70 results about "Composite epoxy material" patented technology

The invention relates to the technical field of preparation of heat-conducting epoxy composite materials, in particular to a graphite / carbon fiber felt / epoxy composite material with a three-dimensional heat-conducting network, which is prepared by forming a graphite / carbon fiber felt three-dimensional heat-conducting network by graphite and a carbon fiber surfacing felt and then compounding the graphite / carbon fiber felt three-dimensional heat-conducting network with an epoxy resin matrix. The preparation method disclosed by the invention has the characteristics of simple and convenient process and easiness in operation mastering, and the obtained composite material shows good convenience in the aspect of processing and is relatively low in cost. Experimental results show that the in-plane heat conductivity of the prepared heat-conducting composite material can reach 0.763 W / mK, and compared with a pure epoxy resin matrix, the heat conductivity of the heat-conducting composite material is improved by about 302%, and the heat-conducting composite material shows excellent heat-conducting property.

The invention belongs to the technical field of high-voltage insulation, and particularly discloses an aramid fiber / epoxy composite material interface design and insulating property strengthening method and application, and the method comprises the following steps: carrying out direct fluorination pretreatment on the surface of aramid fiber cloth; soaking the aramid fiber cloth subjected to fluorination pretreatment in the aramid nanofiber solution; performing drying treatment; the modified aramid fiber cloth is laid and placed in a composite material forming mold, and the modified aramid fiber cloth is fully impregnated with epoxy resin and a curing agent based on a vacuum pressure impregnation technology and cured at a high temperature. According to the aramid fiber / epoxy composite material interface design and insulating property strengthening method and application, a micro-nano multi-scale interface is constructed through bridging of the micron-sized fluorinated layer and the nanofiber layer, the problem of insulating property improvement under the coupling effect of large mechanical stress and high electric field is solved in a breakthrough mode, the manufacturing process is simple, the cost is low, and the method is suitable for industrial production. And large-batch preparation can be realized, and a new thought is provided for insulation design of power equipment in the high-voltage insulation field.

The invention discloses a low-loss resin composition containing active ester, a prepreg and a copper-clad laminate, the resin composition comprises the following main components by weight: 30-70 parts of epoxy resin, 30-70 parts of an epoxy curing agent, 0-3 parts of a curing accelerator, and 20-100 parts of a filler; wherein the epoxy curing agent is tetraphenol fluorenyl active ester; the prepreg is prepared by dipping glass cloth in a glue solution formed by the low-loss resin composition and baking the glass cloth in an oven at 80-200 DEG C for 1-20 minutes after dipping is completed, the copper-clad plate is prepared from the prepreg, fluorine-containing tetrafunctional active ester is synthesized through esterification reaction of tetraphenol fluorene and pentafluorobenzoyl chloride, and the fluorine-containing tetrafunctional active ester is used for preparing the copper-clad plate. A rigid fluorene ring structure is introduced, so that the thermal performance of the cured epoxy composite material is favorably improved; therefore, the invention effectively solves the problems that the existing resin composition for preparing the copper-clad plate is insufficient in heat resistance, and in order to meet the requirement of low polarity, the dosage of the filler is increased, the interfacial compatibility of the resin and the filler becomes poor, and the dielectric loss is further improved.

A urea-formaldehyde microcapsule shell surface modification method beneficial to toughening of an epoxy composite material. The method comprises: uniformly mixing polyvinyl alcohol powder with deionized water to obtain a surfactant aqueous solution; mixing deionized water with the surfactant aqueous solution, then adding urea, ammonium chloride, and resorcinol, stirring the mixture, dropwise adding a diluted hydrochloric acid solution to adjust the pH, and stirring the mixture to obtain a stable emulsion; adding a formaldehyde-urea mixed solution to the stable emulsion and stirring and heating the mixture; after the heating reaction is completed, cooling the mixture to room temperature, and carrying out vacuum filtration, washing with deionized water, filtration, and then vacuum drying to obtain a urea-formaldehyde microcapsule shell; and mixing 3-aminopropyltriethoxysilane with deionized water, dropwise adding a diluted hydrochloric acid solution to adjust the pH to obtain a modified solution, adding the urea-formaldehyde microcapsule shell to the modified solution, stirring the mixture, and then carrying out vacuum filtration and drying to obtain a urea-formaldehyde microcapsule shell with the surface modified.

