CN113667189B

CN113667189B - Cellulose membrane and preparation method and application thereof

Info

Publication number: CN113667189B
Application number: CN202010414260.9A
Authority: CN
Inventors: 田卫国; 程一休; 张晓程; 张军
Original assignee: Institute of Chemistry CAS
Current assignee: Institute of Chemistry CAS
Priority date: 2020-05-15
Filing date: 2020-05-15
Publication date: 2022-08-30
Anticipated expiration: 2040-05-15
Also published as: CN113667189A

Abstract

The invention discloses a cellulose membrane and a preparation method and application thereof. The cellulose film comprises: the light scattering medium is at least one of biomass and biomass derivatives. The solubility difference of different substances in the same system is utilized, so that the substance with poor solubility serves as a light scattering medium in the cellulose membrane, and the surface roughness of the cellulose membrane is increased, thereby realizing the preparation of the cellulose membrane with high haze and high light transmittance; or the solubility difference of the same substance under different conditions is utilized, so that the incompletely dissolved substance serves as a light scattering medium in the cellulose membrane, and the surface roughness of the cellulose membrane is increased, thereby realizing the preparation of the high-haze high-light-transmittance film. The obtained cellulose film material with both high light transmittance and high haze has the light transmittance kept above 75% and the haze adjustable between 5-95%, and is an ideal bio-based degradable light diffusion material.

Description

Cellulose membrane and preparation method and application thereof

Technical Field

The invention belongs to the technical field of biomass photoelectric materials, and relates to a cellulose membrane, and a preparation method and application thereof.

Background

The haze is a ratio of a scattered light flux which is transmitted through a sample and deviates from an incident light direction to a transmitted light flux, and is generally calculated by using a scattered light flux which deviates from the incident light direction by 2.5 ° or more in percentage. The light transmittance is the ratio of the luminous flux transmitted through the sample to the incident luminous flux, expressed as a percentage. The common transparent materials have higher light transmittance and lower haze, and the high-haze high-light-transmittance material can not only allow light to pass, but also effectively scatter incident light, and can convert the traditional point light source into a surface light source. The haze requirements of different application fields on materials are different, such as liquid crystal displays, touch screens and the like, so that the desired material has higher light transmittance and lower haze; the material is expected to have higher light transmittance and higher haze in the fields of outdoor displays, solar cells and the like. The outdoor display has the effect of square glare only when the haze is greater than 40%, and the high-haze material can improve the optical coupling rate of the material by increasing the transmission path of light inside the material through scattering action, so that the light conversion efficiency of the solar cell is improved. The LED has the advantages of high brightness, less heat generation, long service life, and the like. However, the LED light source is highly directional, and in the use process, the backlight unit is an essential optoelectronic element, and the key material in the backlight unit is a high-haze high-transmittance material with a light scattering effect.

With the increasing severity of energy problems, renewable green pure natural materials are receiving attention from people. Cellulose is a natural high polymer material with the largest reserve in nature, has the advantages of wide source, degradability, regeneration, low pollution and the like, and the development and utilization of the renewable resource also draw the wide attention of the society. At present, a great number of researchers use the pure natural biomass material to prepare a high-haze high-transmittance material, and the material has excellent performance. But a method for preparing the haze-adjustable cellulose-based film can be developed, and the preparation method is simple and feasible, and still has great practical significance for large-scale production.

Disclosure of Invention

The present invention provides a cellulose membrane based on the selective solubilization of different biomasses or biomass derivatives in ionic liquids, comprising: a cellulose membrane matrix and a light scattering medium uniformly dispersed in the form of particles in the cellulose membrane matrix, the light scattering medium may be at least one of a biomass and a biomass derivative; for example, the light scattering medium may be selected from at least one of chitosan, chitin, starch, lignin, cellulose esters, cellulose ethers, and microcrystalline cellulose; wherein, the cellulose ester can be selected from at least one of cellulose acetate, cellulose acetate butyrate, cellulose propionate, cellulose butyrate, cellulose nitrate, cellulose sulfate, cellulose benzoate and cellulose cinnamate, the cellulose ether can be selected from at least one of methyl cellulose, ethyl cellulose, carboxymethyl cellulose and hydroxyethyl cellulose, and the lignin can be selected from at least one of alkali lignin, sulfate lignin, solvent lignin, acid hydrolysis lignin and enzyme method lignin. Illustratively, the light scattering medium is chitosan, microcrystalline cellulose, or lignin.

