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CN-116675852-B - Copolyamide containing nylon 1 chain segment and having dielectric function and preparation method thereof

CN116675852BCN 116675852 BCN116675852 BCN 116675852BCN-116675852-B

Abstract

The invention belongs to the technical field of synthesis of all-organic polymer dielectric films, and particularly relates to copolyamide containing nylon 1 chain segments and a preparation method thereof, wherein the preparation method of the dielectric polyamide film containing nylon 1 chain segments comprises the following steps of nylon 1 synthesis with different polymerization degrees, succinic anhydride end-capped nylon 1, end-capped products (PA 1 diacid for short) and piperazine salifying, copolycondensation reaction of piperazine-PA 1 diacid salt and piperazine-dodecanedioic acid salt, hot press molding and the like. In the invention, piperazine-PA 1 diacid salt and piperazine-dodecanedioic acid salt are copolycondensed at high temperature and high pressure, and nylon 1 is taken as a dielectric functional chain segment to be embedded into a piperazine nylon matrix by combining the high dielectric constant of the nylon 1 chain segment and the unique low dielectric loss of piperazine nylon, and the dielectric polyamide film containing the nylon 1 chain segment is directly prepared through simple hot press molding.

Inventors

  • CAI XUFU
  • HUANG LEI
  • ZENG FANHAO
  • KONG WEIBO

Assignees

  • 四川大学

Dates

Publication Date
20260508
Application Date
20230606

Claims (11)

  1. 1. A copolyamide with dielectric function containing nylon 1 chain segment is characterized in that the structural formula is: wherein n=3-8,x is the number of the repeated units of the nylon 1 chain segment, and y is the number of the repeated units of the piperazine polyamide chain segment.
  2. 2. A process for preparing the dielectric polyamide film containing nylon 1 segment according to claim 1, comprising the steps of: Step 1, synthesizing nylon 1 by adopting a urea self-polycondensation method, carrying out polycondensation reaction in a nitrogen atmosphere by adopting zinc acetate as a catalyst, and then carrying out heat treatment, wherein the heat treatment conditions are different, and nylon 1 with different polymerization degrees can be obtained, and the stirring rotation speed is set to be 100-300r/min; Step 2, carrying out end-capping reaction on succinic anhydride and nylon 1 prepared in the step 1 in an autoclave according to a molar ratio of 3:1, washing a product with methylene dichloride, and extracting with ethyl acetate to obtain nylon 1 with carboxyl at two ends, namely PA1 diacid, wherein the chemical structure of the nylon 1 is as follows: step 3, performing salt formation reaction on piperazine and the PA1 diacid and the dodecanedioic acid prepared in the step 2 according to a molar ratio of 1.05:1 to obtain piperazine-PA 1 diacid salt and piperazine-dodecanedioic acid salt; step 4, adding piperazine-PA 1 diacid salt and piperazine-dodecanedioic acid salt into an autoclave according to a certain proportion to carry out copolymerization reaction, wherein the reaction process is that prepolymerization is carried out firstly, then tackifying is carried out, and copolyamide with high molecular weight is obtained, wherein the stirring speed of the autoclave is set to be 100-300r/min; And 5, carrying out hot press molding on the copolyamide obtained in the step 4 to obtain the dielectric polyamide film containing the nylon 1 chain segment, wherein the thickness of the film is controlled to be 50-120 mu m.
  3. 3. The method of claim 2, wherein in step 1, the reaction temperature of the urea auto-polycondensation reaction is 150-160 ℃, the reaction time is 16-30 hours, and nitrogen protection is adopted in the reaction process.
  4. 4. The method of claim 2, wherein in step 1, the heat treatment temperature is 160-220 ℃, the heat treatment time is 4-12 hours, and the heat treatment process uses 3-5MPa carbon dioxide as atmosphere.
  5. 5. The method of claim 2, wherein the nylon 1 produced by the polycondensation reaction in step 1 has the structure: wherein n represents the polymerization degree of nylon 1, and specifically nylon 1 having different polymerization degrees is synthesized by controlling the heat treatment temperature and time.
  6. 6. The preparation method according to claim 2, wherein the reaction temperature of the end capping reaction in the step 2 is 110-130 ℃ and the reaction time is 8-24 hours, and washing the excessive succinic anhydride with methylene dichloride to obtain a product mixture, extracting the product mixture with ethyl acetate and purifying the product mixture.
  7. 7. The preparation method of the nylon dry salt is characterized in that water is used as a solvent in the salt forming reaction in the step 3, the reaction temperature is 50-80 ℃, the pH value is controlled to be 7.2-7.3 after the reaction is finished, and the salt solution is concentrated by reduced pressure distillation, ethanol precipitation and drying treatment to obtain the nylon dry salt.
  8. 8. The preparation method of claim 2, wherein the piperazine-PA 1 diacid salt and piperazine-dodecanedioic acid salt containing nylon 1 chain segments prepared by the salification reaction in the step 3 are respectively:
  9. 9. The preparation method of the nylon salt according to claim 2, wherein in the step 4, water, a catalyst and an antioxidant are added when the piperazine-polyamide salt containing the nylon 1 chain segment and the piperazine-dodecanedioic acid salt obtained in the step 3 are added into a polymerization reaction kettle together for copolymerization reaction, wherein the mass of the added water is 1/2 of the total mass of the nylon salt, and the mass of the added catalyst and antioxidant are respectively 0.3-0.5 wt% of the total mass of the nylon salt.
  10. 10. The preparation method of the catalyst according to claim 2, wherein in the step 4, the reaction temperature of the prepolymerization is 160-190 ℃, the reaction time is 2 hours, the reaction pressure is controlled below the saturated vapor pressure of water, specifically 0.3-0.5MPa, the tackifying reaction temperature is 230-250 ℃, the reaction is carried out for 2 hours at constant pressure, the vacuum pumping is carried out by adopting a circulating water type vacuum pump, the vacuum degree is 0.09MPa, and the reaction time is 2 hours.
  11. 11. The method of claim 2, wherein in step 5, the film is plasticized at 210-230 ℃ for 10 minutes, heated at 210-230 ℃ for 5 minutes, at 10MPa, and finally cooled at room temperature for 3 minutes at 10MPa.

