A composite aerogel-reinforced epoxy resin material and its preparation method and application

Abstract

The embodiments of the present invention relate to the technical field of composite materials, and specifically disclose a composite aerogel-reinforced epoxy resin material, its preparation method, and application. The composite aerogel-reinforced epoxy resin material comprises the following raw materials: composite aerogel, epoxy resin component A, and a silane coupling agent. The embodiments of the present invention use a composite aerogel prepared using a graphene oxide aqueous dispersion and a sodium alginate aqueous solution as an additive, and use a silane coupling agent to generate hydrogen bonds and crosslinking between the active groups on the surface of the graphene oxide and the sodium alginate, coupling agent, and epoxy resin, thereby effectively improving the tensile strength and shear strength of the material. This solves the problem of reduced tensile strength and shear strength in the prior art when preparing epoxy resin composite materials by adding graphene oxide and sodium alginate. Moreover, the preparation method provided by the embodiments of the present invention is simple and has broad market prospects.

Description

Technical Field

[0001] The embodiments of the present invention belong to the technical field of composite materials, and specifically relate to a composite aerogel-reinforced epoxy resin material, a preparation method thereof, and an application thereof. Background Art

[0002] With the continuous development of materials technology, epoxy resin, a commonly used polymer material, has been widely used in the chemical industry, aviation, and aerospace fields due to its excellent physical properties and chemical stability. Aerogel, also known as xerogel, is a lightweight nanoporous material with broad application prospects. This refers to a gel in which most of the solvent has been removed, leaving less liquid in the gel, or the medium filling the gel's spatial network is gas, while the surface is solid. It is characterized by low density, high specific surface area, high porosity, and a nanostructure. Graphene, a two-dimensional sheet material with a honeycomb lattice structure, not only has excellent conductivity, stability, and a high specific surface area, but also possesses excellent flexibility and mechanical strength. Although graphene oxide has a similar structure to graphene, its presence of polar groups such as epoxy, carboxyl, and hydroxyl groups gives it new properties such as enhanced dispersibility, compatibility, hydrophilicity, and ease of surface modification. Sodium alginate, a biomass polysaccharide material, has excellent biocompatibility and biodegradability, and is easily prepared into a gel material, which also has many applications in the hospital field.

[0003] Currently on the market, it is usually possible to significantly improve the thermal insulation performance, mechanical properties and durability of epoxy resin by adding aerogel to it, so as to meet the needs of more application scenarios. For example, in the prior art, graphene oxide aerogel is prepared by the sol-gel method, and then a low-viscosity epoxy resin is added to the formed aerogel to prepare an epoxy resin composite material with graphene oxide as the skeleton, which effectively improves the storage modulus. Although epoxy resin composite materials can be prepared using graphene oxide, sodium alginate, etc. as additives, most of them use graphene oxide or sodium alginate alone as raw materials and are prepared using aerogel technology. Moreover, when preparing composite materials by adding graphene oxide, sodium alginate, etc. to epoxy resin, there is often a problem of reduced tensile strength and / or shear strength due to the reduced degree of crosslinking between the additive and the epoxy resin. Therefore, the above-mentioned prior art solutions have the following defects: when preparing epoxy resin composite materials by adding graphene oxide and sodium alginate in the prior art, there is a problem of reduced tensile strength and shear strength. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a composite aerogel-reinforced epoxy resin material to solve the problem of reduced tensile strength and shear strength when preparing epoxy resin composite materials by adding graphene oxide and sodium alginate in the prior art mentioned in the background art.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A composite aerogel reinforced epoxy resin material comprises the following raw materials: composite aerogel, epoxy resin component A, and a silane coupling agent; wherein the composite aerogel is prepared using graphene oxide aqueous dispersion and sodium alginate aqueous solution as raw materials.

[0007] Preferably, in the composite aerogel, the mass content of graphene oxide is 30%-90%.

[0008] Further preferably, the composite aerogel is prepared by freeze-drying and post-crosslinking with calcium chloride using a graphene oxide aqueous dispersion and a sodium alginate aqueous solution as raw materials.

[0009] Still further preferably, the epoxy resin component A comprises the following raw materials in parts by weight: 2-20 parts by weight of epoxy resin component; 1-10 parts by weight of curing agent; 60-90 parts by weight of conductive filler; and 0-2.5 parts by weight of defoaming agent.

[0010] Another object of the present invention is to provide a method for preparing a composite aerogel-reinforced epoxy resin material, the method comprising the following steps:

[0011] An appropriate amount of composite aerogel and epoxy resin component A are weighed and placed in a container, and then a silane coupling agent is added and mixed evenly. The mixture is then placed in a mold and baked at 180-220° C. for 1-3 hours to obtain the composite aerogel reinforced epoxy resin material.

[0012] Another object of an embodiment of the present invention is to provide a use of the above-mentioned composite aerogel-reinforced epoxy resin material in preparing a composite material.

