66results about How to "Raise the degree of orientation" patented technology

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 relates to a curing treatment method of a carbon fiber precursor polyacrylonitrile fiber. The method comprises the following steps: pre-cyclizing the polyacrylonitrile fiber precursor in the atmosphere of inert gas; carrying out cyclizing and plastic drawing in the atmosphere of inert gas and water vapor; and carrying out oxidation crosslinking in the atmosphere of air, thus obtaining a pre-oxidized polyacrylonitrile fiber. The method has the following beneficial effects: carrying out heat treatment on the fiber in the inert atmosphere is beneficial to implementation of cyclization reaction in the molecules to form rigid ladderlike molecules with regular structure and strong heat resistance, and at the same time, a defined amount of water vapor is introduced to obtain a higher drawing ratio by enhancing the plasticity of the molecular chains in the fiber, thus improving the orientation degree of the rigid molecules along the fiber axis.

A ceramic sheet 20 is produced by a method in which inorganic particles including, as a main component, an oxide represented by general formula ABO₃ and containing a volatile component are mixed such that the A/B ratio is 1.05 or more, the inorganic particles are formed into a self-supported planar shaped body with a thickness of 30 μm or less, and the shaped body is fired, without an inactive layer or with an inactive layer which does not substantially react with the shaped body and is disposed adjacent to the shaped body, at a temperature-rising rate of 30° C./min or more in a temperature range which is equal to or higher than a temperature at which the volatile component is volatilized.

The invention discloses a heat-conducting graphite membrane and a preparation method. The heat-conducting graphite membrane is prepared from 90 to 99.7 wt% of a graphene nanosheet and 0.3 to 10.0 wt% of an inorganic adhesive. The preparation method comprises the following steps: 1) with the graphene nanosheet as a raw material, adding an aqueous inorganic adhesive material to wet the graphene nanosheet and carrying out uniform mixing with stirring; 2) adding a mixed wet material into a rolling unit for calendaring so as to obtain the heat-conducting graphite membrane; and 3) drying the calendared heat-conducting graphite membrane. The preparation method is a novel preparation method for the heat-conducting graphite membrane, can be carried out with a traditional rolling unit to prepare the heat-conducting graphite membrane and has low requirements for the unit, and a rolling process is simple; the prepared graphite membrane has a few air gaps, uniform compactness and high heat conduction performance at two directions respectively parallel and perpendicular to the graphite membrane.

The invention discloses an electrostatic spinning collecting device and a preparation method of nanofiber adopting a gradient-oriented structure. The electrostatic spinning collecting device consists of a power supply, a forward and reverse rotation controller, motors, magnets and receiving heads. The preparation method comprises the following steps: dissolving a solute such as polycaprolactone into a mixed solution of dichloromethane and N-N dimethylformamide, uniformly stirring, and adjusting the spinning positive voltage to be 10-20 kV, the negative pressure to be -5 kV to 0 kV, the distance between a needle head and the electrostatic spinning collecting device to be 10-20 cm, and the distance between the two conical receiving heads to be 0.5-7 cm. In the spinning process, parallel fibers are deposited between the receiving heads, while the fibers deposited at the receiving heads are randomly oriented, and a transitional area exists in the middle. Through the electrostatic spinning collecting device and the preparation method, a nanofiber stent adopting the gradient-oriented structure can be obtained; the nanofiber stent adopting the gradient-oriented structure has relatively high mechanical strength, simulates an arrangement mode of collagen fibers in a muscle tendon and a ligament tissue, and can be applied to tissue engineering and tissue repair of the muscle tendon and the ligament.

The invention relates to a highly-oriented highly-heat-conducting carbon/carbon composite material and a preparation method thereof. The technical scheme is as follows: the method comprises the following steps of: oxidizing and stabilizing large-section strip-shaped intermediate phase pitch fiber which serves as a raw material; uniformly coating an adhesive on the surface of the oxidized and stabilized strip-shaped intermediate phase pitch fiber, wherein the adhesive accounts for 4 to 20wt% of raw materials; tiling the strip-shaped intermediate phase pitch fiber coated with the adhesive is coated in a mold in a unidirectional mode and performing hot-forming; and finally, carbonizing at the temperature of between 1,000 and 1,600 DEG C and graphitizing at the temperature of between 2,800 and 3,100 DEG C, so as to obtain the highly-oriented highly-heat-conducting carbon/carbon composite material. In the scheme, the cross section of the large-section strip-shaped intermediate phase pitch fiber has a shape of an approximate rectangle which has the width of 1 to 2 millimeters and the thickness of 8 to 20 microns; the hot-forming temperature is 300 to 700 DEG C; the hot-forming pressure is 5 to 20MPa, and the temperature and the pressure are kept for 1 to 24 hours. The method has the advantages of being simple in preparation process, low in cost, high in repeatability and short in production cycle, and the composite material prepared by using the method has the highly-oriented and highly-heat-conducting characteristics.

