阅读说明：本技术 一种介孔纤维素纤维材料的制备方法 (Preparation method of mesoporous cellulose fiber material ) 是由 程有亮 赵维娜 方长青 陈静 王莎 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种介孔纤维素纤维材料的制备方法,对微晶纤维素进行酸解、离心、透析、超声、蒸发制备纤维素纳米晶材料；将正硅酸乙酯与盐酸在水浴条件下预水解,得到SiO-(2)前驱体溶液；将SiO-(2)前驱体溶液加入纤维素纳米晶材料中,在60℃下搅拌3h,再在室温下蒸发诱导自组装,得到混合溶液；将混合溶液通过挤出泵挤入凝固浴中浸泡,水洗、晾干得到复合纤维材料；对复合纤维材料采用氢氟酸溶液去除SiO-(2)后,用乙醇洗涤,再通过真空冷冻干燥,得到介孔纤维素纤维材料；工艺简单、环境友好、原材料来源广泛、易于得到定向纤维；所获介孔纤维素纤维材料具有优异的介孔结构和高的比表面积,将其作为功能载体材料,具有广泛的应用前景。(The invention discloses a preparation method of a mesoporous cellulose fiber material, which is characterized in that a cellulose nanocrystalline material is prepared by carrying out acidolysis, centrifugation, dialysis, ultrasound and evaporation on microcrystalline cellulose; prehydrolysis of ethyl orthosilicate and hydrochloric acid in water bath to obtain SiO 2 Precursor solution; mixing SiO 2 Adding the precursor solution into a cellulose nanocrystalline material, stirring for 3 hours at 60 ℃, and evaporating at room temperature to induce self-assembly to obtain a mixed solution; extruding the mixed solution into a coagulating bath through an extrusion pump, soaking, washing with water, and airing to obtain a composite fiber material; the composite fiber material is dissolved by hydrofluoric acidLiquid SiO removal 2 Then washing with ethanol, and then carrying out vacuum freeze drying to obtain a mesoporous cellulose fiber material; the process is simple, environment-friendly, wide in raw material source and easy to obtain oriented fibers; the obtained mesoporous cellulose fiber material has an excellent mesoporous structure and a high specific surface area, and has a wide application prospect when being used as a functional carrier material.)

1. A preparation method of a mesoporous cellulose fiber material is characterized by comprising the following steps:

step 1, carrying out acidolysis, centrifugation, dialysis, ultrasound and evaporation on microcrystalline cellulose to prepare a cellulose nanocrystalline material;

step 2, prehydrolyzing ethyl orthosilicate and hydrochloric acid under the water bath condition to obtain SiO₂Precursor solution;

step 3, mixing SiO₂Adding the precursor solution into a cellulose nanocrystalline material, stirring for 3 hours at 60 ℃, and evaporating at room temperature to induce self-assembly to obtain a mixed solution;

step 4, extruding the mixed solution into a coagulating bath through an extrusion pump for soaking, washing with water, and airing to obtain a composite fiber material;

step 5, removing SiO from the composite fiber material by adopting hydrofluoric acid solution₂And then washing with ethanol, and performing vacuum freeze drying to obtain the mesoporous cellulose fiber material.

2. The preparation method of the mesoporous cellulose fiber material according to claim 1, wherein the step 1 comprises the following steps:

step 1.1, preparing concentrated sulfuric acid with the mass fraction of 64%, stirring in a constant-temperature water bath at 45-60 ℃, adding microcrystalline cellulose after the solution temperature is stable, wherein each gram of microcrystalline cellulose corresponds to 8.75ml of sulfuric acid, reacting for 30-45min at the stirring speed of 300-600rpm, and pouring into 10 times of volume of deionized water after the reaction is finished to obtain a mixed solution A;

step 1.2, standing the mixed solution A for 12-24h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution for 20-30min at 9000-;

and step 1.3, putting the milky white suspension into a dialysis bag for dialysis, wherein the dialysis time is 3-6 days, replacing deionized water every 6 hours, collecting the liquid in the dialysis bag, carrying out ultrasonic crushing on the liquid in the dialysis bag for 10-20min at the power of 180W, pouring the liquid into an evaporation dish, and evaporating to obtain the cellulose nanocrystalline material with the mass fraction of 3% -5%.

