CN116554644A - A carbon fiber composite material with thermal conductivity and interlayer toughening and preparation method thereof - Google Patents

Abstract

The invention discloses a carbon fiber composite material with heat conduction and interlayer toughening and a preparation method thereof. The preparation method is as follows: absorbing silver-doped boron nitride nanosheets on carbon fiber felt to obtain functionalized carbon fiber felt, laying up functionalized carbon fiber felt and carbon fiber cloth, pouring epoxy resin under vacuum conditions, and curing Composite materials are prepared. Compared with traditional particles, the functionalized carbon fiber mat prepared by the present invention has good toughness, simple process, and strong operability; and due to the addition of silver-modified boron nitride nanosheets, the carbon fiber The felt has excellent thermal conductivity, and the tensile strength, bending strength and fracture toughness of the prepared composite material are slightly improved, and the thermal conductivity is significantly improved, which has a good application prospect.

Description

A carbon fiber composite material with thermal conductivity and interlayer toughening and preparation method thereof

technical field

The invention relates to a method for preparing a carbon fiber composite material with both heat conduction and interlayer toughening, and belongs to the technical field of carbon fiber composite materials.

Background technique

With the development of electronic devices in the aerospace field towards high frequency, high integration and high power, the problem of thermal energy management of materials has become more and more prominent. In addition, carbon fiber composite structures in the fields of aircraft, space stations and satellites will generate a lot of heat during operation or be affected by the environment and need to be discharged in time to avoid affecting the working accuracy and efficiency of the device. However, traditional carbon fiber composites generally have relatively low thermal conductivity, especially poor thermal conductivity in the thickness direction, and are prone to heat accumulation, resulting in large thermal stress, which affects their service performance and service life. Therefore, traditional carbon fiber composite materials urgently need to improve their thermal conductivity while maintaining the original excellent mechanical properties.

Carbon fiber composite materials mostly appear in the form of plates in the application of structural parts. The carbon fibers in the plates are often arranged along the in-plane direction, so the composite materials have good thermal conductivity in the plane. The carbon fibers are mainly bonded to each other by epoxy resin, so the carbon fiber composite laminate is mainly limited by the thermal conductivity of the interlayer resin, and generally exhibits low thermal conductivity in the thickness direction. Therefore, how to improve the thermal conductivity of carbon fiber composite laminates in the thickness direction has become a key issue that needs to be solved urgently in the development of high thermal conductivity carbon fiber composite materials.

At present, the method of improving the thermal conductivity of carbon fiber composites in the thickness direction is mainly to surface treat carbon fibers. This method often affects the performance of carbon fibers themselves, resulting in poor mechanical properties, especially toughness, of carbon fiber composites, which limits its development.

Chinese patent CN201811494596.X (disclosure date: July 30, 2021) discloses a carbon nanotube toughened high thermal conductivity pitch-based carbon fiber composite material and its preparation method. The method uses a strong acid to modify the surface of the carbon fiber and prepares it using a strong acid system The surface-modified carbon nanotube film is prepared by hot-melting the surface-modified carbon fiber into a prepreg, and finally the prepreg and the carbon nanotube film are laminated to prepare a composite material by autoclave molding. However, since the surface of carbon fiber treated with strong acid is easy to damage the performance of carbon fiber itself, the cost of autoclave molding is relatively high, which is not conducive to actual production.

Chinese patent CN201710110321.0 (disclosure date June 23, 2020) discloses a method for preparing a graphene/carbon nanotube reinforced and toughened carbon fiber composite material. The method uses graphene and modified carbon nanotubes to prepare a sizing agent. And apply it on the surface of carbon fiber to prepare graphene/carbon nanotube reinforced and toughened carbon fiber composite. This method can increase the wettability of the fiber surface and effectively protect the performance of the carbon fiber itself, but it has limitations in improving the interlayer toughness of the composite material and the thermal conductivity in the thickness direction.

In the journal paper Enhanced both in-plane and through-thickness thermalconductivity of carbon fiber/epoxy composites by fabricating high thermalconductive coaxial PAN/PBO carbon fibers (Composites Part B 229(2022) 109468) reported a method using polyparaphenylene benzo Dioxazole (PBO) and graphene are used to treat carbon fibers on the surface to effectively improve the thermal conductivity of carbon fiber composites in the thickness direction. However, this method uses nitric acid to activate carbon fibers and damage the fibers themselves. Therefore, the final Tensile properties of carbon fiber composites decrease.

