Wave-absorbing epoxy resin composition, structure-function integrated carbon fiber composite material and preparation method of structure-function integrated carbon fiber composite material

Abstract

The invention provides a wave-absorbing epoxy resin composition, a structure-function integrated carbon fiber composite material and a preparation method of the structure-function integrated carbon fiber composite material, and belongs to the technical field of epoxy resin materials. A plurality of wave absorbing agents are added into a modified epoxy resin matrix, and then the modified epoxy resin matrix is compounded with carbon fibers to obtain the structure-function integrated carbon fiber composite material. The obtained composite material has excellent mechanical property and wave-absorbing property, the requirements of wave-absorbing materials of modern structures are met, the wave-absorbing efficiency of the material is remarkably improved due to application of various types of aerogel in the composite material, and particularly, the lowest reflectivity reaches-21.26 dB within the frequency band of 8-18 GHz.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy resin materials, and in particular to a wave-absorbing epoxy resin composition and a structure-function integrated carbon fiber composite material and a preparation method thereof. Background Art

[0002] Although existing carbon fiber composite materials have excellent mechanical properties, their microwave absorption performance is limited. In order to meet the needs of modern electronic devices for lightweight, high-strength, broadband microwave absorbing materials, it is necessary to develop composite materials with both good microwave absorption and mechanical properties. Summary of the invention

[0003] The purpose of the present invention is to provide an absorbing epoxy resin composition and a structure-function integrated carbon fiber composite material and a preparation method thereof, so as to solve the technical problem that the existing composite materials cannot balance the mechanical properties and the absorbing properties.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a microwave-absorbing epoxy resin composition, comprising an epoxy resin composition and a microwave-absorbing agent;

[0006] The epoxy resin composition comprises the following components in parts by weight:

[0007] 20-40 parts of liquid bisphenol A epoxy resin;

[0008] 5-15 parts of medium molecular weight solid bisphenol A epoxy resin;

[0009] 10-30 parts of phenolic epoxy resin;

[0010] 10-30 parts of o-cresol epoxy resin;

[0011] 10-30 parts of dicyclopentadiene epoxy resin;

[0012] 5-10 parts of dicyandiamide curing agent;

[0013] 0.5 to 3 parts of an accelerator made of organic urea and imidazole.

[0014] Furthermore, the mass ratio of the epoxy resin composition to the wave absorbing agent is 70-90:10-30;

[0015] The mass ratio of the organic urea to imidazole is 1-5:1-5.

[0016] Furthermore, the absorber comprises hyperbranched polyester-based ferrocene HBPE-Fc, BaFe 12 O 19One or more of aerogel, Fe3O4 aerogel and graphene / Fe3O4 composite aerogel.

[0017] Furthermore, the epoxy equivalent of the medium molecular weight solid bisphenol A epoxy resin is 400 to 1000, and the medium molecular weight solid bisphenol A epoxy resin includes one or more of Nan Ya NPES-901, NPES-902H, NPES-903, NPES-904, NPES-904H, NPES-905, NPES-905L and NPES-905H.

[0018] The present invention provides a structure-function integrated carbon fiber composite material, which is composited with a microwave-absorbing epoxy resin composition and carbon fiber;

[0019] The mass ratio of the microwave-absorbing epoxy resin composition to the carbon fiber is 30-70:30-70.

[0020] The present invention also provides a method for preparing a structure-function integrated carbon fiber composite material, comprising the following steps:

[0021] 1) mixing the epoxy resin composition and the microwave absorbing agent by a solution blending method to obtain a microwave absorbing epoxy resin composition;

[0022] 2) compounding the microwave-absorbing epoxy resin composition with carbon fiber to obtain a prepreg;

[0023] 3) The prepreg is pressed into shape by a molding process to obtain a structural-functional integrated carbon fiber composite material.

[0024] Furthermore, in the step 3), the pressing pressure is 1-10 MPa, and the pressing temperature is 80-120°C.

[0025] Furthermore, after the compression molding, the material is heated and cured, the curing temperature is 120-150° C., and the curing time is 0.5-2 hours.

