32results about How to "Enhanced interfacial polarization" patented technology

The invention provides a polyimide high-temperature dielectric composite film and a preparation method thereof. The composite film is formed by blending at least one of hexagonal boron nitride nanosheet and molybdenum disulfide nanosheet as well as polyimide. The mass fraction of the hexagonal boron nitride nanosheet is 6% to 12%, and the mass fraction of the molybdenum disulfide nanosheet is 1% to 2%. The introduction of a nanosheet filler not only improves the thermal properties of a polyimide film, but also improves the high temperature dielectric properties that a conventional PI film hasnot been involved. The composite film has the advantages of low dielectric loss, high breakdown strength, energy storage density and energy storage efficiency at normal temperature, and keeps low conductance loss and high breakdown field strength and energy storage density at the temperature of 150 DEG C.

The invention discloses a preparation method of a graphene oxide-polyaniline composite electromagnetic shielding material. The method comprises the steps that ultrasonic dispersion is performed on graphene oxide in an aqueous perchloric acid solution, aniline is added, and the mixture is mixed evenly under magnetic stirring to obtain a first solution; ammonium persulfate is put into the aqueous perchloric acid solution, and ultrasonic dispersion is performed to obtain a second solution; the second solution is added in the first solution, continuous stirring and reacting are performed in an ice bath for 24 h to obtain a dispersing solution of a product, the dispersing solution is sequentially washed with deionized water, ethyl alcohol and acetone until the pH value is 6-7, filtering and drying are performed, and then the graphene oxide-polyaniline composite electromagnetic shielding material is obtained. According to the preparation method of the graphene oxide-polyaniline composite electromagnetic shielding material, a layer of directional polyaniline nanorods grow on the surface of the graphene oxide, the electric conductivity of the graphene oxide is improved through the conductive property of the polyaniline, interfacial polarization of contact layer faces of the graphene oxide and polyaniline is improved, and therefore the good electromagnetic wave shielding effectiveness is achieved; the technological processes are simple, the raw materials are easy to obtain, and application and popularization are easy.

The invention relates to a heating modified MXene/ferroferric oxide composite wave-absorbing material and a preparation method thereof. Magnetic ferroferric oxide particles (Fe3O4) are grown in situ on the surface of a two-dimensional material MXene (Ti3C2Tx), and the MXene is heated in a tubular furnace to be partially oxidized into titanium dioxide (TiO2) to finally obtain the layered compositematerial. MXene and TiO2 are dielectric loss wave-absorbing materials, and Fe3O4 is a magnetic loss wave-absorbing material, so that the obtained composite material can synergistically absorb electromagnetic waves through dielectric loss and magnetic loss mechanisms, and the wave-absorbing effect is enhanced. Meanwhile, the composite material has a layered structure, so that electromagnetic wavescan be subjected to multiple interlayer reflection in the composite material and are more easily absorbed by the composite material. And finally, the impedance matching of MXene is improved by Fe3O4 and TiO2, the interfacial polarization of the composite material is enhanced by the multi-component structure, and the wave absorbing effect of the composite material is further enhanced.

The invention discloses a multi-phase high-dielectric-constant composite material with an isolation structure and a preparation method thereof. The material is prepared from, by mass, 0-10 parts of conducting packing, 10-50 parts of thermoplastic resin, 0-1 parts of an accelerant, 0-20 parts of a modifying agent, 0-20 parts of isolation balls, 50-100 parts of a curing agent and 100 parts of epoxy resin. By virtue of a suitable solvent and by means of a solution blending method, the modifying agent, the conducting packing, the thermoplastic resin and the epoxy resin are mixed to be uniform, the curing agent is added, the materials are mixed to be uniform, the mixture is poured into a mold and smeared into an electrode plate, heating is conducted for curing, and then the high-dielectric-constant multipolymer-based composite material with the isolation structure can be obtained. The block-shaped and film-shaped composite material can achieve the high dielectric constant and the low dielectric loss when the content of the conducting packing is low, is simple in preparation technology, easy to mold and process and short in molding period and has a very wide application prospect in the micro-electronics field and the motor and cable industries.

The invention relates to the technical field of EP dielectric material synthesis, and discloses a preparation method of a POSS-CuPc-SiO2 modified epoxy resin composite material, which comprises the following steps: carrying out Michael addition reaction on a phenyl functional group of a PDA-SiO2 hybrid monomer and an amino functional group of amino copper phthalocyanine (NH2-CuPc) to obtain a polyaminated CuPc-SiO2 hybrid dielectric monomer; the preparation method comprises the following steps: carrying out substitution reaction on an amino functional group of a multi-aminated CuPc-SiO2 hybrid dielectric monomer and a chlorine functional group of a monofunctional group 3-chloropropyl POSS to obtain a POSS-CuPc-SiO2 hybrid dielectric monomer; a POSS-CuPc-SiO2 hybrid dielectric monomer is used as a filler, E51 epoxy resin is used as a polymer matrix, and the POSS-CuPc-SiO2 modified epoxy resin composite material with high dielectric constant and low dielectric loss is prepared.