3. The preparation method of the mesoporous cellulose fiber material according to claim 1, wherein the step 2 comprises the following steps:

adding tetraethoxysilane into hydrochloric acid with the concentration of 0-0.1mol/L, wherein the mass ratio of tetraethoxysilane to hydrochloric acid is 2:1, the water bath temperature is 0-60 ℃, and the prehydrolysis time is 0-5h, so as to obtain SiO₂And (3) precursor solution.

4. The method for preparing mesoporous cellulose fiber material according to claim 1, wherein the SiO in step 3 is₂When the precursor solution is added into the cellulose nanocrystalline material, each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂And (3) precursor solution.

5. The method for preparing mesoporous cellulose fiber material according to claim 1, wherein the time for evaporation-induced self-assembly at room temperature in step 3 is 6-48 h.

6. The method for preparing mesoporous cellulose fiber material according to claim 1, wherein the coagulating bath in step 4 is 15% sodium hydroxide, 95% ethanol and 8% aluminum potassium sulfate in a volume ratio of 2:3: 2.

7. The method for preparing mesoporous cellulose fiber material according to claim 1, wherein the time for soaking the mixed solution in the coagulating bath in step 4 is 30-60 min.

8. The method for preparing mesoporous cellulose fiber material according to claim 1, wherein the SiO in the composite fiber material is removed by hydrofluoric acid solution in step 5₂The specific process is as follows: completely soaking the composite fiber material in 5 percent hydrofluoric acid solution for 30-60 min.

Technical Field

The invention belongs to the technical field of composite material preparation, and particularly relates to a preparation method of a mesoporous cellulose fiber material.

Background

With the rapid development of modern industrial and scientific technology in the 21 st century, the demand for high-performance materials, especially high-performance fiber materials, is increasing. The fiber material not only has the performance characteristics of surface-interface characteristics, processability, composite combinability, functionality and the like, but also has the advantages of wide raw material source, low production cost, easy regulation and control of production process and the like, so that the research and development and the manufacture of high-performance fiber materials become hot spots. The development of high-performance fiber materials is the key for improving the traditional industry, the surface of the traditional fiber materials is smooth and difficult to meet the actual requirement, and the specific surface area, the surface energy and the surface activity are main factors for restricting the performance of the traditional fiber materials. The porous material has the characteristics of high specific surface area, low relative density, high porosity and the like, wherein the mesoporous material is unique in the field of porous materials by the advantages of large specific surface area, adjustable pore diameter and the like, and the application fields of the mesoporous material include adsorption separation, energy storage, electrochemistry, sensors, anti-counterfeiting and the like.

The porous fiber material mainly refers to a fiber material with a large number of pores on the surface or inside, meanwhile, the pores can be used for meeting certain design requirements or certain design requirements so as to achieve important materials with expected service performance indexes, and the introduction of a porous structure greatly improves the specific surface area of the fiber, so that the fiber performance is improved. At present, methods for preparing porous fiber materials include template synthesis methods, wet spinning, phase separation methods, electrospinning, and the like.

The environment and resources are hot problems of contemporary society, and it is necessary to satisfy the demands of people on fibers on the premise of resource shortage and environmental friendliness. At present, an electrostatic spinning method is usually adopted for preparing the porous fiber material, but the method is mostly required to be carried out in a strong corrosive or highly toxic solvent, such as dimethylformamide, tetrahydrofuran, dichloromethane and the like, the organic solvent has high cost, is not easy to recover, and is easy to cause environmental pollution, and in addition, the electrostatic spinning is difficult to obtain the nano fibers separated from each other.

Disclosure of Invention

The invention aims to provide a preparation method of a mesoporous cellulose fiber material, which can effectively avoid using a strong corrosive or highly toxic organic solvent.

