An oriented carbon fiber filled organosilicon composite material and its preparation method and application

Abstract

The invention discloses a kind of oriented carbon fiber filled organosilicon composite material and its preparation method and application, belong to polymer-based thermal conductive interface material technical field, the preparation method of the present invention is:Carbon fiber is surface treated and oxidation treatment is obtained oxidized carbon fiber;Oxidized carbon fiber and phytic acid are added in water to obtain phytic acid modified carbon fiber;It is added in water, iron chloride and ferrous sulfate are added, iron ion is fixed on phytic acid modified carbon fiber surface, sodium hydroxide is added to obtain phytic acid ferroferric oxide modified carbon fiber;After vinyl silicone oil, hydrogenated silicone oil and catalyst are mixed, phytic acid ferroferric oxide modified carbon fiber is added, after homogenization treatment and deaeration treatment, phytic acid ferroferric oxide modified carbon fiber is made to be arranged along magnetic field direction orientation in an external magnetic field, solidified to obtain oriented carbon fiber filled organosilicon composite material.The present invention, by introducing phytic acid and ferroferric oxide, makes carbon fiber still have excellent thermal conductivity in the situation of low filling amount.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer-based thermal conductive interface materials, and more particularly to an oriented carbon fiber-filled organosilicon composite material, a preparation method thereof, and applications thereof. Background Art

[0002] With the increasing power density of modern micro-devices, microprocessors, LEDs and other electronic products, heat dissipation methods and efficiency are attracting more and more attention. As chip power continues to increase, minimizing device thermal resistance and improving heat dissipation efficiency are of great significance to ensuring the high performance and stability of microelectronic devices. Thermal conductive interface materials are used to connect two different materials in the entire heat flow path. They can effectively improve the heat conduction between the two solid interfaces, improve the thermal management level of electronic components, and play a key role in the field of thermal packaging. Thermal conductive interface materials are usually composite materials formed by using polymer materials as the matrix and filling a certain amount of thermal conductive fillers. Generally speaking, thermal conductive fillers mainly include three types of metals, ceramics and carbon materials, while polymer matrix materials are usually mostly silicone, rubber and resin materials.

[0003] The polymer matrix material primarily influences the preparation process and mechanical properties of thermally conductive interface materials, while the thermally conductive filler is the primary factor determining the thermal conductivity of thermally conductive interface materials. Generally speaking, by adding a thermally conductive filler of appropriate particle size and loading into the polymer matrix to reach the percolation threshold of the thermally conductive interface material, a relatively complete thermal conductivity path can be formed between the polymer matrix and the thermally conductive filler, significantly improving the thermal conductivity of the thermally conductive interface material. This method of directly adding thermally conductive fillers to the polymer matrix does not involve complex physical processes and chemical reactions, making the overall process safe and simple. However, to obtain thermally conductive interface materials with ideal thermal conductivity, researchers have primarily improved the thermal conductivity of polymer-based composites by adding thermally conductive fillers such as copper, aluminum, aluminum oxide, boron nitride, and graphene to silicone and epoxy resin polymer matrices. By simply physically blending, inorganic thermally conductive fillers are dispersed in the polymer matrix, resulting in polymer-based thermally conductive composites with certain thermal and mechanical properties. However, adding high loadings of thermally conductive fillers to the polymer matrix can reduce the deformation capacity of the thermally conductive interface material and make the thermally conductive composite susceptible to cracking. In addition, the random distribution of high-filling thermal conductive fillers in the polymer matrix will aggravate the phonon scattering and interface thermal resistance in the composite material, making it difficult to form an efficient thermal conduction path, which is not conducive to improving the thermal conductivity of the composite material. Summary of the Invention

[0004] In response to the above problems, the present invention provides an oriented carbon fiber filled silicone composite material and a preparation method thereof. The oriented carbon fiber filled silicone composite material prepared by the present invention introduces phytic acid and ferrosoferric oxide, so that the carbon fiber still has excellent thermal conductivity at a low filling amount.

[0005] The first object of the present invention is to provide a method for preparing an oriented carbon fiber filled organosilicon composite material, comprising the following steps: in an organic solvent, surface treating the carbon fiber to remove organic impurities, and then oxidizing the carbon fiber to obtain oxidized carbon fiber. The oxidized carbon fiber and phytic acid are added to water, and a complexation reaction occurs at 30°C to 50°C to obtain phytic acid modified carbon fiber; the phytic acid modified carbon fiber is added to water, and ferric chloride and ferrous sulfate are added at 50°C to 70°C, and the iron ions are fixed on the surface of the phytic acid modified carbon fiber through the chelation effect of phytic acid and iron ions, and sodium hydroxide is added to cause a coprecipitation reaction to obtain phytic acid-ferrosoferric oxide modified carbon fiber; for example, the reaction temperature of the complexation reaction is 30°C, 35°C, 40°C, 45°C, 50°C, etc. The temperature for adding ferric chloride and ferrous sulfate is 50°C, 55°C, 60°C, 65°C, 70°C, etc., but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0006] After vinyl silicone oil, hydrogenated silicone oil and catalyst are evenly mixed, phytic acid-ferroferric oxide modified carbon fibers are added, homogenized and degassed, and then the phytic acid-ferroferric oxide modified carbon fibers are oriented and arranged along the direction of the magnetic field in an external magnetic field, and then cured to obtain an oriented carbon fiber filled silicone composite material.

[0007] The present invention is in the preparation process, first surface-treated to carbon fiber, removes organic impurities remaining on the carbon fiber surface during the carbon fiber preparation process, and then performs oxidation treatment to obtain oxidized carbon fiber, introduces phytic acid on the oxidized carbon fiber surface, phytic acid is a phosphorus-containing organic acid with multiple phosphate groups, which enables it to react with the oxidized carbon fiber surface to obtain phytic acid-modified carbon fiber; then using phytic acid-modified carbon fiber as raw material, the iron ions are fixed to the carbon fiber surface by the chelation of phytic acid to metal ions, and then sodium hydroxide is added, and magnetic ferroferric oxide nanoparticles are deposited on the asphalt-based carbon fiber surface by the coprecipitation reaction of the iron ions. Phytic acid-ferroferric oxide modified carbon fiber is obtained; then driven by an external magnetic field, phytic acid-ferroferric oxide modified carbon fiber is oriented in an organosilicon composite material to obtain an oriented carbon fiber filled organosilicon composite material. The carbon fiber used in the present invention is asphalt-based carbon fiber, and asphalt-based carbon fiber has excellent thermal conductivity.

