METHOD AND DEVICE FOR PREPARING MODIFIED POLY (M-PHENYLENE ISOPHTHALAMIDE) (PMIA) FIBER BY CONTINUOUS POLYMERIZATION-DRY-WET SPINNING

Abstract

The present disclosure provides a method and a device for preparing a modified poly (m-phenylene isophthalamide) (PMIA) fiber by continuous polymerization-dry-wet spinning. The method includes the following steps: (1) preparing a mixed solution of m-phenylenediamine (MPD) and a copolymerized diamine monomer in N,N-dimethylacetamide (DMAC) serving as a solvent using a cosolvent; (2) mixing isophthaloyl chloride (IPC) with the mixed solution of the MPD and the copolymerized diamine monomer in the DMAC, and conducting pre-polycondensation and polycondensation in sequence to obtain a modified PMIA resin solution; and (3) subjecting the modified PMIA resin solution to additive addition, filtration, defoaming, and dry-wet spinning to obtain the modified PMIA fiber. In the device for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning, a prepolymerization system includes a micro-mixer and a micro-reactor that are connected in sequence, and a micro-channel of the micro-reactor is designed to be heart-shaped; and a polycondensation system is a combination of multi-stage micro-screws. The present disclosure comprehensively solves the problems during preparation of the PMIA fiber. Moreover, an obtained product has a perfect structure, excellent performances, and desirable stability and controllability, and can be prepared through continuous high-efficiency production.

Claims

1. A method for preparing a modified poly (m-phenylene isophthalamide) (PMIA) fiber by continuous polymerization-dry-wet spinning, comprising the following steps: (1) preparing a mixed solution of m-phenylenediamine (MPD) and a copolymerized diamine monomer; (2) mixing isophthaloyl chloride (IPC) with the mixed solution of the MPD and the copolymerized diamine monomer, and conducting pre-polycondensation to obtain a prepolymer; and conducting polycondensation on the prepolymer to obtain a modified PMIA resin solution; and (3) subjecting the modified PMIA resin solution to additive addition, filtration, defoaming, and dry-wet spinning to obtain the modified PMIA fiber.

2. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein in step (1), a preparation method of the mixed solution of the MPD and the copolymerized diamine monomer comprises: dissolving a cosolvent in a solvent, conducting water removal with a drying system, and dissolving the copolymerized diamine monomer and the MPD in an obtained cosolvent-containing solvent.

3. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein in step (1), a solvent of the mixed solution of the MPD and the copolymerized diamine monomer is N, N-dimethylacetamide (DMAC).

4. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 2, wherein in step (1), the cosolvent is an inorganic chloride of an alkali metal or an alkaline earth metal, and the cosolvent is added at 0.1% to 10% of a mass of the solvent of the mixed solution of the MPD and the copolymerized diamine monomer.

5. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 4, wherein the inorganic chloride of the alkali metal or the alkaline earth metal is LiCl.

6. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein the copolymerized diamine monomer is at least one selected from the group consisting of 6,4-diamino-2-trifluoromethyl-2-phenylbenzimidazole, 2-(4-aminophenyl)-5-aminophenylbenzimidazole, 5-amino-2-(4-aminophenyl)benzoxazole, 5-amino-2-(4-aminophenyl)benzothiazole, 2,6-diaminobenzothiazole, 2,6-diaminopyridine, 2-(4-aminophenyl)-5-aminopyridine, 2,5-bis(4-aminophenyl)pyridine, o-chloro-p-phenylenediamine, and p-phenylenediamine; and the copolymerized diamine monomer has a molar content 0.1% to 10% that of the IPC.

7. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein in step (2), the mixing is conducted in a micro-mixer, the IPC is added into the micro-mixer in a molten state at 45 C. to 60 C., the mixed solution of the IPC and the MPD and copolymerized diamine monomer is added into the micro-mixer in a solution state at 20 C. to 10 C., and the micro-mixer is controlled at 20 C. to 60 C.; the pre-polycondensation is conducted in a micro-reactor, and the micro-reactor is controlled at 10 C. to 60 C.; and the polycondensation is conducted in a multi-stage micro-screw device, and the multi-stage micro-screw device is controlled at 20 C. to 70 C.

8. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 7, wherein the micro-reactor is in a shape selected from the group consisting of heart, circle, triangle, line, and spire.

9. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein the modified PMIA resin has an inherent viscosity of greater than or equal to 1.8 dl/g.

10. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein in step (3), the modified PMIA resin solution is added with an organic additive capable of forming a hydrogen bond with an amide group before the filtration.

11. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 10, wherein the organic additive is at least one selected from the group consisting of low-molecular-weight alcohol and acid, and a high-heat-resistant silicone; the low-molecular-weight alcohol and acid are at least one selected from the group consisting of trifluoroacetamide, trifluoroethanol, trifluoroacetic acid, hexafluoroisopropanol, ethylene glycol, glycerol, sorbic acid, and salicylic acid, and are added at 0.01 wt % to 3 wt % of a dosage of the modified PMIA resin solution; and the silicone is at least one selected from the group consisting of a polyether-modified polysiloxane and a fluorine-containing or alkoxyl-containing or hydroxyl-containing polysiloxane, and is added at 0.1 wt % to 10 wt % of a dosage of the modified PMIA resin solution.

12. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein in step (3), the dry-wet spinning comprises the following steps: passing a spinning solution through a spinneret plate and then through an air layer, and entering a first coagulation bath to obtain a nascent fiber; and pre-drafting the nascent fiber, entering a second coagulation bath, and conducting water washing, drying, dry heat stretching, heat setting, and winding/cutting to obtain the modified PMIA fiber.

13. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 12, wherein the spinneret plate has a pore size of 0.06 mm to 0.25 mm; the spinning solution passes through the air layer with a height of 2 mm to 80 mm; and the pre-drafting is conducted at a drafting speed 2 to 5 times a spinning speed of the spinning solution.

14. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 12, wherein the first coagulation bath and the second coagulation bath each are a DMAC aqueous solution; the first coagulation bath has a DMAC concentration of 20 wt % to 45 wt % and a temperature of 20 C. to 50 C., and the second coagulation bath has a DMAC concentration of 15 wt % to 40 wt % and a temperature of 30 C. to 60 C.; a plasticizing stretching factor is 1.1 to 4; the dry heat stretching is conducted at 280 C. to 350 C. and a stretching factor of 1.1 to 3; and the heat setting is conducted at 280 C. to 350 C.

15. The method for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning according to claim 1, wherein a PMIA fiber prepared by the continuous polymerization-dry-wet spinning has a breaking strength of greater than or equal to 6.0 cN/dtex, an elongation of 25% to 50%, and an initial modulus of greater than or equal to 90 cN/dtex.

16. A device for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning, comprising a raw material storage device, a prepolymerization system, a polycondensation system, a post-treatment system, a spinning system, a coagulation and water washing system, a drying system (24), a heat treatment system, a winding/cutting system (27), and a heat exchange system; wherein the prepolymerization system, the polycondensation system, and the post-treatment system are connected in sequence; the heat exchange system is separately connected with the prepolymerization system and the polycondensation system to control temperatures of the prepolymerization system and the polycondensation system; the prepolymerization system comprises a micro-mixer (9) and a micro-reactor (10) that are connected in sequence; the polycondensation system comprises a multi-stage micro-screw device (11); and the micro-reactor (10) is connected with the multi-stage micro-screw device (11).

17. The device according to claim 16, wherein the raw material storage device comprises an IPC storage tank (1), an MPD and copolymerized diamine monomer storage tank (2), a solvent storage tank (3), and a cosolvent-containing solvent storage tank (4); the IPC storage tank (1) and the MPD and copolymerized diamine monomer storage tank (2) are connected to the micro-mixer (9) through a constant-flow-rate pump (7) and a convey pipeline, respectively.

