CN109183170B

CN109183170B - Preparation method of cellulose graphene composite short fiber

Info

Publication number: CN109183170B
Application number: CN201811013278.7A
Authority: CN
Inventors: 俞啸华; 郭建雄
Original assignee: Longsi Shanghai New Material Technology Co ltd
Current assignee: Longsi Shanghai New Material Technology Co ltd
Priority date: 2018-08-31
Filing date: 2018-08-31
Publication date: 2020-12-08
Anticipated expiration: 2038-08-31
Also published as: CN109183170A

Abstract

The invention discloses a preparation method of cellulose graphene composite short fibers, which comprises the following steps: a) mixing a dispersing agent, graphene oxide and cellulose, and dissolving the mixture in an ionic liquid aqueous solution, wherein the addition amount of the graphene oxide is 0.1-0.3 wt% of the cellulose, so as to prepare a mixed spinning solution; b) filtering, spinning, solidifying, stretching, washing, bleaching, oiling, cutting and drying the obtained mixed spinning stock solution to obtain the cellulose graphene composite short fiber; the ionic liquid is obtained by mixing 1-butyl-3-methylimidazole chlorine salt, bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt and bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt. Experiments show that: the cellulose graphene composite short fiber prepared by the method has excellent mechanical property, antistatic property and stability, and is simple in preparation process, low in cost, environment-friendly and pollution-free.

Description

Preparation method of cellulose graphene composite short fiber

Technical Field

The invention relates to a preparation method of cellulose graphene composite short fibers, and belongs to the technical field of functional cellulose fibers.

Background

Cellulose is a polysaccharide which is widely distributed and has the largest content in the nature, accounts for more than 50 percent of the carbon content in the plant, and is one of the most abundant natural organic matters in the nature. The cellulose is mainly derived from plants, such as cotton, wood, cotton linter, wheat straw, reed, hemp, mulberry bark and the like, wherein the cellulose content of the cotton is close to 100 percent and is the natural purest cellulose source, and the cellulose accounts for 40 to 50 percent, 10 to 30 percent of hemicellulose and 20 to 30 percent of lignin in the common wood. As a degradable green biomaterial, natural fiber gradually plays an increasingly important role due to its superior properties of light weight, degradability, low price, high modulus, high strength and the like. Therefore, natural cellulose obtained from plants is dissolved to prepare regenerated fibers, so that the regeneration and functionalization of the cellulose are realized, and the method is an important way for effectively utilizing the cellulose.

Graphene is a novel carbon two-dimensional nanomaterial, has the characteristics of excellent high strength, electrical conductivity, thermal conductivity, light transmittance, flexibility and the like, and has wide application prospects in the fields of solar cells, sensors, nanoelectronics, high-performance nanoelectronic devices, composite materials, field emission materials, gas sensors, energy storage and the like. The graphene is added into the clothing fiber, so that the fabric has the functions of high electrical conductivity, high thermal conductivity, high antibacterial property, high antistatic property and the like, and therefore, the preparation of the functional composite fiber by compounding the graphene and the fiber is a research hotspot at present.

At present, there are reports related to the preparation of composite fibers by compounding cellulose fibers and graphene. At present, the preparation of the cellulose graphene composite fiber is mainly to adopt a post-finishing method, namely, the graphene is finished on the fiber by adopting methods such as dipping, padding, coating or spraying, and the like, so as to prepare the composite fiber, but the surface of the graphene is in an inert state, the interaction with other media is very weak, the agglomeration is very easy to occur, and the graphene is difficult to be uniformly dispersed in a polymer or a solution thereof, so that the problems that the distribution of the graphene on the surface of the fiber is uneven, and the bonding firmness of the graphene and the fiber is low exist.