[0008] In a preferred embodiment of the present invention, the ratio of oxidized carbon fiber to phytic acid is 1g:7mg-8mg, and the reaction time of the complexation reaction is 24h-48h. For example, the ratio of oxidized carbon fiber to phytic acid is 1g:7mg, 1g:7.5mg, 1g:8mg, etc., and the reaction time of the complexation reaction is 24h, 30h, 36h, 42h, 48h, etc., but the above values ​​are not limited to the above values, and other values ​​not listed within the above range are also applicable.

[0009] In a preferred embodiment of the present invention, the mass ratio of phytic acid modified carbon fiber and ferric chloride is 10:3~4.5; for example, the mass ratio of phytic acid modified carbon fiber and ferric chloride is 10:3, 10:3.5, 10:4, 10:4.5, etc.; the mass ratio of phytic acid modified carbon fiber and ferrous sulfate is 10:1.5~4; for example, the mass ratio of phytic acid modified carbon fiber and ferrous sulfate is 10:1, 10:2, 10:3, 10:4, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are equally applicable.

[0010] In a preferred embodiment of the present invention, the mass ratio of the phytic acid modified carbon fiber to the sodium hydroxide is 1:0.2 to 0.5. For example, the mass ratio of the phytic acid modified carbon fiber to the sodium hydroxide is 1:0.2, 1:0.3, 1:0.4, 1:0.5, etc. The reaction time of the coprecipitation reaction is 1 hour to 3 hours. For example, the reaction time of the coprecipitation reaction is 1 hour, 2 hours, 3 hours, etc., but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0011] In a preferred embodiment of the present invention, the mass ratio of vinyl silicone oil to hydrogen-containing silicone oil is 100:2.5~4; for example, the mass ratio of vinyl silicone oil to hydrogen-containing silicone oil is 100:2.5, 100:3, 100:3.5, 100:4, etc.; the mass ratio of vinyl silicone oil to catalyst is 100:0.3~0.7, for example, the mass ratio of vinyl silicone oil to catalyst is 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are equally applicable.

[0012] In a preferred embodiment of the present invention, the addition amount of phytic acid-ferroferric oxide modified carbon fiber is 10% to 20% of the total mass of vinyl silicone oil and hydrogen-containing silicone oil. For example, the addition amount of phytic acid-ferroferric oxide modified carbon fiber is 10%, 12%, 14%, 16%, 18%, 20% of the total mass of vinyl silicone oil and hydrogen-containing silicone oil, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are equally applicable.

[0013] In a preferred embodiment of the present invention, the time of applying the external magnetic field is 1h~1.5h. For example, the time of applying the external magnetic field is 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, etc., but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0014] In a preferred embodiment of the present invention, the surface treatment is performed at 40°C to 60°C for 10 to 14 hours. For example, the surface treatment temperature is 40°C, 50°C, 60°C, etc., and the treatment time is 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, etc. The oxidation treatment is performed using a solution of nitric acid and sulfuric acid at 40°C to 60°C for 4-6 hours. For example, the oxidation treatment temperature is 40°C, 50°C, 60°C, etc., and the treatment time is 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, etc., but the above values ​​are not limited thereto, and other values ​​not listed within the above numerical ranges are also applicable.

[0015] The second object of the present invention is to provide an oriented carbon fiber filled organosilicon composite material prepared by the above preparation method.

[0016] The third object of the present invention is to provide the use of the above-mentioned oriented carbon fiber filled organosilicon composite material in the preparation of thermal conductive materials.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In the present invention, phytic acid is first grafted onto the surface of asphalt-based carbon fibers by the complexation of phytic acid, and then magnetic ferroferric oxide nanoparticles are deposited onto the surface of asphalt-based carbon fibers by the chelation of phytic acid to metal ions and the coprecipitation reaction of iron ions. Phytic acid, as a linking agent, can enhance the binding force between magnetic ferroferric oxide nanoparticles and asphalt-based carbon fibers and improve the stability of magnetic ferroferric oxide nanoparticles on the surface of asphalt-based carbon fibers. Asphalt-based carbon fibers modified with phytic acid and magnetic ferroferric oxide nanoparticles have magnetic responsiveness, and under the action of an external magnetic field, the modified asphalt-based carbon fibers are induced to be vertically oriented in an organosilicon matrix, and an oriented carbon fiber-filled organosilicon thermal conductive composite material is prepared at a low thermal conductive filler filling amount. The orientation direction of the carbon fibers in the organosilicon thermal conductive composite material is consistent with the direction of phonon transmission, forming an effective heat conduction path, which greatly improves the thermal conductivity of the organosilicon composite material. The present invention can orient the asphalt-based carbon fibers in the organosilicon matrix to form an efficient heat conduction path, thereby obtaining a high-performance heat conductive composite material at a low filling amount and maintaining the good flexibility and mechanical properties of the organosilicon composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a preparation flow chart of the present invention.

[0020] Figure 2 This is the hysteresis loop of the phytic acid-ferroferric oxide modified carbon fiber sample prepared in Example 2.

[0021] Figure 3 These are optical photographs of the phytic acid-ferroferric oxide modified carbon fiber sample prepared in Example 2 dispersed in water under conditions without a magnetic field and with a magnetic field, wherein a is an optical photograph of the phytic acid-ferroferric oxide modified carbon fiber sample under conditions without a magnetic field, and b is an optical photograph of the phytic acid-ferroferric oxide modified carbon fiber sample under conditions with a magnetic field.

[0022] Figure 4 Thermal conductivity diagram of different materials.

[0023] Figure 5 These are thermal images of different materials, where a is the thermal image and b is the time and temperature curve of different materials.

[0024] Figure 6 A graph showing the tensile strength of different materials.

[0025] Figure 7 Graph of elastic modulus for different materials.

[0026] Figure 8 The elongation at break diagram of different materials.

[0027] Figure 9 The Shore hardness diagram of different materials.

