Copolymerized polyamide having dielectric function containing nylon 1 segment and preparation method

Abstract

The present application belongs to the technical field of synthesis of all-organic polymer dielectric film, and particularly relates to a copolymerized polyamide with dielectric function containing nylon 1 chain segment and a preparation method, the preparation method of the dielectric polyamide film containing nylon 1 chain segment comprising the following steps: synthesis of nylon 1 with different polymerization degrees, butane diacid anhydride end-capping nylon 1, and salt formation of the end-capped product (referred to as "PA1 diacid") and piperazine, copolycondensation reaction of piperazine-PA1 diacid salt and piperazine-dodecanedioic acid salt, and hot-pressing forming, etc. In the present application, the piperazine-PA1 diacid salt and the piperazine-dodecanedioic acid salt are copolycondensed through high temperature and high pressure, the high dielectric constant of the nylon 1 chain segment is combined with the unique low dielectric loss of the piperazine nylon, the nylon 1 is embedded into the piperazine nylon matrix as a dielectric function chain segment, and the dielectric polyamide film containing the nylon 1 chain segment is directly prepared through simple hot-pressing forming.

Description

Technical Field

[0001] This invention belongs to the field of synthesis technology of all-organic polymer dielectric films, specifically relating to a copolyamide containing nylon 1 segments with dielectric function and its preparation method. Background Technology

[0002] Polymer film capacitors are widely used in electric vehicles, pulse power systems, and smart grids due to their ease of processing and high voltage resistance. In recent decades, biaxially oriented polypropylene (BOPP) has become the most popular polymer dielectric due to its low dielectric loss (tanδ < 0.003) and high breakdown strength (> 500 MV / m). However, its low dielectric constant (1.8-2.2) results in low energy density, which severely hinders its application in advanced pulse electronic devices. Therefore, the application of next-generation polymer film capacitors urgently requires dielectric polymers with high dielectric constants.

[0003] Nylon 1, also known as PAI or polycarbonylurea, has the following chemical structure: It possesses the highest amide group density and hydrogen bond density among polyamides, theoretically making it the nylon material with the highest dielectric constant. With appropriate heat treatment, its maximum dielectric constant can reach 30-40@(10) 2 -10 5 However, due to its rigid polymer chains and strong intermolecular forces, nylon 1 is typically a rigid powder, making it difficult to process into films, which greatly limits its application as a dielectric functional material. The inventors previously attempted to directly add nylon 1 as a dielectric functional filler to PVDF and nylon 11 matrices, resulting in a significant improvement in the dielectric constant of the prepared composite dielectrics. However, the introduction of nylon 1 also created numerous phase interfaces, leading to high dielectric loss in the composite dielectrics and hindering practical applications.

[0004] Currently, no similar methods for solving the above problems have been reported in the literature. Through copolymerization, the excellent properties of each structural unit can be combined without leading to the complex phase interfaces found in composite materials. Therefore, introducing nylon 1 as a dielectric functional segment into the molecular chain of polymers with low dielectric loss and excellent mechanical properties holds promise for combining the high dielectric constant of nylon 1 with the low dielectric loss and excellent film-forming properties of other polymers.

[0005] This invention uses nylon piperazine-12, which has low dielectric loss and excellent mechanical properties, as the base polymer and nylon 1 as the functional structural unit. The process involves end-capping nylon 1, forming a salt with piperazine, and then copolymerizing it with piperazine-dodecanoate. A dielectric polyamide film containing nylon 1 segments is then obtained through simple hot pressing or extrusion molding. The overall properties of the resulting dielectric film can be easily adjusted by selecting nylon 1 with different degrees of polymerization and adjusting the molar content of the nylon 1 segments. The polyamide film prepared by this invention possesses high dielectric constant, low dielectric loss, and excellent mechanical toughness, and provides a new approach for the chemical structure design of dielectric polymers. Summary of the Invention

[0006] This invention provides a method for preparing dielectric polyamide films containing nylon 1 segments, addressing the problems of low dielectric constant in existing polymer dielectrics and the difficulty in thin-film fabrication of nylon 1 as previously reported. By introducing nylon 1 segments of different lengths or molar contents into the molecular chain of nylon piperazine-12, this invention combines the high dielectric constant of nylon 1 segments with the low dielectric loss and excellent mechanical properties of piperazine long-chain dicarboxylic acid nylon, greatly promoting the application of nylon 1 as a novel dielectric functional material in the field of thin-film capacitors, and providing a new approach and method for the chemical structure design of dielectric polymers.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a copolyamide containing nylon 1 segments and having dielectric function, the structural formula of which is:

[0008]

[0009] Where n = 3-8, the nylon 1 segment imparts a high dielectric constant to the polyamide film, x is the number of repeating units of the nylon 1 segment; y is the number of repeating units of the piperazine polyamide segment; the piperazine polyamide segment imparts a low dielectric loss to the polyamide film, and the piperazine 12 segment provides excellent mechanical flexibility.