Aiming at the problem that graphene is easy to agglomerate, graphene oxide is mainly adopted to replace graphene and fibers for compounding at present, namely graphene oxide dispersion liquid is prepared firstly, and then the graphene oxide dispersion liquid is finished on the surfaces of the fibers by methods such as dipping, padding, coating or spraying to form a graphene oxide coating, but the bonding force between the graphene oxide and the fibers is still weak, the graphene oxide coating on the surfaces of the fibers is easy to crack and peel off after the fibers are dried, in addition, the graphene oxide on the surfaces of the fibers is generally required to be subjected to reduction treatment in the preparation process of the composite fibers, the graphene oxide is reduced into graphene, and high-toxicity reducing agents such as hydrazine hydrate and the like are difficultly used in the reduction treatment process, so that the graphene oxide coating has great harm to the environment and the health of human bodies, and reducing agents are difficult to remove in post-treatment, and the performance of the fibers can be adversely affected. Although there are reports related to reduction treatment of graphene oxide by other methods, there still exist some defects, such as: in chinese patent CN201310616126.7, graphene oxide dispersion is coated on the surface of a cellulose fabric to form a graphene oxide coated cellulose fabric, and then graphene oxide on the surface of the cellulose fabric is completely reduced to obtain a conductive cellulose fabric.

Except for a post-finishing method, the current preparation method of cellulose graphene composite fiber which is commonly used is a mixed spinning method, namely, the graphene and a cellulose solution are directly mixed into a spinning solution and then are spun to prepare the composite fiber. For example: in chinese patents CN201510682674.9, CN201510682733.2, and CN201510682720.5, the graphene aqueous solution and wood pulp are respectively mixed and dissolved in methyl morpholine oxide, and after water powder is removed, spinning mucus is formed, and then the composite fiber is prepared by a spun-bond method, a dry-jet-wet spinning method, or a melt-blown method. Compared with a post-finishing method, the preparation method has the advantages that although the firmness is improved, the graphene agglomeration phenomenon still inevitably occurs, and the performance of the composite fiber is seriously influenced.

For the problem of graphene agglomeration, similar to the post-finishing method, graphene oxide is mainly used instead of graphene at present, for example: in the Chinese patent CN201210549357.6, a graphene oxide solution and a cellulose solution are mixed and then spun, and then reduction treatment is carried out to prepare a composite fiber; in chinese patent CN201410363321.8, graphene oxide and nano-cellulose dispersion are mixed to prepare a spinning solution, and then spun, and then reduced to prepare the composite fiber. Although the method avoids the problem of graphene agglomeration, the reduction treatment of graphene oxide by using a reducing agent has low treatment efficiency, the used reducing agent (such as hydrazine hydrate, hydroiodic acid and the like) is difficult to avoid great harm to the environment and human health, and the reducing agent is difficult to remove in the post-treatment process, so that the performance of the fiber is adversely affected.

In order to solve the problem of reducing agents, there are reports that graphene oxide is modified and the modified graphene oxide is compounded with cellulose to prepare composite fibers so as to avoid using a reducing agent, for example: the Chinese patent CN201710884919.5 microcapsule technology is used for treating the modified graphene oxide solution, the dispersibility of the modified graphene oxide is improved, and then the regenerated cellulose spinning process is adopted to prepare the composite fiber. However, the modification treatment of the microcapsules inevitably makes the preparation process of the composite fiber more complex and the production cost higher, and a large amount of alkaline reagents of the modification kit are used in the modification process, which causes certain pollution to the environment and is not suitable for industrial production.

