CN112876848A - Graphene oxide aerogel-based electromagnetic shielding polymer composite material with electricity and heat conduction double-network structure and preparation method thereof - Google Patents
Graphene oxide aerogel-based electromagnetic shielding polymer composite material with electricity and heat conduction double-network structure and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a graphene functional composite material, in particular to a graphene oxide aerogel-based electromagnetic shielding polymer composite material with an electric conduction-heat conduction double-network structure and a preparation method thereof, which solve the technical problems in the background art and comprise high-electric-conduction three-dimensional graphene aerogel, wherein liquid silicon rubber/boron nitride filler is filled in the high-electric-conduction three-dimensional graphene aerogel through a blending pouring process. The preparation method comprises the steps of carrying out freeze drying and high-temperature heat treatment on a graphene oxide solution to obtain the high-conductivity three-dimensional graphene aerogel; and uniformly blending boron nitride and silicon rubber, and filling the mixture into the high-conductivity three-dimensional graphene aerogel to obtain the graphene oxide aerogel-based electromagnetic shielding polymer composite material. According to the invention, the high-conductivity graphene and the high-thermal-conductivity but insulating boron nitride are successfully compounded, the respective advantages of the two-component filler are effectively exerted, and the application targets of high thermal conductivity and high shielding performance of the composite material can be realized under the condition of ensuring that the electromagnetic shielding effectiveness of the material is not reduced.
Description
Technical Field
The invention belongs to the technical field of graphene functional composite materials, and relates to an electromagnetic shielding polymer composite material, in particular to a graphene oxide aerogel-based electromagnetic shielding polymer composite material with a conductive-heat conductive double-network structure and a preparation method thereof.
Background
With the rapid development of high-power electronic equipment and electronic communication technologies such as 5G mobile network communication technology, increasingly complex electromagnetic radiation becomes a potential factor influencing equipment precision and threatening human health. Therefore, the development of high performance electromagnetic interference and shielding materials is an urgent need to meet the increasing electromagnetic radiation protection requirements. Based on the Schelkunoff electromagnetic wave interface conduction theory [ thomshin, j.m., et al.mater.sci.eng.: r.74(2013) 211-. Therefore, the highly conductive composite film [ Xu, y., et al chem.eng.j.360(2019) 1427-.
As integrated high-power electronic devices enter people's lives comprehensively, the heat dissipation problem of instruments is also concerned by people, but polymer matrixes of electromagnetic shielding composite materials are poor in heat conduction performance, so that the composite materials with high-efficiency electromagnetic shielding performance cannot meet the protection requirement of high-power instruments, and the multi-interface structure of electromagnetic wave reflection can cause more scattering in phonon conduction, so that heat is accumulated in the instruments and the composite materials, the normal work and the service life of the instruments are affected, and therefore, the development of the high-efficiency electromagnetic shielding polymer composite materials with the heat conduction function is very important. However, the construction of the conductive network greatly affects the heat-conducting performance of the heat-conducting network, and the perfection of the heat-conducting network blocks the communication of the conductive network, so that the composite material cannot obtain high-efficiency shielding effectiveness. Therefore, effective construction of a dual network of electrical conduction and insulating thermal conduction in a material matrix is still a key problem to be solved by the thermal electromagnetic shielding material.
Disclosure of Invention
The invention aims to solve the technical problem of effectively constructing a double electric conduction and insulating and heat conduction network in a composite material, and provides a graphene oxide aerogel-based electromagnetic shielding polymer composite material with an electric conduction-heat conduction double network structure and a preparation method thereof.
The technical means for solving the technical problems of the invention is as follows: the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electricity and heat conduction double-network structure comprises high-electricity-conduction three-dimensional graphene aerogel, wherein liquid silicon rubber/boron nitride filler is filled in the high-electricity-conduction three-dimensional graphene aerogel through a blending pouring process, and the high-electricity-conduction three-dimensional graphene aerogel and the boron nitride filler generate a composite synergistic double-network structure. The high-conductivity three-dimensional graphene aerogel is used as an effective medium of the conductive framework for electromagnetic wave attenuation and phonon transmission, and the heat-conducting boron nitride is filled in the composite material and is used as a channel for phonon access transmission, so that the heat-conducting property of the composite material is ensured. The electromagnetic shielding effectiveness of the heat-conducting electromagnetic shielding composite material can reach 40.1dB, and the heat conductivity coefficient can reach 0.73Wm-1K-1。
Preferably, the content of graphene in the composite material is 0.1wt% -0.4 wt%, and the content of boron nitride in the composite material is 10wt% -20 wt%.