[0013] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0014] The composite aerogel-reinforced epoxy resin material provided by the embodiment of the present invention uses composite aerogel, epoxy resin component A, and silane coupling agent in a reasonable manner. The composite aerogel prepared from a graphene oxide aqueous dispersion and a sodium alginate aqueous solution as raw materials is used as an additive, and in combination with the action of the silane coupling agent, hydrogen bonds and cross-linking reactions can be generated between the active groups on the surface of the graphene oxide and the sodium alginate, silane coupling agent, and epoxy resin, thereby improving the tensile strength and shear strength of the epoxy resin. This solves the problem of reduced tensile strength and shear strength when preparing epoxy resin composite materials by adding graphene oxide and sodium alginate in the prior art. Moreover, the preparation method of the composite aerogel-reinforced epoxy resin material provided by the embodiment of the present invention is simple and can be used to prepare other types of resin-based composite materials, thus having broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention.

[0016] Figure 1 Infrared spectra of different composite aerogel samples provided in one embodiment of the present invention.

[0017] Figure 2 This is a scanning electron microscope image of different composite aerogel-reinforced epoxy resin materials provided by another embodiment of the present invention.

[0018] Figure 3 This is a scanning electron microscope image of GO / SA-1 / epoxy resin component A provided by another embodiment of the present invention.

[0019] Figure 4 This is a scanning electron microscope image of GO / SA-2 / epoxy resin component A provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the following embodiments will help those skilled in the art to further understand the embodiments of the present invention, but do not limit the embodiments of the present invention in any form. It should be pointed out that for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the embodiments of the present invention. These all fall within the scope of protection of the embodiments of the present invention.

[0021] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0022] First of all, it should be noted that epoxy resin, as a commonly used polymer material, has good physical properties and chemical stability. Generally, in order to further improve its performance and meet the needs of more application scenarios, aerogel can be added to epoxy resin to significantly improve its thermal insulation performance, mechanical properties and durability. For example, in the prior art, graphene oxide aerogel was prepared by a sol-gel method, and then a low-viscosity epoxy resin was added to the molded aerogel to prepare an epoxy resin composite material with graphene oxide as the skeleton, which effectively improved the storage modulus. Graphene aerogel with a Janus structure was synthesized using a compression-annealing assembly method, and then a multifunctional graphene aerogel / epoxy resin composite material with a Janus structure was prepared, which can greatly improve the conductivity of the composite material.

[0023] Secondly, it should be noted that, in the current prior art, although epoxy resin composite materials can be prepared using graphene oxide, sodium alginate, etc. as additives, most of them are prepared using graphene oxide or sodium alginate alone as raw materials and using aerogel technology. It is relatively rare to use graphene oxide and sodium alginate as raw materials simultaneously. Moreover, because graphene oxide (GO) contains polar groups such as epoxy, carboxyl, and hydroxyl groups, it has new properties such as strong dispersibility, compatibility, hydrophilicity, and easy surface modification. Sodium alginate (SA) belongs to biomass polysaccharide materials, has excellent biocompatibility and degradability, and is easily prepared into gel materials. Epoxy resin has excellent physical and mechanical and electrical insulation properties, as well as good material bonding properties, and is widely used in various fields such as coatings, composite materials, casting materials, adhesives, etc. Although, composite materials can be prepared by adding materials to epoxy resin to enhance tensile strength and shear strength. However, when preparing composite materials by adding graphene oxide, sodium alginate, etc. to epoxy resin, there is often a problem of reduced tensile strength due to the reduced degree of cross-linking between the added materials and the epoxy resin.

[0024] Generally speaking, the tensile strength of common epoxy resins is between 40-100MPa. The tensile strength of epoxy resin plays an important role in materials science. For example, epoxy resin itself has high strength and hardness. Epoxy resin can be injected into wood to fill gaps, thereby improving the mechanical properties and stability of wood. In the application of composite materials, epoxy resin composites have high tensile strength and elastic modulus, which makes epoxy resin composites perform well in applications requiring high strength and high rigidity. In addition, epoxy resin has good chemical resistance and electrical insulation properties, and can maintain stable performance in harsh environments. In short, designing a method for preparing epoxy resin composites using graphene oxide and sodium alginate has become a problem that urgently needs to be solved.

[0025] Therefore, in order to solve the problem of reduced tensile strength and shear strength when preparing epoxy resin composite materials by adding graphene oxide and sodium alginate in the prior art, the embodiments of the present invention provide a composite aerogel-reinforced epoxy resin material and its preparation method and application. The composite aerogel-reinforced epoxy resin material is specifically a graphene oxide / sodium alginate composite aerogel-reinforced epoxy resin material, which includes the following raw materials:

[0026] Composite aerogel, epoxy resin component A, silane coupling agent;

[0027] The composite aerogel is prepared using graphene oxide aqueous dispersion and sodium alginate aqueous solution as raw materials.

[0028] In an embodiment of the present invention, the composite aerogel-reinforced epoxy resin material is prepared by using a composite aerogel prepared from a graphene oxide aqueous dispersion and a sodium alginate aqueous solution as an additive material, which is added to the epoxy resin component A and combined with the effect of a silane coupling agent. Through effective regulation of the ratio, hydrogen bonds and cross-linking reactions can be generated between the active groups on the surface of the graphene oxide and the sodium alginate, the coupling agent, and the epoxy resin, thereby improving the tensile strength and shear strength of the epoxy resin. This solves the problem of reduced tensile strength and shear strength when preparing epoxy resin composite materials by adding graphene oxide and sodium alginate in the prior art. Although graphene oxide and sodium alginate are used simultaneously, the tensile strength and shear strength can also be effectively improved, and the preparation method is simple. Compared with the use of graphene oxide or sodium alginate alone, the preparation technology of epoxy resin composite materials has been broadened.