18. The device according to claim 17, wherein a solvent dehydration device (5) is connected between the MPD and copolymerized diamine monomer storage tank (2) and the cosolvent-containing solvent storage tank (4); and the IPC storage tank (1), the MPD and copolymerized diamine monomer storage tank (2), the constant-flow-rate pump (7), and the convey pipeline each are covered with a thermal insulation jacket (8).

19. The device according to claim 16, wherein the heat exchange system comprises a refrigeration cycle device and a heating cycle device; the refrigeration cycle device comprises a refrigeration medium storage tank (28), a heat exchange medium delivery pump (30), a first rotameter, and a first medium convey pipeline; the heat exchange medium delivery pump (30) and the first rotameter are connected between the refrigeration medium storage tank (28) and the micro-mixer (9), and the medium convey pipeline connects the refrigeration medium storage tank (28), the micro-mixer (9), and the micro-reactor (10) to form a circulation loop; the heating cycle device comprises a heating medium storage tank (29), the heat exchange medium delivery pump (30), a second rotameter, and a second medium convey pipeline; the heat exchange medium delivery pump (30) and the second rotameter are connected between the heating medium storage tank (29) and the multi-stage micro-screw device (11), and the medium convey pipeline connects the heating medium storage tank (29) and the multi-stage micro-screw device (11) to form a circulation loop; and the multi-stage micro-screw device (11) comprises a first-stage micro-screw device, a second-stage micro-screw device, a third-stage micro-screw device, and a fourth-stage micro-screw device that are connected in sequence; the first-stage micro-screw device to the fourth-stage micro-screw device each are covered with the thermal insulation jacket (8), and a heat medium in the heating cycle device is introduced into the thermal insulation jacket (8); the first-stage micro-screw device to the fourth-stage micro-screw device have a gradually increasing screw diameter, a gradually decreasing screw length-to-diameter (L/D ratio) ratio, a gradually decreasing screw speed, and a gradually increasing jacket temperature in sequence; the first-stage micro-screw device to the fourth-stage micro-screw device have independently a screw diameter of 15 mm to 40 mm, a screw L/D ratio of 30 to 80, a screw speed of 100 rpm to 420 rpm, and a jacket temperature of 30 C. to 60 C.; and screws of the first-stage micro-screw device to the fourth-stage micro-screw device are one or more selected from the group consisting of a single-thread screw, a double-thread screw, a triple-thread screw, and a quadruple-thread screw.

20. The device according to claim 17, wherein the heat exchange system comprises a refrigeration cycle device and a heating cycle device; the refrigeration cycle device comprises a refrigeration medium storage tank (28), a heat exchange medium delivery pump (30), a first rotameter, and a first medium convey pipeline; the heat exchange medium delivery pump (30) and the first rotameter are connected between the refrigeration medium storage tank (28) and the micro-mixer (9), and the medium convey pipeline connects the refrigeration medium storage tank (28), the micro-mixer (9), and the micro-reactor (10) to form a circulation loop; the heating cycle device comprises a heating medium storage tank (29), the heat exchange medium delivery pump (30), a second rotameter, and a second medium convey pipeline; the heat exchange medium delivery pump (30) and the second rotameter are connected between the heating medium storage tank (29) and the multi-stage micro-screw device (11), and the medium convey pipeline connects the heating medium storage tank (29) and the multi-stage micro-screw device (11) to form a circulation loop; and the multi-stage micro-screw device (11) comprises a first-stage micro-screw device, a second-stage micro-screw device, a third-stage micro-screw device, and a fourth-stage micro-screw device that are connected in sequence; the first-stage micro-screw device to the fourth-stage micro-screw device each are covered with the thermal insulation jacket (8), and a heat medium in the heating cycle device is introduced into the thermal insulation jacket (8); the first-stage micro-screw device to the fourth-stage micro-screw device have a gradually increasing screw diameter, a gradually decreasing screw length-to-diameter (L/D ratio) ratio, a gradually decreasing screw speed, and a gradually increasing jacket temperature in sequence; the first-stage micro-screw device to the fourth-stage micro-screw device have independently a screw diameter of 15 mm to 40 mm, a screw L/D ratio of 30 to 80, a screw speed of 100 rpm to 420 rpm, and a jacket temperature of 30 C. to 60 C.; and screws of the first-stage micro-screw device to the fourth-stage micro-screw device are one or more selected from the group consisting of a single-thread screw, a double-thread screw, a triple-thread screw, and a quadruple-thread screw.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0057] To describe the technical solutions in examples of the present disclosure or in the prior art more clearly, the accompanying drawings required for describing the examples or the prior art will be briefly described below. Apparently, the accompanying drawings in the following description show some examples of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