The invention also provides a preparation method of the graphene oxide aerogel-based electromagnetic shielding polymer composite material based on the electric conduction-heat conduction double-network structure, which is used for solving the technical problem. The preparation method of the composite material successfully compounds the high-conductivity graphene and the high-conductivity but insulating boron nitride by using the idea of prefabricating the conductive network, and can effectively exert the respective advantages of the two-component filler. Electromagnetic waves are captured to the maximum extent through the three-dimensional network structure, so that the electromagnetic waves enter three-dimensional structures of the high-conductivity three-dimensional graphene aerogel to be repeatedly subjected to reflection loss, and the high efficiency of the shielding efficiency of the composite material is ensured; on the other hand, the three-dimensional conductive network enables the high-thermal-conductivity boron nitride to be connected more effectively in a limited space through the volume limiting effect, the high efficiency of the thermal conductivity of the composite material is ensured, and finally the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the thermal conductivity function is obtained.
Preferably, the specific preparation method of the highly conductive three-dimensional graphene aerogel comprises the following steps: weighing a certain amount of graphene oxide aqueous dispersion, and ultrasonically dispersing for a certain time; then adding a certain amount of hydroxymethyl cellulose into the graphene oxide dispersion liquid, mechanically stirring until the hydroxymethyl cellulose is completely dissolved, pouring the mixed liquid into a mold, placing the mold filled with the mixed liquid into liquid nitrogen for rapid freezing and shaping, and obtaining hydroxymethyl cellulose/graphene oxide foam by a vacuum freeze drying method; putting the hydroxymethyl cellulose/graphene oxide foam into a tubular furnace, heating to 1000 ℃ at a heating rate of 10 ℃/min in a nitrogen atmosphere, keeping for 2 hours, carbonizing the hydroxymethyl cellulose/graphene oxide foam at a high temperature, and reducing the graphene oxide at a high temperature to finally obtain the high-conductivity three-dimensional graphene aerogel. The preparation method comprises the steps of preparing the high-conductivity three-dimensional graphene aerogel by using a freeze drying and high-temperature heat treatment method, and filling silicon rubber/boron nitride into a three-dimensional conductive network of the high-conductivity three-dimensional graphene aerogel by using a co-mixing pouring method. Electromagnetic waves can be captured to the maximum extent through the hydroxymethyl cellulose/graphene oxide foam, so that the electromagnetic waves are repeatedly reflected and lost between cell walls after entering cells, and the high efficiency of the shielding efficiency of the composite material is ensured.
Preferably, the liquid silicone rubber adopts bi-component RTV silica gel, and the bi-component RTV silica gel comprises a component A and a component B; the specific operation of uniformly blending the boron nitride and the liquid silicone rubber is as follows: firstly, ball milling boron nitride particles for 24 hours; then blending boron nitride with the component A of the double-component RTV silica gel, ultrasonically dispersing and stirring the component A for 10min, adding the component B of the double-component RTV silica gel, stirring, and placing the mixture in a vacuum oven for defoaming to obtain the uniformly dispersed silicon rubber/boron nitride latex. The A component and the B component of the double-component RTV silica gel are the existing mature products.
The invention has the beneficial effects that: the high-conductivity three-dimensional graphene aerogel is used as an effective medium of the conductive framework for electromagnetic wave attenuation and phonon transmission, and the heat-conducting boron nitride is filled in the composite material and is used as a channel for leading phonons to the transmission, so that the heat-conducting property of the composite material is ensured; according to the preparation method of the composite material, the idea of prefabricating the conductive network is utilized, the high-conductivity three-dimensional graphene aerogel is prepared by a freeze drying and high-temperature heat treatment method, and the liquid silicon rubber/boron nitride is filled into the conductive network with the three-dimensional structure of the high-conductivity three-dimensional graphene aerogel by a co-mixing pouring method, so that on one hand, electromagnetic waves are captured to the maximum extent through the three-dimensional network structure, the electromagnetic waves enter the three-dimensional structure of the high-conductivity three-dimensional graphene aerogel and are repeatedly subjected to reflection loss, and the high efficiency of the shielding efficiency of the composite material is ensured; on the other hand, the three-dimensional conductive network enables the high-thermal-conductivity boron nitride to be connected more effectively in a limited space through the volume limiting effect, the high efficiency of the thermal conductivity of the composite material is ensured, and finally the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the thermal conductivity function is obtained.
Drawings
FIG. 1 shows the density of 1.8X 10-3g/cm3Scanning electron microscope images of the graphene aerogel.
FIG. 2 shows the density of 3.9X 10-3g/cm3Scanning electron microscope images of the graphene aerogel.
FIG. 3 shows the density of 5.6X 10-3g/cm3Scanning electron microscope images of the graphene aerogel.
Fig. 4 is a scanning electron micrograph of hexagonal boron nitride particles.
Fig. 5 is a cross-sectional scanning electron microscope picture of the graphene oxide aerogel-based electromagnetic shielding polymer composite material of the present invention.
Fig. 6 is a partially enlarged view of fig. 5.
Fig. 7 is an electromagnetic shielding performance graph of the graphene oxide aerogel-based electromagnetic shielding polymer composite according to various embodiments of the present invention.
Fig. 8 is a schematic thermal conductivity diagram of the graphene oxide aerogel-based electromagnetic shielding polymer composite according to various embodiments of the present invention.
Detailed Description
Referring to fig. 1 to 8, the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electric and thermal conduction double-network structure and the preparation method thereof according to the present invention will be described in detail.