The invention relates to a mesophase pitch raw mateiral for preparing high-modulus high-thermal-conductivity carbon fiber, and a preparation method thereof. With a polarizing microscope measuring method, a mesophase content of the mesophase pitch raw material is 100%. With a capillary rheometer measuring method, a softening point of the mesophase pitch raw material is 220-260 DEG C. With an X-ray diffraction measuring method, an aromatic hydrocarbon macromolecule average sheet piling thickness Lc of the mesophase pitch raw material is larger than 8nm. According to the invention, a naphthalene series compound such as methylnaphthalene is adopted as a raw material; hydrogen fluoride-boron trifluoride is adopted as a catalyst; and through controlling a catalyst dose, polymerization conditions and low-boiling-point product separation conditions, the mesophase pitch is prepared. Compared with prior arts, the mesophase pitch provided by the invention has excellent spinnability, such that spinning process controlling and operation are facilitated. The mesophase pitch has good molecular orientation, such that high-modulus high-thermal-conductivity carbon fiber with high orientation degree can be prepared under a relatively low graphitization temperature. Therefore, the production cost of high-performance carbon fiber is greatly reduced.

The invention discloses a method and device for preparing magnetostrictive material, which belong to the technical field of materials. The method comprises the following steps: (1) smelting to prepare Tb-Dy-Fe master alloy or Tb-Fe master alloy; (2) putting the master alloy in a crucible in a heating furnace, applying a balanced magnetic field, and heating the master alloy to obtain semi-solid material in the presence of a magnetic field and inert gas for isothermal treatment; and (3) in the presence of inert gas, cooling to 900+/-5DEG C; then cooling to normal temperature to obtain the Tb-Dy-Fe or Tb-Fe magnetostrictive material. The device comprises a strong magnet, a heating furnace, a crucible, a bracket and a cooling medium container, wherein the lower end of the bracket is fixed on the bottom plate of the heating furnace; the bottom plate of the cooling medium container is in slip connection with the outer wall of the bracket; the cooling medium container is positioned between the crucible and the bottom plate of the heating furnace; and the bottom surface of the cooling medium container is connected with a gas-driven lifting device. With the method disclosed by the invention, the orientation degree of TbFe2 or (Tb, Dy)Fe2 in the alloy in (111) direction can be obviously improved. The device is simple to operate.

The invention belongs to the technical field of high molecular materials and particularly relates to a multilayer insulation thermal interface material and a preparation method thereof. The multilayerinsulation thermal interface material is an interface material which is formed through alternate distribution of insulation heat conduction layers and conductive heat conduction layers and is of a multilayer structure, wherein the insulation heat conduction layers are prepared by filling a ceramic-base heat conduction filler with silicone rubber, and the conductive heat conduction layers are prepared by filling a carbon-base heat conduction filler with silicone rubber; and the multilayer structure comprises 2n layers, and n is more than or equal to 1. The insulation thermal interface materialhas the multilayer structure, relatively high heat conductivity coefficient (reaching 6W/mK-11W/mK) and excellent electrical insulating property (volume resistivity reaches 10<11>ohmcm-10<13>ohmcm),disruptive strength (5KV/mm-9KV/mm) and mechanical property.

A method for producing a crystallographically oriented ceramic according to the present invention includes a preparation step of preparing a template layer having uniform crystal orientation in a predetermined direction, a formation step of forming a shaped body including a matrix layer arranged on the template layer, the matrix layer being composed of a mixed material that contains a lead-containing material and an additional material containing lithium and boron, and a firing step of firing the shaped body formed in the formation step at a predetermined firing temperature. Furthermore, after the firing step, a post-annealing step of heating the shaped body to remove lithium and boron may be included.

The invention relates to the technical field of lithium battery separators and provides a dry unilateral-stretching production technology of a lithium battery separator. The dry unilateral-stretchingproduction technology of the lithium battery separator solves the problem that the hole size distribution of a lithium battery separator produced in the prior art is uneven. The dry method unilateralstretching production technology of the lithium battery separator comprises the following steps of (1) preparing materials, wherein polypropylene and ethylene-propylene copolymer are used as raw materials, pre-dried respectively and then put into a high-speed mixer to be stirred to uniform; (2) conducting melt extrusion, wherein the evenly mixed raw materials are fed into an extrusion machine andplastified into uniform melt, and the uniform melt is extruded from a slit die; (3) conducting tape casting film formation, wherein the melt undergoes tape casting and then forms a polypropylene basefilm, and the polypropylene base film undergoes traction and coiling; (4) conducting annealing treatment, wherein the coiled polypropylene base film is placed in a drying box to undergo annealing treatment; (5) conducting unilateral stretching, wherein the annealed polypropylene base film undergoes cold stretching and hot stretching; and (6) conducting heat setting, wherein heat setting is conducted on the polypropylene base film completing unilateral stretching, and after cooling and coiling, the lithium battery separator is obtained.