The technical scheme adopted by the invention is that the preparation method of the mesoporous cellulose fiber material is implemented according to the following steps:

step 1, carrying out acidolysis, centrifugation, dialysis, ultrasound and evaporation on microcrystalline cellulose to prepare a cellulose nanocrystalline material;

step 2, prehydrolyzing ethyl orthosilicate and hydrochloric acid under the water bath condition to obtain SiO₂Precursor solution;

step 3, mixing SiO₂Adding the precursor solution into a cellulose nanocrystalline material, stirring for 3 hours at 60 ℃, and evaporating at room temperature to induce self-assembly to obtain a mixed solution;

step 4, extruding the mixed solution into a coagulating bath through an extrusion pump for soaking, washing with water, and airing to obtain a composite fiber material;

step 5, removing SiO from the composite fiber material by adopting hydrofluoric acid solution₂And then washing with ethanol, and performing vacuum freeze drying to obtain the mesoporous cellulose fiber material.

The invention is also characterized in that:

the specific process of the step 1 is as follows:

step 1.1, preparing concentrated sulfuric acid with the mass fraction of 64%, stirring in a constant-temperature water bath at 45-60 ℃, adding microcrystalline cellulose after the solution temperature is stable, wherein each gram of microcrystalline cellulose corresponds to 8.75ml of sulfuric acid, reacting for 30-45min at the stirring speed of 300-600rpm, and pouring into 10 times of volume of deionized water after the reaction is finished to obtain a mixed solution A;

step 1.2, standing the mixed solution A for 12-24h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution for 20-30min at 9000-;

and step 1.3, putting the milky white suspension into a dialysis bag for dialysis, wherein the dialysis time is 3-6 days, replacing deionized water every 6 hours, collecting the liquid in the dialysis bag, carrying out ultrasonic crushing on the liquid in the dialysis bag for 10-20min at the power of 180W, pouring the liquid into an evaporation dish, and evaporating to obtain the cellulose nanocrystalline material with the mass fraction of 3% -5%.

The specific process of the step 2 is as follows:

adding tetraethoxysilane into hydrochloric acid with the concentration of 0-0.1mol/L, wherein the mass ratio of tetraethoxysilane to hydrochloric acid is 2:1, the water bath temperature is 0-60 ℃, and the prehydrolysis time is 0-5h, so as to obtain SiO₂And (3) precursor solution.

SiO in step 3₂When the precursor solution is added into the cellulose nanocrystalline material, each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂And (3) precursor solution.

And in the step 3, the time for evaporation to induce self-assembly at room temperature is 6-48 h.

In the step 4, the coagulating bath comprises 15% of sodium hydroxide, 95% of ethanol and 8% of aluminum potassium sulfate in a volume ratio of 2:3: 2.

And 4, extruding the mixed solution into a coagulating bath through an extrusion pump for soaking for 30-60 min.

In step 5, the composite fiber material is subjected to hydrofluoric acid solution to remove SiO₂The specific process is as follows: completely soaking the composite fiber material in 5 percent hydrofluoric acid solution for 30-60 min.

The invention has the beneficial effects that:

according to the preparation method of the mesoporous cellulose fiber material, the green, environment-friendly and renewable cellulose nanocrystals are used as the raw material, so that the problem of resource shortage in the future is solved; moreover, the preparation method is based on wet spinning, adopts the technology of extrusion by an extrusion pump, effectively avoids using a strong corrosive or highly toxic organic solvent, does not pollute the environment, has simple process, can collect the oriented fiber, and has wide application prospect in the field of functional carrier materials.

Drawings

FIG. 1 is a scanning electron microscope image of a mesoporous cellulose fiber material prepared in example 1;

FIG. 2 is a scanning electron microscope image of a mesoporous cellulose fiber material prepared in example 2;

FIG. 3 is a scanning electron microscope image of the mesoporous cellulose fiber material prepared in example 3.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention relates to a preparation method of a mesoporous cellulose fiber material, which is implemented according to the following steps:

