A polyarylate nanofiber and its preparation method

Abstract

The present invention provides a polyarylate nanofiber and a preparation method thereof. The preparation method includes the following steps: First, 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA) are subjected to an acetylation reaction to obtain acetylated HBA and acetylated HNA, and then copolymerized with 4-hydroxybutyric acid (GHB) to obtain a HBA / GHB / HNA copolyarylate granule B. The granule B is blended and spun with a HBA / HNA copolyarylate granule A obtained by copolymerizing traditional acetylated HBA and acetylated HNA. Then, the obtained blended polyarylate fiber is placed in an organic solvent containing a strong base for chemical etching and deprotonation, and the polyarylate nanofiber suspension is disassembled "from top to bottom". Finally, suction filtration and drying are carried out to obtain the polyarylate nanofiber. In the present invention, the blended polyarylate fiber containing an aliphatic chain is etched and deprotonated by a strong base to disassemble the polyarylate nanofiber, and the introduction of a certain amount of -CH2- structure into the main chain helps the disassembly and preparation of the nanofiber, and polyarylate nanofibers with uniform diameter, length and controllable aspect ratio are obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanofibers and relates to a method for preparing polyarylate nanofibers. Background Art

[0002] Liquid Crystal Polyarylate (LCP) is a class of high-performance materials with liquid crystal properties. Its excellent mechanical properties, heat resistance, chemical resistance, and dimensional stability make it widely used in various fields. The internal molecular chains of LCP have a high degree of regularity. After heating, it can form a liquid crystal phase, and the molecular chains can be arranged orderly during the flow process, thus forming a highly oriented structure. Therefore, when LCP is melt-spun at high speed, at a high shear rate at the spinneret, the LCP molecular chains are arranged orderly along the spinning direction with the melt and flow at high speed. After spinning into LCP fibers, the molecular chains are arranged orderly along the fiber axis, forming anisotropy, which is shear-induced orientation. Therefore, the binding force along the fiber axis is dominated by chemical bonds in the molecular chains, so the binding force is strong, while along the fiber radial direction, the binding force is dominated by weaker binding forces such as intermolecular forces and van der Waals forces, resulting in a large difference in the binding force in all directions inside the LCP fibers. Inspired by the preparation of aramid nanofibers by etching aramid nanofibers, dimethyl sulfoxide (DMSO)-potassium hydroxide (KOH) removes the proton H in -CONH- in the molecular chain with KOH, making the N atom negatively charged. Through negative charge repulsion, the distance between molecular chains is increased to achieve the purpose of disassembling along the fiber axis. At the same time, this system will also etch the amorphous region part in the fiber, destroying the weak binding force along the fiber radial direction, such as van der Waals force, hydrogen bond, π-π interaction, etc., and retaining the crystalline region part and the strong chemical bond force along the fiber axis. Therefore, aramid fibers at the nanoscale are obtained "from top to bottom". Therefore, we use this etching method to treat polyarylate fibers in order to obtain polyarylate nanofibers. Summary of the Invention

[0003] The purpose of the present invention is to prepare a blend LCP nanofiber with a small and uniform diameter, a length-to-diameter ratio that can be numerically controlled by a function, and capable of large-scale continuous production.

[0004] In order to achieve the above purpose, the present invention provides a preparation scheme for blend LCP nanofibers:

[0005] (1) Copolymerize acetylated 4-hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA), and 4-hydroxybutyric acid (GHB) to obtain HBA / GHB / HNA copolymer LCP (granule B); copolymerize acetylated HBA and HNA to obtain HBA / HNA copolymer LCP (granule A);

[0006] (2) Melt-spin the pellet A and pellet B in step (1), melt them respectively through single-screw extruder A and single-screw extruder B, and convey them through the supporting function numerical control metering pump A and metering pump B. Then, convey the melt A and melt B to the static mixer at a certain mass ratio, and extrude them through the spinneret after sufficient mixing to obtain the blended LCP fiber;

[0007] (3) Place the fiber obtained by spinning in step (2) into dimethyl sulfoxide (DMSO), add solid potassium hydroxide (KOH), and stir for a certain time at a certain temperature to obtain the blended LCP nanofiber suspension;

[0008] (4) Filter the suspension obtained in step (3), wash it with deionized water, and then dry it in an oven to finally obtain the blended LCP nanofiber.