[0028] Figure 10 Volume resistivity diagram of different materials. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Modern electronic products are developing rapidly in the direction of miniaturization, integration and lightweight, and thermal management has become a key technical challenge. The development of thermal interface materials with high thermal conductivity is an effective strategy for electronic products to achieve efficient thermal management. Polymers are widely used as the matrix of thermal interface materials because of their light weight, easy processing, low cost and stable physical and chemical properties. Carbon fiber itself has high thermal conductivity, low cost, easy modification, and can effectively improve the thermal conductivity of polymer-based composites. However, simple physical mixing between polymers and carbon fibers often leads to more phonon scattering, which is not conducive to improving the thermal conductivity of composite materials. Moreover, usually carbon fiber needs to be filled in a high amount to improve the thermal conductivity of the composite material, but too high a filling amount of carbon fiber will reduce the flexibility and mechanical properties of the composite material. Therefore, how to make the thermal conductive filler form a good thermal conductive path at a low filling amount, thereby improving the thermal conductivity of the composite material, has become the key to the development of high-performance thermal interface materials. Based on this, the present invention provides a method for preparing an oriented carbon fiber filled silicone composite material, and the preparation flow chart is shown as follows. Figure 1 As shown, phytic acid acts as a connector between pitch-based carbon fibers and magnetic ferroferric oxide nanoparticles. Phytic acid can be modified onto the surface of pitch-based carbon fibers through complexation and, through chelation of metal ions, allows the magnetic ferroferric oxide nanoparticles to be more stably bound to the carbon fiber surface. This strengthens the binding force between the magnetic ferroferric oxide nanoparticles and the pitch-based carbon fibers, facilitating the directional orientation of the carbon fibers within the silicone matrix under an applied magnetic field. Phytic acid primarily provides binding sites for the deposition of magnetic ferroferric oxide nanoparticles on the pitch-based carbon fibers, securing them. This helps to improve the uniform distribution of the magnetic ferroferric oxide nanoparticles on the carbon fiber surface and prevents agglomeration of the magnetic ferroferric oxide nanoparticles, thereby reducing the thermal resistance between thermally conductive fillers and improving the thermal conductivity of the composite material.

[0031] The vinyl silicone oil used in the present invention is RH-Vi1323, the hydrogen-containing silicone oil is RH-H536, the size of the asphalt-based carbon fiber is 160-200 μm, and the diameter is 7-10 μm. The manufacturer purchased is Japan Deyan Carbon Fiber Co., Ltd.

[0032] Example 1

[0033] (1) 5 g of asphalt-based carbon fiber was dispersed in 60 mL of acetone. After reflux reaction at 40 ° C and normal pressure for 14 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 8 g of asphalt-based carbon fiber was added to 50 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 60 ° C for 8 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain oxidized carbon fiber for standby use.

[0034] (2) 5 g of the oxidized carbon fiber obtained in step (1) and 40 mg of phytic acid were completely dispersed in 100 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 24 h in a constant temperature water bath at 50 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0035] (3) Weigh 3 g of dried phytic acid modified carbon fiber and completely disperse it in 40 mL of deionized water. Then heat the mixture of phytic acid modified carbon fiber and water to 70 ° C, add 1.08 g of ferric chloride hexahydrate and 0.56 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 30 minutes, and then quickly add 0.8 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 1 hour and then stop the reaction. After the reaction product is allowed to stand for 1 hour, it is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0036] (4) After 80 g of vinyl silicone oil, 2 g of hydrogenated silicone oil, and 0.3 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 10 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm for 3 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 15 minutes, and then the carbon fiber and silicone mixture was placed in an external magnetic field for 1 hour. Finally, it was cured in a vacuum drying oven at 1000 ° C for 3 hours to obtain an oriented carbon fiber filled silicone composite material.

[0037] Example 2

[0038] (1) 10 g of asphalt-based carbon fiber was dispersed in 80 mL of acetone. After reflux reaction at 50 ° C and normal pressure for 12 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 9 g of asphalt-based carbon fiber was added to 60 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 50 ° C for 10 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C and dried for 12 hours to obtain oxidized carbon fiber for standby use.

[0039] (2) 8 g of the oxidized carbon fiber obtained in step (1) and 60 mg of phytic acid were completely dispersed in 150 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 36 h in a constant temperature water bath at 40 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0040] (3) Weigh 4 g of dried phytic acid modified carbon fiber and completely disperse it in 50 mL of deionized water. Then heat the carbon fiber and water mixture to 60 ° C, add 1.44 g of ferric chloride hexahydrate and 1.12 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 45 minutes, and then quickly add 1.6 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 2 hours and then stop the reaction. After standing for 2 hours, the reaction product is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0041] (4) After 90 g of vinyl silicone oil, 3 g of hydrogenated silicone oil, and 0.5 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 15 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm by a high-speed homogenizer for 4 minutes. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 25 minutes, and then the carbon fiber and silicone mixture was placed in an external magnetic field for 1.5 hours. Finally, it was cured in a vacuum drying oven at 120 ° C for 2 hours to obtain an oriented carbon fiber filled silicone composite material.

[0042] Example 3

[0043] (1) 10 g of asphalt-based carbon fiber was dispersed in 80 mL of acetone. After reflux reaction at 50 ° C and normal pressure for 12 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 9 g of asphalt-based carbon fiber was added to 60 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 50 ° C for 10 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C and dried for 12 hours to obtain oxidized carbon fiber for standby use.

[0044] (2) 8 g of the oxidized carbon fiber obtained in step (1) and 60 mg of phytic acid were completely dispersed in 150 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 36 h in a constant temperature water bath at 40 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0045] (3) Weigh 4 g of dried phytic acid modified carbon fiber and completely disperse it in 50 mL of deionized water. Then heat the carbon fiber and water mixture to 60 ° C, add 1.44 g of ferric chloride hexahydrate and 1.12 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 45 minutes, and then quickly add 1.6 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 2 hours and then stop the reaction. After standing for 2 hours, the reaction product is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0046] (4) After 90 g of vinyl silicone oil, 3 g of hydrogenated silicone oil, and 0.5 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 10 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm by a high-speed homogenizer for 4 minutes. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 25 minutes, and then the carbon fiber and silicone mixture was placed in an external magnetic field for 1.5 hours. Finally, it was cured in a vacuum drying oven at 120 ° C for 2 hours to obtain an oriented carbon fiber filled silicone composite material.

[0047] Example 4

[0048] (1) 10 g of asphalt-based carbon fiber was dispersed in 80 mL of acetone. After reflux reaction at 50 ° C and normal pressure for 12 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 9 g of asphalt-based carbon fiber was added to 60 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 50 ° C for 10 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C and dried for 12 hours to obtain oxidized carbon fiber for standby use.

[0049] (2) 8 g of the oxidized carbon fiber obtained in step (1) and 60 mg of phytic acid were completely dispersed in 150 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 36 h in a constant temperature water bath at 40 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0050] (3) Weigh 4 g of dried phytic acid modified carbon fiber and completely disperse it in 50 mL of deionized water. Then heat the carbon fiber and water mixture to 60 ° C, add 1.44 g of ferric chloride hexahydrate and 1.12 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 45 minutes, and then quickly add 1.6 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 2 hours and then stop the reaction. After standing for 2 hours, the reaction product is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0051] (4) After 90 g of vinyl silicone oil, 3 g of hydrogenated silicone oil, and 0.5 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 20 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm by a high-speed homogenizer for 4 minutes. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 25 minutes, and then the carbon fiber and silicone mixture was placed in an external magnetic field for 1.5 hours. Finally, it was cured in a vacuum drying oven at 120 ° C for 2 hours to obtain an oriented carbon fiber filled silicone composite material.

