Highly Absorbent Electromagnetic Shielding and Thermal Conductive Epoxy Composite Material, Preparation Method and Use

Abstract

The present invention belongs to the field of materials science, and specifically discloses a highly absorbent electromagnetic shielding and thermally conductive epoxy composite material, a preparation method and uses thereof. The preparation method of the composite material is as follows: BN, MWCNT and cellulose are mixed evenly and then form a wavy oriented structure through an ice template, and after vacuum drying, it is carbonized at high temperature. Subsequently, the epoxy resin curing components are stirred evenly and then poured into the ceramic skeleton through vacuum assistance, and the poured skeleton is cured at high temperature to obtain the BN / MWCNT / EP composite material. The material is mainly composed of a ceramic skeleton composed of boron nitride (BN) and multi-walled carbon nanotubes (MWCNT) and an epoxy matrix. Under the extrusion force of ice crystal growth, BN is wound by MWCNT and overlaps with each other to form a thermal conduction path. At the same time, MWCNT forms an electrical conduction path and absorbs electromagnetic waves through multiple reflections to cause dielectric loss. The prepared epoxy resin composite material has high absorbent electromagnetic shielding efficiency and thermal conductivity, and at the same time, its mechanical properties are also greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of materials for semiconductor packaging, and particularly relates to an electromagnetic shielding and heat-conducting epoxy composite material with high absorption, and a preparation method and use thereof. Background Art

[0002] As an important embedding material for semiconductor chips, epoxy resin has been widely used in the field of electronic packaging due to its excellent mechanical properties, unique dimensional stability, easy processability, and excellent corrosion resistance. With the development of 6G technology, the millimeter-wave era is approaching. The emission of electromagnetic waves not only causes serious electromagnetic pollution but also leads to failures of sensitive electronic systems, endangering human health. In addition, the high power and high integration of electronic components have made the requirement for heat dissipation more urgent. In actual scenarios, out-of-plane heat dissipation is more needed. Therefore, traditional single-functional composite materials can no longer meet the requirements of the development of modern electronic technology. However, how to provide thermal conductivity and electromagnetic shielding while maintaining good mechanical properties is a major challenge for epoxy composite materials.

[0003] A commonly used solution is to fill conductive and heat-conducting particles into epoxy resin to form dense conductive and heat-conducting paths to improve the electromagnetic shielding efficiency and thermal conductivity of the composite material. The key lies in solving the problem of agglomeration of various fillers in the matrix. For example, the Chinese patent document with the publication number CN109679280A mixes titanium dioxide-coated graphite and epoxy resin evenly, then adds boron nitride (BN), and continues to stir to obtain composite particles. Then, the composite particles are granulated twice with epoxy resin. Through multiple granulations by an extruder, the fillers are fully dispersed in the epoxy matrix to avoid partial concentration. The BN in the composite particles and the conductive graphite form conductive and heat-conducting channels. The obtained material has a thermal conductivity of 6.8 W / (m·K) and a shielding efficiency of 60 dB. The Chinese patent document with the publication number CN109265927A fills epoxy resin containing heat-conducting fillers diluted with acetone into copper foam doped with carbon nanotubes, concentrates and cures it to obtain copper foam / epoxy resin electronic packaging materials. The thermal conductivity is as high as 55.2 W / (m·K), and the electromagnetic shielding performance reaches 57.9 dB. Copper foam itself serves as a prefabricated structure. After the heat-conducting fillers are mixed in the epoxy diluted with acetone, it is more conducive to random dispersion and reduces agglomeration. However, copper foam has too high a density, and its combination with the matrix is poor. Moreover, a large amount of BN is added to the epoxy, accounting for 40%-60% of the mass of the copper foam / epoxy resin composite material, which affects the mechanical properties of the composite material.

[0004] There are problems with the existing technology of efficiently directional forming filler skeletons: the electrical conductivity is too high, resulting in high reflectivity or poorly handled phonon scattering between fillers, and the thermal conductivity is too low. On the other hand, in the directional skeleton, electromagnetic waves can easily pass through the material along the directional gaps. The existing technology cannot produce a multifunctional ceramic skeleton with high thermal conductivity and electromagnetic shielding efficiency, light weight and sufficient strength. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for preparing a highly absorbing electromagnetic shielding and heat-conducting epoxy composite material, so as to overcome the problems of large skeleton specific weight, poor bonding between fillers, large filling amount, and large interface thermal resistance in the existing technology for improving the thermal conductivity and electromagnetic shielding performance of epoxy resin. The present invention constructs a lightweight and stable 3D ceramic skeleton with BN and MWCNT by ice template method. The ice template method arranges the fillers in a directional manner, so that a 3D skeleton can be constructed at a low filling rate; by introducing silane, the interface bonding between BN and MWCNT is enhanced at high temperature, so that the ceramic skeleton completes the construction of a dense thermal and electrical conductive network, which can greatly improve the thermal conductivity and electromagnetic shielding efficiency of the epoxy composite material.