[0009] Preferably, the mass ratio of each component in pellet B in step (1) is acetylated HBA:acetylated HNA:GHB = 70:30:(1 - 5), and more preferably acetylated HBA:acetylated HNA:GHB = 70:30:5; the mass ratio of each component in pellet A is acetylated HBA:acetylated HNA = 7:3.

[0010] Preferably, the rotation speed N of metering pump A in step (2) A and the time t satisfy the functional relationship N A =sin[π(t - 15) / 30]+9+2k, the rotation speed N of metering pump B B and the time t satisfy the functional relationship N B =N - N A =-sin[π(t - 15) / 30]+11–2k, t is the number of seconds of the real-time time and is constantly changing, and the periods of both functions are 60s. The value of k determines the rotation speed range and the k values of both functions are the same, with a value range of 1 - 3.

[0011] Preferably, the mass ratio of the two pellets is directly controlled and constantly changed by N B and N A , and the calculation formula is: the mass ratio of pellet A or B=(N A or N B / N)×100%. The value of k is 1 - 3, corresponding to the total ranges of N A and N B being 10 - 16 rpm and 10 - 4 rpm respectively, and corresponding to the mass ratios of pellet A and pellet B being 50% - 80% and 50% - 20% respectively. And the sum of the rotation speeds at the same time is the total rotation speed N, which is constantly 20 rpm, that is, N = 20 rpm = N A +N B , corresponding to the sum of the mass ratios of the two pellets being constantly 100%.

[0012] Preferably, in step (2), the temperatures of the four zones of the two single-screw extruders for melt blending and spinning are 250 °C, 280 °C, 300 °C, and 320 °C respectively, the screw speeds are all 90 rpm, and the shear rate at the spinneret is 2000 s -1 , the winding speed of the winder is 300 rpm, and the reciprocating shaft frequency is 200 Hz.

[0013] Preferably, in step (3), the correspondence between the fiber and the DMSO-KOH etching system is that every 2 g of fiber corresponds to 150 mL of DMSO and 1 g of solid KOH, the temperature is 30 °C, and the stirring time is 10 days.

[0014] Compared with the prior art, the present invention has the following positive and beneficial effects:

[0015] (1) Based on the existing traditional process for preparing HBA / HNA copolymer LCP pellets A by polymerizing acetylated HBA and acetylated HNA, the present invention adds GHB monomer to the polymerization system to obtain a copolymer LCP containing a small amount of -CH2- structure in the main chain, namely HBA / GHB / HNA copolymer LCP pellets B. Among them, the mass ratio of each component in pellets A is acetylated HBA:acetylated HNA = 7:3, and the mass ratio of each component in pellets B is acetylated HBA:acetylated HNA:GHB = 70:30:(1 - 5).

[0016] (2) The present invention blends and melts spins the two kinds of pellets, such as Figure 1 . Different from this, pellets A and pellets B are melted by single-screw extruder A and single-screw extruder B respectively, metered and conveyed by the supporting function numerical control metering pumps A and B, and the melt A and melt B are conveyed to the static mixer at a certain mass ratio, and after being fully mixed, they are extruded through the spinneret to obtain the blended LCP fiber. Among them, the rotation speeds of the two function numerical control metering pumps change continuously with the change of the time in seconds. The rotation speeds N A and N B respectively satisfy the functional relationships N A =sin[π(t - 15) / 30]+9+2k and N B =N - N A =-sin[π(t - 15) / 30]+11–2k, the value of k determines the rotation speed range, and the value range is 1 - 3, and the values in the two functions are the same. t is the number of seconds of the real-time time, and the periods of the two functions are both 60 s. Specifically, see Figure 2 and Table 1. For example, when k = 1, the range of N A is 10 - 12 rpm, and the range of N B is 10 - 8 rpm. Specifically, when the time is 18:31:45, at this time t = 45 s, N A= sin[π(45 - 15) / 30] + 9 + 2 = 11 rpm, N B = 20 - N A = -sin[π(45 - 15) / 30] + 11 - 2 = 9 rpm.

