Polyarylene ether nitrile dielectric film and preparation method thereof

Abstract

The present invention relates to a polyarylethernitrile dielectric film and a preparation method thereof, and belongs to the technical field of polymer dielectric materials. The technical problem solved by the present invention is to provide a preparation method of a polyarylethernitrile dielectric film with a simple process. The method first prepares a polyarylethernitrile microporous film; then immerses it in a nano-barium titanate sol, dries it, and stacks and hot presses it to obtain a polyarylethernitrile dielectric film. The present invention obtains a hydrophilic sulfonated polyarylethernitrile film with a microporous structure by direct coating, acid washing, and purification, thereby improving the compatibility with the sol, facilitating the sol to enter the matrix material for compounding, and adopts a sol-gel method to synthesize the barium titanate sol and repeatedly immerse and treat the film to successfully prepare a polyarylethernitrile dielectric film. The filler has good dispersion in the matrix resin, maintaining good thermal and mechanical properties, with a tensile strength greater than 94MPa and a heat deformation temperature greater than 140°C. The method is simple to operate and easy to control, can be mass-produced, and has important application value in the field of high dielectric film materials.

Description

Technical Field

[0001] The invention relates to a polyarylethernitrile dielectric film and a preparation method thereof, belonging to the technical field of polymer dielectric materials. Background Art

[0002] Poly(arylene ether nitrile) is a new class of specialty polymer materials that exhibits high-temperature cyclic resistance, good self-lubrication, excellent mechanical properties, flame retardancy, radiation resistance, insulation, and chemical stability. The presence of polar cyano side groups imparts a high dielectric constant to poly(arylene ether nitrile), with pure polymers reaching values as high as 3.8 to 6.0. This has broad practical value for the development of high-performance dielectric polymers.

[0003] Traditionally, poly(arylene ether nitrile) thin films are prepared using a solution casting method. This involves pulverizing the synthesized poly(arylene ether nitrile) solution, purifying it, and drying it, then redissolving it in a non-polar solvent. The resulting poly(arylene ether nitrile) thin film is then cast into a film. Finally, the solvent is removed at high temperature to obtain the poly(arylene ether nitrile) thin film. This process is cumbersome, and the resulting film surface is relatively smooth, hindering the subsequent compounding of the film material with fillers in the preparation of high-dielectric composites. Furthermore, problems such as uneven dispersion and poor compatibility are unavoidable.

[0004] The preparation of high dielectric composite materials is to directly incorporate solid fillers, which has the problem of poor dispersion of fillers in the matrix resin. The resulting dielectric material has a low dielectric constant and high dielectric loss, which needs to be improved.

[0005] Patent CN112778744A uses dopamine hydrochloride to modify barium titanate particles, which are then mixed with a poly(arylene ether nitrile) solution to create a suspension that is then cast into a film. Patent CN112210203A first prepares polyaniline-coated barium titanate nanowires (PANI@BT NWs), then drips the PANI@BT NWs dispersion into a poly(arylene ether nitrile) solution, disperses them, and then naturally casts them into a film.

[0006] In summary, the existing technology is to improve the filler, the method is relatively complex and costly, and the comprehensive performance of the resulting dielectric coating also needs to be further improved. Summary of the Invention

[0007] In view of the above defects, the technical problem solved by the present invention is to provide a method for preparing a poly(arylene ether nitrile) dielectric film with a simple process.

[0008] The method for preparing the polyarylethernitrile dielectric film of the present invention comprises the following steps:

[0009] a. Preparation of poly(arylene ether nitrile) microporous film: uniformly coating a sulfonated poly(arylene ether nitrile) solution on a flat plate, then soaking it in dilute acid, washing it with water, and drying it to obtain a poly(arylene ether nitrile) microporous film;

[0010] b. Impregnation: impregnating the poly(arylene ether nitrile) microporous film in a nano-barium titanate sol and drying the film to obtain an impregnated poly(arylene ether nitrile) film;

[0011] c. Lamination and hot pressing: The polyarylethernitrile films are laminated and hot pressed to obtain a polyarylethernitrile dielectric film.

