Thermosetting polyimide resin containing functionalized boron nitride and preparation method thereof

Abstract

The invention discloses a thermosetting polyimide resin containing functionalized boron nitride and a preparation method thereof, and relates to the technical field of polymer composite materials. The preparation method comprises the following steps: grafting amino groups on the surface of BN through a silane coupling reaction to obtain functionalized BN, then preparing a homogenous slurry formed by mixing the functionalized BN and HBPSi through ultrasonic high-speed shearing, adding the homogenous slurry into a thermosetting polyimide resin solution, and then separating out a BN / PI mixed prepolymer through a physical method; and the thermosetting polyimide resin is prepared by combining a gradient curing process. Through the multi-scale interface design of the functionalized BN nano filler and the thermosetting polyimide, the toughness, thermal conductivity and thermal stability of the material are synergistically improved, and the problems of poor toughness and uneven dispersion of the BN filler of the traditional thermosetting polyimide resin are solved; and the material can well meet the application requirements in the fields of aerospace, electronic packaging and high-precision wear-resistant devices.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to a thermosetting polyimide resin containing functionalized boron nitride and its preparation method. Background Technology

[0002] Thermosetting polyimide (PI) is widely used in aerospace, electronic packaging, and other fields due to its excellent high-temperature resistance, mechanical strength, and dielectric properties. However, traditional thermosetting PI has a high crosslinking density and low impact strength, making it prone to brittle fracture under impact loads. Currently, there are two main toughening technologies: one is to add thermoplastic resins, which, while improving toughness, significantly reduces the heat resistance and dimensional stability of the PI resin; the other method is to modify the resin structure, but this method has excessively high design and development costs and cannot significantly improve the toughness of PI resin.

[0003] In recent years, hexagonal boron nitride (h-BN) has been used in polyimide composites to improve thermal conductivity due to its high thermal conductivity, insulation properties, and two-dimensional lamellar structure. However, the interfacial bonding between h-BN and the polyimide matrix is ​​weak, and it is prone to agglomeration at high filler contents, leading to a decrease in mechanical properties. Therefore, how to achieve a synergistic improvement in the strength and functionalization of thermosetting polyimides through BN interface engineering has become a technical challenge in the industry. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, one of the objectives of this invention is to provide a method for preparing a thermosetting polyimide resin containing functionalized boron nitride. The method involves preparing a homogeneous slurry of functionalized BN and HBPSi by ultrasonic high-speed shearing and adding it to a thermosetting polyimide resin solution to physically precipitate a BN / PI mixed prepolymer. Combined with a gradient curing process, the toughness of the resulting thermosetting polyimide resin is significantly improved.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows: A method for preparing a thermosetting polyimide resin containing functionalized boron nitride includes the following steps: S1. Boron nitride nanosheets were immersed in a mixed solution of 3-aminopropyltriethoxysilane (APTES) and ethanol, and a silane coupling reaction was carried out under reflux to graft amino groups (-NH2) onto the surface of boron nitride (BN). S2. The aminated boron nitride and HBPSi obtained in step S1 are added to a high-boiling-point solvent and dispersed at the nanoscale by ultrasonic high-speed shearing to form a homogeneous slurry. S3. Add the homogeneous slurry obtained in step S2 to the thermosetting polyimide resin solution, heat and stir to react, and form a BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to anhydrous ethanol to precipitate polyimide solid powder. After filtration, wash the polyimide powder with deionized water, vacuum dry to constant weight, and grind to obtain BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is loaded into a closed mold, heated by gradient and then pressure is applied. The mixture is kept at the same temperature and pressure, and then cooled and removed from the mold to obtain the final product.

[0006] In a preferred embodiment of the present invention, the boron nitride nanosheets in step S1 constitute 5-20% of the total weight of the mixed solution, the mixing mass ratio of 3-aminopropyltriethoxysilane to ethanol in the mixed solution of 3-aminopropyltriethoxysilane and ethanol is 1:6-12, and the reflux time is 1-6 h.