[0017] (3) In the blended LCP fiber obtained by the present invention, the mass ratios of pellet A and pellet B are directly controlled by N A and N B as well as the k value. The calculation formula is: mass ratio of pellet A or B = (N A or N B / N) × 100%. Therefore, the value of k ranges from 1 to 3, corresponding to N A with a total range of 10 - 16 rpm, corresponding to a total range of 50% - 80% for pellet A, corresponding to N B with a total range of 10 - 4 rpm, corresponding to a total range of 50% - 20% for pellet B. And the sum of the rotational speeds at the same time is the total rotational speed N which is constantly 20 rpm, that is, N = 20 rpm = N A + N B , corresponding to the sum of the mass ratios of the two pellets being constantly 100%. For example, when N A = 12 rpm and the total rotational speed N = 20 rpm, then N B = 20 – 12 = 8 rpm. At this time, the mass ratio of pellet A = (12 rpm / 20 rpm) × 100% = 60%, and the mass ratio of pellet B = (8 rpm / 20 rpm) × 100% = 40%. Therefore, as the spinning process progresses, the mass ratios of pellet A and B inside the obtained blended LCP fiber change within a certain range.

[0018] (4) In the blended LCP fiber prepared by the present invention, due to the different structures of the two pellets - pellet B contains a small amount of -CH2- structure while pellet A does not, phase separation is likely to occur inside the fiber obtained by blending and spinning the two pellets. This is beneficial for the DMSO - KOH system to penetrate deep into the fiber and deepen the etching of the amorphous region, and is also beneficial for the deprotonation of the molecular chains by this system to prepare nanofibers.

[0019] (5) The preparation idea of the present invention is to use a method combining deprotonation and etching of the amorphous region to destroy the weak binding force in the radial direction of the blended LCP fiber and retain the strong binding force in the axial direction, and then disassemble the blended LCP nanofiber "from top to bottom". When LCP is melt-spun at high speed, the high speed difference between the spinneret and the flowing melt brings a high shear rate, and the liquid crystal molecular chains of LCP are arranged orderly along the direction of the high-speed flow of the melt, which is shear-induced orientation. After cooling, the LCP molecular chains remain arranged orderly along the fiber axis, and the highly oriented structure induces an increase in crystallinity. Therefore, a highly crystalline anisotropic structure is formed inside the blended LCP fiber. The binding force along the fiber axis is dominated by chemical bonds in the molecular chain, so the binding force is strong, while along the fiber radial direction, the binding force is dominated by relatively weak binding forces such as intermolecular forces and van der Waals forces, resulting in a large difference in the binding force in different directions inside the blended LCP fiber.

[0020] (6) For traditional HBA / HNA copolymerized LCP (granular material A), there is no proton H in the molecular structure. KOH can only etch away the amorphous region in the LCP fiber and cannot achieve the purpose of deprotonation. Therefore, the diameter and length range of the LCP nanofibers prepared by etching are relatively large, and the size is uneven, unstable and uncontrollable. Even only LCP microfibers can be obtained. In the blended LCP fiber (granular material A and granular material B) prepared by the present invention, due to the introduction of the GHB repeating unit, the number of -CH2- structures in the main chain increases. Compared with the ester bond -COO- in HBA / HNA copolymerized LCP, the deprotonation of the DMSO-KOH system is easier, and the obtained nanofibers have a finer diameter and more uniform size. Therefore, it is easier to prepare nanofibers from the blended LCP fiber by the top-down disassembly method. Moreover, the -CH2- structure is more easily etched and broken by the DMSO-KOH system than the ester bond -COO-, so the obtained nanofibers have a shorter length. For the blended LCP fiber obtained by the above melt-spinning method, the components change along the fiber direction - the mass ratio of granular material A and granular material B varies between 50%-80% and 50%-20%. Therefore, when fibers with different mass ratios are etched in the DMSO-KOH system, the lengths of the obtained nanofibers are also different, that is, the aspect ratio is controllable. For example, when the mass ratio of a certain section of the fiber is 70-80% granular material A and 30-20% granular material B, since the proportion of granular material B is small, the deprotonation of the -CH2- structure by the DMSO-KOH system is less, so the obtained nanofibers have a longer length. On the contrary, if the mass ratio of a certain section of the fiber is 50-60% granular material A and 50-40% granular material B, the obtained nanofibers have a shorter length.