[0058] FIG. 1 shows a device and a flow chart of the continuous polymerization-dry-wet spinning in Example 1;

[0059] FIG. 2 shows a structural diagram of a heart-shaped micro-channel reactor in Example 1; and

[0060] FIG. 3 shows an infrared spectrum of a modified PMIA resin containing a copolymerized diamine monomer in Example 7.

[0061] Reference Numerals: 1. IPC storage tank; 2. MPD and copolymerized diamine monomer storage tank; 3. Solvent storage tank; 4. Cosolvent-containing solvent storage tank; 5. Dehydration device; 6. Three-way valve; 7. Constant-flow-rate pump; 8. Thermal insulation jacket; 9. Micro-mixer; 10. Micro-reactor; 11. Multi-stage micro-screw device; 12. Additive addition and mixing device; 13. Filter; 14. Defoaming kettle; 15. Spinning solution storage tank; 16. Metering pump; 17. Spinning filter; 18. Spinning assembly; 19. Coagulation bath; 20. First coagulation bath; 21. Second coagulation bath; 22. Water washing system; 23. Traction machine; 24. Drying system; 25. Dry heat stretching device; 26. Heat setting device; 27. Winding/cutting system; 28. Refrigeration medium storage tank; 29. Heating medium storage tank; and 30. Heat exchange medium delivery pump.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] In order to facilitate the understanding of the present disclosure, the present disclosure is described in detail below in conjunction with the accompanying drawings of the specification and the preferred examples, but the protection scope of the present disclosure is not limited to the following specific examples.

[0063] Unless otherwise defined, all technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are merely for the purpose of describing specific examples, and are not intended to limit the protection scope of the present disclosure.

[0064] Unless otherwise specified, various raw materials, reagents, instruments, equipment, and the like used in the present disclosure can be purchased from the market or can be prepared by existing methods.