The invention provides a high-thermal-conductivity flexible epoxy composite material as well as a preparation method and application thereof, and belongs to the field of high polymer materials. The composite material disclosed by the invention is prepared by adding polydopamine modified BN and FG which are jointly used as fillers into an epoxy matrix and adopting polyether amine as a curing agent. The polydopamine modified BN and the FG are jointly used, so that a synergistic interaction effect can be achieved in the aspects of heat-conducting property, dielectric property and mechanical strength. The epoxy composite material disclosed by the invention can obtain excellent heat-conducting property, dielectric property and insulating property under the compatibility of specific raw materials. And when the curing agent with a long molecular chain is adopted, the epoxy composite material can obtain excellent flexibility, and the problem of brittleness of the existing epoxy composite material is solved. A research basis is provided for preparation and performance research of the flexible epoxy composite material, and the flexible epoxy composite material has a good application prospect.

The application belongs to the field of epoxy resin composites, and specifically provides a high-strength low-density epoxy SMC composite material and a preparation method thereof, which is prepared by the following steps: S01. Taking a PVC core plate, gluing after grooving, then laying a fiber cloth, vacuumizing under negative pressure after film covering, then pouring a pre-impregnation liquid, and placing to obtain a pre-cured composite plate; S02. Taking the pre-cured composite plate, placing overnight after mold pressing treatment, and then obtaining after demolding and edge trimming treatment; the pre-impregnation liquid preparation step comprises the following: mixing an active diluent, an accelerator, modified microspheres and a filler, first adding an epoxy resin, stirring, then adding the remaining amount of epoxy resin, and then adding a curing agent and a demolding agent, and continuously mixing to obtain the pre-impregnation liquid; the modified microspheres are used as a pre-impregnation liquid additive component, and the prepared SMC composite material product has a density ≤1.57 g / cm 3 , an impact strength ≥84.5 KJ / m 2 , and good flame retardance.

The application discloses a method for regulating the dynamic performance of hot-pressing molding epoxy vitrimer composites by the V-shaped content of oriented fillers, uses flake graphite as the lamellar oriented filler, and uses the dynamically chemically cross-linked epoxy vitrimer as the resin matrix, so that the content of the lamellar oriented filler is changed by changing the single-layer thickness and the number of layers while keeping the total thickness unchanged, and the V-shaped regulation method of the dynamic performance of the hot-pressing molding anisotropic epoxy vitrimer composites is realized. The dynamic performance of the epoxy vitrimer composite presents a V-shaped change trend with the content of the lamellar oriented filler, which is completely different from the linear inhibition behavior of conventional fillers, and the application can be used for regulating the dynamic performance of the epoxy vitrimer by the V-shaped content of the oriented filler.

The wind power blade epoxy fiber composite material and preparation method relate to material technology and environmental protection technology, and the preparation method comprises the following steps: (1) preparation of glycidyl ester type epoxy resin: after mixing, the low molecular weight glycidyl ester type epoxy resin is reacted with a chain extender modifier, and the low molecular weight glycidyl ester type epoxy resin molecules are combined into high molecular weight glycidyl ester type epoxy resin molecules; (2) preparation of an epoxy resin composition: the glycidyl ester type epoxy resin prepared in the step (1) is uniformly mixed with an amine curing agent at room temperature to obtain the epoxy resin composition; (3) the epoxy resin composition is impregnated into inorganic fibers, and after drying, the wind power blade epoxy composite material is obtained. The wind power blade material has good mechanical properties, high heat resistance, low production cost, and is easy to recycle.