According to embodiments of the invention, the mass ratio of the cellulose membrane matrix and the light scattering medium may be 1 (0.02-0.75), for example a mass ratio of 1 (0.05-0.5), such as 1 (0.0625-0.35), illustratively a mass ratio of 1:0.125, 1:0.1875, 1:0.25, or 1: 0.5.

According to an embodiment of the present invention, the particle size of the light scattering medium is 100-.

According to the embodiment of the present invention, the material of the cellulose membrane substrate may be at least one of cotton pulp cellulose, microcrystalline cellulose, wood pulp, bamboo pulp, absorbent cotton, bagasse, wood, and cellulose prepared from plant stalks (e.g., wheat straw, rape straw, corn straw, rice straw, etc.), and is preferably cotton pulp cellulose.

According to an embodiment of the present invention, the cellulose film has a light transmittance of 75% or more, such as 78% or more, preferably 84% or more, more preferably 85% or more.

According to an embodiment of the invention, the cellulose film has a haze of between 5 and 95%, such as between 8 and 85%, as well as between 30 and 75%.

According to an embodiment of the invention, the cellulose film has a thickness of 20-80 μm, such as 30-60 μm, further such as 40-50 μm.

The invention also provides a preparation method of the cellulose membrane, which comprises the following steps:

(1) dispersing a light scattering medium into a uniform solution of a cellulose membrane matrix/ionic liquid, wherein the light scattering medium is in a suspension state in the uniform solution;

(2) and (2) after the solution system in the step (1) is formed into a film, placing the film in a coagulating bath for regeneration to obtain a cellulose gel film, and drying the cellulose gel film to obtain the cellulose film.

According to an embodiment of the present invention, the light scattering medium and the cellulose film matrix both have the meaning and mass ratio as described above.

According to an embodiment of the present invention, in the step (1), in the homogeneous solution of the cellulose membrane matrix/ionic liquid, the mass ratio of the cellulose membrane matrix to the ionic liquid may be (0.01-0.1):1, for example (0.02-0.07):1, illustratively 0.04:1, 0.05: 1.

According to an embodiment of the invention, in step (1), the ionic liquid is an organic molten salt formed by cations and anions of the imidazole or pyridine type, having a melting point lower than 100 ℃. For example, the ionic liquid is selected from ionic liquids which can dissolve a matrix material of the cellulose film but are insoluble or hardly soluble in the light scattering medium at the same temperature when heated, or can make the light scattering medium insoluble or hardly soluble in the light scattering medium by a temperature difference. For example, the cation of the ionic liquid is selected from at least one of the following: 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, N-ethylpyridinium cation, N-butylpyridinium cation, N-hexylpyridineium cation; illustratively, the cation is selected from at least one of the following: 1-ethyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium cation and 1-butyl-3-methylimidazolium cation.

For example, the anion of the ionic liquid is selected from at least one of: chloride, bromide, formate, acetate, propionate, butyrate, and methyl phosphate ions; illustratively, the anion is selected from at least one of: chloride, formate, acetate and methyl phosphate ions.

According to an exemplary aspect of the invention, the ionic liquid may be selected from an AmimCl ionic liquid.

According to an embodiment of the invention, in step (1), the ionic liquid has a purity above 90%, for example above 95%.

According to the embodiment of the present invention, in the step (1), the light scattering medium may be first dispersed in a poor solvent of the light scattering medium to obtain a suspension of the light scattering medium. Wherein the poor solvent may be selected from good solvents and/or co-solvents of the cellulose membrane matrix, for example, at least one selected from N, N-dimethyl sulfoxide (DMSO), N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), Tetrahydrofuran (THF), acetone, chloroform, pyridine, N-methylpyrrolidone, and the above ionic liquids; exemplified is DMF. Wherein the mass-to-volume ratio of the light scattering medium to the poor solvent may be (0.2-4):1g/mL, such as (0.5-3):1g/mL, illustratively 0.67:1g/mL, 0.1g/mL, 0.13g/mL, 0.27 g/mL.