[0012] In one embodiment of the present invention, the structure of the sulfonated poly (arylene ether nitrile) is:

[0013]

[0014] Wherein, 0.2≤m / (n+m)≤0.4, M is potassium or sodium; and the number average molecular weight of the sulfonated poly(arylene ether nitrile) is 30,000 to 40,000.

[0015] In one embodiment, the solid-liquid weight ratio of the sulfonated poly(arylene ether nitrile) solution is 0.6 to 0.8.

[0016] In a specific embodiment, the sulfonated poly (arylene ether nitrile) solution is synthesized by the following method:

[0017] S1: adding equimolar amounts of a dihydric phenol and a 2,6-difluorobenzonitrile monomer into an NMP solvent to dissolve the dihydric phenol; the dihydric phenol is bisphenol A and 2,5-dihydroxybenzenesulfonate, and the 2,5-dihydroxybenzenesulfonate accounts for 20% to 40% of the molar amount of the dihydric phenol;

[0018] S2: Add toluene and excess potassium carbonate and reflux at 170-180°C for dehydration;

[0019] S3: heating the system to 200-210°C for polymerization reaction;

[0020] S4: After the reaction is completed, the temperature is lowered and a solvent is added to dilute the solution to obtain a sulfonated poly (arylene ether nitrile) solution.

[0021] Preferably, in step a, the dilute acid is dilute hydrochloric acid with a mass concentration of 10 to 30%, and the soaking time is 1 hour.

[0022] In one embodiment of the present invention, in step b, the drying temperature is 160-180°C.

[0023] In one embodiment of the present invention, step b is repeated 5 to 10 times.

[0024] In one embodiment of the present invention, the nano-barium titanate sol is synthesized by a sol-gel method.

[0025] Preferably, any one of the following methods is used to prepare the nano-barium titanate sol:

[0026] Method 1: dissolving barium hydroxide in ethylene glycol methyl ether to prepare a barium hydroxide solution; dissolving butyl titanate in methanol to prepare a butyl titanate solution; fully mixing the barium hydroxide solution and the butyl titanate solution to dissolve each other, and adding water to form a sol;

[0027] Method 2: Dissolve butyl titanate in isopropyl alcohol, add glacial acetic acid and stir to dissolve; then add barium acetate acetic acid solution; finally, adjust the pH to 3-4 with glacial acetic acid and stir in a water bath at 80°C to form a sol;

[0028] Method 3: dissolving barium acetate in acetic acid to prepare a barium acetate solution; dissolving butyl titanate in anhydrous ethanol to prepare a butyl titanate solution; mixing the barium acetate solution and the butyl titanate solution to form a sol.

[0029] In one embodiment of the present invention, in step c, the hot pressing temperature is 300-340° C. and the pressure is 10-15 MPa.

[0030] The present invention also provides a polyarylene ether nitrile dielectric film prepared by the method for preparing the polyarylene ether nitrile dielectric film of the present invention.

[0031] The polyarylethernitrile dielectric film of the present invention has good mechanical properties and better dielectric properties, with a tensile strength greater than 94 MPa, a heat deformation temperature greater than 140° C., a dielectric constant greater than 8, and a dielectric loss less than 0.02.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention obtains a hydrophilic sulfonated poly(arylene ether nitrile) film with a microporous structure by direct coating, acid washing and purification, thereby improving the compatibility with the sol and facilitating the sol to enter the matrix material for compounding.

[0034] 2. The present invention adopts a sol-gel method to synthesize barium titanate sol and repeatedly immerses the film to successfully prepare a poly(arylene ether nitrile) dielectric film (ε=8.6; tanδ=0.019).

[0035] 3. The filler of the present invention has good dispersibility in the matrix resin and maintains good thermal and mechanical properties, with a tensile strength of >94 MPa and a heat deformation temperature of >140°C.

[0036] 4. The method of the present invention is simple to operate and easy to control, can be mass-produced, and has important application value in the field of high dielectric thin film materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a cross-sectional SEM image of the poly(arylene ether nitrile) dielectric film prepared in Example 1 of the present invention.

