Epoxy impregnated aramid fiber composite paper treatment method based on non-thermal atmosphere plasma

Abstract

The invention relates to the technical field of material surface treatment, and discloses an epoxy impregnated aramid fiber composite paper treatment method based on non-thermal atmospheric plasmas, aramid fiber composite paper, a heterocyclic aramid fiber solution, an epoxy resin prepolymer, a curing agent and a solvent are prepared, after the aramid fiber composite paper is subjected to surface cleaning, non-thermal atmospheric plasma treatment is carried out, and the surface of the aramid fiber composite paper is dried to obtain the epoxy impregnated aramid fiber composite paper. The preparation method comprises the following steps: preparing a heterocyclic aramid solution, putting aramid composite paper into the heterocyclic aramid solution, carrying out primary impregnation, carrying out drying and curing after impregnation, preparing an epoxy resin prepolymer, putting the aramid composite paper into the epoxy resin prepolymer, carrying out secondary impregnation, removing excess resin after impregnation, and preparing the aramid composite paper with the excess resin removed, according to the method, the non-thermal atmosphere plasma treatment technology and the step-by-step impregnation technology are combined, the synergistic effect of heterocyclic aramid and epoxy resin can be fully exerted, and therefore the interface adhesive force between fibers is improved.

Description

Technical Field

[0001] The invention relates to the technical field of material surface treatment, in particular to a method for treating epoxy-impregnated aramid composite paper based on non-thermal atmospheric plasma. Background Art

[0002] In the existing surface treatment technology of epoxy impregnated aramid composite paper (HA / PAP), although the treated aramid composite paper has excellent mechanical properties and insulation properties, there are still some technical defects. The main problem is the low interfacial adhesion between the fibers, resulting in poor densification of the paper structure. This insufficient interfacial bonding not only limits the overall performance of the composite material, but also makes the HA-impregnated PAP perform poorly in mechanical properties, such as insufficient tensile strength and anti-delamination ability. In addition, due to the smooth surface and high crystallinity of aramid fibers, there is a lack of polar groups that bind to the resin matrix, resulting in poor resin impregnation, which further affects the interfacial properties of the aramid composite paper.

[0003] All-para-aramid paper has important applications in the field of special honeycomb material manufacturing due to its excellent mechanical properties and thermal stability. The present invention introduces a simple method for preparing high-performance all-para-aramid paper. The method involves impregnating a heterocyclic aramid (HA) solution into a para-aramid paper (PAP) made of poly(terephthalamide) staple fibers (PPTA) and polymerization-induced para-aramid nanofibers (PANF).

[0004] To verify the successful adhesion of the HA coating on the paper surface and its penetration into the PAP, the researchers used field emission scanning electron microscopy and micro Fourier transform infrared spectroscopy. Since the HA molecule is similar in structure to the PPTA molecule in solution and its ability to form hydrogen bonds far exceeds that of PPTA fibers, the HA molecule can effectively act as a binder between the two PPTA fibers. This not only enhances the interfacial adhesion between the fibers, but also promotes the densification of the paper structure. These structural improvements, coupled with the excellent mechanical properties of HA itself, make the HA-impregnated PAP (HA / PAP) significantly superior to the untreated PAP in terms of mechanical properties. Specifically, the tensile strength of HA / PAP can reach 128.5 MPa, which is 4.8 times that of pure PAP; its internal bonding strength can reach 356.1 J / m2, which is 4.5 times that of pure PAP, significantly improving the anti-delamination ability. In addition, the all-para-aramid HA / PAP also exhibits excellent thermal stability and flame retardancy. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the shortcomings of the prior art, the present invention provides an epoxy impregnated aramid composite paper processing method based on non-thermal atmospheric plasma, which has the advantage of high interfacial adhesion between fibers and solves the problem of low interfacial adhesion between fibers in the existing surface treatment methods of aramid composite paper.

