123results about How to "Lower percolation threshold" patented technology

The invention discloses a polyamide/graphite composite material with high conduction performance and a preparation method thereof. The composite material consists of a polyamide substrate and nanometer graphite and is prepared through in-situ polymerization. The nanometer graphite has high diameter-to-thickness ratio; and an effective conduction network can be formed in a polymer by using little nanometer graphite. With the low content of a conduction filling of the nanometer graphite, a conduction polymer material keeps original good mechanical performance. The volume conductivity of the polyamide/graphite composite material with high conduction performance can reach 8*10S/cm; and compared with a conventional natural graphite and expanded graphite conductive composite material, the polyamide/graphite composite material has excellent properties of low filling amount and high conductivity.

The invention discloses a making method of conductive composite material with positive-temperature coefficient effect, which comprises the following steps: (1) putting two blending polymers and conductive filler in the double-screw squeezing machine or sealed fusing machine to fuse 5-20 min with fusing temperature higher than fusing point of polymer by 10-50 deg.c; (2) moulding the blending material into film in the flat sulfurized machine.

The invention discloses electroconductive slurry and a preparation method thereof, and a printed circuit material. The electroconductive slurry comprises a polymer resin matrix and metal powder which is dispersed in the polymer resin matrix and serves as an electroconductive filler, wherein the microstructure of the metal powder is a three-dimensional dendritic metal crystal structure; the diameter of the metal crystal structure is 0.5-50 microns; a second-stage dendritic structure is 5 nanometers- 5 microns long. According to the electroconductive slurry and the preparation method thereof which are disclosed by the invention, the metal powder with the three-dimensional dendritic metal crystal structure serving as the microstructure is used as the electroconductive filler, so that the percolation threshold value of the electroconductive slurry can be greatly reduced, and the higher electroconductivity can be realized with less metal filler; furthermore, the metal powder with the three-dimensional dendritic metal crystal structure serving as the microstructure is used as the electroconductive filler, so that the electroconductive slurry can keep a high isotropous electroconduction effect and uniform dispersion; due to a nano-end structure, the resistivity of the electroconductive slurry can be greatly reduced, and the electroconductivity can be improved.

The invention provides a conductive polymer composite and a preparation method thereof. The conductive polymer composite comprises 100 parts by weight of matrix and 0.01-1.5 parts by weight of conductive nanofiller, wherein the matrix is an incompatible polymer blend system with dual-continuous structure, and the length-diameter ratio of the conductive nanofiller is greater than or equal to 100. Compared with a conductive fibering polymer composite prepared from carbon black, polyethylene and polyethylene terephthalate in the prior art, the conductive polymer composite has the advantages that firstly, the length-diameter ratio of the conductive nanofiller adopted in the conductive polymer composite is larger, so that the insulated polymer can conduct electricity by few addition of the conductive nanofiller, thus the conductive percolation threshold of the conductive polymer composite is reduced; secondly, the matrix of the dual-continuous structure and the conductive polymer nanofiller are distributed on a two-phase interface of the incompatible polymer blend system with the dual-continuous structure, so that the conductive percolation threshold of the conductive polymer composite is reduced; and finally, the preparation method provided by the invention is simple, safe and environment-friendly.

The invention relates to a preparation method of a graphene/silicon rubber pressure-sensitive conductive composite and belongs to the technical field of composite preparation. The preparation method comprises the following steps: dispersing the graphene used as a packing into a silicon rubber matrix by using an ultrasonic-assisted solution mixing method, and furthermore, preparing the graphene/silicon rubber pressure-sensitive conductive composite by using a high-temperature sulphidization method. The graphene has a high diameter-thickness ratio, and a conductive network can be formed in silicon rubber by using a relatively small quantity of graphene through the ultrasonic-assisted solution mixing and high-temperature sulphidization methods, so that the percolation threshold of the graphene/silicon rubber composite is relatively low; in addition, the system is sensitive to pressure so as to achieve a remarkable positive piezoresistive effect. The composite provided by the invention is widely applied to the fields of antistatic rubber, electromagnetic shielding products and pressure sensors.

The invention discloses a method for preparing a nanocomposite hybrid multi-dimension material, which belongs to the technical field of the low-cost manufacturing of resin-based composite materials. The method comprises the following steps of: adding a nanometer material into resin to prepare a nanocomposite resin substrate; and preparing the hybrid multi-dimension composite material by adopting a liquid molding process, wherein the dispersion of the nanometer material in the resin and the subsequent molding process are both performed in an ultrasonic field. As the nanometer material has an extremely large specific surface area and an extremely high length-diameter ratio, the threshold of the percolation of the nanometer material in the composite material is relatively lower, and the addition of 0.1 to 1.5 percent of the nanometer material is insufficient to influence the liquid molding process of the composite material, which does not influence the tensile property mainly determined by reinforcing fibers at the same time of greatly improving the mechanical property, conductivity and glass-transition temperature, mainly determined by the substrate, in the composite material.

