阅读说明：本技术 一种纳米纤维素成膜的方法 (Method for forming film by nano-cellulose ) 是由 路芳 司晓勤 卢锐 于 2019-04-09 设计创作，主要内容包括：本申请公开了一种纳米纤维素成膜的方法,该方法至少包括以下步骤：(1)将纤维素原料吸水溶胀后,与有机溶剂1混合,然后分离得到固体,所述有机溶剂1置换出纤维素中的水；(2)将所述分离得到的固体与有机溶剂2混合,陈化得到铸膜液,所述有机溶剂2均匀分散纤维素；(3)将所述铸膜液置于玻璃板上刮制膜,即得纳米纤维素膜。本发明制备的纳米纤维素膜具有良好的亲水性和力学性能,并且操作过程简单,在化妆品、医药和食品等行业具有广泛的应用前景。(The application discloses a method for forming a film by using nanocellulose, which at least comprises the following steps: (1) after absorbing water and swelling, mixing the cellulose raw material with an organic solvent 1, and then separating to obtain a solid, wherein the organic solvent 1 replaces water in cellulose; (2) mixing the solid obtained by separation with an organic solvent 2, and aging to obtain a membrane casting solution, wherein the organic solvent 2 uniformly disperses cellulose; (3) and placing the membrane casting solution on a glass plate to scrape a membrane, thus obtaining the nano cellulose membrane. The nano cellulose membrane prepared by the method has good hydrophilicity and mechanical property, is simple in operation process, and has wide application prospect in industries such as cosmetics, medicines, foods and the like.)

1. A method for forming a film from nanocellulose, characterized in that it comprises at least the following steps:

(1) after absorbing water and swelling, mixing the cellulose raw material with an organic solvent 1, and then separating to obtain a solid, wherein the organic solvent 1 replaces water in cellulose;

(2) mixing the solid obtained by separation with an organic solvent 2, and aging to obtain a membrane casting solution, wherein the organic solvent 2 uniformly disperses cellulose;

(3) and placing the membrane casting solution on a glass plate to scrape a membrane, thus obtaining the nano cellulose membrane.

2. The method according to claim 1, characterized in that the particle size of the cellulosic raw material is between 1cm and 100 mesh;

preferably, the thickness of the nanocellulose membrane is between 0.001 and 0.6 cm.

3. The method according to claim 1, characterized in that the cellulosic raw material is derived from wood chips and/or straw;

the cellulose raw material is selected from at least one of cellulose pulp, nano-cellulose and microcrystalline cellulose;

preferably, the wood chips comprise at least one of pine, beech, birch;

the straw comprises at least one of corn straw and wheat straw.

4. The method of claim 1, wherein the step of swelling the cellulosic feedstock with water comprises mixing the cellulosic feedstock with water;

the mass-to-water volume ratio of the cellulose raw material is 1 g: (6-100) mL.

5. The method according to claim 1, wherein the organic solvent 1 comprises at least one of methanol, ethanol, and acetone;

preferably, the volume ratio of the mass of the cellulose raw material to the organic solvent 1 is 1 g: (6-100) mL.

6. The method according to claim 1, wherein the organic solvent 2 is at least one selected from the group consisting of a lithium chloride-N, N-dimethylacetamide mixed system, N-dimethylformamide, tetrahydrofuran, N-methylmorpholine-N-oxide, toluene, and chloroform;

preferably, the ratio of the mass of the cellulose raw material to the volume of the organic solvent 2 is 1 g: (6-100) mL;

preferably, the mass concentration of cellulose in the mixture obtained after mixing the separated solid with the organic solvent 2 is 3% to 20%.

7. The method according to claim 1, wherein the step of scraping the membrane on a glass plate comprises immersing the glass plate together with the membrane in water.

8. A nanocellulose membrane, characterized in that it is prepared by the method of any one of claims 1 to 7;

the nanocellulose membrane consists of uniform nanocellulose filaments.

9. Use of a nanocellulose membrane prepared according to the method of any one of claims 1 to 7 or according to claim 8 in the field of daily chemicals.

10. Use of a nanocellulose membrane as described in claim 8 or prepared by a process as described in any one of claims 1 to 7 in a mask product.

Technical Field

The application relates to a method for forming a nano-cellulose film, belonging to the technical field of preparation of polymer films.

Background

The plant cellulose is the most abundant renewable resource on the earth, accounts for about 40-50% of the total mass of biomass, is used as a material which is wide in source, environment-friendly, biocompatible and biodegradable, can protect the environment by fully utilizing the cellulose, can save limited petroleum resources, and has important practical significance. From the chemical structure, cellulose is a chain-shaped high molecular compound formed by connecting D-glucose through glycosidic bonds, each glucose ring contains 3 hydroxyl groups, and the cellulose has good hydrophilicity, but because the high molecular chains have strong intramolecular and intermolecular hydrogen bonds, the cellulose is difficult to dissolve and cannot be melted, and the macroscopic stable physical and chemical properties greatly limit the wide application of the cellulose. Therefore, conventionally, cellulose derivative films are prepared by converting cellulose into its derivative by a chemical modification method and then processing the resulting film to form a film, for example, converting cellulose into a derivative such as cellulose ether or ester. However, these derivatization treatments narrow the application range of the cellulose membrane and limit the application conditions. For example, cellulose acetate films prepared further after cellulose esterification are easy to hydrolyze and have weak biological erosion resistance, so that strict requirements are imposed on the application range of the pH value in the using process. In addition, the chemical modification of cellulose causes the problems of cellulose degradation, denaturation, reduction of polymerization degree and crystallinity, poor mechanical strength, weak acid and alkali resistance and the like, and has a serious environmental pollution problem in the production process. Therefore, the development of a method for directly preparing cellulose raw materials into cellulose films is crucial to the wide application of cellulose.