[0029] It should be noted that, in the prior art, graphene oxide or sodium alginate alone is usually used to prepare epoxy resin composite materials, because the use of graphene oxide and sodium alginate at the same time usually results in a decrease in tensile strength and shear strength. The embodiments of the present invention utilize the characteristics of graphene oxide and sodium alginate to prepare graphene oxide / sodium alginate composite aerogels, and mix them with epoxy resin to explore the effect of composite aerogels with different graphene oxide contents on the mechanical properties of epoxy resin. Through effective regulation of the ratio, hydrogen bonds and cross-linking can be generated between the active groups on the surface of graphene oxide and sodium alginate, coupling agents, and epoxy resin, thereby improving the tensile strength and shear strength of the epoxy resin.

[0030] As another preferred embodiment of the present invention, the composite aerogel is a porous graphene oxide / sodium alginate composite aerogel (GO / SA) prepared by freeze-drying and post-crosslinking with calcium chloride using graphene oxide aqueous dispersion and sodium alginate aqueous solution as raw materials.

[0031] As another preferred embodiment of the present invention, the freeze-drying method is to perform freeze-drying in a freeze dryer at -10°C to -100°C, and take out when the temperature reaches room temperature.

[0032] Preferably, the freeze-drying temperature of the freeze-drying method is -62.8°C. Specifically, after the graphene oxide aqueous dispersion and the sodium alginate aqueous solution are mixed as raw materials to form a uniform gel, the gel is placed in a freeze dryer for freeze drying (-62.8°C) and taken out when the temperature reaches room temperature.

[0033] As another preferred embodiment of the present invention, the post-crosslinking method of calcium chloride is to soak in a saturated calcium chloride alcohol solution after freeze-drying, and then wash and dry.

[0034] Furthermore, the calcium chloride post-crosslinking method is to soak it in a 14% saturated calcium chloride alcohol solution after freeze drying, place it at room temperature for a period of time, then wash it with alcohol to remove residual calcium chloride, and then put it into an electric constant temperature blast drying oven for drying.

[0035] As another preferred embodiment of the present invention, in the composite aerogel, the mass content of graphene oxide is 30%-90%.

[0036] Preferably, in the composite aerogel, the mass content of graphene oxide is one of 50%, 60%, 70%, 80%, and 85%.

[0037] As another preferred embodiment of the present invention, in the composite aerogel, the mass content of graphene oxide is 45%-55%.

[0038] Preferably, in the composite aerogel, the mass content of graphene oxide is 50%.

[0039] Further preferably, the preparation method of the composite aerogel is to weigh 0.2432g of reagent-grade graphene oxide aqueous dispersion at room temperature and disperse it in 12ml of a 2% sodium alginate aqueous solution by mass. Add a magnet to a beaker and place it in a heat-collecting constant-temperature heating magnetic stirrer for stirring (r=20, T=40min / piece, room temperature) until a uniform gel is formed. Then pour the uniform gel into a mold and place it in a freeze dryer for freeze drying (-62.8°C), and take it out when the temperature reaches room temperature. In order to ensure complete cross-linking of the sodium alginate, the freeze-dried gel is soaked in a 14% saturated calcium chloride alcohol solution and placed at room temperature for 8 hours. Then wash it three times with alcohol to remove residual calcium chloride. In order to completely volatilize the alcohol, the aerogel is placed in an electric constant-temperature blast drying oven set at 40°C and dried for 12 hours to obtain a composite aerogel material (GO / SA).

[0040] As another preferred embodiment of the present invention, the epoxy resin component A comprises the following components in parts by weight: 2-20 parts by weight of epoxy resin component; 1-10 parts by weight of curing agent; 60-90 parts by weight of conductive filler; and 0-2.5 parts by weight of defoaming agent.

[0041] Specifically, epoxy resin is a high molecular weight polymer and a thermosetting resin. It is typically a condensation product of epichlorohydrin and bisphenol A or a polyol. Due to the chemical activity of the epoxy group, it can be ring-opened with various compounds containing active hydrogen, which then cures and cross-links to form a network structure.

[0042] Preferably, the epoxy resin component is any one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, and tetraglycidylamine epoxy resin.

[0043] As another preferred embodiment of the present invention, the defoaming agent is any one or more of 6201, BYK-141 or BYK-053.

[0044] As another preferred embodiment of the present invention, the curing agent is any one or more of m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, and m-xylylenediamine.

[0045] As another preferred embodiment of the present invention, the conductive filler can be common conductive materials such as carbon black, silver powder or nano-silicon dioxide and other nano-powder fillers. The specific selection can refer to the products in the existing technology and is not limited here. Carbon black can usually be used as the conductive filler.

[0046] As another preferred embodiment of the present invention, the epoxy resin component A may further include an appropriate amount of a curing accelerator, wherein the curing accelerator is one or more of 2-ethyl-4-methylimidazole, 2,4,6-tris(dimethylaminomethyl)phenol, a boron trifluoride-triethylamine complex, and the like. Typically, the amount of the curing accelerator added is 4-15% by weight of the epoxy resin component.