[0007] In a preferred embodiment of the present invention, in step S2, the aminated boron nitride accounts for 1-15% of the total solution volume, the HBPSi accounts for 0.5-5% of the total solution volume, and the high-boiling-point solvent accounts for 80-98.5% of the total solution volume. The total solution volume refers to the sum of the mass percentages of the aminated boron nitride, HBPSi, and high-boiling-point solvent, and the sum of the mass percentages of the three is equal to 100%.

[0008] In a preferred embodiment of the present invention, the high-boiling-point solvent in step S2 is selected from at least one of DMF, DMAc or DMSO.

[0009] In a preferred embodiment of the present invention, the ultrasonic frequency of the high-speed ultrasonic shearing in step S2 is 10~100 kHz, the ultrasonic time is 1~3 h, the rotation speed is 5000~10000 rpm, and the stirring time is 20~40 min.

[0010] In a preferred embodiment of the present invention, the mass ratio between the homogeneous slurry and the thermosetting polyimide resin solution in step S3 is 1:6~10.

[0011] In a preferred embodiment of the present invention, the thermosetting polyimide resin in step S3 is a polyimide resin end-capped with one of phenylethynyl phthalic anhydride, norbornene phthalic anhydride, or ethynyl phthalic anhydride, or a polyimide resin containing ethynyl bisphthalic anhydride in its main chain structure.

[0012] In a preferred embodiment of the present invention, the heating temperature for heating and stirring in step S3 is 50~100℃ and the reaction time is 2~6h.

[0013] In a preferred embodiment of the present invention, the amount of anhydrous ethanol used in step S4 is 4 to 8 times the total amount of the BN / PI prepolymer solution, the number of times the deionized water is washed is 3 to 10, and the drying temperature of the vacuum drying is 60 to 200°C, the vacuum degree is -0.05 to -0.1 MPa, and the drying time is 1 to 12 h.

[0014] In a preferred embodiment of the present invention, after the temperature is gradually increased to 150~360 ℃ in step S5, a pressure of 0.5~5 MPa is applied, and then the temperature and pressure are maintained at 300~400 ℃ and 0.5~5 MPa for 1~24 h.

[0015] As a preferred embodiment of the present invention, the gradient heating procedure in step S5 is as follows: after heating to 150~200℃, hold for 1 hour, continue heating to 250~300℃ and hold for 1~4 hours, and finally heat to 340~360℃ and hold for 20~60 minutes.

[0016] A second objective of this invention is to provide a thermosetting polyimide resin containing functionalized boron nitride, which is prepared according to the preparation method described above.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The preparation method of this invention involves preparing a homogeneous slurry of functionalized BN and HBPSi mixture using ultrasonic high-speed shearing. This slurry is then added to a thermosetting polyimide resin solution, and a BN / PI mixed prepolymer is precipitated using physical methods. Combined with a gradient temperature curing process, this effectively improves the toughness and thermal conductivity of the thermosetting polyimide resin without affecting its original heat resistance. Compared to existing technologies, the preparation method of this invention is simple, convenient, and low-cost, and has high versatility, effectively improving the reliability of thermosetting polyimide resins in aerospace, electronic packaging, and high-precision wear-resistant device applications. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments.

