A method for preparing polyarylene ether nitrile films

Abstract

This invention provides a method for preparing a polyarylene ether nitrile film, comprising the following steps: forming a wet film on a substrate by forming a mixture containing polyarylene ether nitrile, a catalyst, and a solvent, and then drying it at 80–200°C to obtain an initial film; wherein the catalyst comprises a halide; and subjecting the initial film to uniaxial stretching treatment at 260–280°C to obtain the polyarylene ether nitrile film. This invention can improve the high-temperature resistance and mechanical strength of the polyarylene ether nitrile film.

Description

Technical Field

[0001] This invention relates to the field of polymer membrane technology, and specifically to a method for preparing a polyarylene ether nitrile film. Background Technology

[0002] With the rapid development of science and technology, the demand for special high-performance films in high-tech fields such as aviation, aerospace, machinery, electronics, and new energy is steadily increasing. Currently, polyimide films, known as "golden films," are widely used in these fields. However, polyimide films have defects such as poor resistance to damp heat and complex preparation processes, which limit their application. Therefore, the development of new high-performance engineering films is of great significance.

[0003] Polyarylene ether polymers, as representatives of heat-resistant and thermoplastic engineering materials, have gradually attracted widespread attention. Among them, polyarylene ether nitrile (PEN) is a new type of material. Due to its good high-temperature resistance, damp-heat resistance, and corrosion resistance, it has been widely used in aerospace, mechanical electronics, chemical petroleum, and automotive manufacturing. The glass transition temperature of traditional PEN films is in the range of 148℃-260℃. To optimize the high-temperature resistance of polymer films, current methods mainly focus on the design and synthesis of PEN molecular structures. One or more crosslinkable groups are introduced into high molecular weight polymers, and then combined with solid-state chemical reactions to form a crosslinked network structure, thereby restricting molecular weight movement. This method can improve the glass transition temperature and thermal decomposition temperature of PEN films to a certain extent. However, the subsequent solid-state chemical reaction conditions are harsh, with high temperatures and long processing times, making it impossible to quantitatively control the degree of crosslinking. In particular, the resulting PEN films are often brittle and have poor mechanical properties, which is detrimental to their use.

[0004] For example, CN113388137A provides a method for preparing high-strength, high-temperature resistant polyarylene ether nitrile films by melt blending polyarylene ether nitrile with biphenyl-type bis(phthalonitrile) to obtain the polyarylene ether nitrile film. However, the polyarylene ether nitrile film obtained by this method has poor mechanical properties. For example, patent document CN110628014A provides a method for preparing cross-linked polyarylene ether nitrile high-temperature resistant dielectric films by introducing an amino group of active hydrogen into phthalonitrile-terminated polyarylene ether nitrile. This synthesis process is relatively cumbersome and complex, and the product has low temperature resistance.

[0005] Therefore, how to provide a method for preparing polyarylene ether nitrile films and improve their high-temperature resistance and mechanical strength is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention provides a method for preparing polyarylene ether nitrile films, which at least solves the problems existing in the prior art where polyarylene ether nitrile films cannot simultaneously possess high temperature resistance and high mechanical strength.

[0007] In one aspect, the present invention provides a method for preparing a polyarylene ether nitrile film, comprising the following steps: forming a wet film from a mixture containing polyarylene ether nitrile, a catalyst, and a solvent, and then drying it at 80°C to 200°C to obtain an initial film; wherein the catalyst includes a halide; and subjecting the initial film to uniaxial stretching treatment at 260°C to 320°C to obtain a polyarylene ether nitrile film.

[0008] According to one embodiment of the present invention, the mass ratio of catalyst to polyarylether nitrile is (0.1-3):100; and / or, the mass-volume ratio of polyarylether nitrile to solvent is (1g-3g):40mL.

[0009] According to one embodiment of the present invention, the chemical structural formula of polyarylether nitrile is shown in Formula 1:

[0010]

[0011] Ar1 and Ar2 each independently include a divalent substituent containing at least one benzene ring.

[0012] According to one embodiment of the present invention, Ar1 and Ar2 each independently include at least one of the substituents shown in Formulas 2, 3, 4, and 5:

[0013]

[0014] According to one embodiment of the present invention, the catalyst includes at least one selected from aluminum chloride, ferric chloride, beryllium chloride, tin tetrachloride, chromium trichloride, bismuth trichloride, lanthanum chloride, boron trifluoride, and zinc chloride.