[0007] (II) Technical solution

[0008] To achieve the above object, the present invention provides the following technical solution: a method for treating epoxy-impregnated aramid composite paper based on non-thermal atmospheric plasma, comprising the following steps:

[0009] Step 1: Material preparation: aramid composite paper, heterocyclic aramid solution, epoxy resin prepolymer, curing agent and solvent;

[0010] Step 2, pretreatment stage: After cleaning the surface of the aramid composite paper, non-thermal atmospheric plasma treatment is performed;

[0011] Step 3, impregnation of heterocyclic aramid: preparing a heterocyclic aramid solution, placing the aramid composite paper into the heterocyclic aramid solution, performing a first impregnation, and drying and curing after the impregnation;

[0012] Step 4: Epoxy resin impregnation: preparing epoxy resin prepolymer, placing the aramid composite paper into the epoxy resin prepolymer, and performing a second impregnation, and removing excess resin after impregnation;

[0013] Step 5: Post-processing: The aramid composite paper with excess resin removed is subjected to curing, demoulding and finishing treatments;

[0014] Step 6: Performance testing: Perform performance testing on the aramid composite paper after fine finishing.

[0015] Preferably, in the surface cleaning process of step 2, the aramid composite paper is placed in ethanol for ultrasonic cleaning for 30-45 minutes, taken out, and then cleaned with deionized water for 5-8 times, and the aramid composite paper is blown dry with nitrogen.

[0016] Preferably, the non-thermal atmospheric plasma treatment process in step 2:

[0017] S2.1, placing the dried aramid composite paper into a non-thermal atmospheric plasma device for plasma treatment;

[0018] S2.2. Set the plasma treatment time of the non-thermal atmospheric plasma equipment to 10-15 minutes and the power to 150-200W.

[0019] Preferably, the preparation process of the heterocyclic aramid solution in step 3 is:

[0020] S3.1. Prepare the reagents: terephthaloyl chloride, p-phenylenediamine, 5(6)-amino-2-(4-aminophenyl)benzimidazole, N,N-dimethylacetamide, dimethyl sulfoxide and lithium chloride;

[0021] S3.2, polymerization process: add lithium chloride to a reactor, set the reactor temperature to 0-3°C, add p-phenylenediamine and 5(6)-amino-2-(4-aminophenyl)benzimidazole, stir for 10-15 minutes until completely dissolved, first add 4 / 5 of terephthaloyl chloride for the first stage reaction, the reaction time is 45-50 minutes, then raise the reactor temperature to 20-30°C, add 1 / 5 of terephthaloyl chloride for the second stage reaction, the reaction time is 25-30 minutes, after the reaction is complete, a heterocyclic aramid solution is obtained.

[0022] Preferably, in step three, the immersion time of the aramid composite paper in the heterocyclic aramid solution is 55-65 minutes.

[0023] Preferably, in the drying and curing process in step three, the impregnated aramid composite paper is taken out, preliminarily dried with nitrogen, dried in an oven at 65-70°C for 8-12 minutes, and then subjected to a pressure of 1.5-2MPa at 155-160°C for hot pressing curing for 1.5-1.8 hours.

[0024] Preferably, the preparation process of the epoxy resin prepolymer in step 4 is:

[0025] S4.1. Select reagents: select bisphenol A epoxy resin and hydrogen-containing silane as the base reagents;

[0026] S4.2. Equipment selection: reactor;

[0027] S4.3, epoxidation reaction conditions: set the reactor temperature to 80-180°C, and the reactor reaction time to 35-55 minutes;

[0028] S4.4, condensation reaction: add bisphenol A epoxy resin and hydrogen-containing silane into a reaction kettle to react to form a linear molecular structure, and finally obtain an epoxy resin prepolymer.

[0029] Preferably, in step 4, the aramid composite paper is immersed in the epoxy resin prepolymer for a second time, and the immersion time is 1-1.2 hours.