[0006] To achieve the above object, the present invention adopts the following technical solution: a method for preparing a highly absorbing electromagnetic shielding and thermally conductive epoxy composite material, comprising the following steps:

[0007] S1, a trimethoxy silane coupling agent and deionized water are mixed in equal volumes, and then a 10 vol% HCl solution is added, wherein the volume ratio of the trimethoxy silane coupling agent to the HCl solution is 5:1, and then placed in an ice bath and stirred for hydrolysis for 0.1-5h to obtain a silane hydrolysis solution;

[0008] S2, add 0.5-10 parts by weight of boron nitride (BN) and 0.05-5 parts by weight of a surfactant to 10-60 parts by weight of deionized water, stir well, add multi-walled carbon nanotubes (MWCNT), the mass ratio of BN to MWCNT is 1:1-20:3, after being evenly dispersed, add 1-5 parts by weight of carbon nanofibers (CNF), and then add 0.4-3 parts by weight of a silane hydrolysis solution, and stir to obtain a mixed solution;

[0009] S3. Pour the mixed solution into the mold under the temperature condition of -196-0°C and cover the bottom of the mold. After it is completely frozen, continue to add the mixed solution to cover the formed frozen layer, repeat several times until the frozen layer reaches 2-3mm, freeze-dry the frozen layer, and then sinter it at 300-1000°C for 1-10h to obtain a 3DBN / MWCNT aerogel ceramic skeleton;

[0010] S4. After stirring the epoxy resin curing component, i.e., EP, at 20 - 90 °C, it is immersed in the 3DBN / MWCNT aerogel ceramic framework under vacuum assistance, and then thermally cured to obtain the BN / MWCNT / EP composite material.

[0011] As a further improvement in the preparation method of the high - absorption electromagnetic shielding and heat - conducting epoxy composite material:

[0012] Preferably, the trimethoxysilane coupling agent described in step S1 is one or a combination of two or more of 3 - aminopropyltrimethoxysilane (APTES), methoxytrimethoxysilane (MTMS), octyltrimethoxysilane, γ - glycidoxypropyltrimethoxysilane, N-(β - aminoethyl)-γ - aminopropyltrimethoxysilane, γ - methacryloxypropyltrimethoxysilane, γ - mercaptopropyltrimethoxysilane.

[0013] Preferably, the surfactant described in step S2 is one or a combination of two or more of poly(diallyldimethylammonium chloride) (PDDA), cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, ammonium dodecyl sulfate, dodecylbenzenesulfonic acid.

[0014] Preferably, the particle size of the boron nitride, i.e., BN, described in step S2 is 0.1 - 100 μm.

[0015] Preferably, the specific operation of thermal curing in step S4 is: placing the BN / MWCNT aerogel ceramic framework immersed with the epoxy resin curing component at 90 - 200 °C for high - temperature curing for 1 - 9 h.

[0016] Preferably, the components of the epoxy resin curing component EP in step S3 are as follows: 50 - 100 parts by weight of epoxy resin, 40 - 100 parts by weight of curing agent, 1 - 10 parts by weight of curing accelerator, and 2 - 5.25 parts by weight of flame retardant.

[0017] Preferably, the epoxy resin is one or a combination of two or more of bisphenol A diglycidyl ether, methyl - substituted vinyl cyclohexene dioxide epoxy resin, triglycidyl isocyanurate; or, the curing agent is one or a combination of two of methylhexahydrophthalic anhydride, triethylenetetramine.

[0018] Preferably, the curing accelerator is 2,4,6 - tris(dimethylaminomethyl)phenol, and the flame retardant is a phosphorus - based flame retardant.

[0019] The second object of the present invention is to provide a high - absorption electromagnetic shielding and heat - conducting epoxy composite material prepared by the above - mentioned preparation method.

[0020] A third object of the present invention is to provide a use of the above high-absorption electromagnetic shielding and heat-conducting epoxy composite material in the field of semiconductor packaging.

