CN116254622A

CN116254622A - Hollow fiber, preparation method thereof and nanocomposite

Info

Publication number: CN116254622A
Application number: CN202211606458.2A
Authority: CN
Inventors: 吕卫帮; 杨丹丹; 曲抒旋
Original assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Current assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Priority date: 2022-12-14
Filing date: 2022-12-14
Publication date: 2023-06-13

Abstract

The invention provides a hollow fiber, a preparation method thereof and a composite material. The hollow fiber comprises nano materials and orientation aids; the mass ratio of the nano material to the orientation auxiliary agent is (5-20): 1. The preparation method of the hollow fiber comprises the following steps: mixing the nano material with an orientation auxiliary agent to obtain spinning solution; and spinning or 3D printing the spinning solution to obtain the hollow fiber. According to the invention, the hollow fiber is beneficial to improving the orientation degree of the nano material in the fiber by adding the orientation auxiliary agent with specific content, so that the problems of difficult dispersion, low content and poor orientation of the nano material in the resin are effectively avoided; so that the composite material comprising the hollow fiber has excellent mechanical properties.

Description

Hollow fiber, preparation method thereof and nanocomposite

Technical Field

The invention belongs to the technical field of composite materials, and particularly relates to a hollow fiber, a preparation method thereof and a nanocomposite.

Background

Nanomaterials, such as carbon nanotubes, graphene, boron nitride, and the like, have excellent mechanical strength, electrical conductivity, and thermal conductivity, and properties superior to those of low density and high aspect ratio, so that the force, electrical and thermal properties are far superior to those of carbon fibers, and are therefore recognized as ideal reinforcement phases of light high-performance composite materials after carbon fibers. A great deal of research has demonstrated that adding CNTs, graphene, etc. to polymer resins can significantly improve the mechanical and electrical properties of the polymer resins. However, since the specific surface area of the nanomaterial is large, it is difficult to uniformly disperse in the resin matrix, resulting in difficulty in achieving a desired height of the nanocomposite. Therefore, how to obtain high-performance nanocomposite materials has attracted more and more attention.

In the prior art, nanocomposite materials are typically prepared by mixing nanoreinforcements with resins by direct dispersion and then pressing the mixture into a composite material using a mold. However, since the nanomaterial has a large specific surface area, it is a great challenge to uniformly disperse in the resin, and the existing methods include using a dispersing agent, surface chemical grafting treatment, etc., but the dispersing agent has poor bonding with the resin, and chemical grafting may damage the structure of the nanomaterial itself, and reduce the performance thereof. Therefore, at present, no method for uniformly dispersing the nano material in the resin exists, and the prepared nano composite material has low reinforcement content, poor dispersibility and almost no orientation, so that the mechanical and electrical properties are low.

The preparation method of pre-assembling the nano material into macroscopic body and then compounding the macroscopic body with the resin can avoid the problem of difficult dispersion of the nano material in the resin matrix, and can realize high content of the nano reinforcement in the composite material, thereby improving the performance of the composite material. For example, the carbon nanotubes are first prepared into a film and then compounded with resin to obtain a carbon nanotube film composite material with high carbon tube content, but the carbon nanotube film is usually unoriented, so that the composite material is also poor in orientation, resulting in poor mechanical properties. The orientation of the carbon nanotube film can be improved by methods such as drawing orientation, but the compactness of the oriented film is higher, and the difficulty of resin infiltration is increased. The high-orientation carbon nanotube film can be obtained by a carbon nanotube array film drawing method, but the preparation process of the carbon nanotube array is complex, and the mass production is difficult, so that the application of the carbon nanotubes is greatly limited.