Provided is a stretched laminate for manufacturing a thin polarizer while increasing the degree of orientation of a polyvinyl alcohol-iodine complex without problems such as breakage. In addition, there are provided a method of manufacturing a thin polarizer having superior optical characteristics by using the stretched laminate, a thin polarizer manufactured by the method, and a polarizing plate including the thin polarizer.

The invention relates to the technical field of functional film materials, and in particular relates to a graphitized film and a preparation method and application thereof. The preparation method of the graphitized film comprises: (1) low temperature in-situ polymerization of a diamine monomer and a dianhydride monomer; (2) film casting of an obtained mixed solution; (3) in-sequence drawing treatment and heating imidization of an obtained graphene/polyamic acid composite film; (4) and in-sequence heating carbonization and heating graphitization of an obtained graphene/polyimide composite film.Edge-functionalized graphene is used as a filler, and the graphene/polyamic acid composite film is appropriately drawn to improve the orientation and regularity of the composite film, and so that theobtained graphitized film has high directivity, high conductivity and high thermal conductivity, and is expected to be better applied in microelectronic packaging, electromagnetic shielding, heat dissipating materials, electrode materials and other aspects.

The invention provides a directional heat conduction material as well as a preparation method and application thereof. The directional heat conduction material comprises a polymer matrix and anisotropic heat conduction fibers filled in the polymer matrix, the anisotropic heat conduction fibers are directionally arranged in the polymer matrix, and the anisotropic heat conduction fibers are orientedalong the directional arrangement direction. The directional heat conduction material at least has the following beneficial effects: the directional heat conduction material utilizes the anisotropicheat conduction fillers to form directionally arranged heat conduction fibers, and the heat conduction fibers are also oriented along the arrangement direction of the heat conduction fibers on the microscale, so that the heat conduction material can utilize the anisotropy of the fillers to the greatest extent; the orientation degree of the fillers is greatly improved, the high heat conduction performance can be achieved with the low proportion of the anisotropic heat conduction fillers, and the heat dissipation requirement brought by high-speed development of electronic devices is further met.

The invention belongs to the technical field of composite material optics, and discloses a preparation method and application of a composite film. The composite film provided by the invention mainly comprises a polymer and a carbon nanotube. The method comprises the steps of carrying out surface modification on the carbon nanotube; uniformly mixing the polymer, the modified carbon nanotube and a solvent to obtain a mixed solution; obtaining an oriented polymer/carbon nanotube composite fiber film through an electrostatic spinning method; and annealing and setting the dried composite fiber film through the solvent to form a film, and then carrying out stretching and secondary orientation to obtain the product. The oriented carbon nanotube composite film provided by the invention has the advantages of various selectable raw material types, simple process and large-scale preparation, thereby having very good application prospects in the fields of liquid crystal display, imaging and the like.

The invention provides a method for preparing a longitudinal high-thermal-conductivity gasket by orienting carbon fibers through a controllable compression deformation method, which is characterized in that the carbon fibers are orientated and arranged through the controllable compression deformation method, and the carbon fiber silica gel gasket with the thermal conductivity of 30W/mK in the thickness direction is prepared through the subsequent processes of defoaming, vulcanizing, cutting, surface treatment and the like. The carbon fiber gasket with the length-width ratio of 20: 1 can be prepared, the production efficiency is improved, and meanwhile waste materials are reduced.

The invention provides a heat-conducting composite material as well as a preparation method and application thereof. The preparation method of the heat-conducting composite material comprises the following steps of S1, mixing a filler and a polymer matrix to obtain slurry; S2, forming a first composite film from the slurry by a thin film forming process; S3, winding the first composite film to form a first cylinder; S4, enabling the first cylinder to form a second composite film by the thin film forming process, and winding to subsequently form a second cylinder; and S5, pressurizing and curing the second cylinder, wherein the filler comprises a two-dimensional heat-conducting sheet. According to the preparation method, a high-heat-conducting composite material is prepared in the manner that a thin film is curled and then pressurized for forming; the two-dimensional heat-conducting sheet adopted in the course of forming the thin film is arranged in the plane direction of the thin filmunder the action of pressure and/or shearing force; a pressure influence caused by pressurization is enhanced by repeating a curling step and an extrusion step; the two-dimensional heat-conducting sheet is oriented as much as possible; the anisotropic heat conduction performance of the two-dimensional heat-conducting sheet is fully utilized; and a higher heat conductivity is obtained.