According to an embodiment of the present invention, in step (1), the obtaining of the suspended state of the light scattering medium in the homogeneous solution may be obtained by: (a) selecting a substance (such as chitosan, chitin, starch, lignin and other polysaccharides) which is insoluble or not soluble (including insoluble or slightly soluble) in the ionic liquid as a light scattering medium; or, (b) using the solubility difference of cellulose at different temperatures, for example, heating and dissolving the cellulose membrane matrix in the ionic liquid to obtain a uniform solution; and after cooling, adding cellulose or cellulose derivatives which are the same as or different from the cellulose membrane matrix into the homogeneous solution as a light scattering medium, and suspending and dispersing the light scattering medium in the homogeneous solution.

According to an embodiment of the present invention, in the step (2), the film formation may be performed by a film formation method known in the art, such as a doctor blade film, an extrusion film, a casting film or a calendering film; preferably, the solution system is required to be degassed of air bubbles prior to film formation. Illustratively, it may be selected from a doctor blade, such as using a doctor blade known in the art, for example a doctor blade having a thickness of 1000 μm.

According to an embodiment of the present invention, in the step (2), the coagulation bath may be selected from at least one of water, alcohol, an ionic liquid aqueous solution; for example, the alcohol is selected from at least one of methanol, ethanol, propanol, and isobutanol; for example, the aqueous ionic liquid solution is preferably an aqueous solution of an ionic liquid that dissolves cellulose, wherein the mass fraction of the ionic liquid is greater than 0 and not more than 60%, for example 10-40%. Further, the regeneration process in the coagulation bath may include processes of coagulation, soaking and washing of cellulose, for example, the coagulation, soaking and washing may be sequentially performed in different coagulation baths of ionic liquid aqueous solution, water, alcohol, and the like.

According to the embodiment of the invention, in the step (2), the regeneration is to place the film layer obtained by film formation in a coagulating bath for regeneration to obtain the cellulose gel film.

According to an embodiment of the present invention, in the step (2), the drying manner may be a drying manner known in the art, such as natural drying, normal temperature drying, heat drying or vacuum drying.

According to an exemplary embodiment of the invention, the method comprises the steps of:

1) dispersing chitosan in DMF to obtain chitosan suspension;

2) stirring and mixing the chitosan suspension, the ionic liquid and the cellulose membrane matrix at 60-100 ℃;

3) and 2) regenerating the mixture system obtained in the step 2) through film forming and coagulating bath to obtain a cellulose gel film, and drying the cellulose gel film to obtain the cellulose film.

Preferably, the method comprises the following steps:

1) dispersing chitosan in DMF to obtain chitosan suspension; then dropwise adding the chitosan suspension into ionic liquid with the temperature of 60-100 ℃ (such as 70-90 ℃, exemplary 80 ℃) to obtain a chitosan/ionic liquid mixed solution;

2) maintaining the temperature of the mixed solution, and completely dissolving the cellulose membrane matrix in the mixed solution;

3) and 2) regenerating the mixture system obtained in the step 2) through film forming and coagulating bath to obtain a cellulose gel film, and drying the cellulose gel film to obtain the cellulose film. Wherein the preparation process of the chitosan suspension comprises the following steps: dispersing chitosan powder in DMF at normal temperature, and magnetically stirring for 5-20 min (e.g. 10 min) to obtain chitosan suspension.

Wherein the dropwise addition is performed under stirring, and after the completion of the dropwise addition of the chitosan suspension, the stirring is continued for 5 to 20 minutes (e.g., 10 minutes).

Wherein the dissolving operation of the cellulose membrane substrate in the mixed solution comprises: dissolving for 1-5h (e.g. 3h) under stirring at 200-500r/min (e.g. 350 r/min).