[0010] Preferably, its chemical structure is highly tunable; different degrees of polymerization of nylon 1 segments can be selected, and the molar content of nylon 1 segments can be adjusted; different chemical structures and compositions can be used to prepare polyamides and their films with different dielectric properties.

[0011] Preferably, a preparation method includes the following steps:

[0012] Step 1: Nylon 1 is synthesized by urea self-condensation polymerization; zinc acetate is used as catalyst and the condensation reaction is carried out in a nitrogen atmosphere, followed by heat treatment; different heat treatment conditions can yield nylon 1 with different degrees of polymerization; the stirring speed is set to 100-300 r / min.

[0013] Step 2: Succinic anhydride and nylon 1 obtained in Step 1 were subjected to an end-capping reaction in an autoclave at a molar ratio of 3:1; the product was washed with dichloromethane and filtered, and the filter residue was extracted with ethyl acetate to obtain nylon 1 with carboxyl groups at both ends (hereinafter referred to as "PA1 diacid"); its chemical structure is as follows:

[0014]

[0015] Step 3: The end-capped products PA1 diacid and dodecane diacid obtained in Step 2 are reacted with piperazine at a molar ratio of 1:1.05 to form salts, respectively, to obtain piperazine-PA1 diacid and piperazine-dodecane diacid containing nylon 1 segments.

[0016] Step 4: Piperazine-PA1 diacidate and piperazine-dodecane diacidate are added to an autoclave according to different molar ratios to carry out copolymerization reaction; the reaction process is prepolymerization followed by thickening to obtain a high molecular weight copolymer polyamide; the stirring speed of the autoclave is set to 100-300 r / min.

[0017] Step 5: The copolyamide obtained in Step 4 is hot-pressed or extruded to obtain a dielectric polyamide film containing nylon 1 segments, with the film thickness controlled between 50 and 120 μm.

[0018] Preferably, in step 1, the reaction temperature of the urea self-condensation reaction is 150℃~160℃, the reaction time is 16-30 hours, and nitrogen protection is used during the reaction; zinc acetate is selected as the catalyst in the reaction process. The catalyst can also be an alkaline catalyst such as potassium carbonate, potassium oxide, or sodium carbonate.

[0019] Preferably, in step 1, the heat treatment temperature is 160℃-220℃, the heat treatment time is 4-12 hours, and the heat treatment process is carried out in an atmosphere of 3-5 MPa carbon dioxide.

[0020] Preferably, the nylon 1 structure generated by the polycondensation reaction in step 1 is as follows:

[0021] Where n represents the degree of polymerization of nylon 1, and nylon 1 with different degrees of polymerization is synthesized by controlling the polycondensation reaction and heat treatment time.

[0022] Preferably, the end-capping reaction in step 2 is carried out at a temperature of 110-130°C for 8-24 hours; excess succinic anhydride is washed with dichloromethane, and the resulting product mixture is purified by extraction with ethyl acetate.

[0023] Preferably, in step 3, water is used as the solvent for the salt formation reaction, the reaction temperature is 50-80℃, and the pH value is controlled at 7.2-7.4 after the reaction is completed. The salt solution is concentrated by vacuum distillation, precipitated with ethanol, and dried to obtain nylon dry salt.

[0024] Preferably, the piperazine-PA1 disodium salt and piperazine-dodecane disodium salt containing nylon 1 segments obtained in step 3 are respectively:

[0025]

[0026] Preferably, in step 4, when the piperazine-PA1 diacidate and piperazine-dodecane diacidate containing nylon 1 segments obtained in step 3 are added together to the polymerization reactor for copolymerization, water, catalyst and antioxidant should also be added. The mass of water added is 1 / 2 of the total mass of nylon salt, and the mass of catalyst and antioxidant added is 0.3 to 0.5 wt% of the total mass of nylon salt.

[0027] Preferably, in step 4, the reaction temperature of the prepolymerization reaction is 160-190℃, the reaction time is 2 hours, and the reaction pressure is controlled below the saturated vapor pressure of water, specifically 0.3-0.5 MPa; the thickening reaction temperature is 230℃-250℃, and the reaction is first carried out at constant pressure for 2 hours; then a circulating water vacuum pump is used to evacuate the vacuum to a degree of 0.09 MPa, and the reaction time is 2 hours.

[0028] Preferably, in step 5, the hot pressing process of the nylon film is as follows: first, plasticize at 210℃-230℃ for 10 minutes; then hot press at 210℃-230℃ for 5 minutes at a pressure of 10MPa; and finally cold press at room temperature for 3 minutes at a pressure of 10MPa.

[0029] The beneficial effects of this invention are as follows: Nylon 1 is introduced into the polymer molecular chain as a novel dielectric functional segment by using anhydride end-capping, salt formation, and copolymerization. Compared with the existing reported methods of using nylon 1 as a dielectric functional filler in composite polymer matrices, this eliminates a large number of phase interface problems in composite dielectrics, and the prepared dielectric film has superior comprehensive performance, greatly promoting the application of nylon 1 in film capacitors.