In addition, due to the characteristics of the self-aggregation structure, namely, a large number of hydrogen bonds exist in molecules and between molecules, and the cellulose has high crystallinity, so that the cellulose is difficult to dissolve in conventional solvents (such as water and most organic solvents) and the graphene is also difficult to dissolve in water, so that the cellulose and the graphene are difficult to directly dissolve in the conventional solvents. This has led to the inevitable use of solvent systems such as strong bases, N-dimethylacetamide/lithium chloride (DMAc/LiCl), N-dimethylformamide/dinitrogen tetroxide (DMF/N2O4), N-methyl-N-oxymorpholine (NMMO), dimethylsulfoxide/tetrabutylammonium fluoride (DMSO/TBAF), molten salt hydrates (e.g., LiClO 4.3H 2O, liscn.2h 2O), and polluting organic solvents, both in the preparation of composite fibers by the post-conditioning method and the hybrid spinning method, for example: dissolving graphene and wood pulp in CN201510682674.9, CN201510682733.2 and CN201510682720.5 by using methylmorpholine oxide; dissolving regenerated cellulose pulp in CN201710884919.5 by using sodium hydroxide; in CN201810051706.9, a mixed solution of sodium hydroxide, urea and water is used for dissolving cellulose and graphene; therefore, the solvent systems used in the existing preparation method of the composite fiber have the defects of strong toxicity, high cost, difficult recycling of the solvent, instability in the using process and the like, and are not suitable for industrial production.

The ionic liquid is a salt existing in a liquid state at room temperature or near room temperature, has the liquidity of the liquid and the chemical activity of the salt, and has a plurality of unique properties, such as designable structure, wide liquid range, vapor pressure close to zero, non-flammability, high thermal stability and chemical stability, and the like. At present, ionic liquid has made many advances in the aspects of separation process, catalysis, organic synthesis, electrochemistry and the like, and is considered to be a novel environment-friendly green medium with wide application prospect in green synthesis and clean production.

Researches show that the ionic liquid can directly dissolve cellulose, and Chinese patents CN 200610078784.5, CN200680012598.X, CN200710085298.0, CN201310158819.6 and the like respectively disclose a method for dissolving cellulose by the ionic liquid, and related reports about preparing functional composite fibers by dissolving cellulose and other functional substances by the ionic liquid are also provided at present, for example, Chinese patent CN200510077288.3 discloses a method for preparing biological protein wool fibers by mixing and dissolving animal hair and cellulose raw materials by taking the ionic liquid as a solvent; chinese patent CN201510313099.5 discloses a method for preparing keratin composite fibers by dissolving keratin and cellulose with ionic liquid as a solvent; chinese patent CN201410186603.5 discloses a method for preparing flame retardant fiber by dissolving cellulose and flame retardant polymer with ionic liquid as solvent; chinese patent CN 201510152558.6 discloses a method for preparing functional graphene cellulose fibers by dissolving cellulose and graphene with ionic liquid as a solvent. However, when the ionic liquid (alkyl quaternary ammonium salt, alkyl imidazolium salt, alkyl pyrrolate salt and the like) is used for dissolving cellulose and functional substances in the preparation process of the functional fiber at present, the pure ionic liquid is adopted for dissolving, so that the prepared spinning solution has high viscosity and poor spinnability, has great influence on the pressure resistance and the drafting of a spinneret plate in the subsequent spinning process, and is not beneficial to the subsequent spinning; in addition, when the ionic liquid is used for dissolving cellulose, the dissolving time is long, and is usually 2-48 hours, even up to 120 hours; the dissolving temperature is higher, generally about 100 ℃, even up to 150 ℃, and the energy consumption is higher; as such, the preparation of functional fibers by using ionic liquids is still in the laboratory stage, and the industrial scale cannot be realized, which severely limits the application and development of functional fibers (including cellulose graphene composite fibers).