The invention provides an epoxy-terminated polyurethane flexibilizer and a preparation method and application thereof, and belongs to the technical field of epoxy composites.The epoxy-terminated polyurethane flexibilizer is prepared from polyol, isocyanate, a chain extender, a catalyst, metal salt and epoxy resin, and the chain extender comprises hydroxybenzoxazine. The epoxy-terminated polyurethane toughening agent provided by the invention contains carbamate groups, benzoxazine groups and five-membered oxazolidinone structures, the groups have strong polarity, and due to the introduction of the five-membered oxazolidinone and the benzoxazine groups, the toughening agent has excellent stability at a high temperature and in a salt mist old chemical process, so that the toughness of the toughening agent is improved, and the service life of the toughening agent is prolonged. The toughening agent is added into the epoxy resin structural adhesive, the adhesion of the epoxy resin structural adhesive to metal materials can be improved while the glass transition temperature is not reduced, and the toughening agent further contains a polyether chain segment which can improve the low-temperature impact resistance of the epoxy resin structural adhesive.

This invention discloses a silk fibroin peptide-modified alumina filler, an epoxy resin composite material, and their preparation method. The preparation method of the epoxy resin composite material includes the following steps: S1: Preparation of silk fibroin peptide-modified alumina filler: Silk fibroin peptides are dispersed in water, and alumina filler is added to allow the silk fibroin peptides to be adsorbed onto the surface of the alumina filler; then, after solid-liquid separation and drying, silk fibroin peptide-modified alumina filler is obtained; S2: Preparation of epoxy resin composite material: The silk fibroin peptide-modified alumina filler is mixed evenly with epoxy resin and a curing agent, and then cured to obtain an epoxy resin composite material based on silk fibroin peptide-modified alumina. The epoxy resin composite material obtained utilizes biodegradable silk fibroin peptides to modify the surface of the alumina filler, constructing a three-dimensional thermally conductive network with low interfacial thermal resistance, thereby achieving synergistic optimization of the thermal conductivity and degradability of the epoxy composite material.

The invention provides a toughening curing agent and a preparation method thereof as well as an epoxy composite material and application thereof, and belongs to the technical field of composite materials. A long-chain modifier diamine compound with excellent flexibility and mechanical properties is adopted to modify an anhydride curing agent, amino groups of the diamine compound react with anhydride groups of the anhydride curing agent, the long-chain modifier with excellent mechanical properties is embedded into the curing agent, and the curing agent with a rigid-flexible-rigid structure is formed; the molecular chain segment length of the curing agent can be effectively increased, so that the free volume ratio of the molecular structure of the epoxy composite material is improved, the epoxy composite material can obtain a displacement space when subjected to mechanical stress, generation of internal stress is reduced, and reliable toughening of the epoxy composite material is realized; the anhydride curing agent can endow the epoxy composite material with excellent heat resistance and mechanical properties at high temperature.

The invention discloses a rear cover laminated board with improved bending performance and a preparation method thereof, relates to the technical field of electronic product shells, and provides the rear cover laminated board with improved bending performance and the preparation method thereof. The silicon carbide fiber is used as a base material, the tensile strength of the silicon carbide fiber is high, and excellent rigid support can be provided for the laminated board, so that the bending strength of the epoxy composite material is improved, and the performance requirement of a 3C shell is met. The modified epoxy resin is used as a matrix, the silicon carbide ceramic fiber cloth coated with dopamine is doped, and the cobalt hydroxide nanosheets are loaded on the silicon carbide ceramic fiber cloth, so that the strength of the laminated board is enhanced. Then, dopamine is used for coating, and a silicon dioxide aqueous solution is used for forming a silicon dioxide-containing micro-nano structure on the surface, so that the surface hydrophobicity is enhanced. The prepared shell material not only has enough rigidity, but also has excellent toughness, and meets the requirements of'deformation resistance 'and'fracture resistance'.