Example 1: the preparation method of the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electricity and heat conduction double-network structure comprises the following steps:
step one, preparing a high-conductivity three-dimensional graphene aerogel, which comprises the following steps:
weighing 10mL of graphene oxide dispersion liquid (20mg of graphene oxide), and carrying out ultrasonic dispersion for 30 min; adding 0.1g of hydroxymethyl cellulose into the graphene oxide dispersion liquid, mechanically stirring until the hydroxymethyl cellulose is completely dissolved, pouring the mixed liquid into a mold, and filling the mixturePlacing the liquid-mixing mould on a cooling table immersed in liquid nitrogen, enabling ice crystals to grow from bottom to top by utilizing temperature gradient, and after the mixed liquid is frozen and shaped quickly, obtaining hydroxymethyl cellulose/graphene oxide foam by utilizing a freeze dryer by adopting a vacuum freeze drying method; putting the hydroxymethyl cellulose/graphene oxide foam into a tube furnace, heating the tube furnace to 1000 ℃ at a heating rate of 10 ℃/min under a nitrogen atmosphere and keeping the temperature for 2 hours, and carrying out high-temperature carbonization and graphene reduction treatment on the hydroxymethyl cellulose/graphene oxide foam to obtain the high-conductivity three-dimensional graphene aerogel, wherein the density of the high-conductivity three-dimensional graphene aerogel is 1.8 multiplied by 10-3g/cm3；
Step two, treating boron nitride:
the boron nitride particles are ball-milled for 24 hours to reduce the number of the sheet layers and the sheet diameter, and the finally obtained boron nitride has the average sheet diameter of about 1 mu m and the density of 2.27g/cm3In-plane thermal conductivity of 600Wm-1K-1；
Step three, preparing the silicon rubber/boron nitride latex:
blending 1g of boron nitride prepared in the second step with 4.5g of component A of the bi-component RTV silica gel, ultrasonically dispersing and stirring for 10min, adding 4.5g of component B of the bi-component RTV silica gel, and stirring for 5min (the mass ratio of the component A to the component B is 1:1, and the density of the bi-component RTV silica gel is 1.1 g/cm)3) Placing the mixture in a vacuum oven for defoaming for 10min to obtain uniformly dispersed silicon rubber/boron nitride latex;
preparing a heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material;
pouring the silicon rubber/boron nitride latex prepared in the third step into a mold carrying the high-conductivity three-dimensional graphene aerogel prepared in the first step, filling and sealing the latex under the vacuum condition, heating to 80 ℃ after the latex is completely filled, and curing for 2 hours to obtain the heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material, wherein the thickness of the composite material is 2 mm.
The graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electric conduction-heat conduction double-network structure is finally prepared by the preparation method in the embodiment 1, and comprises high-electric conduction three-dimensional graphene aerogel, wherein the high-electric conduction three-dimensional graphene aerogel is filled with liquid silicon rubber/boron nitride filler by a co-mixing pouring process, and the high-electric conduction three-dimensional graphene aerogel and the boron nitride filler generate a composite synergistic double-network structure; the content of graphene in the composite material is 0.1wt%, and the content of boron nitride in the composite material is 10 wt%.
Example 2: the preparation method of the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electricity and heat conduction double-network structure comprises the following steps:
step one, preparing a high-conductivity three-dimensional graphene aerogel, which comprises the following steps:
weighing 10mL of graphene oxide dispersion liquid (40mg of graphene oxide), and carrying out ultrasonic dispersion for 30 min; adding 0.1g of hydroxymethyl cellulose into the graphene oxide dispersion liquid, mechanically stirring until the hydroxymethyl cellulose is completely dissolved, pouring the mixed liquid into a mold, placing the mold filled with the mixed liquid on a cold table immersed in liquid nitrogen, growing ice crystals from bottom to top by using a temperature gradient, and obtaining hydroxymethyl cellulose/graphene oxide foam by using a freeze dryer and a vacuum freeze drying method after the mixed liquid is rapidly frozen and shaped; putting the hydroxymethyl cellulose/graphene oxide foam into a tube furnace, heating the tube furnace to 1000 ℃ at a heating rate of 10 ℃/min under a nitrogen atmosphere and keeping the temperature for 2 hours, and carrying out high-temperature carbonization and graphene reduction treatment on the hydroxymethyl cellulose/graphene oxide foam to obtain the high-conductivity three-dimensional graphene aerogel, wherein the density of the high-conductivity three-dimensional graphene aerogel is 3.9 multiplied by 10-3g/cm3；
Step two, treating boron nitride:
the boron nitride particles are ball-milled for 24 hours to reduce the number of the sheet layers and the sheet diameter, and the finally obtained boron nitride has the average sheet diameter of about 1 mu m and the density of 2.27g/cm3In-plane thermal conductivity of 600Wm-1K-1；
Step three, preparing the silicon rubber/boron nitride latex:
blending 1g of boron nitride prepared in the second step with 4.5g of component A of the double-component RTV silica gel, ultrasonically dispersing and stirring for 10min, and then adding 4.5g of the double-componentStirring the component B of the RTV silica gel for 5min (the mass ratio of the component A to the component B is 1:1, and the density of the two-component RTV silica gel is 1.1g/cm3) Placing the mixture in a vacuum oven for defoaming for 10min to obtain uniformly dispersed silicon rubber/boron nitride latex;
preparing a heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material;
pouring the silicon rubber/boron nitride latex prepared in the third step into a mold carrying the high-conductivity three-dimensional graphene aerogel prepared in the first step, filling and sealing the latex under the vacuum condition, heating to 80 ℃ after the latex is completely filled, and curing for 2 hours to obtain the heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material, wherein the thickness of the composite material is 2 mm.
The graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electric conduction-heat conduction double-network structure is finally prepared by the preparation method in the embodiment 2, and comprises high-electric conduction three-dimensional graphene aerogel, wherein the high-electric conduction three-dimensional graphene aerogel is filled with liquid silicon rubber/boron nitride filler by a co-mixing pouring process, and the high-electric conduction three-dimensional graphene aerogel and the boron nitride filler generate a composite synergistic double-network structure; the content of graphene in the composite material is 0.2 wt%, and the content of boron nitride in the composite material is 10 wt%.
Example 3: the preparation method of the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electricity and heat conduction double-network structure comprises the following steps:
step one, preparing a high-conductivity three-dimensional graphene aerogel, which comprises the following steps:
weighing 10mL of graphene oxide dispersion liquid (60mg of graphene oxide), and carrying out ultrasonic dispersion for 30 min; adding 0.1g of hydroxymethyl cellulose into the graphene oxide dispersion liquid, mechanically stirring until the hydroxymethyl cellulose is completely dissolved, pouring the mixed liquid into a mold, placing the mold filled with the mixed liquid on a cold table immersed in liquid nitrogen, growing ice crystals from bottom to top by using a temperature gradient, and obtaining hydroxymethyl cellulose/graphene oxide foam by using a freeze dryer and a vacuum freeze drying method after the mixed liquid is rapidly frozen and shaped; placing the hydroxymethylcellulose/graphene oxide foam in a tube furnaceIn the method, a tube furnace is heated to 1000 ℃ at a heating rate of 10 ℃/min and kept for 2 hours under nitrogen atmosphere, and the hydroxymethyl cellulose/graphene oxide foam is carbonized at high temperature and reduced to reduce graphene oxide to obtain the high-conductivity three-dimensional graphene aerogel, wherein the density of the high-conductivity three-dimensional graphene aerogel is 5.6 multiplied by 10-3g/cm3；
Step two, treating boron nitride:
the boron nitride particles are ball-milled for 24 hours to reduce the number of the sheet layers and the sheet diameter, and the finally obtained boron nitride has the average sheet diameter of about 1 mu m and the density of 2.27g/cm3In-plane thermal conductivity of 600Wm-1K-1；
Step three, preparing the silicon rubber/boron nitride latex:
blending 1g of boron nitride prepared in the second step with 4.5g of component A of the bi-component RTV silica gel, ultrasonically dispersing and stirring for 10min, adding 4.5g of component B of the bi-component RTV silica gel, and stirring for 5min (the mass ratio of the component A to the component B is 1:1, and the density of the bi-component RTV silica gel is 1.1 g/cm)3) Placing the mixture in a vacuum oven for defoaming for 10min to obtain uniformly dispersed silicon rubber/boron nitride latex;
preparing a heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material;
pouring the silicon rubber/boron nitride latex prepared in the third step into a mold carrying the high-conductivity three-dimensional graphene aerogel prepared in the first step, filling and sealing the latex under the vacuum condition, heating to 80 ℃ after the latex is completely filled, and curing for 2 hours to obtain the heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material, wherein the thickness of the composite material is 2 mm.
The graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electric conduction-thermal conduction double-network structure is finally prepared by the preparation method in the embodiment 3, and comprises high-electric conduction three-dimensional graphene aerogel, wherein the high-electric conduction three-dimensional graphene aerogel is filled with liquid silicon rubber/boron nitride filler by a co-mixing pouring process, and the high-electric conduction three-dimensional graphene aerogel and the boron nitride filler generate a composite synergistic double-network structure; the content of graphene in the composite material is 0.4wt%, and the content of boron nitride in the composite material is 10 wt%.