[0038] Figure 2This is a cross-sectional SEM image of the poly(arylene ether nitrile) dielectric film prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The method for preparing the polyarylethernitrile dielectric film of the present invention comprises the following steps:

[0040] a. Preparation of poly(arylene ether nitrile) microporous film: uniformly coating a sulfonated poly(arylene ether nitrile) solution on a flat plate, then soaking it in dilute acid, washing it with water, and drying it to obtain a poly(arylene ether nitrile) microporous film;

[0041] b. Impregnation: impregnating the poly(arylene ether nitrile) microporous film in a nano-barium titanate sol and drying the film to obtain an impregnated poly(arylene ether nitrile) film;

[0042] c. Lamination and hot pressing: The polyarylethernitrile films are laminated and hot pressed to obtain a polyarylethernitrile dielectric film.

[0043] The method of the present invention uses a sulfonated poly(arylene ether nitrile) solution as raw material. A hydrophilic sulfonated poly(arylene ether nitrile) film with a microporous structure is obtained by direct coating, acid washing, and purification. This improves compatibility with the sol, facilitating the sol's incorporation into a matrix material for composite reuse. A barium titanate sol is synthesized using a sol-gel method and the film is repeatedly impregnated. The resulting poly(arylene ether nitrile) dielectric film with a high dielectric constant and low dielectric loss is prepared by hot pressing. The filler has good dispersion in the matrix resin, resulting in a dielectric film exhibiting excellent overall performance.

[0044] In one embodiment of the present invention, the structure of the sulfonated poly (arylene ether nitrile) is:

[0045]

[0046] Wherein, 0.2≤m / (n+m)≤0.4, M is potassium or sodium; and the number average molecular weight of the sulfonated poly(arylene ether nitrile) is 30,000 to 40,000.

[0047] Unless otherwise specified, the molecular weight in the present invention is the number average molecular weight.

[0048] In one embodiment, the solid-liquid weight ratio of the sulfonated poly(arylene ether nitrile) solution is 0.6 to 0.8; preferably, the solid-liquid weight ratio of the sulfonated poly(arylene ether nitrile) solution is 0.7.

[0049] In a specific embodiment, the sulfonated poly (arylene ether nitrile) solution is synthesized by the following method:

[0050] S1: adding equimolar amounts of a dihydric phenol and a 2,6-difluorobenzonitrile monomer to an NMP solvent for dissolution; the dihydric phenol is bisphenol A and 2,5-dihydroxybenzenesulfonate, and the 2,5-dihydroxybenzenesulfonate accounts for 20% to 40% of the molar amount of the dihydric phenol; preferably, the 2,5-dihydroxybenzenesulfonate is potassium 2,5-dihydroxybenzenesulfonate or sodium 2,5-dihydroxybenzenesulfonate;

[0051] S2: Add toluene and excess potassium carbonate and reflux at 170-180°C for dehydration;

[0052] S3: heating the system to 200-210°C for polymerization reaction;

[0053] S4: After the reaction is completed, the temperature is lowered and a solvent is added to dilute the solution to obtain a sulfonated poly (arylene ether nitrile) solution.

[0054] Preferably, in step a, the dilute acid is dilute hydrochloric acid with a mass concentration of 10 to 30%, and the soaking time is 1 hour.

[0055] In one embodiment of the present invention, in step b, the drying temperature is 160-180°C.

[0056] In one embodiment of the present invention, step b is repeated 5 to 10 times.

[0057] In one embodiment of the present invention, the nano-barium titanate sol is synthesized by a sol-gel method.

[0058] The sol-gel method can prepare a homogeneous sol state of nanofillers. It uses compounds containing highly chemically active components as precursors, uniformly mixes these raw materials in the liquid phase, and undergoes hydrolysis and condensation chemical reactions to form a stable transparent sol system in the solution, which further forms a gel. Finally, after drying and sintering and solidification, molecular and even nano-substructured materials can be prepared.

[0059] Preferably, any one of the following methods is used to prepare the nano-barium titanate sol:

[0060] Method 1: dissolving barium hydroxide in ethylene glycol methyl ether to prepare a barium hydroxide solution; dissolving butyl titanate in methanol to prepare a butyl titanate solution; fully mixing the barium hydroxide solution and the butyl titanate solution to dissolve each other, and adding water to form a sol;

[0061] Method 2: Dissolve butyl titanate in isopropyl alcohol, add glacial acetic acid and stir to dissolve; then add barium acetate acetic acid solution; finally, adjust the pH to 3-4 with glacial acetic acid and stir in a water bath at 80°C to form a sol;

[0062] Method 3: dissolving barium acetate in acetic acid to prepare a barium acetate solution; dissolving butyl titanate in anhydrous ethanol to prepare a butyl titanate solution; mixing the barium acetate solution and the butyl titanate solution to form a sol.

