A method for preparing dielectric regulated fiber-reinforced resin-based composite material

Abstract

The present invention discloses a method for preparing a dielectric control fiber reinforced resin-based composite material, which relates to the technical field of dielectric composite materials. A resin matrix and a solvent are mixed to prepare a resin solution, and then dielectric control filler particles are added to the resin solution to prepare a resin / filler mixed dispersion; the resin / filler mixed dispersion is evenly coated on a fiber fabric to prepare a dielectric control fiber fabric prepreg; the dielectric control fiber fabric prepreg is cut and laid, and vacuum heated and cured to prepare a dielectric control fiber reinforced resin-based composite material. This method is suitable for the dielectric performance regulation of various fiber reinforced resin-based composite materials, while the composite materials maintain relatively excellent mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of dielectric composite materials, and in particular to a method for preparing a dielectric regulated fiber-reinforced resin-based composite material. Background Art

[0002] Fiber-reinforced resin-based composite materials are one of the important categories in the field of wave-transmitting functional materials. They are usually composed of reinforced fibers and a resin matrix. They have excellent wave-transmitting properties while meeting certain mechanical requirements. They are widely used in military and civilian fields such as radar antenna covers, antenna windows, and communication base station antenna covers.

[0003] The dielectric properties of wave-transmitting composite materials, namely the dielectric constant and dielectric loss, are important factors affecting their wave-transmitting performance. Commonly used resin matrices include epoxy resins, cyanate esters, phenolic resins, polyaryl acetylene, etc., while commonly used fibers include quartz fibers, glass fibers, and organic fibers such as polyimide. Usually, the dielectric properties of the resin matrix and reinforcing fibers are fixed, so when the resin matrix, the fibers, and the ratio of the two are determined, the dielectric properties of the composite materials prepared therefrom are also fixed. On the other hand, even different types of resin matrices and different fibers usually have similar dielectric properties, so the controllability of the dielectric properties of the composite materials is poor. In this case, the design of the electrical properties of the radome can only be carried out under the constraints of the inherent dielectric properties of the material, which to a certain extent constrains the multifunctional integration and development of the radome, limits the improvement of electrical performance, and does not meet the needs of broadband high wave transmission.

[0004] Filling the resin matrix with particles with different dielectric properties can usually adjust the dielectric properties of the composite material, but it will lead to a decrease in processing performance and mechanical properties to a certain extent. Fiber fabrics can effectively improve the mechanical properties of resin materials, but the degree of regulation of dielectric properties is small. Moreover, most of the current methods for regulating the dielectric properties of composite materials are passive, that is, first determine the filling content and then determine the dielectric properties, and then further design and prepare the antenna cover based on the dielectric properties; it is impossible to control the composite material according to the dielectric performance requirements. Based on the above background, in order to meet the requirements of the development of antenna covers for their own electrical properties, it is urgent to provide a method to actively and controllably construct fiber-reinforced resin-based composite materials with different dielectric properties, and to achieve precise regulation and preparation according to the dielectric performance requirements, while also maintaining the mechanical properties of the composite material. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a method for preparing a dielectrically regulated fiber-reinforced resin-based composite material, which is suitable for regulating the dielectric properties of various fiber-reinforced resin-based composite materials, while the composite material maintains relatively excellent mechanical properties.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a dielectric regulated fiber-reinforced resin-based composite material comprises the following steps:

[0008] (1) Preparation of resin glue and blending with filler particles: a resin matrix is ​​mixed with a solvent and dissolved by stirring to prepare a resin solution, and then dielectric control filler particles are added to the resin solution, and a resin / filler mixed dispersion is prepared by stirring and ultrasonic dispersion steps;

[0009] (2) Preparation of fiber fabric prepreg: The above-mentioned resin / filler mixed dispersion is evenly coated on the fiber fabric, and a dielectrically controlled fiber fabric prepreg is prepared by solvent volatilization and vacuum solvent removal steps;

[0010] (3) Preparation of dielectric regulated fiber reinforced resin-based composite materials: The dielectric regulated fiber fabric prepreg is cut and laid according to a preset method, and vacuum heated and cured to obtain a dielectric regulated fiber reinforced resin-based composite material.