[0047] As another preferred embodiment of the present invention, the silane coupling agent can be a vinyl silane coupling agent, such as A151 (vinyl triethoxysilane) and A171 (vinyl trimethoxysilane); an amino silane coupling agent, such as Si-550 (amino functional silane); an epoxy silane coupling agent, such as KH-550γ-aminopropyl triethoxysilane and KH-560 (γ-glycidyloxypropyl trimethoxysilane); a thiol silane coupling agent, such as Si-69 (bis-[γ-(triethoxysilyl)propyl] tetrasulfide); or a diamine silane coupling agent, such as Si-780 (difunctional diamine silane). Specific options can be selected as needed.

[0048] More preferably, the silane coupling agent is silane coupling agent KH-550. Since epoxy resin has poor hydrophilicity, the coupling agent is added to improve the compatibility between the aerogel and the epoxy resin.

[0049] The present invention also provides a method for preparing a composite aerogel-reinforced epoxy resin material. The method for preparing a composite aerogel-reinforced epoxy resin material specifically comprises the following steps:

[0050] An appropriate amount of composite aerogel and epoxy resin component A are weighed and placed in a container, and then a silane coupling agent is added and mixed evenly. The mixture is then placed in a mold and baked at 180-220° C. for 1-3 hours to obtain the composite aerogel reinforced epoxy resin material.

[0051] Preferably, the preparation method of the composite aerogel reinforced epoxy resin material comprises the following steps:

[0052] 1) At room temperature, 0.2432 g, 0.3645 g, 0.5571 g, 0.9612 g, and 1.4300 g of reagent-grade graphene oxide aqueous dispersion were weighed and dispersed in 12 ml of a 2% sodium alginate aqueous solution (the graphene oxide contents were 0.24%, 0.40%, 0.89%, 1.06%, and 1.20%, respectively). A magnetic stirrer was added to the beaker and stirred in a heat-collecting constant-temperature magnetic stirrer (r = 20, T = 40 min / strain, room temperature) until a uniform gel was formed.

[0053] 2) Pour the uniform gel into a mold and place it in a freeze dryer for freeze drying (-62.8°C), and take it out when the temperature is at room temperature. Soak the freeze-dried gel in a 14% saturated calcium chloride alcohol solution and leave it at room temperature for 8 hours. Wash it three times with alcohol to remove the residual calcium chloride. In order to completely volatilize the alcohol, place the aerogel in an electric constant temperature blast drying oven set at 40°C and dry it for 12 hours to obtain a composite aerogel, in which the mass content of graphene oxide is 50%, 60%, 70%, 80%, and 85%, respectively (corresponding to composite aerogels prepared using 0.2432g, 0.3645g, 0.5571g, 0.9612g, and 1.4300g of reagent-grade graphene oxide aqueous dispersion, respectively).

[0054] 3) Weigh appropriate amounts of the composite aerogel and epoxy resin component A separately and place them in a beaker. Add appropriate amounts of silane coupling agent KH-550 to the beaker in four portions and stir thoroughly. Pour the mixture of aerogel and epoxy resin component A into a mold and bake at 200°C for 2 hours to obtain a composite aerogel-reinforced epoxy resin material.

[0055] An embodiment of the present invention further provides a composite aerogel-reinforced epoxy resin material prepared by the above-mentioned method for preparing the composite aerogel-reinforced epoxy resin material.

[0056] Embodiments of the present invention also provide a use of the aforementioned composite aerogel-reinforced epoxy resin material in the preparation of composite materials. This material is particularly suitable for the preparation of resin-based composite materials. Specifically, thermosetting resins, thermoplastic resins, and various modified or blended matrices can be used as component materials, while the composite aerogel or composite aerogel-reinforced epoxy resin material of the embodiments of the present invention is used as a reinforcement to improve the tensile and shear strength of the composite material.

[0057] The technical effects of the composite aerogel reinforced epoxy resin material according to the embodiment of the present invention are further described below by listing specific examples.

[0058] It should be noted that in the following examples, the following instruments are mainly used:

[0059] Analytical balance, Shimadzu International Trading (Shanghai) Co., Ltd.; thermal collector constant temperature heating magnetic stirrer (model DF-101S), Bangsi Instrument Technology (Shanghai) Co., Ltd.; electric constant temperature blast drying oven (model DHG-9140A), Shanghai Sanfa Scientific Instrument Co., Ltd.; infrared spectrometer (model Nicolet iS10), Nicolet Instruments, USA; freeze dryer (model SCIENTZ-12N), Ningbo Xinyun Biotechnology Co., Ltd.; X-ray diffractometer (model DX-2700), Dandong Haoyuan Instrument Co., Ltd.; Phenom desktop scanning electron microscope (model Phenom Pro), Funa Scientific Instrument (Shanghai) Co., Ltd.; microcomputer-controlled electronic universal testing machine (model WDW-30A), Jinan Kairui Testing Machine Manufacturing Co., Ltd.; thermogravimetric analyzer (model HCT), Beijing Hengjiu Scientific Instrument Factory.