The invention discloses a conductive and antistatic nylon which adopts polyamide resin as basic material and adds nano inorganic filling material, conductive carbon black, a lubricating agent, a surface processing agent and an antioxidant and the like; the part by weight ratio of all the components is as follows: 60 parts to 98 parts of polyamide resin, 1 part to 15 parts of nano inorganic filling material, 5 parts to 30 parts of conductive carbon black, 0.1 part to 1.0 part of lubricating agent, 0.1 part to 1.0 part of surface processing agent and 0.1 part to 0.5 part of antioxidant; the invention adds the conductive carbon black in the polyamide resin to improve the conductive effect of the material, reduces the using amount of the carbon black under the premise of guaranteeing the same conductivity and antistatic electricity and effectively improves the cost performance of the material, effectively improves the dispersion of the carbon black, and reduces the 'percolation threshold' of plastic; and the nano material is added into the nylon and has the effect of a nucleating agent, which has obvious strengthening and toughening effects to matrix resin and improves the comprehensive performance of the product.

The invention discloses resource-renewable and biodegradable conductive fiber and a preparation method thereof. The fiber consists of the following raw materials in parts by weight: 30-70 parts of polylactic acid (PLA), 30-70 parts of poly(3-hydroxybutyric acid-co-3-hydroxyvalerate (PHBV) and 0.05-8 parts of conductive filler. The preparation method of the conductive fiber comprises the following steps of: (1) proportionally pre-mixing PHBV (if PLA is not less than 50 parts) or PLA (if PLA is less than 50 parts) and the conductive filler, and performing melt blending and granulation to obtain the conductive master batch of the PHBV or PLA; (2) proportionally pre-mixing the PLA or PHBV and the conductive master batch of the PHBV or PLA, and performing melt blending and granulation to obtain composite conductive mater batches; and (3) spinning and drafting the composite conductive master batches one by one to obtain the conductive fiber. The conductive fiber disclosed by the invention can be used as the material for electrodes, static resistance, low-temperature heating, electromagnetic shielding, thermal sensitivity, gas sensitivity and the like.

The invention relates to a method for preparing a graphene composite with a low percolation threshold value and high heat stability. The method comprises the following steps: introducing double bonds by the grafting of graphene oxide with a silane coupling agent; polymerizing preliminarily-modified fillers with styrene and methyl methacrylate fine emulsion, and preparing modified fillers of grafting random copolymers; mixing the modified fillers with polystyrene and a poly methyl methacrylate solution, and using hydrazine hydrate for synchronous reduction; precipitating polymers, drying and performing. TEM tests for the graphene composite provided by the utility model show that part of fillers are distributed at two phases of interfaces and generates good compatibilization to a system, and the percolation threshold value is only 0.11 vol%. Meanwhile, SEM tests show that phase coarsening is inhibited before and after heat treatment, the heat stability of the system is obviously increased, and the graphene composite can be widely used in the field of conductive polymer composites.

The invention discloses an electric conductive/ magnetic conductive chemical fiber magnetic field induction spinning assisting forming device and a production method thereof. The electric conductive/ magnetic conductive chemical fiber magnetic field induction spinning assisting forming device and the production method thereof are characterized in that an electromagnetic coil (3) is vertically connected with a spinneret plate (2), the spinneret plate (2) is connected with a melt runner (1), the hollow portion of the electromagnetic coil (3) is in alignment with the center of the spinneret plate to enable fiber stripes (5) to successfully pass through the hollow portion of the electromagnetic coil, the electromagnetic coil is connected with a direct current power source in spinning, and then magnetic lines of force (4) are generated; then melt blending is conducted on magnetic powder, a dispersing agent, an antioxidant and polymer, the blended melting body is extruded out by a spinneret orifice through a metering pump, under the action of the magnetic field of the electromagnetic coil, magnetic particles are arrayed in the directions of the magnetic lines of force to form microfibers or string bead structures, the fiber stripes are cooled and solidified, and then oil applying, concentration of beams, drafting and heat shaping are conducted on the fiber stripes, and then the finished electric conductive/ magnetic conductive complex fibers are obtained.