Example 4: the preparation method of the graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electricity and heat conduction double-network structure comprises the following steps:
step one, preparing a high-conductivity three-dimensional graphene aerogel, which comprises the following steps:
weighing 10mL of graphene oxide dispersion liquid (60mg of graphene oxide), and carrying out ultrasonic dispersion for 30 min; adding 0.1g of hydroxymethyl cellulose into the graphene oxide dispersion liquid, mechanically stirring until the hydroxymethyl cellulose is completely dissolved, pouring the mixed liquid into a mold, placing the mold filled with the mixed liquid on a cold table immersed in liquid nitrogen, growing ice crystals from bottom to top by using a temperature gradient, and obtaining hydroxymethyl cellulose/graphene oxide foam by using a freeze dryer and a vacuum freeze drying method after the mixed liquid is rapidly frozen and shaped; putting the hydroxymethyl cellulose/graphene oxide foam into a tube furnace, heating the tube furnace to 1000 ℃ at a heating rate of 10 ℃/min under a nitrogen atmosphere and keeping the temperature for 2 hours, and carrying out high-temperature carbonization and graphene reduction treatment on the hydroxymethyl cellulose/graphene oxide foam to obtain the high-conductivity three-dimensional graphene aerogel, wherein the density of the high-conductivity three-dimensional graphene aerogel is 5.6 multiplied by 10-3g/cm3；
Step two, treating boron nitride:
the boron nitride particles are ball-milled for 24 hours to reduce the number of the sheet layers and the sheet diameter, and the finally obtained boron nitride has the average sheet diameter of about 1 mu m and the density of 2.27g/cm3In-plane thermal conductivity of 600Wm-1K-1；
Step three, preparing the silicon rubber/boron nitride latex:
blending 2g of boron nitride prepared in the second step with 4g of A component of the bi-component RTV silica gel, ultrasonically dispersing and stirring for 10min, adding 4g of B component of the bi-component RTV silica gel, and stirring for 5min (the mass ratio of the A component to the B component is 1:1, and the density of the bi-component RTV silica gel is 1.1 g/cm)3) Placing the mixture in a vacuum oven for defoaming for 10min to obtain uniformly dispersed silicon rubber/boron nitride latex;
preparing a heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material;
pouring the silicon rubber/boron nitride latex prepared in the third step into a mold carrying the high-conductivity three-dimensional graphene aerogel prepared in the first step, filling and sealing the latex under the vacuum condition, heating to 80 ℃ after the latex is completely filled, and curing for 2 hours to obtain the heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material, wherein the thickness of the composite material is 2 mm.
The graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electric conduction-thermal conduction double-network structure is finally prepared by the preparation method described in embodiment 4, and comprises a high-electric conduction three-dimensional graphene aerogel, wherein the high-electric conduction three-dimensional graphene aerogel is filled with a liquid silicone rubber/boron nitride filler by a co-mixing pouring process, and the high-electric conduction three-dimensional graphene aerogel and the boron nitride filler generate a composite synergistic double-network structure; the content of graphene in the composite material is 0.4wt%, and the content of boron nitride in the composite material is 20 wt%.
Comparative example 1: the preparation method of the pure liquid silicone rubber comprises the following steps:
weighing 5g of component A of the double-component RTV silica gel and 5g of component B of the double-component RTV silica gel, blending and stirring for 5min until the components are uniformly dispersed (the mass ratio of the component A to the component B is 1:1), pouring the components into a mold, placing the mold in a vacuum oven for defoaming for 10min, and heating to 80 ℃ to cure for 2h to obtain a pure silicon rubber material with the thickness of 2 mm.
Comparative example 2: the preparation method of the non-heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material comprises the following steps:
step one, preparing a high-conductivity three-dimensional graphene aerogel, which comprises the following steps:
weighing 10mL of graphene oxide dispersion liquid (60mg of graphene oxide), and carrying out ultrasonic dispersion for 30 min; adding 0.1g of hydroxymethyl cellulose into the graphene oxide dispersion liquid, mechanically stirring until the hydroxymethyl cellulose is completely dissolved, pouring the mixed liquid into a mold, placing the mold filled with the mixed liquid on a cold table immersed in liquid nitrogen, growing ice crystals from bottom to top by using a temperature gradient, and obtaining the hydroxymethyl cellulose/graphite oxide by using a freeze dryer and a vacuum freeze drying method after the mixed liquid is rapidly frozen and shapedAn olefinic foam; putting the hydroxymethyl cellulose/graphene oxide foam into a tube furnace, heating the tube furnace to 1000 ℃ at a heating rate of 10 ℃/min under a nitrogen atmosphere and keeping the temperature for 2 hours, and carrying out high-temperature carbonization and graphene reduction treatment on the hydroxymethyl cellulose/graphene oxide foam to obtain the high-conductivity three-dimensional graphene aerogel, wherein the density of the high-conductivity three-dimensional graphene aerogel is 5.6 multiplied by 10-3g/cm3；
Preparing a non-heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material;
weighing 5g of component A of the double-component RTV silica gel and 5g of component B of the double-component RTV silica gel, blending and stirring for 5min until the components are uniformly dispersed (the mass ratio of the component A to the component B is 1:1), and placing the components in a vacuum oven for defoaming for 10min to obtain uniform silicone rubber latex; pouring silicone rubber latex into a mold carrying the high-conductivity three-dimensional graphene aerogel prepared in the first step, filling and sealing the latex under the vacuum condition, heating to 80 ℃ after the latex is completely filled, and curing for 2 hours to obtain the non-heat-conducting graphene oxide aerogel-based electromagnetic shielding polymer composite material, wherein the thickness of the composite material is 2 mm.