[0060] Example 1

[0061] A composite aerogel, specifically a graphene oxide / sodium alginate composite aerogel prepared using a graphene oxide aqueous dispersion and a sodium alginate aqueous solution as raw materials.

[0062] In this embodiment, the preparation method of the composite aerogel specifically includes the following steps:

[0063] 1) At room temperature, weigh 0.2432 g of reagent-grade graphene oxide aqueous dispersion and disperse it in 12 ml of a 2% sodium alginate aqueous solution. Add a magnet to a beaker and stir the mixture in a heat-collecting constant-temperature magnetic stirrer (20 rpm, room temperature) until a uniform gel forms.

[0064] 2) Pour the uniform gel into a mold and place it in a freeze dryer for freeze drying (-62.8°C), and take it out when the temperature reaches room temperature. To ensure complete cross-linking of the sodium alginate, soak the freeze-dried gel in a 14% saturated calcium chloride alcohol solution and place it at room temperature for 8 hours. Wash it three times with alcohol to remove the residual calcium chloride. In order to completely evaporate the alcohol, place the aerogel in an electric constant temperature blast drying oven set at 40°C and dry it for 12 hours to obtain a composite aerogel material, in which the mass content of graphene oxide is 50%, marked as GO / SA-1.

[0065] Example 2

[0066] Compared with Example 1, except that the amount of reagent-grade graphene oxide aqueous dispersion used is 0.3645 g, other conditions are the same as Example 1. The prepared composite aerogel material is labeled GO / SA-2, in which the mass content of graphene oxide is 60%.

[0067] Example 3

[0068] Compared with Example 1, except that the amount of reagent-grade graphene oxide aqueous dispersion used is 0.5571 g, other conditions are the same as Example 1. The prepared composite aerogel material is labeled GO / SA-3, in which the mass content of graphene oxide is 70%.

[0069] Example 4

[0070] Compared with Example 1, except that the amount of reagent-grade graphene oxide aqueous dispersion used is 0.9612 g, other conditions are the same as Example 1. The prepared composite aerogel material is labeled GO / SA-4, in which the mass content of graphene oxide is 80%.

[0071] Example 5

[0072] Compared with Example 1, except that the amount of reagent-grade graphene oxide aqueous dispersion used is 1.4300 g, other aspects are the same as Example 1. The prepared composite aerogel material is labeled GO / SA-5, in which the mass content of graphene oxide is 85%.

[0073] Example 6

[0074] In this example, appropriate amounts of the GO / SA-1, GO / SA-2, GO / SA-3, GO / SA-4, and GO / SA-5 composite aerogels prepared in Examples 1-5 and an equal amount of epoxy resin component A were weighed and placed into five beakers. An appropriate amount of silane coupling agent KH-550 was added to each beaker in four portions and stirred thoroughly. The mixture of the composite aerogels and epoxy resin component A in the five beakers was then used to prepare a shearing jig and cast into a tensile specimen mold. The mixture was then baked at 200°C for 2 hours, yielding five composite aerogel-reinforced epoxy resin materials containing the corresponding components. Each composite aerogel-reinforced epoxy resin material had a prepared shearing jig and tensile specimen.

[0075] Among them, the specific formulas of the five composite aerogel-reinforced epoxy resin materials containing corresponding components are shown in Table 1. The formulas 1, 2, 3, 4, and 5 are marked as GO / SA-1 / epoxy resin component A, GO / SA-2 / epoxy resin component A, GO / SA-3 / epoxy resin component A, GO / SA-4 / epoxy resin component A, and GO / SA-5 / epoxy resin component A, respectively.

[0076] Table 1 Formulas for different concentration gradient designs

[0077]

[0078] Table 1 shows that the composite aerogel-reinforced epoxy resin material prepared using GO / SA-1 as raw material, labeled GO / SA-1 / Epoxy Resin Component A, contains 0.5% GO / SA-1 by weight, 99.49% epoxy resin Component A by weight, and 0.01% silane coupling agent KH-550 by weight. Other formulations can be found in the GO / SA-1 / Epoxy Resin Component A.

[0079] In this embodiment, the epoxy resin component A comprises the following components, calculated by mass percentage: 15% epoxy resin component; 8% curing agent; 75% conductive filler; and 2% defoaming agent. The epoxy resin component is bisphenol A epoxy resin. The defoaming agent is BYK-141; and the curing agent is m-phenylenediamine.

[0080] Example 7

[0081] In this example, the GO / SA-1 sample of Example 1 was used as a test sample, and the structural groups in the components of the composite aerogel were analyzed by infrared spectroscopy. At the same time, graphene oxide (labeled as GO) and sodium alginate (labeled as SA) were used as comparative references, and the structural groups in the components of the aerogel were analyzed by infrared spectroscopy under the same conditions. Specifically, the KBr pellet method was used to perform infrared characterization on GO, SA, and the GO / SA-1 composite material, respectively, with a scanning range of 400 cm -1 ~4000cm -1 The infrared spectrum obtained is as follows Figure 1 shown.