[0063] In one embodiment of the present invention, in step c, the hot pressing temperature is 300-340° C. and the pressure is 10-15 MPa.

[0064] The polyarylethernitrile dielectric film of the present invention has good mechanical properties and better dielectric properties, with a tensile strength greater than 94 MPa, a heat deformation temperature greater than 140° C., a dielectric constant greater than 8, and a dielectric loss less than 0.02.

[0065] The specific embodiments of the present invention are further described below in conjunction with examples, but the present invention is not limited to the scope of the examples.

[0066] Example 1

[0067] The present embodiment provides a poly(arylene ether nitrile) dielectric film and a preparation method thereof. First, a synthesized sulfonated poly(arylene ether nitrile) solution is uniformly coated on a glass plate. Then, the poly(arylene ether nitrile) microporous film is obtained after dilute acid elution, water washing, purification, and drying. Next, nano-barium titanate is synthesized by a sol-gel method. The film is repeatedly immersed in a barium titanate sol and dried. Finally, the poly(arylene ether nitrile) films are stacked and hot-pressed to prepare a poly(arylene ether nitrile) dielectric film.

[0068] The specific steps include:

[0069] Step 1: Dissolve an equal amount of dihydric phenol and 2,6-difluorobenzonitrile monomer in NMP solvent. Add toluene and excess potassium carbonate and reflux at 180°C for dehydration. Heat the system to 205°C for polymerization. After the reaction, cool the system and add solvent to dilute the system to a solid-to-liquid weight ratio of 0.7, thereby obtaining a sulfonated poly(arylene ether nitrile) solution. The dihydric phenol is bisphenol A and potassium 2,5-dihydroxybenzenesulfonate, with the potassium 2,5-dihydroxybenzenesulfonate comprising 40% of the molar weight of the dihydric phenol.

[0070] Step 2: Pour the sulfonated poly(arylene ether nitrile) solution onto a glass plate and evenly spread it to form a film; then immediately place it in 10% dilute hydrochloric acid and soak it for 1 hour; then take out the film and wash and purify it in boiling water 4 times; finally, place the film at 120°C and dry it for 6 hours to obtain a poly(arylene ether nitrile) microporous film.

[0071] Step 3: Prepare barium titanate sol: first dissolve barium hydroxide in ethylene glycol methyl ether to prepare a solution; then dissolve butyl titanate in methanol to prepare a solution; finally, fully mix the two solutions to dissolve each other, and add a small amount of water to form a sol.

[0072] Step 4: Immerse the poly(arylene ether nitrile) film in the barium titanate sol, take it out after a period of time, dry it at 160° C. for 2 hours, and repeat the process 6 times.

[0073] Step 5: stack six poly(arylene ether nitrile) films and perform hot pressing in a mold at a temperature of 320° C. and a pressure of 15 MPa to prepare a poly(arylene ether nitrile) dielectric film.

[0074] Example 2

[0075] The present embodiment provides a poly(arylene ether nitrile) dielectric film and a preparation method thereof. First, a synthesized sulfonated poly(arylene ether nitrile) solution is uniformly coated on a glass plate. Then, the poly(arylene ether nitrile) microporous film is obtained after dilute acid elution, water washing, purification, and drying. Next, nano-barium titanate is synthesized by a sol-gel method. The film is repeatedly immersed in a barium titanate sol and dried. Finally, the poly(arylene ether nitrile) films are stacked and hot-pressed to prepare a poly(arylene ether nitrile) dielectric film.

[0076] The specific steps include:

[0077] Step 1: Dissolve an equal amount of dihydric phenol and 2,6-difluorobenzonitrile monomer in NMP solvent. Add toluene and excess potassium carbonate and reflux at 170°C for dehydration. Heat the system to 205°C for polymerization. After the reaction, cool the system and add solvent to dilute the system to a solid-to-liquid weight ratio of 0.6, thereby obtaining a sulfonated poly(arylene ether nitrile) solution. The dihydric phenol is bisphenol A and potassium 2,5-dihydroxybenzenesulfonate, with the potassium 2,5-dihydroxybenzenesulfonate comprising 30% of the molar weight of the dihydric phenol.