[0026] Beneficial effects of the present invention:

[0027] And by introducing HBPE-Fc, BaFe 12 O 19 Aerogel, Fe3O4 aerogel and graphene / Fe3O4 composite aerogel absorbers, etc., are combined with carbon fiber to prepare composite materials with excellent mechanical properties and absorbing properties. This material not only has good absorbing properties in the 8-18 GHz frequency band, but also exhibits high strength and thermal stability. DETAILED DESCRIPTION

[0028] The present invention provides a microwave-absorbing epoxy resin composition, comprising an epoxy resin composition and a microwave-absorbing agent;

[0029] The epoxy resin composition comprises the following components in parts by weight:

[0030] 20-40 parts of liquid bisphenol A epoxy resin;

[0031] 5-15 parts of medium molecular weight solid bisphenol A epoxy resin;

[0032]

[0033] In the present invention, the content of the liquid bisphenol A epoxy resin is preferably 25 to 35 parts by mass, more preferably 28 to 32 parts, and even more preferably 30 parts.

[0034] In the present invention, the content of the medium molecular weight solid bisphenol A epoxy resin is preferably 8 to 12 parts by mass, and more preferably 10 parts.

[0035] In the present invention, the content of the novolac epoxy resin is preferably 15 to 25 parts by mass, more preferably 18 to 22 parts, and even more preferably 20 parts.

[0036] In the present invention, the content of the o-cresol-formaldehyde epoxy resin is preferably 15 to 25 parts by mass, more preferably 18 to 22 parts, and even more preferably 20 parts.

[0037] In the present invention, the content of the dicyclopentadiene epoxy resin is preferably 15 to 25 parts by mass, more preferably 18 to 22 parts, and even more preferably 20 parts.

[0038] In the present invention, the content of the dicyandiamide curing agent is preferably 6 to 9 parts by mass, and more preferably 7 to 8 parts by mass.

[0039] In the present invention, the content of the accelerator compounded of organic urea and imidazole is preferably 1 to 2.5 parts by weight, and more preferably 2 parts by weight.

[0040] In the present invention, the mass ratio of the epoxy resin composition and the absorber is preferably 70-90:10-30; when the mass ratio of the epoxy resin composition and the absorber is 90:10, the low proportion of the absorber mainly maintains the mechanical properties of the epoxy resin. When the absorber content is low, the tensile strength, elongation at break and impact strength of the composite material can still be close to the performance of pure epoxy resin. Due to the low proportion of the absorber, the density of the material is small and can maintain a good lightweight. The addition of a small amount of absorber will not significantly change the overall molecular chain structure and mechanical properties of the epoxy resin matrix. At the same time, the absorbing mechanism (such as dielectric loss and magnetic loss) in the electromagnetic wave absorbing material can still take effect at a lower absorber concentration, but the absorbing performance may be weaker than that of a higher content of absorber. This gradient is suitable for application scenarios with high requirements for mechanical properties and secondary absorbing performance.

[0041] In the present invention, when the mass ratio of the epoxy resin composition and the absorber is 80:20, the medium proportion of the absorber can not only ensure good mechanical properties, but also improve the absorbing ability. Usually at this ratio, the absorbing performance of the composite material can be significantly improved, and the mechanical properties do not change much. Especially in the X-band or Ku-band, the interface between the absorber and the epoxy resin can form more electromagnetic wave scattering points, thereby increasing electromagnetic loss. After adding the absorber, a more uniform dispersion system will be formed inside the material, thereby producing a better electromagnetic matching effect. The absorber particles absorb electromagnetic wave energy through multiple interfaces, reduce the reflection and transmission of electromagnetic waves, and achieve a good absorbing effect. At this time, the mechanical properties are still maintained at a good level, which is suitable for applications that require a more balanced absorption and mechanical properties.

[0042] In the present invention, when the mass ratio of the epoxy resin composition and the absorber is 70:30, the high content of absorber can maximize the absorbing performance, especially the broadband absorbing performance. However, too much absorber will affect the mechanical properties of the composite material, such as reducing the tensile strength and impact strength, and the density is high, and the overall lightweight advantage of the material is weakened. The high content of absorber will form multiple electromagnetic wave reflection and absorption effects in the material, especially when the absorber is a material with magnetic or dielectric loss, it exhibits strong absorbing ability in multiple frequency bands. But at the same time, due to the high filling amount of absorber, the continuous phase structure of epoxy resin is easily destroyed and the mechanical properties are reduced. This gradient is suitable for application scenarios that mainly emphasize absorbing performance, such as high-efficiency absorbing shielding materials.

[0043] In the present invention, the mass ratio of the organic urea to the imidazole is preferably 2-4:2-4, and more preferably 1:1.

[0044] In the present invention, the absorber comprises hyperbranched polyester-based ferrocene HBPE-Fc, BaFe 12 O 19aerogel, Fe3O4 aerogel and graphene / Fe3O4 composite aerogel, preferably BaFe 12 O 19 Aerogel.