[0019] This invention provides a thermosetting polyimide resin containing functionalized boron nitride, which is prepared by the following method, specifically including the following steps: S1. Boron nitride nanosheets are immersed in a mixed solution of 3-aminopropyltriethoxysilane (APTES) and ethanol, and heated under reflux at 80°C for 1-6 h to carry out a silane coupling reaction to graft amino groups (-NH2) onto the surface of boron nitride (BN); wherein, the boron nitride nanosheets account for 5-20% of the total weight of the mixed solution, and the mixing mass ratio of 3-aminopropyltriethoxysilane to ethanol in the mixed solution of 3-aminopropyltriethoxysilane and ethanol is 1:6-12; S2. The aminated boron nitride and HBPSi obtained in step S1 are added to a high-boiling-point solvent and subjected to ultrasonic high-speed shearing under the conditions of ultrasonic frequency of 10~100 kHz, ultrasonic time of 1~3 h, rotation speed of 5000~10000 rpm, and stirring time of 20~40 min to achieve nanoscale dispersion and form a homogeneous slurry; wherein, aminated boron nitride accounts for 1~15% of the total solution volume, HBPSi accounts for 0.5~5% of the total solution volume, and the high-boiling-point solvent accounts for 80~98.5% of the total solution volume; S3. Add the homogeneous slurry obtained in step S2 to the thermosetting polyimide resin solution at a mass ratio of 1:6~10, heat to 50~100℃ and react for 2~6 hours with stirring to form a BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to anhydrous ethanol at a volume of 4 to 8 times the total volume of the BN / PI prepolymer solution to precipitate polyimide solid powder. After filtration, wash the polyimide powder with deionized water 3 to 10 times. Vacuum dry it for 1 to 12 hours at a drying temperature of 60 to 200 °C and a vacuum degree of -0.05 to -0.1 MPa until constant weight. Grind it to obtain the BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is placed into a closed mold. The temperature is gradually increased to 150~360℃, and then a pressure of 0.5~5MPa is applied. The mixture is then held at 300~400℃ and 0.5~5MPa for 1~24 hours. After cooling, the mold is opened and the product is removed. The gradient heating procedure is as follows: heat to 150~200℃ and hold for 1 hour, continue heating to 250~300℃ and hold for 1~4 hours, and finally heat to 340~360℃ and hold for 20~60 minutes.

[0020] In the above preparation method, the high-boiling-point solvent is selected from at least one of DMF, DMAc, or DMSO. The thermosetting polyimide resin is a polyimide resin end-capped with one of phenylethynyl phthalic anhydride, norbornene phthalic anhydride, or ethynyl phthalic anhydride, or a polyimide resin containing ethynyl bisphthalic anhydride in its main chain structure.

[0021] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0022] Example 1 A thermosetting polyimide resin containing functionalized boron nitride is prepared by the following method, which specifically includes the following steps: S1. Immerse 60g of boron nitride nanosheets in 540g of a mixed solution of 3-aminopropyltriethoxysilane and ethanol at a mass ratio of 1:10, and reflux at 80℃ for 4h to carry out a silane coupling reaction to graft amino groups onto the surface of boron nitride. S2. Add 50g of aminated boron nitride and 5g of HBPSi to 445g of DMAc, sonicate at 50kHz for 2 hours, and then shear at 10000rpm for 20 minutes to achieve nanoscale dispersion and form a homogeneous slurry. S3. Add 100g of homogeneous slurry to 900g of thermosetting polyimide resin solution, heat to 70℃ and react for 3h with stirring to form BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to 3000g of anhydrous ethanol to precipitate polyimide solid powder. After filtration, wash the polyimide powder repeatedly with 1000g of deionized water 4 times. Dry it under vacuum at 200℃ and -0.95MPa for 8h until constant weight. Grind it to obtain the BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is placed into a closed mold, heated to 200°C and held for 1 hour, then heated to 250°C and held for 1 hour, then heated to 300°C and held for 1 hour, then heated to 350°C and held for 30 minutes. Then a pressure of 1 MPa is applied, and the temperature is raised to 370°C and held for 1 hour, then raised to 380°C and held for 1 hour. After cooling, the mold is opened and a sample is taken to obtain the final product.

[0023] Example 2 A thermosetting polyimide resin containing functionalized boron nitride is prepared by the following method, which specifically includes the following steps: S1. Immerse 60g of boron nitride nanosheets in 540g of a mixed solution of 3-aminopropyltriethoxysilane and ethanol at a mass ratio of 1:10, and reflux at 80℃ for 4h to carry out a silane coupling reaction to graft amino groups onto the surface of boron nitride. S2. Add 50g of aminated boron nitride and 5g of HBPSi to 445g of DMAc, sonicate at 100kHz for 2 hours, and then shear at 5000rpm for 20 minutes to achieve nanoscale dispersion and form a homogeneous slurry. S3. Add 100g of homogeneous slurry to 900g of thermosetting polyimide resin solution, heat to 70℃ and react for 3h with stirring to form BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to 3000g of anhydrous ethanol to precipitate polyimide solid powder. After filtration, wash the polyimide powder repeatedly with 1000g of deionized water 4 times. Dry it under vacuum at 200℃ and -0.95MPa for 8h until constant weight. Grind it to obtain the BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is placed into a closed mold, heated to 200°C and held for 1 hour, then heated to 250°C and held for 1 hour, then heated to 300°C and held for 1 hour, then heated to 350°C and held for 30 minutes. Then a pressure of 1 MPa is applied, and the temperature is raised to 370°C and held for 1 hour, then raised to 380°C and held for 1 hour. After cooling, the mold is opened and a sample is taken to obtain the final product.