Contents of the invention

The technical problem to be solved by the present invention is to provide a carbon fiber composite material with both heat conduction and interlayer toughening and its preparation method, which is used to improve the thermal conductivity of the carbon fiber composite material in the thickness direction and overcome the problems caused by the self-modification of carbon fiber. The problem of the decline in mechanical properties of the carbon fiber composite material is simple and pollution-free, which has both thermal conductivity and interlayer toughening.

In order to solve the above technical problems, the present invention provides a method for preparing a carbon fiber composite material with both heat conduction and interlayer toughening: adsorbing silver-doped boron nitride nanosheets on carbon fiber mats to obtain functionalized carbon fiber mats, and combining functional Lay carbon fiber felt and carbon fiber cloth, pour epoxy resin under vacuum conditions, and cure to prepare composite materials.

Preferably, the preparation method of the carbon fiber composite material with thermal conductivity and interlayer toughening includes the following steps:

Step 1): Boron nitride powder is placed in a reducing organic solvent 1, and boron nitride nanosheets are obtained after ultrasonic treatment and centrifugal drying;

Step 2): blending the obtained boron nitride nanosheets with a surface stabilizer and an organic solvent 2, dripping an aqueous solution of a silver salt for reaction, and then vacuum filtering and drying to obtain silver-modified boron nitride nanosheets;

Step 3): Disperse the obtained silver-modified boron nitride nanosheets in deionized water to obtain a uniform and stable silver-modified boron nitride nanosheet dispersion, and impregnate the carbon fiber felt in the silver-modified boron nitride nanosheet dispersion In, after drying, functionalized carbon fiber felt is obtained;

Step 4): Lay functionalized carbon fiber felt and carbon fiber cloth to obtain a preformed body of carbon fiber composite material, pour it into epoxy resin under vacuum conditions, and heat and cure it to obtain both thermal conductivity and interlayer toughening carbon fiber composite materials.

More preferably, in the step 1), the mass concentration of boron nitride in the organic solvent 1 is 5-10%; the organic solvent 1 includes N,N-dimethylformamide, 1,4-butanedi At least one of alcohol, 1,6-hexanediol, and hydrazine hydrate; the power of the ultrasonic treatment is 300-500W, and the time is 30-60min.

More preferably, in the step 1), the boron nitride powder has an aspect ratio of 10-20; the obtained boron nitride nanosheets have an aspect ratio of 20-50.

More preferably, in the step 2), the surface stabilizer is at least one of polyvinylpyrrolidone, polyethylene glycol, and cetyltrimethylammonium bromide; The mass ratio of the solvent is 100:(3～10); the organic solvent 2 includes N,N-dimethylformamide, N,N-dimethylacetamide, isopropanol, dimethyl sulfoxide At least one; the mass concentration of the boron nitride nanosheets in the organic solution 2 is 2-5%.

More preferably, in the step 2), the silver salt includes at least one of silver chloride, silver fluoride, and silver nitrate; the mass concentration of the aqueous solution of the silver salt is 0.01 to 0.05%; the temperature of the reaction The temperature is 40-80 DEG C; the particle size of the silver particles in the obtained silver-modified boron nitride nano-sheets is 10-50 nm; the aspect ratio of the obtained silver-modified boron nitride nano-sheets is 20-50.

More preferably, in the step 3), the mass concentration of the silver-modified boron nitride nanosheet dispersion is 0.01-0.1%; and the impregnation time is 30-60 minutes.

More preferably, in the step 4), the thickness of the carbon fiber felt is 2-4 mm; the thickness of the carbon fiber cloth is 0.1-0.5 mm; the epoxy resin is E-51, E-54, E-42 At least one of epoxy resins; the pouring temperature of the epoxy resin is 50-80° C., the curing temperature is 100-180° C., and the curing time is 2-4 hours. According to the test standard of ASTM D5528 interlayer I fracture toughness and ASTM D7905 interlayer II fracture toughness, a layer of carbon fiber felt is laid on the middle layer of multilayer carbon fiber cloth (according to the test standard, the total thickness of the carbon fiber composite material is 4mm).

The present invention also provides a carbon fiber composite material with heat conduction and interlayer toughening prepared by the above preparation method.

On the basis of using carbon felt to toughen the interlayer of carbon fiber composite materials, the present invention builds a three-dimensional heat conduction filler passage by means of a carbon felt skeleton, thereby improving the heat conduction performance in the thickness direction of carbon fiber composite materials, and has the advantages of convenient operation, controllable reaction and excellent performance The advantages.