[0045] In the present invention, the various properties of the absorber are shown in Table 1 below:

[0046] Table 1 Absorbent

[0047]

[0048]

[0049] In the present invention, the epoxy equivalent of the medium molecular weight solid bisphenol A epoxy resin is 400-1000, preferably 500-900, and more preferably 600-800; the medium molecular weight solid bisphenol A epoxy resin is preferably one or more of Nan Ya NPES-901, NPES-902H, NPES-903, NPES-904, NPES-904H, NPES-905, NPES-905L and NPES-905H.

[0050] The present invention provides a structure-function integrated carbon fiber composite material, which is composited with a microwave-absorbing epoxy resin composition and carbon fiber;

[0051] The mass ratio of the microwave-absorbing epoxy resin composition to the carbon fiber is 30-70:30-70.

[0052] In the present invention, the mass ratio of the microwave absorbing epoxy resin composition to the carbon fiber is preferably 40-60:40-60, more preferably 45-55:45-55, and even more preferably 50:50.

[0053] The present invention also provides a method for preparing a structure-function integrated carbon fiber composite material, comprising the following steps:

[0054] 1) mixing the epoxy resin composition and the microwave absorbing agent by a solution blending method to obtain a microwave absorbing epoxy resin composition;

[0055] 2) compounding the microwave-absorbing epoxy resin composition with carbon fiber to obtain a prepreg;

[0056] 3) The prepreg is pressed into shape by a molding process to obtain a structural-functional integrated carbon fiber composite material.

[0057] In the present invention, the molding process includes a compression molding process or an autoclave molding process, preferably a compression molding process.

[0058] In the present invention, the compounding in step 2) includes a solvent method and a hot melt adhesive method.

[0059] In the present invention, the specific steps of the solvent method are: dissolving the absorbing epoxy resin composition in a solvent to obtain a mixed solution, immersing the carbon fiber in the mixed solution, taking out, heating and drying to remove the solvent, and obtaining a prepreg; the solvent comprises a mixture of one or more of acetone, butanone, xylene, dimethylformamide, and dimethylacetamide, preferably acetone and butanone.

[0060] In the present invention, the hot melt adhesive method is divided into a direct hot melt method and a film adhesive calendering method; the specific steps of the direct hot melt adhesive method are:

[0061] The microwave-absorbing epoxy resin composition is heated to be melted, and the carbon fiber is unwound, impregnated, extruded, dried, and finally rolled up to obtain a prepreg.

[0062] In the present invention, the specific steps of the film adhesive calendering method are: heating the absorbing epoxy resin composition and then conveying it to the dipping roller, by setting the speed and the distance between the dipping rollers, making adhesive films of different thicknesses, then leading the carbon fiber out through the unwinding device, and then sandwiching it with the prepared adhesive film, melting the resin matrix through the heating roller, impregnating it in the fiber, and finally cooling, adding PE film, cutting and winding to obtain prepreg.

[0063] In the present invention, in the step 3), the pressing pressure is 1-10 MPa, preferably 2-9 MPa, more preferably 3-8 MPa, and more preferably 4-6 MPa; the pressing temperature is 80-120°C, preferably 90-110°C, and more preferably 100°C.

[0064] In the present invention, the material is heated and cured after compression molding, the curing temperature is 120-150° C., preferably 130-140° C., and more preferably 135° C.; the curing time is 0.5-2 h, and preferably 1 h.

[0065] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0066] Example 1

[0067] The epoxy resin composition comprises the following components in parts by weight:

[0068]

[0069] The compounding mass ratio of organic urea to imidazole is 2:1.

[0070] Preparation of structural-functional integrated carbon fiber composite materials:

[0071] The epoxy resin composition and the hyperbranched polyester-based ferrocene HBPE-Fc are mixed in a mass ratio of 90:10 to obtain a microwave absorbing epoxy resin composition;

[0072] A method for preparing a structural-functional integrated carbon fiber composite material, wherein the prepreg is prepared by a membrane glue calendering method using a prepreg-specific device and the absorbing epoxy resin composition described in Example 1 and carbon fiber, and then a compression molding process is adopted to lay the prepreg in a mold, press-form the prepreg at 80°C and 5MPa pressure, and then place the prepreg at 120°C for high temperature curing for 2h to obtain a structural-functional integrated carbon fiber composite material HBPE-Fc / EP / CF.

[0073] Example 2

[0074] The epoxy resin composition comprises the following components in parts by weight:

[0075]

[0076] The compounding mass ratio of organic urea to imidazole is 1:2.