[0030] This invention uses piperazine 12 nylon, which itself does not contain intermolecular hydrogen bonds, as the main chain. Piperazine 12 nylon possesses advantages such as low dielectric loss, excellent mechanical toughness, and good film-forming properties. This invention reports a dielectric polyamide film containing nylon 1 segments, combining the high dielectric constant of nylon 1 with the low dielectric loss and excellent film-forming properties of piperazine nylon, making it of great practical value. An appropriate content of nylon 1 segments also improves the Young's modulus, tensile strength, and breakdown strength of the copolymer.

[0031] Compared with the previously reported dielectric polypropylene or PVDF, the novel dielectric polyamide prepared by this invention has better tunability of chemical structure. It can adjust both the degree of polymerization of nylon 1 and the content of nylon 1 segments, providing a new approach for the chemical structure design of dielectric polymers. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 The infrared spectra of dielectric polyamide films containing nylon 1 segments in Examples 1, 2, and 3 are shown.

[0034] Figure 2 This is a DSC diagram of the dielectric polyamide film containing nylon 1 segments in Example 3.

[0035] Figure 3 The NMR spectra of dielectric polyamides containing nylon 1 segments in Examples 1, 2, and 3 are shown.

[0036] Figure 4 The images show the XRD patterns of dielectric polyamide films containing nylon 1 segments in Examples 1, 2, and 3.

[0037] Figure 5 The graphs show the dielectric constant of the dielectric polyamide films containing nylon 1 segments as a function of frequency in Examples 1, 2, and 3.

[0038] Figure 6 The graphs show the dielectric loss of dielectric polyamide films containing nylon 1 segments as a function of frequency in Examples 1, 2, and 3.

[0039] Figure 7 This is a comparison chart of the dielectric properties of the dielectric polyamide film containing nylon 1 segments prepared in Example 3 and the homopolymer nylon piperazine 12. Detailed Implementation

[0040] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] like Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, a dielectric polyamide film containing nylon 1 segments (abbreviated as Piperazine-PA1) a Preparation method of 7.5%):

[0043] Step 1: Synthesis of Nylon 1. A suitable amount of urea and 5 wt% zinc acetate catalyst were weighed into a round-bottom flask. The mixture was reacted at a constant rate in an oil bath at 155-160℃ for 18 hours under high-purity N2 protection. After the reaction, the heating was turned off, and the mixture was allowed to cool to room temperature. The product was then transferred to a high-pressure reactor at 160℃ for heat treatment for 4 hours under a carbon dioxide atmosphere of 3.5 MPa. The crude product was a white, lumpy solid. Residual urea and catalyst were washed away with deionized water to obtain a white powdery PA1 (degree of polymerization approximately 3.7, abbreviated as PA1). a ).

[0044] Step 2: PA1 a Terminal carboxylation. Weigh PA1 in a molar ratio of 1:3. a Mix the succinic anhydride and butylene glycol thoroughly and pour the mixture into a 1000 mL three-necked flask. Seal the flask, evacuate it, and purge the air into the flask three times with nitrogen. Set the oil bath temperature to 110 °C and the rotation speed to 200 r / min, and maintain the reaction temperature for 12 h. Then, pour the hot reactants into dichloromethane to precipitate and remove excess succinic anhydride. Extract with ethyl acetate to obtain PA1 with carboxyl groups at both ends. a Diacid.

[0045] Step 3: Piperazine-PA1 a Preparation of diacid salts and piperazine-dodecane diacid salts. Weigh the PA1 obtained in step 2 according to the specified proportions. a Dissolve diacid or dodecanoic acid in deionized water with thorough stirring, and then complex with piperazine to form a salt at a constant temperature of 55°C in an oil bath. Monitor the pH value in real time during the gradual addition of piperazine to determine the reaction endpoint. Stop heating when the pH reaches 7.2-7.3 and remains unchanged for half an hour. Stop stirring when the system temperature drops to room temperature. Filter the salt solution again under reduced pressure using rapid filter paper and a Buchner funnel. Place the clear salt solution in a flask in a 60°C water bath for rotary distillation. After completely evaporating the water, transfer and wash the product with anhydrous ethanol. Filter using rapid filter paper and a Buchner funnel, and wash three times with anhydrous ethanol. Dry in an oven at 80°C for 3 hours to obtain piperazine-PA1. a Diasaccharide and piperazine-dodecane diasaccharide.