Compared with prior art, the beneficial effect of the present invention is:

(1) The functional nano-filler used in the present invention utilizes the size-shape effect formed by nano-silver particles and micron boron nitride to produce a synergistic heat conduction effect with the short carbon fibers inside the carbon fiber felt.

(2) The present invention controls the content of the silver-modified boron nitride nanosheets attached to the carbon fiber felt by adjusting the concentration of the silver-modified boron nitride nanosheet dispersion, effectively avoiding the problem that the nanofillers are easy to agglomerate in the epoxy resin.

(3) The present invention utilizes carbon fiber felt as an intercalated toughened carbon fiber composite material, while helping silver-modified boron nitride nanosheets to form a thermal conduction path along the internal structure of the carbon fiber felt, effectively improving the thickness direction thermal conductivity of the carbon fiber composite material.

(4) The preparation method of the carbon fiber composite material with high thermal conductivity and high toughness described in the present invention has a simple process and strong operability, and at the same time realizes interlayer heat conduction and toughening of the carbon fiber composite material, and has a good application prospect.

Description of drawings

Fig. 1 is the microscopic morphology of the silver boron nitride nanosheet prepared in embodiment 1;

Fig. 2 is the microscopic appearance of the carbon fiber felt of the adsorption silver boron nitride nanoplate that embodiment 1 prepares;

Fig. 3 is the surface optical photograph of the carbon fiber composite material prepared by embodiment 1;

4 is a side optical photo of the carbon fiber composite material prepared in Example 1.

Detailed ways

In order to make the present invention more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

Example 1

A method for preparing a carbon fiber composite material with thermal conductivity and interlayer toughening:

(1) Disperse the boron nitride powder in N,N-dimethylformamide solvent to prepare a dispersion with a concentration of 5wt%, the ultrasonic treatment power is 300W, and the boron nitride with an aspect ratio of 20 is obtained after centrifugal drying Nanosheets;

(2) Blend the boron nitride nanosheets obtained in step (1) with polyethylene glycol and N,N-dimethylacetamide to prepare a boron nitride nanosheet dispersion with a concentration of 2wt%, and drop in a concentration of 0.01 A wt% silver nitrate aqueous solution was reacted at 40°C, vacuum filtered and dried to obtain silver-modified boron nitride nanosheets with an aspect ratio of 20;

(3) Place the silver-modified boron nitride nanosheets obtained in step (2) into deionized water to prepare a dispersion with a concentration of 0.01wt%, immerse the carbon fiber felt in the silver-modified boron nitride nanosheet dispersion for 30min, and then dry to obtain Functionalized carbon fiber felt;

(4) Lay the 2mm functionalized carbon fiber felt obtained in step (3) and 0.1mm carbon fiber cloth, the layer ratio is 5:6, and pour E-51 epoxy resin under vacuum conditions, and the pouring temperature is 50°C. The curing temperature is 100°C, and the curing time is 2 hours to obtain the carbon fiber resin matrix composite material.

After testing, compared with carbon fiber felt, the hydrophilicity of functionalized carbon fiber felt is significantly improved, and the contact angle is reduced from 105° to 82°. The thermal conductivity of the carbon fiber resin matrix composite is 2.3W/m·K, and the interlaminar mode I and mode II fracture toughness are increased by 54.2% and 46.5%, respectively.

Example 2

A method for preparing a carbon fiber composite material with thermal conductivity and interlayer toughening:

(1) Disperse the boron nitride powder in 1,4-butanediol solvent to prepare a dispersion with a concentration of 5wt%, the ultrasonic treatment power is 300W, and the boron nitride nanosheets with an aspect ratio of 20 are obtained after centrifugal drying ;

(2) The boron nitride nanosheets obtained in step (1) are blended with cetyltrimethylammonium bromide and isopropanol to prepare a boron nitride nanosheet dispersion with a concentration of 2wt%. 0.01wt% silver chloride aqueous solution, reacted at 40°C, vacuum filtered and dried to obtain silver-modified boron nitride nanosheets with an aspect ratio of 30;

(3) Place the silver-modified boron nitride nanosheets obtained in step (2) into deionized water to prepare a dispersion with a concentration of 0.01wt%, immerse the carbon fiber felt in the silver-modified boron nitride nanosheet dispersion for 30min, and then dry to obtain Functionalized carbon fiber felt;

(4) Lay the 2mm functionalized carbon fiber felt obtained in step (3) and the 0.1mm carbon fiber cloth, pour E-51 epoxy resin under vacuum conditions, the pouring temperature is 50°C, the curing temperature is 100°C, and the curing time 2h, the carbon fiber resin matrix composite material is obtained.