[0030] Preferably, in the process of removing excess resin from the aramid composite paper in step 4, the impregnated aramid composite paper is placed between two parallel flat plates, and a pressure of 100-150 Pa is applied to the flat plates by an air pressure device to squeeze out excess epoxy resin.

[0031] Preferably, the curing conditions in step five are: setting the curing temperature to 160-165° C., setting the curing pressure to 2-2.5 MPa, and setting the curing time to 1.0-1.3 h.

[0032] Compared with the prior art, the present invention provides a method for treating epoxy-impregnated aramid composite paper based on non-thermal atmospheric plasma, which has the following beneficial effects:

[0033] 1. The present invention helps to improve the comprehensive performance of aramid composite paper by adopting non-thermal atmospheric plasma treatment combined with a step-by-step impregnation process of heterocyclic aramid (HA) and epoxy resin prepolymer. Among them, the non-thermal atmospheric plasma treatment can effectively enhance the activity of the fiber surface, thereby improving the interfacial adhesion between the fibers. At the same time, the preparation of the heterocyclic aramid solution and the preparation process of the epoxy resin prepolymer after optimizing the conditions can further improve the bonding force between the fiber and the resin, making the paper structure more compact. The higher prepolymer reaction temperature and extended impregnation time in the preparation process of the epoxy resin prepolymer help to form a tighter network structure between the aramid composite paper and the epoxy resin, thereby improving the thermal stability of the composite paper. In terms of flame retardant properties, the present invention can give full play to the synergistic effect of heterocyclic aramid and epoxy resin through a step-by-step impregnation process to improve the flame retardant properties of the aramid composite paper. Therefore, the treatment method of the present invention can effectively improve the interfacial adhesion, thermal stability, flame retardancy and mechanical properties of the aramid composite paper. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figure 1 , a method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma, comprising the following steps:

[0037] Step 1: Material preparation: aramid composite paper, heterocyclic aramid (HA) solution, epoxy resin prepolymer, curing agent and solvent;

[0038] Step 2, pretreatment stage: After cleaning the surface of the aramid composite paper, non-thermal atmospheric plasma treatment is performed;

[0039] Step 3, impregnation with heterocyclic aramid (HA): preparing a heterocyclic aramid (HA) solution, placing the aramid composite paper into the heterocyclic aramid (HA) solution, performing a first impregnation, and drying and curing after the impregnation;

[0040] Step 4: Epoxy resin impregnation: preparing epoxy resin prepolymer, placing the aramid composite paper into the epoxy resin prepolymer, and performing a second impregnation, and removing excess resin after impregnation;

[0041] Step 5: Post-processing: The aramid composite paper with excess resin removed is subjected to curing, demoulding and finishing treatments;

[0042] Step 6: Performance testing: Perform performance testing on the aramid composite paper after fine finishing.

[0043] Specifically, in step 2, the surface cleaning process is as follows: the aramid composite paper is placed in ethanol for ultrasonic cleaning for 30-45 minutes to remove surface impurities and dust, and then taken out and cleaned with deionized water for 5-8 times, and the aramid composite paper is blown dry with nitrogen.

[0044] Specifically, the non-thermal atmospheric plasma treatment process in step 2 is:

[0045] S2.1, placing the blow-dried aramid composite paper into a non-thermal atmospheric plasma device for plasma treatment. The plasma treatment can increase the roughness of the fiber surface and improve its surface energy, thereby enhancing the adhesion of the subsequent coating;

[0046] S2.2. Set the plasma treatment time of the non-thermal atmospheric plasma equipment to 10-15 minutes and the power to 150-200W.