[0011] Preferably, the resin matrix is ​​at least one of cyanate ester, epoxy resin, bismaleimide resin and phenolic resin.

[0012] Preferably, the solvent is at least one of acetone, NN dimethylformamide, NN dimethylacetamide and tetrahydrofuran.

[0013] Preferably, the dielectric control filler particles are at least one of titanium dioxide, barium titanate, aluminum oxide, silicon dioxide, and hollow glass microspheres.

[0014] Preferably, the mass ratio of the resin matrix to the solvent is 1:(0.5-3), preferably 1:(1-2), and the mass ratio of the dielectric regulating filler to the resin matrix is ​​(0.1-1):1.

[0015] Preferably, the stirring treatment time is 1-2 hours, and the ultrasonic dispersion treatment time is 30-60 minutes.

[0016] Preferably, the fiber fabric is one of quartz fiber, glass fiber, polyimide fiber, aramid fiber and PBO fiber.

[0017] Preferably, the mass ratio of the resin matrix to the fiber fabric is (0.3-0.6):1, and the number of coatings is 1-3 times.

[0018] Preferably, the vacuum solvent removal method is: after the solvent evaporates for 24-48 hours in a natural environment, drying in a vacuum oven with a vacuum degree of less than -0.1 MPa for 1-24 hours at an oven temperature of 60-100°C.

[0019] Preferably, the cutting, laying and vacuum heating and curing in a preset manner refers to laying the dielectric regulating fiber fabric prepreg on the mold by manual laying, and laying a porous isolation membrane, breathable cotton felt and vacuum bag on the upper surface of the fiber fabric after laying, vacuuming with vacuum-assisted equipment, and heating and curing.

[0020] Preferably, the vacuum degree of the vacuum extraction is -0.09 to -0.1 MPa.

[0021] Preferably, the temperature rise curing adopts step-by-step temperature rise curing, the curing temperature is 80-240° C., and the total curing time is 4-10 hours.

[0022] Compared with the prior art, the method of the present invention has the following advantages:

[0023] (1) The present invention utilizes resin / fiber fabric prepreg preparation technology and prepares a dielectrically regulated fiber-reinforced resin-based composite material by regulating the content of dielectrically regulated particles in the resin matrix and related process parameters.

[0024] (2) The present invention realizes the combination of filler particles with resin matrix and fiber fabric, and the dispersion of filler particles in composite materials, so as to realize the controllable increase or decrease of the dielectric properties of the composite materials within the range of dielectric constant 2.0-6.0 and dielectric loss less than 0.01, and establishes the corresponding relationship between filler content and dielectric properties through fitting, so as to further realize the goal of accurately regulating and preparing composite materials according to dielectric performance requirements; in addition, the prepared dielectric regulated composite materials also have good mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described below in conjunction with the accompanying drawings:

[0026] Figure 1 The present invention is a flow chart of a method for preparing a dielectrically regulated fiber-reinforced resin-based composite material.

[0027] Figure 2 This is a SEM image of the titanium dioxide filled dielectric regulated fiber reinforced resin matrix composite material of Example 1;

[0028] Figure 3 This is a SEM image of the dielectric-regulated fiber-reinforced resin-based composite material filled with hollow glass microspheres of Example 5;

[0029] Figure 4A This is a graph showing the change in dielectric properties and fitting results of the titanium dioxide filled dielectric regulated fiber reinforced resin matrix composite material of Example 1.

[0030] Figure 4BThis is a graph showing the change in dielectric properties and fitting results of the titanium dioxide filled dielectric regulated fiber reinforced resin matrix composite material of Example 5. DETAILED DESCRIPTION

[0031] The method of the present invention is described in detail below through specific examples. The methods described in the following examples are conventional methods unless otherwise specified; the materials and reagents can be obtained from commercial channels unless otherwise specified.

[0032] It should be noted that, in order to describe the method of the present invention more accurately and specifically, the following examples only select cyanate ester / quartz fiber fabric as a representative to prepare composite materials, but the method of the present invention is not limited thereto, and composite materials of other resins and fiber fabrics can also be prepared by this method.

