Cellulose solvent, cellulose dissolving method and cellulose solution
阅读说明：本技术 一种纤维素溶剂、纤维素溶解方法及纤维素溶液 (Cellulose solvent, cellulose dissolving method and cellulose solution ) 是由 江元平 张云秀 黄芳 温霞 刘恋 余姝慧 李嘉莉 尚宁 王健翔 于 2021-10-13 设计创作，主要内容包括：本发明属于天然高分子材料领域,具体涉及一种纤维素溶剂、纤维素溶解方法、纤维素溶液及其应用。本发明提供一种能够常温下快速溶解纤维素的溶剂,所述溶剂为N,N,N-三甲基-1-金刚烷基氢氧化铵水溶液或其与其他烷基氢氧化铵水溶液的混合溶剂。本发明提供一种利用用于溶解纤维素的新型溶剂——环烷基氢氧化铵,利用其无需冷冻溶解即可实现常温下快速溶解纤维素,所得纤维素溶液能再生制备纤维素材料。(The invention belongs to the field of natural polymer materials, and particularly relates to a cellulose solvent, a cellulose dissolving method, a cellulose solution and application thereof. The invention provides a solvent capable of quickly dissolving cellulose at normal temperature, which is an aqueous solution of N, N, N-trimethyl-1-adamantyl ammonium hydroxide or a mixed solvent of the aqueous solution of N, N, N-trimethyl-1-adamantyl ammonium hydroxide and other aqueous solutions of alkyl ammonium hydroxide. The invention provides a method for quickly dissolving cellulose at normal temperature by using a novel solvent for dissolving cellulose, namely cycloalkyl ammonium hydroxide, without freezing and dissolving, and the obtained cellulose solution can be regenerated to prepare a cellulose material.)
1. The solvent capable of quickly dissolving cellulose at normal temperature is characterized in that the solvent is N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution or a mixed solvent of the N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution and other alkyl ammonium hydroxide aqueous solutions.
2. The solvent capable of rapidly dissolving cellulose at normal temperature according to claim 1, wherein said other alkyl ammonium hydroxide is selected from the group consisting of: at least one of triethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, or triethylbenzylammonium hydroxide.
3. The solvent capable of rapidly dissolving cellulose at normal temperature according to claim 1 or 2, wherein the mass ratio of N, N-trimethyl-1-adamantyl ammonium hydroxide to other alkyl ammonium hydroxides in the mixed solvent is: 5: 95-95: 5.
4. the solvent capable of rapidly dissolving cellulose at ordinary temperature according to any one of claims 1 to 3, wherein the cellulose has a molecular weight of 1.5 x 105Cellulose in the inner part.
5. A method for dissolving cellulose, characterized in that it is carried out in one of the following ways:
the first method is as follows: freezing cellulose and a solvent with the concentration of 0.5-2.5M at-25 ℃ to-5 ℃ for at least 4h, and then unfreezing at room temperature to obtain a uniform and transparent cellulose solution;
the second method comprises the following steps: uniformly mixing cellulose and a solvent with the concentration of 0.5-2.5M at 0-60 ℃ to obtain a uniform and transparent cellulose solution;
wherein the solvent is N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution or a mixed solvent of the N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution and other alkyl ammonium hydroxide aqueous solutions.
6. The method of dissolving cellulose according to claim 5, wherein said other alkyl ammonium hydroxides are selected from the group consisting of: at least one of triethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, or triethylbenzylammonium hydroxide;
further, in the mixed solvent, the mass ratio of the N, N, N-trimethyl-1-adamantyl ammonium hydroxide to other alkyl ammonium hydroxides is as follows: 5: 95-95: 5.
7. the cellulose dissolving method according to claim 5 or 6, wherein in the second mode, the cellulose and the solvent are mixed by stirring or ultrasonic method for 5-10 min to realize uniform mixing;
further, in the second mode, the temperature for uniformly mixing the cellulose and the solvent is 10-30 ℃;
further, the cellulose has a molecular weight of 1.5X 105Cellulose in the inner part.
8. The method for dissolving cellulose according to any one of claims 5 to 7, wherein the cellulose solution is obtained in which the cellulose content is 0.1 to 20% by mass.
9. A cellulose solution obtained by the method according to any one of claims 5 to 8.
10. Use of the cellulose solution according to claim 9 in regenerated cellulose membranes, regenerated cellulose gels or cellulose spinning.
Technical Field
The invention belongs to the field of natural polymer materials, and particularly relates to a cellulose solvent, a cellulose dissolving method, a cellulose solution and application thereof.
Background
The cellulose is used as renewable natural polymer with the widest source on the earth, and has the characteristics of environmental friendliness and energy conservation. Due to its unique characteristics, such as biodegradability, excellent mechanical properties and renewability, cellulosic materials have broad application prospects in packaging materials and other applications.