[0082] from Figure 1 It can be seen that in the infrared spectrum of GO, 3452cm -1 The broad absorption peaks near 1645 cm are the stretching vibration absorption peaks of the hydroxyl group (-OH) in the molecule. -1 、1493cm -1 and 1157cm -1 The absorption peaks at 3460cm are due to the vibration absorption peaks of C=C, C-OH, and COC in the molecule. It can be seen that graphene oxide contains hydrophilic functional groups such as hydroxyl and epoxy groups, which can participate in related chemical reactions. For sodium alginate, 3460cm -1 The broad absorption peak near 1647 cm is due to the stretching vibration of hydroxyl (-OH). -1 The absorption peak at 2941cm is due to the symmetrical and asymmetrical stretching vibration of the carboxyl group (-COOH) in the molecular structure. -1 The absorption peak at 3394 cm is caused by the CH stretching vibration on the six-membered ring in sodium alginate. For graphene oxide / sodium alginate composite aerogel GO / SA-1, the absorption peak at 3394 cm-1 、1595cm -1 and 1410cm -1 The peaks at the bottom are the hydroxyl (-OH) stretching vibration absorption peak, the asymmetric stretching vibration peak of the carboxyl (-COOH) and the symmetric stretching vibration peak. By comparing the infrared spectra of GO, SA, and GO / SA-1, it can be seen that the vibration absorption peaks of the composite aerogel have all shifted to the lower wavenumber direction, indicating that the addition of graphene oxide to the sodium alginate system will not have a significant impact on the original molecular structure. The change in the peak wavenumber of the vibration peak may be due to the hydrogen bonding between graphene oxide and the sodium alginate macromolecules.

[0083] Example 8

[0084] The surface morphology of the aerogel samples prepared in Examples 1-5 was analyzed using a scanning electron microscope (SEM) to obtain the following images: Figure 2 As shown. Among them, Figure 2 Figure (a) is a digital photo of GO / SA-1, GO / SA-2, GO / SA-3, GO / SA-4, and GO / SA-5 prepared in Examples 1-5. It can be seen from the actual objects in the beaker that the GO / SA series composite aerogel materials can maintain a relatively complete cubic structure. Figure 2 Figures (b), (c), (d), (e) and (f) are scanning electron microscope (SEM) images of GO / SA-1, GO / SA-2, GO / SA-3, GO / SA-4 and GO / SA-5, respectively. Figure 2 (b) and (c) are GO / SA-1 and GO / SA-2 composite aerogel materials, respectively. From the figure, we can clearly see the honeycomb network structure with many pores, but the porous structure is somewhat disordered, which may be caused by the uneven dispersion of graphene oxide and sodium alginate. Figure 2 (c) is the GO / SA-3 composite aerogel material. From the figure, it can be found that the pores are significantly reduced and there is a layer superposition phenomenon. Figure 2 (e) and (f) are GO / SA-4 and GO / SA-5 composite aerogel materials respectively. It is obvious from the figure that graphene oxide is stacked and piled up together. The main reason may be that when the amount of GO in the composite aerogel material is too large, the GO sheets will overlap, making it difficult to combine with SA. Figure 2 From the SEM image, we can see some small particles on the GO / SA composite aerogel material. These small particles are probably caused by the calcium chloride not being completely washed away during the preparation process.

[0085] Example 9

[0086] In this example, the mechanical properties of the composite aerogel-reinforced epoxy resin materials labeled GO / SA-1 / epoxy resin component A, GO / SA-2 / epoxy resin component A, GO / SA-3 / epoxy resin component A, GO / SA-4 / epoxy resin component A, and GO / SA-5 / epoxy resin component A in Example 6 were tested. Specifically, the shear strength and tensile strength of the composite aerogel-reinforced epoxy resin materials were analyzed using a universal testing machine. The mechanical properties of the tensile specimens of the five prepared composite aerogel-reinforced epoxy resin materials were tested using a universal testing machine. Simultaneously, the mechanical properties of the tensile specimens of epoxy resin component A were tested under the same conditions as the reference sample. The specific mechanical property test results are shown in Table 2.

[0087] Table 2 Mechanical properties test results

[0088] Sample Tensile strength / MPa Shear strength / MPa Epoxy resin component A 45.26 11.56 GO / SA-1 / epoxy resin component A 50.60 14.48 GO / SA-2 / epoxy resin component A 44.55 11.22 GO / SA-3 / epoxy resin component A 42.15 10.25 GO / SA-4 / epoxy resin component A 40.66 9.15 GO / SA-5 / epoxy resin component A 39.85 8.63

[0089] The data in Table 2 show that when the aerogel material content in the GO / SA-2 / epoxy resin A component, GO / SA-3 / epoxy resin A component, GO / SA-4 / epoxy resin A component, and GO / SA-5 / epoxy resin A component is 0.5% of the total aerogel / epoxy resin composite, the 50% graphene oxide epoxy resin composite (i.e., GO / SA-1 / epoxy resin A component) exhibits the highest tensile and shear strengths, while the 85% graphene oxide epoxy resin composite (i.e., GO / SA-5 / epoxy resin A component) exhibits the lowest tensile and shear strengths. The tensile and shear strengths of the GO / SA-1 / epoxy resin A component are higher than those of the pure epoxy resin composite. This is likely due to hydrogen bonding and crosslinking between the active groups on the graphene oxide surface and the SA, coupling agent, and epoxy resin, which enhances the strength and shear strength of the epoxy resin. However, it was also observed that as the graphene oxide content in the composite aerogel material increased, the tensile strength and shear strength of the aerogel / epoxy resin composite material gradually decreased. The main reason may be that when the amount of GO in the composite aerogel material is too large, the GO sheets will overlap, weakening its nano-size effect and reducing the degree of cross-linking between it and the epoxy resin, resulting in a decrease in tensile strength.