[0021] (7) The diameter of the blended LCP nanofibers obtained in this invention can be regulated by the amount of GHB added during copolymerization. When the amount of GHB added is relatively large, the content of -CH2- in the main chain is relatively high. Affected by the electron-withdrawing inductive effect of the carbon-oxygen double bond C=O, the proton H is easily deprotonated by the DMSO-KOH system. Therefore, the obtained nanofibers have a smaller diameter. Thus, the aspect ratio of the nanofibers can be controlled by the mass ratio of the two pellets and the amount of GHB added, and blended LCP nanofibers with different aspect ratios can be obtained. Specific control of the aspect ratio of the nanofibers is given in the following examples. Brief Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the co-spinning of pellet A and pellet B.

[0023] Figure 2 For the metering pump rotation speed N in Examples 1-7 A and N B The image of the functional relationship with time t.

[0024] Figure 3 ① is the acetylation reaction formula of HBA and HNA; ② is the reaction formula for copolymerizing acetylated HBA, acetylated HNA, and GHB to obtain pellet B of HBA / GHB / HNA copolymer LCP and copolymerizing acetylated HBA and acetylated HNA to obtain pellet A of HBA / HNA copolymer LCP.

[0025] Figure 4 It is the field emission scanning electron microscope (FESEM) photograph of the surface and cross-section of the blended LCP fiber.

[0026] Figure 5 It is the FESEM photograph of the blended LCP nanofibers prepared in the control example, Example 3, Example 5, and Example 7. Detailed Description of the Invention

[0027] Common steps of the examples:

[0028] Take two monomers, HBA and HNA, mix them with acetic anhydride, and react at 140°C for 4 h to acetylate the hydroxyl groups of the two monomers, obtaining acetylated HBA and acetylated HNA. Without adding the GHB monomer, only add the obtained acetylated HBA and acetylated HNA to the reaction kettle in a mass ratio of 7:3 for polymerization. Slowly raise the temperature to 300°C, react for 8 h under a nitrogen atmosphere, and keep the temperature at 350°C for 1 h to increase the degree of polymerization and ensure uniform molecular weight. During this process, by-products acetic acid are continuously distilled out through the condenser. After the reaction, pellet A is obtained.

[0029] Another, take acetylated HBA, acetylated HNA, and GHB monomers in a mass ratio of 70:30:(1 - 5), add them together into a reaction kettle for copolymerization, and the polymerization conditions are the same as above. After the reaction, an HBA / GHB / HNA copolymer LCP incorporating GHB repeating units, namely pellet B, is obtained. The specific mass ratio of acetylated HBA, acetylated HNA, and GHB is illustrated in the following respective examples.

[0030] Control Example

[0031] Melt-spin pellet A to obtain HBA / HNA copolymer LCP fibers. When spinning, only single-screw extruder A and metering pump A are used, and at this time N A = N = 20 rpm. This fiber is spun from 100% pellet A and does not contain pellet B, that is, it does not contain the -CH2- structure. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, add 1 g of solid KOH, stir at 30 °C for 10 days to obtain a nanofiber suspension. After suction filtration, washing, and drying, HBA / HNA copolymer LCP nanofibers are obtained, with a diameter range of 1 - 15 μm, a length range of 100 - 500 μm, and an aspect ratio range of 50 - 100.

