CN115928241B

CN115928241B - Green structural color fiber containing graphene and polyacrylonitrile and preparation method thereof

Info

Publication number: CN115928241B
Application number: CN202210242976.4A
Authority: CN
Inventors: 李昕; 蒋鸣桃; 庞雅莉; 周一帆; 关芳兰; 龚䶮
Original assignee: Beijing Institute Fashion Technology
Current assignee: Beijing Institute Fashion Technology
Priority date: 2022-03-11
Filing date: 2022-03-11
Publication date: 2024-06-07
Anticipated expiration: 2042-03-11
Also published as: CN115928241A

Abstract

The invention belongs to the technical field of structural color fibers, and provides a green structural color fiber containing graphene and polyacrylonitrile and a preparation method thereof, wherein the preparation method comprises the following steps: mixing sodium thiocyanate with water to obtain sodium thiocyanate aqueous solution; mixing and stirring part of sodium thiocyanate aqueous solution, polyacrylonitrile and water to obtain swelling solution containing polyacrylonitrile; mixing the residual sodium thiocyanate aqueous solution with the swelling solution to obtain a mixed solution, and mixing the mixed solution with graphene oxide to obtain a spinning solution; and carrying out wet spinning on the spinning solution to obtain the green structural color fiber containing graphene and polyacrylonitrile. The fiber prepared by the invention is of a long-range disordered short-range ordered three-dimensional network structure, has bright green luster, stable color, uniform fiber thickness and diameter of 15-20 mu m, can be processed by subsequent twisting into yarns and the like, and has the potential of large-scale industrial production.

Description

Green structural color fiber containing graphene and polyacrylonitrile and preparation method thereof

Technical Field

The invention relates to the technical field of structural color fibers, in particular to a green structural color fiber containing graphene and polyacrylonitrile and a preparation method thereof.

Background

The acrylic fiber is a commodity name of polyacrylonitrile fiber, and the acrylic fiber is one of three synthetic fibers, and is a civil chemical fiber with wide application. The acrylic fiber has the advantages of softness, bulkiness, bright color, light resistance, bacteria resistance, worm damage resistance and the like, can be purely spun or blended with natural fiber according to the requirements of different purposes, is widely used in the fields of clothing, decoration, industry and the like, and is one of the largest acrylic industrial production centers in China. However, the acrylic fiber has serious electrostatic phenomenon due to hydrophobicity and insulativity, and the addition of the graphene is beneficial to improving the antistatic performance of the acrylic fiber.

The arrangement mode of carbon atoms of graphene and graphite is the same, bonds are formed by sp ² hybridized orbits, and the graphene has the following structural characteristics: 3 electrons in 4 electrons of each carbon atom form sp ² bonds, the rest electron is on a pz orbit, pi bonds are formed in the direction perpendicular to the plane of the pz orbit, and the pi bonds are in a half-filled state. The coordination number of carbon atoms of the graphene is 3, the covalent bond length between every two carbon atoms is about 0.142nm, and the bond angle is 120 degrees, so that a six-membered ring planar structure is formed. Graphene Oxide (GO) is exfoliated from graphite oxide. The graphene oxide can still be a monoatomic layer, and the particle size can reach about 10 mu m. The oxidized graphene has carboxyl, hydroxyl, aldehyde ketone and other functional groups, and has a more complex structure than single graphene.

The graphene oxide sheet contains any position of oxygen-containing groups such as hydroxyl, epoxy and the like, and the edge of the graphene oxide sheet is carboxyl and carbonyl. The graphene oxide has the advantages that the graphene oxide has the oxygen-containing functional groups on the surface, so that the graphene oxide has the surface activity, and compared with graphene, the graphene oxide has larger lamellar spacing and specific surface area, and the oxygen-containing functional groups have the hydrophilicity and adsorption capacity. The good hydrophilicity of GO makes it well dispersible in water, so it can be uniformly mixed with a water-based PAN solution.