The invention relates to the technical field of high polymer compound materials, in particular to a compound material with high energy density and a preparation method thereof. The compound material with high energy density is mainly obtained by mixing titanate particles of a core-shell structure with a high polymer; the titanate particles of the core-shell structure is obtained by coating silicondioxide on the surface of the titanate particles. According to the compound material with the high energy density and the preparation method thereof, the silicon dioxide serving as an insulating layer is coated on the surface of ultra-fine barium titanate particles to form the titanate of the core-shell structure, the local electric field concentration and electric charge accumulation can be effectively weakened, the formation of a leakage current passage is prevented, the dielectric loss is reduced, the voltage resistant performance of the material is wholly improved, and the homogeneous dispersion of titanate and high-interface compatibility brought by a silicon dioxide layer can improve the puncture of thin film; the titanate of the core-shell structure compounds with the high polymer,and the compound material with excellent energy storage performance can be obtained under the condition of lower filling quantity.

The invention discloses a silver-titanium dioxide filler doped polyvinylidene fluoride dielectric composite film and a preparation method thereof, and is characterized in that the composite film is compounded by filling a polyvinylidene fluoride matrix with a silver-titanium dioxide filler, and the silver-titanium dioxide filler is of a core-shell structure, wherein a core layer is a bark-shaped one-dimensional titanium dioxide nanowire with the surface coated with flaky titanium dioxide, a shell layer is silver nanoparticles modified on the surface of the flaky titanium dioxide, and the preparation method comprises the following steps: dispersing the prepared silver-titanium dioxide filler in an organic solvent N-N dimethylformamide, then performing ultrasonic stirring, adding polyvinylidene fluoride, stirring, and preparing a dielectric composite film of the silver-titanium dioxide filler doped with polyvinylidene fluoride by adopting a solution casting method, wherein the volume fraction of the silver-titanium dioxide filler is 0.5-2%. The material has the advantages of extremely high polarization, relatively high charging and discharging efficiency and extremely high energy density under relatively low electric field intensity.

The invention discloses a porous Co3O4/Al2SiO5 low-density wave-absorbing-type composite-phase ceramic and a preparation method thereof. Particles of a Co3O4 wave-absorbing agent in the composite-phase ceramic are evenly dispersed in an Al2SiO5 ceramic fiberboard, which helps to improve the wave-absorbing performance of the material; the Co3O4 wave-absorbing agent in the composite ceramic has dielectric loss and magnetic loss on an electromagnetic wave; a layer of Co simple substance interface layer wraps the surface of each Co3O4 particle. The composite-phase ceramic material is low in density and good in high temperature resistance. According to the preparation method, a dipping method is adopted for introducing the wave-absorbing agent raw material into the porous ceramic, and the wave-absorbing agent in the obtained Co3O4/Al2SiO5 composite-phase ceramic can be evenly dispersed, which helps to improve the wave-absorbing performance of the material; the selected porous Al2SiO5 ceramic fiberboard is used as a base material and has the advantages of being resistant to high temperature and low in density, in the preparation process, the shape and size of the Al2SiO5 ceramic fiberboard are not changed, and the composite-phase ceramic keeps low density; according to the method, the whole preparation technology is simple in step, short in period, easy to operate and good in repeatability.

The invention provides a preparation method of a copper and ceramic powder composite electromagnetic shielding material. The method comprises the steps that S1 an L-cysteine solution is prepared; S2 L-cysteine-coated CuS particles are prepared; S3 tartaric acid modified barium titanate is prepared; S4 components comprises, by weight, 60 to 75 parts of acrylic resin, 3 to 8 parts of 2,2,4-trimethy-l,3 pentanediol monoisobutyrate, 0.2 to 0.5 part of nonylphenol epoxy vinyl ether, 10 to 20 parts of ethyl acetate, 10 to 20 parts of xylene, 40 to 50 parts of L-cysteine-coated CuS particles and 35 to 45 parts of tartrate-modified barium titanate are weighed; and S5 the components are mixed, ball-milled in a ball-milling tank to prepare a electromagnetic shielding coating. The electromagnetic shielding material prepared by the method has the advantages of high shielding efficiency and good electrical conductivity.

