Multifunctional integrated polyimide composite material and preparation method thereof

Abstract

The invention belongs to the technical field of preparation of resin-based composite materials, and particularly discloses a multifunctional integrated polyimide composite material and a preparation method thereof. According to the preparation method, the polyimide film with the metal layer and the thermosetting polyimide prepreg blank are adopted as raw materials, rapid preparation of the multifunctional integrated polyimide composite material is achieved through a high-temperature and high-pressure co-curing method, and the problems that according to a traditional coating method, adhesive force is insufficient, and effective protection and efficient functionalization cannot be provided are solved. According to the obtained composite material, the oxygen permeability is effectively reduced through tight arrangement of metal atoms in the metal layer, and oxidation erosion of oxygen to the composite material is weakened. Meanwhile, the composite material is endowed with electromagnetic shielding and lightning protection functions due to the conductivity of the surface metal layer, the preparation method is simple, the raw materials are cheap and easy to obtain, the integration of multiple functions of oxidation resistance, electromagnetic shielding and lightning protection is quickly and efficiently realized, and the composite material has a wide application prospect in the field of aerospace.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing resin-based composite materials, and specifically relates to a multifunctional integrated polyimide composite material, and a method for preparing the polyimide composite material based on high temperature and high pressure co-curing. Background Art

[0002] Polyimide resin and its composite materials have excellent comprehensive properties at high temperatures, can be used for a long time at high temperatures (280℃~400℃), and can be used as load-bearing components in high temperature environments. They are widely used in the fields of aviation, aerospace and space technology, especially in aero engines and aerospace planes.

[0003] Polyimide materials are subject to the combined effects of multiple factors such as mechanical, thermal, and oxygen in high-temperature environments, causing them to gradually age and fail. Among them, the effects of heat and oxygen will cause the polyimide molecular chain to break, causing the resin to degrade, causing the resin matrix performance to decay, and ultimately damaging the performance of the composite material. With the continuous improvement of equipment performance, the high performance of aviation equipment also requires polyimide composite materials to have electromagnetic shielding, lightning resistance and other properties, but traditional polyimide composite materials are difficult to integrate multiple functions into one, which requires the surface of the composite material to be modified to meet the current performance requirements.

[0004] At present, in terms of improving the thermal oxidation aging resistance of polyimide composite materials, the traditional protection method is mainly to prepare a layer of ceramic coating on the surface of the composite material in the form of a coating. The protection mechanism of the ceramic coating is to use the low thermal conductivity of the ceramic material to play a heat protection and heat insulation role under short-term high temperature. However, the thickness of the ceramic coating is generally large, and it does not match the thermal expansion coefficient of the base material. After a long time or multiple temperature cycles, it is easy to cause fatigue cracking, thereby generating oxygen pathways, affecting the protection effect, and it is difficult to meet the long-life use requirements. In addition, the ceramic coating is not conductive and cannot take into account the conductivity requirements.

[0005] In terms of improving the electromagnetic shielding, lightning resistance, infrared stealth performance of polyimide composite materials, it is mainly achieved by improving the surface conductivity of the composite material. At present, the traditional method of improving the surface conductivity of the composite material is mainly to form a metal coating on the surface of the composite material by spraying. However, the metal layer produced by spraying is generally thicker and less dense. Although it can be conductive, its thermal oxidation resistance is insufficient, and there is no matching high-temperature putty at this stage, resulting in a weak interface bonding force between it and the composite material. In addition, a surface self-metallization method can also be used to form a metal layer on the surface of the polyimide composite material. Although this method can form a thinner metal layer, it needs to be etched with a strong alkaline solution, which will have an adverse effect on the self-performance of the composite material. More importantly, the coating formation cycle is long, which is not suitable for manufacturing larger parts.