[0015] According to one embodiment of the present invention, the solvent includes at least one selected from diphenyl sulfone, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylformamide, or N,N-dimethylacetamide.

[0016] According to one embodiment of the present invention, the stretching process includes: suspending the initial membrane longitudinally, fixing its upper end, placing a weight at its lower end, stretching it by the gravity of the weight, and maintaining the stretching time for 1 hour to 4 hours.

[0017] According to one embodiment of the present invention, a wet film is formed by casting; and / or the drying time is 8h to 48h.

[0018] According to one embodiment of the present invention, the stretching ratio x of the unidirectional stretching treatment satisfies: 10% ≤ x ≤ 100%, where x = (L1 - L0) / L0, L0 is the length of the film before the stretching treatment, and L1 is the length of the film after the stretching treatment.

[0019] According to one embodiment of the present invention, the above preparation method further includes: obtaining a membrane precursor after the uniaxial stretching treatment; and cooling and quenching the membrane precursor with water at 5°C to 20°C to obtain the polyarylene ether nitrile film.

[0020] The implementation of this invention has at least the following beneficial effects:

[0021] The method for preparing polyarylene ether nitrile film provided by the present invention uses polyarylene ether nitrile, catalyst and solvent as raw materials to form a wet film, and performs low-temperature molding of the wet film at 80℃~200℃, followed by high-temperature unidirectional hot stretching treatment at 260℃~280℃. This method can improve the high-temperature resistance and mechanical properties of the polyarylene ether nitrile film. Specifically, the glass transition temperature of the polyarylene ether nitrile film can reach above 275℃, the tensile strength can reach above 178MPa, and the tensile modulus can reach above 1.8GPa.

[0022] Furthermore, the preparation method of polyarylether nitrile film provided by the present invention has the advantages of simple preparation process and easy operation, which is conducive to industrial production and application. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of a method for preparing a polyarylether nitrile film according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of a unidirectional stretching process according to an embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] This invention provides a method for preparing a polyarylene ether nitrile film, comprising the following steps: forming a wet film on a substrate by forming a mixture containing polyarylene ether nitrile, a catalyst, and a solvent, and then drying it at 80°C to 200°C to obtain an initial film; wherein the catalyst includes a halide; and subjecting the initial film to uniaxial stretching treatment at 260°C to 280°C to obtain a polyarylene ether nitrile film.

[0027] like Figure 1As shown, the method for preparing polyarylene ether nitrile films provided by this invention involves forming a wet film using polyarylene ether nitrile, a catalyst, and a solvent as raw materials. Low-temperature molding is used to evaporate the solvent in the wet film, and after drying, an initial film is obtained. This low-temperature molding method helps ensure the structural integrity of the initial film, with the catalyst remaining in the film as a reinforcing phase. In the uniaxial thermal stretching process, a thermal crosslinking reaction is promoted between the cyano groups on the polyarylene ether nitrile under high temperature conditions, forming a dense network structure. This network structure can improve the structural stability and high-temperature resistance of the polyarylene ether nitrile film. Simultaneously, in the uniaxial thermal stretching process, directional stretching causes molecular orientation and rearrangement within the polyarylene ether nitrile, further improving the mechanical properties of the polyarylene ether nitrile film. Furthermore, the catalyst in this system can accelerate the rate of crosslinking reaction of the cyano groups, and the catalyst, as a reinforcing phase, remains in the polyarylene ether nitrile film, further enhancing its mechanical properties.

[0028] In some embodiments, the mass ratio of the catalyst to the polyarylether nitrile is (0.1 to 3):100, for example, a range consisting of 0.1:100, 0.3:100, 0.5:100, 1:100, 2:100, 3:100, or any two of these.

[0029] In some embodiments, the mass-to-volume ratio of polyarylene ether nitrile to solvent is (1g to 3g): 20mL, for example, a range consisting of 1g: 20mL, 1.5g: 20mL, 2g, 20mL, 2.5g, 20mL, 3g: 20mL, or any two of these. The mass-to-volume ratio of polyarylene ether nitrile to solvent is the ratio of the mass of the polyarylene ether nitrile to the volume of the solvent.

[0030] Generally, the macromolecular backbone of polyarylether nitrile contains a large number of aromatic rings, and the side chains are cyano groups. Crosslinking reactions can occur between these cyano groups. The polyarylether nitrile of this invention is a crosslinkable polyarylether nitrile, in which both the molecular backbone and side chains (terminal groups) contain cyano groups, which can serve as sites for crosslinking reactions. In some embodiments, the chemical structural formula of the polyarylether nitrile is shown in Formula 1:

[0031]

[0032] Ar1 and Ar2 each independently include a divalent substituent containing at least one benzene ring; Ar1 ​​and Ar2 may be the same or different.

