Preparation method of bismaleimide triazine resin composite material containing modified filler

Abstract

The invention relates to material science, and aims to provide a preparation method of a bismaleimide triazine resin composite material containing modified filler. Comprising the following steps: carrying out self-assembly on transition metal nitrate and imidazole ligands to obtain a porous nano material ZIFs with a three-dimensional structure; then reacting with ethyl silicate under a heating condition to obtain a porous nano material coated with a SiO2 shell layer; carrying out a reaction with a pre-hydrolyzed silane coupling agent so as to obtain silane coupling agent graft modified nano powder; the preparation method comprises the following steps: by taking bismaleimide resin and cyanate ester resin as matrixes and the modified nano powder as filler, removing an organic solvent and bubbles after prepolymerization, and curing to obtain the bismaleimide triazine resin composite material containing the modified nano filler. The prepared composite material has the advantages of low dielectric loss, low dielectric constant, high thermal decomposition temperature and high glass transition temperature; and the preparation process is simple, high in repeatability and suitable for industrial mass production.

Description

Technical Field

[0001] The present invention relates to a bismaleimide triazine resin composite material containing modified ZIFs@SiO2 nanofiller and a preparation method thereof. The product is suitable for the integrated circuit electronic packaging industry and belongs to the field of materials science and engineering. Background Art

[0002] In the field of integrated circuit electronic packaging materials, chip packaging substrates connect the chip to the PCB and provide physical protection for the packaged chip. They have significant application markets in consumer electronics, communications, automotive electronics, industrial control, and military aerospace. As chip signal transmission frequency bands and device integration increase, higher requirements are placed on the dielectric properties, thermal stability, and process adaptability of the resin used in packaging substrates. Bismaleimide triazine resin, a high-performance thermosetting resin with low dielectric constant, low dielectric loss, and high thermal stability, has been widely used. However, due to inherent structural limitations of bismaleimide triazine resin, its high crosslink density results in a narrow thermal processing window and high molding temperatures during molding. This results in higher hot pressing and curing temperatures during processing, increasing industrial production costs. In high-frequency applications, bismaleimide triazine resin also exhibits a high dielectric constant and dielectric loss, which impacts device signal transmission speed and the integrity of the transmitted data. In order to meet the demand for higher performance, it is usually necessary to change the resin composition of the bismaleimide triazine resin or the type of high-performance reinforcement.

[0003] The introduction of high-performance nanofillers provides a solution to the problems related to bismaleimide triazine resins in current high-frequency applications. However, the existing filler system still has certain shortcomings in terms of catalytic regulation of the comprehensive performance of the resin, interface bonding, and dispersibility. In high-frequency application scenarios, it has disadvantages such as high dielectric constant and dielectric loss, poor viscous flow processability, and high curing temperature, resulting in limited improvement in the processing performance of actual bismaleimide triazine resin composites.

[0004] Therefore, there is an urgent need to develop a nanofiller that can not only promote the catalytic polymerization of bismaleimide triazine resin but also improve the interfacial bonding state between resin fillers, and its application in composite materials is of great significance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a bismaleimide triazine resin composite material containing a modified filler, specifically a bismaleimide triazine resin composite material containing a modified ZIFs@SiO2 nanofiller.

[0006] In order to solve the technical problem, the present invention adopts the following technical solutions:

[0007] Provided is a method for preparing a bismaleimide-triazine resin composite material containing a modified filler, comprising the steps of:

[0008] (1) Dissolving a transition metal nitrate hydrate and an imidazole ligand in deionized water, and performing a self-assembly reaction under ultrasonic dispersion and stirring conditions; and obtaining a porous nanomaterial ZIFs with a three-dimensional structure after centrifugal washing and drying.

[0009] (2) The porous nanomaterial ZIFs and a surfactant are added to ethanol, the pH value is adjusted to alkaline, and a suspension is obtained by ultrasonic dispersion; an ethanol solution of ethyl silicate (TEOS) is added dropwise to the suspension, and the suspension is continuously stirred under heating conditions to obtain an emulsion; the solid product after centrifugation is washed and dried to obtain a porous nanomaterial ZIFs@SiO2 coated with a SiO2 shell;

[0010] (3) pre-hydrolyzing the silane coupling agent, and then adding it together with the porous nanomaterial ZIFs@SiO2 into an ethanol solution, and continuously stirring under heating conditions after ultrasonic dispersion to obtain a suspension; centrifuging and drying to obtain a nano ZIFs@SiO2 powder grafted with the silane coupling agent;

[0011] (4) adding the bismaleimide resin and cyanate resin as the matrix into an organic solvent and stirring until clear and transparent; then adding the modified nano ZIFs@SiO2 powder as filler and ultrasonically dispersing it uniformly to obtain a transparent solution;

[0012] (5) The transparent solution is continuously stirred under heating conditions for prepolymerization, and the color of the solution changes from light to dark; then it is moved to a vacuum oven, and the organic solvent and bubbles are removed under vacuum and heating conditions. After taking it out, it is poured into a mold and cured. After demolding, a bismaleimide triazine resin composite material containing modified ZIFs@SiO2 nanofiller is obtained.