The invention provides a preparation method of nano-cellulose film forming, which comprises the steps of dispersing cellulose by using an organic solvent system to obtain a cellulose film casting solution, scraping a film on a glass plate, and preparing a corresponding cellulose film by using an immersion gel method. The process is simple to operate and environment-friendly, and greatly improves the effective utilization rate of the cellulose raw material in the biomass.

Disclosure of Invention

The invention provides a method for forming a film by using nanocellulose, which at least comprises the following steps: (1) after absorbing water and swelling, mixing the cellulose raw material with an organic solvent 1, and then separating to obtain a solid, wherein the organic solvent 1 replaces water in cellulose; (2) mixing the solid obtained by separation with an organic solvent 2, and aging to obtain a membrane casting solution, wherein the organic solvent 2 uniformly disperses cellulose; (3) and placing the membrane casting solution on a glass plate to scrape a membrane, thus obtaining the nano cellulose membrane.

In a preferred embodiment, the cellulose raw material is swollen in water for 0.1 to 24 hours, separated by suction filtration, dispersed in the organic solvent 1 to displace the water therein, and further separated by suction filtration to obtain a solid. Optionally, the organic solvent 1 is repeatedly subjected to dispersion displacement suction filtration for 1 to 8 times.

In a preferred embodiment, the separated solid is added into the organic solvent 2, stirred for 1-24h until the cellulose is fully dispersed to obtain a cellulose solution with the concentration of 3-20%, and kept stand for 1-48h for aging to obtain the casting solution.

In a preferred embodiment, the cast membrane liquid stream is placed on a smooth and clean glass plate, a membrane with a certain thickness is scraped on the clean glass plate by a scraper, and then the glass plate and the membrane are put into water together to obtain the cellulose membrane.

In a preferred embodiment, the particle size of the cellulosic feedstock is between 1cm and 100 mesh.

In a preferred embodiment, the thickness of the nanocellulose membrane is from 0.001 to 0.6 cm.

In a preferred embodiment, the cellulosic feedstock comprises cellulosic pulp of wood chips and/or straw comprising at least one of pine, beech or birch, and nanocellulose, microcrystalline cellulose and nanocellulose thereof, the straw comprising at least one of corn stover and wheat straw.

In a preferred embodiment, the step of swelling the cellulosic feedstock with water comprises mixing the cellulosic feedstock with water; the mass-to-water volume ratio of the cellulose raw material is 1 g: (6-100) mL.

In a preferred embodiment, the organic solvent 1 includes at least one of methanol, ethanol, and acetone.

In a preferred embodiment, the ratio of the mass of the cellulose raw material to the volume of the organic solvent 1 is 1 g: (6-100) mL.

In a preferred embodiment, the organic solvent 2 comprises at least one of lithium chloride (LiCl) -N, N-Dimethylacetamide (DMAC), N-Dimethylformamide (DMF), Tetrahydrofuran (THF), N-methylmorpholine-N-oxide (NMMO), chloroform and toluene, wherein the mass ratio of lithium chloride to N, N-dimethylacetamide (LiCl) -N, N-Dimethylacetamide (DMAC) system is 1 (2-50).

In a preferred embodiment, the ratio of the mass of the cellulose raw material to the volume of the organic solvent 2 is 1 g: (6-100) mL.

Preferably, the lower limit of the volume ratio range of the mass of the cellulose raw material to the organic solvent 2 can be selected from 1/100g^-1、1/90g.mL^-1、1/80g.mL^-1、1/70g.mL^-1、1/60g.mL^-1、1/50g.mL^-1Or 1/40g.mL^-1Preferably, the upper limit of the volume ratio range of the mass of the cellulose raw material to the organic solvent 2 can be selected from 1/35g^-1、1/30g.mL^-1、1/25g.mL^-1、1/20g.mL^-1、1/15g.mL^-1、1/10g.mL^-1Or 1/6g.mL^-1。

In a preferred embodiment, the mixture obtained after mixing the solid obtained by separation with the organic solvent 2 has a cellulose mass concentration of 3% to 20%.

Another aspect of the present invention provides a nanocellulose membrane, prepared by the above method.

Another aspect of the present invention provides the use of the nanocellulose membrane prepared according to the above method in the field of daily chemicals.

In a further aspect of the invention there is provided the use of a nanocellulose membrane prepared according to the above method in a mask product.

The beneficial effects that this application can produce include:

1) the invention solves the problems of hydrolysis, degradation, denaturation and the like in the process of modifying and film-forming the cellulose, and provides conditions for the wide application of the cellulose. When the cellulose membrane is used as a mask, the cellulose membrane has large adsorption capacity to water-based nutrient solution, and nutrient substances are not easy to lose;

2) the cellulose solution has better formability of the cellulose membrane, and the prepared cellulose membrane has good light transmittance and mechanical property.

3) The method takes the biomass cellulose as the raw material, has the characteristics of wide sources, low price, easy obtainment, environmental protection, degradability and the like of the raw material, and has short production period and simple process flow, and the prepared cellulose membrane has better application prospect.

Drawings

FIG. 1 shows a scanning electron micrograph of the nanocellulose film prepared in example 1.

Figure 2 shows the good fit of the nanocellulose membranes prepared in example 1 to the skin.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.