[0046] Step 4: Copolymerization reaction. Following piperazine-PA1... aThe molar ratio of diacidate to piperazine-dodecanediacidate is 7.5:92.5. Weigh out 20g of the salt obtained in step 3, 10g of deionized water, 0.015g of sodium hypophosphite, and 0.045g of antioxidant 445 into a 100ml tetrafluoroethylene beaker. Place the beaker in a micro autoclave, seal it, evacuate, and purge with nitrogen, circulating 5 times. Turn on the stirrer and set the speed to 300r / min. Heat to 180℃ and react at constant pressure for 2 hours. Open the vent to release the water vapor in the reaction system to atmospheric pressure, then close the vent. Heat to 240℃ and react at constant pressure for 2 hours. Use a circulating water pump to evacuate and maintain the temperature at 240℃ for 2 hours. Use a rotary vane vacuum pump to evacuate and maintain the temperature at 240℃ for 2 hours. Turn off the heating and wait for the reaction system to cool to room temperature. Remove the product, which is a pale yellow, blocky high-molecular-weight copolyamide.

[0047] Step 5: Preparation of dielectric polyamide film containing nylon 1 segment. The copolyamide obtained in Step 4 was first plasticized at 220°C for 10 minutes; then hot-pressed at 220°C for 5 minutes at a pressure of 10 MPa; finally, cold-pressed at room temperature for 3 minutes at a pressure of 10 MPa to obtain a dielectric polyamide film containing nylon 1 segment, with the film thickness controlled at 80±20 μm.

[0048] Following the same synthesis process and auxiliary formulation, only piperazine-dodecanoic acid salt was used to synthesize nylon piperazine 12 homopolymer (abbreviated as Piperazine 12) to compare the improvement of dielectric properties of copolyamide containing nylon 1 segment.

[0049] The Fourier transform infrared (FTIR) spectrum and nuclear magnetic resonance (NMR) spectrum of this product are shown in the attached figures. Figure 1 , Figure 3 As shown in the figure, a copolyamide containing the nylon 1 segment has been successfully synthesized. (Attached) Figure 5 , Figure 6 This indicates that the synthesized copolyamide has excellent dielectric properties.

[0050] Example 2

[0051] like Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, a dielectric polyamide film containing nylon 1 segments (abbreviated as Piperazine-PA1) a Preparation method of 11%):

[0052] Step 1: Synthesis of Nylon 1. A suitable amount of urea and 5 wt% zinc acetate catalyst were weighed into a round-bottom flask. The mixture was reacted at a constant rate in an oil bath at 155-160℃ for 18 hours under high-purity N2 protection. After the reaction, the heating was turned off, and the mixture was allowed to cool to room temperature. The product was then transferred to a high-pressure reactor at 160℃ for heat treatment for 4 hours under a carbon dioxide atmosphere of 3.5 MPa. The crude product was a white, lumpy solid. Residual urea and catalyst were washed away with deionized water to obtain a white powdery PA1 (degree of polymerization approximately 3.7, abbreviated as PA1). a ).

[0053] Step 2: PA1 a Terminal carboxylation. Weigh PA1 in a molar ratio of 1:3. a Mix the succinic anhydride and butylene glycol thoroughly and pour the mixture into a 1000 mL three-necked flask. Seal the flask, evacuate it, and purge the air into the flask three times with nitrogen. Set the oil bath temperature to 110 °C and the rotation speed to 200 r / min, and maintain the reaction temperature for 12 h. Then, pour the hot reactants into dichloromethane to precipitate and remove excess succinic anhydride. Extract with ethyl acetate to obtain PA1 with carboxyl groups at both ends. a Diacid.

[0054] Step 3: Piperazine-PA1 a Preparation of diacid salts and piperazine-dodecane diacid salts. Weigh the PA1 obtained in step 2 according to the specified proportions. a Dissolve diacid or dodecanoic acid in deionized water with thorough stirring, and then complex with piperazine to form a salt at a constant temperature of 55°C in an oil bath. Monitor the pH value in real time during the gradual addition of piperazine to determine the reaction endpoint. Stop heating when the pH reaches 7.2-7.3 and remains unchanged for half an hour. Stop stirring when the system temperature drops to room temperature. Filter the salt solution again under reduced pressure using rapid filter paper and a Buchner funnel. Place the clear salt solution in a flask in a 60°C water bath for rotary distillation. After completely evaporating the water, transfer and wash the product with anhydrous ethanol. Filter using rapid filter paper and a Buchner funnel, and wash three times with anhydrous ethanol. Dry in an oven at 80°C for 3 hours to obtain piperazine-PA1. a Diasaccharide and piperazine-dodecane diasaccharide.

[0055] Step 4: Copolymerization reaction, according to piperazine-PA1 aThe molar ratio of diacidate to piperazine-dodecanediacidate is 11:89. Weigh 20g of the salt obtained in step 3, 30g of deionized water, 0.015g of sodium hypophosphite, and 0.045g of antioxidant 445 into a 100ml tetrafluoroethylene beaker. Place the beaker in a micro autoclave, seal it, evacuate, and purge with nitrogen, circulating the gas 5 times. Turn on the stirrer and set the speed to 300r / min. Raise the temperature to 180℃ and react at constant pressure for 2 hours. Open the vent to release the water vapor in the reaction system to atmospheric pressure, then close the vent. Raise the temperature to 245℃ and react at constant pressure for 2 hours. Use a circulating water pump to evacuate and maintain the temperature at 245℃ for 2 hours. Use a rotary vane vacuum pump to evacuate and maintain the temperature at 245℃ for 2 hours. Turn off the heating and allow the reaction system to cool to room temperature. Remove the product, which is a pale yellow, blocky high-molecular-weight copolyamide.