The invention relates to a flame-retardant recyclable plant fiber reinforced epoxy composite material and a preparation method thereof, and belongs to the technical field of flame retardance. The preparation method comprises the following steps: (1) carrying out a reaction on N, N, N ', N'-tetraepoxypropyl-4, 4 '-diaminodiphenylmethane (TGDDM) and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), so as to obtain an epoxy precursor DOPO-TGDDM, and carrying out a reaction on the epoxy precursor DOPO-TGDDM and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), so as to obtain an epoxy precursor DOPO-TGDDM; and (2) carrying out hot pressing curing on the DOPO-TGDDM and an anhydride curing agent, so as to prepare the polyester type epoxy glass polymer (vitrimer) pre-cured sheet. And (3) alternately stacking the epoxy vitrimer pre-cured sheets and plant fiber cloth, putting the stacked epoxy vitrimer pre-cured sheets and the plant fiber cloth into a hot press, and carrying out hot pressing to obtain the plant fiber reinforced epoxy composite material. The prepared plant fiber reinforced epoxy composite material has excellent intrinsic flame retardance, smoke suppression performance and degradability and recoverability.

The application relates to a double-P flame retardant, an epoxy composite material and application in a type IV hydrogen storage cylinder, relates to the technical field of flame retardant materials, and solves the problem that the existing epoxy resin used in the type IV hydrogen storage cylinder cannot simultaneously consider strength, toughness and flame retardant characteristics.The double-P flame retardant is synthesized by the following steps: reacting green and environment-friendly renewable bio-based raw material vanillin with a catalyst triethylamine to obtain a first-step intermediate, then reacting the first-step intermediate with a biomass amine substance to obtain a Schiff base intermediate, and finally reacting the Schiff base intermediate with DOPO.The epoxy composite material is prepared by the flame retardant and the epoxy resin.The reaction process is convenient to operate, and the preparation method is simple, which not only provides a new idea for expanding the application of the epoxy resin in the field of high-performance materials, but also provides a relatively suitable winding layer material for hydrogen energy, especially the type IV hydrogen storage cylinder, and is suitable for industrial production.

The invention relates to a method for improving the mechanical property of epoxy resin based on metamaterial skeleton support, the mechanical property of the epoxy resin is improved by designing a honeycomb metamaterial skeleton, and the specific steps are as follows: S1, designing a skeleton structure: selecting a honeycomb shape of the honeycomb metamaterial skeleton, and regulating and controlling the geometric dimension and wall thickness parameters of the honeycomb shape; and S2, preparing metamaterial skeleton composite resin: printing and curing dual-curing epoxy resin by adopting a photocuring 3D printing technology to obtain a honeycomb metamaterial skeleton as a support, pouring thermocuring epoxy resin into gaps of the honeycomb metamaterial skeleton, and performing vacuum drying after curing to obtain the metamaterial skeleton composite resin. A photo-curing 3D printing metamaterial framework is adopted as a support, thermosetting epoxy resin is poured in gaps of the framework, and the metamaterial framework realizes directional optimization of a stress transfer path of the material by accurately regulating and controlling unit cell shapes, geometric dimensions, wall thickness parameters and the like, so that the mechanical property of the epoxy composite material is improved.

The invention relates to the technical field of aircrafts, in particular to a composite material rudder wing structure for an aircraft and a preparation method thereof.The composite material rudder wing structure comprises a main beam and sandwich foam layers located on the two sides of the main beam, the main beam and the sandwich foam layers are of a structure with the middle thick and the two ends thin, and the main beam and the sandwich foam layers are connected through an adhesive; the main beam comprises at least three high-modulus glass fiber pultrusion plates, multi-axial glass fiber prepreg is arranged between the adjacent high-modulus glass fiber pultrusion plates, and the main beam and the sandwich foam layer are coated with a glass fiber-epoxy composite material layer. The rudder wing structure has the advantage of being light in weight, and the weight of the rudder wing structure can be reduced by 35%-40% compared with that of an aluminum alloy rudder wing; the rudder wing is made of a glass fiber composite material and has good wave-transparent performance, the surface of the rudder wing is subjected to appearance treatment through fluorocarbon paint, and the requirements for corrosion resistance, aging resistance and wave-transparent related performance are improved.