According to another exemplary embodiment of the present invention, the method comprises the steps of:

1) heating and stirring a cellulose membrane matrix in ionic liquid until the cellulose membrane matrix is completely dissolved, and then cooling;

2) dispersing microcrystalline cellulose in the solution in step 1);

3) and (3) regenerating the mixture system obtained in the step 2) through a film scraping and coagulating bath to obtain a cellulose gel film, and drying the cellulose gel film to obtain the cellulose film.

Preferably, the method comprises the following steps:

1) heating and stirring the cellulose membrane matrix in ionic liquid until the cellulose membrane matrix is completely dissolved, and then cooling to room temperature;

preferably, the cotton pulp cellulose is added to the ionic liquid, heated to 60-100 ℃ (e.g., 70-90 ℃, exemplary 80 ℃) and dissolved for 1-5h (e.g., 2h) under stirring conditions of 200-;

2) dispersing microcrystalline cellulose in DMF to obtain microcrystalline cellulose suspension; dropwise adding the microcrystalline cellulose suspension into the solution obtained in the step 1) at room temperature;

3) and 2) regenerating the mixture system obtained in the step 2) through a film scraping and coagulating bath to obtain a cellulose gel film, and drying the cellulose gel film to obtain the cellulose film.

Wherein the preparation process of the microcrystalline cellulose suspension comprises the following steps: at normal temperature, the microcrystalline cellulose is dispersed in DMF, and the microcrystalline cellulose suspension is obtained after magnetic stirring for 5-20 minutes (such as 10 minutes).

Wherein the dropwise addition is carried out under stirring conditions, and after the completion of the dropwise addition of the microcrystalline cellulose suspension, the stirring is continued for 10 to 50 minutes (e.g., 30 minutes).

The present invention provides a cellulose film produced by the above method.

The invention also provides application of the cellulose membrane in the fields of outdoor displays, solar cells and the like.

The invention has the beneficial effects that:

the invention provides a haze-adjustable high-transmittance cellulose film and a preparation method and application thereof. According to the invention, by utilizing the solubility difference of different substances in the same system, substances with poor solubility (such as chitosan which is a purely natural substance is creatively added) are used as light scattering media in the cellulose membrane, and the surface roughness of the cellulose membrane is increased, so that the preparation of the cellulose membrane with high haze and high light transmittance is realized. Or, the cellulose which is not completely dissolved is used as a light scattering medium in the cellulose membrane by utilizing different dissolution degrees of the cellulose under different conditions (such as temperature), and the surface roughness of the cellulose membrane is increased, so that the preparation of the high-haze high-light-transmittance cellulose thin film is realized. The high-haze high-transmittance cellulose membrane is formed by regenerating in water to obtain a gel membrane after forming a membrane by using a cellulose membrane matrix ionic liquid solution, and then drying the gel membrane. The adjustable haze of the cellulose membrane is realized by changing the parameters of the particle size, the mass fraction and the like of the light scattering medium in the cellulose membrane matrix ionic liquid. The method has simple process and is suitable for roll-to-roll production.

The pure natural cellulose-based material with high light transmittance and high haze is obtained, the light transmittance is more than 75%, and the haze is adjustable between 5% and 95%.

Drawings

FIG. 1 is an SEM image of the cellulose film obtained in example 4: (a) is a surface topography picture, and (b) is a film section picture.

FIG. 2 is an SEM photograph of the cellulose film obtained in example 5: (a) is a surface topography picture, and (b) is a film section picture.

FIG. 3 is an SEM image of the cellulose film obtained in example 6: (a) is a surface topography picture, and (b) is a film section picture.

FIG. 4 is an SEM image of the cellulose film obtained in example 8: (a) is a surface topography picture, and (b) is a film section picture.

FIG. 5 is a graph showing the light transmittance of the cellulose films obtained in examples 1 to 5.

FIG. 6 is a haze chart of cellulose films obtained in examples 1 to 9.

Fig. 7 is an SEM image of the chitosan powder sieved in preparation example 1: (a)200 meshes and (b)1800 meshes.