[0006] To solve the above problems, Chinese patent CN112659664B (National University of Defense Technology) discloses an ultra-wideband thermal insulation / stealth / load-bearing / electromagnetic shielding integrated composite material, which includes, from the inside to the outside, a load-bearing / electromagnetic shielding layer, an adhesive layer, a first aerogel composite insulation layer, a first lossy electromagnetic periodic structure layer support layer, a first lossy electromagnetic periodic structure layer, a second aerogel composite insulation layer, a second lossy electromagnetic periodic structure layer support layer, a second lossy electromagnetic periodic structure layer, a third aerogel composite insulation layer, a third lossy electromagnetic periodic structure layer support layer, a third lossy electromagnetic periodic structure layer, a fourth aerogel composite insulation layer and a heat protection layer. The composite material achieves ultra-wideband stealth performance by regulating the electrical properties of the lossy electromagnetic periodic structure layer and the dielectric properties of other layers. The multi-layer heat insulation layer and heat protection layer give it a good heat insulation effect. The use of carbon fiber reinforced resin matrix, on the one hand, gives the composite material a strong load-bearing capacity, on the other hand, the conductivity of carbon fiber can provide a strong electromagnetic shielding function, ensuring that the electronic system of the equipment is not disturbed by the complex external electromagnetic environment. At the same time, it can also serve as an electromagnetic wave reflection backing for the composite material to improve the wave absorption performance of the composite material. However, the preparation process of this multifunctional integrated composite material is complex, the raw materials are diverse, and the production cost is high.

[0007] Therefore, how to realize the multifunctional integration of anti-oxidation, electromagnetic shielding and lightning protection of polyimide composite materials at low cost and in a simpler way is a technical problem that needs to be solved urgently at this stage. Summary of the invention

[0008] The main technical problem solved by the present invention is to provide a method for preparing a multifunctional integrated polyimide composite material based on co-curing. The method comprises bonding a polyimide film having a metal layer to a thermosetting polyimide prepreg blank and then co-curing the resulting materials under high temperature and high pressure. The close arrangement of metal atoms in the metal layer is utilized to effectively reduce the oxygen permeability and weaken the oxidative corrosion of the composite material by oxygen. At the same time, the conductive effect of the metal layer can also give the composite material electromagnetic shielding and lightning protection functions, thereby realizing the multifunctional integration of anti-oxidation, electromagnetic shielding and lightning protection of the polyimide composite material.

[0009] Secondly, the present invention also provides a multifunctional integrated polyimide composite material.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0011] A method for preparing a multifunctional integrated polyimide composite material comprises the following steps:

[0012] The polyimide film with a metal layer is bonded to a thermosetting polyimide prepreg blank, and then co-cured to obtain a multifunctional integrated polyimide composite material.

[0013] As a preferred embodiment of the present invention, one side of the polyimide film has a metal layer. During bonding, the side without the metal layer faces the thermosetting polyimide prepreg blank, and the side with the metal layer faces outward to bond with the prepreg blank.

[0014] Specifically, the polyimide film with a metal layer is a commercially available product.

[0015] As a preferred embodiment of the present invention, the polyimide film is prepared using linear polyimide or thermoplastic polyimide. Among them, thermoplastic polyimide, as a high temperature resistant resin, has higher thermal stability and high creep resistance than traditional thermosetting polyimide. The film material prepared with it as a carrier can not only ensure functional requirements, but also improve the barrier effect on oxygen by utilizing the density of metal.

[0016] As a preferred embodiment of the present invention, the metal in the metal layer is selected from one or more of gold, silver, copper, aluminum and the like.

[0017] As a preferred embodiment of the present invention, the thickness of the metal layer is 0.1-50 μm.

[0018] As a preferred embodiment of the present invention, the method for preparing the thermosetting polyimide prepreg blank comprises:

[0019] Thermosetting polyimide prepreg is layered and then pretreated at 60-210° C. and vacuum degree ≥0.09 MPa to obtain a thermosetting polyimide prepreg blank.