[0013] As a preferred solution of the present invention, in step (1), ultrasonic dispersion is first performed for 5 to 10 minutes at room temperature, and then magnetic stirring is performed for 20 to 30 minutes to complete the self-assembly reaction.

[0014] As a preferred embodiment of the present invention, in step (1), the transition metal nitrate hydrate is zinc nitrate hexahydrate, and the imidazole ligand is 2-methylimidazole; the molar ratio of the transition metal nitrate hydrate, the imidazole ligand and deionized water is 1:70-75:1400-1500.

[0015] As a preferred embodiment of the present invention, in step (2), the surfactant is hexadecyltrimethylammonium bromide; the mass ratio of the porous nanomaterial ZIFs to the surfactant is 4:5; the mass ratio of the total mass of ZIFs and the surfactant to ethanol is 1:30-40; in the TEOS ethanol solution, the volume ratio of TEOS to ethanol is 1:4-5; and the amount of TEOS ethanol solution added is controlled so that the mass ratio of TEOS to ZIFs in the mixed solution is 4.5-5:1.

[0016] As a preferred embodiment of the present invention, in step (2), ammonia water is used to adjust the pH value to between 11 and 11.6; ultrasonic dispersion is performed for 10 to 15 minutes to obtain a suspension; and magnetic stirring is performed at 50° C. for 18 to 24 hours to obtain an emulsion.

[0017] As a preferred embodiment of the present invention, in step (3), the silane coupling agent is γ-methacryloxypropyltrimethoxysilane (KH570); the mass fraction of the ethanol solution is 95wt%, and it is prepared with deionized water and anhydrous ethanol; the mass ratio of the pre-hydrolyzed silane coupling agent to ZIFs@SiO2 is 1:20-25, and the mass ratio of the total mass of the two to the 95wt% ethanol solution is 1:80-100.

[0018] As a preferred solution of the present invention, in step (3), after ultrasonic dispersion for 10 to 20 minutes, the mixed solution is transferred to a constant temperature water bath at 40 to 55° C. and stirred for 16 to 24 hours to obtain a suspension.

[0019] As a preferred embodiment of the present invention, in step (4), the bismaleimide resin is 4,4'-diaminodiphenylmethane bismaleimide, and the cyanate resin is bisphenol A cyanate; the organic solvent is any one of acetone, 2-butanone or N-N dimethylformamide; the mass ratio of the bismaleimide resin to the cyanate resin is 1:3, the filler powder accounts for 1% to 3% of the total mass of the resin matrix, and the ratio of the total mass of the three to the mass of the organic solvent is 1:1.

[0020] As a preferred solution of the present invention, in step (4), the ultrasonic dispersion time is 10 to 15 minutes.

[0021] As a preferred embodiment of the present invention, in step (5), during the prepolymerization of the transparent solution, the heating temperature is 115-125°C, and the stirring is continued for 25-35 minutes; in a vacuum oven, the vacuum degree is -0.085 MPa, the temperature is 80-110°C, and the drying time is 2 hours; the mold is made of polytetrafluoroethylene; the staged heating and heat preservation curing treatment is carried out in a blast oven, and the curing is carried out at 160°C for 2 hours, 180°C for 2 hours, 200°C for 2 hours, 220°C for 2 hours, and 230°C for 4 hours in sequence; the obtained composite material is a thin film material with a thickness between 650 and 800 μm.

[0022] Description of the invention principle:

[0023] The product obtained by the preparation method of the present invention comprises a matrix resin formed by the polymerization of bismaleimide and cyanate ester, and a ZIFs@SiO2 nanofiller modified with a silane coupling agent. The ZIFs material is a porous nanomaterial with a three-dimensional structure assembled by coordination bonds between transition metal ions and imidazolate organic ligands in an aqueous solvent synthesis system. The ZIFs are coated with a SiO2 shell, and the silane coupling agent is grafted onto the outermost layer.

[0024] This invention prepares a core-shell ZIFs@SiO2 composite in an aqueous solvent system. The ZIFs@SiO2 composite is modified by grafting a silane coupling agent, improving the interfacial compatibility between the nanofiller and the bismaleimide triazine resin, as well as the dispersibility of the particles. The core-shell design enables a slow and uniform catalytic effect on bismaleimide and cyanate resins. The unique pore structure of the silica shell constrains the release of catalytic ions within the composite and protects the morphology and function of the ZIF catalytic core under high temperature, high pressure, or high humidity conditions. It also provides a stable substrate for the grafting of the silane coupling agent, thereby improving the compatibility between the organic and inorganic interfaces and the dispersibility of the filler particles. The transition metal ions within the ZIFs catalyze the crosslinking reaction of the resin, enhancing the crosslinking uniformity and particle stability during the resin preparation process. Therefore, the invention significantly improves the performance of the matrix resin with only a minimal addition of nanofiller, enhancing the dielectric properties of the composite material while maintaining high thermal stability and thermal processability.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The process of preparing a composite material by modifying the nano ZIFs@SiO2 filler with the bismaleimide triazine resin of the present invention by adding a silane coupling agent has a large temperature range and processing time range for viscous flow processing, and the prepared composite material has the advantages of low dielectric loss, low dielectric constant, high thermal decomposition temperature, and high glass transition temperature.