Fig. 8 is a polarization microscope photograph of chitosan powder in ionic liquid of preparation example 1: (a1) and (a2) is 200 mesh chitosan powder, (b1) and (b2) is 1800 mesh chitosan powder.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

The light transmittance and haze of the cellulose film in the following examples were measured according to the integrating sphere method in GB/T2410-.

Preparation example 1

Screening chitosan powder:

and (3) grinding the chitosan powder in a ball mill for 8 hours, and sieving by using a standard sieve to obtain the chitosan powder with 200 meshes, 300 meshes and 1800 meshes respectively.

Fig. 7 is SEM images of the chitosan powder of 200 mesh (a) and 1800 mesh (b) sieved in preparation example 1, and fig. 8 is a polarization microscope photograph of the chitosan powder of 200 mesh (a1-a2) and 1800 mesh (b1-b2) in a cotton pulp cellulose/ionic liquid, in which the mass ratio of chitosan to cotton pulp cellulose/ionic liquid is 1: 4: 100. as can be seen from fig. 7 and 8, the chitosan powder after sieving has a uniform particle size and still maintains the original crystal form in the ionic liquid.

Preparation example 2

Sieving of microcrystalline cellulose powder:

and (3) grinding the microcrystalline cellulose powder in a ball mill for 8 hours, and sieving by using a standard sieve to obtain chitosan powder with 200 meshes, 300 meshes and 1800 meshes respectively.

Example 1

With the chitosan powder of 1800 mesh in preparation example 1 as an optical dispersion medium, 0.1g of chitosan powder was dispersed in 3mL of DMF solution under magnetic stirring at 500r/min to obtain a chitosan suspension. Then the chitosan suspension is added dropwise into 35g of AmimCl ionic liquid and stirred for 10min at 80 ℃ and 350 r/min. Adding 1.6g of cotton pulp cellulose into AmimCl ionic liquid dispersed with chitosan powder, and continuously stirring and dissolving at 80 ℃ and 350r/min for 3h until the cotton pulp cellulose is completely dissolved. The obtained mixture system was degassed of air bubbles, then knife-coated with a 1000 μm doctor blade and regenerated in water to obtain a cellulose gel film. And after the ionic liquid in the cellulose gel film is completely replaced by water, drying the cellulose gel film in the air at normal temperature and normal pressure to obtain the cellulose film with high haze and high light transmittance.

As shown in fig. 5, the cellulose film obtained in this example had a light transmittance of 89%.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 8%.

Example 2

The present example differs from example 1 in that: the dosage of chitosan powder is 0.2 g. The cellulose film with high haze and high light transmittance is obtained.

As shown in fig. 5, the cellulose film obtained in this example had a light transmittance of 85%.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 55%.

Example 3

This example differs from example 1 in that: the dosage of chitosan powder is 0.3 g. The cellulose film with high haze and high light transmittance is obtained.

As shown in fig. 5, the cellulose film obtained in this example had a light transmittance of 88%.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 63%.

Example 4

This example differs from example 1 in that: the amount of chitosan powder was 0.4 g. The morphology of the obtained cellulose film with high haze and high light transmittance is shown in figure 1, a large number of microstructures appear on the surface of the cellulose film, and the uneven structures improve the light scattering capacity of the cellulose film.

As shown in fig. 5, the cellulose film obtained in this example had a light transmittance of 87%.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 65%.

Example 5

This example differs from example 1 in that: the amount of chitosan powder was 0.8 g. The obtained cellulose film with high haze and high light transmittance has the appearance shown in fig. 2, the microstructure of the surface of the cellulose film is increased, and the rougher surface further improves the light scattering capacity of the cellulose film.

As shown in fig. 5, the cellulose film obtained in this example had a light transmittance of 86%.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 79%.

Example 6

This example differs from example 2 in that: the particle size of the chitosan powder is 200 meshes. The morphology of the obtained cellulose film with high haze and high light transmittance is shown in fig. 3, the structure size of the surface of the cellulose film is increased, and the roughness is reduced compared with that of example 4, so that the light scattering ability of the cellulose film is reduced.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 42%.