[0090] Example 10

[0091] In this embodiment, the microstructure of the composite aerogel reinforced epoxy resin material is analyzed, and the scanning electron microscope (SEM) images obtained by the microstructure analysis are as follows: Figure 3 、 Figure 4 As shown, Figure 3 It is a composite aerogel reinforced epoxy resin material marked as GO / SA-1 / epoxy resin A component. Figure 4 This composite aerogel-reinforced epoxy resin material is labeled GO / SA-2 / epoxy resin component A. Analysis revealed that the cross-sectional scans of pure epoxy resin exhibit a uniform and smooth surface, while other images show a relatively rough morphology. This is due to stress concentration, crack deflection, and partial filler agglomeration caused by the addition of the composite aerogel. Figure 3 and Figure 4 The cross-sectional particle distribution of the composite aerogel-reinforced epoxy resin material in the GO / SA-3 / epoxy resin component A, the GO / SA-4 / epoxy resin component A, and the GO / SA-5 / epoxy resin component A composite aerogel-reinforced epoxy resin material showed obvious agglomeration in their cross-sectional particle distribution. The main reason may be that with the increase in graphene oxide content, the amount of GO in the composite aerogel material is too large, resulting in internal superposition, which weakens the cross-linking ability between the composite aerogel and the epoxy resin and causes obvious self-agglomeration.

[0092] In the embodiment of the present invention, graphene oxide aqueous dispersion and sodium alginate (SA) are used as raw materials, and graphene oxide / sodium alginate composite aerogel is obtained by freeze drying. Using SEM and FTIR test analysis, it can be seen that a composite aerogel reinforced epoxy resin material with a porous structure and functional groups such as hydroxyl and epoxy groups are prepared on the surface of the composite aerogel, but the content of graphene oxide has a greater influence on the porous structure of the composite aerogel. The prepared composite aerogel material is then extruded and blended with epoxy resin, and finally a tensile specimen is prepared by an injection machine. Using a universal testing machine for test analysis, it can be seen that when the amount of composite aerogel added is 0.5% and the content of graphene oxide in the composite aerogel material is 50%, the tensile strength and shear strength of the prepared composite aerogel reinforced epoxy resin material are optimal. The main reason may be the generation of hydrogen bonds and crosslinking between the active groups on the surface of graphene oxide and SA, coupling agent, and epoxy resin.

[0093] Example 11

[0094] Compared with the composite aerogel reinforced epoxy resin material labeled as GO / SA-1 / epoxy resin component A in Example 6, everything else is the same except that the freeze-drying was performed at -10°C.

[0095] Example 12

[0096] Compared with the composite aerogel reinforced epoxy resin material labeled as GO / SA-1 / epoxy resin component A in Example 6, everything else is the same except that the freeze-drying is performed at -100°C.

[0097] Example 13

[0098] Compared with the composite aerogel reinforced epoxy resin material marked as GO / SA-1 / epoxy resin component A in Example 6, except that the mass content of graphene oxide in the composite aerogel is 45%, all other aspects are the same.

[0099] Example 14

[0100] Compared with the composite aerogel reinforced epoxy resin material marked as GO / SA-1 / epoxy resin component A in Example 6, except that the mass content of graphene oxide in the composite aerogel is 55%, all other aspects are the same.

[0101] Example 15

[0102] Compared with the composite aerogel reinforced epoxy resin material marked as GO / SA-1 / epoxy resin A component in Example 6, except that the epoxy resin component is bisphenol F epoxy resin, everything else is the same.

[0103] Example 16

[0104] Compared with the composite aerogel reinforced epoxy resin material marked as GO / SA-1 / epoxy resin component A in Example 6, except that the epoxy resin component is a tetraglycidylamine type epoxy resin, everything else is the same.

[0105] Example 17

[0106] Compared with the composite aerogel reinforced epoxy resin material marked as GO / SA-1 / epoxy resin A component in Example 6, everything else is the same except that the epoxy resin component is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in equal weight proportions.

[0107] Example 18

[0108] Compared with the composite aerogel-reinforced epoxy resin material labeled as GO / SA-1 / epoxy resin A component in Example 6, except that the epoxy resin component is a mixture of bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, and tetraglycidylamine epoxy resin in equal weight proportions, everything else is the same.