[0032] Example 1

[0033] Copolymerize acetylated HBA, acetylated HNA, and GHB in a mass ratio of 70:30:1 to obtain pellet B. Mix and melt-spin pellet A and pellet B to obtain blended LCP fibers. To ensure that the mass ratios of pellet A and B in this example are 50 - 60% and 50 - 40%, at this time k = 1 should be taken, and N A = sin[π(t - 15) / 30] + 11, N A is maintained at 10 - 12 rpm, N B = 20 - N A = -sin[π(t - 15) / 30] + 9, N B corresponds to 10 - 8 rpm. At the same time, the total rotational speed N is constant at 20 rpm, and the period is 60 s. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, add 1 g of solid KOH, stir at 30 °C for 10 days to obtain a nanofiber suspension. After suction filtration, washing, and drying, blended LCP nanofibers are obtained, with a diameter range of 200 - 500 nm, a length range of 5 - 30 μm, and an aspect ratio range of 30 - 100. Compared with the control example, with the introduction of GHB repeating units, the diameter and length in this example are significantly reduced, but the aspect ratio changes are not obvious.

[0034] Example 2

[0035] Acetylated HBA, acetylated HNA, and GHB were copolymerized in a mass ratio of 70:30:2 to obtain pellet B. Pellet A and pellet B were mixed and melt-spun to obtain a blended LCP fiber. To ensure that the mass ratios of pellet A and B in this example were 50 - 60% and 50 - 40%, k = 1 and N A = sin[π(t - 15) / 30] + 11, N A was maintained at 10 - 12 rpm, N B = 20 - N A = -sin[π(t - 15) / 30] + 9, N B corresponding to 10 - 8 rpm. At the same time, the total rotational speed N was kept constant at 20 rpm, and the period was 60 s. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, add 1 g of solid KOH, and stir at 30 °C for 10 days to obtain a nanofiber suspension. After suction filtration, washing, and drying, a blended LCP nanofiber was obtained, with a diameter range of 100 - 500 nm, a length range of 5 - 30 μm, and an aspect ratio range of 30 - 200. Compared with the control example, by introducing the GHB repeating unit, the diameter and length of this example decreased significantly, but the aspect ratio increased slightly. Compared with Example 1, by increasing the content of the GHB repeating unit, the diameter of this example decreased somewhat, and the aspect ratio increased slightly.

[0036] Example 3

[0037] Acetylated HBA, acetylated HNA, and GHB were copolymerized in a mass ratio of 70:30:3 to obtain pellet B. Pellet A and pellet B were mixed and melt-spun to obtain a blended LCP fiber. To ensure that the mass ratios of pellet A and B in this example were 50 - 60% and 50 - 40%, k = 1 and N A = sin[π(t - 15) / 30] + 11, N A was maintained at 10 - 12 rpm, N B = 20 - N A = -sin[π(t - 15) / 30] + 9, N B corresponding to 10 - 8 rpm. At the same time, the total rotational speed N was kept constant at 20 rpm, and the period was 60 s. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, add 1 g of solid KOH, and stir at 30 °C for 10 days to obtain a nanofiber suspension. After suction filtration, washing, and drying, a blended LCP nanofiber was obtained, with a diameter range of 50 - 200 nm, a length range of 5 - 30 μm, and an aspect ratio range of 50 - 400. Compared with the control example, by introducing the GHB repeating unit, the diameter and length of this example decreased significantly, and the aspect ratio increased significantly. Compared with Example 2, the diameter of this example decreased significantly, and the aspect ratio increased significantly.