[0020] Specifically, the thermosetting polyimide prepreg includes but is not limited to one or more of unidirectional prepreg, fabric prepreg, and the like.

[0021] Specifically, the pretreatment time is 30 to 90 minutes.

[0022] As a preferred embodiment of the present invention, the bonding uses a polyimide adhesive. The polyimide adhesive is a commercially available product. When in use, the polyimide adhesive is applied to the side of the polyimide film that does not have a metal layer, ensuring that the side with the metal layer faces outward during bonding, so that the metal layer remains on the outer surface of the composite material.

[0023] As a preferred embodiment of the present invention, the polyimide film may be subjected to surface treatment on the side without the metal layer before bonding, including but not limited to one or more of electrochemical treatment, plasma treatment, etc. After the surface treatment, a clean surface can be obtained, which is convenient for bonding and integration with the prepreg blank.

[0024] As a preferred embodiment of the present invention, the bonding is to bond a polyimide film having a metal layer on one side or both sides of the thermosetting polyimide prepreg blank to form a surface functional layer (metal layer) on one side or both sides of the composite material.

[0025] As a preferred embodiment of the present invention, high temperature auxiliary materials are used for packaging after bonding to ensure smooth high temperature and high pressure curing.

[0026] As a preferred embodiment of the present invention, the co-curing is: keeping warm for 100 to 300 minutes at 260 to 400° C. and 0.3 to 2.5 MPa.

[0027] As a preferred embodiment of the present invention, the co-curing is carried out in stages, first keeping warm at 260-350°C for 10-60 minutes, pressurizing to 0.3-2.5MPa, and then heating to 370-400°C and keeping warm and pressurizing for 100-200 minutes to ensure that the prepreg blank and the film are fully cured and bonded.

[0028] A multifunctional integrated polyimide composite material prepared by the method.

[0029] Specifically, the multifunctional integrated polyimide composite material can be applied to scenarios with functional requirements such as anti-oxidation, electromagnetic shielding, and lightning protection.

[0030] Beneficial effects of the present invention:

[0031] The present invention adopts a polyimide film with a metal layer and a thermosetting polyimide prepreg blank as raw materials, and utilizes a high-temperature and high-pressure co-curing method to realize the preparation of a multifunctional integrated polyimide composite material, thereby solving the problems of insufficient adhesion of traditional coating methods, inability to provide effective protection and efficient functionalization, etc. The method is simple and efficient, suitable for batch and industrial production, and has good application prospects and high economic value.

[0032] The present invention bonds the polyimide film with the metal layer on one side facing outward to a thermosetting polyimide prepreg blank. After co-curing, the close arrangement of metal atoms in the metal layer can be used to effectively reduce the oxygen permeability, reduce the oxidative corrosion of oxygen on the composite material, and achieve effective protection of the composite material. At the same time, the conductive effect of the surface metal layer can also give the composite material electromagnetic shielding and lightning protection functions, thereby efficiently realizing the multifunctional integration of anti-oxidation, electromagnetic shielding, and lightning protection, and has broad application prospects in the aerospace field. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the expanded diagram of the multifunctional integrated polyimide composite material.

[0034] Figure 2 Schematic diagram of the structure of a multifunctional integrated polyimide composite material.

[0035] Figure 3 This is a cross-sectional view of the multifunctional integrated polyimide composite material.

[0036] Figures 1 to 3 In the figure, 1 is a metal layer, 2 is a thermoplastic or linear polyimide transition layer, and 3 is a thermosetting polyimide composite material.

[0037] In order to more clearly illustrate the technical solution to be protected by the present invention, the drawings in the embodiments and / or experimental examples are briefly introduced above. It should be understood that the above drawings should not be regarded as any limitation on the protection scope of the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is described in detail below through specific embodiments. The following embodiments are intended to further illustrate the content of the present invention in detail, but are not intended to limit the scope of protection of the claims of the present invention.