[0027] 2. The present invention innovatively uses silane coupling agent-modified nano-ZIFs@SiO2 as filler, with a simple preparation process and high repeatability. The low-temperature hydrothermal synthesis method is suitable for industrial mass production.

[0028] 3. The present invention only requires a small amount of nanofiller to be added to prepare a bismaleimide triazine resin composite material with excellent dielectric properties and thermal and thermal processing properties, which is suitable for the integrated circuit electronic packaging industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 TEM images of ZIFs and ZIFs@SiO2 nanofillers of the present invention, (a) is the TEM image of ZIFs, and (b) is the TEM image of ZIFs@SiO2.

[0030] Figure 2 The crystallization phenomenon of the samples in the comparative example of the present invention and the examples after being placed for 0-10 minutes after prepolymerization is compared.

[0031] Figure 3 The DSC comparison chart of the comparative example and the example sample after prepolymerization of the present invention is shown in FIG.

[0032] Figure 4 The cross-sectional SEM images of the comparative example and example sample products of the present invention are shown in FIG. (a) to (d) correspond to the comparative example and examples 1 to 3, respectively.

[0033] Figure 5 It is a TGA comparison chart of the products of comparative example and embodiment of the present invention.

[0034] Figure 6 DMA comparison chart of the comparative example and the example product of the present invention.

[0035] Figure 7 The figure is a comparison chart of the dielectric properties of the products of the comparative example and the embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail with reference to the following embodiments, but these embodiments are not intended to limit the scope of the present invention.

[0037] 1. Overview of the implementation scheme of the present invention

[0038] The method for preparing a bismaleimide-triazine resin composite material containing a modified filler provided by the present invention comprises the steps of:

[0039] (1) At room temperature, a transition metal nitrate hydrate and an imidazole ligand are dissolved in deionized water, first dispersed by ultrasonication for 5-10 minutes, and then stirred magnetically for 20-30 minutes to complete the self-assembly reaction. The resulting porous nanomaterials (ZIFs) with a three-dimensional structure are then washed by centrifugation and dried.

[0040] As an optional example, the transition metal nitrate hydrate is zinc nitrate hexahydrate, and the imidazole ligand is 2-methylimidazole; the molar ratio of the transition metal nitrate hydrate, the imidazole ligand and the deionized water is 1:70-75:1400-1500.

[0041] (2) The porous nanomaterial ZIFs and a surfactant were added to ethanol, and the pH value was adjusted to between 11 and 11.6 using ammonia water. After ultrasonic dispersion for 10 to 15 minutes, a uniformly dispersed suspension was obtained. An ethanol solution containing ethyl silicate (TEOS) was added dropwise to the suspension, and magnetic stirring was performed at 50°C for 18 to 24 hours to obtain an emulsion. The solid product after centrifugation was washed and dried to obtain a porous nanomaterial ZIFs@SiO2 coated with a SiO2 shell.

[0042] As an optional example, the surfactant is cetyltrimethylammonium bromide (CTAB); the mass ratio of the porous nanomaterial ZIFs to the surfactant is 4:5; the mass ratio of the total mass of ZIFs and the surfactant to ethanol is 1:30-40; in the ethanol solution of TEOS, the volume ratio of TEOS to ethanol is 1:4-5; the amount of TEOS ethanol solution added is controlled so that the mass ratio of TEOS to ZIFs in the mixed solution is 4.5-5:1.

[0043] (3) The silane coupling agent is pre-hydrolyzed and then added to an ethanol solution together with the porous nanomaterial ZIFs@SiO2. After ultrasonic dispersion for 10 to 20 minutes, the mixed solution is transferred to a constant temperature water bath at 40 to 55°C and stirred for 16 to 24 hours to obtain a suspension. The solid after centrifugation is transferred to a blast oven for drying to obtain a nano ZIFs@SiO2 powder grafted with a silane coupling agent.

[0044] As an optional example, the silane coupling agent is γ-methacryloxypropyltrimethoxysilane (KH570); the mass fraction of the ethanol solution is 95wt%, which is prepared with deionized water and anhydrous ethanol; the mass ratio of the pre-hydrolyzed silane coupling agent to ZIFs@SiO2 is 1:20-25, and the mass ratio of the total mass of the two to the 95wt% ethanol solution is 1:80-100.

[0045] (4) Adding the bismaleimide resin and cyanate resin as the matrix into the organic solvent and stirring until clear and transparent; then adding the modified nano ZIFs@SiO2 powder as filler and ultrasonically dispersing for 10 to 15 minutes to obtain a uniform transparent solution;

[0046] As an optional example, the bismaleimide resin is 4,4'-diaminodiphenylmethane bismaleimide, and the cyanate ester resin is bisphenol A cyanate ester; the organic solvent is any one of acetone, 2-butanone or NN dimethylformamide; the mass ratio of the bismaleimide resin to the cyanate ester resin is 1:3, the filler powder accounts for 1% to 3% of the total mass of the resin matrix, and the ratio of the total mass of the three to the mass of the organic solvent is 1:1.

