Prepreg for high-temperature-resistant high-toughness bismaleimide resin composite material, composite material and preparation method

Abstract

The invention discloses a prepreg for a high-temperature-resistant and high-toughness bismaleimide resin composite material, the composite material and a preparation method, and belongs to the technical field of hot-melt prepreg and polymer composite materials. The problem that the bismaleimide resin composite material cannot have heat resistance and toughness at the same time is solved. Two toughening modifiers of a diallyl compound and polyimide are adopted to modify bismaleimide resin, and the method comprises the following steps: mixing and grinding the modifiers, adding the bismaleimide resin for polymerization to obtain a bismaleimide resin adhesive, preparing a prepreg from the bismaleimide resin adhesive and fibers by using a hot melting method, and curing to obtain the bismaleimide resin composite material. The bismaleimide resin prepreg and the composite material provided by the invention are simple in preparation method, the prepreg is good in manufacturability at normal temperature and long in storage period, the glass-transition temperature of the composite material is greater than 300 DEG C, the normal-temperature and high-temperature mechanical properties are excellent, and the bismaleimide resin prepreg and the composite material have wide application prospects in the field of aerospace composite materials.

Description

Technical Field

[0001] The invention belongs to the technical field of hot-melt prepregs and polymer composite materials, and relates to a prepreg and a composite material for high-temperature-resistant and high-toughness bismaleimide resin composite materials and a preparation method. Background Art

[0002] With the rapid development of the aerospace field, advanced aircraft have higher and higher performance requirements for composite products. It is difficult for engineered epoxy resins to meet the temperature resistance requirements. Although polyimide resins have excellent heat resistance, the harsh process conditions limit their promotion and application. Bismaleimide resin (BMI) is between epoxy resin and polyimide resin. It has heat resistance close to that of polyimide and basically retains the molding processability of epoxy resin. Therefore, it has been widely favored.

[0003] Although bismaleimide resin has good mechanical properties and heat resistance, the operating temperature is generally between 177 and 230°C, and the glass transition temperature (Tg) is generally greater than 250°C, but the unmodified bismaleimide resin has disadvantages such as poor solubility and high brittleness of the cured product. Among them, poor toughness is the bottleneck of the application and development of bismaleimide resin, which makes it impossible for the composite materials prepared using bismaleimide resin to have both heat resistance and toughness. Summary of the invention

[0004] In order to solve the problem that the composite material prepared by the existing hot-melt bismaleimide resin prepreg cannot meet the requirements of heat resistance and toughness at the same time, the present invention provides a prepreg for high-temperature resistant and high-toughness bismaleimide resin composite material, a composite material and a preparation method.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] One of the purposes of the present invention is to provide a method for preparing a prepreg for a high temperature resistant and high toughness bismaleimide resin composite material, comprising:

[0007] Step 1: Preparation of bismaleimide resin glue:

[0008] The diallyl compound and the polyimide resin are weighed, stirred, and ground, and added into a reactor, and the temperature, heating rate, stirring speed, and dispersion speed of the reactor are set. When the reactor reaches the set temperature, the bismaleimide resin is added, and the stirring speed, dispersion speed, and temperature of the reactor are adjusted again. After reacting for a period of time, the reaction is cooled to obtain a bismaleimide resin glue;

[0009] Step 2: Preparation of bismaleimide resin prepreg:

[0010] The bismaleimide resin adhesive obtained in step one is processed into a resin adhesive film, and then the fiber is impregnated into the resin adhesive film by a hot melt method to obtain a bismaleimide resin prepreg.

[0011] It is further defined that the stirring temperature of the stirring process after weighing in step 1 is 50-80°C.

[0012] It is further defined that the grinding process in step 1 is to fully grind and mix by a three-roll grinder.

[0013] It is further defined that in step 1, when initially set, the reactor temperature is 80-100°C, the heating rate is 1-3°C / min, the stirring speed is 30-50r / min, and the dispersion speed is 600-700r / min.