Therefore, development of a nanocomposite reinforcement and a preparation method thereof improves orientation of the nanomaterial, enables the nanomaterial to be uniformly dispersed in resin, and improves mechanical properties and conductivity of the composite, which is a technical problem to be solved in the art.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide a hollow fiber, a preparation method thereof and a nanocomposite. The orientation auxiliary agent is added into the raw materials of the hollow fiber, and the orientation auxiliary agent is compounded with the nano material in a specific proportion, so that the orientation degree of the nano material in the fiber can be improved, the obtained hollow fiber is combined with the resin through an impregnation or vacuum infusion method, and the problems of difficult dispersion, low content and poor orientation of the nano material in the resin are effectively avoided; so that the composite material comprising the hollow fiber has excellent mechanical properties.

To achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a hollow fiber, the hollow fiber comprising nanomaterial and an orientation aid as raw materials; the mass ratio of the nano material to the orientation auxiliary agent is (5-20): 1.

According to the invention, the orientation auxiliary agent is used for generating orientation in the system, so that the nano material is induced to generate orientation, and the orientation degree of the nano material is improved; by adjusting the content of the orientation auxiliary agent, the controllability of the fiber structure and the shape can be effectively improved, and the mechanical property of the hollow fiber is improved. Preferably, the mass ratio of the nanomaterial to the orientation aid is (5-20): 1, for example, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, etc.

In the invention, the mass ratio of the nano material to the orientation auxiliary agent is in a specific range, the orientation degree of the nano material is higher, and the mechanical property of the fiber is better.

Preferably, the nanomaterial comprises at least one of carbon nanotubes, graphene oxide, cellulose, or boron nitride.

The length of the carbon nanotubes is preferably 10 to 200. Mu.m, for example, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, etc., and more preferably 20 to 50 μm.

Preferably, the carbon nanotubes comprise single-walled carbon nanotubes and/or multi-walled carbon nanotubes.

The graphene and graphene oxide may have a sheet diameter of 0.5 to 20 μm, for example, 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, or the like, and more preferably 5 to 15 μm, independently of each other.

Preferably, the cellulose has a diameter of 10 to 100nm, and may be, for example, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, or the like.

Preferably, the boron nitride comprises boron nitride nanoplatelets and/or boron nitride nanotubes.

Preferably, the orientation aid comprises at least one of graphene oxide and nanocellulose.

The graphene oxide in the orientation aid may have a sheet diameter of 0.1 to 1. Mu.m, for example, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, 0.55 μm, 0.6 μm, 0.7 μm, 0.8 μm, 1 μm, etc., and more preferably 0.2 to 0.5 μm.

The diameter of the nanocellulose in the orientation aid is preferably 2 to 10nm, and may be, for example, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, etc.

Preferably, the hollow fibers have a length of 10cm or more, for example, 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 45cm, 50cm, 55cm, 60cm, 65cm, 70cm, 75cm, 80cm, 85cm, 90cm, 95cm, 100cm, etc.

Preferably, the hollow fiber has a wall thickness of 2 to 100. Mu.m, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, etc.

Preferably, the hollow fiber has an inner diameter of 10 to 200. Mu.m, for example, 20. Mu.m, 30. Mu.m, 40. Mu.m, 50. Mu.m, 60. Mu.m, 80. Mu.m, 100. Mu.m, 120. Mu.m, 140. Mu.m, 160. Mu.m, 180. Mu.m, etc.

In a second aspect, the present invention provides a method for producing a hollow fiber according to the first aspect, the method comprising the steps of;

mixing the nano material with an orientation auxiliary agent to obtain spinning solution; and spinning or 3D printing the spinning solution to obtain the hollow fiber.

Preferably, the nanomaterial is present in the form of a nanomaterial dispersion.

In the invention, the orientation auxiliary agent can also adjust the viscosity of the nano material dispersion liquid, and is more beneficial to spinning.

In the invention, the preparation method of the nanomaterial dispersion liquid comprises the following steps: and mixing and dispersing the nano material, a dispersing agent and a solvent to obtain the nano material dispersion liquid.