[0056] Step 5: Preparation of dielectric polyamide film containing nylon 1 segment. The copolyamide obtained in step 4 is first plasticized at 220°C for 10 minutes; then hot-pressed at 220°C for 5 minutes at a pressure of 10 MPa; finally cold-pressed at room temperature for 3 minutes at a pressure of 10 MPa to obtain dielectric polyamide film containing nylon 1 segment. The film thickness is controlled at 80±20 μm.

[0057] Following the same synthesis process and auxiliary formulation, only piperazine-dodecanoic acid salt was used to synthesize nylon piperazine 12 homopolymer (abbreviated as Piperazine 12) to compare the improvement of dielectric properties of copolyamide containing nylon 1 segment.

[0058] The Fourier transform infrared (FTIR) spectrum and nuclear magnetic resonance (NMR) spectrum of this product are shown in the attached figures. Figure 1 , Figure 3 As shown in the figure, a copolyamide containing the nylon 1 segment has been successfully synthesized. (Attached) Figure 5 , Figure 6 This indicates that the prepared copolyamide film has excellent dielectric properties.

[0059] Example 3

[0060] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown, a dielectric polyamide film containing nylon 1 segments (abbreviated as Piperazine12-PA1) a Preparation method of 15%):

[0061] Step 1: Synthesis of Nylon 1. A suitable amount of urea and 5 wt% zinc acetate catalyst were weighed into a round-bottom flask. The mixture was reacted at a constant rate in an oil bath at 155-160℃ for 18 hours under high-purity N2 protection. After the reaction, the heating was turned off, and the mixture was allowed to cool to room temperature. The product was then transferred to a high-pressure reactor at 160℃ for heat treatment for 4 hours under a carbon dioxide atmosphere of 3.5 MPa. The crude product was a white, lumpy solid. Residual urea and catalyst were washed away with deionized water to obtain a white powdery PA1 (degree of polymerization approximately 3.7, abbreviated as PA1). a ).

[0062] Step 2: PA1 a Terminal carboxylation. Weigh PA1 in a molar ratio of 1:3. a Mix the succinic anhydride and butylene glycol thoroughly and pour the mixture into a 1000 mL three-necked flask. Seal the flask, evacuate it, and purge the air into the flask three times with nitrogen. Set the oil bath temperature to 110 °C and the rotation speed to 200 r / min, and maintain the reaction temperature for 12 h. Then, pour the hot reactants into dichloromethane to precipitate and remove excess succinic anhydride. Extract with ethyl acetate to obtain PA1 with carboxyl groups at both ends. a Diacid.

[0063] Step 3: Piperazine-PA1 a Preparation of diacid salts and piperazine-dodecane diacid salts. Weigh the PA1 obtained in step 2 according to the specified proportions. a Dissolve diacid or dodecanoic acid in deionized water with thorough stirring, and then complex with piperazine to form a salt at a constant temperature of 55°C in an oil bath. Monitor the pH value in real time during the gradual addition of piperazine to determine the reaction endpoint. Stop heating when the pH reaches 7.2-7.3 and remains unchanged for half an hour. Stop stirring when the system temperature drops to room temperature. Filter the salt solution again under reduced pressure using rapid filter paper and a Buchner funnel. Place the clear salt solution in a flask in a 60°C water bath for rotary distillation. After completely evaporating the water, transfer and wash the product with anhydrous ethanol. Filter using rapid filter paper and a Buchner funnel, and wash three times with anhydrous ethanol. Dry in an oven at 80°C for 3 hours to obtain piperazine-PA1. a Diasaccharide and piperazine-dodecane diasaccharide.

[0064] Step 4: Copolymerization Reaction. Weigh out 20g of the salt obtained in Step 3, along with 30g of deionized water, 0.015g of sodium hypophosphite, and 0.045g of antioxidant 445, at a molar ratio of 15:85 for piperazine salt containing nylon 1 segments and piperazine-dodecanediate. Add these to a 100ml tetrafluoroethylene beaker. Place the beaker in a miniature autoclave, seal it, evacuate, and purge with nitrogen, repeating the process 5 times. Start the stirrer at 300 rpm. Heat to 180℃ and react at constant pressure for 2 hours. Open the vent to release water vapor from the reaction system to atmospheric pressure, then close the vent. Heat to 250℃ and react at constant pressure for 2 hours. Use a circulating water pump to evacuate and maintain a constant temperature of 250℃ for 2 hours. Use a rotary vane vacuum pump to evacuate and maintain a constant temperature of 250℃ for 2 hours. Turn off the heating and allow the reaction system to cool to room temperature. Remove the product, which is a pale yellow, blocky high-molecular-weight copolyamide.