[0014] It is further defined that during the readjustment in step 1, the stirring speed of the reactor is 50-70 r / min, the dispersion speed is 800-1000 r / min, and the temperature is 120-140°C.

[0015] It is further defined that the reaction time in step 1 is 30 to 60 minutes.

[0016] It is further defined that the cooling temperature in step 1 is to be lowered to 80-100°C.

[0017] It is further defined that the diallyl compound in step 1 is one or more of diallyl bisphenol A, diallyl bisphenol S, and bisphenol A diallyl ether.

[0018] It is further defined that the bismaleimide resin in step 1 is one or more of 4,4-bismaleimidodiphenylmethane, 4,4-bismaleimidodiphenyl sulfone, 4,4-bismaleimidodiphenyl ether, and N,N'-m-phenylene bismaleimide.

[0019] It is further defined that the polyimide resin in step 1 is thermoplastic polyimide powder.

[0020] Further defined, the thermoplastic polyimide powder includes at least one of the following characteristic structures:

[0021]

[0022] It is further defined that in step 1, the mass ratio of the diallyl compound to the polyimide resin is (1-5):1.

[0023] It is further defined that in step 1, the mass ratio of the sum of the mass of the diallyl compound and the polyimide resin to the mass ratio of the bismaleimide resin is (1-2):1.

[0024] It is further defined that the fiber in step 2 is T300 carbon fiber, T700 carbon fiber, T800 carbon fiber, T1000 carbon fiber, M40 carbon fiber, M55 carbon fiber, glass fiber or aramid fiber.

[0025] Further defined, the method for processing the bismaleimide resin glue into a resin glue film in step 2 is: placing the bismaleimide resin glue on a melt frame at 70-80°C to heat and melt it, setting the coating machine hot roller temperature to 80-90°C, the cooling plate temperature to 5-15°C, the coating speed to 10-15 m / min, and adjusting the gap between the hot rollers to make the resin glue film surface density 25-50 g / m 2 .

[0026] Further, in step 2, the parameters of the process of hot-melt impregnation of the fiber into the resin film are as follows: the fiber surface density is 100 to 200 g / m 2 The hot roller temperature of the hot melt prepreg machine is 75-85°C, the impregnation pressure is 0.3-0.7MPa, the cooling plate temperature is 5-15°C, and the prepreg discharge speed is 2-5m / min.

[0027] The second object of the present invention is to provide a bismaleimide resin prepreg prepared by the above method.

[0028] It is further defined that the bismaleimide resin prepreg has an area density of 150 to 300 g / m 2 The resin content is 30-35%, the gel time is 20-30 minutes at 180°C, and the volatile matter content is less than 1%.

[0029] The third object of the present invention is to provide a high-temperature resistant and high-toughness bismaleimide resin composite material, which is prepared using the above-mentioned bismaleimide resin prepreg.

[0030] It is further defined that the fiber volume content of the bismaleimide resin composite material is 57-63%, the glass transition temperature is 300-320°C, the 90° tensile strength of the unidirectional plate is 45-60 MPa, and the interlaminar shear strength is 95-105 MPa.

[0031] The fourth object of the present invention is to provide a method for preparing a high-temperature resistant and high-toughness bismaleimide resin composite material, which comprises cutting, laying and curing the above-mentioned bismaleimide resin prepreg to obtain a high-temperature resistant and high-toughness bismaleimide resin composite material.

[0032] It is further defined that the curing conditions are (125-135°C) / (2-3h)+(175-185°C) / (3-4h)+(225-235°C) / (2-3h)+(275-285°C) / (2-3h), and the heating rate is 1-3°C / min.