[0047] (5) The transparent solution was stirred continuously at 115-125°C for 25-35 minutes for prepolymerization, and the color of the solution changed from light to dark; then it was moved to a vacuum oven, the vacuum degree was controlled at -0.085MPa, the temperature was 80-110°C, and it was kept for 2 hours to remove the organic solvent and bubbles; after taking it out, it was poured into a mold and moved to a blast oven for staged heating and heat preservation curing treatment, specifically, it was carried out in a blast oven, and cured at 160°C for 2 hours, 180°C for 2 hours, 200°C for 2 hours, 220°C for 2 hours, and 230°C for 4 hours in sequence; after demolding, a bismaleimide triazine resin composite material containing modified ZIFs@SiO2 nanofiller was obtained.

[0048] As an optional example, the mold is made of polytetrafluoroethylene; the obtained composite material is a thin film material with a thickness between 650 and 800 μm.

[0049] 2. Examples and Comparative Examples

[0050] Example 1:

[0051] Step (1): Dissolve zinc nitrate hexahydrate and 2-methylimidazole in deionized water at room temperature, sonicate for 7 minutes, and stir for 25 minutes to complete the self-assembly reaction. The molar ratio of zinc nitrate hexahydrate, 2-methylimidazole, and deionized water is 1:

[0052] The reaction product was then collected by centrifugation, washed twice with deionized water, and dried in a forced-air oven. The centrifugation parameters were set at 8000 rpm for 25 minutes, and the forced-air oven drying parameters were set at 60°C for 24 hours. Finally, a porous nanomaterial with a three-dimensional structure, ZIF-8, was obtained.

[0053] Step (2): CTAB and the ZIF-8 obtained in step (1) were added to ethanol, and the pH of the solution was adjusted to 11 with aqueous ammonia, and ultrasonicated for 10 minutes to obtain a uniformly dispersed suspension. The mass ratio of ZIF-8 to CTAB was 4:5, and the mass ratio of the total mass of ZIFs and surfactant to ethanol was 1:30.

[0054] Step (3): Add the ethanol solution containing TEOS dropwise to the suspension of step (2), and stir magnetically in a 50°C water bath for 24 hours to obtain an emulsion. The volume ratio of TEOS to anhydrous ethanol is 1:4, and the amount of TEOS ethanol solution added is controlled so that the mass ratio of TEOS to ZIFs in the mixed solution is 4.5:1. The obtained emulsion is centrifuged and washed three times with a mixed solution of deionized water and ethanol in a volume ratio of 1:1 to obtain ZIF-8@SiO2, which is then placed in a blast oven for drying. The centrifugation process parameters of step (3) are set to a centrifugal speed of 8000 rpm and a centrifugal time of 30 minutes; the blast oven drying parameters are set to a temperature of 60°C and a drying time of 24 hours.

[0055] Step (4): Deionized water and anhydrous ethanol were used to prepare a 95 wt% ethanol solution. The ZIF-8@SiO2 obtained in step (3) and the pre-hydrolyzed KH570 silane coupling agent were slowly added to the ethanol solution and ultrasonically dispersed for 10 minutes. The solution was stirred in a 55°C constant temperature water bath for 16 hours, centrifuged, and washed three times with a mixed solution of deionized water and ethanol in a volume ratio of 1:1 to obtain KH570-ZIF-8@SiO2, which was then placed in a blast oven for drying. The mass ratio of ZIF-8@SiO2 to the pre-hydrolyzed KH570 silane coupling agent was 20:1, and the total mass ratio of the two to the 95 wt% ethanol solution was 1:80. The centrifugal process parameters were set as a centrifugal speed of 8000 rpm and a centrifugal time of 25 minutes; the blast oven drying parameters were set as a temperature of 65°C and a drying time of 20 hours.

[0056] Step (5): Add the bismaleimide and cyanate ester and the KH570-ZIF-8@SiO2 filler obtained in step (4) to a beaker containing acetone, ultrasonically disperse for 12 minutes, and stir until the solution becomes clear and transparent. The mass ratio of bismaleimide to cyanate ester is 1:3, the mass of KH570-ZIF-8@SiO2 accounts for 1% of the total mass of bismaleimide and cyanate ester, and the mass ratio of the total mass of bismaleimide, cyanate ester, and KH570-ZIF-8@SiO2 powder to acetone is 1:1.

[0057] Step (6): The beaker containing the transparent solution obtained in step (5) was stirred on a heated stirring table at 115° C. for 35 min to evaporate the acetone solvent until the color of the solution changed from light to dark.

[0058] Step (7): The solution obtained after the prepolymerization by heating and stirring in step (6) was placed in a vacuum oven to remove the acetone solvent and air bubbles, and then poured into a polytetrafluoroethylene mold. The parameters for the vacuum oven solvent removal were set at a temperature of 80°C, a vacuum degree of -0.085 MPa, and a solvent removal time of 2 hours.