The structural difference between GO and graphene is that many oxygen-containing functional groups attached to the carbon plane make it more structurally defective than graphene, without the complete structural integrity of graphene, resulting in its performance being affected. Reduction of GO to graphene is thus very valuable, with the aim of achieving two goals: removing oxygen-containing functional groups and recovering structural defects. There are many methods for reducing graphene oxide: thermal reduction, chemical reduction, microwave and photo-reduction, photo-catalyst reduction, and the like.

The photonic crystal optically follows the bragg diffraction law nλ= dsin θ, from which it is known that the diffraction wavelength is related to the lattice spacing d, the refractive index n of the material and the angle of incidence θ of light. From the material structure, the photonic crystal has a periodic structure similar to that of a crystal, and light with a certain frequency is strongly scattered in the periodic dielectric structure and forms a photonic band gap after multiple interference. The fundamental characteristic of the photonic crystal is that the photonic crystal has a photonic band gap, electromagnetic waves falling in the band gap are forbidden in any propagation direction, and the change of the dielectric refractive index and the space periodic structure can lead to the change of the photonic band gap. In nature, there are many photonic crystal fiber structures such as the velvet of the petal of the chenopodium album, the hair of the silver ant of the saharan desert, the fruit epidermis cells showing a bright blue-green color and the animal feathers having a bright photonic crystal structure color, such as the feathers of peacock feathers, green duck feathers, black-mouth magpie feathers and the like, the wings of the butterfly, opal and the like, which reflect various gorgeous colors in sunlight, which are not obtained by adding dyes but are generated by periodic arrangement of the nano structures on the surface of the material, and are thus called photonic crystals. The photonic crystal is firstly proposed in the optical field, and the unique structure of the photonic crystal has the effects of reflecting, refracting and the like on light, so that the photonic crystal has colorful and bright color, does not need dyeing and never fades, has small requirements on water and heat, is environment-friendly and is favorable for sustainable development.

At present, the industrialized methods for producing the structural color fiber are few, and a multilayer film interferometry method, a self-assembly method, an electrophoretic deposition method, a hot stamping method and a micro extrusion method are adopted. Multilayer film interferometry: for example, morphotex structural color fiber of Japanese Di company adopts a multi-layer hollow structure, 31 layers of nylon 6 and 30 layers of polyester are laminated in a staggered manner, the thickness of each layer of polymer is 70-90 nm, and the structural color fiber is obtained by precisely controlling the thickness of the polymer. However, the production cost is high, the preparation process is complex, the large-scale industrial production is difficult, the color is not as bright as expected, and the market is small. The self-assembly method is also one of methods for preparing structural color fibers, but it is necessary to assemble and arrange microspheres such as Polystyrene (PS) on the surface of the fibers to generate structural color, and the preparation time of the method is too long and mass preparation cannot be achieved. The structural color produced by the self-assembly method depends on the microspheres on the surface, and the size and the attaching uniformity of the microspheres directly influence the color formation of the fiber. The process of depositing colloidal particles on a matrix material is called electrophoretic deposition, which can greatly reduce the test time compared with the conventional self-assembly method, and the electrophoresis method has short structural color fiber preparation time, but requires that the fiber must be conductive and is not suitable for common natural or polymer fibers. In addition to this, hot embossing and micro-extrusion methods have the main problems of inadequate color development and too coarse fibers to be useful in the subsequent weaving process.

Therefore, the preparation method for forming the fiber composed of the photonic crystal structure by introducing the graphene is researched, so that the fiber has the characteristics of permanent color fading, high saturation and high brightness, does not need chemical dyeing, is green and environment-friendly, effectively improves the dyeing problem and the static problem of the fiber, and has important significance for development of textile industry.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a green structural color fiber containing graphene and polyacrylonitrile and a preparation method thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides a preparation method of a green structural color fiber containing graphene and polyacrylonitrile, which comprises the following steps:

1) Mixing sodium thiocyanate with water to obtain sodium thiocyanate aqueous solution;

2) Mixing and stirring part of sodium thiocyanate aqueous solution, polyacrylonitrile and water to obtain swelling solution containing polyacrylonitrile;

3) Mixing the residual sodium thiocyanate aqueous solution with the swelling solution to obtain a mixed solution, and mixing the mixed solution with graphene oxide to obtain a spinning solution;

4) And carrying out wet spinning on the spinning solution to obtain the green structural color fiber containing graphene and polyacrylonitrile.