[0047] Specifically, the preparation process of the heterocyclic aramid (HA) solution in step 3 is:

[0048] S3.1. Prepare reagents: terephthaloyl chloride (TPC), p-phenylenediamine (PPD), 5(6)-amino-2-(4-aminophenyl)benzimidazole (PABZ), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO) and lithium chloride (LiCl);

[0049] S3.2, polymerization process: add lithium chloride (LiCl) into a reactor, set the reactor temperature to 0-3°C, add p-phenylenediamine (PPD) and 5(6)-amino-2-(4-aminophenyl)benzimidazole (PABZ), stir for 10-15 minutes until completely dissolved, first add 4 / 5 of terephthaloyl chloride for the first stage reaction, the reaction time is 45-50 minutes, then raise the reactor temperature to 20-30°C, and then add 1 / 5 of terephthaloyl chloride for the second stage reaction, the reaction time is 25-30 minutes, after the reaction is complete, a heterocyclic aramid solution is obtained.

[0050] Specifically, in step 3, the immersion time of the aramid composite paper in the heterocyclic aramid (HA) solution is 55-65 minutes.

[0051] Specifically, in the drying and curing process in step three: the impregnated aramid composite paper is taken out, initially dried with nitrogen, dried in an oven at 65-70°C for 8-12 minutes, and then subjected to a pressure of 1.5-2MPa at 155-160°C for 1.5-1.8 hours of hot pressing curing.

[0052] Specifically, the preparation process of the epoxy resin prepolymer in step 4 is as follows:

[0053] S4.1. Select reagents: select bisphenol A epoxy resin and hydrogen-containing silane as the base reagents;

[0054] S4.2. Equipment selection: reactor;

[0055] S4.3, epoxidation reaction conditions: set the reactor temperature to 80-180°C, and the reactor reaction time to 35-55 minutes;

[0056] S4.4, condensation reaction: add bisphenol A epoxy resin and hydrogen-containing silane into a reaction kettle to react to form a linear molecular structure, and finally obtain an epoxy resin prepolymer.

[0057] Specifically, in step 4, the aramid composite paper is immersed in the epoxy resin prepolymer for a second time, and the immersion time is 1-1.2 hours.

[0058] Specifically, in step 4, the process of removing excess resin from the aramid composite paper is as follows: the impregnated aramid composite paper is placed between two parallel flat plates, and a pressure of 100-150Pa is applied to the flat plates through an air pressure device to squeeze out excess epoxy resin. This process makes the flat plates fit tightly together, thereby squeezing out excess epoxy resin. The surface of the flat plates usually needs to be flat and smooth to ensure that the paper is evenly stressed during the extrusion process. This step can prevent an excessively thick resin layer on the surface from affecting performance.

[0059] Specifically, the curing conditions in step five are: setting the curing temperature to 160-165° C., setting the curing pressure to 2-2.5 MPa, and setting the curing time to 1.0-1.3 h.

[0060] Example 1

[0061] Material preparation: prepare aramid composite paper, heterocyclic aramid (HA) solution, epoxy resin prepolymer, curing agent and solvent;

[0062] Preprocessing stage:

[0063] Surface cleaning: Place the aramid composite paper in ethanol and perform ultrasonic cleaning for 30 minutes to remove impurities and dust. After taking it out, wash it with deionized water for 5 times and then blow it dry with nitrogen.

[0064] Non-thermal atmospheric plasma treatment: Place the dried aramid composite paper into the non-thermal atmospheric plasma equipment, set the treatment time to 10 min, and the power to 150 W;

[0065] Heterocyclic aramid (HA) impregnation:

[0066] Preparation of heterocyclic aramid (HA) solution: lithium chloride (LiCl) was added into the reactor, the temperature was set to 0°C, p-phenylenediamine (PPD) and 5(6)-amino-2-(4-aminophenyl)benzimidazole (PABZ) were added, stirred for 10 min until completely dissolved, 4 / 5 of terephthaloyl chloride was added and reacted for 45 min, then the temperature was raised to 20°C, 1 / 5 of terephthaloyl chloride was added and reacted for 25 min to obtain a heterocyclic aramid solution;

[0067] Impregnation: The aramid composite paper was immersed in the heterocyclic aramid (HA) solution for 55 minutes, taken out and dried with nitrogen, dried in an oven at 65°C for 8 minutes, and then hot-pressed and cured at 155°C and 1.5MPa for 1.5 hours;

