A covalent organic framework and polyamide 6 composite fiber and its preparation method

Abstract

This invention relates to the field of polymer materials technology, and particularly to a covalent organic framework and polyamide 6 composite fiber and its preparation method. The preparation method of the covalent organic framework and polyamide 6 composite fiber includes the following steps: mixing covalent organic framework powder and polyamide 6 powder and adding them to a ball mill jar, then ball milling the mixture to obtain a spinning raw material; sequentially drying and spinning the spinning raw material to obtain nascent fibers; and then stretching the nascent fibers to obtain the covalent organic framework and polyamide 6 composite fiber. This invention enables the preparation of covalent organic framework and polyamide 6 composite fibers with excellent tensile strength and toughness. The preparation method is simple, easy to operate, and suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a covalent organic framework and polyamide 6 composite fiber and its preparation method. Background Technology

[0002] Polyamide 6 (PA6), also known as nylon 6, is an important synthetic polymer material whose main molecular chain contains repeating amide groups (-CONH-), enabling intermolecular hydrogen bonding. Due to its excellent mechanical properties, wear resistance, and ease of processing, polyamide 6 is widely used in the preparation of fibers, engineering plastics, and films. Among these, polyamide 6 fibers, as an important polyamide product, have wide applications in transportation, aerospace, defense technology, medical protection, and electronic communications due to their heat resistance, oxidation resistance, and ease of processing. However, traditional polyamide 6 fibers suffer from low tensile strength, limiting their applications. Therefore, exploring polyamide 6 fibers with superior tensile strength is urgently needed.

[0003] Chinese patent CN 108486678 A discloses a method for preparing graphene / polyamide 6 composite fibers. The method involves obtaining a graphene / polyamide 6 composite material through in-situ polymerization, dissolving the composite material in formic acid to form a solution, and then preparing the graphene / polyamide 6 composite fibers using wet spinning. These composite fibers exhibit high tensile strength. However, the in-situ polymerization process in this invention is complex, has high production costs, and is difficult to scale up for mass production.

[0004] Therefore, exploring a simple process to obtain polyamide 6 fibers with excellent tensile strength is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention provides a method for preparing covalent organic framework and polyamide 6 composite fibers. The method involves combining a covalent organic framework with polyamide 6 to prepare covalent organic framework and polyamide 6 composite fibers with excellent tensile strength and toughness. The preparation method is simple, easy to operate, and suitable for large-scale production.

[0006] The present invention also provides a covalent organic framework and polyamide 6 composite fiber, which is prepared by the above preparation method. Therefore, the covalent organic framework and polyamide 6 composite fiber has both excellent tensile strength and toughness.

[0007] The first aspect of the present invention provides a method for preparing a covalent organic framework and polyamide 6 composite fiber, comprising the following steps:

[0008] Covalent organic framework powder and polyamide 6 powder were mixed and added to a ball mill jar, and then ball milled to obtain spinning raw material;

[0009] The spinning raw material is sequentially dried and spun to obtain nascent fibers.

[0010] The nascent fibers are stretched to obtain the covalent organic framework and polyamide 6 composite fiber.

[0011] The method for preparing covalent organic framework and polyamide 6 composite fiber as described above, wherein the covalent organic framework includes TpPa-COF, and the structural formula of TpPa-COF is as shown in formula (1):

[0012]

[0013] In the preparation method of the covalent organic framework and polyamide 6 composite fiber as described above, the mass ratio of the TpPa-COF powder to the polyamide 6 powder in the spinning raw material is (0.03~0.2):10.

[0014] In the preparation method of the covalent organic framework and polyamide 6 composite fiber as described above, the mass ratio of the TpPa-COF powder to the polyamide 6 powder in the spinning raw material is (0.05~0.1):10.

[0015] The preparation method of the covalent organic framework and polyamide 6 composite fiber as described above involves mixing covalent organic framework powder and polyamide 6 powder, adding the mixture to a ball mill jar, and then ball milling the mixture. The process includes:

[0016] The covalent organic framework powder and polyamide 6 powder were mixed and added to a ball mill jar along with milling beads. The mixture was then ball-milled at a rate of 500 rpm to 700 rpm for 1 to 3 hours.

[0017] In the preparation method of the covalent organic framework and polyamide 6 composite fiber as described above, the drying treatment temperature is 80℃~100℃ and the time is 18h~24h.