Preferably, in the aqueous solution of sodium thiocyanate in the step 1), the mass concentration of sodium thiocyanate is 56-60%.

Preferably, the mass ratio of the part of the sodium thiocyanate aqueous solution in the step 2) to the sodium thiocyanate aqueous solution in the step 1) is 28-30: 67-71; the mass ratio of the partial sodium thiocyanate aqueous solution to the polyacrylonitrile to the water is 28-30: 10 to 12:18 to 20.

Preferably, the stirring time in the step 2) is 17-25 min; the mixing is that after the partial sodium thiocyanate aqueous solution and water are mixed, the mixture is mixed with polyacrylonitrile.

Preferably, the temperature of the mixture of the residual sodium thiocyanate aqueous solution and the swelling liquid in the step 3) is 55-75 ℃ and the time is 0.5-1.5 h.

Preferably, the mass ratio of the graphene oxide in the step 3) to the polyacrylonitrile in the step 2) is 0.6-1.5: 8 to 14.

Preferably, in the wet spinning process in the step 4), the pre-stretching water bath temperature is 45-60 ℃, the preheating tank temperature is 80-95 ℃, the hot stretching temperature is 85-100 ℃, the drying temperature is 110-130 ℃, the rotating speed of a metering pump is 15-25 r/min, the line speed of a driving roller is 0.5-1.5 m/min, the line speed V1 of the pre-stretching roller is 0.6-1.5 m/min, the line speed V2 of the pre-stretching roller is 1.5-2.5 m/min, the line speed V1 of the hot stretching roller is 1.5-2.5 m/min, the line speed V2 of the filament collecting roller is 2.5-3.5 m/min.

Preferably, the wet spinning device in the step 4) comprises a coagulating bath I, a coagulating bath II, a pre-drawing tank, a preheating tank, a hot drawing tank, a drying box and a filament receiving machine.

The invention also provides the green structural color fiber containing graphene and polyacrylonitrile, which is prepared by the preparation method.

The beneficial effects of the invention include:

The fiber prepared by the method is of a long-range disordered short-range ordered three-dimensional network structure, the three-dimensional network structure carried by the fiber generates structural color, and the prepared fiber has bright green color, luster and stable color.

The invention adopts the preparation methods of thermal reduction method and chemical reduction method, the wet spinning process has low production cost and simple process, and the preparation process does not need to add pellets. The invention uses the customized spinneret, and controls a certain pump supply and drive roll speed, so that the fiber can reach 15-20 mu m, the fiber thickness is uniform, the subsequent processing such as twisting into yarn is facilitated, and the invention has the potential of large-scale industrial production.

Drawings

FIG. 1 is a schematic diagram of the device connection for wet spinning according to the present invention;

FIG. 2 is a physical view of the green structural color fiber of example 1;

FIG. 3 is a microscopic view of a single green structural color fiber of example 1;

FIG. 4 is an SEM image of green structural color fibers of example 1;

FIG. 5 is a chromatogram of the green structural color fiber of example 1, wherein Y is 36.83, x is 0.3518, and Y is 0.3903 in the Yxy coordinates;

FIG. 6 is an electron image of the green structural color fiber of example 1 and an electron microscope EDS point energy spectrum corresponding to the selected position;

FIG. 7 is a physical view of the green structural color fiber of example 4;

FIG. 8 is a physical view of the green structural color fiber of example 5;

FIG. 9 is a physical view of the structural color fiber of comparative example 1.

Detailed Description

In the aqueous solution of sodium thiocyanate in the step 1) of the present invention, the mass concentration of sodium thiocyanate is preferably 56 to 60%, more preferably 57 to 59%, and still more preferably 58%.