Preferably, the dispersing agent comprises at least one of sodium cholate, sodium dodecyl sulfonate or polyvinylpyrrolidone.

Preferably, the method of mixed dispersion includes at least one of ultrasonic dispersion, cell disruption, or high pressure homogenization.

Preferably, the nanomaterial dispersion may have a mass percentage of 0.1 to 5%, for example, 0.2%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.4%, 3.8%, 4%, 4.2%, 4.6%, 4.8%, etc.

Preferably, the spinning comprises coaxial spinning.

Preferably, the specific steps of coaxial spinning include: mixing the nano material with an orientation auxiliary agent to obtain spinning solution; extruding the spinning solution and the internal coagulation bath, and externally coagulating to obtain the hollow fiber.

Preferably, the extrusion apparatus comprises a coaxial syringe pump.

Preferably, the flow rate of the outer hole of the coaxial injection pump is 35-45 mL/h, and for example, 36mL/h, 37mL/h, 38mL/h, 39mL/h, 40mL/h, 41mL/h, 42mL/h, 43mL/h, 44mL/h and the like can be used.

Preferably, the flow rate of the inner hole of the coaxial injection pump is 30-40 mL/h, and can be 31mL/h, 32mL/h, 33mL/h, 34mL/h, 35mL/h, 36mL/h, 37mL/h, 38mL/h, 39mL/h and the like.

In the invention, the flow rate of the outer hole of the coaxial injection pump refers to the flow rate of the spinning solution, and the flow rate of the inner hole refers to the flow rate of the inner coagulating bath; the flow velocity of the outer holes and the flow velocity of the inner holes are in a specific range, and the prepared hollow fiber is more suitable for being used as a resin reinforcement, so that the mechanical property of the composite material is improved.

Preferably, the inner coagulation bath and the outer coagulation bath each independently comprise at least one of water, methanol, ethanol, isopropanol, or acetone.

Preferably, the inner coagulation bath and the outer coagulation bath each independently include a mixed solvent of water and an organic solvent.

Preferably, the volume ratio of water to organic solvent is (0.1-1): 1, and may be, for example, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, etc.

Preferably, the speed of the external coagulation bath is 1200-1800 m/h, and can be 1250m/h, 1300m/h, 1350m/h, 1400m/h, 1450m/h, 1500m/h, 1550m/h, 1600m/h, 1650m/h, 1700m/h, 1750m/h, etc.

In the present invention, the coagulation bath speed refers to the coagulation bath rotational speed.

Preferably, the solidification further comprises a step of rolling and/or drying.

Preferably, the speed of the winding is 1600-2000 m/h, for example 1650m/h, 1700m/h, 1750m/h, 1800m/h, 1850m/h, 1900m/h, 1950m/h, 1980m/h, etc.

Preferably, the drying temperature is 20 to 80 ℃, and may be 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃ or the like, for example.

In the invention, the drying temperature can realize the regulation and control of the thickness of the fiber wall and the diameter of the fiber.

In a third aspect, the present invention provides a nanocomposite comprising a matrix resin and a nanoreinforcement; the nanoreinforcement comprises hollow fibers as described in the first aspect.

Preferably, the matrix resin comprises a thermosetting resin and/or a thermoplastic resin.

Preferably, the mass percentage of the hollow fiber in the nanocomposite is 5-50%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, etc.

In the invention, the preparation method of the nanocomposite comprises the step of combining hollow fibers with resin by a dipping or vacuum infusion method to obtain the nanocomposite.

According to the invention, the hollow fiber obtained by adopting specific raw material proportion and process is used as a resin reinforcement, on one hand, resin can be infiltrated into both the outer surface and the inner surface of the hollow fiber, and the resin diffusion distance is reduced, so that the uniform mixing of the resin and the nano material is realized, and compared with the traditional solid fiber, the problems that the structure is uneven and the resin cannot enter the fiber core part due to the skin-core structure of the solid fiber are solved. On the other hand, the orientation degree of the nano material in the hollow fiber obtained by the invention is high, and the problems of direct dispersion, poor orientation of the nano material in the film and the traditional solid fiber are solved; meanwhile, the high degree of orientation can obtain high mechanical and electrical properties, so that the nano material content in the finally obtained nano composite material is high and can be uniformly dispersed, and the mechanical properties of the composite material are improved.