[0052] Example 5

[0053] (1) 20 g of asphalt-based carbon fiber was dispersed in 100 mL of acetone. After reflux reaction at 60 ° C and normal pressure for 10 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 10 g of asphalt-based carbon fiber was added to 70 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 60 ° C for 12 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C and dried for 12 hours to obtain oxidized carbon fiber for standby use.

[0054] (2) 10 g of the oxidized carbon fiber obtained in step (1) and 80 mg of phytic acid were completely dispersed in 200 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 48 h in a constant temperature water bath at 50 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0055] (3) Weigh 5 g of dried phytic acid modified carbon fiber and completely disperse it in 50 mL of deionized water. Then heat the mixture of phytic acid modified carbon fiber and water to 70 ° C. Then add 2.16 g of ferric chloride hexahydrate and 1.68 g of ferrous sulfate heptahydrate to the mixture. After continuing to heat and stir for 60 minutes, quickly add 2.4 g of sodium hydroxide to the mixed solution to make the iron ions coprecipitate and deposit on the surface of the asphalt-based carbon fiber. After continuing the reaction for 3 hours, stop the reaction. After standing for 3 hours, separate the reaction product, filter it under reduced pressure, and dry it to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0056] (4) After 100 g of vinyl silicone oil, 4 g of hydrogenated silicone oil, and 0.7 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 20 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm with a high-speed homogenizer for 5 minutes. Subsequently, the carbon fiber and silicone mixture were degassed in a vacuum drying oven at 40 ° C for 30 minutes, and then the carbon fiber and silicone mixture were placed in an external magnetic field for 1.5 hours. Finally, they were cured in a vacuum drying oven at 140 ° C for 1 hour to obtain an oriented carbon fiber filled silicone composite material.

[0057] Example 6

[0058] (1) 5 g of asphalt-based carbon fiber was dispersed in 60 mL of acetone. After reflux reaction at 40 ° C and normal pressure for 14 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 8 g of asphalt-based carbon fiber was added to 50 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 60 ° C for 8 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain oxidized carbon fiber for standby use.

[0059] (2) 5 g of the oxidized carbon fiber obtained in step (1) and 35 mg of phytic acid were completely dispersed in 100 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 48 h in a constant temperature water bath at 30 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0060] (3) Weigh 3 g of dried phytic acid modified carbon fiber and completely disperse it in 40 mL of deionized water. Then heat the mixture of phytic acid modified carbon fiber and water to 70 ° C, add 0.9 g of ferric chloride hexahydrate and 0.45 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 30 minutes, and then quickly add 0.8 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 2.5 hours and then stop the reaction. After standing for 1 hour, the reaction product is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0061] (4) After 100 g of vinyl silicone oil, 2.5 g of hydrogenated silicone oil, and 0.3 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 10 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm for 3 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 15 minutes, and then the carbon fiber and silicone mixture was placed in an external magnetic field for 1 hour. Finally, it was cured in a vacuum drying oven at 1000 ° C for 3 hours to obtain an oriented carbon fiber filled silicone composite material.

[0062] Example 7

[0063] (1) 5 g of asphalt-based carbon fiber was dispersed in 60 mL of acetone. After reflux reaction at 40 ° C and normal pressure for 14 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 8 g of asphalt-based carbon fiber was added to 50 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 60 ° C for 8 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain oxidized carbon fiber for standby use.

[0064] (2) 5 g of the oxidized carbon fiber obtained in step (1) and 40 mg of phytic acid were completely dispersed in 100 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 24 h in a constant temperature water bath at 50 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0065] (3) Weigh 3 g of dried phytic acid modified carbon fiber and completely disperse it in 40 mL of deionized water. Then heat the mixture of phytic acid modified carbon fiber and water to 70 ° C, add 1.35 g of ferric chloride hexahydrate and 1.2 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 30 minutes, and then quickly add 1.5 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 1 hour and then stop the reaction. After standing for 1 hour, the reaction product is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0066] (4) After 80 g of vinyl silicone oil, 2 g of hydrogenated silicone oil, and 0.3 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 15 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm for 3 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 15 minutes, and then the carbon fiber and silicone mixture was placed in an external magnetic field for 1 hour. Finally, it was cured in a vacuum drying oven at 1000 ° C for 3 hours to obtain an oriented carbon fiber filled silicone composite material.

[0067] Comparative Example 1

[0068] 100 g of vinyl silicone oil, 4 g of hydrogenated silicone oil, and 0.7 g of Karstedt catalyst were mixed uniformly, and then stirred and homogenized at 12,000 rpm using a high-speed homogenizer for 5 minutes. Subsequently, the mixture was degassed in a vacuum drying oven at 40°C for 30 minutes, and finally cured in a vacuum drying oven at 140°C for 1 hour to obtain a pure silicone material.

[0069] It should be noted that when the carbon fiber filling amount is 0, the unmodified carbon fiber filled silicone composite material, the unoriented carbon fiber filled silicone composite material and the oriented carbon fiber filled silicone composite material are the same material, that is, pure silicone material.

[0070] Comparative Example 2

[0071] (1) 10 g of asphalt-based carbon fiber was dispersed in 80 mL of acetone. After reflux reaction at 50 ° C and normal pressure for 12 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 9 g of asphalt-based carbon fiber was added to 60 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 50 ° C for 10 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C and dried for 12 hours to obtain oxidized carbon fiber for standby use.

[0072] (2) 8 g of the oxidized carbon fiber obtained in step (1) and 60 mg of phytic acid were completely dispersed in 150 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 36 h in a constant temperature water bath at 40 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0073] (3) Weigh 4 g of phytic acid modified carbon fiber and completely disperse it in 50 mL of deionized water. Then heat the mixture of phytic acid modified carbon fiber and water to 60 ° C, add 1.44 g of ferric chloride hexahydrate and 1.12 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 45 minutes, and then quickly add 1.6 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 2 hours and then stop the reaction. After the reaction product is allowed to stand for 2 hours, it is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0074] (4) After 90 g of vinyl silicone oil, 3 g of hydrogenated silicone oil, and 0.5 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 15 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm for 4 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 25 minutes, and then cured in a vacuum drying oven at 120 ° C for 2 hours to obtain an unoriented carbon fiber filled silicone composite material.