[0078] Step 2: Pour the sulfonated poly(arylene ether nitrile) solution onto a glass plate and evenly spread it to form a film; then immediately place it in 20% dilute hydrochloric acid and soak it for 1 hour; then take out the film and wash and purify it in boiling water 5 times; finally, place the film at 140°C and dry it for 4 hours to obtain a poly(arylene ether nitrile) microporous film.

[0079] Step 3: Prepare barium titanate sol: first dissolve butyl titanate in isopropyl alcohol, add glacial acetic acid and stir to dissolve; then add acetic acid to dissolve the mixed solution of barium acetate; finally, adjust the pH of the mixed solution to 3-4 with glacial acetic acid, and stir the sol in an 80°C water bath.

[0080] Step 4: Immerse the poly(arylene ether nitrile) film in the barium titanate sol, take it out after a period of time, dry it at 160° C. for 3 hours, and repeat the process 6 times.

[0081] Step 5: stack 8 polyarylethernitrile films and perform hot pressing in a mold at a temperature of 330° C. and a pressure of 10 MPa to prepare a polyarylethernitrile dielectric film.

[0082] Example 3

[0083] This embodiment provides a poly(arylene ether nitrile) dielectric film and its preparation method. First, a synthesized sulfonated poly(arylene ether nitrile) solution is uniformly coated on a glass plate. Then, after dilute acid elution, water washing, purification, and drying, a poly(arylene ether nitrile) microporous film is obtained. Next, nano-barium titanate is synthesized by a sol-gel method. The film is repeatedly immersed in a barium titanate sol and dried. Finally, the poly(arylene ether nitrile) films are stacked and hot-pressed to prepare a poly(arylene ether nitrile) dielectric film. The dihydric phenol is bisphenol A and potassium 2,5-dihydroxybenzenesulfonate, and the potassium 2,5-dihydroxybenzenesulfonate accounts for 20% of the molar amount of the dihydric phenol.

[0084] The specific steps include:

[0085] Step 1: Add equal moles of dihydric phenol and 2,6-difluorobenzonitrile monomer into NMP solvent to dissolve, add toluene and excess potassium carbonate to reflux and dehydrate at 180°C, heat the system to 210°C for polymerization reaction, cool after the reaction and add solvent to dilute the system to a solid-liquid weight ratio of 0.8 to obtain a sulfonated polyarylene ether nitrile solution.

[0086] Step 2: Pour the sulfonated poly(arylene ether nitrile) solution onto a glass plate and evenly spread it to form a film; then immediately place it in 10% dilute hydrochloric acid and soak it for 1 hour; then take out the film and wash and purify it in boiling water 4 times; finally, place the film at 130°C and dry it for 5 hours to obtain a poly(arylene ether nitrile) microporous film.

[0087] Step 3: Prepare barium titanate sol: first dissolve barium acetate in acetic acid to prepare a solution; then dissolve butyl titanate in anhydrous ethanol to prepare a solution; finally, quickly mix the two solutions and stir for 2 hours to form a transparent sol.

[0088] Step 4: Immerse the poly(arylene ether nitrile) film in the barium titanate sol, take it out after a period of time, dry it at 160° C. for 2 hours, and repeat the process 6 times.

[0089] Step 5: stack four poly(arylene ether nitrile) films, and perform hot pressing in a mold at a temperature of 330° C. and a pressure of 15 MPa to prepare a poly(arylene ether nitrile) dielectric film.

[0090] Comparative Example 1

[0091] This comparative example provides a polyarylethernitrile dielectric film and a preparation method thereof. First, a sulfonated polyarylethernitrile resin is synthesized; then, the sulfonated polyarylethernitrile is dissolved in a solvent, and a nano-barium titanate filler is added and evenly dispersed; then, a film is formed by a casting method, and the solvent is removed at a high temperature to obtain a polyarylethernitrile film; finally, the polyarylethernitrile films are stacked and hot-pressed to prepare a polyarylethernitrile dielectric film.