The invention discloses a microcellular foaming HIPS electromagnetic shielding material and a preparation method and application thereof, and belongs to the technical field of preparation of functional polymer materials. The electromagnetic shielding material is prepared by the following steps: carrying out melt blending on HIPS, a foaming agent and a cross-linking agent to prepare a blend I; subjecting HIPS, a compatilizer, an electromagnetic shielding aid, an antioxidant, an activating agent, a nucleating agent and a lubricating agent to melt blending to prepare a blend II, and finally, mixing the blend I and the blend II and subjecting a product to microcellular foaming to prepare the material. The microcellular foaming HIPS electromagnetic shielding material prepared by the invention has high electromagnetic shielding effectiveness and excellent electromagnetic shielding effectiveness stability, can be widely applied to linings of shells of electric appliances such as household appliances, medical electric appliances, outdoor electric appliances, industrial and mining electric appliances and the like, and has relatively high economic value and social benefit. And the method plays a key role in a forced authentication requirement of each export country.

The invention relates to a BaFe12O19 composite powder and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing BaFe12O19/CaFe2O4 composite powder and nano cobalt ferrite powder, carrying out heat treatment at 480-550 DEG C for 3-5 hours to obtain powder, wherein x is 0.6-0.9; dissolving the powder in a hydrochloric acid solution, stirring uniformly, and adding aniline; and adding an ammonium persulfate hydrochloric acid solution under ice water bath conditions, and reacting for 10-15 hours. As the CoFe2O4 content increases, the interface of the composite powder increases; and meanwhile, the synergistic effect among different materials can enhance the doublet and interfacial polarization, so that the dielectric loss is enhanced, and the impedance matching characteristic is enhanced, thereby achieving the goal of optimizing the wave-absorbing property. The composite powder has excellent wave-absorbing property; the reflection loss can reach -23 to -38dB; and the preparation technique of the composite powder is simple.

The invention relates to the technical field of high dielectric PS material synthesis, and discloses a preparation method of a POSS-copper phthalocyanine dielectric monomer modified polystyrene material, and the preparation method comprises the following steps: carrying out substitution elimination reaction on an amino functional group of amino copper phthalocyanine (NH2-CuPc) and a chloromethyl functional group of 4-chloromethyl styrene to obtain an octaaryl alkenyl copper phthalocyanine monomer; the preparation method comprises the following steps: carrying out hydrosilylation reaction on an aryl alkenyl functional group of an octaaryl alkenyl copper phthalocyanine monomer and a silicon hydrogen functional group of hydrogen-containing heptaphenyl cage-shaped silsesquioxane (POSS-H) to obtain a POSS-copper phthalocyanine dielectric monomer; the POSS-copper phthalocyanine dielectric monomer modified polystyrene material with high dielectric constant and low dielectric loss is prepared by taking a POSS-copper phthalocyanine dielectric monomer as a filler and polystyrene as a polymer matrix.

The invention discloses a metal-carbon composite particle and a preparation method and application thereof. The preparation method of the metal-carbon composite particles comprises the following steps: 1) dispersing cobalt salt or/and nickel salt and trimesic acid in a solvent, and reacting to obtain cobalt or/and nickel-based MOF (Metal Organic Framework); and 2) calcining the cobalt or/and nickel-based MOF in a protective atmosphere to obtain the metal-carbon composite particles. The metal-carbon composite particle has the advantages of excellent microwave absorption performance, wide absorption bandwidth, good impedance matching performance, light weight and simple preparation method, can be used in electromagnetic wave absorption materials, and has a very wide application prospect.

The invention discloses a layered double magnetic metal hydroxide derived magnetic metal and carbon composite wave-absorbing material and a preparation method thereof, the layered double magnetic metal hydroxide (LDH) is used as a precursor, and the magnetic metal and carbon composite wave-absorbing material with a multi-dimensional, multi-level and porous structure is synthesized through subsequent heat treatment. The preparation method is simple in process and low in cost, large-scale industrial production can be achieved, and the prepared composite wave-absorbing material is small in density, small in thickness, wide in effective absorption frequency band and high in reflection loss.

The invention relates to the technical field of preparation of polyimide thin films, in particular to a preparation process of an anti-curling polyimide thin film. The preparation process comprises the following steps: preparation of calcium molybdate nanopowder, preparation of modified nanopowder, synthesis of polymer resin, resin regulation and film formation. The surfaces of calcium molybdate nanoparticles are modified through KH550, the nanoparticles are prevented from being agglomerated in the polymer resin through volume steric hindrance of a long chain organic part, meanwhile, the compatibility between inorganic nanoparticle calcium molybdate and an organic polymer is also improved, and thus the nanoparticles are more evenly dispersed in a polyimide substrate; and a continuous and complete three-dimensional network is formed in the KH550-CaMoO4 nanoparticle polyimide substrate, thus the rigidity of polymer molecular chains is enhanced, acting force between the molecular chains is enhanced, energy needed for bending and cracking of the polymer molecular chains at the high temperature is increased, and the prepared thin film is good in anti-curling performance.