Example 1

[0065] In the present disclosure, the examples were all conducted in a device for preparing a modified PMIA fiber by continuous polymerization-dry-wet spinning. Referring to FIG. 1, the device includes the following systems: [0066] (1) A raw material storage device includes an IPC storage tank 1, an MPD and copolymerized diamine monomer storage tank 2, a solvent storage tank 3, a cosolvent-containing solvent storage tank 4, and a dehydration device 5. In the raw material storage device, the cosolvent-containing solvent storage tank 4 is connected to the dehydration device 5, the dehydration device 5 and the solvent storage tank 3 are connected to the MPD and copolymerized diamine monomer storage tank 2, and the IPC storage tank 1 is connected to a constant-flow-rate pump 7 and the solvent storage tank 3 through a three-way valve 6. The constant-flow-rate pump 7 is connected to a micro-mixer 9, and the MPD and copolymerized diamine monomer storage tank 2 is also connected to the micro-mixer 9 through the constant-flow-rate pump. The IPC storage tank 1, the MPD and copolymerized diamine monomer storage tank 2, the constant-flow-rate pump 7, and a convey pipeline are all covered with a thermal insulation jacket 8 for controlling a temperature of raw materials before entering the micro-mixer. [0067] (2) A prepolymerization system includes a micro-mixer 9, a micro-reactor 10, a metering pump, a delivery pipe valve, and instruments (a pressure gauge and a temperature gauge). The micro-mixer 9 is connected to the micro-reactor 10. The micro-reactor is a heart-shaped micro-channel reactor shown in FIG. 2. The micro-reactor is designed to be heart-shaped, and a plurality of the heart-shaped micro-reactors is connected by micro-channels, and the micro-channels are connected to the tip and the depression of the heart shape, respectively. [0068] (3) A polycondensation system includes a multi-stage micro-screw device 11; and the multi-stage micro-screw device 11 is connected to the micro-reactor 10. [0069] (4) A post-treatment system includes an additive addition and mixing device 12, a filter 13, a defoaming kettle 14, and a spinning solution storage tank 15. [0070] (5) A spinning system includes a metering pump 16, a spinning filter 17, and a spinning assembly 18; and the spinneret assembly includes a spinneret and a spinneret plate. [0071] (6) A coagulation and water washing system includes a coagulation bath 19, a first coagulation bath 20, a second coagulation bath 21, and a water washing system 22; and the water washing system 22 includes a washing machine, a washing liquid storage tank, and a drafting roller. [0072] (7) A drying system 24 includes a dryer and a drafting roller. [0073] (8) A heat treatment system includes a dry heat stretching device 25, a heat setting device 26, a nitrogen system, and a drafting roll. [0074] (9) A winding/cutting system 27 includes a winding machine/a cutting machine.

[0075] The components in the coagulation and water washing system, the drying system 24, the heat treatment system device, and the winding/cutting system 27 are separately connected by a traction machine 23. [0076] (10) A heat exchange system includes a refrigeration medium storage tank 28, a heating medium storage tank 29, a heat exchange medium delivery pump 30, a heat exchange medium storage tank, and a rotameter. The heat exchange medium delivery pump 30 and the rotameter are connected between the refrigeration medium storage tank 28 and the micro-mixer 9, and a medium convey pipeline connects the refrigeration medium storage tank 28, the micro-mixer 9, and the micro-reactor 10 to form a circulation loop. The heat exchange medium delivery pump 30 and the rotameter are connected between the heating medium storage tank 29 and the multi-stage micro-screw device 11, and the medium convey pipeline connects the heating medium storage tank 29 and the multi-stage micro-screw device 11 to form a circulation loop. The multi-stage micro-screw device 11 includes a first-stage micro-screw device, a second-stage micro-screw device, a third-stage micro-screw device, and a fourth-stage micro-screw device that are connected in sequence; the first-stage micro-screw device to the fourth-stage micro-screw device each are covered with the thermal insulation jacket, and a heat medium in the heating cycle device is introduced into the thermal insulation jacket; the first-stage micro-screw device to the fourth-stage micro-screw device have a gradually increasing screw diameter, a gradually decreasing screw L/D ratio, a gradually decreasing screw speed, and a gradually increasing jacket temperature in sequence; the first-stage micro-screw device to the fourth-stage micro-screw device have independently a screw diameter of 15 mm to 40 mm, a screw L/D ratio of 30 to 80, a screw speed of 100 rpm to 420 rpm, and a jacket temperature of 30 C. to 60 C.; and screws of the first-stage micro-screw device to the fourth-stage micro-screw device can be a single-thread screw, a double-thread screw, a triple-thread screw, or a quadruple-thread screw.