The invention relates to the technical field of gas insulation, in particular to an epoxy composite material internal crack defect detection method, equipment and a medium, structural parameters of a 110kV epoxy basin-type insulator are measured, and three-dimensional modeling software is adopted to construct a three-dimensional structural model equal to a real object in proportion; applying a thermal boundary condition to the three-dimensional structure model body, respectively setting the depth and the deflection angle of the crack defect as h and theta, and setting the material attribute of the bubble defect area as air; the method comprises the following steps: acquiring surface thermal imaging characteristics of the defect of the epoxy basin-type insulator based on a solid heat transfer theory, outputting the surface thermal imaging characteristics of the defect of the epoxy basin-type insulator, and acquiring surface thermal imaging characteristics of the crack defect at different deflection angles under different defect depths by changing the depth and the deflection angle of the crack defect for many times based on the solid heat transfer theory. Equipment temperature resolution is used as a judgment basis, and feasibility exploration of crack defect detection at different deflection angles under different defect depths is realized.

The invention belongs to the field of functional polymers, and particularly relates to a high-toughness, repairable, recoverable and flame-retardant epoxy vitrimer and a composite material thereof. The epoxy vitrimer is obtained by reacting dithio-diphenyl diglycidyl ether, bisphenol A diglycidyl ether, isocyanuric acid tri [2-(3-mercaptopropionyloxy) ethyl ester] and dithio-diphenyl diphosphate diphenyl at the temperature ranging from room temperature to 90 DEG C or above, after being completely cured, the epoxy vitrimer shows the characteristic of high toughness, the elongation at break reaches 200% or above, and the epoxy vitrimer shows that damage can be repaired and the service life of the epoxy vitrimer is prolonged. And hot-pressing recycling and reshaping and flame-retardant characteristics can be realized. The high-toughness, repairable, recoverable and flame-retardant epoxy vitrimer composite material is obtained by reacting the epoxy vitrimer resin and silicon dioxide modified by dithio diphenyl phosphate diphenyl glycidyl ether at the temperature ranging from the room temperature to 90 DEG C or above; the epoxy vitrimer composite material shows the characteristic of high toughness after being completely cured, the elongation at break reaches 150% or above, and the epoxy vitrimer composite material shows the characteristics of being repairable in damage, capable of being recycled and reformed through hot pressing and flame-retardant.

The invention relates to the technical field of flame retardants, in particular to a P / N synergistic flame retardant, a preparation method thereof and application of the P / N synergistic flame retardant in epoxy resin. A conventional flame retardant is complex in structure, poor in compatibility with epoxy resin and large in influence on the performance of the epoxy resin. In order to solve the problems, the flame retardant is synthesized through a two-step method, firstly, 5-aminotetrazole and benzaldehyde or a derivative thereof react to generate a Schiff base intermediate, and then the intermediate and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are subjected to a phosphorus-hydrogen addition reaction to obtain a final product. The limit oxygen index of the composite material can be increased to 35.8% by only adding 4wt% of the composite material into epoxy resin, the vertical combustion grade reaches UL-94 V-0 grade, and meanwhile, the influence on the original high transparency and mechanical property of the material is extremely small. The invention provides a new technical scheme for preparing the high-performance environment-friendly flame-retardant epoxy composite material.

The invention belongs to the technical field of preparation of carbon fiber heat-conducting composite materials, and discloses a carbon fiber / phenolic aldehyde / epoxy composite material with a three-dimensional heat-conducting network, which comprises a three-dimensional skeleton structure formed by hot-pressing and curing carbon fibers and phenolic resin, and the epoxy resin is subjected to vacuum impregnation, is filled in gaps of the three-dimensional skeleton structure and is subjected to hot-pressing curing. The preparation method comprises the steps of ultrasonic dispersion, vacuum filtration, hot press molding and vacuum infusion. The continuous three-dimensional carbon fiber network is constructed as a main heat conduction path, so that the heat conduction capability of the composite material is remarkably improved; experimental data show that by adjusting the content of the carbon fibers, the in-plane heat conductivity of the composite material can be increased to 56.19 W / (m.K), the out-plane heat conductivity can also be increased to 6.72 W / (m.K), excellent anisotropic heat conduction characteristics are shown, and heat dissipation requirements in different directions can be met in a targeted mode.