The mass ratio of the part of sodium thiocyanate aqueous solution in the step 2) to the sodium thiocyanate aqueous solution in the step 1) is preferably 28-30: 67 to 71, more preferably 28.5 to 29.5:68 to 70, more preferably 29:69; the mass ratio of the partial sodium thiocyanate aqueous solution, the polyacrylonitrile and the water is preferably 28-30: 10 to 12:18 to 20, more preferably 28.5 to 29.5:10.5 to 11.5:18.5 to 19.5, more preferably 29:11:19; the polyacrylonitrile is preferably polyacrylonitrile powder.

The stirring time in the step 2) is preferably 17 to 25min, more preferably 18 to 23min, and even more preferably 20 to 21min; the mixing is preferably mixing part of sodium thiocyanate aqueous solution and water, and then mixing with polyacrylonitrile; and (3) after mixing part of sodium thiocyanate aqueous solution and water, cooling the obtained mixed solution to room temperature, slowly adding polyacrylonitrile while stirring to obtain milk-like milky mixed solution, and stirring the milky mixed solution to obtain swelling solution containing polyacrylonitrile.

The temperature of mixing the residual sodium thiocyanate aqueous solution and the swelling liquid in the step 3) is preferably 55-75 ℃, more preferably 62-68 ℃, and even more preferably 65-66 ℃; the mixing time is preferably 0.5 to 1.5 hours, more preferably 0.75 to 1.25 hours, and still more preferably 1 hour.

In the mixing process of the step 3), the mixed solution of the residual sodium thiocyanate aqueous solution and the swelling solution is gradually thickened from milky, is gradually clarified and transparent and has transparent yellow color, so that the mixed solution is obtained, a small amount of the mixed solution is dipped by a glass rod, and the mixed solution is slowly stretched and has the wire drawing phenomenon.

Before the mixed solution and the graphene oxide are mixed in the step 3), the mixed solution is cooled to 18-25 ℃.

In the preparation method, the graphene oxide is reduced by adopting a chemical reduction method and a thermal reduction method at the same time; the chemical reduction of the graphene oxide occurs in the mixing and contact process with sodium thiocyanate, including the mixing with sodium thiocyanate in the preparation process of spinning solution, and the contact with sodium thiocyanate in the wet spinning primary fiber coagulation bath; thermal reduction of graphene oxide occurs during the fiber drying process.

The mass ratio of the graphene oxide in the step 3) to the polyacrylonitrile in the step 2) is preferably 0.6-1.5: 8 to 14, more preferably 0.9 to 1.1:10 to 12, more preferably 1:11.

In the spinning solution in the step 3), the total solid content of polyacrylonitrile and graphene oxide is preferably 10-14%, more preferably 11-13%, and even more preferably 12%; the mass concentration of sodium thiocyanate is preferably 38 to 42%, more preferably 39 to 41%, and even more preferably 40%.

In the wet spinning process in the step 4), the temperature of the pre-stretching water bath is preferably 45-60 ℃, more preferably 50-55 ℃, and even more preferably 52-53 ℃; the preheating tank temperature is preferably 80 to 95 ℃, more preferably 85 to 90 ℃, and even more preferably 87 to 88 ℃; the hot drawing temperature is preferably 85 to 100 ℃, more preferably 92 to 97 ℃, still more preferably 94 to 96 ℃; the drying temperature is preferably 110 to 130 ℃, more preferably 115 to 125 ℃, and even more preferably 119 to 121 ℃.

In the wet spinning process in the step 4), the rotating speed of the metering pump is preferably 15-25 r/min, more preferably 18-22 r/min, and even more preferably 19-20 r/min; the line speed of the drive roll is preferably 0.5 to 1.5m/min, more preferably 0.9 to 1.1m/min, and still more preferably 1m/min; the pre-draft roller line speed V1 is preferably 0.6 to 1.5m/min, more preferably 0.9 to 1.1m/min, and still more preferably 1m/min; v2 is preferably 1.5 to 2.5m/min, more preferably 1.9 to 2.1m/min, and still more preferably 2m/min; the heat-drawing roll line speed V1 is preferably 1.5 to 2.5m/min, more preferably 1.9 to 2.1m/min, and still more preferably 2m/min; v2 is preferably 2.5 to 3.5m/min, more preferably 2.9 to 3.1m/min, and still more preferably 3m/min; the take-up roll line speed is preferably 2.5 to 3.5m/min, more preferably 2.9 to 3.1m/min, and still more preferably 3m/min.