[0021] The beneficial effects of the present invention compared with the prior art are as follows:

[0022] 1) The present invention provides a preparation method of a high electromagnetic shielding absorption and heat-conducting ceramic skeleton epoxy composite material. First, an HCl solution is added to an aqueous solution of a trimethoxysilane coupling agent to accelerate the hydrolysis of the silane coupling agent. The trimethoxysilane has a fast hydrolysis rate, and three hydroxyl groups are generated after hydrolysis, which is more likely to interact with nanocellulose and multi-walled carbon nanotubes. Boron nitride (BN) and multi-walled carbon nanotubes (MWCNT) are mixed and then added to the silane hydrolysis solution, and a 3D BN / MWCNT aerogel ceramic skeleton is prepared by the ice-templating method. Among them, MWCNT and nanocellulose connect BN sheets together, and the hydrolyzed silane is used to bind to BN and MWCNT through intermolecular interactions. After the 3D skeleton is carbonized at high temperature, the inertness of the BN surface is improved, which not only reduces the interfacial thermal resistance between fillers but also enhances the wetting effect between the filler and the epoxy matrix. The carbonized ceramic skeleton is impregnated and cured with epoxy resin and auxiliary materials to obtain an epoxy composite material. Among them, the above-mentioned flaky BN is hexagonal BN, MWCNT is carboxyl-modified MWCNT, and nanocellulose is obtained by TEMPO oxidation method.

[0023] a. The epoxy composite material with high electromagnetic shielding absorption and heat conduction provided by the present invention uses two materials with different scales, flaky BN and carbon nanotubes, as fillers. BN itself has excellent heat conduction performance and insulation ability, while MWCNT can form phonon channels and greatly enhance the mechanical properties and interfacial bonding properties of epoxy resin. Moreover, MWCNT can form multi-site and multi-dimensional heat transfer channels between flaky BN. Not only that, due to the small density of MWCNT, a small amount of carbon tubes have enough volume to form a dense conductive network, thereby endowing the material with electromagnetic shielding function.

[0024] b. Through the ice-templating method, the fillers are oriented out-of-plane. Compared with the random distribution method, this distribution method of fillers has a greater probability of mutual overlap of BN heat-conducting fillers. At the same time, the low-density MWCNT is more likely to entangle BN. Under multiple physical forces, the construction of the heat-conducting network mainly composed of BN is more complete. Since BN and MWCNT are dispersed in water together, stirring at low medium viscosity also makes it easier for BN and MWCNT to be fully mixed and reduces agglomeration. Therefore, the conductive network formed by MWCNT can be denser in the skeleton.

[0025] c. The carbonized 3D aerogel ceramic skeleton enhances the strength of the skeleton structure. Silane reacts completely at high temperature and combines with MWCNT and nanocellulose through dehydration condensation between hydroxyl groups. It also forms a glassy amorphous bond with BN surface atoms at high temperature, thus combining various fillers into a whole. On the other hand, SiO 2 Combined with the BN surface, it reduces the inertness of the BN surface and enhances the interfacial force between BN and the epoxy matrix.

[0026] d. Regarding the electromagnetic shielding function, the epoxy composite material composed of the ceramic skeleton also has its unique features. Since the orientation of the ice template is generally vertically upward, but in the present invention, the sample is frozen into blocks layer by layer, and the temperature transfer from top to bottom makes the ice crystals grow vertically, but the newly covered mixed liquid is equivalent to a heat source, which changes the orientation angle formed at the bottom, and there are wrinkles on its surface, and there is an angle deviation from the vertical line. It does not grow at 90° to the ground, but is wavy in the vertical direction. The addition when the upper surface is not completely frozen is to ensure that each layer of coverage can ensure continuous growth into the whole sample, and avoid sample cracking during the subsequent carbonization process. Therefore, when the electromagnetic wave is injected, the electromagnetic wave does not penetrate the material in the injection direction. Secondly, multiple reflections occur in the skeleton network composed of MWCNT and BN. At the electromagnetic wave incident surface, the material is almost insulating, so the electromagnetic wave energy can almost completely enter the interior of the material, and rarely reflects on the surface. The multiple internal reflections can cause dielectric loss of the electromagnetic wave, causing it to dissipate in the form of heat energy. Therefore, absorption is the main mechanism in the electromagnetic shielding of this material, and its absorption rate exceeds 50%.