[0075] Comparative Example 3

[0076] (1) 10 g of asphalt-based carbon fiber was dispersed in 80 mL of acetone. After reflux reaction at 50 ° C and normal pressure for 12 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 9 g of asphalt-based carbon fiber was added to 60 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 50 ° C for 10 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C and dried for 12 hours to obtain oxidized carbon fiber for standby use.

[0077] (2) 8 g of the oxidized carbon fiber obtained in step (1) and 60 mg of phytic acid were completely dispersed in 150 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 36 h in a constant temperature water bath at 40 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0078] (3) Weigh 4 g of phytic acid modified carbon fiber and completely disperse it in 50 mL of deionized water. Then heat the mixture of phytic acid modified carbon fiber and water to 60 ° C, add 1.44 g of ferric chloride hexahydrate and 1.12 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 45 minutes, and then quickly add 1.6 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 2 hours and then stop the reaction. After the reaction product is allowed to stand for 2 hours, it is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0079] (4) After 90 g of vinyl silicone oil, 3 g of hydrogenated silicone oil, and 0.5 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 10 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm for 4 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 25 minutes, and then cured in a vacuum drying oven at 120 ° C for 2 hours to obtain an unoriented carbon fiber filled silicone composite material.

[0080] Comparative Example 4

[0081] (1) 10 g of asphalt-based carbon fiber was dispersed in 80 mL of acetone. After reflux reaction at 50 ° C and normal pressure for 12 hours, the reaction product was filtered under reduced pressure and rinsed with acetone, and dried in a vacuum drying oven at 50 ° C for 12 hours. After drying, 9 g of asphalt-based carbon fiber was added to 60 mL of a binary mixed acid solution of concentrated sulfuric acid and concentrated nitric acid. After reacting at 50 ° C for 10 hours, the reaction product was diluted with a large amount of deionized water and filtered under reduced pressure. During filtration, the product was washed with a large amount of deionized water until the filtrate was neutral. After filtration, the asphalt-based carbon fiber was placed in a vacuum drying oven at 50 ° C and dried for 12 hours to obtain oxidized carbon fiber for standby use.

[0082] (2) 8 g of the oxidized carbon fiber obtained in step (1) and 60 mg of phytic acid were completely dispersed in 150 mL of deionized water. The phytic acid and the asphalt-based carbon fiber obtained in step (1) were fully reacted for 36 h in a constant temperature water bath at 40 ° C under magnetic stirring. The reaction product was then subjected to vacuum filtration and rinsed with a large amount of deionized water. The reaction product was placed in a vacuum drying oven at 50 ° C for 12 hours to obtain phytic acid-modified carbon fiber.

[0083] (3) Weigh 4 g of phytic acid modified carbon fiber and completely disperse it in 50 mL of deionized water. Then heat the mixture of phytic acid modified carbon fiber and water to 60 ° C, add 1.44 g of ferric chloride hexahydrate and 1.12 g of ferrous sulfate heptahydrate to the mixture, continue heating and stirring for 45 minutes, and then quickly add 1.6 g of sodium hydroxide to the mixed solution to make the iron ions co-precipitate and deposit on the surface of the asphalt-based carbon fiber. Continue the reaction for 2 hours and then stop the reaction. After the reaction product is allowed to stand for 2 hours, it is separated by magnetism, filtered under reduced pressure, and dried to obtain asphalt-based carbon fiber modified with phytic acid and magnetic ferroferric oxide nanoparticles, which is recorded as phytic acid-ferroferric oxide modified carbon fiber and set aside.

[0084] (4) After 90 g of vinyl silicone oil, 3 g of hydrogenated silicone oil, and 0.5 g of Karstedt catalyst were evenly mixed, the phytic acid-ferroferric oxide modified carbon fiber obtained in step (3) was added according to 20 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm for 4 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 25 minutes, and then cured in a vacuum drying oven at 120 ° C for 2 hours to obtain an unoriented carbon fiber filled silicone composite material.

[0085] Comparative Example 5

[0086] After 90g of vinyl silicone oil, 3g of hydrogenated silicone oil and 0.5g of Karstedt catalyst were mixed evenly, the original asphalt-based carbon fiber was added according to 15wt% of the total mass of vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000rpm for 4 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40°C for 25 minutes, and then cured in a vacuum drying oven at 120°C for 2 hours to obtain a carbon fiber filled silicone composite material.

[0087] Comparative Example 6

[0088] After evenly mixing 90 g of vinyl silicone oil, 3 g of hydrogenated silicone oil, and 0.5 g of Karstedt catalyst, the original asphalt-based carbon fiber was added according to 10 wt% of the total mass of the vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000 rpm for 4 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40 ° C for 25 minutes, and then cured in a vacuum drying oven at 120 ° C for 2 hours to obtain an unoriented carbon fiber filled silicone composite material.

[0089] Comparative Example 7

[0090] After 90g of vinyl silicone oil, 3g of hydrogenated silicone oil and 0.5g of Karstedt catalyst were mixed evenly, the original asphalt-based carbon fiber was added according to 20wt% of the total mass of vinyl silicone oil and hydrogenated silicone oil, and stirred and homogenized at 12000rpm for 4 minutes using a high-speed homogenizer. Subsequently, the carbon fiber and silicone mixture was degassed in a vacuum drying oven at 40°C for 25 minutes, and then cured in a vacuum drying oven at 120°C for 2 hours to obtain an unoriented carbon fiber filled silicone composite material.

[0091] Magnetic Properties of Phytic Acid and Magnetic Ferroferric Oxide Nanoparticle Co-Modified Carbon Fibers: The magnetic properties of carbon fibers co-modified with phytic acid and magnetic Ferroferric Oxide Nanoparticles were measured using a LakeShore 8600 magnetic measurement system. The modified carbon fiber samples were thoroughly dried before testing. The test was performed at room temperature over a range of -20,000 Oe to 20,000 Oe. The saturation magnetization of the modified carbon fibers was determined based on the hysteresis loop of the modified pitch-based carbon fibers.