[0033] The beneficial effects of the present invention are as follows:

[0034] The invention adopts two toughening modifiers, namely a diallyl compound and a polyimide, to modify a bismaleimide resin, uses the modified bismaleimide resin and fibers to prepare a prepreg, cuts, lays and cures the prepreg, and prepares a high-temperature resistant and high-toughness bismaleimide resin composite material. The bismaleimide resin prepreg has good processability, low volatile content, and long storage period. The bismaleimide resin composite material has excellent heat resistance and toughness, and has broad application prospects in the field of aerospace.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] (1) The present invention uses a grinder to mix and grind a liquid diallyl compound and a solid powdered polyimide resin. Because the amount of the diallyl compound is greater than the amount of the polyimide resin, under the action of the high shear force of the grinder, the powdered polyimide resin will be evenly dispersed in the diallyl compound and wrapped by the diallyl compound to form a microsphere structure. The two are added to a reactor. As the temperature of the reactor increases, the diallyl compound outside the microsphere will undergo a diene addition reaction with the added bismaleimide resin, thereby changing the molecular chain and the polyimide structure of the bismaleimide resin. The aggregate structure forms a macroscopically uniform and microscopically two-phase structure, which can induce silver streaks and shear bands, causing the material to undergo significant deformation. Due to the synergistic effect of the silver streaks and shear bands and the barrier effect of the polyimide resin inside the microspheres on cracks, the further development of the cracks can be effectively prevented, so that the bismaleimide resin composite material consumes more energy before being destroyed, thereby improving the toughness of the composite material. The polyimide resin used in the present invention is a thermoplastic polyimide, which has excellent heat resistance, so that the bismaleimide resin composite material can achieve the effects of high heat resistance and high toughness at the same time.

[0037] (2) The bismaleimide resin adhesive of the present invention has a simple preparation method, controllable reaction conditions, no small molecules are generated during the reaction, and can be industrially produced. The bismaleimide resin prepreg made of the resin adhesive has good processability at room temperature, a long storage period, a low volatile content, and a simple curing process.

[0038] (3) The bismaleimide resin composite material plate provided by the present invention has high longitudinal tensile strength, good toughness, high interlaminar shear strength, good heat resistance, excellent mechanical properties, high temperature resistance and good toughness, and has broad application prospects in the aerospace field. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0040] In the following description, many specific details are set forth to provide a thorough understanding of the present invention, but the present invention may also be employed.

[0041] Other implementations different from those described herein can be performed by those skilled in the art without violating the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0042] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0043] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by those skilled in the art through commercial channels. The reagents and drugs used in the following examples are all analytically pure.

[0044] Example 1

[0045] Preparation of bismaleimide resin prepreg:

[0046] Step 1: Preparation of bismaleimide resin glue:

[0047] 5000g of diallyl bisphenol A and 1500g of polyimide resin were weighed and stirred at 70℃ and 20r / min. After stirring, they were fully ground and mixed in a three-roll mill. The gap between the rear roller and the front roller in the three-roll mill was 0.02mm, the gap between the middle roller and the front roller was 0.01mm, and the roller speed ratio of the rear roller, the middle roller and the front roller was 1:2.4:4.98. After grinding, the two were added to the reactor. The reactor temperature was set to 90℃, the heating rate was 1℃ / min, the stirring speed was 35r / min, and the dispersion speed was 650r / min. When the temperature of the mixture of diallyl bisphenol A and polyimide resin in the reactor reached At 90°C, 5000g of 4,4-bismaleimide diphenylmethane resin is added to a reactor, and the stirring speed, dispersion speed, temperature and heating rate of the reactor are adjusted to 50r / min, 800r / min, 140°C and 1°C / min, so that the bismaleimide resin and diallyl bisphenol A undergo a prepolymerization reaction under high-speed stirring and dispersion. When the temperature reaches 140°C, the reaction is carried out for 30 minutes. After the reaction is completed, the circulating cooling device of the reactor is turned on, and the resin system in the reactor is cooled to 95°C at a cooling rate of 1°C / min, and the material is discharged to obtain a bismaleimide resin glue, which is stored at -18 to -10°C.