In the wet spinning process of step 4) of the present invention, the mass concentration of coagulation bath I and the mass concentration of coagulation bath II are independently preferably 8 to 12%, more preferably 9 to 11%, and still more preferably 10%.

The wet spinning device in the step 4) comprises a coagulating bath I, a coagulating bath II, a pre-drawing tank, a preheating tank, a hot drawing tank, a drying box and a filament receiving machine; the device connection schematic diagram of the wet spinning is shown in figure 1; as can be seen from fig. 1, there are two parallel rollers in the pre-drawing tank, the linear velocity V1 corresponds to the left Bian Yuangun (near the coagulation bath II) in the pre-drawing tank, and V2 corresponds to the right roller in the pre-drawing tank; the hot drawing roller has two parallel rollers, with the linear speed V1 corresponding to the speed of the right roller (near the preheating tank) in the hot drawing tank and V2 corresponding to the left roller in the hot drawing tank.

In the preparation method of the invention, the number of rotating rolls in the wet spinning device is set according to the actual situation, and fig. 1 is only a schematic device.

The wet spinning process of the invention comprises the following steps: placing spinning solution into a charging bucket, standing, defoaming, preserving heat for more than 8 hours, pouring sodium thiocyanate aqueous solution (with the mass concentration of 10%) into a coagulating bath I and a coagulating bath II, placing steel ice particles to reduce the temperature of the two baths, adding deionized water into a pre-drawing tank, a preheating tank and a hot drawing tank, heating the pre-drawing tank, the preheating tank and the hot drawing tank to 50-55 ℃, 85-90 ℃, 90-99 ℃ respectively, and heating a heating oven to 115-125 ℃. Starting a metering pump to filter the feed liquid through a candle filter, extruding and defoamating the feed liquid in a spinneret for 20min, starting each rotating roller and a wire collecting machine to wind wires, and finally adjusting the roller speed of each rotating roller to control the proper draft ratio.

In the wet spinning, the operation sequence of the spinning machine is that a metering pump is installed, a charging bucket is assembled, spinning solution is added, coagulating bath and water bath are poured, parameters of a control panel are set, a metering pump, a coagulating bath guide roller, a pre-drawing I, a pre-drawing II, a hot drawing I, a hot drawing II and a motor switch for filament collection are turned on, and a pre-drawing groove, a preheating groove, a hot drawing groove and a drying heating switch are turned on.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

400G of sodium thiocyanate solid was added to 290g of deionized water, and heated with stirring until sodium thiocyanate was completely dissolved, yielding 690g of a homogeneous aqueous solution of sodium thiocyanate with a mass concentration of 58%. After the aqueous sodium thiocyanate solution had cooled down to a stable state, it was divided into 290g (for the swelling process) and 400g (for the dissolution process).

290G of sodium thiocyanate aqueous solution and 190g of deionized water are mixed, the temperature is controlled to 25 ℃, and 110g of polyacrylonitrile powder is slowly added while stirring, so that milk-like milky mixed solution is obtained. The beaker containing the solution is placed on a magnetic stirrer and stirred for 20min at 25 ℃ to enable the polyacrylonitrile powder to be fully swelled in the solution, thus obtaining swelling liquid.

400G of sodium thiocyanate aqueous solution is added into the swelling liquid, the temperature is gradually increased to 65 ℃ by stirring and heating, the temperature is kept for 1h at 65 ℃, the milky liquid is gradually thickened, is gradually clear and transparent and has transparent yellow color, a small amount of liquid is dipped by a glass rod for slow stretching at the moment, and the phenomenon of wiredrawing can be observed. And cooling the mixed solution to 25 ℃, adding 10g of graphene oxide (ground by an agate mortar), and uniformly stirring to obtain the spinning solution.