[0077] A preparation process of Example 1 was specifically as follows:

[0078] As shown in the flow chart in FIG. 1, a DMAC mixed solution of MPD containing LiCl (2%) with a solid content of 10 wt % and 6,4-diamino-2-trifluoromethyl-2-phenylbenzimidazole were prepared according to a molar ratio of 98:2, and kept at 20 C. IPC was melt and kept at 55 C. The mixed solution and an obtained IPC cylinder were measured in equimolar amounts by a constant-flow-rate pump, mixed through the micro-mixer 9 and delivered to the heart-shaped micro-reactor 10, where the micro-mixer 9 and the micro-reactor 10 are controlled at 20 C. to 10 C. and 10 C. to 30 C., respectively. An obtained prepolymer flowing out of the micro-reactor 10 flowed into the first-stage micro-screw device to the fourth-stage micro-screw device for polycondensation. The first-stage micro-screw device had a screw diameter of 15 mm, a screw L/D ratio of 80, a screw speed of 420 rpm, and a jacket temperature of 30 C. The second-stage micro-screw device had a screw diameter of 20 mm, a screw L/D ratio of 60, a screw speed of 300 rpm, and a jacket temperature of 40 C. The third-stage micro-screw device had a screw diameter of 30 mm, a screw L/D ratio of 40, a screw speed of 220 rpm, and a jacket temperature of 50 C. The fourth-stage micro-screw device had a screw diameter of 40 mm, a screw L/D ratio of 30, a screw speed of 100 rpm, and a jacket temperature of 60 C. The screws in the first-stage micro-screw device to the fourth-stage micro-screw device were all quadruple-thread screws. An obtained polymer flowing out from the multi-stage micro-screw device 11 entered the post-treatment system, and was added with 1 wt % trifluoroethanol, filtered, and defoamed to obtain a spinning solution. The spinning solution was subjected to spinning, water washing, drying, dry heat stretching, heat setting, and winding or cutting to obtain a modified PMIA fiber. The spinneret plate had a pore size of 0.12 mm, the air layer had a height of 40 mm, and a drafting speed of pre-orientation was 3.5 times a spinning speed of the spinning solution. The first coagulation bath had a DMAC concentration of 25 wt % and a temperature of 40 C. The second coagulation bath had a DMAC concentration of 20 wt % and a temperature of 55 C. A plasticizing stretching factor was 3.0. The dry heat stretching was conducted at 310 C. and a stretching factor of 2.0. The heat setting was conducted at 320 C.

Example 2

[0079] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the spinneret plate had a pore size adjusted to 0.1 mm, an air layer was adjusted to 20 mm, and a drafting speed of the first drafting roller was adjusted to 3.0 times a spinning speed of the spinning solution. The first coagulation bath had a DMAC concentration adjusted to 35 wt % and a temperature adjusted to 40 C. The second coagulation bath had a DMAC concentration adjusted to 25 wt % and a temperature adjusted to 45 C. The plasticizing stretching factor was adjusted to 2.5. Other processes and parameters were identical with those of Example 1.

Example 3

[0080] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: an air layer was adjusted to 10 mm, and a drafting speed of the first drafting roller was adjusted to 2.0 times a spinning speed of the spinning solution. The first coagulation bath had a temperature adjusted to 35 C. The second coagulation bath had a temperature adjusted to 45 C. The plasticizing stretching factor was adjusted to 2.8. Other processes and parameters were identical with those of Example 1.

Example 4

[0081] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: an air layer was adjusted to 60 mm, and a drafting speed of the first drafting roller was adjusted to 4.0 times a spinning speed of the spinning solution. The first coagulation bath had a DMAC concentration adjusted to 30 wt % and a temperature adjusted to 25 C. The second coagulation bath had a DMAC concentration adjusted to 25 wt % and a temperature adjusted to 35 C. The plasticizing stretching factor was adjusted to 3.2. Other processes and parameters were identical with those of Example 1.

Example 5

[0082] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the dry heat stretching was conducted at a temperature adjusted to 300 C. and a factor adjusted to 1.8. The heat setting was conducted at a temperature adjusted to 310 C. Other processes and parameters were identical with those of Example 1.