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a preparation method of cellulose graphene composite short fibers to promote industrial production of the cellulose graphene composite fibers.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of cellulose graphene composite short fibers comprises the following steps:

a) mixing a dispersing agent, graphene oxide and cellulose, and dissolving the mixture in an ionic liquid aqueous solution, wherein the addition amount of the graphene oxide is 0.1-0.3 wt% of the cellulose, so as to prepare a mixed spinning solution;

b) filtering, spinning, solidifying, stretching, washing, bleaching, oiling, cutting and drying the obtained mixed spinning stock solution to obtain the cellulose graphene composite short fiber;

wherein the ionic liquid is prepared from the following components:

1-butyl-3-methylimidazolium chloride salt: 100 parts by mass;

bis 1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt: 5-10 parts by mass;

bis 1, 4-bis [1- (3-methylimidazole) ] butyl diperchichloride: 10-20 parts by mass;

mixing to obtain; wherein:

the chemical structural formula of the bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt is as follows:

the chemical structural formula of the bi-1, 4-bis [1- (3-methylimidazole) ] butyl diperchichloride is as follows:

preferably, the mass fraction of the ionic liquid aqueous solution is 30-95%, and more preferably 60-95%.

Preferably, the dissolving temperature in the step a) is 50-110 ℃ (preferably 60-80 ℃), and the dissolving time is 10-45 minutes (preferably 15-30 minutes).

Preferably, the preparation of the ionic liquid comprises the following steps:

firstly, 1-butyl-3-methylimidazole chlorine salt, bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt and bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride perchlorate are uniformly mixed according to the proportion, and then the mixture is stirred and reacted for 5 to 25 hours at the temperature of 110 to 130 ℃.

Preferably, the preparation of the bis 1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt comprises the following steps: dropwise adding N-methylimidazole into 1, 4-dichlorobutane at the temperature of 65-85 ℃ under the protection of inert gas, and then carrying out reflux reaction for 12-72 hours.

More preferably, the molar ratio of 1, 4-dichlorobutane to N-methylimidazole is 1:1 to 1: 1.5.

As a further preferable mode, the inert gas is nitrogen or argon.

Preferably, the preparation of the bis 1, 4-bis [1- (3-methylimidazole) ] butyl diperchlor comprises the following steps:

firstly, dissolving the bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt and the lithium perchlorate in water, then stirring and reacting for 12-48 hours at the temperature of 75-85 ℃, then cooling to room temperature, and continuing stirring for 5-15 hours at room temperature.

In a further preferred embodiment, the molar ratio of the bis-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt to the lithium perchlorate is 1:1 to 1: 1.5.

Preferably, the cellulose is selected from any one of wood pulp, cotton pulp, bamboo pulp, mulberry bark pulp, rice pulp, reed pulp, bagasse pulp and hemp pulp, the cellulose content is more than or equal to 90 wt%, and the polymerization degree is more than or equal to 500 (preferably 500-700).

Preferably, the mass ratio of the total amount of the cellulose and the graphene oxide to the ionic liquid aqueous solution is 1: 5-1: 25.

Preferably, the dispersing agent is silicon oxide, and the addition amount of the dispersing agent is 0.3-1 wt% of the ionic liquid aqueous solution.

Preferably, in the step b), a dry-jet wet spinning process is adopted for spinning, the temperature of a spinning solution is 50-110 ℃ (preferably 60-80 ℃), and the spinning speed is 60-150 m/min.

The dry-jet wet spinning process is characterized in that spinning solution is extruded through a spinneret to form spinning trickle, and the spinning trickle is preliminarily formed in wet cold air. The wet cold air is air with the temperature of 5-25 ℃ and the relative humidity of 60-95%.

Preferably, in the step b), the coagulation bath adopted in the coagulation consists of ionic liquid and water, the temperature of the coagulation bath is 0-20 ℃ (preferably 5-15 ℃), and the mass percentage of the ionic liquid is 5-25%.

Preferably, in the step b), the cutting length is 35 to 105 mm.