Comparative example 3: the preparation method of the silicon rubber/boron nitride heat-conducting composite material comprises the following steps:
step one, treating boron nitride:
the boron nitride particles are ball-milled for 24 hours to reduce the number of the sheet layers and the sheet diameter, and the finally obtained boron nitride has the average sheet diameter of about 1 mu m and the density of 2.27g/cm3In-plane thermal conductivity of 600Wm-1K-1；
Step two, the preparation of the silicon rubber/boron nitride heat-conducting composite material comprises the following steps:
taking 1g of boron nitride obtained in the step one and 4.5g of A component of double-component RTV silica gel for blending, ultrasonically dispersing and stirring for 10min, adding 4.5g of B component of double-component RTV silica gel and stirring for 5min (the mass ratio of the A component to the B component is 1:1), and obtaining uniformly dispersed silicon rubber/boron nitride latex; pouring the silicon rubber/boron nitride latex into a mold, placing the mold in a vacuum oven for defoaming for 10min, and then heating to 80 ℃ for curing for 2h to obtain the silicon rubber/boron nitride heat-conducting composite material with the thickness of 2 mm.
Comparative example 4: the preparation method of the silicone rubber/boron nitride/graphene heat-conducting electromagnetic shielding composite material with the blended uniform structure comprises the following steps:
step one, the preparation of the thermal reduction graphene oxide powder comprises the following steps:
weighing 100mL of graphene oxide dispersion liquid (100mg of graphene oxide) and placing the graphene oxide dispersion liquid in a three-neck flask, heating the graphene oxide dispersion liquid in a water bath to 90 ℃, dropwise adding 7mL of hydrazine hydrate solution (80 wt%) into the graphene oxide dispersion liquid at the rate of 1mL/s, mechanically stirring the mixture for 4 hours under the temperature, washing the mixture for 5 times and 3 times respectively by using deionized water and ethanol by using a suction filtration method, and freeze-drying the mixture to obtain reduced graphene oxide powder; carrying out the heat treatment process in the first embodiment on the graphene oxide powder to obtain thermal reduction graphene oxide powder, wherein the electrical conductivity of the thermal reduction graphene oxide powder is 2.7S/cm;
step two, treating boron nitride:
the boron nitride particles are ball-milled for 24 hours to reduce the number of the sheet layers and the sheet diameter, the average sheet diameter of the processed boron nitride is about 1 mu m, and the density is 2.27g/cm3In-plane thermal conductivity of 600Wm-1K-1；
Step three: the preparation method of the silicon rubber/boron nitride/graphene heat-conducting electromagnetic shielding composite material comprises the following steps:
blending 1g of boron nitride obtained in the second step, 60mg of thermal reduction graphene oxide powder obtained in the first step and 4.5g of component A of double-component RTV silica gel, ultrasonically dispersing and stirring for 10min, adding 4.5g of component B of the double-component RTV silica gel, and stirring for 5min (the mass ratio of the component A to the component B is 1:1), so as to obtain uniformly dispersed silicon rubber/boron nitride/graphene latex; pouring the silicone rubber/boron nitride/graphene latex into a mold, placing the mold in a vacuum oven for defoaming for 10min, and then heating to 80 ℃ for curing for 2h to obtain the silicone rubber/boron nitride/graphene heat-conducting electromagnetic shielding composite material with the thickness of 2 mm.
TABLE 1 electromagnetic shielding effectiveness and thermal conductivity of the composites obtained in the four examples and the four comparative examples
As can be seen from table 1, in the thermally conductive graphene oxide aerogel-based electromagnetic shielding polymer composites of examples 1 to 4, the electromagnetic shielding effectiveness and the thermal conductivity of the composites gradually increase with the increase of the graphene content. The heat-conducting property of the composite material is remarkably improved along with the addition of the high-heat-conducting boron nitride filler. Compared with the electromagnetic shielding composite material formed by a uniform blending structure in a comparative example, the graphene oxide aerogel-based heat-conducting electromagnetic shielding polymer composite material prepared by the preparation method disclosed by the invention can endow the composite material with high-efficiency controllable shielding effectiveness on the basis of ensuring the heat-conducting performance.
As can be seen from fig. 1 to 3, graphene sheets are overlapped with each other to form a three-conductive network structure through freeze-drying and high-temperature reduction, and the density of fig. 1 is 1.8 × 10-3g/cm3Density of 3.9X 10 in FIG. 2-3g/cm3Density of 5.6X 10 in FIG. 3-3g/cm3Furthermore, as can be seen from fig. 1 to 3, the implementation of the prefabricated conductive networks with different densities ensures that the shielding performance of the composite material is highly adjustable.
As can be seen from FIG. 4, the average particle size of hexagonal boron nitride is about 1 μm after 24h ball milling process, which is beneficial to ensuring the full encapsulation of the composite material.
As can be seen from fig. 5 and 6, the silicon rubber/boron nitride matrix is densely filled in the three-dimensional graphene network, the conductive path of the prefabricated conductive network is not damaged, and the heat-conducting network is successfully constructed in the composite material by uniformly dispersing the boron nitride filler on the premise of not affecting the conductivity of the material.