[0092] The magnetic response performance of the phytic acid-ferroferric oxide modified carbon fiber sample prepared in Example 2 was tested using a vibrating sample magnetometer. The hysteresis loop of the phytic acid-ferroferric oxide modified carbon fiber sample is shown in FIG. Figure 2 As shown. Phytic acid-ferroferric oxide modified carbon fibers have significant magnetic responsiveness. As the strength of the external test magnetic field changes, the magnetization intensity of the phytic acid-ferroferric oxide modified carbon fibers also changes. As the strength of the external magnetic field gradually increases, the magnetization intensity of the phytic acid-ferroferric oxide modified carbon fibers also increases. At the same time, the rate of increase of the magnetization intensity of the phytic acid-ferroferric oxide modified carbon fibers gradually slows down. At a higher external magnetic field strength, the magnetization intensity of the phytic acid-ferroferric oxide modified carbon fibers gradually reaches saturation. The saturation magnetization intensity of the phytic acid-ferroferric oxide modified carbon fibers is 5.8 emu·g -1 , with good ferromagnetic properties, which also proves that the magnetic ferroferric oxide nanoparticles have been successfully modified onto the surface of asphalt-based carbon fibers, and there is a strong binding effect between the magnetic ferroferric oxide nanoparticles and the asphalt-based carbon fibers.

[0093] The phytic acid-ferroferric oxide modified carbon fibers prepared in Example 2 were uniformly dispersed in an aqueous solution. Optical photographs of the phytic acid-ferroferric oxide modified carbon fibers dispersed in an aqueous solution without and with an external magnetic field applied are shown below. Figure 3 As shown. Figure 3 As shown in a in FIG, when no external magnetic field is applied, the phytic acid-ferroferric oxide modified carbon fiber can be uniformly dispersed in the aqueous phase to form a uniform black mixture of phytic acid-ferroferric oxide modified carbon fiber and water, as shown in FIG. Figure 3 As shown in Figure b, when an external magnetic field is applied, the phytic acid-ferroferric oxide modified carbon fibers can be attracted to one side of the magnet under the action of the magnetic field, resulting in a very obvious interface between the aggregated phytic acid-ferroferric oxide modified carbon fibers and water. This proves that the phytic acid-ferroferric oxide modified carbon fibers have good magnetic responsiveness and can respond to an external magnetic field and move in a directional manner under the action of the magnetic field. The good magnetic responsiveness of phytic acid-ferroferric oxide modified carbon fibers provides a basis for the preparation of pitch-based carbon fiber / organic silicon composite thermal conductive materials with directional orientation of pitch-based carbon fibers.

[0094] Thermal conductivity testing of oriented carbon fiber-filled silicone composites: The thermal conductivity of different samples was measured using a LongGwin 9389 thermal resistance tester from Shanghai Longwin. First, 30 mm × 30 mm square samples of the oriented carbon fiber-filled silicone composites were prepared with thicknesses of 1 mm, 1.5 mm, and 2 mm. The thermal resistance of samples of varying thicknesses was measured, and the thermal conductivity of each sample was calculated based on its thermal resistance and thickness.

[0095] The thermal conductivity of the unoriented carbon fiber filled silicone composite materials prepared in Comparative Examples 2 to 4, the oriented carbon fiber filled silicone composite materials prepared in Examples 2 to 4, and the unmodified carbon fiber filled silicone composite materials prepared in Comparative Examples 5 to 7 at different carbon fiber filling amounts were tested using a thermal resistance tester. The experimental results are shown in FIG. Figure 4 As shown in the figure. When the carbon fiber filling amount gradually increases from 0 to 20wt%, the thermal conductivity of the unoriented carbon fiber filled silicone composite and the unmodified carbon fiber filled silicone composite shows a gradual increasing trend, while the thermal conductivity of the oriented carbon fiber filled silicone composite shows a trend of first increasing and then decreasing. At the same carbon fiber filling amount, the thermal conductivity of the oriented carbon fiber filled silicone composite is much higher than that of the unoriented carbon fiber filled silicone composite and the unmodified carbon fiber filled silicone composite. This may be mainly due to two reasons. On the one hand, when the phytic acid-ferroferric oxide modified carbon fiber is appropriately filled, it can be better oriented under the action of an external magnetic field, causing the orientation direction of the carbon fiber to be consistent with the phonon transmission direction, thereby effectively improving the thermal conductivity of the silicone composite. On the other hand, when the filling amount of the phytic acid-ferroferric oxide modified carbon fiber is too high, it will not only lead to a large amount of interfacial thermal resistance, but also increase the steric hindrance, inhibiting the orientation of the carbon fiber in the silicone matrix, and to a certain extent reducing the thermal conductivity of the composite. When the filling amount of phytic acid-ferroferric oxide modified carbon fiber is 15wt%, the thermal conductivity of the oriented carbon fiber filled silicone composite is 1.857 Wm -1 K -1 , which is 2.52 times the thermal conductivity of the unoriented carbon fiber filled silicone composite material at the same filling amount, 3.37 times the thermal conductivity of the pure silicone material without carbon fiber filling, and 2.22 times the thermal conductivity of the unmodified carbon fiber filled silicone composite material. This proves that the silicone composite material filled with oriented phytic acid-ferroferric oxide modified carbon fiber has a more complete thermal conduction path and higher thermal conductivity.

[0096] Thermal imaging testing of oriented carbon fiber-filled silicone composites: A FLIR T540 infrared thermal imaging analyzer from the United States was used to analyze the various samples, recording thermal images of the samples during the heating process. Each sample was prepared into a block sample measuring 20 mm in length, 20 mm in width, and 2 mm in height. After maintaining a constant temperature at room temperature, the sample was transferred to a heating table and heated at 60°C. During the heating process, the sample was photographed using an infrared thermal imager, with one image taken every 5 seconds, for a total of 10 images per sample. The time and temperature curves of the different samples, combined with the thermal images, were used to analyze the heat transfer rate of the composite samples at different carbon fiber loadings.