Description

Copolyamide containing nylon 1 chain segment and having dielectric function and preparation method thereof Technical Field The invention belongs to the technical field of synthesis of all-organic polymer dielectric films, and particularly relates to a copolyamide containing nylon 1 chain segments and having a dielectric function and a preparation method thereof. Background The polymer film capacitor is widely applied to the fields of electric automobiles, pulse power systems, smart grids and the like due to the advantages of easiness in processing, high voltage resistance and the like. Biaxially oriented polypropylene (BOPP) has been the most popular polymer dielectric at present for decades due to its low dielectric loss (tan delta < 0.003), high breakdown strength (> 500 MV/m). However, its low dielectric constant (1.8-2.2) results in its low energy storage density, which severely hampers its application in advanced pulse electronics. Therefore, new generation polymer film capacitor applications are in urgent need for dielectric polymers with high dielectric constants. Nylon 1, i.e. PAI, also known as polycarbonyl urea, has the chemical structureThe nylon material having the highest dielectric constant is theoretically the nylon material having the highest density of amide groups and hydrogen bond density in polyamides. The maximum dielectric constant can reach 30-40@10 2-105 after proper heat treatment. However, nylon 1 is generally a rigid powder that is difficult to process into a film due to its high molecular chain rigidity and strong intermolecular forces, which greatly limits its application as a dielectric functional material. The inventor tries to directly add nylon 1 as a dielectric function filler into PVDF and nylon 11 matrixes, and the dielectric constants of the prepared composite dielectric medium are obviously improved. However, the introduction of nylon 1 also causes a large number of phase interfaces, which results in a large dielectric loss of the composite dielectric, and is difficult to be practically used. No similar method for solving the above problems has been reported in the literature. By means of the copolymerization, it is possible to combine the corresponding excellent properties of the individual structural units and without this leading to complex phase interfaces in similar composites. Therefore, nylon 1 is introduced as a dielectric functional segment into a molecular chain of a polymer having low dielectric loss and excellent mechanical properties, and it is expected to combine the high dielectric constant of nylon 1 with the low dielectric loss of other polymers and excellent film forming properties. Nylon Long Paiqin-12 with low dielectric loss and excellent mechanical property is selected as a basic polymer, nylon 1 is used as a functional structural unit, and the nylon 1 is subjected to end sealing, salifying with piperazine, and then is copolymerized with piperazine-dodecanedioic acid salt, so that the dielectric polyamide film containing nylon 1 chain segments is prepared through simple combination and hot pressing or extrusion molding. The comprehensive performance of the obtained dielectric film can be easily adjusted by selecting nylon 1 with different polymerization degrees and adjusting the mole content of nylon 1 chain segments. The polyamide film prepared by the method has high dielectric constant, low dielectric loss and excellent mechanical toughness, and provides a new thought for chemical structural design of dielectric polymers. Disclosure of Invention The invention provides a method for preparing a dielectric polyamide film containing nylon 1 chain segments, which solves the problems that the dielectric constant of the existing polymer dielectric is low and the nylon 1 reported at present is difficult to thin. According to the invention, nylon 1 chain segments with different lengths or molar contents are introduced into the molecular chain of nylon piperazine-12, and the combination of the high dielectric constant of the nylon 1 chain segments and the low dielectric loss and excellent mechanical properties of piperazine long-chain diacid nylon greatly promotes the application of nylon 1 as a novel dielectric functional material in the field of film capacitors, and provides a new thought and method for the chemical structural design of dielectric polymers. In order to achieve the purpose, the invention provides the following technical scheme that the copolyamide containing nylon 1 chain segments and having a dielectric function has the structural formula as follows: Wherein n=3-8, the nylon 1 chain segment gives the polyamide film a high dielectric constant, x is the number of the repeated units of the nylon 1 chain segment, y is the number of the repeated units of the piperazine polyamide chain segment, the piperazine polyamide chain segment gives the polyamide film a low dielectric loss, and the piperazine 12 chain segment provides excellent mechanica