[0033] In some embodiments, Ar1 and Ar2 are each independently selected from at least one of the divalent substituents shown in Formulas 2, 3, 4, and 5, whether substituted or unsubstituted:

[0034]

[0035] Ar1 and Ar2 can be the same or different.

[0036] Taking Ar1 as the unsubstituted divalent substituent shown in Formula 4 and Ar2 as the unsubstituted substituent shown in Formula 4 as an example, the structure of Formula 1 is shown in Formula 1-1:

[0037]

[0038] Taking Ar1 as the unsubstituted divalent substituent shown in Formula 2 and Ar2 as the unsubstituted substituent shown in Formula 2 as an example, the structure of Formula 1 is shown in Formula 1-2:

[0039]

[0040] Taking Ar1 as the unsubstituted divalent substituent shown in Formula 2 and Ar2 as the unsubstituted substituent shown in Formula 3 as an example, the structure of Formula 1 is shown in Formulas 1-3:

[0041]

[0042] Specifically, Ar1 and Ar2 are each independently derived from a diphenol, which includes at least one of the substituted or unsubstituted diphenols represented by formulas 2, 3, 4, and 5:

[0043]

[0044] In this invention, the catalyst includes halides, i.e., salts containing halogen elements, wherein the halides include metal halides and / or boron halides. For example, in some preferred embodiments, the polyarylene ether nitrile membrane includes a polyarylene ether nitrile matrix and halides present in the polyarylene ether nitrile matrix, wherein the halides include metal halides and / or boron halides. Introducing the halides is beneficial for further enhancing the mechanical strength and other properties of the polyarylene ether nitrile membrane.

[0045] The metal halide may include at least one of aluminum, iron, tin, chromium, bismuth, lanthanum, and zinc. Specifically, the halide may include chlorides and / or fluorides, i.e., at least one of metal chlorides, metal fluorides, and boron fluorides. In some preferred embodiments, the halide includes at least one of aluminum chloride (AlCl3), ferric chloride (FeCl3), beryllium chloride (BeCl2), tin tetrachloride (SnCl4), chromium trichloride (CrCl3), bismuth trichloride (BiCl3), lanthanum chloride (LaCl3), boron trifluoride (BF3), and zinc chloride (ZnCl2).

[0046] Specifically, the solvents mentioned above include organic solvents, such as sulfone solvents, pyrrolidone solvents, and amide solvents. Amide solvents include, for example, formamide solvents and / or acetamide solvents, and polar solvents are generally preferred. In some embodiments, the solvent includes at least one of diphenyl sulfone, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylformamide, or N,N-dimethylacetamide, preferably N-methylpyrrolidone.

[0047] In this invention, the process of forming the mixture includes: dissolving polyarylene ether nitrile and catalyst in a solvent, mixing them thoroughly, and obtaining the mixture.

[0048] In this invention, a casting method is generally used to form a wet film from the above-mentioned mixture. Specifically, a wet film can be formed on a substrate, dried, and then the resulting initial film can be removed from the substrate and subjected to uniaxial stretching. The substrate used should have a clean and flat surface to facilitate the formation of a wet film on the surface by the flowability of the mixture during the casting process. The substrate may include, for example, a glass plate.

[0049] In the above preparation process, drying the wet film at 80℃ to 200℃ removes the solvent, allowing the wet film to dry and solidify, thus obtaining the initial film. Exemplarily, the drying temperature of this wet film process is within the range of 80℃, 90℃, 100℃, 120℃, 140℃, 150℃, 180℃, 200℃, or any combination thereof. Drying the wet film at these lower temperatures not only removes the solvent but also does not damage the film structure, resulting in a film with a complete structure and strong overall performance. Furthermore, the drying time of the wet film at 80℃ to 200℃ is generally 8h to 48h, for example, 8h, 10h, 15h, 24h, 36h, 48h, or any combination thereof. In practice, the wet film can be dried in a drying device such as an oven.

[0050] The thickness of the initial film can be from 30 μm to 70 μm, for example, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 50 μm, 70 μm, or any combination thereof. Specifically, the initial film can be square, and more particularly rectangular, for example, a rectangle with a width of 10 mm and a length of 100 mm, which facilitates subsequent uniaxial stretching. In practice, the initial film can be cut into the above shape.