preparing concentrated sulfuric acid with the mass fraction of 64%, stirring in a constant-temperature water bath at 45-60 ℃, adding microcrystalline cellulose after the solution temperature is stable, wherein each gram of microcrystalline cellulose corresponds to 8.75ml of sulfuric acid, reacting for 30-45min at the stirring speed of 300-600rpm, and pouring into 10 times of volume of deionized water after the reaction is finished to obtain a mixed solution A; standing the mixed solution A for 12-24h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution for 20-30min by a centrifuge at 9000-; and putting the milky white suspension into a dialysis bag for dialysis, wherein the dialysis time is 3-6 days, replacing deionized water every 6 hours, collecting the liquid in the dialysis bag, carrying out ultrasonic crushing on the liquid in the dialysis bag for 10-20min at the power of 180W, pouring the liquid into an evaporation dish, and evaporating to obtain the cellulose nanocrystalline material with the mass fraction of 3% -5%. Adding tetraethoxysilane into hydrochloric acid with the concentration of 0-0.1mol/L, wherein the mass ratio of tetraethoxysilane to hydrochloric acid is 2:1, the water bath temperature is 0-60 ℃, and the prehydrolysis time is 0-5h, so as to obtain SiO₂Precursor solution; mixing SiO₂Adding the precursor solution into the cellulose nanocrystalline material, wherein each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂Stirring the precursor solution at 60 ℃ for 3h, and then evaporating at room temperature to induce self-assembly for 6-48h to obtain a mixed solution; extruding the mixed solution into a coagulating bath by an extrusion pump, soaking for 30-60min, wherein the coagulating bath is 15% sodium hydroxide, 95% ethanol and 8% aluminum potassium sulfate in a volume ratio of 2:3:2, and completely drying the composite fiber material by vacuum freeze dryingSoaking in 5 percent hydrofluoric acid solution to remove SiO₂Soaking for 30-60min, washing with water, and air drying to obtain composite fiber material and mesoporous cellulose fiber material.

Example 1

The invention relates to a preparation method of a mesoporous cellulose fiber material, which is implemented according to the following steps:

preparing concentrated sulfuric acid with the mass fraction of 64%, stirring the concentrated sulfuric acid in a constant-temperature water bath at 45 ℃, adding microcrystalline cellulose after the temperature of the solution is stable, wherein each gram of microcrystalline cellulose corresponds to 8.75ml of sulfuric acid, reacting the mixture for 30min at the stirring speed of 300rpm, and pouring the mixture into deionized water with the volume of 10 times of the volume of the mixture after the reaction is finished to obtain a mixed solution A; standing the mixed solution A for 12h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution by a centrifuge at 9000rmp for 20min to obtain a milky suspension; and (3) putting the milky white suspension into a dialysis bag (8KD) for dialysis, wherein the dialysis time is 3 days, replacing deionized water every 6 hours, collecting the liquid in the dialysis bag, carrying out ultrasonic crushing on the liquid in the dialysis bag for 10min at the power of 180W, pouring the liquid into an evaporation dish, and evaporating to obtain the cellulose nanocrystalline material with the mass fraction of 3%. Adding 600 mu L of tetraethoxysilane into deionized water, wherein the mass ratio of tetraethoxysilane to deionized water is 2:1, the water bath temperature is 60 ℃, and the prehydrolysis time is 1.2h, so as to obtain SiO₂Precursor solution; mixing SiO₂Adding the precursor solution into the cellulose nanocrystalline material, wherein each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂Stirring the precursor solution at 60 ℃ for 3h, and then evaporating at room temperature to induce self-assembly for 6h to obtain a mixed solution; extruding the mixed solution into a coagulating bath through an extrusion pump, soaking for 30min, wherein the coagulating bath comprises 15% of sodium hydroxide, 95% of ethanol and 8% of aluminum potassium sulfate according to the volume ratio of 2:3:2, and completely soaking the composite fiber material into a hydrofluoric acid solution with the mass fraction of 5% to remove SiO through vacuum freeze drying₂And soaking for 30min, washing with water, and air drying to obtain composite fiber material and mesoporous cellulose fiber material, wherein the scanning electron microscope image is shown in FIG. 1.

