A method for wet spinning carbon nanotubes to form fibers by using dual polymers to assist dispersion

Abstract

A method for wet spinning fiber by assisting carbon nanotubes with double polymer dispersion, comprising the following steps: uniformly dispersing modified carbon nanotubes purified and oxidized at 300°C-400°C in a concentrated sulfuric acid solution of para-aramid fiber or meta-aramid fiber to form a spinning solution; then injecting the spinning solution into a deionized polyvinyl alcohol solution through a syringe at a uniform speed, and after the replacement is completed, drying and collecting the fiber. The present invention realizes the fiber preparation of industrial-grade carbon nanotubes on the basis of ensuring the performance of carbon nanotube fibers, has universality and versatility, can realize the large-scale preparation of carbon nanotube fibers, and has broad application scenarios in special applications, special fabrics, etc.

Description

Technical Field

[0001] The invention belongs to the field of spinning methods and processes, and particularly relates to a method for wet spinning of carbon nanotubes into fibers by using a double polymer to assist in dispersion. Background Art

[0002] Carbon nanotube fiber is a macroscopic continuous fiber material with a micron diameter, which is constructed with nanoscale carbon nanotubes as assembly units.

[0003] The current methods for preparing carbon nanotube fibers mainly include carbon nanotube vapor phase fiber formation, carbon nanotube array fiber formation and carbon nanotube wet (solution) fiber formation. Among them, carbon nanotube wet (solution) fiber formation technology is the easiest to industrialize and has achieved certain results on other polymers.

[0004] In order to realize the industrialization, industrialization and mass production of carbon nanotube fiber synthesis, the use of carbon nanotube wet fiberization technology is considered.

[0005] At present, there is still a large gap between the performance of carbon nanotube fibers and single carbon nanotubes, indicating that the mechanical strength of carbon nanotube fibers does not mainly depend on the mechanical strength of single carbon nanotubes, but on the microscopic assembly structure of carbon nanotubes.

[0006] Due to the large specific surface area and strong interaction force of carbon nanotubes, carbon nanotubes are easily entangled and agglomerated, which makes them difficult to disperse and limits their wide application. In addition, the performance of carbon nanotube fibers is closely related to the interaction force between carbon nanotubes inside them. Randomly distributed carbon nanotubes have a small contact area, weak interaction force between carbon nanotubes, and are prone to form structural defects inside the fiber, which in turn leads to a significant decrease in mechanical properties, electrical conductivity, etc.

[0007] In summary, the existing carbon nanotube fiber-forming process is difficult to achieve industrial production of carbon nanotube fibers due to its special materials or equipment and other factors, and the performance of the obtained fibers is still far behind that of single carbon nanotubes. Therefore, a new universal carbon nanotube fiber-forming technology is needed. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a method and application of wet spinning fiberization by using dual polymers to assist carbon nanotubes in dispersion.

[0009] The present invention is achieved through the following technical solutions.

[0010] The method for wet spinning fiber formation by using dual polymers to assist carbon nanotube dispersion includes the following steps.

[0011] (1) The polymer A is placed in concentrated sulfuric acid and waited for it to be completely dissolved to obtain solution A.

[0012] (2) Placing the carbon nanotubes in a muffle furnace, purifying at 300°C-400°C, and then functionalizing the carbon nanotubes through oxidation treatment to obtain modified carbon nanotubes.

[0013] (3) The modified carbon nanotubes prepared in step (2) are uniformly dispersed in solution A prepared in step (1) to obtain solution B, which is used as a spinning solution.

[0014] (4) Dissolve polymer B in deionized water at a weight percentage of 0.99% to 10.7% to serve as a coagulation bath.

[0015] (5) Solution B, i.e., the spinning solution, is injected into the coagulation bath at a uniform rate through a syringe, and then the solution B is replaced in the coagulation bath, and the fibers are dried and collected.

[0016] The solution B (spinning solution) prepared in steps (1) to (3) of the present invention comprises, by weight percentage, 0.05%-0.22% of polymer A, 95.9%-99.4% of concentrated sulfuric acid, and 0.5%-3.8% of modified carbon nanotubes.

[0017] The polymer A comprises one or a combination of para-aramid fiber or meta-aramid fiber; the polymer B is polyvinyl alcohol; the concentrated sulfuric acid is a 95%-98% aqueous solution; the modified carbon nanotubes are oxidized carbon nanotubes, and the carbon nanotubes comprise one or a combination of single-walled carbon nanotubes or multi-walled carbon nanotubes.

[0018] The present invention realizes the fiber-forming preparation of industrial-grade carbon nanotubes while ensuring the performance of carbon nanotube fibers. It has universality and versatility, can realize the large-scale preparation of carbon nanotube fibers, and has broad application scenarios in special applications, special fabrics, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The overall surface morphology of the samples described in Examples 2-5 of the present invention. Among them, P1-CNTF, P2-CNTF, P3-CNTF, and P4-CNTF correspond to Examples 2, 3, 4, and 5.