[0097] The heat transfer rate of the oriented carbon fiber filled silicone composite material was analyzed by infrared thermal imaging analysis technology at different filling amounts of 0, 10wt%, 15wt% and 20wt% of the phytic acid-ferroferric oxide modified carbon fibers prepared in Comparative Example 1 and Examples 2 to 3. The thermal imaging pictures of the oriented carbon fiber filled silicone composite material at different time points are as follows: Figure 5 As shown in a in the figure, the corresponding heating curves of each sample are as follows Figure 5As shown in Figure 2b, the infrared thermal images show that the temperature of the oriented carbon fiber-filled silicone composites at different carbon fiber loadings gradually increases with heating time. Under infrared thermal imaging, the color of each oriented carbon fiber-filled silicone composite sample gradually changes from dark blue-purple to light golden yellow. Furthermore, the speed of color change varies across the composite samples at different time points, demonstrating that the organosilicon composites filled with different phytic acid-ferroferric oxide-modified carbon fibers exhibit different heat transfer capabilities. The greater the heat transfer capability of the oriented carbon fiber-filled silicone composite, the faster the color change. Notably, after 50 seconds of heating, the colors of the oriented carbon fiber-filled silicone composite samples, filled with different phytic acid-ferroferric oxide-modified carbon fibers, all ultimately approach golden yellow, with no significant color differences between the samples. This is likely due to the heat absorption and heat dissipation of each oriented carbon fiber-filled silicone composite sample reaching thermal equilibrium, leading to a gradual stabilization of the composite temperature. The heating curves of oriented carbon fiber-filled silicone composites at different carbon fiber loadings also show similar results. Each oriented carbon fiber-filled silicone composite sample exhibited a rapid heating rate during the first 20 seconds of heating. Subsequently, the heating rate gradually plateaued, slowing until the temperature of each composite sample stabilized. At 15wt% and 20wt% phytic acid-ferroferric oxide-modified carbon fiber loadings, the heating rates of the oriented carbon fiber-filled silicone composite samples were significantly higher than those at other loadings. In particular, the 15wt% oriented carbon fiber-filled silicone composite sample entered the temperature plateau the earliest. The significant differences in the heating rates and heat transfer capabilities of the oriented carbon fiber-filled silicone composites at different phytic acid-ferroferric oxide-modified carbon fiber loadings are primarily related to the loading and orientation of the phytic acid-ferroferric oxide-modified carbon fibers in the silicone matrix. In the time interval of 0 to 20 seconds, the heating rate of the oriented carbon fiber filled silicone composite sample with a phytic acid-ferroferric oxide modified carbon fiber filling content of 15wt% was 1.41℃ / s, which was much higher than the heating rate of other composite samples. This is mainly because the phytic acid-ferroferric oxide modified carbon fiber can be fully oriented in the silicone matrix at the appropriate filling amount, thereby forming an efficient heat transfer path, which is conducive to improving the heat transfer capacity of the oriented carbon fiber filled silicone composite. The thermal imaging images and heating curve experimental results show that the silicone composite filled with oriented phytic acid-ferroferric oxide modified carbon fiber has a fast heating rate and high heat transfer efficiency. When used as a thermal conductive interface material, it is beneficial to improve the thermal management level of electronic equipment and electronic components.

[0098] Mechanical Properties of Different Samples: The mechanical properties of the samples were tested using an electronic universal tensile testing machine. First, according to the national standard GB / T1040-2018, the different samples were prepared into dumbbell-shaped specimens with a gauge length of 20 mm, an aspect ratio of 5:1, and a thickness of approximately 2 mm. Before testing, the specimen thickness was accurately measured using a vernier caliper. The specimens were then tested at a tensile rate of 10 mm / min. Each sample was tested five times in parallel, and the average of the test results was used to characterize the sample's tensile strength, elastic modulus, and elongation at break.

[0099] The mechanical properties of the unoriented carbon fiber filled silicone composite materials prepared in Comparative Examples 2 to 4 and the oriented carbon fiber filled silicone composite materials prepared in Examples 2 to 4 at different carbon fiber filling amounts, including tensile strength, elastic modulus and elongation at break, were tested and analyzed using an electronic universal tensile testing machine. The experimental results are shown in Figure 2. Figure 6-Figure 8As shown. From the overall mechanical properties of the composite materials, the tensile strength, elastic modulus and elongation at break of the unoriented carbon fiber filled silicone composite materials and the oriented carbon fiber filled silicone composite materials all show an increasing trend with the increase of the phytic acid-ferroferric oxide modified carbon fiber filling amount. This is mainly because the phytic acid-ferroferric oxide modified carbon fiber can play a mechanical reinforcement role in the silicone composite materials, thereby improving the mechanical properties of the silicone composite materials. At the same carbon fiber filling amount, the tensile strength, elastic modulus and elongation at break of the unoriented carbon fiber filled silicone composite materials are all higher than those of the corresponding oriented carbon fiber filled silicone composite materials. This may be because the tensile test direction of the electronic universal testing machine is perpendicular to the orientation direction of the phytic acid-ferroferric oxide modified carbon fiber in the silicone composite materials, which leads to the deterioration of the ability of the oriented carbon fiber filled silicone composite materials to withstand fracture stress. When the carbon fiber loading was 10wt%, the tensile strengths of the unoriented carbon fiber-filled silicone composite and the oriented carbon fiber-filled silicone composite were 0.145 MPa and 0.130 MPa, respectively, the elastic modulus was 0.168 MPa and 0.133 MPa, and the elongation at break was 119.5% and 109.4%, respectively. With increasing phytic acid-ferroferric oxide modified carbon fiber content, the tensile strength, elastic modulus, and elongation at break of the unoriented carbon fiber-filled silicone composite and the oriented carbon fiber-filled silicone composite increased. When the phytic acid-ferroferric oxide modified carbon fiber loading was 15wt%, the tensile strengths of the unoriented carbon fiber-filled silicone composite and the oriented carbon fiber-filled silicone composite were 0.158 MPa and 0.138 MPa, the elastic modulus was 0.176 MPa and 0.157 MPa, and the elongation at break was 131.2% and 118.6%, respectively. This shows that the directional orientation of phytic acid-ferroferric oxide modified carbon fibers in silicone composites will lead to the loss of some mechanical properties of the composites at the corresponding carbon fiber filling content, but the oriented carbon fiber filled silicone composites still have relatively high tensile strength, elastic modulus and elongation at break, which can meet the mechanical property requirements of thermal conductive composites.

[0100] Shore hardness testing of various samples: The Shore hardness of the various samples was measured using an O-type rubber durometer from Taizhou AiCe Instrument Co., Ltd. The test sample was placed on a firm, horizontal surface. The durometer was held vertically with the indenter at least 12 mm from the edge of the sample. The indenter was pressed vertically into the sample. The hardness reading was taken within one second of the indenter making full contact with the sample. The hardness reading was repeated five times at different locations at least 6 mm apart, and the average value was calculated.