Example 2

The invention relates to a preparation method of a mesoporous cellulose fiber material, which is implemented according to the following steps:

preparing concentrated sulfuric acid with the mass fraction of 64%, stirring the concentrated sulfuric acid in a constant-temperature water bath at 45 ℃, adding microcrystalline cellulose after the temperature of the solution is stable, wherein each gram of microcrystalline cellulose corresponds to 8.75ml of sulfuric acid, reacting the mixture for 35min at the stirring speed of 350rpm, and pouring the mixture into deionized water with the volume of 10 times of the volume of the mixture after the reaction is finished to obtain a mixed solution A; standing the mixed solution A for 15h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution by a centrifuge at 9000rmp for 23min to obtain a milky suspension; and (3) putting the milky white suspension into a dialysis bag (9KD) for dialysis, wherein the dialysis time is 3 days, replacing deionized water every 6 hours, collecting the liquid in the dialysis bag, carrying out ultrasonic crushing on the liquid in the dialysis bag for 12min at the power of 180W, pouring the liquid into an evaporation dish, and evaporating to obtain the cellulose nanocrystalline material with the mass fraction of 3%. Adding 900 mu L of tetraethoxysilane into hydrochloric acid with the concentration of 0.1mol/L, wherein the mass ratio of tetraethoxysilane to hydrochloric acid is 2:1, the water bath temperature is 10 ℃, and the prehydrolysis time is 5h, so as to obtain SiO₂Precursor solution; mixing SiO₂Adding the precursor solution into the cellulose nanocrystalline material, wherein each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂Stirring the precursor solution at 60 ℃ for 3h, and then evaporating at room temperature to induce self-assembly for 12h to obtain a mixed solution; extruding the mixed solution into a coagulating bath through an extrusion pump, soaking for 36min, wherein the coagulating bath comprises 15% of sodium hydroxide, 95% of ethanol and 8% of aluminum potassium sulfate according to the volume ratio of 2:3:2, and completely soaking the composite fiber material into a hydrofluoric acid solution with the mass fraction of 5% to remove SiO through vacuum freeze drying₂And soaking for 35min, washing with water, and air drying to obtain composite fiber material and mesoporous cellulose fiber material, wherein the scanning electron microscope image is shown in FIG. 2.

Example 3

The invention relates to a preparation method of a mesoporous cellulose fiber material, which is implemented according to the following steps:

preparing 64% concentrated sulfuric acid, stirring in a constant-temperature water bath at 48 ℃, adding microcrystalline cellulose after the solution temperature is stable, wherein each gram of microcrystalline cellulose corresponds to 875ml of sulfuric acid reacts for 35min at the stirring speed of 350rpm, and is poured into deionized water with the volume of 10 times of that of the sulfuric acid after the reaction is finished to obtain mixed liquid A; standing the mixed solution A for 15h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution by a centrifuge at 10000rmp for 25min to obtain a milky suspension; and (3) putting the milky white suspension into a dialysis bag (10KD) for dialysis, wherein the dialysis time is 5 days, replacing deionized water every 6 hours, collecting the liquid in the dialysis bag, carrying out ultrasonic crushing on the liquid in the dialysis bag for 15min at the power of 180W, pouring the liquid into an evaporation dish, and evaporating to obtain the cellulose nanocrystalline material with the mass fraction of 4%. Adding 1200 mu L of tetraethoxysilane into hydrochloric acid with the concentration of 0.1mol/L, wherein the mass ratio of tetraethoxysilane to hydrochloric acid is 2:1, the water bath temperature is 50 ℃, and the prehydrolysis time is 4h to obtain SiO₂Precursor solution; mixing SiO₂Adding the precursor solution into the cellulose nanocrystalline material, wherein each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂Stirring the precursor solution at 60 ℃ for 3h, and then evaporating at room temperature to induce self-assembly for 12h to obtain a mixed solution; extruding the mixed solution into a coagulating bath through an extrusion pump, soaking for 45min, wherein the coagulating bath comprises 15% of sodium hydroxide, 95% of ethanol and 8% of aluminum potassium sulfate in a volume ratio of 2:3:2, and completely soaking the composite fiber material into a hydrofluoric acid solution with the mass fraction of 5% to remove SiO through vacuum freeze drying₂Soaking for 45min, washing with water, and air drying to obtain composite fiber material, and scanning electron microscope image is shown in FIG. 3.