[0039] In the following examples and comparative examples, unless otherwise specified, the raw materials, reagents, equipment, etc. used are all commercially available products. Among them, the polyimide film with a metal layer was purchased from Forsman (Beijing) Technology Co., Ltd.; the polyimide adhesive was purchased from the Composites Center of China Aviation Manufacturing Technology Research Institute, product model AC723; the thermosetting polyimide prepreg was purchased from the Composites Center of China Aviation Manufacturing Technology Research Institute, product model CCF800H / AC721.

[0040] Example 1

[0041] This embodiment provides a method for preparing a multifunctional integrated polyimide composite material, comprising the following steps:

[0042] (1) Using CCF800H / AC721 thermosetting polyimide prepreg, according to [0] 16 The designed layers are laid, and the prepreg after laying is pretreated at 150° C. and vacuum degree ≥ 0.09 MPa for 60 minutes to obtain a polyimide prepreg blank.

[0043] (2) A single-sided copper-plated (linear) polyimide film with a thickness of 30 μm is selected, the thickness of the polyimide film is 25 μm, and the thickness of the copper plating layer is 5 μm. Only one side of the polyimide film without a copper plating layer is cleaned with acetone (specifically: wiping with acetone twice and leaving it in the air for 10 minutes before use), and then a layer of polyimide adhesive is applied on the treated surface, which is then laid and bonded to both sides of the prepreg blank obtained in step (1) to obtain a blank containing a functional layer.

[0044] (3) The blank containing the functional layer obtained in step (2) is encapsulated with a high-temperature auxiliary material, and co-cured after encapsulation, firstly kept at 330° C. for 30 minutes, pressurized to 1.5 MPa, and then heated to 385° C. and kept at this temperature and pressure for 120 minutes to obtain a multifunctional integrated polyimide composite material (such as Figures 1 to 3 shown).

[0045] Example 2

[0046] This embodiment provides a method for preparing a multifunctional integrated polyimide composite material, comprising the following steps:

[0047] (1) Using CCF800H / AC721 thermosetting polyimide prepreg, according to [0] 16 The designed layers are laid, and the prepreg after laying is pretreated at 150° C. and vacuum degree ≥ 0.09 MPa for 60 minutes to obtain a polyimide prepreg blank.

[0048] (2) A single-sided copper-plated (thermoplastic) polyimide film with a thickness of 35 μm is selected, the thickness of the polyimide film is 25 μm, and the thickness of the copper plating layer is 10 μm. The non-copper-plated side of the polyimide film is subjected to plasma treatment (technical parameters are: oxygen atmosphere, power of 150 W, and treatment time of 5 min), and then cleaned with acetone (specifically: wiped with acetone twice, and left to air for 10 min before use), and then a layer of polyimide adhesive is applied on the treated surface, which is then laid and bonded to both sides of the prepreg blank obtained in step (1) to obtain a blank containing a functional layer.

[0049] (3) The blank containing the functional layer obtained in step (2) is encapsulated with a high-temperature auxiliary material, and co-cured after encapsulation. It is first kept at 330° C. for 30 minutes, pressurized to 1.5 MPa, and then heated to 385° C. and kept at this temperature and pressure for 120 minutes to obtain a multifunctional integrated polyimide composite material.

[0050] Example 3

[0051] This embodiment provides a method for preparing a multifunctional integrated polyimide composite material, comprising the following steps:

[0052] (1) Using CCF800H / AC721 thermosetting polyimide prepreg, according to [0] 16 The designed layers are laid, and the prepreg after laying is pretreated at 150° C. and vacuum degree ≥ 0.09 MPa for 60 minutes to obtain a polyimide prepreg blank.