And (3) placing the spinning solution into a charging bucket, standing, defoaming and preserving heat for 9 hours, and then carrying out wet spinning, wherein in the wet spinning process, the total solid content of polyacrylonitrile and graphene oxide in the fixed spinning solution is 12%, the mass concentration of sodium thiocyanate is 40%, the mass concentration of sodium thiocyanate aqueous solutions in a coagulating bath I and a coagulating bath II are 10%, the coagulating bath temperature is 20 ℃, adding deionized water into a pre-drawing tank, a preheating tank and a hot drawing tank, the pre-drawing water bath temperature is 53 ℃, the water temperature in the preheating tank is 85 ℃, the water temperature in the hot drawing tank is 95 ℃, the drying temperature is 120 ℃, the rotating speed of a metering pump is 20r/min, the line speed of a driving roller is 1m/min, the line speed of a pre-drawing roller is 1m/min, the line speed of a V2 m/min, the line speed of a hot drawing roller is 2m/min, the line speed of a V2 is 3m/min, and the line speed of a filament collecting roller is 3m/min, thereby obtaining the green structural fiber containing the graphene and the polyacrylonitrile.

A physical diagram of the green structural color fiber of example 1 is shown in fig. 2; a microscopic image of a single green structural color fiber is shown in fig. 3. As can be seen from fig. 2 and 3, the fiber of this embodiment is a glossy green structural color fiber.

An SEM image of the green structural color fiber of example 1 is shown in fig. 4, and it can be seen from fig. 4 that the microstructure of the fiber surface is a long-range disordered short-range ordered, loose porous three-dimensional network structure.

The chromatogram of the green structural color fiber of example 1 is shown in fig. 5, in the Yxy coordinates, Y is 36.83, x is 0.3518, and Y is 0.3903, showing that the fiber has a glossy yellowish green color under irradiation of natural light, according to the display of the coordinates on the graph and the combined color of the appearance of the fiber.

An electron image of the green structural color fiber of embodiment 1 and an electron microscope EDS point energy scanning spectrum corresponding to the selected position are shown in fig. 6; the results of the elemental analysis of the spectra are shown in Table 1. From fig. 6 and table 1, it can be seen that the fiber has a main constituent element C, N, contains a small amount of O and a trace amount of S and Na, indicating that the fiber mass is relatively pure.

TABLE 1 elemental analysis results of Green structural chromatogram of example 1

Example 2

392G of sodium thiocyanate solid was added to 298g of deionized water, and heated with stirring until sodium thiocyanate was completely dissolved, yielding 690g of a homogeneous aqueous solution of sodium thiocyanate having a mass concentration of 56.8%. After the aqueous sodium thiocyanate solution had cooled down to a stable state, it was divided into 290g (for the swelling process) and 400g (for the dissolution process).

290G of sodium thiocyanate aqueous solution and 195g of deionized water were mixed, the temperature was controlled to 25 ℃, and 105g of polyacrylonitrile powder was slowly added while stirring, to obtain a milky white mixed solution resembling milk. The beaker containing the solution is placed on a magnetic stirrer and stirred for 20min at 25 ℃ to enable the polyacrylonitrile powder to be fully swelled in the solution, thus obtaining swelling liquid.

400G of sodium thiocyanate aqueous solution is added into the swelling liquid, the temperature is gradually increased to 62 ℃ by stirring and heating, the temperature is kept for 1.2h at 62 ℃, the milky liquid is gradually thickened, is gradually clear and transparent and has transparent yellow color, a small amount of liquid is dipped by a glass rod for slow stretching at the moment, and the phenomenon of wiredrawing can be observed. And cooling the mixed solution to 25 ℃, adding 9g of graphene oxide (ground by an agate mortar), and uniformly stirring to obtain the spinning solution.