[0065] Step 5: Preparation of dielectric polyamide film containing nylon 1 segment. The copolyamide obtained in Step 4 was first plasticized at 220°C for 10 minutes; then hot-pressed at 220°C for 5 minutes at a pressure of 10 MPa; finally, cold-pressed at room temperature for 3 minutes at a pressure of 10 MPa to obtain a dielectric polyamide film containing nylon 1 segment, with the film thickness controlled at 80±20 μm.

[0066] Following the same synthesis process and formulation, only piperazine-dodecanoic acid salt was used to synthesize nylon piperazine 12 homopolymer (abbreviated as Piperazine12) to compare the improvement of dielectric properties of copolyamide containing nylon 1 segment.

[0067] The Fourier transform infrared (FTIR) spectrum and nuclear magnetic resonance (NMR) spectrum of this product are shown in the attached figures. Figure 1 , Figure 3 As shown in the figure, a copolyamide containing the nylon 1 segment has been successfully synthesized. (Attached) Figure 5 , Figure 6 , Figure 7 This indicates that the synthesized copolyamide has excellent dielectric properties. The dielectric constant of the copolyamide Piperazine12-PA1 15% is nearly twice that of the matrix nylon piperazine 12, while its dielectric loss remains unchanged.

[0068] Example 4

[0069] A dielectric polyamide film containing nylon 1 segments (abbreviated as Piperazine12-PA1) b Preparation method of 12%):

[0070] Step 1: Synthesis of Nylon 1. Weigh appropriate amounts of urea and 5 wt% zinc acetate catalyst into a round-bottom flask. React at a constant rate in an oil bath at 155-160℃ for 18 hours under high-purity N2 protection. After the reaction, turn off the heating and allow it to cool to room temperature. Remove the product and transfer it to a high-pressure reactor at 160℃ for 2 hours, 170℃ for 4 hours, and 180℃ for 2 hours. The atmosphere in the high-pressure reactor is 4.0-4.5 MPa of carbon dioxide gas. The crude product is a white, lumpy solid. Wash away residual urea and catalyst with deionized water to obtain a white powdery PA1 (degree of polymerization approximately 4.6, abbreviated as PA1). b ).

[0071] Step 2: PA1 b Terminal carboxylation. Weigh PA1 in a molar ratio of 1:3. b Mix the succinic anhydride and butylene glycol thoroughly and pour the mixture into a 1000 mL three-necked flask. Seal the flask, evacuate it, and purge the air into the flask three times with nitrogen. Set the oil bath temperature to 110 °C and the rotation speed to 200 r / min, and maintain the reaction temperature for 12 h. Then, pour the hot reactants into dichloromethane to precipitate and remove excess succinic anhydride. Extract with ethyl acetate to obtain PA1 with carboxyl groups at both ends. b Diacid.

[0072] Step 3: Piperazine-PA1 b Preparation of PA1 diacid salts and piperazine-dodecane diacid salts. Weigh the PA1 obtained in step 2 according to the specified proportions. b Dissolve diacid or dodecanoic acid in deionized water with thorough stirring, and then complex with piperazine to form a salt at a constant temperature of 55°C in an oil bath. Monitor the pH value in real time during the gradual addition of piperazine to determine the reaction endpoint. Stop heating when the pH reaches 7.2-7.3 and remains unchanged for half an hour. Stop stirring when the system temperature drops to room temperature. Filter the salt solution again under reduced pressure using rapid filter paper and a Buchner funnel. Place the clear salt solution in a flask in a 60°C water bath for rotary distillation. After completely evaporating the water, transfer and wash the product with anhydrous ethanol. Filter using rapid filter paper and a Buchner funnel, and wash three times with anhydrous ethanol. Dry in an oven at 80°C for 3 hours to obtain piperazine-PA1. b Diasaccharide and piperazine-dodecane diasaccharide.

[0073] Step 4: Copolymerization reaction. Following piperazine-PA1... bThe molar ratio of the diacidate and piperazine-dodecane diacidate is 12:88. Weigh a total of 20g of the salt obtained in step 3, 30g of deionized water, 0.015g of sodium hypophosphite, and 0.045g of antioxidant 445 into a 100ml tetrafluoroethylene beaker. Place the beaker in a micro autoclave, seal it, evacuate, and purge with nitrogen, circulating the gas 5 times. Turn on the stirrer and set the speed to 300r / min. Raise the temperature to 180℃ and react at constant pressure for 2 hours. Open the vent to release the water vapor in the reaction system to atmospheric pressure, then close the vent. Raise the temperature to 250℃ and react at constant pressure for 2 hours. Use a circulating water pump to evacuate and maintain the temperature at 250℃ for 2 hours. Use a rotary vane vacuum pump to evacuate and maintain the temperature at 250℃ for 2 hours. Turn off the heating and wait for the reaction system to cool to room temperature. Remove the product, which is a pale yellow, blocky high-molecular-weight copolyamide.