In the invention, when the nano material is a conductive material, the conductivity of the nano composite material is improved by adding the orientation auxiliary agent with a specific proportion.

The numerical ranges recited herein include not only the recited point values, but also any point values between the recited numerical ranges that are not recited, and are limited to, and for the sake of brevity, the invention is not intended to be exhaustive of the specific point values that the recited range includes.

Compared with the prior art, the invention has the beneficial effects that:

according to the hollow fiber provided by the invention, the orientation degree of the nano material in the fiber is improved by adding the orientation auxiliary agent with specific content, so that the hollow fiber with a hollow, porous and high-orientation structure is obtained, and the mechanical property and the electrical property of the hollow fiber are improved; the shape and the structure of the carbon nanotube hollow fiber are controllable, the continuous production can be realized, the application of the hollow fiber is expanded, the content of the nano material in the resin composite material is improved, the uniform dispersion of the nano material in the resin can be realized, and the mechanical property of the resin composite material is improved.

Drawings

Fig. 1 is a scanning electron microscope image of a hollow fiber according to embodiment 1 of the present invention.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

In the present invention, the raw materials of all examples and comparative examples are as follows, unless otherwise specified:

original carbon nanotubes: OCSiAl single-walled carbon nanotubes;

nanocellulose: nanocellulose of different diameter sizes can be prepared by the methods disclosed in the literature (Zhu, h.; zhu, s.; jia, z.; parvinian, s.; li, y.; vaaland, o.; hu, l.; li, t.; anomalous scaling law of strength and toughness of cellulose nanopaper, proc Natl Acad Sci U S A, 2015,112 (29), 8971-8976.);

original graphene oxide: ji Cang JCGO-1-50;

the carbon nanotubes with different lengths and the graphene oxide with different sheet diameters in the specific embodiment can be obtained by mechanically treating the original carbon nanotubes and the original graphene oxide by oxidation or ultrasonic treatment.

Example 1

The present example provides a hollow fiber whose raw material includes carbon nanotubes (length of 30 μm) and nanocellulose (diameter: 5 nm); the mass ratio of the carbon nano tube to the nano cellulose is 20:1.

The embodiment provides a preparation method of a hollow fiber, which specifically comprises the following steps:

(1) Uniformly mixing carbon nanotubes with sodium dodecyl sulfonate in water, and performing ultrasonic dispersion to prepare a carbon nanotube dispersion liquid (the mass percentage of the carbon nanotubes in the carbon nanotube dispersion liquid is 0.4%); adding nano cellulose into the carbon nano tube dispersion liquid to obtain a carbon nano tube spinning stock solution;

(2) Filling the carbon nanotube spinning solution obtained in the step (1) and an inner coagulation bath (water and ethanol mixed solution with the volume ratio of 0.5:1) into a coaxial injection pump, extruding the carbon nanotube spinning solution into an outer coagulation bath through the coaxial injection pump to form fibers, and then winding the fibers and drying the fibers at 60 ℃ to obtain the carbon nanotube hollow fibers; the flow rate of the outer hole of the coaxial injection pump is 40mL/h, and the flow rate of the inner hole is 35mL/h; the external coagulation bath is a mixed solution of ethanol and water, the mixing volume ratio is ethanol to water=1:0.2, the coagulation bath is a rotary coagulation bath, the speed of the coagulation bath is 1300m/h, and the winding speed is 1700m/h.

The morphology of the hollow fiber obtained in example 1 was characterized by using a scanning electron microscope (model: S-4800), and the result is shown in FIG. 1.