[0038] Example 4

[0039] Acetylated HBA, acetylated HNA and GHB were copolymerized in a mass ratio of 70:30:4 to obtain pellet B. Pellet A and pellet B were mixed and melt-spun to obtain a blended LCP fiber. To ensure that the mass ratios of pellet A and B in this example are 50 - 60% and 50 - 40%, k = 1 should be taken at this time, N A = sin[π(t - 15) / 30] + 11, N A was maintained at 10 - 12 rpm, N B = 20 - N A = -sin[π(t - 15) / 30] + 9, N B corresponding to 10 - 8 rpm, the total rotational speed N was kept constant at 20 rpm at the same time, and the period was 60 s. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, and add 1 g of solid KOH, stir at 30 °C for 10 days to obtain a nanofiber suspension. After suction filtration, washing, and drying, blended LCP nanofibers were obtained, with a diameter range of 50 - 200 nm, a length range of 5 - 30 μm, and an aspect ratio range of 70 - 500. Compared with the control example, by introducing GHB repeating units, the diameter and length of this example decreased significantly, and the aspect ratio increased significantly. Compared with Example 3, the diameter change in this example was not obvious, and the aspect ratio increased slightly.

[0040] Example 5

[0041] Acetylated HBA, acetylated HNA and GHB were copolymerized in a mass ratio of 70:30:5 to obtain pellet B. Pellet A and pellet B were mixed and melt-spun to obtain a blended LCP fiber. To ensure that the mass ratios of pellet A and B in this example are 50 - 60% and 50 - 40%, k = 1 should be taken at this time, N A = sin[π(t - 15) / 30] + 11, N A was maintained at 10 - 12 rpm, N B = 20 - N A = -sin[π(t - 15) / 30] + 9, N B corresponding to 10 - 8 rpm, the total rotational speed N was kept constant at 20 rpm at the same time, and the period was 60 s. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, and add 1 g of solid KOH, stir at 30 °C for 10 days to obtain a nanofiber suspension. After suction filtration, washing, and drying, blended LCP nanofibers were obtained, with a diameter range of 50 - 70 nm, a length range of 5 - 30 μm, and an aspect ratio range of 100 - 500. Compared with the control example, by introducing GHB repeating units, the diameter and length of this example decreased significantly, and the aspect ratio increased significantly. Compared with Example 4, the diameter of this example decreased significantly, and the aspect ratio increased slightly.

[0042] Example 6

[0043] Acetylated HBA, acetylated HNA, and GHB were copolymerized in a mass ratio of 70:30:5 to obtain pellet B. Pellet A and pellet B were mixed and melt-spun to obtain a blended LCP fiber. To ensure that the mass ratios of pellet A and B in this example were 60 - 70% and 40 - 30%, k = 2 should be taken at this time, N A = sin[π(t - 15) / 30] + 13, N A was maintained at 12 - 14 rpm, N B = 20 - N A = -sin[π(t - 15) / 30] + 7, N B corresponding to 8 - 6 rpm. At the same time, the total rotational speed N was kept constant at 20 rpm, and the period was 60 s. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, and add 1 g of solid KOH. Stir for 10 days at 30 °C to obtain a nanofiber suspension. After suction filtration, washing, and drying, blended LCP nanofibers were obtained, with a diameter range of 50 - 70 nm, a length range of 5 - 50 μm, and an aspect ratio range of 100 - 700. Compared with Example 5, the diameter and length in this example changed insignificantly, and the aspect ratio increased slightly.

[0044] Example 7

[0045] Acetylated HBA, acetylated HNA, and GHB were copolymerized in a mass ratio of 70:30:5 to obtain pellet B. Pellet A and pellet B were mixed and melt-spun to obtain a blended LCP fiber. To ensure that the mass ratios of pellet A and B in this example were 70 - 80% and 30 - 20%, k = 3 should be taken at this time, N A = sin[π(t - 15) / 30] + 15, N A was maintained at 14 - 16 rpm, N B = 20 - N A = -sin[π(t - 15) / 30] + 5, N B corresponding to 6 - 4 rpm. At the same time, the total rotational speed N was kept constant at 20 rpm, and the period was 60 s. Take 2 g of this fiber sample, place it in 150 mL of DMSO solution, and add 1 g of solid KOH. Stir for 10 days at 30 °C to obtain a nanofiber suspension. After suction filtration, washing, and drying, blended LCP nanofibers were obtained, with a diameter range of 30 - 50 nm, a length range of 10 - 100 μm, and an aspect ratio range of 150 - 1000. Compared with Example 6, the diameter in this example decreased slightly, but the length increased significantly, and the aspect ratio increased significantly.