Compared with the prior art, the invention has the following remarkable beneficial effects:

1) the invention relates to 1-butyl-3-methylimidazole chlorine salt and bi-1, 4-di [1- (3-methylimidazole)]Butyl dichloride salt and bis 1, 4-bis [1- (3-methylimidazole)]The preparation method comprises the steps of compounding butyl diperchichloronate to prepare a novel ionic liquid, dissolving a dispersing agent, graphene oxide and cellulose into an ionic liquid aqueous solution to prepare a spinning stock solution, and then filtering, spinning, solidifying, stretching, washing, bleaching, oiling, cutting and drying to prepare the cellulose graphene composite short fiber, wherein the specific resistance of the prepared cellulose graphene composite short fiber is 1.1-7.3 x 10⁵Omega.m, has excellent antistatic property, excellent antibacterial property, far infrared property and excellent comprehensive performance;

2) the co-dissolving symbiosis of the graphene oxide and the cellulose is realized, the graphene oxide is uniformly dispersed in the spinning solution, the agglomeration phenomenon is avoided, the bonding firmness between the graphene oxide and the fiber in the composite fiber is good, various performances of the composite fiber are basically unchanged after multiple times of washing and printing and dyeing, the stability is excellent, particularly, the graphene oxide does not need to be subjected to reduction treatment in the preparation process, the operation is simple, and the composite fiber is clean and environment-friendly;

3) the method adopts the ionic liquid aqueous solution to dissolve cellulose and graphene oxide to prepare the spinning solution, the prepared spinning solution is low in viscosity, is beneficial to spinning, and can not cause loss to fibrous characteristics of raw materials in subsequent processes, so that the breaking strength of the prepared cellulose graphene composite short fiber can reach 3.4-3.8 cN/dtex when the filament number is 1.5dtex, the cellulose graphene composite short fiber has excellent mechanical properties and is also beneficial to large-scale spinning, the number of spinning holes is increased to 14000-30000 holes from 60-100 holes in the traditional laboratory stage during spinning, and industrial production is realized;

4) when the co-dissolution of the cellulose and the graphene oxide is realized, the dissolution temperature is obviously reduced, the dissolution time is obviously shortened, the cost is saved, the production efficiency is improved, and the industrial production is easy to realize;

5) the preparation process disclosed by the invention does not need a defoaming step, and the graphene oxide and the cellulose are dissolved in the ionic liquid together, so that the preparation process is economical and practical, simple, low in cost, free of any organic solvent, environment-friendly and pollution-free, free of special equipment and harsh conditions, easy to realize industrial production and high in practical value.

Detailed Description

The technical scheme of the invention is further detailed and completely explained by combining the embodiment, the application example and the comparative example.

Example 1

Preparation of mono-bis 1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt:

under the protection of nitrogen and at the temperature of 80 ℃, 1.2mol of N-methylimidazole is slowly dripped into 1mol of 1, 4-dichlorobutane, after the dripping is finished, the reflux reaction is carried out for 72 hours, the reaction is finished, the reaction liquid is cooled to the room temperature, the obtained product is washed by diethyl ether to remove the unreacted raw materials, and a white solid substance, namely the bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt (the HPLC purity is 98.8%, and the yield is 88%) is obtained.

Preparation of di, di 1, 4-bis [1- (3-methylimidazole) ] butyl diperchichloride:

dissolving 1mol of bis-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride and 1.2mol of lithium perchlorate in 1L of water, stirring and reacting at 80 ℃ for 36 hours, cooling to room temperature, continuing stirring at room temperature for 12 hours, dispersing the reaction solution into chloroform with the same volume, separating, washing a chloroform phase with water until the water phase has no chloride ions, and concentrating the chloroform phase under reduced pressure to obtain a colorless transparent liquid, namely bis-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride (the HPLC purity is 98.9%, and the yield is 78%).

Thirdly, preparing the ionic liquid:

uniformly mixing 100g of 1-butyl-3-methylimidazole chlorine salt, 8g of bis-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt and 15g of bis-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt, stirring and reacting at 125 ℃ for 11 hours, finishing the reaction, and cooling to room temperature to obtain the ionic liquid.