Example 7

This example differs from example 4 in that: the particle size of the chitosan powder is 200 meshes.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 58%.

Example 8

This example differs from example 5 in that: the particle size of the chitosan powder is 200 meshes. The morphology of the obtained cellulose film with high haze and high light transmittance is shown in fig. 4, the structure size of the surface of the cellulose film is larger, the roughness is reduced compared with example 5, but the roughness is improved compared with example 6, and therefore the light scattering ability of the cellulose film is between example 5 and example 6.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 71%.

Example 9

This example differs from example 6 in that: the particle size of the chitosan powder is 300 meshes.

As shown in fig. 6, the haze of the cellulose film obtained in this example was 35%.

Example 10

This example differs from example 1 in that: the dosage of the chitosan powder is 0.8g, the cellulose hydrogel film is soaked in ethanol, and after the water in the cellulose hydrogel film is completely replaced, the cellulose hydrogel film is dried in a drying oven at 70 ℃ to obtain the cellulose film with high haze and high light transmittance, wherein the average haze is more than 82%.

Example 11

Taking 1.6g of cotton pulp cellulose, adding the cotton pulp cellulose into the AmimCl ionic liquid, stirring and dissolving for 2 hours at the temperature of 80 ℃ and at the speed of 350r/min, and then cooling to room temperature to obtain a uniform solution of the cotton pulp cellulose/AmimCl ionic liquid. With microcrystalline cellulose powder having a mesh size of 1800 mesh in preparation example 2 as a light dispersion medium, 0.4g of microcrystalline cellulose powder was dispersed in 3mL of DMF solution under magnetic stirring at 500 r/min. Then, the microcrystalline cellulose suspension is dripped into the obtained uniform solution of the cotton pulp cellulose/AmimCl ionic liquid, and is stirred for 30min under the condition of 300 r/min. And removing bubbles from the uniformly dispersed mixture system, carrying out blade coating by using a 1000-micron film scraper, and regenerating in water to obtain the cellulose gel film. And after the ionic liquid in the cellulose gel film is completely replaced by water, drying the cellulose gel film in the air at normal temperature and normal pressure to obtain the cellulose film with high haze and high light transmittance.

Example 12

This example differs from example 1 in that: the light dispersion medium is changed into lignin.

Those skilled in the art can expect that a cellulose film with high haze and high light transmittance can be obtained when the light scattering medium, the cellulose film matrix material, the ionic liquid, and the like in the above embodiments are replaced with other substances listed in the summary of the invention.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a cellulose film, comprising the steps of:

the light scattering medium is obtained in a suspension state in a uniform solution by the following method: (a) selecting a substance which is insoluble or not soluble in the ionic liquid as a light scattering medium; or (b) heating and dissolving the cellulose membrane matrix in the ionic liquid by utilizing the solubility difference of the cellulose at different temperatures to obtain a uniform solution; after cooling, adding cellulose or cellulose derivatives which are the same as or different from the cellulose membrane matrix into the homogeneous solution as a light scattering medium, and suspending and dispersing the light scattering medium in the homogeneous solution;

the light scattering medium is added to the homogeneous solution of cellulose membrane matrix/ionic liquid in the form of a suspension thereof, which is obtained as follows: dispersing a light scattering medium in a poor solvent for the light scattering medium;

the mass ratio of the cellulose membrane matrix to the light scattering medium is 1 (0.02-0.75);

the particle size of the light scattering medium is 100-2000 meshes;

(2) after the solution system in the step (1) is formed into a film, placing the film in a coagulating bath for regeneration to obtain a cellulose gel film, and drying the cellulose gel film to obtain the cellulose film;

the cellulose film comprises: the light scattering medium is at least one of biomass and a biomass derivative.

2. The method according to claim 1, wherein the light-scattering medium is at least one selected from the group consisting of chitosan, chitin, starch, lignin, cellulose esters, cellulose ethers, and microcrystalline cellulose.