The invention discloses a high-thermal-conductivity epoxy composite material efficiently induced and oriented by a high-frequency high-voltage bipolar square wave electric field and a preparation method of the high-thermal-conductivity epoxy composite material. An epoxy resin mixed solution doped with hexagonal boron nitride is subjected to defoaming, pouring and curing. During curing, high-frequency square-wave voltage is applied for electric field orientation induction, and then the curing procedure is continued, so that the epoxy resin composite material is completely cured. The waveform distortion problem caused by the dielectric constant of liquid epoxy under low frequency is fully considered, the spatial orientation of hexagonal boron nitride (h-BN) is accurately regulated and controlled by adopting the dynamic polarization effect of the high-frequency and high-voltage bipolar square wave electric field, a through continuous heat conduction network is formed, the transfer path of heat in the specific direction is optimized, and the heat conduction efficiency is improved. The scattering of phonons at an interface is effectively reduced, so that the heat-conducting property of the epoxy composite material is greatly improved. By optimizing the synergism of the high-frequency high-voltage bipolar square wave electric field intensity and the boron nitride doping amount, the balance of heat conduction, insulation and mechanical properties is realized under the condition of low filling amount.

The invention belongs to the field of epoxy resin composite materials, and particularly provides a high-strength low-density epoxy SMC composite material and a preparation method thereof.The preparation method comprises the following steps that S01, a PVC core plate is taken, grooving is conducted, then glue brushing is conducted, then fiber cloth is laid, film covering is conducted, negative pressure vacuumizing is conducted, then presoaking liquid is poured, and standing is conducted to obtain a precured composite plate; and S02, taking the pre-cured composite board, carrying out mold pressing treatment, standing overnight, and carrying out demolding and trimming treatment, so as to obtain the composite board. The preparation method of the prepreg liquid comprises the following steps: mixing a reactive diluent, an accelerant, modified microspheres and a filler, adding epoxy resin for the first time, stirring, supplementing the balance of epoxy resin, adding a curing agent and a release agent, and continuously mixing to obtain the prepreg liquid; the SMC composite material product prepared by using the modified microspheres as a preimpregnation liquid adding component has the density of less than or equal to 1.57 g / cm < 3 >, the impact strength of more than or equal to 84.5 KJ / m < 2 > and good flame retardance.

The invention discloses a DLC (Diamond Like Carbon) coated Al2O3 epoxy composite material, a thermal conductivity improving method of the DLC coated Al2O3 epoxy composite material, DLC modified Al2O3 core-shell particles as well as a preparation method and application of the DLC modified Al2O3 core-shell particles. The DLC coated Al2O3 epoxy composite material comprises an epoxy resin matrix and a DLC modified Al2O3 core-shell particle filler, according to the DLC modified Al2O3 core-shell particle, Al2O3 serves as an inner core, DLC serves as a shell layer, and the sphybridization rate of the DLC shell layer is not smaller than 55%; the phonon matching degree between the epoxy resin and the filler can be effectively improved, the interface thermal resistance is reduced, and then the thermal conductivity of the epoxy composite material is improved.

The invention provides an epoxy composite material capable of being repaired and reprocessed under the condition of being lower than the glass-transition temperature as well as a preparation method and application of the epoxy composite material, and belongs to the field of advanced materials. Epoxy resin containing imine bonds and VU dynamic covalent bonds is used as a matrix, and the molded composite material is prepared through continuous fiber reinforcement. The composite material has good initial interlaminar shear strength and repairing capacity, hot-pressing repairing can be carried out under the condition that the temperature is lower than the glass-transition temperature, and the fibers of the composite material can be recycled in a lossless mode. The composite material prepared by the invention shows remarkable advantages in the aspects of composite material repairing, service life prolonging, secondary processing, recycling, reprocessing, recycling, resource saving, environmental protection and the like, and has huge potential and wide application prospects in the field of composite materials.