[0053] (2) A single-sided copper-plated (thermoplastic) polyimide film with a thickness of 55 μm is selected, the thickness of the polyimide film is 50 μm, and the thickness of the copper plating layer is 5 μm. The non-copper-plated side of the polyimide film is subjected to plasma treatment (technical parameters are: oxygen atmosphere, power of 150 W, and treatment time of 5 min), and then cleaned with acetone (specifically: wiped with acetone twice, and left to air for 10 min before use), and then a layer of polyimide adhesive is applied on the treated surface, which is then laid and bonded to both sides of the prepreg blank obtained in step (1) to obtain a blank containing a functional layer.

[0054] (3) The blank containing the functional layer obtained in step (2) is encapsulated with a high-temperature auxiliary material, and co-cured after encapsulation. It is first kept at 330° C. for 30 minutes, pressurized to 1.5 MPa, and then heated to 385° C. and kept at this temperature and pressure for 120 minutes to obtain a multifunctional integrated polyimide composite material.

[0055] Example 4

[0056] This embodiment provides a method for preparing a multifunctional integrated polyimide composite material, comprising the following steps:

[0057] (1) Using CCF800H / AC721 thermosetting polyimide prepreg, according to [0] 16 The designed layers are laid, and the prepreg after laying is pretreated at 150° C. and vacuum degree ≥ 0.09 MPa for 60 minutes to obtain a polyimide prepreg blank.

[0058] (2) A single-sided aluminum-plated (linear) polyimide film with a thickness of 30 μm is selected, the thickness of the polyimide film is 25 μm, and the thickness of the aluminum coating is 5 μm. The non-aluminum-plated side of the polyimide film is subjected to plasma treatment (technical parameters are: oxygen atmosphere, power of 150 W, and treatment time of 5 min), and then cleaned with acetone (specifically: wiped with acetone twice, and left to air for 10 min before use), and then a layer of polyimide adhesive is applied on the treated surface, which is then laid and bonded to both sides of the prepreg blank obtained in step (1) to obtain a blank containing a functional layer.

[0059] (3) The blank containing the functional layer obtained in step (2) is encapsulated with a high-temperature auxiliary material, and co-cured after encapsulation. It is first kept at 330° C. for 30 minutes, pressurized to 1.5 MPa, and then heated to 385° C. and kept at this temperature and pressure for 120 minutes to obtain a multifunctional integrated polyimide composite material.

[0060] Example 5

[0061] This embodiment provides a method for preparing a multifunctional integrated polyimide composite material, comprising the following steps:

[0062] (1) Using CCF800H / AC721 thermosetting polyimide prepreg, according to [0] 16 The designed layers are laid, and the prepreg after laying is pretreated at 150° C. and vacuum degree ≥ 0.09 MPa for 60 minutes to obtain a polyimide prepreg blank.

[0063] (2) A single-sided silver-plated (linear) polyimide film with a thickness of 30 μm is selected, the thickness of the polyimide film is 25 μm, and the thickness of the silver-plated layer is 5 μm. The non-silver-plated side of the polyimide film is subjected to plasma treatment (technical parameters are: oxygen atmosphere, power of 150 W, and treatment time of 5 min), and then cleaned with acetone (specifically: wiped with acetone twice, and left to air for 10 min before use). Then, a layer of polyimide adhesive is applied on the treated surface, which is then laid and bonded to both sides of the prepreg blank obtained in step (1) to obtain a blank containing a functional layer.

[0064] (3) The blank containing the functional layer obtained in step (2) is encapsulated with a high-temperature auxiliary material, and co-cured after encapsulation. It is first kept at 330° C. for 30 minutes, pressurized to 1.5 MPa, and then heated to 385° C. and kept at this temperature and pressure for 120 minutes to obtain a multifunctional integrated polyimide composite material.

[0065] In other embodiments of the present invention, the raw materials and process parameters in the preparation method can be arbitrarily used or taken within a given range, which will not substantially affect the final performance of the multifunctional integrated polyimide composite material.