Example 2

The present example provides a hollow fiber whose raw material includes carbon nanotubes (length of 20 μm) and graphene oxide (sheet diameter of 0.5 μm); the mass ratio of the carbon nano tube to the graphene oxide is 12:1.

(1) Uniformly mixing carbon nanotubes with sodium dodecyl sulfonate in water, and performing ultrasonic dispersion to prepare a carbon nanotube dispersion liquid (the mass percentage of the carbon nanotubes in the carbon nanotube dispersion liquid is 1%); adding graphene oxide into the carbon nanotube dispersion liquid to obtain a carbon nanotube spinning stock solution;

(2) Filling the carbon nanotube spinning solution obtained in the step (1) and an inner coagulation bath (water and acetone mixed solution with the volume ratio of 0.8:1) into a coaxial injection pump, extruding the carbon nanotube spinning solution into an outer coagulation bath through the coaxial injection pump to form fibers, and then winding the fibers and drying the fibers at 60 ℃ to obtain the carbon nanotube hollow fibers; the flow rate of an outer hole of the coaxial injection pump is 35mL/h, and the flow rate of an inner hole of the coaxial injection pump is 30mL/h; the external coagulation bath is a mixed solution of isopropanol and water, the mixing volume ratio is isopropanol to water=1:0.1, the coagulation bath is a rotary coagulation bath, the speed of the coagulation bath is 1500m/h, and the winding speed is 1800m/h.

Example 3

The present example provides a hollow fiber, the raw material of which comprises carbon nanotubes (length of 50 μm) and graphene oxide (sheet diameter of 0.2 μm); the mass ratio of the carbon nano tube to the graphene oxide is 15:1.

This example provides a method for preparing hollow fibers, the specific steps of which are the same as those of example 1.

Example 4

The present example provides a hollow fiber, the raw material of which comprises carbon nanotubes (length 40 μm) and graphene oxide (sheet diameter 1 μm); the mass ratio of the carbon nano tube to the graphene oxide is 18:1.

Example 5

The embodiment provides a hollow fiber, wherein the raw materials of the hollow fiber comprise graphene oxide (original graphene oxide) and nanocellulose (diameter is 10 nm); the mass ratio of the graphene oxide to the nanocellulose is 5:1.

Example 6

This example provides a hollow fiber which differs from example 2 only in that the graphene oxide has a sheet diameter of 2 μm, and the other raw material amounts, preparation methods and parameters are the same as those of example 2.

Example 7

This example provides a hollow fiber, which differs from example 2 only in that the graphene oxide has a sheet diameter of 50nm, and the other raw material amounts, preparation methods and parameters are the same as example 2.

Example 8

This example provides a hollow fiber which differs from example 1 only in that the diameter of the nanocellulose is 20nm, and the other raw material amounts, preparation methods and parameters are the same as example 1.

Example 9

This example provides a hollow fiber which differs from example 1 only in that the diameter of the nanocellulose is 1nm, and the other raw material amounts, preparation methods and parameters are the same as example 1.

Example 10

This example provides a hollow fiber which differs from example 2 only in that in the preparation method, the flow rate of the outer hole of the coaxial syringe pump of step (2) is 30mL/h, the flow rate of the inner hole is 45mL/h, and the amount of other raw materials, preparation method and parameters are the same as those of example 2.

Example 11

This example provides a hollow fiber which differs from example 2 only in that in the preparation method, the flow rate of the outer hole of the coaxial syringe pump of step (2) is 50mL/h, the flow rate of the inner hole is 25mL/h, and the amount of other raw materials, preparation method and parameters are the same as those of example 2.

Comparative example 1

This comparative example provides a hollow fiber differing from example 2 only in that the mass ratio of carbon nanotubes to graphene oxide is 3:1, and other raw material amounts, preparation methods and parameters are the same as example 2.