The invention discloses an oriented honeycomb wave-absorbing material and a preparation method thereof, and belongs to the technical field of electromagnetic wave functional materials. The preparation method comprises the following steps: (1) dipping treatment of a honeycomb base material: dipping the honeycomb base material in magnetic absorbent slurry to obtain a honeycomb material coated with a magnetic wave-absorbing coating; and (2) orientation and molding of the honeycomb material: rotating the honeycomb material coated with the magnetic wave-absorbing coating in a magnetic field for 6-12 hours, and then heating and curing to obtain the oriented honeycomb wave-absorbing material. An impregnation method and a magnetic field induction method are combined, on the basis of an existing honeycomb structure wave-absorbing material, the spatial arrangement of the absorbent on the honeycomb wall is changed by applying a magnetic field, the orientation degree of the absorbent is improved, the obtained honeycomb material has remarkably improved magnetic loss, and especially in a P frequency band, and the low-frequency absorption performance of the wave-absorbing material is effectively improved.

The invention relates to the field of magnetic materials, in particular to a preparation method of a neodymium iron boron magnetic material and the magnetic material prepared by adopting the method. The preparation method of the neodymium iron boron magnetic material comprises the following steps of: weighing raw materials; smelting the raw materials, pre-cooling the smelting liquid, preserving the heat, and performing melt-spinning to obtain a melt-spunning sheet; carrying out hydrogen demolishing, powdering and molding orientation on the melt-spinning sheet to obtain a blank; and sintering and tempering the blank to obtain the neodymium iron boron magnetic material. The neodymium iron boron magnetic material is prepared by adopting the preparation method. The magnet is made of the neodymium iron boron magnetic material. According to the preparation method, praseodymium-neodymium alloy is partially replaced by metal cerium and gadolinium-iron alloy, and meanwhile, the smelting liquid is pre-cooled and subjected to heat preservation before melt-spinning. Through cooperative implementation of the measures, the cost of the neodymium iron boron magnetic material is reduced, meanwhile, thereby guaranteeing that the neodymium iron boron magnetic material has good performance, and the requirements of actual use can be met.

The invention discloses an oriented silicon steel with excellent magnetic properties and a manufacturing method thereof. The present invention obtains the oriented silicon steel with excellent magnetic properties by controlling the area ratio of small crystal grains of D<5 mm in an oriented silicon steel finished product to be not more than 3%, and controlling the ratio μ17/μ15 of the magnetic conductivity under the magnetic induction of 1.7 T and 1.5 T in the oriented silicon steel finished product to be 0.50 or more. In addition, by using a slab of the oriented silicon steel with suitable components and an optimized cold rolling step, the present invention effectively decreases the heating temperature of the slab and the production cost thereof, and simultaneously better controls the size and ratio of the crystal grains in the oriented silicon steel finished product and the magnetic conductivity in a certain range of magnetic induction, ensures that secondary recrystallization has good Goss texture orientation and finally, stably obtains the oriented silicon steel product with excellent magnetic properties.

The invention generally relates to unitized packages for containing and dispensing a product material. In particular, the unitized packages comprise a printed base card and a fluid vessel permanently bonded to the printed base card. The fluid vessel comprises a first laminate barrier layer comprising at least one layer of a biaxially oriented thermoplastic polymer, a portion of which is formed into a modified dome shape, and a planar second laminate barrier layer. The first and second laminate barrier layers are sealed together to form a fluid-tight enclosure, wherein the product material substantially fills the enclosure and the modified dome shape is resiliently sustainable. A method of manufacturing the unitized packages as described above is also provided. In particular, the method includes forming a portion of the first laminate barrier layer comprising the biaxially oriented polymer into the modified dome shape using a force such as pressurized gas.

The invention relates to a method of controlling the crimp shrinkage of a fine-denier polyester by adjusting the content of pentaerythritol. The method is characterized by comprising the following steps: adjusting the irregularity of molecular chains of polyester fibers by means of a branching effect of the pentaerythritol to a molecular chain of PET (Polyethylene Terephthalate) so as to change the flexibility of the molecular chains of the fibers; and finally, controlling the crimp shrinkage of the fine-denier polyester. On one hand, the method provided by the invention can greatly increase the crimp shrinkage of polyester filament yarns (from 25-38% to 40-46.7%), and on the other hand, the method can adjusts the crimp shrinkage of the fibers according to the filament number of the fibers by means of adjusting the content of the pentaerythritol, so that the fibers with different filament numbers are close in crimp shrinkage under a same draw texturing process condition, and thus, technical changes caused by switching production are simplified and the stability of fiber production is improved.