[0077] The epoxy resin composition and BaFe 12 O 19 The aerogels are mixed in a mass ratio of 80:20 to obtain a microwave absorbing epoxy resin composition;

[0078] The preparation method of the structure-function integrated carbon fiber composite material is the same as that in Example 1, and BaFe 12 O 19 Aerogel / EP / CF.

[0079] Example 3

[0080] The epoxy resin composition comprises the following components in parts by weight:

[0081]

[0082] The compounding mass ratio of organic urea to imidazole is 1:2.

[0083] The epoxy resin composition and the Fe3O4 aerogel are mixed in a mass ratio of 70:30 to obtain a microwave absorbing epoxy resin composition;

[0084] The preparation method of the structure-function integrated carbon fiber composite material is the same as that in Example 1, and Fe3O4 aerogel / EP / CF is obtained.

[0085] Example 4

[0086] The epoxy resin composition comprises the following components in parts by weight:

[0087]

[0088] The compounding mass ratio of organic urea to imidazole is 2:1.

[0089] The epoxy resin composition and the graphene / Fe3O4 composite aerogel are mixed in a mass ratio of 85:15 to obtain a microwave absorbing epoxy resin composition;

[0090] The preparation method of the structure-function integrated carbon fiber composite material is the same as that in Example 1, and graphene / Fe3O4 composite aerogel / EP / CF is obtained.

[0091] The composite material obtained in the above examples was tested for performance, and the results are shown in Table 2:

[0092] Table 2 Performance test results

[0093]

[0094]

[0095] It can be seen from the above embodiments that the present invention provides an absorbing epoxy resin composition and a structural-functional integrated carbon fiber composite material and a preparation method thereof. The present invention prepares a high-strength absorbing composite material by compounding an EHBP-modified epoxy resin matrix with a variety of absorbers, which has both excellent mechanical properties and absorbing properties and meets the requirements of modern structural absorbing materials. It can be seen from Table 2 that the tensile strength, elongation at break and impact strength of the composite material are significantly improved compared with the pure epoxy resin matrix, indicating its superiority in mechanical properties and absorbing properties. The application of various types of aerogels in composite materials significantly improves the absorbing efficiency of the material, especially in the 8-18 GHz frequency band, with the reflectivity reaching a minimum of -21.26 dB.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A microwave absorbing epoxy resin composition, characterized in that: Comprising an epoxy resin composition and a wave absorbing agent; The epoxy resin composition comprises the following components in parts by weight:

2. The microwave-absorbing epoxy resin composition according to claim 1, characterized in that: The mass ratio of the epoxy resin composition to the wave absorbing agent is 70-90:10-30; The mass ratio of the organic urea to imidazole is 1-5:1-5.

3. The microwave absorbing epoxy resin composition according to claim 1 or 2, characterized in that: The absorber comprises hyperbranched polyester-based ferrocene HBPE-Fc, BaFe 12 O 19 One or more of aerogel, Fe3O4 aerogel and graphene / Fe3O4 composite aerogel.

4. The microwave absorbing epoxy resin composition according to claim 3, characterized in that: The epoxy equivalent of the medium molecular weight solid bisphenol A epoxy resin is 400-1000, and the medium molecular weight solid bisphenol A epoxy resin includes one or more of Nan Ya NPES-901, NPES-902H, NPES-903, NPES-904, NPES-904H, NPES-905, NPES-905L and NPES-905H.

5. A structural-functional integrated carbon fiber composite material, characterized in that: Composed of the microwave-absorbing epoxy resin composition according to any one of claims 1 to 4 and carbon fiber; The mass ratio of the microwave-absorbing epoxy resin composition to the carbon fiber is 30-70:30-70.

6. The method for preparing the structural-functional integrated carbon fiber composite material according to claim 5, characterized in that: The following steps are involved: 1) mixing the epoxy resin composition and the microwave absorbing agent by a solution blending method to obtain a microwave absorbing epoxy resin composition; 2) Compounding the microwave-absorbing epoxy resin composition with carbon fiber to obtain a prepreg; 3) The prepreg is pressed into shape by a molding process to obtain a structural-functional integrated carbon fiber composite material.

7. The preparation method according to claim 6, characterized in that: In the step 3), the pressing pressure is 1-10 MPa, and the pressing temperature is 80-120°C.

8. The preparation method according to claim 6 or 7, characterized in that: After compression molding, the material is heated and cured, the curing temperature is 120-150° C., and the curing time is 0.5-2 hours.

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