Comparative example 2

This comparative example provides a hollow fiber differing from example 2 only in that the mass ratio of carbon nanotubes to graphene oxide is 25:1, and other raw material amounts, preparation methods and parameters are the same as example 2.

Comparative example 3

This comparative example provides a hollow fiber differing from example 2 only in that graphene oxide is not contained in the raw material of the carbon nanotube hollow fiber, and the other raw material amounts, preparation methods and parameters are the same as those of example 2.

Comparative example 4

This comparative example provides a solid fiber which differs from example 2 only in that in the preparation method, a single-shaft injection pump is used in step (2), the extrusion flow rate is 5mL/h, and the other raw material amounts, steps and parameters are the same as in example 2.

Application example 1

A nanocomposite comprising, in mass percent, 92% epoxy (hounsman CY5948/HY 925-1) and 8% hollow fibers (example 1); the preparation method of the nanocomposite comprises the following steps: and (3) dissolving epoxy resin in acetone, wherein the mass fraction is 6%, immersing the dried hollow fiber in an acetone solution of the epoxy resin, and carrying out hot press curing at 100 ℃ to obtain the nanocomposite.

Application example 2

A nanocomposite comprising, in mass percent, 90% epoxy (hounsman CY5948/HY 925-1) and 10% hollow fibers (example 2); the preparation method of the nanocomposite comprises the following steps: and (3) dissolving epoxy resin in acetone, wherein the mass fraction is 6%, immersing the dried hollow fiber in an acetone solution of the epoxy resin, and carrying out hot press curing at 100 ℃ to obtain the nanocomposite.

Application examples 3 to 11

Application examples 3 to 11 provide nanocomposite materials differing from application example 1 only in that the hollow fibers provided in examples 3 to 11 were selected, respectively, and other raw materials, amounts, and preparation methods were the same as those of application example 1.

Comparative application examples 1 to 3

Comparative examples 1 to 3 provided nanocomposite materials differing from example 1 only in that the hollow fibers provided in comparative examples 1 to 3 were selected, respectively, and other raw materials, amounts, and preparation methods were the same as those of example 1.

Comparative application example 4

Comparative application example 4 provides a nanocomposite material differing from application example 1 only in that the fibers are solid fibers provided in comparative example 4, and other raw materials, amounts and preparation methods are the same as those of application example 1.

Performance testing

(1) Tensile strength: 5 samples with the same length (1 cm) are tested by an instron3365 mechanical stretcher (U.S.) and the load data are recorded, then the cross section of the original fiber is observed by SEM (S-4800, hitachi, japan), and the mechanical tensile strength data are obtained by calculation of a strength formula; tensile strength = axial tension/cross-sectional area of the material test piece;

(2) Conductivity: each sample (5 samples are manufactured to be averaged) is manufactured into a sample to be tested with the same length (1 m), the resistance of the sample is tested through an instrument KEITHLEY INSTRUMENTS 28775AURORA RD.CLEVELAND,OHIO 44139, and the conductivity data of the fiber is obtained through calculation according to the conductivity calculation formula through the section data of the SEM; conductivity = length of sample to be measured/(resistance x cross-sectional area).

The specific test results are shown in table 1:

TABLE 1

	Tensile Strength (MPa)	Conductivity (S/m)/10 ⁴
			Application example 1	368	1.2
Application example 2	600	12
			Application example 3	450	10.2
Application example 4	410	8.5
			Application example 5	330	Non-conductive
Application example 6	320	6.5
			Application example 7	315	5.4
Application example 8	290	0.3
			Application example 9	280	0.7
Application example 10	260	3.5
			Application example 11	252	2.2
Comparative application example 1	330	7.5
			Comparative application example 2	288	6.4
Comparative application example 3	240	4.8
			Comparative application example 4	130	5.4