The present invention relates to a flame-retardant recyclable plant fiber-reinforced epoxy composite material and a preparation method thereof, belonging to the field of flame-retardant technology. The preparation method comprises the following steps: (1) reacting N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM) with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to obtain an epoxy precursor DOPO-TGDDM; (2) subjecting DOPO-TGDDM and an acid anhydride curing agent to hot pressing and curing to obtain a polyester-type epoxy-based glassy polymer (vitrimer) pre-cured sheet. (3) Alternately stacking the epoxy vitrimer pre-cured sheet and the plant fiber cloth, and putting them into a hot press to hot press to obtain a plant fiber-reinforced epoxy composite material. The prepared plant fiber-reinforced epoxy composite material has excellent intrinsic flame retardancy, smoke suppression property and degradability and recyclability.

This invention belongs to the field of composite material technology, specifically relating to an epoxy composite material based on hollow glass microspheres as filler and its preparation method. Addressing the challenges of high surface polarity of hollow glass microspheres, poor compatibility with organic resins, and the difficulty of achieving a balance of high strength, high toughness, and aging resistance in existing composite materials, this invention utilizes ultraviolet ozone to synergistically activate glass microspheres, followed by surface modification with tannic acid. Simultaneously, a base epoxy resin, octaepoxypropyl cage-type polysilsesquioxane, and bis(2-aminophenyl)disulfide are mixed. Finally, tannic acid-modified glass microspheres and a curing agent are added to the prepolymer, followed by stepwise temperature curing to obtain the epoxy composite material.

The present invention relates to the technical field of epoxy resins, and provides a flame-retardant epoxy resin composition and a preparation method therefor, prepreg and a composite material. The flame-retardant epoxy resin composition comprises an epoxy resin, a halogen-free flame retardant, and an epoxy resin curing agent; the weight of the epoxy resin accounts for 55-70% of the weight of the flame-retardant epoxy resin composition, the weight of the halogen-free flame retardant accounts for 25-36% of the weight of the flame-retardant epoxy resin composition, the gel time of the flame-retardant epoxy resin composition at 150°C is less than or equal to 150 sec, and the glass transition temperature of the cured flame-retardant epoxy resin composition is greater than or equal to 120°C. The present invention solves the problems of large flame retardant addition proportion, lower curing speed, reduction of the heat resistance Tg of a resin, and significant reduction of the mechanical properties of an epoxy composite material when existing flame-retardant epoxy resin compositions have excellent flame-retardant properties.

This invention relates to a planar impact low-bursting-force directional fracture membrane cap and its preparation method. The membrane cap comprises a membrane cap body (1), a stress concentration structure (2), and a sub-cap connecting structure (4). The membrane cap body (1) is a glass fiber epoxy composite material structure, and the membrane cap body (1) further includes a connecting flange (101), a reinforcement (102), a fracture sub-cap (103), and a weakening groove (104). This invention achieves the controllability of the fragments after the fracture of a membrane cap subjected to surface-to-surface impact, overcomes the uncontrollability of the fragments after the fracture of a membrane cap subjected to surface-to-surface impact in the prior art, and protects the integrity of the impact without damage.

This invention belongs to the field of thermosetting polymer composite material preparation technology, and particularly to graphene-reinforced high-density epoxy composite materials for casting molding and their preparation method. The method uses a two-component epoxy resin system as the continuous phase and graphene as both a functional filler and a reinforcing filler. First, component A and component B are premixed in a specific ratio. Then, graphene is added stepwise and mixed at low speed. Subsequently, a vacuum degassing process is performed, followed by preheating the mold for casting, a second vacuuming process, and step-curing at 80℃ / 140℃. The graphene is preferably one of high-purity multilayer graphene, few-layer graphene, or single-layer graphene, and the addition process can be carried out in two, three, or four steps depending on the number of layers and the difference in bulk density. This method can balance the uniformity of graphene dispersion, slurry workability, product density, and consistent black surface appearance. The resulting products are suitable for electronic packaging, potting compounds, functional structural components, and thermally and electrically conductive castings.