[0048] The polyimide resin used in this embodiment contains Thermoplastic polyimide powder with structure.

[0049] Step 2: Preparation of bismaleimide resin prepreg

[0050] The bismaleimide resin glue prepared in step 1 is processed into a resin glue film by placing the bismaleimide resin glue on a melt frame at 80°C to heat and melt it, setting the coating machine hot roller temperature to 80°C, the cooling plate temperature to 10°C, the coating speed to 10m / min, and adjusting the gap between the hot rollers to make the surface density of the single-sided resin glue film to be 29g / m 2 ;

[0051] The T800 carbon fiber reinforced material is impregnated into the double-sided adhesive film by hot melt method to make prepreg. The temperature of the hot melt prepreg machine hot roller is controlled at 80°C, the impregnation pressure is 0.5MPa, the cooling plate temperature is 10°C, the prepreg discharge speed is controlled at 3m / min, and the carbon fiber surface density is controlled at 106g / m 2 The performance index of the obtained bismaleimide resin prepreg is: surface density is 167g / m 2 , the resin mass content is 35%, the gel time (180℃) is 25min, and the volatile matter content is less than 1%.

[0052] Example 2

[0053] The bismaleimide resin prepreg obtained in Example 1 was cured by a laying process according to a curing system of 130°C / 2h+180°C / 4h+230°C / 3h+280°C / 2h, with a heating rate of 1°C / min, to obtain a high-temperature resistant and high-toughness bismaleimide resin composite material with a thickness of 2 mm and a fiber volume content of 59.38%.

[0054] The high temperature resistant and high toughness bismaleimide resin composite material prepared in this embodiment was tested for room temperature and high temperature mechanical properties using a universal testing machine. The 0° tensile strength and 90° tensile strength were tested according to GB / T3354-2014, the flexural strength was tested according to GB / T 3356-2014, and the interlaminar shear strength was tested according to JC / T 773-2010. The glass transition temperature Tg of the composite material was tested by dynamic thermomechanical analysis (DMA), and the test standard was implemented in accordance with GB / T 40396-2021. The test results are shown in Table 1.

[0055] Table 1 Mechanical properties of bismaleimide resin composites prepared in this example

[0056]

[0057] It can be seen from the data in Table 1 that the tensile properties, bending properties, and interlaminar shear properties of the bismaleimide resin composite material prepared in this embodiment are all high at room temperature, indicating that the composite material has good mechanical properties, especially the 90° tensile strength at room temperature reaches 46.37 MPa, and the composite material has high toughness. By testing the high-temperature mechanical properties of the composite material at 250°C and comparing the retention rate with the room temperature data, it can be seen that the retention rates of various strengths and modulus of the composite material at 250°C are greater than 75%, indicating that the bismaleimide resin composite material prepared in this embodiment has excellent mechanical properties at high temperatures.

[0058] Example 3

[0059] Preparation of bismaleimide resin prepreg:

[0060] Step 1: Preparation of bismaleimide resin glue:

[0061] 5000g of diallyl bisphenol S and 2000g of polyimide resin were weighed, stirred at 75°C and 20r / min, and then fully ground and mixed in a three-roll mill. The gap between the rear roller and the front roller in the three-roll mill was 0.02mm, the gap between the middle roller and the front roller was 0.01mm, and the roller speed ratio of the rear roller, the middle roller and the front roller was 1:2.4:4.98. After grinding, the two were added to the reactor, and the reactor temperature was set to 95°C, the heating rate was 2°C / min, the stirring speed was 40r / min, and the dispersion speed was 680r / min. When the mixture of diallyl bisphenol S and polyimide resin in the reactor was When the temperature of the mixture reaches 95°C, 5000g of 4,4-bismaleimide diphenyl sulfone resin is added to the reactor, and the stirring speed of the reactor is adjusted to 60r / min, the dispersion speed is 900r / min, the temperature is 135°C, and the heating rate is 2°C / min, so that the resin undergoes a prepolymerization reaction under high-speed stirring and dispersion. When the temperature reaches 135°C, the reaction is carried out for 40min. After the reaction is completed, the circulating cooling device of the reactor is turned on, and the resin system in the reactor is cooled to 98°C at a cooling rate of 2°C / min, and the material is discharged to obtain a bismaleimide resin glue, which is stored at -18 to -10°C.