[0046] Table 1 Rotational speed N of the metering pump in Examples 1 - 7 A and N BRelationship between the t - function formula and the mass ratio of pellet material

[0047]

[0048] Table 2 Comparison of preparation methods and nanofiber product parameters between control examples and examples

[0049]

Claims

1. A method for preparing polyarylate nanofibers, characterized in that: Here are the steps: (1) After HBA and HNA are acetylated, they are copolymerized with GHB to obtain HBA / GHB / HNA copolymerized aromatic ester, and pellet B is prepared, wherein the weight ratio of each component is acetylated HBA: acetylated HNA: GHB = 70: 30: (1-5); the acetylated HBA and HNA are copolymerized to obtain HBA / HNA copolymerized aromatic ester, and pellet A is prepared, wherein the weight ratio of each component is acetylated HBA: acetylated HNA = 7: 3; wherein HBA is 4-hydroxybenzoic acid, HNA is 6-hydroxy-2-naphthoic acid, and GHB is 4-hydroxybutyric acid; (2) melt spinning the pellets A and B in step (1), respectively melting them through single screw extruder A and single screw extruder B, metering and conveying them through matching function numerical control metering pumps A and metering pumps B, and conveying melt A and melt B to a static mixer in a certain mass ratio, and after being fully mixed, extruding through a spinneret to obtain a blended polyarylate fiber; (3) placing the fibers spun in step (2) into dimethyl sulfoxide, adding solid potassium hydroxide, and stirring at a certain temperature for a certain period of time to obtain a polyarylate nanofiber suspension; (4) The suspension obtained in step (3) is filtered, washed with deionized water, and then placed in an oven for drying to finally obtain polyarylate nanofibers.

2. The method for preparing polyarylate nanofibers according to claim 1, characterized in that: In step (2), the sum of the speeds of the two metering pumps is the total speed N, which is constant at N = 20 rpm. The speeds of the two metering pumps are controlled by the function to change with the change of time seconds. The speed N of metering pump A is A = sin [π(t-15) / 30] + 9 + 2k, speed N of metering pump B B = N - N A = -sin [π(t-15) / 30] + 11 – 2k, t is the real time in seconds, k is a constant in revolutions per minute, which controls the speed N A and N B oscillation range.

3. The method for preparing polyarylate nanofibers according to claim 2, characterized in that: The speed of the metering pump in step (2) is N A , N B The range of is determined by the k value, which is 1-3, and the k value of the two functions is the same. t is the number of seconds of real time that keeps changing. The period of the two function relationships is 60 s. N = 20 rpm = N A + N B .

4. The method for preparing polyarylate nanofibers according to claim 1, characterized in that: In step (2), the mass ratio of pellets A and B is a variable, which is determined by N A and N B Direct control, mass proportion of pellet A or B = (N A or N B / N)×100%, the sum of the mass proportions of the two types of pellets is constant at 100%.

5. The method for preparing polyarylate nanofibers according to claim 1, characterized in that: In step (3), the corresponding relationship between the blended polyarylate fiber and the dimethyl sulfoxide-potassium hydroxide etching system is 150 mL of dimethyl sulfoxide and 1 g of potassium hydroxide solid for every 2 g of fiber, the temperature is 20-40°C, and the stirring time is 8-12 days.

6. The method for preparing polyarylate nanofibers according to claim 1, characterized in that: The polyarylate nanofibers obtained in step (4) present a uniform rigid rod-like structure with a diameter ranging from 50 to 500 nm, a length ranging from 1 to 100 μm, and an aspect ratio ranging from 30 to 1000.

7. The method for preparing polyarylate nanofibers according to claim 1, characterized in that: A polyarylate nanofiber is prepared by the preparation method described in any one of claims 1 to 6.

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