[0024] Example 3 A thermosetting polyimide resin containing functionalized boron nitride is prepared by the following method, which specifically includes the following steps: S1. Immerse 60g of boron nitride nanosheets in 540g of a mixed solution of 3-aminopropyltriethoxysilane and ethanol at a mass ratio of 1:10, and reflux at 80℃ for 4h to carry out a silane coupling reaction to graft amino groups onto the surface of boron nitride. S2. Add 100g of aminated boron nitride and 1g of HBPSi to 399g of DMAc, sonicate at 50kHz for 2 hours, and then shear at 10000rpm for 20 minutes to achieve nanoscale dispersion and form a homogeneous slurry. S3. Add 100g of homogeneous slurry to 900g of thermosetting polyimide resin solution, heat to 70℃ and react for 3h with stirring to form BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to 3000g of anhydrous ethanol to precipitate polyimide solid powder. After filtration, wash the polyimide powder repeatedly with 1000g of deionized water 4 times. Dry it under vacuum at 200℃ and -0.95MPa for 8h until constant weight. Grind it to obtain the BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is placed into a closed mold, heated to 200°C and held for 1 hour, then heated to 250°C and held for 1 hour, then heated to 300°C and held for 1 hour, then heated to 350°C and held for 30 minutes. Then a pressure of 1 MPa is applied, and the temperature is raised to 370°C and held for 1 hour, then raised to 380°C and held for 1 hour. After cooling, the mold is opened and a sample is taken to obtain the final product.

[0025] Example 4 A thermosetting polyimide resin containing functionalized boron nitride is prepared by the following method, which specifically includes the following steps: S1. Immerse 60g of boron nitride nanosheets in 540g of a mixed solution of 3-aminopropyltriethoxysilane and ethanol at a mass ratio of 1:10, and reflux at 80℃ for 4h to carry out a silane coupling reaction to graft amino groups onto the surface of boron nitride. S2. Add 50g of aminated boron nitride and 5g of HBPSi to 445g of DMAc, sonicate at 50kHz for 2 hours, and then shear at 10000rpm for 20 minutes to achieve nanoscale dispersion and form a homogeneous slurry. S3. Add 150g of homogeneous slurry to 850g of thermosetting polyimide resin solution, heat to 70℃ and react for 3h with stirring to form BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to 3000g of anhydrous ethanol to precipitate polyimide solid powder. After filtration, wash the polyimide powder repeatedly with 1000g of deionized water 4 times. Dry it under vacuum at 200℃ and -0.95MPa for 8h until constant weight. Grind it to obtain the BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is placed into a closed mold, heated to 200°C and held for 1 hour, then heated to 250°C and held for 1 hour, then heated to 300°C and held for 1 hour, then heated to 350°C and held for 30 minutes. Then a pressure of 1 MPa is applied, and the temperature is raised to 370°C and held for 1 hour, then raised to 380°C and held for 1 hour. After cooling, the mold is opened and a sample is taken to obtain the final product.