[0062] The polyimide resin used in this embodiment contains Thermoplastic polyimide powder with structure.

[0063] Step 2: Preparation of bismaleimide resin prepreg:

[0064] The bismaleimide resin glue prepared in step 1 is processed into a resin glue film by heating and melting the bismaleimide resin glue on a 75°C melt frame, setting the coating machine hot roller temperature to 85°C, the cooling plate temperature to 12°C, the coating speed to 12m / min, and adjusting the gap between the hot rollers to make the surface density of the single-sided resin glue film to be 29g / m 2 ;

[0065] The T800 carbon fiber reinforced material was impregnated into a double-sided adhesive film by hot melt method to prepare prepreg. The temperature of the hot roll of the hot melt prepreg machine was controlled at 85°C, the impregnation pressure was 0.6MPa, the cooling plate temperature was 12°C, the prepreg discharge speed was controlled at 4m / min, and the carbon fiber surface density was controlled at 106g / m 2 The performance index of the bismaleimide resin carbon fiber prepreg is: surface density is 167g / m 2 , the resin mass content is controlled at 35%, the gel time (180°C) is 25min, and the volatile matter content is less than 1%.

[0066] Example 4

[0067] The bismaleimide resin prepreg obtained in Example 3 was cured by a laying process according to a curing system of 135°C / 3h+185°C / 4h+235°C / 3h+275°C / 3h, with a heating rate of 2°C / min, to obtain a high-temperature resistant and high-toughness bismaleimide resin composite material with a thickness of 2 mm and a fiber volume content of 59.65%.

[0068] The high temperature resistant and high toughness bismaleimide resin composite material prepared in Example 4 was tested for room temperature and high temperature mechanical properties using a universal testing machine. The 0° tensile strength and 90° tensile strength were tested in accordance with GB / T3354-2014, the flexural strength was tested in accordance with GB / T 3356-2014, and the interlaminar shear strength was tested in accordance with JC / T 773-2010. The glass transition temperature Tg of the composite material was tested by dynamic thermomechanical analysis (DMA), and the test standard was implemented in accordance with GB / T 40396-2021. The test results are shown in Table 2.

[0069] Table 2 Mechanical properties of bismaleimide resin composites prepared in this example

[0070]

[0071] It can be seen from the data in Table 2 that the tensile properties, bending properties, and interlaminar shear properties of the bismaleimide resin composite material prepared in this embodiment are all high at room temperature, indicating that the composite material has good mechanical properties, especially the 90° tensile strength at room temperature reaches 52.11 MPa, and the composite material has high toughness. By testing the high-temperature mechanical properties of the composite material at 250°C and comparing the retention rate with the room temperature data, it can be seen that the retention rates of various strengths and modulus of the composite material at 250°C are greater than 75%, indicating that the bismaleimide resin composite material prepared in this embodiment has excellent mechanical properties at high temperatures.