And (3) placing the spinning solution into a charging bucket, standing, defoaming and preserving heat for 8 hours, and then carrying out wet spinning, wherein in the wet spinning process, the total solid content of polyacrylonitrile and graphene oxide in the fixed spinning solution is 11.4%, the mass concentration of sodium thiocyanate is 39.2%, the mass concentration of sodium thiocyanate aqueous solution in a coagulating bath I and a coagulating bath II is 10%, the coagulating bath temperature is 20 ℃, adding deionized water into a pre-drawing tank, a pre-heating tank and a hot-drawing tank, the pre-drawing water bath temperature is 52 ℃, the water temperature in the pre-heating tank is 88 ℃, the water temperature in the hot-drawing tank is 92 ℃, the drying temperature is 115 ℃, the rotating speed of a metering pump is 20r/min, the line speed of a driving roller is 0.9m/min, the line speed of the pre-drawing roller is 1m/min, the line speed of V2 is 1.9m/min, the line speed of the hot-drawing roller is 2.1m/min, and the line speed of the V2 is 3m/min, and the line speed of a wire-collecting roller is 3.1m/min, thereby obtaining the green structural fiber containing the graphene and the polyacrylonitrile.

Example 3

800G of sodium thiocyanate solid was added to 580g of deionized water, and stirred and heated until sodium thiocyanate was completely dissolved, resulting in 1380g of a uniform aqueous solution of sodium thiocyanate having a mass concentration of 58%. After the aqueous sodium thiocyanate solution had cooled down to a stable state, it was separated into 580g (for the swelling process) and 800g (for the dissolution process).

580G of sodium thiocyanate aqueous solution and 380g of deionized water are mixed, the temperature is controlled to 25 ℃, and then 220g of polyacrylonitrile powder is slowly added while stirring, so that milk-like milky mixed solution is obtained. The beaker containing the solution is placed on a magnetic stirrer and stirred for 20min at 25 ℃ to enable the polyacrylonitrile powder to be fully swelled in the solution, thus obtaining swelling liquid.

800G of sodium thiocyanate aqueous solution is added into the swelling solution, the temperature is gradually increased to 65 ℃ by stirring and heating, the temperature is kept for 1h at 65 ℃, the milky liquid is gradually thickened, is gradually clear and transparent and has transparent yellow color, a small amount of liquid is dipped by a glass rod for slow stretching at the moment, and the phenomenon of wiredrawing can be observed. And cooling the mixed solution to 25 ℃, adding 20g of graphene oxide (ground by an agate mortar), and uniformly stirring to obtain the spinning solution.

And (3) placing the spinning solution into a charging bucket, standing, defoaming and preserving heat for 9 hours, and then carrying out wet spinning, wherein in the wet spinning process, the total solid content of polyacrylonitrile and graphene oxide in the fixed spinning solution is 12%, the mass concentration of sodium thiocyanate is 40%, the mass concentration of sodium thiocyanate aqueous solutions in a coagulating bath I and a coagulating bath II are 10%, the coagulating bath temperature is 19.5 ℃, adding deionized water into a pre-drawing tank, a pre-heating tank and a hot-drawing tank, the pre-drawing water bath temperature is 53 ℃, the water temperature in the pre-heating tank is 85 ℃, the water temperature in the hot-drawing tank is 95 ℃, the drying temperature is 120 ℃, the rotating speed of a metering pump is 20r/min, the line speed of a driving roller is 1m/min, the line speed of a pre-drawing roller is 1m/min, the line speed of V2 is 2m/min, the line speed of a hot-drawing roller is 3m/min, and the line speed of a filament collecting roller is 3m/min, thereby obtaining the green structural color fiber containing graphene and polyacrylonitrile.

Example 4

The mass concentration of the aqueous sodium thiocyanate solution in the coagulation bath I and the coagulation bath II of example 1 was changed to 9%, the rotational speed of the metering pump was 18r/min, the line speed of the driving roll was 0.8m/min, the line speed of the pre-drawing roll was 0.9m/min, V2 was 1.8m/min, the line speed of the hot drawing roll was 1.9m/min, V2 was 2.9m/min, the line speed of the take-up roll was 2.8m/min, and the other conditions were the same as in example 1.

A physical diagram of the green structural color fiber of example 4 is shown in fig. 7.