[0026] Example 5 A thermosetting polyimide resin containing functionalized boron nitride is prepared by the following method, which specifically includes the following steps: S1. Immerse 60g of boron nitride nanosheets in 540g of a mixed solution of 3-aminopropyltriethoxysilane and ethanol at a mass ratio of 1:10, and reflux at 80℃ for 4h to carry out a silane coupling reaction to graft amino groups onto the surface of boron nitride. S2. Add 50g of aminated boron nitride and 5g of HBPSi to 445g of DMAc, sonicate at 50kHz for 2 hours, and then shear at 10000rpm for 20 minutes to achieve nanoscale dispersion and form a homogeneous slurry. S3. Add 100g of homogeneous slurry to 900g of thermosetting polyimide resin solution, heat to 70℃ and react for 3h with stirring to form BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to 3000g of anhydrous ethanol to precipitate polyimide solid powder. After filtration, wash the polyimide powder repeatedly with 1000g of deionized water 4 times. Dry it under vacuum at 200℃ and -0.95MPa for 8h until constant weight. Grind it to obtain the BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is placed into a closed mold, heated to 150°C and held for 2 hours, then heated to 300°C and held for 1 hour, then heated to 360°C and held for 15 minutes, then a pressure of 2 MPa is applied, then heated to 370°C and held for 1 hour, then heated to 380°C and held for 1 hour, then cooled and the mold is opened to take a sample, which is the final product.

[0027] Comparative Example 1 A thermosetting polyimide resin is prepared by the following method, which specifically includes the following steps: A1. Pour 1000g of thermosetting polyimide resin solution into 3000g of anhydrous ethanol to precipitate solid powder. After filtration, wash the polyimide powder with 1000g of deionized water. Repeat the washing 4 times. Dry under vacuum at 200℃ for 8 hours. Grind to obtain PI prepolymer.

[0028] A2. The PI prepolymer obtained in step A1 is placed into a closed mold, heated to 200°C and held for 1 hour, then heated to 250°C and held for 1 hour, then heated to 300°C and held for 1 hour, then heated to 350°C and held for 30 minutes. Then a pressure of 1 MPa is applied, and the temperature is raised to 370°C and held for 1 hour, then raised to 380°C and held for 1 hour. After cooling, the mold is opened and a sample is taken to obtain the final product.

[0029] Comparative Example 2 A thermosetting polyimide resin is prepared by the following method, which specifically includes the following steps: A1. Add 50g of boron nitride to 450g of DMAc and stir at high speed to form a homogeneous slurry; A2. Add 150g of homogeneous slurry to 850g of thermosetting polyimide resin solution, heat to 70℃ and react for 3h with stirring to form BN / PI mixed solution; A3. Pour 1000g of thermosetting polyimide resin solution into 3000g of anhydrous ethanol to precipitate solid powder. After filtration, wash the polyimide powder with 1000g of deionized water. Repeat the washing 4 times. Dry under vacuum at 200℃ for 8 hours. Grind to obtain PI prepolymer.

[0030] A4. The PI prepolymer obtained in step A1 is placed into a closed mold, heated to 200°C and held for 1 hour, then heated to 250°C and held for 1 hour, then heated to 300°C and held for 1 hour, then heated to 350°C and held for 30 minutes. Then a pressure of 1 MPa is applied, and the temperature is raised to 370°C and held for 1 hour, then raised to 380°C and held for 1 hour. After cooling, the mold is opened and a sample is taken to obtain the final product.

[0031] I. Performance Testing of Thermosetting Polyimide Composites Impact strength, thermal conductivity, thermal weight loss and glass transition temperature of the polyimide resin castings prepared in Examples 1-5 and Comparative Examples 1-2 were tested, and the results are shown in Table 1.

[0032]

[0033] As shown in Table 1, all polyimide resin castings from formulations 1 to 5 incorporated aminated BN. Their impact strength increased by 68%–111% compared to Comparative Example 1 (without modified BN) and by 113%–167% compared to Comparative Example 2 (with BN). This is mainly due to the hyperbranched structure of HBPSi interpenetrating between BN layers, forming a rigid-flexible interpenetrating network between the polyimide resins. This network dissipates impact energy, thereby improving the toughness of the thermosetting polyimide resin. Furthermore, its thermal conductivity was significantly higher than that of the unmodified BN. The modified BN in Comparative Example 1 increased thermal conductivity by 2-3 times, and by 2-3 times compared to Comparative Example 2 with BN. This is because the surface of boron nitride was modified by amylation, which improved the compatibility of polyimide, reduced interfacial thermal resistance, and thus improved thermal conductivity. The 5% thermal weight loss temperature was 6-10°C higher than that in Comparative Example 1 without BN, which can improve the thermal stability of the resin matrix to a certain extent. Its glass transition temperature was basically consistent with that of Comparative Example 1, indicating that the addition of BN does not have any adverse effect on the heat resistance of the resin.