[0018] In the preparation method of the covalent organic framework and polyamide 6 composite fiber as described above, the spinning temperature is 230℃~240℃.

[0019] The method for preparing the covalent organic framework and polyamide 6 composite fiber as described above, wherein the nascent fiber is subjected to a stretching treatment, including:

[0020] The nascent fibers are stretched using hot rollers at 100℃~140℃.

[0021] A second aspect of the present invention provides a covalent organic framework and polyamide 6 composite fiber, which is prepared by the method for preparing the covalent organic framework and polyamide 6 composite fiber.

[0022] Compared with the prior art, the solution of the present invention has at least the following effects:

[0023] This invention provides a method for preparing covalent organic frameworks (COFs) and polyamide 6 (PA6) composite fibers. This method involves combining COFs with PA6 to prepare composite fibers exhibiting both excellent tensile strength and toughness. The preparation method is simple, easy to operate, and suitable for large-scale production. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The structural formula of TpPa-COF of this invention is shown below;

[0026] Figure 2 This is the structural formula of the AM-COF of the present invention;

[0027] Figure 3 This is a SEM image of the covalent organic framework and polyamide 6 composite fiber in Example 3 of the present invention;

[0028] Figure 4 This is a SEM image of the polyamide 6 fiber in Comparative Example 6 of the present invention. Detailed Implementation

[0029] 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.

[0030] Where specific techniques or conditions are not specified in the embodiments of this invention, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0031] It should be noted that the use of terms such as "first" and "second" in this invention is for distinguishing similar objects and not for describing a specific order or sequence, and therefore should not be construed as a limitation of this invention.

[0032] The term "covalent organic framework" refers to a novel type of organic framework porous material with a porous structure. Its structure is mainly composed of light elements such as carbon, oxygen, and hydrogen. It has outstanding characteristics such as controllable structure, adjustable pore size, high chemical stability, large specific surface area, and low density. The covalent organic framework structure contains NH bonds, O and benzene rings.

[0033] The first aspect of the present invention provides a method for preparing a covalent organic framework and polyamide 6 composite fiber, comprising the following steps:

[0034] Covalent organic framework powder and polyamide 6 powder were mixed and added to a ball mill jar, and then ball milled to obtain spinning raw material;

[0035] The spinning raw material is successively dried and spun to obtain nascent fibers.

[0036] The nascent fibers are stretched to obtain covalent organic framework and polyamide 6 composite fibers.

[0037] The present invention does not impose any particular limitation on the specific source of the above-mentioned raw materials, which can be purchased from commercial channels or prepared according to methods known to those skilled in the art.

[0038] The present invention prepares a covalent organic framework and polyamide 6 composite fiber. Specifically, covalent organic framework powder and polyamide 6 powder are first mixed to obtain a mixture. The mixture is then added to a ball mill jar and ball-milled to obtain a spinning raw material. The ball milling process is to make the covalent organic framework powder and polyamide 6 powder more uniformly mixed, so that the two materials can interact better. The spinning raw material is then dried to obtain a dried spinning raw material. The drying process is to remove any moisture or solvent that may be present in the spinning raw material, preventing moisture or solvent from affecting the subsequent spinning process and causing uneven fiber formation. The dried spinning raw material is then spun to obtain nascent fibers. The spinning process is to transform the dried spinning raw material into a fibrous material. The nascent fibers are then stretched to orient the molecular chains of the nascent fibers, resulting in a covalent organic framework and polyamide 6 composite fiber with excellent tensile strength and toughness. The inventors analyzed this and believe the reasons are as follows: (1) By adding a covalent organic framework, the condensed state of the polyamide 6 molecular chain is improved, the intermolecular defects of polyamide 6 are reduced, thereby improving the tensile strength and toughness of the fiber; (2) The covalent organic framework structure contains NH bonds, O and benzene rings. Its NH bonds and O can form a large number of hydrogen bonds with the polyamide 6 molecular chain, and the intermolecular interaction force is strong, thereby improving the tensile strength and toughness of the fiber; (3) The covalent organic framework is a material with a porous structure. The polyamide 6 molecular chain has a linear structure and contains a large number of amide bonds (-CONH-). The porous structure of the covalent organic framework can be used to make the covalent organic framework play a clamping role, effectively embedding the polyamide 6 molecular chain into the in-plane control, forming a nano-confined effect, which enhances the interaction between the polyamide 6 molecular chains and improves the tensile strength and toughness of the fiber.