As can be seen from the table, the hollow fiber provided by the invention is beneficial to improving the orientation degree of the nano material in the fiber by adding the specific content of the orientation auxiliary agent, and the hollow fiber with a hollow, porous and high-orientation structure is obtained, so that the resin composite material comprising the hollow fiber has excellent mechanical property and electric property. As is clear from application examples 1 to 5, the nanocomposite material comprising the hollow fiber has a tensile strength of 330 to 600MPa and an electrical conductivity of (0 to 12). Times.10 ⁴ 。

As is clear from comparison of application example 2 with application examples 6 and 7, the sheet diameter of the orientation agent graphene oxide is not within a specific range, and the orientation of the carbon nanotubes in the fiber is poor; as is clear from comparison of application example 1 with application examples 8 and 9, the sheet diameter of the nanocellulose is not within a specific range, the orientation of carbon nanotubes in the fiber is poor, and the mechanical properties are poor; as is clear from the comparison of application examples 2 and 10 to 11, the flow rate of the inner and outer holes of the coaxial syringe pump in the preparation method is not within a specific range, and the hollow fiber shape is difficult to maintain, collapse or has no hollow structure.

As is clear from the comparison of application example 2 and comparative application examples 1 to 3, the hollow fiber has no orientation aid or the orientation aid is not specifically mixed with the nanomaterial, and the mechanical properties and electrical properties of the fiber are deteriorated.

As can be seen from application example 2 and comparative application example 4, the hollow fiber provided by the invention is used as a reinforcement of resin, and the improvement of the resin performance is superior to that of solid fiber.

In summary, according to the hollow fiber provided by the invention, the orientation auxiliary agent is added, and a specific preparation method is adopted, so that the nano material in the fiber is highly oriented, and the hollow and porous fiber with controllable structure is obtained, and further, the hollow fiber is compounded with resin through methods such as dipping or vacuum infusion, so that the nano material content in the resin composite material is high and uniformly dispersed, and the mechanical property of the composite material are improved; and the preparation process of the hollow fiber is simple and can be used for continuous production.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims

1. A hollow fiber, characterized in that the raw materials of the hollow fiber comprise nano materials and orientation aids;

the mass ratio of the nano material to the orientation auxiliary agent is (5-20): 1.

2. The hollow fiber of claim 1, wherein the nanomaterial comprises at least one of carbon nanotubes, graphene oxide, cellulose, or boron nitride;

preferably, the length of the carbon nanotubes is 10 to 200 μm, more preferably 20 to 50 μm;

preferably, the graphene and graphene oxide each independently have a sheet diameter of 0.5 to 20 μm, and more preferably 5 to 15 μm.

3. The hollow fiber according to claim 2, wherein the cellulose has a diameter of 10 to 100nm;

4. A hollow fiber according to any one of claims 1 to 3, wherein the orientation aid comprises at least one of graphene oxide and nanocellulose.

5. The hollow fiber according to claim 4, wherein the graphene oxide in the orientation aid has a sheet diameter of 0.1 to 1 μm;

preferably, the diameter of the nanocellulose in the orientation aid is 2-10 nm.

6. The hollow fiber according to any one of claims 1 to 5, wherein the length of the hollow fiber is not less than 10cm;

preferably, the hollow fibers have a wall thickness of 2 to 100 μm.

7. A method of producing a hollow fiber according to any one of claims 1 to 6, characterized in that the method comprises the steps of;

8. The method of claim 7, wherein the nanomaterial is in the form of a nanomaterial dispersion;

preferably, the mass percentage of the nano material in the nano material dispersion liquid is 0.1-5%;

preferably, the spinning comprises coaxial spinning.

9. A nanocomposite, characterized in that the nanocomposite comprises a matrix resin and a nanoreinforcement;

the nanoreinforcement comprises the hollow fiber of any one of claims 1 to 6.

10. The composite material of claim 9, wherein the matrix resin comprises a thermosetting resin and/or a thermoplastic resin;

preferably, the mass percentage of the nano reinforcing body in the composite material is 5-50%.