[0033] Example 1: Add 200g of cyanate prepolymer to 200g of acetone and stir thoroughly until the resin is dissolved, then add 80g of titanium dioxide particles to the solution, stir mechanically for 1h, and then ultrasonically treat for 30min to obtain a mixed suspension. The mixed suspension is evenly coated once on 670g of quartz fiber cloth, then dried at room temperature for 48h and then treated in a 60℃ vacuum oven (hollowness less than -0.1MPa) for 1h to obtain a titanium dioxide / cyanate / quartz fiber prepreg. After the prepreg is cut into a certain size, 12 layers are laid on the mold, followed by a porous isolation membrane, a breathable cotton felt and a vacuum bag. Subsequently, it is cured at 80℃ for 1h, 180℃ for 2h, 200℃ for 2h, and 220℃ for 2h under vacuum conditions of -0.09MPa to prepare a dielectric-regulated fiber-reinforced resin-based composite material.

[0034] Example 2: The difference between this example and Example 1 is that acetone is replaced with NN dimethylformamide, the added amount is 100 g, the mass of titanium dioxide added to the cyanate ester / NN dimethylformamide solution is 100 g, mechanical stirring is 1.5 hours, ultrasonic treatment is performed for 50 minutes, and the remaining steps and conditions are the same as in Example 1.

[0035] Example 3: The difference between this example and Example 1 is that the mass of titanium dioxide added to the cyanate / acetone solution is 140 g, the mixed suspension is evenly coated twice on 400 g of glass fiber, dried at room temperature for 24 hours and then treated in a vacuum at 80°C for 24 hours, and the remaining steps and conditions are the same as in Example 1.

[0036] Example 4: The difference between this example and Example 1 is that epoxy resin is selected as the resin matrix, the mass of titanium dioxide added to the epoxy resin / acetone solution is 200g, and the remaining steps and conditions are the same as those in Example 1.

[0037] Example 5: Add 200g of cyanate prepolymer to 600g of acetone and stir thoroughly until the resin is dissolved, then add 20g of hollow glass microsphere particles to the solution, stir mechanically for 2h, and then ultrasonically treat for 60min to obtain a mixed suspension. The mixed suspension is evenly coated on 330g of quartz fiber cloth three times, then dried at room temperature for 36h and then treated in a 100℃ vacuum oven (hollowness less than -0.1MPa) for 5h to obtain a hollow glass microsphere titanium / cyanate / quartz fiber prepreg. After cutting the prepreg into a certain size, 12 layers are laid on the mold, followed by a porous isolation membrane, a breathable cotton felt and a vacuum bag. Subsequently, the dielectric-regulated fiber-reinforced resin-based composite material is prepared by curing at 80℃ for 2h, 180℃ for 3h, 200℃ for 3h, and 240℃ for 2h under vacuum conditions of -0.1MPa.

[0038] Example 6: The difference between this example and Example 5 is that the mass of the hollow glass microsphere particles added to the cyanate / acetone solution is 60 g, and the step curing conditions are 80°C for 1 h, 180°C for 1 h, 200°C for 1 h, and 220°C for 1 h. The remaining steps and conditions are the same as those in Example 5.

[0039] Example 7: The difference between this example and Example 5 is that the mass of the hollow glass microsphere particles added to the cyanate ester / acetone solution is 100 g, and the remaining steps and conditions are the same as those in Example 5.

[0040] Comparative Example 1: Add 200g of cyanate prepolymer to 200g of acetone and stir thoroughly until the resin is dissolved, then mechanically stir for 1h and then ultrasonically treat for 30min to obtain a mixed solution. The above solution is evenly coated on a quartz fiber cloth, then dried at room temperature for 48h and then treated in a 60℃ vacuum oven for 1h to obtain a cyanate / quartz fiber prepreg. The prepreg is cut into a certain size and 12 layers are laid on the mold, followed by a porous isolation membrane, a breathable cotton felt and a vacuum bag. Subsequently, it is cured at 80℃ for 1h, 180℃ for 2h, 200℃ for 2h, and 220℃ for 2h under vacuum conditions to prepare a fiber-reinforced resin-based composite material.

[0041] Figure 2 The 4 figures are SEM images of the titanium dioxide filled dielectric regulated fiber reinforced resin matrix composite material of Example 1 at different magnifications. It can be seen that the resin matrix can well infiltrate the fibers and fill between the fiber bundles, and the titanium dioxide particles are well dispersed in the resin matrix between the fiber bundles.