[0051] Specifically, the temperature during the uniaxial stretching process is 260℃~320℃, for example, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃, 300℃, 305℃, 310℃, 315℃, 320℃ or any combination thereof. During this high-temperature uniaxial stretching process, the cyano groups on the polyarylene ether nitrile backbone in the initial film undergo a full thermal crosslinking reaction with the cyano groups on the end groups, forming a dense network structure through the thermal crosslinking reaction.

[0052] In general, during the preparation of polyarylene ether nitrile membranes, the cyano groups on the main chain and side chains of polyarylene ether nitrile undergo a cross-linking reaction. This usually requires harsh conditions such as high temperature and long duration for cross-linking and curing to form the membrane product. However, the high temperature and long duration of curing can lead to the decomposition of small molecules, which has a significant impact on the mechanical strength and other properties of the prepared polyarylene ether nitrile membrane. This often results in defects such as brittleness in the prepared polyarylene ether nitrile membrane, making it impossible to obtain a polyarylene ether nitrile membrane that combines high strength, high modulus, and high temperature resistance.

[0053] Specifically, the uniaxial stretching process may include: suspending the initial membrane longitudinally with its upper end fixed, placing a weight at its lower end, and stretching it through the gravity of the weight. That is, under the influence of gravity, the initial membrane is stretched longitudinally in a directional manner, causing a change in its longitudinal length, thereby achieving uniaxial stretching of the initial membrane to obtain a polyarylether nitrile membrane. Here, longitudinal refers to the direction of gravity, and the weight of the weight can be 100g to 300g.

[0054] Furthermore, the unidirectional stretching treatment time can generally be 1 hour to 4 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, or any combination thereof. In specific implementation, the stretching ratio can be set as needed, and stretching can be maintained for 1 hour to 4 hours at the set stretching ratio. This stretching ratio is 10% ≤ x ≤ 100%, preferably 10% ≤ x ≤ 60%, where x = (L1 - L0) / L0, L0 is the length of the film before stretching treatment (i.e., the initial film length), L1 refers to the length of the film after stretching treatment (i.e., the length of the polyarylene ether nitrile film), and x is, for example, a range of 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or any combination thereof. Specifically, the film stretching ratio can be controlled by adjusting the gravity of the weights and their distance from the bottom of the oven, for example... Figure 2 As shown, the initial membrane has a width of 1 cm and a length of 10 cm, with a stretch ratio of 1.5. The membrane can then be stretched to 15 cm (i.e., stretched by 5 cm) by the gravity of a weight. The weight is then fixed in place and maintained in this state for 1 to 4 hours to obtain a polyarylene ether nitrile membrane. Furthermore, as... Figure 1As shown, the initial membrane can also be stretched to 10cm, 15cm, 20cm, etc. The specific length can be set according to the needs during implementation. After stretching, the width of the membrane generally remains basically unchanged.

[0055] In practice, the uniaxial stretching process described above can be carried out in an oven at a temperature of 260°C to 320°C. The oven has a first clamp and a second clamp. One end of the first clamp is fixed to the upper part of the oven, and the other end is used to fix the upper part of the initial film. One end of the second clamp is used to fix the lower part of the initial film, and the other end is used to suspend a weight, thereby fixing the upper part of the initial film and suspending a weight at the lower part, and performing uniaxial stretching under the gravity of the weight.

[0056] In some embodiments, the method further includes: obtaining a membrane precursor by uniaxial stretching; and cooling and quenching the membrane precursor with water at a temperature of 5°C to 20°C to obtain a polyaryletheronitrile film. The cooling and quenching process includes placing the membrane precursor in cold water for cooling and quenching, wherein the temperature of the cold water is 5°C to 20°C, for example, 5°C, 10°C, 15°C, 20°C, or any combination thereof.

[0057] In some embodiments, the thickness of the polyaryletheronitrile film is 40 μm to 70 μm, for example, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, or any combination thereof.

[0058] In this invention, the polyarylene ether nitrile film prepared by the above preparation method has excellent high temperature resistance and mechanical properties. Studies have shown that its glass transition temperature is above 275℃, its tensile strength is above 178MPa, and its tensile modulus is above 1.8GPa. It can be applied to film capacitors, insulating materials for electronic appliances, flexible copper clad laminates and other fields.