[0027] 2) The epoxy resin composite material prepared by the present invention is mainly composed of a ceramic skeleton and an epoxy matrix composed of BN (5-100 μm) and MWCNT. BN is entangled by MWCNT under the extrusion force of ice crystal growth and overlaps with each other to form a heat conduction path. At the same time, MWCNT forms a conductive path, which absorbs the electromagnetic wave through dielectric loss caused by multiple reflections. It has high absorption electromagnetic shielding effectiveness and thermal conductivity, and the mechanical properties are also greatly improved. The typical value of electromagnetic shielding effectiveness is 10-80 dB, the absorption rate is more than 50%, and the typical value of thermal conductivity can reach 0.6-3W / (m·K). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 These are scanned images of the carbonized 3DBN / MWCNT aerogel ceramic skeleton in Example 2 of the present invention at two different magnifications of 300 and 15000; (a) is 300 times and (b) is 15000 times.

[0029] Figure 2These are in-plane and out-of-plane cross-sectional scans of the 3DBN / MWCNT epoxy composite material prepared in Example 2 of the present invention at different magnifications; (a) is an out-of-plane cross-sectional image magnified 30 times, (b) is an out-of-plane cross-sectional image magnified 5000 times, and (c) is an in-plane cross-sectional image magnified 5000 times. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a ceramic skeleton epoxy composite material with high electromagnetic shielding absorption and thermal conductivity, which specifically includes the following steps:

[0033] S1, 2.5 ml of methyltrimethoxysilane and 2.5 ml of deionized water were mixed in equal volumes, and then 0.5 ml of HCl solution (10 vol%) was added, and the mixture was stirred in an ice bath for hydrolysis for 0.5 h to obtain a silane hydrolysis solution;

[0034] S2, adding 2 parts by weight of BN and 0.2 parts by weight of hexadecyltrimethylammonium bromide to 20 parts by weight of deionized water, stirring thoroughly and then adding MWCNT, the mass ratio of BN to MWCNT is 2:1, after being evenly dispersed, adding 2 parts by weight of CNF, stirring overnight and then adding 3 parts by weight of silane hydrolysis solution, stirring to obtain a mixed solution;

[0035] S3, place the copper block in liquid nitrogen in a -100℃ freeze dryer, place the polytetrafluoroethylene mold on the copper block, pour the mixed liquid into the mold and cover the bottom of the mold, after it is completely frozen, continue to add the mixed liquid to cover the formed frozen layer, repeat several times until the frozen layer reaches 3mm, then place it in the freeze dryer for 48h, sinter at 700℃ for 5h, and obtain the 3DBN / MWCNT aerogel ceramic skeleton.

[0036] S4. Take 50 parts by weight of epoxy resin, 45 parts by weight of curing agent, 3 parts by weight of curing accelerator, and 2.3 parts by weight of flame retardant, and mix them to obtain epoxy resin curing component; after stirring the epoxy resin curing component (EP) evenly at 60°C, immerse it into the 3DBN / MWCNT aerogel ceramic skeleton under vacuum assistance, and then place it at 150°C for high temperature curing for 2 hours to obtain BN / MWCNT / EP composite material 1.

[0037] According to the test, the typical value of electromagnetic shielding effectiveness of BN / MWCNT / EP composite material 1 is up to 77dB, the absorption rate is over 50%, and the typical value of thermal conductivity can reach 0.6W / (m·K).

[0038] Example 2

[0039] This embodiment provides a method for preparing a ceramic skeleton epoxy composite material with high electromagnetic shielding absorption and thermal conductivity, which specifically includes the following steps:

[0040] S1, 2.5 ml of methyltrimethoxysilane and 2.5 ml of deionized water were mixed in equal volumes, and then 0.5 ml of HCl solution (10 vol%) was added, and the mixture was stirred in an ice bath for hydrolysis for 0.5 h to obtain a silane hydrolysis solution;

[0041] S2, adding 5 parts by weight of BN and 0.2 parts by weight of hexadecyltrimethylammonium bromide to 20 parts by weight of deionized water, stirring thoroughly and then adding MWCNT, the mass ratio of BN to MWCNT is 5:1, after being evenly dispersed, adding 2 parts by weight of CNF, stirring overnight and then adding 3 parts by weight of silane hydrolysis solution, stirring to obtain a mixed solution;