[0068] Epoxy resin impregnation:

[0069] Preparation of epoxy resin prepolymer: using bisphenol A epoxy resin and hydrogen-containing silane as basic reagents, in a reaction kettle, the temperature is set to 80°C, the reaction is carried out for 35 minutes, a linear molecular structure is formed, and an epoxy resin prepolymer is obtained;

[0070] Impregnation and removal of excess resin: The aramid composite paper was immersed in the epoxy resin prepolymer for 1 hour, and then placed between two parallel plates. A pressure of 100 Pa was applied to the plates by an air pressure device to squeeze out the excess epoxy resin.

[0071] Post-treatment: curing at 160℃ and 2MPa pressure for 1h, followed by demoulding and finishing;

[0072] Performance testing: Perform performance testing on the aramid composite paper after fine finishing.

[0073] Example 2

[0074] Material preparation: same as Example 1;

[0075] Preprocessing stage:

[0076] Surface cleaning: Place the aramid composite paper in ethanol and ultrasonically clean it for 45 minutes to remove impurities and dust. After taking it out, wash it with deionized water for 8 times and then blow it dry with nitrogen;

[0077] Non-thermal atmospheric plasma treatment: Place the dried aramid composite paper into the non-thermal atmospheric plasma equipment, set the treatment time to 15 min, and the power to 200 W;

[0078] Heterocyclic aramid (HA) impregnation:

[0079] Preparation of heterocyclic aramid (HA) solution: lithium chloride (LiCl) was added into the reactor, the temperature was set at 3°C, p-phenylenediamine (PPD) and 5(6)-amino-2-(4-aminophenyl)benzimidazole (PABZ) were added, stirred for 15 min until completely dissolved, 4 / 5 of terephthaloyl chloride was added and reacted for 50 min, then the temperature was raised to 30°C, 1 / 5 of terephthaloyl chloride was added and reacted for 30 min to obtain a heterocyclic aramid solution;

[0080] Impregnation: The aramid composite paper was immersed in the heterocyclic aramid (HA) solution for 65 minutes, taken out and dried with nitrogen, dried in an oven at 70°C for 12 minutes, and then hot-pressed and cured at 160°C and 2MPa for 1.8 hours;

[0081] Epoxy resin impregnation:

[0082] Preparation of epoxy resin prepolymer: using bisphenol A epoxy resin and hydrogen-containing silane as basic reagents, in a reaction kettle, the temperature is set to 180°C, the reaction is carried out for 55 minutes, a linear molecular structure is formed, and an epoxy resin prepolymer is obtained;

[0083] Impregnation and removal of excess resin: The aramid composite paper was immersed in the epoxy resin prepolymer for 1.2 h, and then placed between two parallel plates. A pressure of 150 Pa was applied to the plates by an air pressure device to squeeze out the excess epoxy resin.

[0084] Post-treatment: curing at 165°C and 2.5MPa pressure for 1.3h, followed by demoulding and finishing.

[0085] Performance testing: Perform performance testing on the aramid composite paper after fine finishing.

[0086] Comparative Example 1 (Traditional Method 1)

[0087] Material preparation: same as Example 1;

[0088] Pretreatment stage: rinse the aramid composite paper with clean water only and let it dry naturally;

[0089] Dipping treatment: directly put the aramid composite paper into ordinary epoxy resin without special formulation and immerse it for 30 minutes, then take it out and let the excess resin drip off naturally;

[0090] Post-treatment: Curing at 120℃ for 2h, followed by demoulding and simple trimming;

[0091] Performance testing: Perform performance testing on the treated aramid composite paper.