As can be seen from fig. 7 and 8, the electromagnetic shielding effectiveness of the composite material depends on the density of the preformed network, i.e. the electrical conductivity of the preformed conductive network; the addition of the insulating and heat-conducting boron nitride filler does not damage the conductive network, and on the contrary, the introduction of the insulating and heat-conducting boron nitride brings more electronic polarization interfaces, which is beneficial to the attenuation of electromagnetic waves. In addition, the boron nitride and the prefabricated three-dimensional graphene network become the interior of the composite materialThe thermal conductivity of the composite material can be increased along with the increase of the density of the prefabricated graphene network, the thermal conductivity of the composite material is greatly improved by adding the boron nitride thermal conductive filler, and the high-efficiency controllability and the optimization of the thermal conductivity of the shielding effectiveness of the composite material are realized, so that the analysis of fig. 7 and 8 can obtain that the composite material prepared in the embodiment 4 achieves the optimal values (40.1 dB and 0.73W/m respectively) of the electromagnetic shielding performance and the thermal conductivity under the filling of 0.4wt% of graphene and 20wt% of hBN-1K-1)。
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. The graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electricity and heat conduction double-network structure is characterized by comprising high-electricity-conduction three-dimensional graphene aerogel, wherein liquid silicon rubber/boron nitride filler is filled in the high-electricity-conduction three-dimensional graphene aerogel through a blending pouring process, and the high-electricity-conduction three-dimensional graphene aerogel and the boron nitride filler generate a composite synergistic double-network structure.
2. The graphene oxide aerogel-based electromagnetic shielding polymer composite material with the electric and thermal conduction double-network structure as claimed in claim 1, wherein the content of graphene in the composite material is 0.1wt% to 0.4wt%, and the content of boron nitride in the composite material is 10wt% to 20 wt%.
3. The preparation method of the graphene oxide aerogel-based electromagnetic shielding polymer composite material based on the electric conduction-heat conduction double-network structure as claimed in claim 1 or 2, characterized in that after the boron nitride and the liquid silicon rubber are uniformly blended, the high-electric conduction three-dimensional graphene aerogel is filled by adopting a casting and curing method to obtain the graphene oxide aerogel-based electromagnetic shielding polymer composite material.
4. The preparation method of claim 3, wherein the specific preparation method of the highly conductive three-dimensional graphene aerogel is as follows: weighing graphene oxide aqueous dispersion, and performing ultrasonic dispersion; then adding hydroxymethyl cellulose into the graphene oxide dispersion liquid, mechanically stirring until the hydroxymethyl cellulose is completely dissolved, pouring the mixed liquid into a mold, placing the mold filled with the mixed liquid into liquid nitrogen for rapid freezing and shaping, and obtaining hydroxymethyl cellulose/graphene oxide foam by a vacuum freeze drying method; putting the hydroxymethyl cellulose/graphene oxide foam into a tubular furnace, heating to 1000 ℃ at a heating rate of 10 ℃/min in a nitrogen atmosphere, keeping for 2 hours, carbonizing the hydroxymethyl cellulose/graphene oxide foam at a high temperature, and reducing the graphene oxide at a high temperature to finally obtain the high-conductivity three-dimensional graphene aerogel.
5. The method according to claim 4, wherein the freeze-dried mixture is vacuum freeze-dried by a freeze-dryer.
6. The method of claim 4, wherein the rapid freezing and shaping operations of the mold filled with the mixture in liquid nitrogen are: the mould with the mixed liquid is placed on a cold table immersed in liquid nitrogen, and ice crystals grow from bottom to top by utilizing the temperature gradient.
7. The production method according to claim 3, wherein the liquid silicone rubber is a two-component RTV silicone rubber comprising an A component and a B component; the specific operation of uniformly blending the boron nitride and the liquid silicone rubber is as follows: firstly, ball milling boron nitride particles for 24 hours; then blending boron nitride with the component A of the double-component RTV silica gel, ultrasonically dispersing and stirring the component A for 10min, adding the component B of the double-component RTV silica gel, stirring, and placing the mixture in a vacuum oven for defoaming to obtain the uniformly dispersed silicon rubber/boron nitride latex.
8. The preparation method of claim 7, wherein the prepared silicone rubber/boron nitride latex is poured into a mold with the highly conductive three-dimensional graphene aerogel, the latex is encapsulated under vacuum conditions, and after the latex is completely filled, the temperature is raised to 80 ℃ for curing for 2 hours, so as to obtain the graphene oxide aerogel-based electromagnetic shielding polymer composite material.
9. The process according to claim 7, wherein the bicomponent RTV silica gel has a density of 1.1g/cm3The mass ratio of the component A to the component B is 1: 1.