[0020] Figure 2 The partial enlarged morphology of the sample surface described in Examples 2-5 of the present invention. Among them, P1-CNTF, P2-CNTF, P3-CNTF, and P4-CNTF correspond to Examples 2, 3, 4, and 5.

[0021] Figure 3The thermogravimetric curves of the samples described in Examples 1 to 5 of the present invention are shown below. Among them, CNTF, P1-CNTF, P2-CNTF, P3-CNTF, and P4-CNTF correspond to Examples 1, 2, 3, 4, and 5.

[0022] Figure 4 The stress curve diagram of the samples described in Examples 2-5 of the present invention, wherein P1-CNTF, P2-CNTF, P3-CNTF, and P4-CNTF correspond to Examples 2, 3, 4, and 5.

[0023] Figure 5 The strain curves of the samples described in Examples 2-5 of the present invention are shown in FIG. 1 , wherein P1-CNTF, P2-CNTF, P3-CNTF, and P4-CNTF correspond to Examples 2, 3, 4, and 5.

[0024] Figure 6 The conductivity curves of the samples described in Examples 2-5 of the present invention are shown in FIG. 1 , wherein P1-CNTF, P2-CNTF, P3-CNTF, and P4-CNTF correspond to Examples 2, 3, 4, and 5. Implementation

[0025] The present invention will be further illustrated by the following examples. Example 1

[0026] A method for preparing polymer carbon nanotube fibers by double polymer-assisted carbon nanotube dispersion wet spinning fiber formation is provided, and the steps are as follows.

[0027] (1) Place 1.5 g of para-aramid kevlar (para-aramid fiber) in 500 ml of 98% concentrated sulfuric acid for 5-7 days until it is completely dissolved to obtain solution A.

[0028] (2) The carbon nanotubes were purified at 400°C in a muffle furnace for 2 h, and then oxidized in a mixed solution of 98% concentrated sulfuric acid and 70% concentrated nitric acid in a volume ratio of 3:1 for 1 h. The modified carbon nanotubes were washed three times with deionized water and then filtered and dried to obtain modified carbon nanotubes.

[0029] (3) Take out 20 g of solution A, add 0.6 g of modified carbon nanotubes, and use magnetic stirring to fully disperse the modified carbon nanotubes in solution A to obtain solution B, which is the polymer spinning solution.

[0030] (4) Pour 1 L of deionized water into the water tank to serve as a coagulation bath.

[0031] (5) The obtained solution B is drawn into a syringe with a diameter of 22.25 mm and a capacity of 10 mL, and is injected into the coagulation bath at a constant speed by a stepper motor. After the fiber is completely replaced in the coagulation bath, it is dried and collected to obtain polymer carbon nanotube fibers, which are recorded as CNTF. Example 2

[0032] A method for preparing polymer carbon nanotube fibers by double polymer-assisted carbon nanotube dispersion wet spinning fiber formation is provided, and the steps are as follows.

[0033] (1) Place 1.5 g of para-aramid kevlar (para-aramid fiber) in 500 ml of 98% concentrated sulfuric acid for 5-7 days until it is completely dissolved to obtain solution A.

[0034] (2) The carbon nanotubes were purified at 400°C in a muffle furnace for 2 h, and then oxidized in a mixed solution of 98% concentrated sulfuric acid and 70% concentrated nitric acid in a volume ratio of 3:1 for 1 h. The modified carbon nanotubes were washed three times with deionized water and then filtered and dried to obtain modified carbon nanotubes.

[0035] (3) Take out 20 g of solution A, add 0.6 g of modified carbon nanotubes, and use magnetic stirring to fully disperse the modified carbon nanotubes in solution A to obtain solution B, which is the polymer spinning solution.

[0036] (4) Add 2 g of polyvinyl alcohol crystals into 100 ml of deionized water and fully dissolve them in a water tank to obtain solution C, which is the polymer coagulation bath.

[0037] (5) The obtained solution B is drawn up through a syringe with a diameter of 22.25 mm and a capacity of 10 mL, and is injected into solution C at a constant speed by a stepper motor. After the fiber is replaced in the coagulation bath, it is dried and collected to obtain dual-polymer carbon nanotube fibers, which are recorded as P1-CNTF. Example 3

[0038] A method for preparing polymer carbon nanotube fibers by double polymer-assisted carbon nanotube dispersion wet spinning fiber formation is provided, and the steps are as follows.

[0039] (1) Place 1.5 g of para-aramid kevlar (para-aramid fiber) in 500 ml of 98% concentrated sulfuric acid for 5-7 days until it is completely dissolved to obtain solution A.

[0040] (2) The carbon nanotubes were purified at 400°C in a muffle furnace for 2 h, and then oxidized in a mixed solution of 98% concentrated sulfuric acid and 70% concentrated nitric acid in a volume ratio of 3:1 for 1 h. The modified carbon nanotubes were washed three times with deionized water and then filtered and dried to obtain modified carbon nanotubes.