Fourthly, preparing the cellulose graphene composite short fiber:

a) dissolving the ionic liquid in deionized water to prepare 85 wt% of ionic liquid aqueous solution; uniformly mixing 0.5 part by mass of silicon oxide (the particle size is about 100nm), 0.01 part by mass of graphene oxide and 9.49 parts by mass of cotton pulp (the cellulose content is 99 percent, and the polymerization degree is 600), adding the mixture into 100 parts by mass and 85 wt% of ionic liquid aqueous solution, and stirring the mixture for 20 minutes at 75 ℃ to obtain stable and uniform mixed spinning stock solution;

b) filtering the obtained mixed spinning solution (the spinning solution can be spun only by filtering and defoaming in the traditional preparation method, and the process steps are complex), spinning by using a porous spinneret plate (the number of holes of the spinneret plate is 20000, the temperature of the spinning solution is 75 ℃, and the spinning speed is 100 m/min), immersing the spinning solution into a coagulating bath containing 15 wt% of ionic liquid for coagulation, wherein the temperature of the coagulating bath is 15 ℃, stretching by 3.5 times, washing, bleaching, oiling, cutting (50nm), and drying to obtain the cellulose graphene composite short fiber.

Through tests, the breaking strength of the cellulose graphene composite short fiber prepared in the embodiment is about 3.4cN/dtex under the condition that the filament number is 1.5 dtex; and the experiment shows that: under the same conditions, when 85 wt% of single ionic liquid aqueous solution of 1-butyl-3-methylimidazole chlorine salt, bis-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt or 1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt is adopted to dissolve graphene oxide and cotton pulp, stable and uniform spinning solution can be obtained only by stirring for 3-5 hours at 110-130 ℃, and the breaking strength of the prepared comparative cellulose graphene composite short fiber is only about 2.7cN/dtex under the condition that the filament number is the same as 1.5dtex, which indicates that the co-dissolution of cellulose and graphene oxide is realized and the mechanical property of the prepared cellulose graphene composite short fiber is better;

in addition, the specific resistance of the cellulose graphene composite short fiber prepared in the embodiment is 7.3 × 10⁵Omega.m or so, and the specific resistance of the composite short fiber is basically unchanged after washing and printing, and the specific resistance of the composite short fiber is 1.1 x 10⁶Omega · m or so, it can be seen that the cellulose graphene composite short fiber prepared by the preparation process of the embodiment has excellent antistatic performance and stability, and also has excellent antibacterial performance and far infrared performance.

In addition, in the embodiment, by using the ionic liquid, the ionic liquid aqueous solution is used for dissolving graphene and cellulose, but graphene and cellulose are not easily dissolved in water, and the added water is not beneficial to the dissolution of cellulose and graphene (which is also the reason why an organic solvent, such as DMSO, is added to a traditional ionic liquid to promote the dissolution of cellulose); in addition, the water is added into the dissolving system, so that the viscosity of the spinning solution can be reduced, and high-hole spinning is facilitated; in addition, the dissolving temperature is obviously reduced, and the dissolving time is obviously shortened.

The cellulose graphene composite staple fibers prepared by the embodiment have good mechanical properties and low viscosity of the spinning solution, so that the number of spinneret holes in the spinning process of the embodiment can reach 20000 holes, the spinning speed can be 100 m/min, and the industrial production is realized.

In the step a) of this embodiment, the mass part of the ionic liquid aqueous solution may be 30 to 95%, and the rest conditions are unchanged.

In the step a) of the present embodiment, the dissolution temperature may be 50 to 110 ℃, the dissolution time may be 10 to 45 minutes, and the rest conditions are unchanged.

The cotton pulp used in step a) of this example may be wood pulp, bamboo pulp, mulberry bark pulp, rice straw pulp, reed pulp, bagasse pulp or hemp pulp, with the remainder being unchanged.

In the embodiment, the adding amount of the silicon oxide in the step a) can be 0.3-1 wt% of the ionic liquid aqueous solution, and the rest conditions are unchanged.