After testing, compared with carbon fiber felt, the hydrophilicity of functionalized carbon fiber felt is significantly improved, and the contact angle is reduced from 105° to 80°. The thermal conductivity of the carbon fiber resin matrix composite is 2.6W/m·K, and the interlaminar mode I and mode II fracture toughness are increased by 55.3% and 47.1%, respectively.

Example 3

A method for preparing a carbon fiber composite material with thermal conductivity and interlayer toughening:

(1) Disperse the boron nitride powder in 1,6-hexanediol solvent to prepare a dispersion with a concentration of 5 wt%. The ultrasonic treatment power is 300W, and after centrifugal drying, boron nitride nanosheets with an aspect ratio of 20 are obtained. ;

(2) Blend the boron nitride nanosheets obtained in step (1) with polyvinylpyrrolidone and dimethyl sulfoxide to prepare a dispersion of boron nitride nanosheets with a concentration of 2wt%, and drop them into a concentration of 0.01wt% chloride Silver aqueous solution was reacted at 40°C, vacuum filtered and dried to obtain silver-modified boron nitride nanosheets with an aspect ratio of 30;

(3) Place the silver-modified boron nitride nanosheets obtained in step (2) into deionized water to prepare a dispersion with a concentration of 0.01wt%, immerse the carbon fiber felt in the silver-modified boron nitride nanosheet dispersion for 30min, and then dry to obtain Functionalized carbon fiber felt;

(4) Lay the 2mm functionalized carbon fiber mat obtained in step (3) and the 0.1mm carbon fiber cloth, pour E-54 epoxy resin under vacuum conditions, the pouring temperature is 50°C, the curing temperature is 100°C, and the curing time 2h, the carbon fiber resin matrix composite material is obtained.

After testing, compared with carbon fiber felt, the hydrophilicity of functionalized carbon fiber felt is significantly improved, and the contact angle is reduced from 105° to 84°. The thermal conductivity of the carbon fiber resin matrix composite is 1.8W/m·K, and the interlaminar mode I and mode II fracture toughness are increased by 52.5% and 46.7%, respectively.

Example 4

A method for preparing a carbon fiber composite material with thermal conductivity and interlayer toughening:

(1) Disperse the boron nitride powder in a hydrazine hydrate solvent to prepare a dispersion with a concentration of 5wt%, the ultrasonic treatment power is 300W, and after centrifugal drying, boron nitride nanosheets with an aspect ratio of 20 are obtained;

(2) Blending the boron nitride nanosheets obtained in step (1) with polyvinylpyrrolidone and N,N-dimethylformamide to prepare a boron nitride nanosheet dispersion with a concentration of 2wt%, and drop in a concentration of 0.01 A wt% silver fluoride aqueous solution was reacted at 40°C, vacuum filtered and dried to obtain silver-modified boron nitride nanosheets with an aspect ratio of 20;

(3) Place the silver-modified boron nitride nanosheets obtained in step (2) into deionized water to prepare a dispersion with a concentration of 0.01wt%, immerse the carbon fiber felt in the silver-modified boron nitride nanosheet dispersion for 30min, and then dry to obtain Functionalized carbon fiber felt;

(4) Lay the 2mm functionalized carbon fiber mat obtained in step (3) and the 0.1mm carbon fiber cloth, pour E-54 epoxy resin under vacuum conditions, the pouring temperature is 50°C, the curing temperature is 100°C, and the curing time 2h, the carbon fiber resin matrix composite material is obtained.

After testing, compared with carbon fiber felt, the hydrophilicity of functionalized carbon fiber felt is significantly improved, and the contact angle is reduced from 105° to 75°. The thermal conductivity of the carbon fiber resin matrix composite is 2.6W/m·K, and the interlaminar mode I and mode II fracture toughness are increased by 58.7% and 45.3%, respectively.

Comparative example 1

A preparation method of carbon fiber composite material:

(1) Disperse the boron nitride powder in 1,6-hexanediol solvent to prepare a dispersion with a concentration of 5 wt%. The ultrasonic treatment power is 300W, and after centrifugal drying, boron nitride nanosheets with an aspect ratio of 20 are obtained. ;

(2) Place the boron nitride nanosheets obtained in step (1) into deionized water to prepare a dispersion with a concentration of 0.01 wt%, immerse the carbon fiber felt in the boron nitride nanosheet dispersion for 30min, and then dry to obtain functionalized carbon fibers felt2;

(4) Lay the 2mm functionalized carbon fiber felt obtained in step (3) and the 0.1mm carbon fiber cloth, pour E-51 epoxy resin under vacuum conditions, the pouring temperature is 50°C, the curing temperature is 100°C, and the curing time 2h, the carbon fiber resin matrix composite material is obtained.