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0060] In the following examples, the polyarylene ether nitriles used are of formula 1-1 and formula 1-2, respectively:

[0061]

[0062] In the following embodiments, the uniaxial stretching treatment is carried out in an oven, and the process is as follows: The oven has a first clamp and a second clamp. One end of the first clamp is fixed to the upper end of the oven interior, and the other end is fixed to the upper end of the initial film. One end of the second clamp is fixed to the lower end of the initial film, and the other end suspends a weight. Stretching is performed under the gravity of the weight. The initial film is cut to a width of 1 cm and a length of 10 cm before being placed in the oven for uniaxial stretching treatment. During the uniaxial stretching treatment, the oven temperature is controlled at T, the weight of the weight is m, the distance between the weight and the bottom surface of the oven interior is L, the stretching ratio is x, and the holding time (i.e., the uniaxial stretching treatment time) at temperature T1 and stretching ratio x is t.

[0063] Example 1

[0064] Mix 1-11.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0065] The mixture is used to form a wet film through a casting process;

[0066] The wet film was dried at 160℃ for 10 hours to obtain the initial film.

[0067] The initial membrane was subjected to uniaxial stretching at 280℃ (i.e., T1 = 280℃) to obtain the membrane precursor; wherein, the weight of the weight m = 200g, the distance between the weight and the bottom of the oven L = 30mm, the stretching ratio x = 30%, and the uniaxial stretching treatment time t = 2h.

[0068] The membrane precursor was cooled and quenched in cold water at about 15°C to obtain a polyarylether nitrile membrane.

[0069] Example 2

[0070] Mix 1-11.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0071] The mixture is used to form a wet film through a casting process;

[0072] The wet film was dried at 160℃ for 10 hours to obtain the initial film.

[0073] The initial membrane was subjected to uniaxial stretching at 300℃ (i.e., T1 = 300℃) to obtain the membrane precursor; wherein, the weight of the weight m = 200g, the distance between the weight and the bottom of the oven L = 30mm, the stretching ratio x = 30%, and the uniaxial stretching treatment time t = 2h;

[0074] The membrane precursor was cooled and quenched in cold water at about 15°C to obtain a polyarylether nitrile membrane.

[0075] Example 3

[0076] Mix 1-11.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0077] The mixture is formed into a wet film using a casting method;

[0078] The wet film was dried at 160℃ for 10 hours to obtain the initial film.

[0079] The initial membrane was subjected to uniaxial stretching at 320℃ (i.e., T1 = 320℃) to obtain the membrane precursor; wherein, the weight of the weight m = 200g, the distance between the weight and the bottom of the oven L = 30mm, the stretching ratio x = 30%, and the uniaxial stretching treatment time t = 2h;

[0080] The membrane precursor was cooled and quenched in cold water at about 15°C to obtain a polyarylether nitrile membrane.

[0081] Example 4

[0082] Mix 1-11.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0083] The mixture is used to form a wet film through a casting process;

[0084] The wet film was dried at 160℃ for 10 hours to obtain the initial film.

[0085] The initial membrane was subjected to uniaxial stretching at 300℃ (i.e., T1 = 300℃) to obtain the membrane precursor; wherein, the weight of the weight m = 200g, the distance between the weight and the bottom of the oven L = 20mm, the stretching ratio x = 20%, and the uniaxial stretching treatment time t = 2h.

[0086] The membrane precursor was cooled and quenched in cold water at about 15°C to obtain a polyarylether nitrile membrane.

[0087] Example 5

[0088] Mix 1-11.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0089] The mixture is used to form a wet film through a casting process;

[0090] The wet film was dried at 160℃ for 10 hours to obtain the initial film.

[0091] The initial membrane was subjected to uniaxial stretching at 300℃ (i.e., T1 = 300℃) to obtain the membrane precursor; wherein, the weight of the weight m = 200g, the distance between the weight and the bottom of the oven L = 50mm, the stretching ratio x = 50%, and the uniaxial stretching treatment time t = 2h.

[0092] The membrane precursor was cooled and quenched in cold water at about 15°C to obtain a polyarylether nitrile membrane.

[0093] Example 6

[0094] Mix 1-21.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0095] The mixture is used to form a wet film through a casting process;

[0096] The wet film was dried at 160℃ for 10 hours to obtain the initial film.