[0042] S3, place the copper block in liquid nitrogen in a -150℃ freeze dryer, place the polytetrafluoroethylene mold on the copper block, pour the mixed liquid into the mold to cover the bottom of the mold, and after it is completely frozen, continue to add the mixed liquid to cover the formed frozen layer, repeat several times until the frozen layer reaches 3mm, then place it in the freeze dryer for 48h, and sinter at 700℃ for 5h to obtain a 3DBN / MWCNT aerogel ceramic skeleton;

[0043] S4. Take 50 parts by weight of epoxy resin, 45 parts by weight of curing agent, 3 parts by weight of curing accelerator, and 2.3 parts by weight of flame retardant, and mix them to obtain epoxy resin curing component; after stirring the epoxy resin curing component (EP) evenly at 60°C, immerse it into the 3DBN / MWCNT aerogel ceramic skeleton under vacuum assistance, and then place it at 150°C for high temperature curing for 2 hours to obtain BN / MWCNT / EP composite material 2.

[0044] According to the test, the typical value of electromagnetic shielding effectiveness of BN / MWCNT / EP composite material 2 is up to 60dB, the absorption rate is over 50%, and the typical value of thermal conductivity can reach 1.5W / (m·K).

[0045] Example 3

[0046] This embodiment provides a method for preparing a ceramic skeleton epoxy composite material with high electromagnetic shielding absorption and thermal conductivity, which specifically includes the following steps:

[0047] S1, 2.5 ml of methyltrimethoxysilane and 2.5 ml of deionized water were mixed in equal volumes, and then 0.5 ml of HCl solution (10 vol%) was added, and the mixture was placed in an ice bath and stirred for hydrolysis for 0.5 h.

[0048] S2, adding 20 parts by weight of BN and 0.2 parts by weight of hexadecyltrimethylammonium bromide to 20 parts by weight of deionized water, stirring thoroughly and then adding MWCNT, the mass ratio of BN to MWCNT is 20:3, after being evenly dispersed, adding 2 parts by weight of CNF, stirring overnight and then adding 3 parts by weight of silane hydrolysis solution, stirring to obtain a mixed solution;

[0049] S3, place the copper block in liquid nitrogen in a -50℃ freeze dryer, place the polytetrafluoroethylene mold on the copper block, pour the mixed liquid into the mold to cover the bottom of the mold, and after it is completely frozen, continue to add the mixed liquid to cover the formed frozen layer, repeat several times until the frozen layer reaches 3mm, then place it in the freeze dryer for 48h, and sinter at 700℃ for 5h to obtain a 3DBN / MWCNT aerogel ceramic skeleton;

[0050] S4. Take 50 parts by weight of epoxy resin, 45 parts by weight of curing agent, 3 parts by weight of curing accelerator, and 2.3 parts by weight of flame retardant, and mix them to obtain epoxy resin curing component; after stirring the epoxy resin curing component (EP) evenly at 60°C, immerse it into 3DBN / MWCNT aerogel ceramic skeleton under vacuum assistance, and then place it at 150°C for high temperature curing for 2 hours to obtain BN / MWCNT / EP composite material 3.

[0051] According to the test, the typical value of electromagnetic shielding effectiveness of BN / MWCNT / EP composite material 3 is up to 15dB, the absorption rate is over 50%, and the typical value of thermal conductivity can reach 1.0W / (m·K).

[0052] Figure 1 The scanning images of the carbonized 3DBN / MWCNT aerogel ceramic skeleton obtained in step S3 of Example 2 of the present invention at different magnifications are 300 and 15000 times respectively. Figure 1 It can be seen that the skeleton in the figure has a good orientation. It is composed of a layer structure and is the main load-bearing structure. The MWCNT in the skeleton is intertwined like silk threads to build the entire plane, which greatly increases the mechanical properties of the overall material. At the same time, MWCNT connects adjacent BNs together and builds a bridge between BNs. Under the extrusion force of ice crystal growth, BNs are entangled by MWCNTs and overlap each other to form a heat conduction path. At the same time, MWCNT forms a conductive path and absorbs the dielectric loss caused by multiple reflections of electromagnetic waves.

[0053] Figure 2 is a scanning image of the BN / MWCNT / EP composite material obtained in step S4 of Example 2 of the present invention at different magnifications.Figure 2 It can be seen that after the epoxy resin curing component is immersed in the 3D ceramic skeleton, with the overall upward condition of the ceramic skeleton, the internal skeleton presents a wavy shape. These waves are meandering, providing sites for multiple reflections of electromagnetic waves and effectively increasing the absorption capacity. The orderliness of the skeleton basically remains unchanged, and there are no obvious voids at the boundaries between epoxy, MWCNT, and BN, indicating that the ceramic skeleton prepared by this method has good interfacial bonding with the matrix. From the in-plane view of the skeleton sheet, it can be seen that BN in the skeleton overlaps with each other under the action of adjacent MWCNT, forming a heat conduction path. At the same time, the dense MWCNT also constitutes an electrical conduction network.