Example 6

[0083] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the dry heat stretching was conducted at a temperature adjusted to 320 C. and a factor adjusted to 2.4. The heat setting was conducted at a temperature adjusted to 330 C. Other processes and parameters were identical with those of Example 1.

Example 7

[0084] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with 2-(4-aminophenyl)-5-aminophenylbenzimidazole, a molar ratio of the MPD to the copolymerized diamine monomer was 95:5, and an amount of the LiCl was adjusted to 4%, the additive was replaced with 0.05% glycerol. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

[0085] FIG. 3 showed an infrared spectrum of the modified PMIA resin containing the copolymerized diamine monomer in Example 7.

Example 8

[0086] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with 5-amino-2-(4-aminophenyl) benzoxazole, a molar ratio of the MPD to the copolymerized diamine monomer was 97:3, and an amount of the LiCl was adjusted to 3%, the additive was replaced with a 1.5% polyether-modified polysiloxane. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

Example 9

[0087] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with 5-amino-2-(4-aminophenyl) benzothiazole, a molar ratio of the MPD to the copolymerized diamine monomer was 96:4, and an amount of the LiCl was adjusted to 4%. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

Example 10

[0088] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with 2,6-diaminobenzothiazole, the additive was replaced with 0.3% sorbic acid. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

Example 11

[0089] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with 2,6-diaminopyridine, the additive was replaced with 0.1% salicylic acid. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

Example 12

[0090] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with 2-(4-aminophenyl)-5-aminopyridine, the additive was replaced with 0.2% trifluoroacetamide. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

Example 13

[0091] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with 2,5-bis(4-aminophenyl) pyridine, the additive was replaced with 2% hydroxyl-containing polysiloxane. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

Example 14

[0092] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with o-chloro-p-phenylenediamine, a molar ratio of the MPD to the copolymerized diamine monomer was 95:5, and an amount of the LiCl was adjusted to 1%, the additive was replaced with 0.2% trifluoroacetic acid. Other processes and parameters were identical with those of Example 1, to obtain a modified PMIA fiber.

Example 15

[0093] In this example, a reaction device was the same as that in Example 1, this example differed from Example 1 in that: the copolymerized diamine monomer was replaced with p-phenylenediamine, the additive was replaced with 0.8% fluorine-containing polysiloxane. Other processes and parameters were identical with containing 1, to obtain a modified PMIA fiber.

Comparative Example 1: Pure PMIA, Batch Polymerization-Wet Spinning

[0094] The PMIA was prepared by traditional tank-type batch polymerization, where resin had an inherent viscosity of 1.84, a molecular weight distribution of 1.49, and a viscosity of 28,000 cp at 50 C. A PMIA fiber was obtained by wet spinning.

Comparative Example 2: Pure PMIA, Batch Polymerization-Dry-Wet Spinning

[0095] A polymerization method was the same as that of Comparative Example 1, and the viscosity at 50 C. was 80,000 cp. The dry-wet spinning had a phenomenon of pasted plate.

Comparative Example 3: Pure PMIA, Continuous Polymerization-Wet Spinning

[0096] The PMIA was prepared by continuous polymerization, where resin had an inherent viscosity of 1.82, a molecular weight distribution of 1.39, and a viscosity of 36,000 cp at 50 C. A PMIA fiber was obtained by wet spinning.

Comparative Example 4: Pure PMIA, Continuous Polymerization-Dry-Wet Spinning

[0097] A polymerization method was the same as that of Comparative Example 3, and the viscosity at 50 C. was 76,000 cp. The dry-wet spinning had general spinnability of the spinning solution, and there are fuzziness and broken filaments.