[0092] The specific steps include:

[0093] Step 1: Dissolve an equal amount of dihydric phenol and 2,6-difluorobenzonitrile monomer in NMP solvent. Add toluene and excess potassium carbonate, reflux at 180°C for dehydration, heat the system to 205°C for polymerization, and finally grind, purify, and dry to obtain a sulfonated polyarylethernitrile resin. The dihydric phenol is bisphenol A and potassium 2,5-dihydroxybenzenesulfonate, with the potassium 2,5-dihydroxybenzenesulfonate comprising 40% of the molar weight of the dihydric phenol.

[0094] Step 2: dissolving the sulfonated poly(arylene ether nitrile) in DMF solvent, adding 20 wt % of nano-barium titanate filler and dispersing the mixture evenly to obtain a mixed solution.

[0095] Step 3: The mixed solution is formed into a film by a casting method, and maintained at 180° C. for 6 hours to remove the solvent to obtain a polyarylene ether nitrile film.

[0096] Step 4: stack six poly(arylene ether nitrile) films and perform hot pressing in a mold at a temperature of 320° C. and a pressure of 15 MPa to prepare a poly(arylene ether nitrile) dielectric film.

[0097] Comparative Example 2

[0098] This comparative example provides a poly(arylene ether nitrile) dielectric film and a preparation method thereof. First, a synthesized bisphenol A poly(arylene ether nitrile) solution is uniformly coated on a glass plate; then, the poly(arylene ether nitrile) microporous film is obtained after elution with dilute acid, purification by water washing, and drying; secondly, nano-barium titanate is synthesized by a sol-gel method, and the film is repeatedly immersed in a barium titanate sol and dried; finally, the poly(arylene ether nitrile) films are stacked and hot-pressed to prepare a poly(arylene ether nitrile) dielectric film.

[0099] The specific steps include:

[0100] Step 1: Equimolar amounts of bisphenol A and 2,6-dichlorobenzonitrile monomers are added to NMP solvent for dissolution, toluene and excess potassium carbonate are added, and the mixture is refluxed and dehydrated at 180°C. The system is heated to 205°C for polymerization. After the reaction is completed, the temperature is lowered and solvent is added to dilute the system to a solid-liquid ratio of 0.7, thereby obtaining a bisphenol A type polyarylether nitrile solution.

[0101] Step 2: Pour the bisphenol A poly(arylene ether nitrile) solution onto a glass plate and evenly spread it to form a film; then immediately place it in 10% dilute hydrochloric acid and soak it for 1 hour; then take out the film and wash and purify it in boiling water 4 times; finally, place the film at 120°C and dry it for 6 hours to obtain a poly(arylene ether nitrile) microporous film.

[0102] Step 3: Prepare barium titanate sol: first dissolve barium hydroxide in ethylene glycol methyl ether to prepare a solution; then dissolve butyl titanate in methanol to prepare a solution; finally, fully mix the two solutions to dissolve each other, and add a small amount of water to form a sol.

[0103] Step 4: Immerse the poly(arylene ether nitrile) film in the barium titanate sol, take it out after a period of time, dry it at 160° C. for 2 hours, and repeat the process 6 times.

[0104] Step 5: stack six poly(arylene ether nitrile) films and perform hot pressing in a mold at a temperature of 320° C. and a pressure of 15 MPa to prepare a poly(arylene ether nitrile) dielectric film.

[0105] The mechanical, thermal, and dielectric properties of the poly(arylene ether nitrile) dielectric films of the examples and comparative examples were tested. The test results are shown in Table 1 below.

[0106] Table 1

[0107]

[0108] From the performance test results in the above table, it can be seen that the embodiment directly coated, pickled, and purified to obtain a sulfonated poly(arylene ether nitrile) film with a microporous structure, and the sol-gel method was used to synthesize barium titanate sol and repeatedly immerse the film to successfully prepare a poly(arylene ether nitrile) dielectric film with a dielectric constant greater than 8 and a dielectric loss less than 0.02; at the same time, the composite film has good compatibility and dispersibility, and a dielectric film with the best overall performance was obtained. Compared with Comparative Example 1, the composite film was prepared using a traditional method. Although good dielectric properties were also obtained, the mechanical properties were sacrificed due to poor compatibility and dispersibility. In Comparative Example 2, bisphenol A poly(arylene ether nitrile) was used to prepare the dielectric film. Compared with the sulfonated poly(arylene ether nitrile), the sulfonated poly(arylene ether nitrile) had better compatibility with the barium titanate sol, resulting in a higher dielectric constant.