[0039] The preparation method of covalent organic framework and polyamide 6 composite fiber provided by the present invention is simple, easy to operate, and suitable for large-scale production.

[0040] In one specific embodiment, the above covalent organic framework includes TpPa-COF, the structural formula of which is shown in formula (1):

[0041]

[0042] When the covalent organic framework used is TpPa-COF, TpPa-COF can be combined with polyamide 6 to prepare a covalent organic framework and polyamide 6 composite fiber with excellent tensile strength and toughness.

[0043] In one specific embodiment, the mass ratio of TpPa-COF powder to polyamide 6 powder in the above-mentioned spinning raw material is (0.03~0.2):10.

[0044] When the mass ratio of TpPa-COF powder to polyamide 6 powder in the above-mentioned spinning raw materials is within the above-mentioned range, covalent organic framework and polyamide 6 composite fibers with excellent mechanical properties can be prepared.

[0045] For example, in the above-mentioned spinning raw materials, the mass ratio of TpPa-COF powder to polyamide 6 powder can be any one or any two of 0.03:10, 0.04:10, 0.05:10, 0.06:10, 0.07:10, 0.08:10, 0.09:10, 0.1:10, and 0.2:10.

[0046] In one specific embodiment, the mass ratio of TpPa-COF to polyamide 6 powder in the above-mentioned spinning raw material is (0.05~0.1):10.

[0047] When the mass ratio of TpPa-COF powder to polyamide 6 powder in the above-mentioned spinning raw materials is within the above range, a covalent organic framework and polyamide 6 composite fiber with excellent tensile strength and toughness can be prepared.

[0048] For example, in the above-mentioned spinning raw materials, the mass ratio of TpPa-COF powder to polyamide 6 powder can be any one or any two of 0.05:10, 0.06:10, 0.07:10, 0.08:10, 0.09:10, 0.1:10.

[0049] In one specific embodiment, covalent organic framework powder and polyamide 6 powder are mixed and added to a ball mill jar, and then ball milled using a ball mill, including:

[0050] The covalent organic framework powder and polyamide 6 powder were mixed and added to a ball mill jar along with milling beads. The mixture was then ball-milled at a rate of 500 rpm to 700 rpm for 1 to 3 hours.

[0051] The present invention ball-mills the mixture of covalent organic framework powder and polyamide 6 powder through the above process, so that the covalent organic framework powder and polyamide 6 powder can be mixed more uniformly, and the two materials can interact better, which is beneficial to the subsequent preparation of covalent organic framework and polyamide 6 composite fibers with excellent tensile strength and toughness.

[0052] In one specific embodiment, the temperature of the above drying process is 80℃~100℃ and the time is 18h~24h.

[0053] When the temperature and time parameters of the above drying process are each within the above range, the moisture or solvent that may be present in the spinning raw material can be effectively removed.

[0054] In one specific embodiment, the temperature of the above-mentioned spinning treatment is 230°C to 240°C.

[0055] When the temperature parameters of the above spinning treatment are within the above range, the spinning raw material can be effectively melted and has good fluidity, so that the covalent organic framework and polyamide 6 in the spinning raw material can better form a composite structure during the spinning treatment, promoting the interaction between the covalent organic framework and polyamide 6, which is beneficial to the subsequent preparation of covalent organic framework and polyamide 6 composite fibers with excellent tensile strength and toughness.

[0056] In one specific embodiment, the nascent fibers are subjected to a stretching treatment, including:

[0057] The nascent fibers are stretched using hot rollers at 100℃~140℃.

[0058] When nascent fibers are stretched using hot rollers at 100℃~140℃, the molecular chains of the nascent fibers can be arranged in a more orderly manner, which is beneficial for obtaining covalent organic framework and polyamide 6 composite fibers that have both excellent tensile strength and toughness.

[0059] A second aspect of the present invention provides a covalent organic framework and polyamide 6 composite fiber, which is prepared by the above-described method for preparing covalent organic framework and polyamide 6 composite fibers. Therefore, this covalent organic framework and polyamide 6 composite fiber possesses both excellent tensile strength and toughness.