The invention discloses a high-electrodeformation dielectric elastomer composite and a preparation method thereof. A polystyrene-b-poly(n-butyl acrylate)-polystyrene triblock copolymer is taken as a dielectric elastomer matrix, a method of direct emulsion blending of a graphene oxide water dispersion liquid and polystyrene-b-poly(n-butyl acrylate)-b-polystyrene emulsion is implemented, drying is performed at the room temperature, a dielectric elastomer composite film of graphene oxide/polystyrene-b-poly(n-butyl acrylate)-b-polystyrene is prepared, and a partially reduced graphene oxide/polystyrene-b-poly(n-butyl acrylate)-b-polystyrene dielectric elastomer composite is obtained through heat reduction. The adding amount of graphene and the elasticity modulus of the composite are effectivelyreduced, the dielectric property of the dielectric elastomer composite is improved, and the maximum electrodeformation of the partially reduced graphene oxide/polystyrene-b-poly(n-butyl acrylate)-b-polystyrene high-performance dielectric elastomer composite under the condition of no prestretching can be up to 21.3%.

The invention discloses a 3D printed wire rod with a functionalized skin-core structure and a preparation method thereof. The preparation method comprises the following steps: (1) coating a functionalauxiliary agent with a coupling agent; (2) subjecting the functional auxiliary agent coated with the coupling agent and a flexible polymer to twin-screw melt blending to obtain functional masterbatch; and (3) subjecting the functional masterbatch and PLA to single-screw blending extrusion. The 3D printed wire rod obtained in the invention has a skin-core structure; the flexible polymer is used asa skin layer, the PLA is used as a core layer, and the functional auxiliary agent is mainly dispersed in the skin layer and is immobilized on the surface of the device by fusion deposition melting (FDM); and the preparation method is simple and efficient, reduces the percolation threshold of the functional auxiliary agent and realizes multi-functionality of 3D printed devices.

The invention provides a positive plate and a lithium ion battery containing the positive plate. The safety of the battery cell is improved by controlling the seepage thresholds of the safety coatingcoating the surface of the positive current collector and the positive active material layer, and meanwhile, relatively high energy density and excellent electrical properties are ensured. Particularly, the seepage threshold value of the positive active material layer is small, and the addition amount of the conductive agent is small, so that a good electron path can be ensured, and the energy density of the positive plate can be increased.

The invention discloses a preparation method of a high-dielectric polyimide/calcium copper titanate nanowire composite material. The composite material is prepared by using polymer as a substrate. The method comprises the following steps: carrying out ultrasonic dispersion on calcium copper titanate nanowires in anhydrous ethanol, blending with a polyimide monomer in a solvent, and carrying out in-situ polymerization reaction on the monomer at room temperature while implementing copolymerization of polyimide and intercalation compounding with calcium copper titanate nanowires; and carrying out gradient annealing on the stock solution by a coating process to obtain the polyimide/CCTO nanowire composite film. Compared with pure polyimide, the dielectric constant of the polyimide/calcium copper titanate nanowire composite material is enhanced by 25 times, the dielectric loss is lower (0.015), and thus, the polyimide/calcium copper titanate nanowire composite material has wide application prospects in the fields of high energy storage capacitors, artificial organs, high speed integrated circuits and the like.

The invention discloses a preparation method for an electromagnetic shielding PP thin film. The preparation method for the electromagnetic shielding PP thin film comprises the following steps in sequence that 1, PP raw materials are made to a PP melt-blown nonwoven fabric by a melt-blown spinning technology; 2, a PP composite conductive fiber net modified by carboxylic multi-walled carbon nanotubes (c-MWCNTs) is prepared; and 3, the electromagnetic shielding PP thin film is prepared. The preparation method for the electromagnetic shielding PP thin film uses the carboxylic multi-walled carbon nanotubes (c-MWCNTs) to modify the PP melt-blown nonwoven fabric so as to prepare and obtain the PP composite conductive fiber net, and the PP composite conductive fiber net and a PP film are subjectedto hot pressing combination to prepare the high-performance PP electromagnetic shielding thin film; and the PP composite film is high in shielding effectiveness, and is suitable for being applied tothe field of thin films.

The invention discloses a preparation method for conductive ink with a low percolation threshold. The preparation method particularly comprises the following steps that silver nanowire dispersion liquid is mixed with non-conductive nano particle dispersion liquid, and silver nanowires and non-conductive nano particles are hybridized and assembled to form hybrids of the silver nanowires and the non-conductive nano particles; the hybrids are centrifuged, and supernatant liquid is discarded to obtain gelatinous hybrids of the silver nanowires and the non-conductive nano particles; the obtained hybrids are evenly mixed with macromolecular matrixes, and after the viscosity is regulated with solvent, the conductive ink with the low percolation threshold is obtained. The preparation method is simple and effective, solves the problem that at present, the silver nanowires are prone to agglomeration in the resin matrixes after the conductive ink is solidified and dried, and has a wide application prospect.