[0041] (3) Take out 20 g of solution A, add 0.6 g of modified carbon nanotubes, and use magnetic stirring to fully disperse the modified carbon nanotubes in solution A to obtain solution B, which is the polymer spinning solution.

[0042] (4) Add 4 g of polyvinyl alcohol crystals into 100 ml of deionized water and fully dissolve them in a water tank to obtain solution C, which is the polymer coagulation bath.

[0043] (5) The obtained solution B is drawn into a syringe with a diameter of 22.25 mm and a capacity of 10 mL and injected into the coagulation bath at a constant speed by a stepper motor. After the displacement of the fiber in the coagulation bath is completed, it is dried and collected to obtain dual-polymer carbon nanotube fibers, which are recorded as P2-CNTF. Example 4

[0044] A method for preparing polymer carbon nanotube fibers by double polymer-assisted carbon nanotube dispersion wet spinning fiber formation is provided, and the steps are as follows.

[0045] (1) Place 1.5 g of aramid 1313 (meta-aramid fiber) in 500 ml of 98% concentrated sulfuric acid for 5-7 days until it is completely dissolved to obtain solution A.

[0046] (2) The carbon nanotubes were purified at 400°C in a muffle furnace for 2 h, and then oxidized in a mixed solution of 98% concentrated sulfuric acid and 70% concentrated nitric acid in a volume ratio of 3:1 for 1 h. The modified carbon nanotubes were washed three times with deionized water and then filtered and dried to obtain modified carbon nanotubes.

[0047] (3) Take out 20 g of solution A, add 0.6 g of modified carbon nanotubes, and use magnetic stirring to fully disperse the modified carbon nanotubes in solution A to obtain solution B, which is the polymer spinning solution.

[0048] (4) Add 6 g of polyvinyl alcohol crystals into 100 ml of deionized water and fully dissolve them in a water tank to obtain solution C, which is the polymer coagulation bath.

[0049] (5) The obtained solution B is drawn into a syringe with a diameter of 22.25 mm and a capacity of 10 mL, and is injected into the coagulation bath at a constant speed by a stepper motor. After the fiber is completely replaced in the coagulation bath, it is dried and collected to obtain dual-polymer carbon nanotube fibers, which are recorded as P3-CNTF. Example 5

[0050] A method for preparing polymer carbon nanotube fibers by double polymer-assisted carbon nanotube dispersion wet spinning fiber formation is provided, and the steps are as follows.

[0051] (1) Place 1.5 g of aramid 1313 (meta-aramid fiber) in 500 ml of 98% concentrated sulfuric acid for 5-7 days until it is completely dissolved to obtain solution A.

[0052] (2) The carbon nanotubes were purified at 400°C in a muffle furnace for 2 h, and then oxidized in a mixed solution of 98% concentrated sulfuric acid and 70% concentrated nitric acid in a volume ratio of 3:1 for 1 h. The modified carbon nanotubes were washed three times with deionized water and then filtered and dried to obtain modified carbon nanotubes.

[0053] (3) Take out 20 g of solution A, add 0.6 g of modified carbon nanotubes, and use magnetic stirring to fully disperse the modified carbon nanotubes in solution A to obtain solution B, which is the polymer spinning solution.

[0054] (4) Add 8 g of polyvinyl alcohol crystals into 100 ml of deionized water and fully dissolve them in a water tank to obtain solution C, which is the polymer coagulation bath.

[0055] (5) The obtained solution B is drawn into a syringe with a diameter of 22.25 mm and a capacity of 10 mL, and is injected into the coagulation bath at a constant speed by a stepper motor. After the fiber is completely replaced in the coagulation bath, it is dried and collected to obtain dual-polymer carbon nanotube fibers, which are recorded as P4-CNTF.

Claims

1. A method for wet spinning carbon nanotubes to form fibers by assisting the dispersion of carbon nanotubes with dual polymers, characterized in that The steps include: (1) placing the polymer A in concentrated sulfuric acid and completely dissolving it to obtain a solution A; (2) placing the carbon nanotubes in a muffle furnace, purifying them at 300°C-400°C, and then functionalizing the carbon nanotubes through oxidation treatment to obtain modified carbon nanotubes; (3) uniformly dispersing the modified carbon nanotubes prepared in step (2) in solution A prepared in step (1) to obtain solution B as a spinning solution; (4) dissolving polymer B in deionized water at a weight percentage of 0.99% to 10.7% to serve as a coagulation bath; (5) Inject solution B into the coagulation bath at a uniform rate through a syringe, wait for it to be completely replaced in the coagulation bath, and then dry and collect the fibers; The solution B prepared in steps (1) to (3) comprises, by weight percentage, 0.05% to 0.22% of polymer A, 95.9% to 99.4% of concentrated sulfuric acid, and 0.5% to 3.8% of modified carbon nanotubes; The polymer A includes one or a combination of para-aramid fiber or meta-aramid fiber; the polymer B is polyvinyl alcohol; the concentrated sulfuric acid is a 95%-98% aqueous solution; and the carbon nanotubes include one or a combination of single-walled carbon nanotubes or multi-walled carbon nanotubes.

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