[0060] The embodiments of the present invention will be described in detail through the following examples and comparative examples.

[0061] Example 1

[0062] The method for preparing covalent organic framework and polyamide 6 composite fiber provided in this embodiment includes the following steps:

[0063] 30mg TpPa-COF (structural formula as shown) Figure 1 (As shown) was added to the first zirconia ball milling jar at room temperature and 40g of first zirconia ball milling beads were added. Then, it was ball milled at a rate of 600rpm for 2h to obtain uniform TpPaCOF powder.

[0064] After mixing uniform TpPaCOF powder and 10g of polyamide 6 powder, a mixture was obtained. The mixture was added to a second zirconia ball mill jar and 40g of second zirconia ball milling beads were added. Then, the mixture was ball milled at a rate of 600rpm for 2h to obtain uniform spinning raw material.

[0065] The uniform spinning raw material was placed in a vacuum oven at 100℃ for 24 hours to dry it, and the dried spinning raw material was obtained.

[0066] Primary fibers are obtained by spinning the dried spinning raw material at 235°C using a melt spinning method.

[0067] The nascent fibers were stretched using a 140℃ hot roller to obtain a covalent organic framework and polyamide 6 composite fiber.

[0068] Example 2

[0069] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this embodiment is the same as that in Example 1, except that:

[0070] Replace 30mg TpPa-COF with 50mg TpPa-COF.

[0071] Example 3

[0072] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this embodiment is the same as that in Example 1, except that:

[0073] Replace 30mg TpPa-COF with 100mg TpPa-COF.

[0074] Example 4

[0075] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this embodiment is the same as that in Example 1, except that:

[0076] Replace 30mg TpPa-COF with 200mg TpPa-COF.

[0077] Comparative Example 1

[0078] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this comparative example is the same as that in Example 1, except that:

[0079] Replace 30mg TpPa-COF with 10mg TpPa-COF.

[0080] Comparative Example 2

[0081] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this comparative example is the same as that in Example 1, except that:

[0082] Replace 30mg TpPa-COF with 30mg AM-COF (structural formula as follows) Figure 2 (As shown).

[0083] Comparative Example 3

[0084] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this comparative example is the same as that in Example 1, except that:

[0085] Replace 30mg TpPa-COF with 50mg AM-COF.

[0086] Comparative Example 4

[0087] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this comparative example is the same as that in Example 1, except that:

[0088] Replace 30mg TpPa-COF with 100mg AM-COF.

[0089] Comparative Example 5

[0090] The preparation method of the covalent organic framework and polyamide 6 composite fiber provided in this comparative example is the same as that in Example 1, except that:

[0091] Replace 30mg TpPa-COF with 200mg AM-COF.

[0092] Comparative Example 6 (without TpPa-COF)

[0093] The method for preparing polyamide 6 fibers provided in this comparative example includes the following steps:

[0094] 10g of polyamide 6 powder was added to a zirconia ball mill jar and 40g of zirconia ball milling beads were added. The mixture was then ball milled at 600rpm for 2 hours to obtain a uniform spinning raw material.

[0095] The uniform spinning raw material was placed in a vacuum oven at 100℃ for 24 hours to dry it, and the dried spinning raw material was obtained.

[0096] Primary fibers are obtained by spinning the dried spinning raw material at 235°C using a melt spinning method.

[0097] Polyamide 6 fiber is obtained by stretching the nascent fiber using a 140℃ hot roller.

[0098] Table 1 shows the mass of TpPa-COF, AM-COF, and polyamide 6 for each example and comparative example.

[0099] project TpPa-COF (mg) AM-COF (mg) Polyamide 6(g) Example 1 30 0 10 Example 2 50 0 10 Example 3 100 0 10 Example 4 200 0 10 Comparative Example 1 10 0 10 Comparative Example 2 0 30 10 Comparative Example 3 0 50 10 Comparative Example 4 0 100 10 Comparative Example 5 0 200 10 Comparative Example 6 0 0 10

[0100] Test Example 1

[0101] This test example provides a morphological characterization experiment for covalent organic framework and polyamide 6 composite fibers:

[0102] Scanning electron microscopy (SEM) was performed on the covalent organic framework and polyamide 6 composite fiber in Example 3 of the present invention and the polyamide 6 fiber in Comparative Example 6, respectively. The test results are as follows: Figure 3 and Figure 4 As shown.