The invention provides a silver salt doped silver conductive adhesive, as well as a preparation method and application thereof. The silver salt doped silver conductive adhesive is prepared from the following raw materials in parts by weight: 0.01 to 5 parts of silver salt, 50 to 85 parts of micron silver powder, 10 to 50 parts of epoxy resin, 0.5 to 60 parts of a curing agent, 0.05 to 5 parts of an accelerator, 0.05 to 5 parts of a coupling agent, 1 to 10 parts of a diluent and 0.05 to 2 parts of an anti-precipitant. According to the preparation method, the silver salt is introduced into the formula of the silver conductive adhesive in a doping manner, so that the using amount of the silver powder can be reduced by 15 to 20 percent on the premise of ensuring the conductivity of the silver conductive adhesive; under the same addition of the silver powder, the electrical conductivity of the silver conductive adhesive is greatly improved, and moreover, the silver conductive adhesive has strong shear strength and high aging resistance; the prepared silver salt doped silver conductive adhesive can be widely applied to the fields of solar cell, IC (integrated circuit) and LED (light-emitting diode) packaging and the like.

The invention discloses a preparation method for a secondarily-silver-plated highly-conductive filling material. The preparation method comprises the following steps: 1) subjecting a substrate to ultrasonic dispersion in deionized water, successively adding tannic acid and a ferric trichloride solution, and carrying out uniform mixing under stirring so as to obtain a substrate surface-deposited with polytannic acid-ferric trichloride; 2) dissolving the obtained substrate in deionized water, adding a silver nitrate solution and ethylene glycol, and carrying out reducing with octylamine so as toobtain a substrate having silver nanoparticle on the surface after primary silver plating; 3) titrating a silver nitrate solution with ammonia until a precipitate just disappears so as to prepare a silver plating solution; 4) placing the substrate having the silver nanoparticle on the surface into the silver plating solution prepared in the step 3), adding a dispersant, and carrying out stirring;and 5) adding a reducing agent solution so as to obtain a substrate with silver layer covered surface. The preparation method provided by the invention is simple and convenient to operate, greatly shortens the time of modification, realizes uniform and compact silver plating, and prepares a composite material with excellent bonding stability and electrical conductivity.

The invention provides a preparation method of a conductive composite material and belongs to the field of material preparation. The preparation method is characterized by comprising the following steps: soaking graphene micro-flakes and an ultrahigh-molecular weight polyethylene powder in ethanol and performing ultrasonic dispersion by use of an ultrasonic cell smasher to form a uniformly distributed suspension; performing suction filtration and vacuum drying to remove the ethanol solvent, so that the graphene micro-flakes are evenly attached on the surface of the ultrahigh-molecular weight polyethylene particles; finally, performing compression molding on the obtained material, and then cooling to a room temperature under a constant pressure, thereby obtaining a raw material. The preparation process is improved, so that a more complete and stable effective conductive network structure can be formed inside the conductive composite material, and therefore, the percolation threshold of the material is greatly reduced, and the material has the maximum peak resistivity and relatively low room temperature resistivity. The preparation method of the conductive composite material is simple to operate, simple and convenient in process, and suitable for popularization and utilization in the related fields.

The present invention relates to a polyester/gypsum nano electrical conductive composite material and its preparation method, belonging to the field of electrical conductive composite material preparation technology. It is formed from main base body polyester, auxiliary base body and gypsum according to the mixing ratio of 100:5-60:2-40. Said invention has lower percolation threshold (3-4%), and when the gypsum content is 4%, its conductivity can be upto 10 to the pwer-6 s/cm.

The invention discloses a cyanate resin base composite material with a low percolation threshold and a high dielectric constant and a preparation method thereof. The cyanate resin base composite material is characterized by comprising the following components by volume: 10%-15% of calcium copper titanate, 0.5%-3.0% of expanded graphite sheets and 89.5%-82.0% of cyanate, wherein the granularity of the calcium copper titanate ranges from 1 micrometer to 2 micrometers; the diameters of the expanded graphite sheets are 10-50 micrometers, and radius-thickness ratio is between 300 and 500. The preparation method of the cyanate resin base composite material comprises the following steps of: mixing the calcium copper titanate, the expanded graphite sheets and the cyanate; and melting at 80-100 DEG C, then raising temperature to 120-150 DEG C, and pre-polymerizing until obvious sedimentation of the calcium copper titanate and the expanded graphite sheets exists. The invention can obviously enhance the dielectric constant of the cyanate resin base composite material by regulating the relative content of added components in the cyanate resin base composite material and utilizing synergistic effect generated among physically and chemically treated components, has the advantages of great low percolation threshold, low dielectric loss, good heat resistance, low cost, simple preparation method, and the like and has wide application prospect in the fields of electronic engineering, electrical engineering, and the like as a composite material with the high dielectric constant.