[0054] Those skilled in the art should understand that the above are only several specific embodiments of the present invention, rather than all embodiments. It should be pointed out that many modifications and improvements can be made by those of ordinary skill in the art. All modifications or improvements that do not exceed the scope described in the claims shall be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a highly absorbing electromagnetic shielding and thermally conductive epoxy composite material, It is characterized in that The steps include: S1, a trimethoxy silane coupling agent and deionized water are mixed in equal volumes, and then a 10 vol% HCl solution is added, wherein the volume ratio of the trimethoxy silane coupling agent to the HCl solution is 5:1, and then placed in an ice bath and stirred for hydrolysis for 0.1-5h to obtain a silane hydrolysis solution; S2, add 0.5-10 parts by weight of boron nitride (BN) and 0.05-5 parts by weight of a surfactant to 10-60 parts by weight of deionized water, stir well, add multi-walled carbon nanotubes (MWCNT), the mass ratio of BN to MWCNT is 1:1-20:3, after being evenly dispersed, add 1-5 parts by weight of carbon nanofibers (CNF), and then add 0.4-3 parts by weight of a silane hydrolysis solution, and stir to obtain a mixed solution; S3. Pour the mixed solution into the mold under the temperature condition of -196-0°C and cover the bottom of the mold. After it is completely frozen, continue to add the mixed solution to cover the formed frozen layer, repeat several times until the frozen layer reaches 2-3mm, freeze-dry the frozen layer, and then sinter it at 300-1000°C for 1-10h to obtain a 3D BN / MWCNT aerogel ceramic skeleton. S4. After stirring the epoxy resin curing component at 20-90°C, immerse it into the 3DBN / MWCNT aerogel ceramic skeleton under vacuum assistance, and then thermally cure it to obtain a BN / MWCNT / EP composite material; the components of the epoxy resin curing component are as follows: 50-100 parts by weight of epoxy resin, 40-100 parts by weight of curing agent, 1-10 parts by weight of curing accelerator, and 2-5.25 parts by weight of flame retardant.

2. The method for preparing the highly absorbing electromagnetic shielding and thermally conductive epoxy composite material according to claim 1, It is characterized in that The trimethoxy silane coupling agent described in step S1 is one or a combination of two or more of aminopropyltrimethoxysilane (APTES), methoxytrimethoxysilane (MTMS), octyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

3. The method for preparing the highly absorbing electromagnetic shielding and thermally conductive epoxy composite material according to claim 1, It is characterized in that The surfactant described in step S2 is one or a combination of two or more of polydiallyldimethylammonium chloride (PDDA), cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, ammonium dodecyl sulfate, and dodecylbenzene sulfonic acid.

4. The method for preparing the highly absorbing electromagnetic shielding and thermally conductive epoxy composite material according to claim 1, It is characterized in that The particle size of the boron nitride (BN) in step S2 is 0.1-100 μm.

5. The method for preparing the highly absorbing electromagnetic shielding and thermally conductive epoxy composite material according to claim 1, It is characterized in that The specific operation of thermal curing in step S4 is as follows: The BN / MWCNT aerogel ceramic framework immersed in the epoxy resin curing component is placed at 90 - 200 °C for high-temperature curing for 1 - 9 h.

6. The preparation method of the highly absorbent electromagnetic shielding and heat-conducting epoxy composite material according to claim 1, wherein, the epoxy resin is one or a combination of two or more of bisphenol A side-chain type epoxy resin, methyl-substituted divinyl cyclohexene dioxide epoxy resin, and triglycidyl isocyanurate epoxy resin; or the curing agent is one or a combination of two of methylhexahydrophthalic anhydride and triethylenetetramine.

7. The preparation method of the highly absorbent electromagnetic shielding and heat-conducting epoxy composite material according to claim 1, wherein, the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol, and the flame retardant is a phosphorus-based flame retardant.

8. A highly absorbent electromagnetic shielding and heat-conducting epoxy composite material prepared by the preparation method according to any one of claims 1 - 7.

9. Use of the highly absorbent electromagnetic shielding and heat-conducting epoxy composite material according to claim 8 in the field of semiconductor packaging.

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