In the step b) of the embodiment, the number of the spinning holes can be 14000-30000, the rest conditions are unchanged, the temperature of the spinning solution can be 50-110 ℃, the spinning speed can be 60-150 m/min, and the rest conditions are unchanged.

In the step b) of this embodiment, the coagulation bath may be 5-25 wt% of an ionic liquid aqueous solution, the temperature of the coagulation bath may be 0-20 ℃, and the rest conditions are unchanged.

In the step b) of this embodiment, the stretching may be 1.5 to 4 times of stretching, and the rest conditions are unchanged.

In the embodiment, the cutting length in the step b) can be 35-105 mm, and other conditions are unchanged.

Example 2

This embodiment differs from embodiment 1 only in that: 0.5 part by mass of silicon oxide (particle size of about 100nm), 0.015 part by mass of graphene oxide and 9.485 parts by mass of cotton pulp (cellulose content of 99%, degree of polymerization of 600) were mixed uniformly and added to 100 parts by mass of 85 wt% ionic liquid aqueous solution, and the rest was the same as described in example 1.

Through tests, the breaking strength of the cellulose graphene composite short fiber prepared in the embodiment is about 3.6cN/dtex under the condition that the filament number is 1.5 dtex; and the experiment shows that: under the same conditions, when 85 wt% of single ionic liquid aqueous solution of 1-butyl-3-methylimidazole chlorine salt, bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt or 1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt is adopted to dissolve graphene oxide and cotton pulp, stable and uniform spinning solution can be obtained only by stirring for 3-5 hours at 110-130 ℃, and the breaking strength of the prepared comparative cellulose graphene composite short fiber is only about 2.9cN/dtex under the condition that the filament number is 1.5 dtex;

in addition, the specific resistance of the cellulose graphene composite short fiber prepared in the embodiment is 4.1 × 10⁵Omega.m or so, and the specific resistance of the composite short fiber is basically unchanged after washing and printing, and the specific resistance of the composite short fiber is 7.5 x 10⁵Omega · m or so.

Example 3

This embodiment differs from embodiment 1 only in that: 0.5 part by mass of silicon oxide (particle size of about 100nm), 0.025 part by mass of graphene and 9.475 parts by mass of cotton pulp (cellulose content of 99%, degree of polymerization of 600) were mixed uniformly and added to 100 parts by mass of an 85 wt% ionic liquid aqueous solution, and the rest was the same as described in example 1.

Through tests, the breaking strength of the cellulose graphene composite short fiber prepared in the embodiment is about 3.8cN/dtex under the condition that the filament number is 1.5 dtex; and the experiment shows that: under the same conditions, when 85 wt% of single ionic liquid aqueous solution of 1-butyl-3-methylimidazole chlorine salt, bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt or 1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt is adopted to dissolve cotton pulp, graphene and cotton pulp, stable and uniform spinning solution can be obtained only by stirring for 3-5 hours at 110-130 ℃, and the breaking strength of the prepared comparative cellulose graphene composite short fiber is only about 3.0cN/dtex under the condition that the filament number is 1.5 dtex;

in addition, the specific resistance of the cellulose graphene composite short fiber prepared in the embodiment is 1.1 x 10⁵Omega.m or so, and the specific resistance after washing and printing and dyeing is basically not changed, and the specific resistance of the contrast cellulose graphene composite short fiber is 3.5 x 10⁵Omega · m or so.

As can be seen from examples 1 to 3, when the preparation process of the present invention is adopted, particularly when the composite ionic liquid of the present invention is adopted to dissolve cellulose and graphene oxide, and the breaking strength of the cellulose graphene composite short fiber prepared by the composite ionic liquid of the present invention is improved by more than 20% compared with that of the comparative cellulose graphene composite short fiber under the same single-filament fineness, the mechanical properties of the cellulose graphene composite short fiber prepared by the preparation process of the present invention are better, and particularly, the specific resistance of the cellulose graphene composite short fiber prepared by the present invention can reach 1.1 × 10⁵Omega.m, the specific resistance of the alloy is basically unchanged after washing and printing, the alloy can be repeatedly utilized for many times, the antistatic property is good,the stability is good.

