing pre-oxidation for the spinning solution; pre-oxidizing at temperature of 90-250 DEG C for 1-2h; reaching different pre-oxidation effect under different pre-oxidation temperatures and different pre-oxidation time; (3) spinning the spinning solution in the step (2) in a spinning machine, then obtaining pre-oxidation filaments with good pre-oxidation degree after water washing, drafting and heat forming; then obtaining high-property carbon fiber through carbonization. The method in the invention carries out innovation for pre-oxidation stage of carbon fiber with convenient operation, simple equipment but rarely pollution for the environment; low-cost controllable pre-oxidation of polyacrylonitrile is implemented and the skin-core structures are reduced, thereby being capable of producing high-property carbon fiber; and the preparation method greatly reduces the production cost of carbon fiber.