[0097] The initial membrane was subjected to uniaxial stretching at 300℃ (i.e., T1 = 300℃) to obtain the membrane precursor; wherein, the weight of the weight m = 200g, the distance between the weight and the bottom of the oven L = 30mm, the stretching ratio x = 30%, and the uniaxial stretching treatment time t = 2h;

[0098] The membrane precursor was cooled and quenched in cold water at about 15°C to obtain a polyarylether nitrile membrane.

[0099] Example 7

[0100] Mix 1-21.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0101] The mixture is used to form a wet film through a casting process;

[0102] The wet film was dried at 160℃ for 10 hours to obtain the initial film.

[0103] The initial membrane was subjected to uniaxial stretching at 320℃ (i.e., T1 = 320℃) to obtain the membrane precursor; wherein, the weight of the weight m = 200g, the distance between the weight and the bottom of the oven L = 30mm, the stretching ratio x = 30%, and the uniaxial stretching treatment time t = 2h;

[0104] The membrane precursor was cooled and quenched in cold water at about 15°C to obtain a polyarylether nitrile membrane.

[0105] Comparative Example 1

[0106] Mix 1-11.5g of polyarylene ether nitrile, 0.005g of zinc chloride, and 20mL of N-methylpyrrolidone to obtain a mixture;

[0107] The mixture is used to form a wet film through a casting process;

[0108] The wet film was dried at 160℃ for 10 hours to obtain the control sample film.

[0109] Table 1 summarizes the polyarylene ether nitrile, uniaxial stretching temperature T1, stretching ratio x, and the thickness, glass transition temperature, tensile strength, and tensile modulus of the polyarylene ether nitrile film of each embodiment and the comparative sample film of the comparative example used in each embodiment and the comparative example.

[0110] Table 1

[0111]

[0112] As shown in Table 1, the polyarylene ether nitrile film prepared by the method provided by the present invention has a glass transition temperature of 275°C or higher, a tensile strength of 178 MPa or higher, and a tensile modulus of 1.8 GPa or higher. The tensile modulus of the polyarylene ether nitrile film in Example 5 is as high as 3.3 GPa, which is much higher than that of the comparative example.

[0113] In summary, the method for preparing polyarylene ether nitrile films provided by the present invention can obtain polyarylene ether nitrile films that have both high temperature resistance and high mechanical strength.

[0114] The preferred embodiments and experimental verifications of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a polyarylene ether nitrile film, characterized in that, Includes the following steps: A wet film is formed by forming a mixture containing polyarylene ether nitrile, catalyst, and solvent, and then dried at 80°C to 200°C to obtain an initial film; wherein the catalyst includes a halide. The initial film was subjected to uniaxial stretching at 260℃~320℃ to obtain a polyarylene ether nitrile film. The unidirectional stretching process includes: suspending the initial membrane longitudinally, fixing its upper end, placing a weight at its lower end, and stretching it by the gravity of the weight, maintaining the stretching time for 1 hour to 4 hours; The mass ratio of the catalyst to the polyarylene ether nitrile is (0.1-3):100; the catalyst includes at least one of aluminum chloride, ferric chloride, beryllium chloride, tin tetrachloride, chromium trichloride, bismuth trichloride, lanthanum chloride, boron trifluoride, and zinc chloride; the mass-volume ratio of the polyarylene ether nitrile to the solvent is (1g-3g):40mL; and the drying time is 10h-48h.

2. The preparation method according to claim 1, characterized in that, The chemical structural formula of the polyarylene ether nitrile is shown in Formula 1: Formula 1 Ar1 and Ar2 each independently include a divalent substituent containing at least one benzene ring.

3. The preparation method according to claim 2, characterized in that, Ar1 and Ar2 each independently include at least one of the substituents shown in Formulas 2, 3, 4, and 5: Formula 2, Formula 3, Formula 4, Formula 5.

4. The preparation method according to any one of claims 1-3, characterized in that, The solvent includes at least one of diphenyl sulfone, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N,N-dimethylformamide, or N,N-dimethylacetamide.

5. The preparation method according to claim 1, characterized in that, A wet film is formed using a casting method.

6. The preparation method according to claim 1, characterized in that, The stretching ratio x of the unidirectional stretching treatment satisfies: 10%≤x≤100%, where x=(L1-L0) / L0, L0 is the length of the film before stretching treatment, and L1 is the length of the film after stretching treatment.

7. The preparation method according to claim 1, characterized in that, Also includes: After the uniaxial stretching treatment, the membrane precursor is obtained; The membrane precursor was cooled and quenched with water at 5℃~20℃ to obtain the polyarylether nitrile film.

Images