[0059] Step (8): pouring the prepolymer solution obtained in step (7) into a polytetrafluoroethylene mold, transferring the mold containing the prepolymer to a blast oven for staged heating and heat preservation curing treatment, that is, curing at 160°C for 2h, 180°C for 2h, 200°C for 2h, 220°C for 2h, and 230°C for 4h in sequence to obtain bismaleimide triazine resin, and the prepared composite material is a thin film material with a thickness of 800μm.

[0060] Example 2:

[0061] Step (1): Dissolve zinc nitrate hexahydrate and 2-methylimidazole in deionized water at room temperature, sonicate for 5 minutes, and stir for 30 minutes to complete the self-assembly reaction. The molar ratio of zinc nitrate hexahydrate, 2-methylimidazole, and deionized water is 1:70:1400. The reaction product is then collected by centrifugation, washed twice with deionized water, and placed in a blast oven for drying. The centrifugal process setting parameters are a centrifugal speed of 8000 rpm and a centrifugal time of 25 minutes; the blast oven drying setting parameters are a temperature of 60°C and a drying time of 24 hours. Finally, a porous nanomaterial ZIF-8 with a three-dimensional structure is obtained.

[0062] Step (2): CTAB and the ZIF-8 obtained in step (1) were added to ethanol, and the pH of the solution was adjusted to 11.6 with aqueous ammonia, and ultrasonicated for 15 minutes to obtain a uniformly dispersed suspension. The mass ratio of ZIF-8 to CTAB was 4:5, and the mass ratio of the total mass of ZIFs and surfactant to ethanol was 1:40.

[0063] Step (3): Add the ethanol solution containing TEOS dropwise to the suspension of step (2), and stir magnetically in a 50°C water bath for 18 hours to obtain an emulsion. The volume ratio of TEOS to anhydrous ethanol is 1:5, and the amount of TEOS ethanol solution added is controlled so that the mass ratio of TEOS to ZIFs in the mixed solution is 5:1. The obtained emulsion is centrifuged and washed three times with a mixed solution of deionized water and ethanol in a volume ratio of 1:1 to obtain ZIF-8@SiO2, which is then placed in a blast oven for drying. The centrifugation process parameters of step (3) are set to a centrifugal speed of 8000 rpm and a centrifugal time of 30 minutes; the blast oven drying parameters are set to a temperature of 60°C and a drying time of 24 hours.

[0064] Step (4): Deionized water and anhydrous ethanol were used to prepare a 95 wt% ethanol solution. The ZIF-8@SiO2 obtained in step (3) and the pre-hydrolyzed KH570 silane coupling agent were slowly added to the ethanol solution and ultrasonically dispersed for 20 minutes. The solution was stirred in a 50°C constant temperature water bath for 20 hours, centrifuged, and washed three times with a mixed solution of deionized water and ethanol in a volume ratio of 1:1 to obtain KH570-ZIF-8@SiO2, which was then placed in a blast oven for drying. The mass ratio of ZIF-8@SiO2 to the pre-hydrolyzed KH570 silane coupling agent was 23:1, and the total mass ratio of the two to the 95 wt% ethanol solution was 1:90. The centrifugal process parameters were set as a centrifugal speed of 8000 rpm and a centrifugal time of 25 minutes; the blast oven drying parameters were set as a temperature of 65°C and a drying time of 20 hours.

[0065] Step (5): Add the bismaleimide and cyanate ester and the KH570-ZIF-8@SiO2 filler obtained in step (4) to a beaker containing 2-butanone, ultrasonically disperse for 15 minutes, and stir until the solution becomes clear and transparent. The mass ratio of bismaleimide to cyanate ester is 1:3, the mass of KH570-ZIF-8@SiO2 accounts for 2% of the total mass of bismaleimide and cyanate ester, and the mass ratio of the total mass of bismaleimide, cyanate ester, and KH570-ZIF-8@SiO2 powder to 2-butanone is 1:1.

[0066] Step (6): The beaker containing the transparent solution obtained in step (5) was stirred on a heated stirring platform at 120° C. for 30 min to evaporate the 2-butanone solvent until the color of the solution changed from light to dark.

[0067] Step (7): The solution obtained after the prepolymerization by heating and stirring in step (6) was placed in a vacuum oven to remove the 2-butanone solvent and air bubbles, and then poured into a polytetrafluoroethylene mold. The parameters for the vacuum oven solvent removal were set at a temperature of 95°C, a vacuum of -0.085 MPa, and a solvent removal time of 2 hours.

[0068] Step (8): Pour the prepolymer solution obtained in step (7) into a polytetrafluoroethylene mold, transfer the mold containing the prepolymer to a blast oven for staged heating and heat preservation curing treatment, that is, curing at 160°C for 2h, 180°C for 2h, 200°C for 2h, 220°C for 2h, and 230°C for 4h in sequence to obtain bismaleimide triazine resin, and the prepared composite material is a thin film material with a thickness of 650μm.