Claims

1. A method for preparing a poly(arylene ether nitrile) dielectric film, characterized in that: The following steps are involved: a. Preparation of poly(arylene ether nitrile) microporous film: uniformly coating a sulfonated poly(arylene ether nitrile) solution on a flat plate, then soaking it in dilute acid, washing it with water, and drying it to obtain a poly(arylene ether nitrile) microporous film; b. Impregnation: impregnating the poly(arylene ether nitrile) microporous film in a nano-barium titanate sol and drying the film to obtain an impregnated poly(arylene ether nitrile) film; c. Lamination and hot pressing: lamination and hot pressing of the poly(arylene ether nitrile) films to obtain a poly(arylene ether nitrile) dielectric film; The structure of sulfonated poly (arylene ether nitrile) is: Wherein, 0.2≤m / (n+m)≤0.4, M is potassium or sodium; and the number average molecular weight of the sulfonated poly(arylene ether nitrile) is 30,000 to 40,000.

2. The method for preparing a poly(arylene ether nitrile) dielectric film according to claim 1, wherein: The solid-liquid weight ratio of the sulfonated polyarylethernitrile solution is 0.6-0.

8.

3. The method for preparing a poly(arylene ether nitrile) dielectric film according to claim 1, wherein: Sulfonated poly (arylene ether nitrile) solution was synthesized by the following method: S1: adding equimolar amounts of a dihydric phenol and a 2,6-difluorobenzonitrile monomer into an NMP solvent to dissolve the dihydric phenol; the dihydric phenol is bisphenol A and 2,5-dihydroxybenzenesulfonate, and the 2,5-dihydroxybenzenesulfonate accounts for 20% to 40% of the molar amount of the dihydric phenol; S2: Add toluene and excess potassium carbonate and reflux at 170-180°C for dehydration; S3: heating the system to 200-210°C for polymerization reaction; S4: After the reaction is completed, the temperature is lowered and a solvent is added to dilute the solution to obtain a sulfonated poly (arylene ether nitrile) solution.

4. The method for preparing a poly(arylene ether nitrile) dielectric film according to claim 1, wherein: In step a, the dilute acid is dilute hydrochloric acid with a mass concentration of 10-30%, and the soaking time is 1 hour.

5. The method for preparing a poly(arylene ether nitrile) dielectric film according to claim 1, wherein: In step b, the drying temperature is 160-180°C.

6. The method for preparing a poly(arylene ether nitrile) dielectric film according to claim 1, wherein: Repeat step b 5 to 10 times.

7. The method for preparing a poly(arylene ether nitrile) dielectric film according to claim 1, wherein: Nano-barium titanate sol is synthesized by sol-gel method; any one of the following methods is used: Method 1: dissolving barium hydroxide in ethylene glycol methyl ether to prepare a barium hydroxide solution; dissolving butyl titanate in methanol to prepare a butyl titanate solution; fully mixing the barium hydroxide solution and the butyl titanate solution to dissolve each other, and adding water to form a sol; Method 2: Dissolve butyl titanate in isopropyl alcohol, add glacial acetic acid and stir to dissolve; then add barium acetate acetic acid solution; finally, adjust the pH to 3-4 with glacial acetic acid and stir in a water bath at 80°C to form a sol; Method 3: dissolving barium acetate in acetic acid to prepare a barium acetate solution; dissolving butyl titanate in anhydrous ethanol to prepare a butyl titanate solution; mixing the barium acetate solution and the butyl titanate solution to form a sol.

8. The method for preparing a poly(arylene ether nitrile) dielectric film according to claim 1, wherein: In step c, the hot pressing temperature is 300-340° C. and the pressure is 10-15 MPa.

9. The polyarylene ether nitrile dielectric film prepared by the method for preparing the polyarylene ether nitrile dielectric film according to any one of claims 1 to 8.

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