[0109] According to the above results, it can be seen that the embodiment of the present invention uses graphene oxide aqueous dispersion (GO) and sodium alginate (SA) as raw materials, and obtains a porous structure of graphene oxide / sodium alginate composite aerogel (GO / SA) through freeze drying and calcium chloride post-crosslinking. Scanning electron microscopy (SEM), infrared spectroscopy (IR) and universal testing machine were used to characterize and analyze the surface micromorphology and functional group structure of the composite aerogel and the mechanical properties of the aerogel / epoxy resin composite material. The changes in the porous structure of the composite aerogel prepared with different graphene oxide concentrations and the influence of the mechanical properties of the epoxy resin doped with the graphene oxide were explored. Through comparative experiments, it can be seen that when the added graphene oxide content is 50%, the porous structure of the composite aerogel is obvious, and the maximum tensile strength of the composite aerogel reinforced epoxy resin material is 50.6Mpa, and the maximum shear strength is 14.48Mpa. The present invention uses a composite aerogel prepared from a graphene oxide aqueous dispersion and a sodium alginate aqueous solution as an additive material, adds it to the epoxy resin component A, and cooperates with the action of a silane coupling agent. Through the rational use of raw materials and effective regulation of the ratio, hydrogen bonds and crosslinking reactions are generated between the active groups on the surface of the graphene oxide and the sodium alginate, coupling agent, and epoxy resin, thereby improving the tensile strength and shear strength of the epoxy resin. This solves the problem of reduced tensile strength and shear strength in the preparation of epoxy resin composite materials by adding graphene oxide and sodium alginate in the prior art. Moreover, the preparation method provided by the present invention is simple, effectively broadens the technology for preparing epoxy resin composite materials, and has broad market prospects.

[0110] It should also be noted that most existing technologies use graphene oxide as an aerogel material to be added to epoxy resin, or simply prepare sodium alginate / graphene oxide composite aerogels. For example, Chinese patent publication number CN 106853296B discloses an oil-water separation type sodium alginate / graphene oxide composite aerogel. The composite aerogel is primarily used for oil-water separation, with high separation efficiency and high salt tolerance, making it suitable for high-salt marine environments. The present invention prepares a sodium alginate / graphene oxide aerogel material and then applies it to epoxy resin, thereby improving the mechanical properties of the epoxy resin.

[0111] Finally, it should be noted that the silane coupling agent KH-550 and the like used in the embodiments of the present invention are all products from existing manufacturers. For example, among the other main reagents: the graphene oxide aqueous dispersion is a reagent-grade graphene oxide aqueous dispersion produced by Suzhou Carbon Graphene Technology Co., Ltd.; sodium alginate (AR grade) is from Aladdin Chemical Reagent Co., Ltd.; anhydrous calcium chloride (AR grade) is from Tianjin Dengke Chemical Reagent Co., Ltd.; and anhydrous ethanol (AR grade) is from Sinopharm Chemical Reagent Co., Ltd. The above are all conventional additives used in the production of epoxy resin composite materials and are selected based on specific needs. These are not described in detail here.

[0112] The above describes in detail the preferred embodiments of the present invention, and describes the basic principles, main features and advantages of the present invention. However, those skilled in the art should understand that the embodiments of the present invention are not limited to the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Within the scope of knowledge possessed by ordinary technicians in this field, various changes can be made without departing from the purpose of the embodiments of the present invention. It is not necessary and impossible to list all the embodiments here. The obvious changes or modifications derived from this are still within the scope of protection of the embodiments of the present invention.

Claims

1. A composite aerogel reinforced epoxy resin material, characterized in that: The composite aerogel-reinforced epoxy resin material includes the following raw materials: composite aerogel, epoxy resin component A, and a silane coupling agent. The composite aerogel is prepared using a graphene oxide aqueous dispersion and a sodium alginate aqueous solution as raw materials. The mass content of the graphene oxide in the composite aerogel is 30%-90%. The composite aerogel is prepared by freeze-drying the graphene oxide aqueous dispersion and the sodium alginate aqueous solution as raw materials and then post-crosslinking with calcium chloride.

2. The composite aerogel reinforced epoxy resin material according to claim 1, characterized in that: In the composite aerogel, the mass content of graphene oxide is 45%-55%.

3. The composite aerogel reinforced epoxy resin material according to claim 1, characterized in that: In the preparation method of the composite aerogel, the freeze-drying method is to perform freeze-drying at -10°C to -100°C; the calcium chloride post-crosslinking method is to soak in a saturated calcium chloride alcohol solution and then wash and dry.

4. The composite aerogel reinforced epoxy resin material according to claim 3, characterized in that: The epoxy resin component A comprises the following raw materials in parts by weight: 2-20 parts by weight of epoxy resin component; 1-10 parts by weight of curing agent; 60-90 parts by weight of a conductive filler; 0-2.5 parts by weight of a defoaming agent.

5. The composite aerogel reinforced epoxy resin material according to claim 4, characterized in that: The epoxy resin component is any one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, and tetraglycidylamine epoxy resin.

6. The composite aerogel reinforced epoxy resin material according to claim 5, characterized in that: The curing agent is any one or more of m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone and m-xylylenediamine.

7. A method for preparing a composite aerogel reinforced epoxy resin material according to any one of claims 1 to 6, characterized in that: The following steps are involved: An appropriate amount of composite aerogel and epoxy resin component A are weighed and placed in a container, and then a silane coupling agent is added and mixed evenly, and then placed in a mold and baked at 180-220° C. to obtain the composite aerogel reinforced epoxy resin material.

8. Use of the composite aerogel reinforced epoxy resin material according to claim 1, 2, 3, 4, 5 or 6 in preparing a resin-based composite material.

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