[0069] Example 3:

[0070] Step (1): Dissolve zinc nitrate hexahydrate and 2-methylimidazole in deionized water at room temperature, sonicate for 10 minutes, and stir for 20 minutes to complete the self-assembly reaction. The molar ratio of zinc nitrate hexahydrate, 2-methylimidazole, and deionized water is 1:75:1500. The reaction product is then collected by centrifugation, washed twice with deionized water, and placed in a blast oven for drying. The centrifugal process setting parameters are a centrifugal speed of 8000 rpm and a centrifugal time of 25 minutes; the blast oven drying setting parameters are a temperature of 60°C and a drying time of 24 hours. Finally, a porous nanomaterial ZIF-8 with a three-dimensional structure is obtained.

[0071] Step (2): CTAB and the ZIF-8 obtained in step (1) were added to ethanol, and the pH of the solution was adjusted to 11.2 with aqueous ammonia, and ultrasonicated for 12 minutes to obtain a uniformly dispersed suspension. The mass ratio of ZIF-8 to CTAB was 4:5, and the mass ratio of the total mass of ZIFs and surfactant to ethanol was 1:35.

[0072] Step (3): Add the ethanol solution containing TEOS dropwise to the suspension of step (2), and stir magnetically in a 50°C water bath for 20 hours to obtain an emulsion. The volume ratio of TEOS to anhydrous ethanol is 1:4.5, and the amount of TEOS ethanol solution added is controlled so that the mass ratio of TEOS to ZIFs in the mixed solution is 4.7:1. The obtained emulsion is centrifuged and washed three times with a mixed solution of deionized water and ethanol in a volume ratio of 1:1 to obtain ZIF-8@SiO2, which is then placed in a forced air oven for drying. The centrifugation process parameters of step (3) are set to a centrifugal speed of 8000 rpm and a centrifugal time of 30 minutes; the forced air oven drying parameters are set to a temperature of 60°C and a drying time of 24 hours.

[0073] Step (4): Deionized water and anhydrous ethanol were used to prepare a 95 wt% ethanol solution. The ZIF-8@SiO2 obtained in step (3) and the pre-hydrolyzed KH570 silane coupling agent were slowly added to the ethanol solution and ultrasonically dispersed for 15 minutes. The solution was stirred in a 40°C constant temperature water bath for 24 hours, centrifuged, and washed three times with a mixed solution of deionized water and ethanol in a volume ratio of 1:1 to obtain KH570-ZIF-8@SiO2, which was then placed in a forced air oven for drying. The mass ratio of ZIF-8@SiO2 to the pre-hydrolyzed KH570 silane coupling agent was 25:1, and the total mass ratio of the two to the 95 wt% ethanol solution was 1:80. The centrifugal process parameters were set as a centrifugal speed of 8000 rpm and a centrifugal time of 25 minutes; the forced air oven drying parameters were set as a temperature of 65°C and a drying time of 20 hours.

[0074] Step (5): Add the bismaleimide and cyanate ester and the KH570-ZIF-8@SiO2 filler obtained in step (4) to a beaker containing N-N-dimethylformamide, ultrasonically disperse for 10 minutes, and stir until the solution becomes clear and transparent. The mass ratio of bismaleimide to cyanate ester is 1:3, the mass of KH570-ZIF-8@SiO2 accounts for 3% of the total mass of bismaleimide and cyanate ester, and the mass ratio of the total mass of bismaleimide, cyanate ester, and KH570-ZIF-8@SiO2 powder to N-N-dimethylformamide is 1:1.

[0075] Step (6): The beaker containing the transparent solution obtained in step (5) was stirred on a heated stirring platform at 125° C. for 25 min to evaporate the N-dimethylformamide solvent until the color of the solution changed from light to dark.

[0076] Step (7): The solution obtained after the heating and stirring prepolymerization in step (6) was placed in a vacuum oven to remove the N-dimethylformamide solvent and air bubbles, and then poured into a polytetrafluoroethylene mold. The parameters for the vacuum oven solvent removal were set at a temperature of 110°C, a vacuum of -0.085 MPa, and a solvent removal time of 2 hours.

[0077] Step (8): Pour the prepolymer solution obtained in step (7) into a polytetrafluoroethylene mold, transfer the mold containing the prepolymer to a blast oven for staged heating and heat preservation curing treatment, that is, curing at 160°C for 2h, 180°C for 2h, 200°C for 2h, 220°C for 2h, and 230°C for 4h in sequence to obtain bismaleimide triazine resin, and the prepared composite material is a thin film material with a thickness of 700μm.

[0078] Comparative Example:

[0079] Compared with Examples 1-3, in this comparative example, the nano ZIFs@SiO2 powder modified by grafting with a silane coupling agent is not added as a modified filler; the other operating steps are basically the same, as follows:

[0080] Step (1): Add bismaleimide and cyanate to a beaker containing acetone, ultrasonically disperse for 12 minutes, and stir until the solution becomes clear and transparent. The mass ratio of bismaleimide to cyanate is 1:3, and the mass ratio of the total mass of bismaleimide and cyanate to acetone is 1:1.