[0074] Step 5: Preparation of dielectric polyamide film containing nylon 1 segment. The copolyamide obtained in Step 4 is first plasticized at 220°C for 10 minutes; then hot-pressed at 220°C for 5 minutes at a pressure of 10 MPa; finally, cold-pressed at room temperature for 3 minutes at a pressure of 10 MPa to obtain a dielectric polyamide film containing nylon 1 segment, with the film thickness controlled at 100±20 μm.

[0075] The dielectric constant of the dielectric polyamide film containing nylon 1 segments obtained is 6.4-6.8@(10). 2 -10 5 Dielectric loss 0.002-0.003@(10²-10) 5 ).

[0076] Example 5

[0077] A dielectric polyamide film containing nylon 1 segments (abbreviated as Piperazine12-PA1) b Preparation method of 20%):

[0078] Step 1: Synthesis of Nylon 1. Weigh appropriate amounts of urea and 5 wt% zinc acetate catalyst into a round-bottom flask. React at a constant rate in an oil bath at 155-160℃ for 18 hours under high-purity N2 protection. After the reaction, turn off the heating and allow it to cool to room temperature. Remove the product and transfer it to a high-pressure reactor at 160℃ for 2 hours, 170℃ for 4 hours, and 180℃ for 2 hours. The atmosphere in the high-pressure reactor is 4.0-4.5 MPa of carbon dioxide gas. The crude product is a white, lumpy solid. Wash away residual urea and catalyst with deionized water to obtain a white powdery PA1 (degree of polymerization approximately 4.6, abbreviated as PA1). b ).

[0079] Step 2: PA1 b Terminal carboxylation. Weigh PA1 in a molar ratio of 1:3.b Mix the succinic anhydride and butylene glycol thoroughly and pour the mixture into a 1000 mL three-necked flask. Seal the flask, evacuate it, and purge the air into the flask three times with nitrogen. Set the oil bath temperature to 110 °C and the rotation speed to 200 r / min, and maintain the reaction temperature for 12 h. Then, pour the hot reactants into dichloromethane to precipitate and remove excess succinic anhydride. Extract with ethyl acetate to obtain PA1 with carboxyl groups at both ends. b Diacid.

[0080] Step 3: Piperazine-PA1 b Preparation of PA1 diacid salts and piperazine-dodecane diacid salts. Weigh the PA1 obtained in step 2 according to the specified proportions. b Dissolve diacid or dodecanoic acid in deionized water with thorough stirring, and then complex with piperazine to form a salt at a constant temperature of 55°C in an oil bath. Monitor the pH value in real time during the gradual addition of piperazine to determine the reaction endpoint. Stop heating when the pH reaches 7.2-7.3 and remains unchanged for half an hour. Stop stirring when the system temperature drops to room temperature. Filter the salt solution again under reduced pressure using rapid filter paper and a Buchner funnel. Place the clear salt solution in a flask in a 60°C water bath for rotary distillation. After completely evaporating the water, transfer and wash the product with anhydrous ethanol. Filter using rapid filter paper and a Buchner funnel, and wash three times with anhydrous ethanol. Dry in an oven at 80°C for 3 hours to obtain piperazine-PA1. b Diasaccharide and piperazine-dodecane diasaccharide.

[0081] Step 4: Copolymerization Reaction. Weigh out 20g of the salt obtained in Step 3, along with 30g of deionized water, 0.015g of sodium hypophosphite, and 0.045g of antioxidant 445, according to a molar ratio of 20:80 for piperazine salt containing nylon 1 segments and piperazine-dodecanediate. Add these to a 100ml tetrafluoroethylene beaker. Place the beaker in a micro autoclave, seal it, evacuate, and purge with nitrogen, circulating the gas 5 times. Start the stirrer at 200 rpm. Heat to 180℃ and react at constant pressure for 2 hours. Open the vent to release water vapor from the reaction system to atmospheric pressure, then close the vent. Heat to 250℃ and react at constant pressure for 2 hours. Use a circulating water pump to evacuate and maintain a constant temperature of 250℃ for 2 hours. Use a rotary vane vacuum pump to evacuate and maintain a constant temperature of 250℃ for 2 hours. Turn off the heating and allow the reaction system to cool to room temperature. Remove the product, which is a pale yellow, blocky high-molecular-weight copolyamide.

[0082] Step 5: Preparation of dielectric polyamide film containing nylon 1 segment. The copolyamide obtained in Step 4 is first plasticized at 230°C for 10 minutes; then hot-pressed at 230°C for 5 minutes at a pressure of 10 MPa; finally, cold-pressed at room temperature for 3 minutes at a pressure of 10 MPa to obtain a dielectric polyamide film containing nylon 1 segment, with the film thickness controlled at 100±20 μm.