After testing, compared with carbon fiber felt, functionalized carbon fiber felt 2 has no obvious improvement effect on hydrophilicity, and the contact angle decreases from 105° to 98°. The thermal conductivity of the carbon fiber resin matrix composite is 1.4W/m·K, and the interlaminar mode I and mode II fracture toughness are increased by 41.6% and 35.5%, respectively.

Claims (9)

1. A method for preparing a carbon fiber composite with heat conduction and interlayer toughening, characterized in that, the silver-doped boron nitride nanosheet is adsorbed on a carbon fiber felt to obtain a functionalized carbon fiber felt, and the functionalized carbon fiber felt and The carbon fiber cloth is laid up, and epoxy resin is poured under vacuum conditions, and the composite material is prepared by curing. 2. The preparation method of heat conduction and interlayer toughened carbon fiber composite material as claimed in claim 1, characterized in that, comprising the following steps: Step 1): Boron nitride powder is placed in a reducing organic solvent 1, and boron nitride nanosheets are obtained after ultrasonic treatment and centrifugal drying; Step 2): blending the obtained boron nitride nanosheets with a surface stabilizer and an organic solvent 2, dripping an aqueous solution of a silver salt for reaction, and then vacuum filtering and drying to obtain silver-modified boron nitride nanosheets; Step 3): Disperse the obtained silver-modified boron nitride nanosheets in deionized water to obtain a uniform and stable silver-modified boron nitride nanosheet dispersion, and impregnate the carbon fiber felt in the silver-modified boron nitride nanosheet dispersion In, after drying, functionalized carbon fiber felt is obtained; Step 4): Lay functionalized carbon fiber felt and carbon fiber cloth to obtain a preformed body of carbon fiber composite material, pour it into epoxy resin under vacuum conditions, and heat and cure it to obtain both thermal conductivity and interlayer toughening carbon fiber composite materials. 3. the preparation method as claimed in claim 2 is characterized in that, in described step 1), the mass concentration of boron nitride in organic solvent 1 is 5～10%; Described organic solvent 1 comprises N, N- At least one of dimethylformamide, 1,4-butanediol, 1,6-hexanediol, and hydrazine hydrate; the power of the ultrasonic treatment is 300-500W, and the time is 30-60min. 4. The preparation method according to claim 2, characterized in that, in said step 1), the aspect ratio of the boron nitride powder is 10 to 20; the aspect ratio of the obtained boron nitride nanosheets is 20 to 50 . 5. preparation method as claimed in claim 2 is characterized in that, described step 2) in, surface stabilizer is at least one in polyvinylpyrrolidone, polyethylene glycol, cetyltrimethylammonium bromide species; the mass ratio of the boron nitride nanosheets to the surface stabilizer is 100:3-10; the organic solvent 2 includes N,N-dimethylformamide, N,N-dimethylacetamide, iso At least one of propanol and dimethyl sulfoxide; the mass concentration of the boron nitride nanosheets in the organic solution 2 is 2-5%. 6. preparation method as claimed in claim 2 is characterized in that, described step 2) in, silver salt comprises at least one in silver chloride, silver fluoride, silver nitrate; The quality of the aqueous solution of described silver salt The concentration is 0.01-0.05%; the temperature of the reaction is 40-80°C; the particle size of the silver particles in the obtained silver-modified boron nitride nanosheets is 10-50nm; the aspect ratio of the obtained silver-modified boron nitride nanosheets is 20 ~50. 7. The preparation method according to claim 2, characterized in that, in the step 3), the mass concentration of the silver-modified boron nitride nanosheet dispersion is 0.01-0.1%; the time of the immersion is 30-60min . 8. the preparation method as claimed in claim 2 is characterized in that, in described step 4), the thickness of carbon fiber felt is 2～4mm; The thickness of described carbon fiber cloth is 0.1～0.5mm; Described epoxy resin is At least one of E-51, E-54, and E-42 epoxy resins; the pouring temperature of the epoxy resin is 50-80°C, the curing temperature is 100-180°C, and the curing time is 2-4 hours. 9. A carbon fiber composite material with thermal conductivity and interlayer toughening prepared by the preparation method according to any one of claims 1-8.