Example 4

The invention relates to a preparation method of a mesoporous cellulose fiber material, which is implemented according to the following steps:

preparing concentrated sulfuric acid with the mass fraction of 64%, stirring the concentrated sulfuric acid in a constant-temperature water bath at 55 ℃, adding microcrystalline cellulose after the temperature of the solution is stable, wherein each gram of microcrystalline cellulose corresponds to 8.75ml of sulfuric acid, reacting the mixture for 40min at the stirring speed of 550rpm, and pouring the mixture into deionized water with the volume of 10 times of the volume of the mixture after the reaction is finished to obtain a mixed solution A; standing the mixed solution A for 18h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution at 11000rmp centrifuging for 25min to obtain milky white suspension; and (3) putting the milky white suspension into a dialysis bag (12KD) for dialysis, wherein the dialysis time is 5 days, replacing deionized water every 6 hours, collecting the liquid in the dialysis bag, carrying out ultrasonic crushing on the liquid in the dialysis bag for 18min at the power of 180W, pouring the liquid into an evaporation dish, and evaporating to obtain the cellulose nanocrystalline material with the mass fraction of 5%. Adding 1500 mu L of tetraethoxysilane into hydrochloric acid with the concentration of 0.1mol/L, wherein the mass ratio of tetraethoxysilane to hydrochloric acid is 2:1, the water bath temperature is 50 ℃, and the prehydrolysis time is 4h to obtain SiO₂Precursor solution; mixing SiO₂Adding the precursor solution into the cellulose nanocrystalline material, wherein each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂Stirring the precursor solution at 60 ℃ for 3h, and then evaporating at room temperature to induce self-assembly for 24h to obtain a mixed solution; extruding the mixed solution into a coagulating bath by an extrusion pump, soaking for 50min, wherein the coagulating bath comprises 15% of sodium hydroxide, 95% of ethanol and 8% of aluminum potassium sulfate in a volume ratio of 2:3:2, and completely soaking the composite fiber material in a hydrofluoric acid solution with the mass fraction of 5% to remove SiO through vacuum freeze drying₂And soaking for 50min, washing with water, and air drying to obtain the composite fiber material and the mesoporous cellulose fiber material.

Example 5

The invention relates to a preparation method of a mesoporous cellulose fiber material, which is implemented according to the following steps:

preparing concentrated sulfuric acid with the mass fraction of 64%, stirring the concentrated sulfuric acid in a constant-temperature water bath at 60 ℃, adding microcrystalline cellulose after the temperature of the solution is stable, wherein each gram of microcrystalline cellulose corresponds to 8.75ml of sulfuric acid, reacting the mixture for 45min at the stirring speed of 600rpm, and pouring the mixture into deionized water with the volume of 10 times of the volume of the mixture after the reaction is finished to obtain a mixed solution A; standing the mixed solution A for 24h, pouring out the supernatant to obtain a lower milky turbid solution, and centrifuging the lower milky turbid solution by a centrifuge at 12000rmp for 30min to obtain a milky suspension; dialyzing the milky white suspension in dialysis bag (14KD) for 6 days, replacing deionized water every 6 hr, collecting the solution in dialysis bag, ultrasonically crushing the solution in dialysis bag at 180W for 20min, pouring into evaporation dish, and evaporating to obtain fiber with mass fraction of 5%A vitamin nanocrystalline material. Adding 1500 mu L of tetraethoxysilane into hydrochloric acid with the concentration of 0.1mol/L, wherein the mass ratio of tetraethoxysilane to hydrochloric acid is 2:1, the water bath temperature is 60 ℃, and the prehydrolysis time is 5h to obtain SiO₂Precursor solution; mixing SiO₂Adding the precursor solution into the cellulose nanocrystalline material, wherein each 1mg of the cellulose nanocrystalline material corresponds to 2 mu L of SiO₂Stirring the precursor solution at 60 ℃ for 3h, and then evaporating at room temperature to induce self-assembly for 48h to obtain a mixed solution; extruding the mixed solution into a coagulating bath through an extrusion pump, soaking for 60min, wherein the coagulating bath is 15% of sodium hydroxide, 95% of ethanol and 8% of aluminum potassium sulfate in a volume ratio of 2:3:2, washing for 3 times by using deionized water, and completely soaking the composite fiber material into a hydrofluoric acid solution with the mass fraction of 5% to remove SiO through vacuum freeze drying₂Soaking for 60min, washing with absolute ethanol for 2 times, and air drying to obtain the composite fiber material and the mesoporous cellulose fiber material.