In summary, the following steps: the invention prepares a novel ionic liquid by compounding 1-butyl-3-methylimidazole chlorine salt, bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt and bi-1, 4-bis [1- (3-methylimidazole) ] butyl dichloride salt, the obtained ionic liquid is used for preparing the cellulose graphene composite short fiber, the prepared cellulose graphene composite short fiber has excellent mechanical property and stability, in the preparation process, the dissolution of cellulose and graphene oxide can be realized without using pure ionic liquid, the dissolution temperature is effectively reduced, the dissolution time is shortened, the dissolution efficiency is improved, the agglomeration of graphene is avoided at the same time, and the use of the ionic liquid aqueous solution is lower than that of the pure ionic liquid in the viscosity of the obtained spinning solution, the concentration of the ionic liquid aqueous solution can be adjusted as required, and the viscosity of the spinning solution can be flexibly adjusted, so that the spinning solution is easy to spin, the number of spinneret holes can reach 14000-30000 holes during spinning, the spinning speed can be 60-150 m/min, and industrial production is realized; in addition, the preparation process disclosed by the invention does not need a defoaming step, and the graphene oxide and the cellulose can be dissolved in the ionic liquid together, so that the preparation process is economical and practical, simple, low in cost, free of any organic solvent, environment-friendly and pollution-free, free of special equipment and harsh conditions, easy to realize industrial production, and extremely high in practical value, and compared with the prior art, the preparation process disclosed by the invention is remarkably improved and has an unexpected effect.

Finally, it should be pointed out here that: the above is only a part of the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention, and the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above description are intended to be covered by the present invention.

Claims

1. The preparation method of the cellulose graphene composite short fiber is characterized by comprising the following steps:

a) mixing a dispersing agent, graphene oxide and cellulose, and dissolving the mixture in an ionic liquid aqueous solution with the mass fraction of 85-95%, wherein the addition amount of the graphene oxide is 0.1-0.3 wt% of the cellulose, so as to prepare a mixed spinning solution;

wherein the ionic liquid is prepared from the following components:

100 parts by mass of 1-butyl-3-methylimidazole chloride salt;

5-10 parts by mass of bis (1, 4-bis [1- (3-methylimidazole) ] butyl dichloride;

10-20 parts by mass of bis (1, 4-bis [1- (3-methylimidazole) ] butyl diperchichloride);

mixing to obtain; wherein:

2. the method of claim 1, wherein: the dissolving temperature in the step a) is 50-110 ℃, and the dissolving time is 10-45 minutes.

3. The method of claim 1, wherein the ionic liquid is prepared by the steps of:

4. The method according to claim 3, wherein the bis-1, 4-bis [1- (3-methylimidazole) ] butyldichloride salt is prepared by the steps of: dropwise adding N-methylimidazole into 1, 4-dichlorobutane at the temperature of 65-85 ℃ under the protection of inert gas, and then carrying out reflux reaction for 12-72 hours.

5. The method according to claim 3, wherein the bis-1, 4-bis [1- (3-methylimidazole) ] butyl diperchichlorate is prepared by the steps of:

6. The method of claim 1, wherein: the cellulose is selected from any one of wood pulp, cotton pulp, bamboo pulp, mulberry bark pulp, rice straw pulp, reed pulp, cane bagasse pulp or hemp pulp, the cellulose content is more than or equal to 90 wt%, and the polymerization degree is more than or equal to 500.

7. The method of claim 1, wherein: the dispersing agent is silicon oxide, and the addition amount of the dispersing agent is 0.3-1 wt% of the ionic liquid aqueous solution.

8. The method of claim 1, wherein: in the step b), the cutting length is 35-105 mm.