[0101] The Shore hardness of the unoriented carbon fiber filled silicone composite materials prepared in Comparative Examples 2 to 4 and the oriented carbon fiber filled silicone composite materials prepared in Examples 2 to 4 was measured by a Shore hardness tester. The Shore hardness test results of the unoriented carbon fiber filled silicone composite materials and the oriented carbon fiber filled silicone composite materials at different carbon fiber filling amounts are shown in FIG. Figure 9 As shown in Figure 2, the Shore hardness of both unoriented carbon fiber-filled and oriented carbon fiber-filled silicone composites increases with increasing carbon fiber content, exhibiting a similar pattern of change as the tensile strength, elastic modulus, and elongation at break of these two silicone composites. At the same phytic acid-ferroferric oxide-modified carbon fiber loading, the Shore hardness of the oriented carbon fiber-filled silicone composite is much higher than that of the unoriented carbon fiber-filled silicone composite. This is primarily because the phytic acid-ferroferric oxide-modified carbon fibers are vertically oriented within the silicone composite. When the oriented carbon fiber-filled silicone composite is subjected to external forces, the vertically oriented phytic acid-ferroferric oxide-modified carbon fibers provide greater resistance in the direction of the external force. When the carbon fiber loading is 10wt%, the Shore hardness of the unoriented carbon fiber-filled and oriented carbon fiber-filled silicone composites is 41.0 H00 and 50.4 H00, respectively. As the carbon fiber loading increases to 20wt%, the Shore hardnesses of the unoriented carbon fiber-filled silicone composite and the oriented carbon fiber-filled silicone composite reach 48.0 H00 and 58.2 H00, respectively. At this point, the Shore hardness of the oriented carbon fiber-filled silicone composite is 1.21 times that of the unoriented carbon fiber-filled silicone composite. This demonstrates that the silicone composite filled with phytic acid-ferroferric oxide-modified carbon fibers has higher Shore hardness and compressive strength at the same carbon fiber loading.

[0102] Volume Resistivity Testing of Different Samples: The resistance of the samples was measured using an iviumstst.h electrochemical workstation from ivium (Netherlands), and the volume resistivity of each sample was calculated. Each sample was first prepared into a rectangular 10 mm × 10 mm × 2 mm cube. The sample was placed between two sensors on the electrochemical workstation and tested using the transient DC impedance method at 25°C. The volume resistivity of each sample was calculated based on the resistance values ​​obtained.

[0103] The volume resistivity of the unoriented carbon fiber filled organosilicon composites prepared in Examples 2 to 4 and the oriented carbon fiber filled organosilicon composites prepared in Examples 2 to 4 were tested using an electrochemical workstation at different filling amounts of phytic acid-ferroferric oxide modified carbon fiber. The experimental results are shown in Figure 2. Figure 10As shown. The volume resistivity of the unoriented carbon fiber filled silicone composite and the oriented carbon fiber filled silicone composite shows an overall downward trend with the increase of the phytic acid-ferroferric oxide modified carbon fiber filling amount. This is mainly because the carbon fiber itself has good conductivity, and the increase of the carbon fiber filling amount in the silicone matrix is ​​conducive to the transmission of electrons. At the same phytic acid-ferroferric oxide modified carbon fiber filling amount, the volume resistivity of the oriented carbon fiber filled silicone composite is slightly lower than that of the unoriented carbon fiber filled silicone composite. This may be due to the orientation of the phytic acid-ferroferric oxide modified carbon fiber in the silicone matrix. Overall, the volume resistivity of the unoriented carbon fiber filled silicone composite and the oriented carbon fiber filled silicone composite is at a relatively high level. This shows that although the filling of phytic acid-ferroferric oxide modified carbon fiber reduces the volume resistivity of the composite, the unoriented carbon fiber filled silicone composite and the oriented carbon fiber filled silicone composite still have high electrical insulation. When the filling amount of phytic acid-ferroferric oxide modified carbon fiber is 15wt%, the volume resistivity of the oriented carbon fiber filled silicone composite is 3.14 × 10 11 Ω·cm. When the phytic acid-ferroferric oxide modified carbon fiber is filled at a higher loading, the volume resistivity of the oriented carbon fiber filled silicone composite material can still meet the electrical insulation requirements of the thermal conductive interface material.

[0104] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0105] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing an oriented carbon fiber filled organosilicon composite material, characterized in that: The following steps are involved: In an organic solvent, the carbon fiber is surface treated to remove organic impurities, and then oxidized to obtain oxidized carbon fiber; Adding oxidized carbon fibers and phytic acid into water, a complexation reaction occurs at 30°C to 50°C to obtain phytic acid-modified carbon fibers; The phytic acid-modified carbon fibers were added to water, and ferric chloride and ferrous sulfate were added at 50°C to 70°C. The iron ions were fixed on the surface of the phytic acid-modified carbon fibers through the chelation effect of phytic acid and iron ions. Sodium hydroxide was added to cause a coprecipitation reaction to obtain phytic acid-ferrosoferric oxide-modified carbon fibers. After vinyl silicone oil, hydrogenated silicone oil and catalyst are evenly mixed, phytic acid-ferroferric oxide modified carbon fibers are added, homogenized and degassed, and then the phytic acid-ferroferric oxide modified carbon fibers are oriented and arranged along the direction of the magnetic field in an external magnetic field, and then cured to obtain an oriented carbon fiber filled silicone composite material.

2. The method for preparing an oriented carbon fiber filled organosilicon composite material according to claim 1, characterized in that: The ratio of oxidized carbon fiber to phytic acid is 1g:7mg~8mg, and the reaction time of the complexation reaction is 24h~48h.

3. The method for preparing an oriented carbon fiber filled organosilicon composite material according to claim 1, characterized in that: The mass ratio of phytic acid modified carbon fiber and ferric chloride is 10:3~4.5; The mass ratio of phytic acid modified carbon fiber to ferrous sulfate is 10:1.5~4.

4. The method for preparing an oriented carbon fiber filled organosilicon composite material according to claim 1, characterized in that: The mass ratio of phytic acid modified carbon fiber and sodium hydroxide is 1:0.2~0.5; The reaction time of the coprecipitation reaction is 1h~3h.

5. The method for preparing an oriented carbon fiber filled organosilicon composite material according to claim 1, characterized in that: The mass ratio of vinyl silicone oil to hydrogenated silicone oil is 100:2.5~4; the mass ratio of vinyl silicone oil to catalyst is 100:0.3~0.

7.

6. The method for preparing an oriented carbon fiber filled organosilicon composite material according to claim 1, characterized in that: The addition amount of phytic acid-ferroferric oxide modified carbon fiber is 10%~20% of the total mass of vinyl silicone oil and hydrogen silicone oil.

7. The method for preparing an oriented carbon fiber filled organosilicon composite material according to claim 1, characterized in that: The time of applying the external magnetic field is 1h~1.5h.

8. The method for preparing an oriented carbon fiber filled organosilicon composite material according to claim 1, characterized in that: Surface treatment is done at 40℃~60℃ for 10h~14h; The oxidation treatment uses nitric acid and sulfuric acid as a solution and is carried out at 40℃~60℃ for 4-6 hours.

9. An oriented carbon fiber filled organosilicon composite material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the oriented carbon fiber filled organosilicon composite material according to claim 9 in preparing a thermal conductive material.

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