[0072] Example 5

[0073] Preparation method of bismaleimide resin prepreg:

[0074] Step 1: Preparation of bismaleimide resin glue:

[0075] 5000g of bisphenol A bisallyl ether and 2500g of polyimide resin were weighed, stirred at 65°C and 20r / min, and then fully ground and mixed in a three-roll mill. The gap between the rear roller and the front roller in the three-roll mill was 0.02mm, and the gap between the middle roller and the front roller was 0.01mm. The roller speed ratio of the rear roller, the middle roller and the front roller was 1:2.4:4.98. After grinding, the two were added to the reactor. The reactor temperature was set to 85°C, the heating rate was 3°C / min, the stirring speed was 45r / min, and the dispersion speed was 700r / min. When the temperature of the mixture of bisphenol A bisallyl ether and polyimide resin in the reactor reached 85°C, 5000g of 4,4-bismaleimide diphenyl ether resin is added to a reactor, and the stirring speed, dispersion speed, temperature and heating rate of the reactor are adjusted to 65 r / min, 950 r / min, 125°C and 3°C / min, so that the resin undergoes a prepolymerization reaction under high-speed stirring and dispersion. When the temperature reaches 125°C, the reaction is carried out for 55 minutes. After the reaction is completed, the circulating cooling device of the reactor is turned on, and the resin system in the reactor is cooled to 100°C at a cooling rate of 3°C / min, and the material is discharged to obtain a bismaleimide resin glue, which is stored at -18 to -10°C.

[0076] The polyimide resin used in this embodiment contains Thermoplastic polyimide powder with structure.

[0077] Step 2: Preparation of bismaleimide resin prepreg:

[0078] The bismaleimide resin glue prepared in step 1 is processed into a resin glue film by placing the bismaleimide resin glue on a melt frame at 80°C to heat and melt it, setting the coating machine hot roller temperature to 90°C, the cooling plate temperature to 8°C, the coating speed to 15m / min, and adjusting the gap between the hot rollers to make the resin glue film surface density to 29g / m 2 ;

[0079] The T800 carbon fiber reinforced material is impregnated into a double-sided adhesive film by hot melt method to make prepreg. The temperature of the hot roll of the hot melt prepreg machine is controlled at 75°C, the impregnation pressure is 0.7MPa, the cooling plate temperature is 15°C, the discharge speed is controlled at 5m / min, and the carbon fiber surface density is controlled at 106g / m 2 The performance index of the bismaleimide resin carbon fiber prepreg is: surface density is 167g / m 2 , the resin mass content is controlled at 35%, the gel time (180°C) is 25min, and the volatile matter content is less than 1%.

[0080] Example 6

[0081] The bismaleimide resin prepreg obtained in Example 5 was cured by a laying process according to a curing system of 125°C / 2h+175°C / 3h+225°C / 2h+285°C / 3h, with a heating rate of 2°C / min, to obtain a high-temperature resistant and high-toughness bismaleimide resin composite material with a thickness of 2 mm and a fiber volume content of 61.91%.

[0082] The high temperature resistant and high toughness bismaleimide resin composite material prepared in this embodiment was tested for room temperature and high temperature mechanical properties using a universal testing machine. The 0° tensile strength and 90° tensile strength were tested in accordance with GB / T3354-2014, the flexural strength was tested in accordance with GB / T 3356-2014, and the interlaminar shear strength was tested in accordance with JC / T 773-2010. The glass transition temperature Tg of the composite material was tested by dynamic thermomechanical analysis (DMA), and the test standard was implemented in accordance with GB / T 40396-2021. The test results are shown in Table 3.

[0083] Table 3 Mechanical properties of bismaleimide resin composites prepared in this example

[0084]

[0085] It can be seen from the data in Table 3 that the tensile properties, bending properties, and interlaminar shear properties of the bismaleimide resin composite material prepared in this embodiment are all high at room temperature, indicating that the composite material has good mechanical properties, especially the 90° tensile strength at room temperature reaches 56.59 MPa, indicating that the composite material has high toughness. By testing the high-temperature mechanical properties of the composite material at 250°C and comparing the retention rate with the room temperature data, it can be seen that the strength and modulus retention rates of the composite material at 250°C are all greater than 75%, indicating that the bismaleimide resin composite material prepared in this embodiment has excellent mechanical properties at high temperatures.