10. The method according to claim 7, wherein the boron nitride particles are ball-milled to have an average particle size of 1 μm and a density of 2.27g/cm3In-plane thermal conductivity of 600Wm-1K-1。
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113825379A (en) * | 2021-09-29 | 2021-12-21 | 四川大学 | Magnetic MOF @ graphene aerogel microsphere and preparation method and application thereof |
| CN114085530A (en) * | 2021-11-10 | 2022-02-25 | 华东理工大学 | Low-thermal-resistance high-thermal-conductivity graphene silicone rubber composite material and preparation method thereof |
| CN114517014A (en) * | 2020-11-18 | 2022-05-20 | 洛阳尖端技术研究院 | Heat-conducting shielding rubber, preparation method thereof and electronic equipment containing heat-conducting shielding rubber |
| CN114891351A (en) * | 2022-05-09 | 2022-08-12 | 华南理工大学 | Heat-conducting wave-absorbing silicone rubber composite material and preparation method and application thereof |
| CN115260995A (en) * | 2022-07-22 | 2022-11-01 | 中国地质大学（武汉） | Double-network heat-conducting porous aerogel energy storage material and preparation method and application thereof |
| CN115322521A (en) * | 2022-08-08 | 2022-11-11 | 北京科技大学 | Preparation method of high-thermal-conductivity 3-3 type graphene/epoxy resin composite material |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20170036915A1 (en) * | 2015-08-06 | 2017-02-09 | Lawrence Livermore National Security, Llc | Highly crystalline 3d graphene |
| CN106433131A (en) * | 2015-08-05 | 2017-02-22 | 中国科学院宁波材料技术与工程研究所 | Graphene heat conduction silica gel and preparation method thereof |
| CN108165019A (en) * | 2018-02-01 | 2018-06-15 | 青岛科技大学 | A kind of electromagnetic shielding silicon rubber/graphene/carbon nano tube nanocomposite material and preparation method thereof |
| CN108165018A (en) * | 2018-02-01 | 2018-06-15 | 青岛科技大学 | A kind of electromagnetic shielding silicon rubber/graphene/nano silver wire nanocomposite and preparation method thereof |
| CN108913104A (en) * | 2018-06-27 | 2018-11-30 | 中国科学院宁波材料技术与工程研究所 | A kind of heat-conducting pad and preparation method thereof |
| CN109762204A (en) * | 2018-12-14 | 2019-05-17 | 中国科学院深圳先进技术研究院 | Three-dimensional structure boron nitride-graphene oxide hybrid material, preparation method and as filler heat-conductive composite material purposes |
-
2021
- 2021-01-18 CN CN202110062307.4A patent/CN112876848B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106433131A (en) * | 2015-08-05 | 2017-02-22 | 中国科学院宁波材料技术与工程研究所 | Graphene heat conduction silica gel and preparation method thereof |
| US20170036915A1 (en) * | 2015-08-06 | 2017-02-09 | Lawrence Livermore National Security, Llc | Highly crystalline 3d graphene |
| CN108165019A (en) * | 2018-02-01 | 2018-06-15 | 青岛科技大学 | A kind of electromagnetic shielding silicon rubber/graphene/carbon nano tube nanocomposite material and preparation method thereof |
| CN108165018A (en) * | 2018-02-01 | 2018-06-15 | 青岛科技大学 | A kind of electromagnetic shielding silicon rubber/graphene/nano silver wire nanocomposite and preparation method thereof |
| CN108913104A (en) * | 2018-06-27 | 2018-11-30 | 中国科学院宁波材料技术与工程研究所 | A kind of heat-conducting pad and preparation method thereof |
| CN109762204A (en) * | 2018-12-14 | 2019-05-17 | 中国科学院深圳先进技术研究院 | Three-dimensional structure boron nitride-graphene oxide hybrid material, preparation method and as filler heat-conductive composite material purposes |
Non-Patent Citations (2)
| Title |
|---|
| 文芳等: "石墨烯导热硅橡胶的研究进展", 《化工新型材料》 * |
| 董梦杰等: "导热橡胶研究进展", 《高分子通报》 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114517014A (en) * | 2020-11-18 | 2022-05-20 | 洛阳尖端技术研究院 | Heat-conducting shielding rubber, preparation method thereof and electronic equipment containing heat-conducting shielding rubber |
| CN113825379A (en) * | 2021-09-29 | 2021-12-21 | 四川大学 | Magnetic MOF @ graphene aerogel microsphere and preparation method and application thereof |
| CN114085530A (en) * | 2021-11-10 | 2022-02-25 | 华东理工大学 | Low-thermal-resistance high-thermal-conductivity graphene silicone rubber composite material and preparation method thereof |
| CN114891351A (en) * | 2022-05-09 | 2022-08-12 | 华南理工大学 | Heat-conducting wave-absorbing silicone rubber composite material and preparation method and application thereof |
| CN115260995A (en) * | 2022-07-22 | 2022-11-01 | 中国地质大学（武汉） | Double-network heat-conducting porous aerogel energy storage material and preparation method and application thereof |
| CN115322521A (en) * | 2022-08-08 | 2022-11-11 | 北京科技大学 | Preparation method of high-thermal-conductivity 3-3 type graphene/epoxy resin composite material |
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