[0103] Depend on Figure 3 and Figure 4 It can be seen that the surface morphology of covalent organic framework materials and polyamide 6 composite fibers is similar to that of polyamide 6 fibers. Both have smooth and regular surface morphology and no obvious pores, exhibiting obvious fiber characteristics, indicating that the fibers are uniformly formed during the spinning process.

[0104] Test Example 2

[0105] This test example provides a performance characterization experiment for a covalent organic framework and polyamide 6 composite fiber:

[0106] The covalent organic framework and polyamide 6 composite fibers of Examples 1-4, Comparative Examples 1-5, and the polyamide 6 fiber in Comparative Example 6 were used as the test fibers and the following tests were performed. The test results are shown in Table 2.

[0107] Tensile strength / MPa: Take a 5cm fiber to be tested, apply anti-slip tape to 1cm at both ends, and perform tensile testing through a universal testing machine, with a tensile speed of 50mm / min.

[0108] Toughness / MJ·m -3 The toughness of the fiber under test is obtained by integrating the stress-strain tensile curve of the fiber.

[0109] Table 2 Test Results

[0110] project Tensile strength / MPa <![CDATA[Toughness / MJ·m -3 > Example 1 922 113 Example 2 1030 150 Example 3 1095 151 Example 4 1035 123 Comparative Example 1 765 80 Comparative Example 2 472 81 Comparative Example 3 566 122 Comparative Example 4 775 125 Comparative Example 5 494 47 Comparative Example 6 794 122

[0111] As shown in Table 2, compared with the polyamide 6 fiber in Comparative Example 6, the tensile strength of the covalent organic framework and polyamide 6 composite fibers in Examples 1-4 of the present invention is significantly improved. Compared with the polyamide 6 fiber in Comparative Example 6, the covalent organic framework and polyamide 6 composite fibers in Examples 2-3 of the present invention exhibit both excellent tensile strength and excellent toughness, which can meet the requirements of ultra-high-end application fields for the toughness performance of fiber materials.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a covalent organic framework and polyamide 6 composite fiber, characterized by, The method comprises the following steps: TpPa-COF powder and polyamide 6 powder are mixed and then added into a ball mill tank, and then ball milling treatment is performed by a ball mill to obtain a spinning raw material; wherein the mass ratio of the TpPa-COF powder to the polyamide 6 powder is (0.03-0.2):10; The spinning raw material is subjected to dry treatment and melt spinning treatment in sequence to obtain a nascent fiber; The nascent fiber is subjected to drawing treatment to obtain the covalent organic framework and polyamide 6 composite fiber; The structural formula of the TpPa-COF is shown in formula (1): ； Formula (1).

2. The method for preparing the covalent organic framework and polyamide 6 composite fiber according to claim 1, characterized in that, In the spinning raw material, the mass ratio of the TpPa-COF powder to the polyamide 6 powder is (0.05-0.1):

10.

3. The method for preparing the covalent organic framework and polyamide 6 composite fiber according to claim 1, characterized in that, Covalent organic framework powder and polyamide 6 powder are mixed and then added into a ball mill tank, and then ball milling treatment is performed by a ball mill, comprising: Covalent organic framework powder and polyamide 6 powder are mixed and then added into a ball mill tank and ball milling beads are added, and then ball milling treatment is performed by a ball mill at a speed of 500 rpm-700 rpm for 1 h-3 h.

4. The method for preparing the covalent organic framework and polyamide 6 composite fiber according to claim 1, characterized in that, The dry treatment is performed at a temperature of 80-100 °C for 18-24 h.

5. The method for preparing the covalent organic framework and polyamide 6 composite fiber according to claim 1, characterized in that, The melt spinning treatment is performed at a temperature of 230-240 °C.

6. The method for preparing the covalent organic framework and polyamide 6 composite fiber according to claim 1, characterized in that, The nascent fiber is subjected to drawing treatment, comprising: The nascent fiber is subjected to drawing treatment by a 100-140 °C hot roller.

7. A covalent organic framework and polyamide 6 composite fiber, characterized in that, The covalent organic framework and polyamide 6 composite fiber is prepared by the method according to any one of claims 1-6.

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