[0081] Step (2): The beaker containing the transparent solution obtained in step (1) was stirred on a heated stirring platform at 115° C. for 35 min to evaporate the solvent until the color of the solution changed from light to dark.

[0082] Step (3): The solution obtained after the heating and stirring prepolymerization in step (2) was placed in a vacuum oven to remove the acetone solvent and air bubbles, and then poured into a polytetrafluoroethylene mold. The parameters for the vacuum oven solvent removal were set at a temperature of 80°C, a vacuum degree of -0.085 MPa, and a solvent removal time of 2 hours.

[0083] Step (4): pouring the prepolymer solution obtained in step (3) into a polytetrafluoroethylene mold, transferring the mold containing the prepolymer to a blast oven for staged heating and heat preservation curing treatment, that is, curing at 160°C for 2h, 180°C for 2h, 200°C for 2h, 220°C for 2h, and 230°C for 4h in sequence to obtain bismaleimide triazine resin, and the prepared composite material is a thin film material with a thickness of 500μm.

[0084] 3. Experimental data and results analysis:

[0085] The thin film materials prepared in the above-mentioned embodiments and comparative examples were characterized by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), dynamic mechanical analysis (DMA), and vector network analyzer for corresponding properties. The specific numerical test results are shown in Tables 1 and 2, respectively.

[0086] Table 1. Thermal properties of the products of the comparative examples and examples and the prepolymers

[0087] sample Comparative Example Example 1 Example 2 Example 3 5wt% thermal decomposition temperature (℃) 393.83 414.47 412.14 404.74 Maximum decomposition temperature (℃) 422.47 423.34 423.43 421.65 Glass transition temperature (℃) 292.58 288.80 284.69 280.90 Initial curing temperature (℃) 267.83 194.29 175.20 164.91 Curing peak temperature (℃) 302.04 216.71 208.44 200.01 Curing end temperature (℃) 323.56 237.01 230.87 221.94

[0088] Table 2. Dielectric properties of the products of comparative examples and examples

[0089] sample Comparative Example Example 1 Example 2 Example 3 Dielectric constant (10GHz) 3.11 2.93 2.82 2.73 Dielectric loss (10GHz) 0.014 0.011 0.0086 0.010

[0090] The present invention only needs to add 1% to 3% of the modified ZIFs@SiO2 nanomaterial as a filler to the resin matrix to significantly improve the performance of the matrix resin, thereby not only improving the dielectric properties of the composite material but also maintaining high thermal stability and thermal processability.

[0091] according to Figure 2 As shown in Table 1, the addition of silane coupling agent to modify the nano ZIFs@SiO2 filler can slow down the crystallization process of the resin and prolong the viscous flow processing time of the bismaleimide triazine resin, thereby improving the curing process of the resin. Figure 3 From the DSC curve, it can be seen that the addition of silane coupling agent modified nano ZIFs@SiO2 filler can significantly reduce the initial curing temperature, curing peak temperature and curing end temperature of bismaleimide triazine resin. When the mass addition amount of silane coupling agent modified nano ZIFs@SiO2 filler is 3%, the initial curing temperature of the composite material is reduced from 267.83℃ to 164.91℃, the curing peak temperature is reduced from 302.04℃ to 200.01℃, and the curing end temperature is reduced from 323.56℃ to 221.94℃, showing the catalytic effect of ZIFs ions on the resin. Figure 4 As shown in the cross-sectional SEM images, with the addition of fillers, the dispersion catalysis of the fillers plays a pinning and stabilizing role on the surrounding resin segments.

[0092] According to the data in Table 1 and Figure 5 It can be seen from the thermal weight loss curve that the addition of silane coupling agent to modify the nano ZIFs@SiO2 filler can improve the thermal stability of bismaleimide triazine resin. When the mass addition amount of silane coupling agent modified nano ZIFs@SiO2 filler is 1%, the thermal decomposition temperature of the composite material 5wt% changes from 393.83℃ to 414.47℃. Figure 6 From the change of the tanδ peak value in the DMA test curve, it can be seen that the addition of fillers has little effect on the glass transition temperature of the bismaleimide triazine resin, but it greatly improves the processing technology, thereby significantly reducing the curing processing cost of the base resin.

[0093] According to Table 2 and Figure 7 As can be seen from the dielectric constant and dielectric loss graph, the dielectric constant and dielectric loss of the bismaleimide triazine resin composite material containing silane coupling agent modified nano ZIFs@SiO2 of the present invention are lower than those of pure bismaleimide triazine resin. This is because the low dielectric constant of the ZIFs material itself and the catalytic formation of triazine rings increase the density of the resin and reduce the dielectric loss. Figure 1The TEM images of ZIFs and ZIFs@SiO2 shown in the figure show that ZIFs have high chemical activity. SiO2 coating of ZIFs can reduce the unevenness of resin catalytic curing, reduce the impact of the processing environment on ZIFs materials, and reduce the adverse effects of interface effects on dielectric properties.