[0034] Therefore, the thermosetting polyimide resin prepared by the method of the present invention not only improves the thermal conductivity of the matrix, but more importantly, enhances the toughness of the resin matrix while maintaining the original heat resistance of the resin.

[0035] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a thermosetting polyimide resin containing functionalized boron nitride, characterized in that: Includes the following steps: S1. Boron nitride nanosheets are immersed in a mixed solution of 3-aminopropyltriethoxysilane and ethanol, and a silane coupling reaction is carried out under reflux to graft amino groups onto the surface of boron nitride. S2. The aminated boron nitride and HBPSi obtained in step S1 are added to a high-boiling-point solvent and dispersed at the nanoscale by ultrasonic high-speed shearing to form a homogeneous slurry. S3. Add the homogeneous slurry obtained in step S2 to the thermosetting polyimide resin solution, heat and stir to react, and form a BN / PI mixed solution. S4. Add the BN / PI mixed solution obtained in step S3 to anhydrous ethanol to precipitate polyimide solid powder. After filtration, wash the polyimide powder with deionized water, vacuum dry to constant weight, and grind to obtain BN / PI mixed prepolymer. S5. The BN / PI mixed prepolymer obtained in step S4 is loaded into a closed mold, heated by gradient and then pressure is applied. The mixture is kept at the same temperature and pressure, and then cooled and removed from the mold to obtain the final product.

2. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1, characterized in that: In step S1, the boron nitride nanosheets constitute 5-20% of the total weight of the mixed solution, and the mass ratio of 3-aminopropyltriethoxysilane to ethanol in the mixed solution of 3-aminopropyltriethoxysilane and ethanol is 1:6-12; the reflux time is 1-6 h.

3. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1, characterized in that: In step S2, the aminated boron nitride accounts for 1-15% of the total solution volume, and the HBPSi accounts for 0.5-5% of the total solution volume; the high-boiling solvent is selected from at least one of DMF, DMAc, or DMSO.

4. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1, characterized in that: The ultrasonic high-speed shearing in step S2 has an ultrasonic frequency of 10~100kHz, an ultrasonic time of 1~3h, a rotation speed of 5000~10000rpm, and a stirring time of 20~40min.

5. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1, characterized in that: In step S3, the mass ratio between the homogeneous slurry and the thermosetting polyimide resin solution is 1:6~10; the heating temperature for heating and stirring is 50~100℃, and the reaction time is 2~6h.

6. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1, characterized in that: The thermosetting polyimide resin mentioned in step S3 is a polyimide resin end-capped with one of phenylethynyl phthalic anhydride, norbornene phthalic anhydride, or ethynyl phthalic anhydride, or a polyimide resin containing ethynyl bisphthalic anhydride in its main chain structure.

7. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1, characterized in that: In step S4, the amount of anhydrous ethanol used is 4 to 8 times the total amount of the BN / PI prepolymer solution, the number of times the deionized water is washed is 3 to 10, and the drying temperature of the vacuum drying is 60 to 200°C, the vacuum degree is -0.05 to -0.1 MPa, and the drying time is 1 to 12 hours.

8. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1, characterized in that: In step S5, after the temperature is gradually increased to 150~360℃, a pressure of 0.5~5MPa is applied, and then the temperature and pressure are maintained at 300~400℃ and 0.5~5MPa for 1~24h.

9. The method for preparing the thermosetting polyimide resin containing functionalized boron nitride according to claim 1 or 8, characterized in that: The gradient temperature procedure in step S5 is as follows: after heating to 150~200℃, hold for 1 hour, continue heating to 250~300℃ and hold for 1~4 hours, and finally heat to 340~360℃ and hold for 20~60 minutes.

10. A thermosetting polyimide resin containing functionalized boron nitride, characterized in that: It is prepared according to the preparation method described in any one of claims 1 to 9.

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