Example 5

The mass concentrations of the aqueous solutions of sodium thiocyanate in the coagulation bath I and the coagulation bath II of example 1 were changed to 11%, the rotational speed of the metering pump was 23r/min, the line speed of the driving roll was 1.1m/min, the line speed of the pre-drawing roll was 1.2m/min, V2 was 2.2m/min, the line speed of the heat-drawing roll was 2.1m/min, V2 was 3.1m/min, the line speed of the take-up roll was 3.1m/min, and the other conditions were the same as in example 1.

A physical diagram of the green structural color fiber of example 5 is shown in fig. 8.

As can be seen from fig. 2 and fig. 7 to 8, when the graphene oxide content is fixed to 1%, the green depth of the fiber is different by changing the wet spinning process conditions such as the rotation speed of the metering pump, the concentration of the coagulation bath, the line speed of the driving roll, the line speed of the pre-drawing roll, the line speed of the hot drawing roll, the line speed of the filament collecting roll, etc., fig. 2 is bright and glossy green, fig. 7 is lighter green, and fig. 8 is darker green.

Comparative example 1

The mass of graphene oxide in example 1 was changed to 5g, 15g, 20g, 30g, 40g, and 50g, and the other conditions were the same as in example 1.

As shown in fig. 9, a physical diagram of the structural color fiber of comparative example 1 shows that the content of graphene oxide determines the type of fiber color when the wet spinning process conditions are unchanged in fig. 2 and 9. The color of the acrylic fiber is pure white when the graphene oxide is not added, the acrylic fiber added with 0.5% of the graphene oxide is off-white (figure 9), and the acrylic fiber added with 1% of the graphene oxide is green (figure 2). When the mass concentration of graphene oxide is higher than 1%, the fiber gradually tends to be black with the increase of the mass concentration of graphene oxide, and when the mass concentration of graphene oxide reaches 5% or more, the fiber cannot be molded.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims

1. The preparation method of the green structural color fiber containing graphene and polyacrylonitrile is characterized by comprising the following steps of:

4) Carrying out wet spinning on the spinning solution to obtain green structural color fibers containing graphene and polyacrylonitrile;

In the step 1), the mass concentration of sodium thiocyanate in the sodium thiocyanate aqueous solution is 56-60%;

The mass ratio of the part of sodium thiocyanate aqueous solution in the step 2) to the sodium thiocyanate aqueous solution in the step 1) is 28-30: 67-71; the mass ratio of the partial sodium thiocyanate aqueous solution to the polyacrylonitrile to the water is 28-30: 10-12: 18-20 parts of a base;

The stirring time in the step 2) is 17-25 min; the mixing is that after part of sodium thiocyanate aqueous solution and water are mixed, the mixture is mixed with polyacrylonitrile;

The mass ratio of the graphene oxide in the step 3) to the polyacrylonitrile in the step 2) is 1:11, fixing the total solid content of polyacrylonitrile and graphene oxide in the spinning solution to be 12%;

step 3), mixing the residual sodium thiocyanate aqueous solution and the swelling solution at a temperature of 55-75 ℃ for 0.5-1.5 h;

In the wet spinning process, the temperature of a pre-drawing water bath is 53-60 ℃, the temperature of a preheating tank is 85-95 ℃, the temperature of hot drawing is 95-100 ℃, the drying temperature is 120-130 ℃, the rotating speed of a metering pump is 18-23 r/min, the line speed of a driving roller is 0.8-1.1 m/min, the line speed V1 of the pre-drawing roller is 0.9-1.2 m/min, V2 is 1.8-2.2 m/min, the line speed V1 of the hot drawing roller is 1.9-2.1 m/min, V2 is 2.9-3.1 m/min, and the line speed of a filament collecting roller is 2.8-3.1 m/min;

The microstructure of the green structural color fiber is a three-dimensional network structure with long-range disordered short-range ordered, loose and porous.

2. The method according to claim 1, wherein the wet spinning apparatus of step 4) comprises coagulation bath I, coagulation bath II, pre-drawing tank, preheating tank, hot drawing tank, drying box, and filament take-up machine.

3. The green structural color fiber containing graphene and polyacrylonitrile prepared by the preparation method of claim 1 or 2.