[0086] Comparative Example 1

[0087] Preparation of bismaleimide resin prepreg:

[0088] Step 1: Preparation of bismaleimide resin glue:

[0089] Weigh 5000g of diallyl bisphenol A and 5000g of 4,4-bismaleimide diphenylmethane and stir at 70°C at a speed of 20r / min. After stirring, fully grind and mix them in a three-roll mill. The gap between the rear roller in the three-roll mill is 0.02mm, the gap between the middle and front rollers is 0.01mm, and the roller speed ratio of the rear roller, the middle roller and the front roller is 1:2.4:4.98. After grinding, add the two into the reactor, set the reactor temperature to 90°C, the heating rate to 1°C / min, the stirring speed to 35r / min, the dispersion speed to 650r / min, and when the diallyl bisphenol A and bismaleimide resin in the reactor are mixed When the material temperature reaches 90°C, the stirring speed of the reactor is adjusted to 50r / min, the dispersion speed is 800r / min, the temperature is 130°C, and the heating rate is 1°C / min, so that the bismaleimide resin and diallyl bisphenol A undergo a prepolymerization reaction under high-speed stirring and dispersion. When the temperature reaches 130°C, the reaction is carried out for 40 minutes. After the reaction is completed, the circulating cooling device of the reactor is turned on, and the resin system in the reactor is cooled to 100°C at a cooling rate of 1°C / min, and the material is discharged to obtain bismaleimide resin glue, which is stored at -18 to -10°C.

[0090] Preparation of bismaleimide resin prepreg:

[0091] Step 2: Preparation of bismaleimide resin prepreg

[0092] The bismaleimide resin glue prepared in step 1 is processed into a resin glue film by placing the bismaleimide resin glue on a melt frame at 80°C to heat and melt it, setting the coating machine hot roller temperature to 80°C, the cooling plate temperature to 10°C, the coating speed to 10m / min, and adjusting the gap between the hot rollers to make the surface density of the single-sided resin glue film to be 29g / m 2 ;

[0093] The T800 carbon fiber reinforced material is impregnated into the double-sided adhesive film by hot melt method to make prepreg. The temperature of the hot melt prepreg machine hot roller is controlled at 80°C, the impregnation pressure is 0.5MPa, the cooling plate temperature is 10°C, the prepreg discharge speed is controlled at 3m / min, and the carbon fiber surface density is controlled at 105g / m 2 The performance index of the obtained bismaleimide resin prepreg is: surface density is 164g / m 2 , the resin content is 32%, the gel time (180℃) is 25min, and the volatile content is less than 1%.

[0094] Comparative Example 2

[0095] The bismaleimide resin prepreg obtained in Comparative Example 1 was cured by a laying process according to a curing system of 130°C / 2h+180°C / 4h+230°C / 3h+280°C / 2h, with a heating rate of 1°C / min, to obtain a high-temperature resistant and high-toughness bismaleimide resin composite material with a thickness of 2 mm and a fiber volume content of 61.65%.

[0096] The high temperature resistant and high toughness bismaleimide resin composite material prepared in this comparative example was tested for room temperature and high temperature mechanical properties using a universal testing machine. The 0° tensile strength and 90° tensile strength were tested in accordance with GB / T3354-2014, the flexural strength was tested in accordance with GB / T 3356-2014, and the interlaminar shear strength was tested in accordance with JC / T 773-2010. The glass transition temperature Tg of the composite material was tested by dynamic thermomechanical analysis (DMA), and the test standard was implemented in accordance with GB / T 40396-2021. The test results are shown in Table 4.