3. The production method according to claim 2, characterized in that the cellulose ester is at least one selected from the group consisting of cellulose acetate, cellulose acetate butyrate, cellulose propionate, cellulose butyrate, cellulose nitrate, cellulose sulfate, cellulose benzoate and cellulose cinnamate,

and/or the cellulose ether is selected from at least one of methyl cellulose, ethyl cellulose, carboxymethyl cellulose and hydroxyethyl cellulose,

and/or the lignin is selected from at least one of alkali lignin, sulfate lignin, solvent lignin, acid hydrolysis lignin and enzyme method lignin.

4. The method according to claim 1, wherein the cellulose film substrate is made of at least one of cotton pulp cellulose, microcrystalline cellulose, wood pulp, bamboo pulp, absorbent cotton, bagasse, wood, and cellulose obtained from plant straw.

5. The method of claim 1, wherein the insoluble or poorly soluble substance is chitosan, chitin, starch, or lignin.

6. The production method according to any one of claims 1 to 5, wherein in the step (1), the mass ratio of the cellulose membrane matrix to the ionic liquid in the homogeneous solution of cellulose membrane matrix/ionic liquid is (0.01-0.1): 1.

7. The method according to claim 1, wherein in step (1), the ionic liquid is an organic molten salt having a melting point of less than 100 ℃ and formed by an imidazole or pyridine type cation and an anion; the ionic liquid is selected from ionic liquids which can dissolve the cellulose membrane matrix material but can not dissolve or not easily dissolve the light scattering medium at the same temperature or can not dissolve or not easily dissolve the light scattering medium through temperature difference.

8. The method according to claim 7, wherein the cation of the ionic liquid is at least one selected from the group consisting of: 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-allyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, N-ethylpyridinium cation, N-butylpyridinium cation, N-hexylpyridineium cation;

the anion of the ionic liquid is selected from at least one of the following: chloride, bromide, formate, acetate, propionate, butyrate, and methyl phosphate ions.

9. The method of claim 7, wherein the ionic liquid is selected from the group consisting of 1-allyl-3-methylimidazole chloride ionic liquids.

10. The method according to any one of claims 7 to 9, wherein the ionic liquid has a purity of 90% or more.

11. The production method according to claim 1 or 5, wherein in the step (1), the poor solvent is selected from a good solvent and/or a co-solvent for a cellulose film substrate: at least one of N, N-dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide, tetrahydrofuran, acetone, chloroform, pyridine, N-methylpyrrolidone, and an ionic liquid in the method according to claim 8 or 9.

12. The method according to claim 11, wherein the mass-to-volume ratio of the light-scattering medium to the poor solvent is (0.2-4):1 g/mL.

13. The production method according to claim 1, wherein in the step (2), the film formation is a wiped film, an extruded film, a cast film, or a calendered film.

14. The method according to claim 1, wherein the coagulation bath is at least one selected from water, alcohol, and an ionic liquid aqueous solution.

15. The method according to claim 1 or 14, wherein the regeneration in the coagulation bath comprises coagulation, soaking and washing of cellulose.

16. The production method according to claim 1, wherein the regeneration is carried out by placing the film layer obtained by film formation in a coagulation bath to regenerate a cellulose gel film.

17. The preparation method according to claim 1, wherein the drying manner is natural drying, normal temperature drying, heat drying or vacuum drying.

18. The method for preparing according to claim 1, characterized in that it comprises the following steps:

1) dispersing chitosan in N, N-dimethylformamide to obtain a chitosan suspension;

3) the mixture system obtained in the step 2) is subjected to film forming and coagulation bath regeneration to obtain a cellulose gel film, and the cellulose gel film is dried to obtain the cellulose film;

alternatively, the method comprises the steps of:

2) dispersing microcrystalline cellulose in the solution in step 1);

19. The preparation method according to claim 1, wherein the cellulose film has a light transmittance of 75% or more, and/or a haze of 5 to 95%, and/or a thickness of 20 to 80 μm.

20. The method according to claim 1 or 19, wherein the cellulose film is used in the field of outdoor displays or solar cells.