[0083] The dielectric constant of the dielectric polyamide film containing nylon 1 segments obtained is 7.2-7.6@(10). 2 -10 5 Dielectric loss 0.002-0.003@(10) 2 -10 5 ).

[0084] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A copolyamide containing nylon 1 segments and possessing dielectric properties, characterized in that: The structural formula is: Where n = 3-8, x is the number of repeating units in the nylon 1 segment, and y is the number of repeating units in the piperazine polyamide segment.

2. A preparation method for preparing the dielectric polyamide film containing nylon 1 segments as described in claim 1, characterized in that: Includes the following steps: Step 1: Nylon 1 is synthesized by urea self-condensation polymerization; zinc acetate is used as catalyst and the condensation reaction is carried out in a nitrogen atmosphere, followed by heat treatment; different heat treatment conditions can yield nylon 1 with different degrees of polymerization, wherein the stirring speed is set to 100-300 r / min; Step 2: Succinic anhydride and nylon 1 obtained in Step 1 were subjected to an end-capping reaction in an autoclave at a molar ratio of 3:1; the product was washed with dichloromethane and extracted with ethyl acetate to obtain nylon 1 with carboxyl groups at both ends, namely: PA1 diacid, whose chemical structure is as follows: Step 3: Piperazine is reacted with PA1 diacid and dodecanoic acid obtained in Step 2 at a molar ratio of 1.05:1 to form salts, yielding piperazine-PA1 diacid and piperazine-dodecanoic acid. Step 4: Piperazine-PA1 diacidate and piperazine-dodecane diacidate are added to an autoclave in a certain proportion to carry out a copolymerization reaction; the reaction process is prepolymerization followed by thickening to obtain a high molecular weight copolymer polyamide; the stirring speed of the autoclave is set to 100-300 r / min. Step 5: The copolyamide obtained in Step 4 is hot-pressed to obtain a dielectric polyamide film containing nylon 1 segments, with the film thickness controlled between 50 and 120 μm.

3. The preparation method according to claim 2, characterized in that: In step 1, the reaction temperature of the urea self-condensation reaction is 150℃-160℃, the reaction time is 16-30 hours, and nitrogen protection is used during the reaction.

4. The preparation method according to claim 2, characterized in that: In step 1, the heat treatment temperature is 160℃-220℃, the heat treatment time is 4-12 hours, and the heat treatment process is carried out in an atmosphere of 3-5MPa carbon dioxide.

5. The preparation method according to claim 2, characterized in that: The structure of nylon 1 generated by the polycondensation reaction in step 1 is as follows: Where n represents the degree of polymerization of nylon 1, and nylon 1 with different degrees of polymerization is synthesized by controlling the heat treatment temperature and time.

6. The preparation method according to claim 2, characterized in that: The end-capping reaction in step 2 is carried out at a temperature of 110-130℃ for 8-24 hours. Excess succinic anhydride is washed with dichloromethane, and the resulting product mixture is purified by extraction with ethyl acetate.

7. The preparation method according to claim 2, characterized in that: In step 3, water is used as the solvent for all salt formation reactions, the reaction temperature is 50-80℃, and the pH value is controlled at 7.2-7.3 after the reaction is completed. The salt solution is concentrated by vacuum distillation, precipitated with ethanol, and dried to obtain nylon dry salt.

8. The preparation method according to claim 2, characterized in that: The piperazine-PA1 disodium and piperazine-dodecane disodium obtained by the salt formation reaction in step 3 are respectively:

9. The preparation method according to claim 2, characterized in that: In step 4, when the piperazine-polyamide salt and piperazine-dodecanoate salt containing nylon 1 segments obtained in step 3 are added together to the polymerization reactor for copolymerization, water, catalyst and antioxidant should also be added. The mass of water added is 1 / 2 of the total mass of nylon salt, and the mass of catalyst and antioxidant added is 0.3-0.5 wt% of the total mass of nylon salt.

10. The preparation method according to claim 2, characterized in that: In step 4, the prepolymerization reaction temperature is 160-190℃, the reaction time is 2 hours, and the reaction pressure is controlled below the saturated vapor pressure of water, specifically 0.3-0.5 MPa; the thickening reaction temperature is 230℃-250℃, and the reaction is first carried out at constant pressure for 2 hours; then a circulating water vacuum pump is used to evacuate the vacuum to a degree of 0.09 MPa, and the reaction time is 2 hours.

11. The preparation method according to claim 2, characterized in that: In step 5, the hot pressing process of the film is as follows: first, plasticize at 210℃-230℃ for 10 minutes; then hot press at 210℃-230℃ for 5 minutes at a pressure of 10MPa; finally, cold press at room temperature for 3 minutes at a pressure of 10MPa.

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