[0094] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a bismaleimide triazine resin composite material containing a modified filler, characterized in that: Including steps: (1) Dissolving a transition metal nitrate hydrate and an imidazole ligand in deionized water, and performing a self-assembly reaction under ultrasonic dispersion and stirring conditions; and obtaining a porous nanomaterial ZIFs with a three-dimensional structure after centrifugal washing and drying. (2) adding porous nanomaterials ZIFs and surfactants into ethanol, adjusting the pH to alkaline, and obtaining a suspension by ultrasonic dispersion; An ethanol solution of ethyl silicate (TEOS) was added dropwise to the suspension and stirred continuously under heating conditions to obtain an emulsion. The solid product after centrifugation was washed and dried to obtain a porous nanomaterial ZIFs@SiO2 coated with a SiO2 shell. (3) pre-hydrolyzing the silane coupling agent, and then adding it together with the porous nanomaterial ZIFs@SiO2 into an ethanol solution, and continuously stirring under heating conditions after ultrasonic dispersion to obtain a suspension; centrifuging and drying to obtain a nano ZIFs@SiO2 powder grafted with the silane coupling agent; (4) adding the bismaleimide resin and cyanate resin as the matrix into an organic solvent and stirring until clear and transparent; then adding the modified nano ZIFs@SiO2 powder as filler and ultrasonically dispersing it uniformly to obtain a transparent solution; (5) The transparent solution is continuously stirred under heating conditions for prepolymerization, and the color of the solution changes from light to dark; then it is moved to a vacuum oven, and the organic solvent and bubbles are removed under vacuum and heating conditions. After taking it out, it is poured into a mold and subjected to a staged heating and heat preservation curing treatment. After demolding, a bismaleimide triazine resin composite material containing modified ZIFs@SiO2 nanofiller is obtained.

2. The method according to claim 1, characterized in that In the step (1), at room temperature, ultrasonic dispersion is first performed for 5 to 10 minutes, and then magnetic stirring is performed for 20 to 30 minutes to complete the self-assembly reaction.

3. The method according to claim 1, characterized in that In the step (1), the transition metal nitrate hydrate is zinc nitrate hexahydrate, and the imidazole ligand is 2-methylimidazole; the molar ratio of the transition metal nitrate hydrate, the imidazole ligand and deionized water is 1:70-75:1400-1500.

4. The method according to claim 1, wherein In the step (2), the surfactant is hexadecyltrimethylammonium bromide; the mass ratio of the porous nanomaterial ZIFs to the surfactant is 4:5; the mass ratio of the total mass of the ZIFs and the surfactant to ethanol is 1:30-40; in the TEOS ethanol solution, the volume ratio of TEOS to ethanol is 1:4-5; and the amount of the TEOS ethanol solution added is controlled so that the mass ratio of TEOS to ZIFs in the mixed solution is 4.5-5:

1.

5. The method according to claim 1, wherein In the step (2), ammonia water is used to adjust the pH value to between 11 and 11.6; ultrasonic dispersion is performed for 10 to 15 minutes to obtain a suspension; and magnetic stirring is performed at 50° C. for 18 to 24 hours to obtain an emulsion.

6. The method according to claim 1, characterized in that In the step (3), the silane coupling agent is γ-methacryloxypropyltrimethoxysilane (KH570); the mass fraction of the ethanol solution is 95wt%, and it is prepared with deionized water and anhydrous ethanol; the mass ratio of the pre-hydrolyzed silane coupling agent to ZIFs@SiO2 is 1:20-25, and the mass ratio of the total mass of the two to the 95wt% ethanol solution is 1:80-100.

7. The method according to claim 1, characterized in that In the step (3), after ultrasonic dispersion for 10 to 20 minutes, the mixed solution is transferred to a constant temperature water bath at 40 to 55° C. and stirred for 16 to 24 hours to obtain a suspension.

8. The method according to claim 1, characterized in that In the step (4), the bismaleimide resin is 4,4'-diaminodiphenylmethane bismaleimide, and the cyanate resin is bisphenol A cyanate; the organic solvent is any one of acetone, 2-butanone or N-N dimethylformamide; the mass ratio of the bismaleimide resin to the cyanate resin is 1:3, the filler powder accounts for 1% to 3% of the total mass of the resin matrix, and the ratio of the total mass of the three to the mass of the organic solvent is 1:

1.

9. The method according to claim 1, characterized in that In the step (4), the ultrasonic dispersion time is 10 to 15 minutes.

10. The method according to claim 1, characterized in that In the step (5), during the prepolymerization of the transparent solution, the heating temperature is 115-125°C, and the stirring is continued for 25-35 minutes; in the vacuum oven, the vacuum degree is -0.085MPa, the temperature is 80-110°C, and the drying time is 2 hours; the mold is made of polytetrafluoroethylene; the staged heating and heat preservation curing treatment is carried out in a blast oven, and the curing is carried out at 160°C for 2 hours, 180°C for 2 hours, 200°C for 2 hours, 220°C for 2 hours, and 230°C for 4 hours in sequence; the obtained composite material is a thin film material with a thickness between 650 and 800 μm.

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