[0066] Comparative Example

[0067] This comparative example provides a method for preparing a polyimide composite material, comprising the following steps:

[0068] (1) Using CCF800H / AC721 thermosetting polyimide prepreg, according to [0] 16 The designed layers are laid, and the prepreg after laying is pretreated at 150° C. and vacuum degree ≥ 0.09 MPa for 60 minutes to obtain a polyimide prepreg blank.

[0069] (2) The prepreg blank obtained in step (1) is encapsulated with a high-temperature auxiliary material, and then cured after encapsulation. The prepreg blank is first kept at 330° C. for 30 minutes, pressurized to 1.5 MPa, and then heated to 385° C. and kept at this temperature and pressure for 120 minutes to obtain a polyimide composite material.

[0070] Experimental example

[0071] The multifunctional integrated polyimide composite materials prepared in Examples 1 to 5 were tested for performance. The surface resistivity was tested using a four-probe method, the flexural strength was tested with reference to ASTM D790, the interlaminar shear strength was tested with reference to ASTM D2344, the weight loss rate was aged at 350° C. in a high-temperature oven, and the weight of the sample was tested using a balance before and after aging. The weight loss rate was calculated based on the weight difference before and after aging. The test results are shown in Table 1.

[0072] Table 1 Performance test results of multifunctional integrated polyimide composite materials

[0073]

[0074] It can be seen from Table 1 that the polyimide composite material prepared in the embodiment of the present invention integrates the functions of anti-oxidation, electromagnetic shielding and lightning protection, and has broad application prospects in the field of aerospace.

[0075] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a multifunctional integrated polyimide composite material, characterized in that: The following steps are involved: The polyimide film with a metal layer is bonded to a thermosetting polyimide prepreg blank, and then co-cured to obtain a multifunctional integrated polyimide composite material.

2. The preparation method according to claim 1, characterized in that: One side of the polyimide film has a metal layer, and during bonding, the side without the metal layer is facing the thermosetting polyimide prepreg blank, and the side with the metal layer is facing outward to bond with the prepreg blank; And / or, the polyimide film is prepared using linear polyimide or thermoplastic polyimide.

3. The preparation method according to claim 1, characterized in that: The metal in the metal layer is selected from one or more of gold, silver, copper and aluminum; And / or, the thickness of the metal layer is 0.1-50 μm.

4. The preparation method according to claim 1, characterized in that: The preparation method of the thermosetting polyimide prepreg blank comprises: Thermosetting polyimide prepreg is layered and then pretreated at 60-210° C. and vacuum degree ≥0.09 MPa to obtain a thermosetting polyimide prepreg blank.

5. The preparation method according to claim 4, characterized in that: The thermosetting polyimide prepreg includes but is not limited to one or both of unidirectional prepreg and fabric prepreg; And / or, the pretreatment time is 30 to 90 minutes.

6. The preparation method according to claim 1, characterized in that: The bonding uses a polyimide adhesive, and when in use, the polyimide adhesive is applied to the side of the polyimide film that does not have a metal layer.

7. The preparation method according to claim 1, characterized in that: Before bonding, the polyimide film may be subjected to surface treatment on a side without the metal layer, including but not limited to one or both of electrochemical treatment and plasma treatment.

8. The preparation method according to claim 1, characterized in that: The bonding is to bond a polyimide film having a metal layer to one side or both sides of the thermosetting polyimide prepreg blank; And / or, after the bonding, a high temperature auxiliary material is used for packaging.

9. The preparation method according to claim 1, characterized in that: The co-curing is: keeping the temperature at 260-400°C and 0.3-2.5MPa for 100-300min; And / or, the co-curing is carried out in stages, firstly keeping the temperature at 260-350° C. for 10-60 min, pressurizing to 0.3-2.5 MPa, and then heating to 370-400° C. and keeping the temperature and pressure for 100-200 min.

10. A multifunctional integrated polyimide composite material prepared by the preparation method according to any one of claims 1 to 9.

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