Comparative example 1

Preparing concentrated sulfuric acid with the mass fraction of 64%, stirring the concentrated sulfuric acid in a constant-temperature water bath at 45 ℃, adding 23.2g of microcrystalline cellulose after the solution temperature is stable, reacting for 45min at the stirring speed of 600rpm, and pouring the solution into deionized water with the volume of 10 times of the solution to stop the reaction after the reaction is finished. Standing the mixed solution overnight, pouring out the supernatant, centrifuging the lower milky turbid solution for multiple times by using a high-speed centrifuge (9000rmp for 20min) until the upper turbid solution is turbid, and collecting the obtained suspension. The milky white suspension was dialyzed in dialysis bag (MWCO: 8-14KD) for 4 days, the deionized water was changed every 8 hours, and the solution in the dialysis bag was collected. The collected internal solution was further sonicated at 60% power for 10min, and then poured into an evaporating dish and evaporated at room temperature to obtain 3 wt% CNCs. Extruding the CNCs into a coagulating bath of 15% NaOH, 95% ethanol and 8% aluminum potassium sulfate (volume ratio of 2:3:2) by an extrusion pump, soaking for 40min, taking out the fiber, washing with deionized water for 3 times, and performing vacuum freeze drying to obtain the cellulose fiber material.

Comparative example 2

TEOS was prehydrolyzed with 0.1mol/L hydrochloric acid in a water bath at 60 ℃ for 1 h. The obtained SiO₂The precursor solution passes through an extrusion pumpSqueezing into coagulating bath containing 15% NaOH, 95% ethanol and 8% aluminum potassium sulfate (volume ratio of 2:3:2), soaking for 40min, taking out reaction product, washing with deionized water for 3 times, and vacuum freeze drying to obtain SiO₂And (4) obtaining a final product.

The invention selects the cellulose nanocrystal as the raw material because of good mechanical property, good biocompatibility, large specific surface area and unique self-assembly characteristic of the cellulose nanocrystal. Tetraethoxysilane is used as a silicon source, and silicon dioxide is formed through hydrolysis. Based on wet spinning, an extrusion pump is adopted for extrusion to form a fibrous composite material, and then nano silicon dioxide on the surface and inside of cellulose is removed through hydrofluoric acid to form a mesoporous structure, so that the mesoporous cellulose fiber material is obtained. The obtained fiber material has an excellent mesoporous structure and a high specific surface area, and has a wide application prospect when being used as a functional carrier material.

The present invention is described in detail below with reference to specific examples, and table 1 shows the mass fraction of the reaction raw materials, the component ratios, and the evaporation-induced self-assembly time parameters.

The mesoporous cellulose fiber materials obtained in examples 1 to 5 were subjected to surface area ratio and N₂The results of the adsorption isotherm analysis are shown in Table 2. As can be seen from table 2, the macroscopic length, specific surface area, mesoporous pore diameter and pore volume of the mesoporous cellulose fiber material are shown. It is thus found that the fiber materials obtained in examples 1 to 5 have relatively excellent mesoporous structures and high specific surface areas.

TABLE 2

The fiber material obtained by comparative example 1 was soft and difficult to remove from the coagulation bath, and fiber was broken and dissolved during washing of the fiber with deionized water to remove the surface coagulation bath components. The improvement of the addition of ethyl orthosilicate compared to examples 1-5 is illustratedThe properties of the fibres, i.e. SiO obtained by hydrolysis₂The precursor has a skeleton supporting effect on the cellulose, and contributes to the difficulty of breaking of the fiber material.

SiO in comparative example 2₂The precursor solution is not able to solidify in the coagulation bath of NaOH, ethanol and aluminum potassium sulfate, is miscible with the coagulation bath, and is SiO alone₂The precursor solution is processed through an extrusion and coagulation bath to obtain no fiber. Thus, a fibrous material is expected, and cellulose is also an indispensable raw material.

Through the mode, the preparation method of the mesoporous cellulose fiber material has the advantages of simple process, environmental friendliness, wide raw material source and easiness in obtaining the oriented fiber; the obtained mesoporous cellulose fiber material has an excellent mesoporous structure and a high specific surface area, and has a wide application prospect when being used as a functional carrier material.