Comparative Example 5: Pure PMIA, Continuous Polymerization-Adding Additives-Dry-Wet Spinning

[0098] 0.5 wt % ethylene glycol was added to the PMIA resin solution of Comparative Example 4, and the viscosity at 50 C. was 82,000 cp. A PMIA fiber was obtained by dry-wet spinning, and the spinnability of the spinning solution was improved to a certain extent compared with Comparative Example 4, and the occurrence frequency of fuzziness and broken filaments was reduced.

Comparative Example 6: Modified PMIA, Continuous Polymerization-Dry-Wet Spinning

[0099] A modified PMIA resin with the copolymerized diamine monomer o-chloro-p-phenylenediamine at a content of 2% (mole fraction) was prepared by continuous polymerization. The resin had an inherent viscosity of 2.08, a molecular weight distribution of 1.41, and a viscosity of 70,000 cp at 50 C. A PMIA fiber was obtained by dry-wet spinning, and the spinnability of the spinning solution was improved to a certain extent compared with Comparative Example 4, and the occurrence frequency of fuzziness and broken filaments was reduced.

TABLE-US-00001 TABLE 1 Performance comparison of Examples (E) and Comparative Examples (CE) Resin Spinning Fiber inherent solution Spinnability breaking Initial viscosity, viscosity, and fiber strength, Elongation, modulus, SN dL/ cP Preparation method morphology cN/dtex % cN/dtex E1 2.12 78000 Continuous Smooth surface 7.3 32.8 118.7 polymerization-dry-wet with less spinning fuzziness E2 2.12 78000 Continuous Smooth surface 6.5 40.3 108.6 polymerization-dry-wet with no spinning fuzziness E3 2.12 78000 Continuous Smooth surface 6.3 43.2 104.7 polymerization-dry-wet with no spinning fuzziness E4 2.12 78000 Continuous Smooth surface 7.8 30.2 125.5 polymerization-dry-wet with no spinning fuzziness E5 2.12 78000 Continuous Smooth surface 6.8 38.4 110.2 polymerization-dry-wet with no spinning fuzziness E6 2.12 78000 Continuous Smooth surface 7.5 31.8 122.5 polymerization-dry-wet with no spinning fuzziness E7 2.26 86000 Continuous Smooth surface 7.6 26 124.6 polymerization-dry-wet with no spinning fuzziness E8 2.33 88000 Continuous Smooth surface 7.1 27 118.3 polymerization-dry-wet with no spinning fuzziness E9 2.48 92000 Continuous Smooth surface 6.5 28 115.6 polymerization-dry-wet with no spinning fuzziness E10 2.36 88000 Continuous Smooth surface 6.9 32 119.8 polymerization-dry-wet with no spinning fuzziness E11 2.65 96000 Continuous Smooth surface 7.6 28 126.3 polymerization-dry-wet with no spinning fuzziness E12 2.34 88000 Continuous Smooth surface 7.8 29 124.8 polymerization-dry-wet with no spinning fuzziness E13 2.54 94000 Continuous Smooth surface 8.1 26 121.6 polymerization-dry-wet with no spinning fuzziness E14 2.26 82000 Continuous Smooth surface 7.5 28 115.1 polymerization-dry-wet with no spinning fuzziness E15 2.74 130000 Continuous Smooth surface 8.4 34 130.5 polymerization-dry-wet with no spinning fuzziness CE1 1.84 28000 Batch Desirable, 4.1 17 88.6 polymerization-wet grooved spinning surface CE2 1.84 80000 Batch Pasted plate 4.3 19 96.5 polymerization-dry-wet spinning CE3 1.82 36000 Continuous Desirable, 4.2 23 94.7 polymerization-wet grooved spinning surface CE4 1.82 76000 Continuous Fuzziness and 4.5 24 100.8 polymerization-dry-wet broken spinning filaments CE5 1.82 82000 Continuous Fuzziness and 4.6 25 102.3 polymerization-dry-wet broken spinning filaments CE6 2.08 70000 Continuous Fuzziness and 4.8 18 105.8 polymerization-dry-wet broken spinning filaments