[0097] Table 4 Mechanical properties of bismaleimide resin composites prepared in this comparative example

[0098]

[0099] Comparative Examples 1 and 2 are bismaleimide resin adhesives, prepregs and composite materials prepared by using only diallyl compounds and unheated plastic polyimide powder. As can be seen from the data in Table 4, the glass transition temperature of the bismaleimide resin composite material prepared in this comparative example is 284.36°C, Tg is less than 300°C, the strength retention rate at 250°C is low, and the 90° tensile strength at room temperature is 34.51MPa. Compared with the bismaleimide resin system with added thermoplastic polyimide powder, the composite material prepared by simple bismaleimide and diallyl compounds has poor heat resistance and toughness.

[0100] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a prepreg for a high-temperature resistant and high-toughness bismaleimide resin composite material, characterized in that: include: Step 1: Preparation of bismaleimide resin glue: The diallyl compound and the polyimide resin are weighed, stirred, and ground, and added into a reactor, and the temperature, heating rate, stirring speed, and dispersion speed of the reactor are set. When the reactor reaches the set temperature, the bismaleimide resin is added, and the stirring speed, dispersion speed, and temperature of the reactor are adjusted again. After reacting for a period of time, the reaction is cooled to obtain a bismaleimide resin glue; Step 2: Preparation of bismaleimide resin prepreg: The bismaleimide resin adhesive obtained in step one is processed into a resin adhesive film, and then the fiber is impregnated into the resin adhesive film by a hot melt method to obtain a bismaleimide resin prepreg.

2. The preparation method according to claim 1, characterized in that: In step 1, the diallyl compound is one or more of diallyl bisphenol A, diallyl bisphenol S, and bisphenol A bisallyl ether; the bismaleimide resin is one or more of 4,4-bismaleimide diphenylmethane, 4,4-bismaleimide diphenyl sulfone, 4,4-bismaleimide diphenyl ether, and N,N'-m-phenylene bismaleimide; and the polyimide resin is thermoplastic polyimide micropowder.

3. The preparation method according to claim 1, characterized in that: In step 1, the mass ratio of the diallyl compound to the polyimide resin is (1-5):1; the mass ratio of the sum of the mass of the diallyl compound and the polyimide resin to the bismaleimide resin is (1-2):

1.

4. The preparation method according to claim 1, characterized in that: The method for processing the bismaleimide resin adhesive into a resin adhesive film in step 2 is as follows: placing the bismaleimide resin adhesive on a melt frame at 70-80°C to heat and melt it, setting the coating machine hot roller temperature to 80-90°C, the cooling plate temperature to 5-15°C, the coating speed to 10-15 m / min, and adjusting the gap between the hot rollers to make the resin adhesive film surface density 25-50 g / m 2 ; The parameters of the process of hot-melt impregnation of the fiber into the resin film are: the fiber surface density is 100-200g / m 2 The hot roller temperature of the hot melt prepreg machine is 75-85°C, the impregnation pressure is 0.3-0.7MPa, the cooling plate temperature is 5-15°C, and the discharge speed is 2-5m / min.

5. The preparation method according to claim 2, characterized in that: Thermoplastic polyimide powder includes at least one of the following characteristic structures:

6. A prepreg for a high temperature resistant and high toughness bismaleimide resin composite material, characterized in that: The method is prepared by any one of claims 1 to 5.

7. The prepreg according to claim 6, characterized in that The prepreg surface density is 150-300 g / m 2 The resin content is 30-35%, the gel time is 20-30 minutes at 180°C, and the volatile matter content is less than 1%.

8. A high temperature resistant and high toughness bismaleimide resin composite material, characterized in that: The composite material is prepared by using the prepreg described in any one of claims 6 to 7.

9. The bismaleimide resin composite material according to claim 8, characterized in that: The fiber volume content of the composite material is 57-63%, the glass transition temperature is 300-320°C, the 90° tensile strength of the unidirectional plate is 45-60MPa, and the interlaminar shear strength is 95-105MPa.

10. A method for preparing the bismaleimide resin composite material according to any one of claims 8 to 9, characterized in that: The method cuts, lays and cures the prepreg to obtain a high-temperature resistant and high-toughness bismaleimide resin composite material.

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