[0092] Comparative Example 2 (Traditional Method 2)

[0093] Material preparation: same as Example 1;

[0094] Pretreatment stage: Soak the aramid composite paper in acetone for 15 minutes, take it out and rinse it with clean water for 3 times, and blow dry it with a hair dryer at low temperature;

[0095] Dipping treatment: put the aramid composite paper into the pre-mixed conventional heterocyclic aramid and epoxy resin mixture for 40 minutes, and then absorb the excess liquid with filter paper;

[0096] Post-treatment: curing at 140°C and 1MPa for 1.5h, followed by demoulding and simple trimming;

[0097] Performance testing: Perform performance testing on the treated aramid composite paper.

[0098] The aramid composite paper of the present invention was subjected to surface treatment in the embodiment and the comparative example, and then subjected to performance testing, and the following test results were obtained:

[0099] Table 1

[0100]

[0101]

[0102] The following information is obtained from the above table:

[0103] Interfacial bonding strength between fibers: Since Examples 1 and 2 used non-thermal atmospheric plasma treatment and heterocyclic aramid impregnation, the interfacial bonding strength between fibers was higher than that of the comparative example, and the bonding strength of the paper tested in Example 2 was higher than that of Example 1 because the non-thermal atmospheric plasma treatment time was longer and the power was higher in Example 2;

[0104] Thermal stability: The thermal stability of all the examples is higher than that of the comparative example. This is because the preparation temperature of the epoxy resin prepolymer in the examples is higher, forming a tighter network structure. Among them, the thermal stability of Example 2 is slightly higher than that of Example 1 because the temperature used in the preparation of the heterocyclic aramid solution and the preparation of the epoxy resin prepolymer is higher than that of Example 1.

[0105] Flame retardancy: The flame retardancy of all the examples is better than that of the comparative example. The flame retardancy of Examples 1 and 2 is very close, and both are higher than that of Comparative Examples 1 and 2. This is because the examples use a step-by-step impregnation method of heterocyclic aramid (HA) and epoxy resin prepolymer on the basis of non-thermal atmospheric plasma treatment, and the impregnation is performed in this order, thereby improving the flame retardancy of the aramid composite paper;

[0106] Tensile strength: The tensile strength of the embodiments is higher than that of the comparative examples, indicating that the treatment method in the embodiments can more effectively enhance the mechanical properties of the aramid composite paper. The tensile strength of Example 2 is higher than that of Example 1 because the impregnation time is longer and the curing pressure is higher.

[0107] Other mechanical properties (bending strength): The bending strength of the embodiments is higher than that of the comparative examples, which further proves the effectiveness of the surface treatment method in the embodiments, and the bending strength of Example 2 is higher than that of Example 1, which is consistent with the result of tensile strength.

[0108] The advantages are: the present invention helps to improve the comprehensive performance of aramid composite paper by adopting non-thermal atmospheric plasma treatment combined with a step-by-step impregnation process of heterocyclic aramid (HA) and epoxy resin prepolymer, wherein the non-thermal atmospheric plasma treatment can effectively enhance the activity of the fiber surface, thereby improving the interfacial adhesion between the fibers. At the same time, the preparation of the heterocyclic aramid solution and the preparation process of the epoxy resin prepolymer after optimizing the conditions can further improve the bonding force between the fiber and the resin, making the paper structure denser. The higher prepolymer reaction temperature and extended impregnation time in the preparation process of the epoxy resin prepolymer help to form a tighter network structure between the aramid composite paper and the epoxy resin, thereby improving the thermal stability of the composite paper. In terms of flame retardant properties, the present invention can give full play to the synergistic effect of heterocyclic aramid and epoxy resin through a step-by-step impregnation process to improve the flame retardant properties of the aramid composite paper. Therefore, the treatment method of the present invention can effectively improve the interfacial adhesion, thermal stability, flame retardancy and mechanical properties of the aramid composite paper.