[0042] Figure 3The left and right figures are SEM images of the hollow glass microsphere-filled dielectric-regulated fiber-reinforced resin-based composite material of Example 5 at different magnifications. It can be seen that the hollow glass microspheres are dispersed and attached to the surface of the fiber bundle or between the fiber bundles.

[0043] Figure 4A The figure shows the change and fitting results of dielectric properties of fiber-reinforced resin-based composites filled with titanium dioxide and dielectric regulation. Figure 4B The dielectric properties of the titanium dioxide-filled dielectric-regulated fiber-reinforced resin-based composite material in Example 5 are changed and the fitting results are shown. According to the fitting curves of these two figures, it can be seen that the desired dielectric properties can be accurately regulated and selected within the range of dielectric properties to prepare the composite material.

[0044] Table 1: Dielectric controlled fiber reinforced resin matrix composite material performance test data

[0045]

[0046] It can be seen that the fiber-reinforced composite material prepared by the method of the present invention has good dielectric control performance, and can realize controllable adjustment of the dielectric constant of the composite material in the range of 2.0-6.0, and the dielectric loss is less than 0.01, so as to meet the electrical performance requirements of different antenna covers, and solve the problem of poor controllability of dielectric properties of common fiber-reinforced resin-based composite materials. At the same time, due to the reinforcing effect of the fiber fabric in the system, when a higher content of filler is filled, the tensile strength of the composite material is slightly reduced, but still at a high level.

[0047] The method of the present invention has been described in detail above by using specific embodiments and experiments, but it is obvious to those skilled in the art that some modifications or improvements can be made to the method of the present invention on the basis of the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for preparing a dielectrically regulated fiber-reinforced resin-based composite material, characterized in that: The steps include: A resin matrix and a solvent are mixed, wherein the mass ratio of the resin matrix to the solvent is 1:(0.5-3), the resin matrix is ​​at least one of cyanate ester, epoxy resin, bismaleimide resin, and phenolic resin, and a resin solution is prepared by stirring and dissolving, and then dielectric control filler particles are added to the resin solution, wherein the mass ratio of the dielectric control filler to the resin matrix is ​​(0.1-1):1, and the dielectric control filler particles are at least one of titanium dioxide, barium titanate, aluminum oxide, silicon dioxide, and hollow glass microspheres, and a resin / filler mixed dispersion is prepared by stirring and ultrasonic dispersion steps; The resin / filler mixed dispersion is uniformly coated on the fiber fabric, and a dielectric control fiber fabric prepreg is prepared through solvent volatilization and vacuum solvent removal steps; The dielectric regulated fiber fabric prepreg is cut and laid in a preset manner, and vacuum heated and cured to prepare a dielectric regulated fiber reinforced resin-based composite material.

2. The method according to claim 1, characterized in that The solvent is at least one of acetone, NN dimethylformamide, NN dimethylacetamide and tetrahydrofuran.

3. The method according to claim 1, characterized in that The stirring treatment time is 1-2 hours, and the ultrasonic dispersion treatment time is 30-60 minutes.

4. The method according to claim 1, characterized in that The fiber fabric is one of quartz fiber, glass fiber, polyimide fiber, aramid fiber and PBO fiber.

5. The method according to claim 1 or 4, characterized in that The mass ratio of the resin matrix to the fiber fabric is (0.3-0.6):1, and the coating is performed 1-3 times.

6. The method according to claim 1, characterized in that The vacuum desolventizing method is: after the solvent evaporates for 24-48 hours in a natural environment, it is dried in a vacuum oven with a vacuum degree of less than -0.1MPa for 1-24 hours at a temperature of 60-100 o C.

7. The method according to claim 1, characterized in that The cutting, laying and vacuum heating and curing according to a preset method refers to laying the dielectric regulated fiber fabric prepreg on the mold by manual laying, and laying a porous isolation film, breathable cotton felt and vacuum bag on the upper surface of the fiber fabric after laying, and using vacuum auxiliary equipment to draw a vacuum with a vacuum degree of -0.09~-0.1MPa, and then heating and curing.

8. The method according to claim 1, characterized in that The curing temperature is 80-240℃. o C, the total curing time is 4-10h.

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