[0109] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating epoxy-impregnated aramid composite paper based on non-thermal atmospheric plasma, characterized in that: The following steps are involved: Step 1: Material preparation: aramid composite paper, heterocyclic aramid solution, epoxy resin prepolymer, curing agent and solvent; Step 2, pretreatment stage: After cleaning the surface of the aramid composite paper, non-thermal atmospheric plasma treatment is performed; Step 3, impregnation of heterocyclic aramid: preparing a heterocyclic aramid solution, placing the aramid composite paper into the heterocyclic aramid solution, performing a first impregnation, and drying and curing after the impregnation; Step 4: Epoxy resin impregnation: preparing epoxy resin prepolymer, placing the aramid composite paper into the epoxy resin prepolymer, and performing a second impregnation, and removing excess resin after impregnation; Step 5, post-processing: the aramid composite paper with excess resin removed is subjected to curing, demoulding and finishing treatment; Step 6: Performance testing: Perform performance testing on the aramid composite paper after fine finishing.

2. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: In the surface cleaning process of step 2, the aramid composite paper is placed in ethanol for ultrasonic cleaning for 30-45 minutes, and after being taken out, it is then cleaned with deionized water for 5-8 times, and the aramid composite paper is blown dry with nitrogen.

3. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: The non-thermal atmospheric plasma treatment process in step 2: S2.1, placing the dried aramid composite paper into a non-thermal atmospheric plasma device for plasma treatment; S2.

2. Set the plasma treatment time of the non-thermal atmospheric plasma equipment to 10-15 minutes and the power to 150-200W.

4. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: The preparation process of the heterocyclic aramid solution in step 3 is as follows: S3.

1. Prepare the reagents: terephthaloyl chloride, p-phenylenediamine, 5(6)-amino-2-(4-aminophenyl)benzimidazole, N,N-dimethylacetamide, dimethyl sulfoxide and lithium chloride; S3.2, polymerization process: add lithium chloride to a reactor, set the reactor temperature to 0-3°C, add p-phenylenediamine and 5(6)-amino-2-(4-aminophenyl)benzimidazole, stir for 10-15 minutes until completely dissolved, first add 4 / 5 of terephthaloyl chloride for the first stage reaction, the reaction time is 45-50 minutes, then raise the reactor temperature to 20-30°C, add 1 / 5 of terephthaloyl chloride for the second stage reaction, the reaction time is 25-30 minutes, after the reaction is complete, a heterocyclic aramid solution is obtained.

5. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: In the step 3, the aramid composite paper is immersed in the heterocyclic aramid solution for 55-65 minutes.

6. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: The drying and curing process in step 3 is as follows: the impregnated aramid composite paper is taken out, initially dried with nitrogen, dried in an oven at 65-70°C for 8-12 minutes, and then subjected to a pressure of 1.5-2MPa at 155-160°C for hot pressing curing for 1.5-1.8 hours.

7. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: The preparation process of the epoxy resin prepolymer in step 4: S4.

1. Select reagents: select bisphenol A epoxy resin and hydrogen-containing silane as the base reagents; S4.

2. Equipment selection: reactor; S4.3, epoxidation reaction conditions: set the reactor temperature to 80-180°C, and the reactor reaction time to 35-55 minutes; S4.4, condensation reaction: add bisphenol A epoxy resin and hydrogen-containing silane into a reaction kettle to react to form a linear molecular structure, and finally obtain an epoxy resin prepolymer.

8. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: In the step 4, the aramid composite paper is immersed in the epoxy resin prepolymer for a second time, and the immersion time is 1-1.2 hours.

9. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: In the fourth step, the aramid composite paper is used to remove excess resin: the impregnated aramid composite paper is placed between two parallel flat plates, and a pressure of 100-150 Pa is applied to the flat plates by an air pressure device to squeeze out excess epoxy resin.

10. The method for treating epoxy impregnated aramid composite paper based on non-thermal atmospheric plasma according to claim 1, characterized in that: The curing conditions in step 5 are: setting the curing temperature to 160-165° C., setting the curing pressure to 2-2.5 MPa, and setting the curing time to 1.0-1.3 h.

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