Films, multifilaments, viscose, rayon and the like which dissolve regenerated cellulose have been established as commercial products. However, the traditional viscose production process discharges poisonous CS2Waste water and heavy metals, leading to serious environmental problems (j. macro. sci. -rev. macro. chem.,1980, C18, 1). In recent decades, a series of low-toxicity and environmentally friendly cellulose solvent systems, such as n-methylmorpholine-n-oxide (NMMO) (U.S. patent4302252,1981), cuprammonium solutions, ionic liquids (CN1596282A) and alkali/urea solutions (00114486.3; 03128386.1; 200310111447.8; 200310111567.8) have been known. Other related dissolution methods reported in succession also have their limitations: if the production route is complex, harmful byproducts are generated in the production process; or require rigorous solvent recovery, etc. These current production strategies still need further improvement to meet the demands of industrial applications.
Disclosure of Invention
In order to solve the problems, the invention provides a novel solvent for dissolving cellulose, namely naphthenic ammonium hydroxide, by which the cellulose can be quickly dissolved at normal temperature without being frozen and dissolved, and the obtained cellulose solution can be regenerated to prepare a cellulose material.
The technical scheme of the invention is as follows:
the first technical problem to be solved by the invention is to provide a solvent capable of rapidly dissolving cellulose at normal temperature, wherein the solvent is an aqueous solution of N, N, N-trimethyl-1-adamantyl ammonium hydroxide or a mixed solvent of the aqueous solution of N, N, N-trimethyl-1-adamantyl ammonium hydroxide and an aqueous solution of alkyl ammonium hydroxide.
Further, the other alkyl ammonium hydroxides are selected from: at least one of triethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, or triethylbenzylammonium hydroxide.
Further, in the mixed solvent, the mass ratio of the N, N, N-trimethyl-1-adamantyl ammonium hydroxide to other alkyl ammonium hydroxides is as follows: 5: 95-95: 5.
further, the cellulose has a molecular weight of 1.5X 105Cellulose in the inner part.
A second technical problem to be solved by the present invention is to provide a method for dissolving cellulose, which comprises one of the following steps:
the first method is as follows: freezing cellulose and a solvent with the concentration of 0.5-2.5M at-25 ℃ to-5 ℃ for at least 4h, and then unfreezing at room temperature to obtain a uniform and transparent cellulose solution;
the second method comprises the following steps: uniformly mixing cellulose and a solvent with the concentration of 0.5-2.5M at 0-60 ℃ to obtain a uniform and transparent cellulose solution;
wherein the solvent is N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution or a mixed solvent of the N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution and other alkyl ammonium hydroxide aqueous solutions.
Further, in the above dissolving method, the other alkylammonium hydroxides are selected from: at least one of triethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, or triethylbenzylammonium hydroxide;
further, in the above dissolving method, the mass ratio of N, N-trimethyl-1-adamantyl ammonium hydroxide to other alkyl ammonium hydroxides in the mixed solvent is: 5: 95-95: 5.
further, in the dissolving method, in the second mode, the cellulose and the solvent are mixed by stirring or ultrasonic method for 5-10 min to realize uniform mixing.
Further, in the above dissolving method, in the second mode, the temperature at which the cellulose and the solvent are uniformly mixed is 10 to 30 ℃.
Further, in the above dissolving method, the cellulose has a molecular weight of 1.5X 105Cellulose in the inner part.
Further, in the dissolving method, the mass content of the cellulose in the obtained cellulose solution is 0.1-20%.
The fourth technical problem to be solved by the present invention is to indicate the use of the above cellulose solution in regenerated cellulose membranes, regenerated cellulose gels or cellulose spinning.
The invention has the beneficial effects that:
1. the invention takes N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution or mixed solvent of the N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution and alkyl ammonium hydroxide aqueous solution as a solvent system, and can realize rapid dissolution of cellulose at normal temperature; the solvent system is simple, the operability is strong, and the waste liquid is easy to recycle.
2. The invention can use an ultrasonic mixing method, can remove bubbles in the process of assisting the dispersion and dissolution of the cellulose and simplifies the process flow.
3. The invention can also dissolve cellulose without low temperature-freezing at normal temperature, thereby simplifying operation flow and process difficulty and saving production cost.
Description of the drawings:
FIG. 1 is a photograph of the cellulose solution obtained in example 1.
FIG. 2 is a photograph of the cellulose solution obtained in example 2.
FIG. 3 is a photograph of the cellulose solution obtained in example 3.
FIG. 4 is a photograph showing a cellulose film obtained in example 2, in which a 5 wt% cellulose solution was precipitated in water as a coagulation bath, printed with a logo, and it can be seen that: the cellulose in example 2 dissolves well in the solvent, and the film formed has good uniformity and transparency.
FIG. 5 is a photograph showing a cellulose film obtained by precipitating the 5 wt% cellulose solution obtained in example 3 in water as a coagulation bath, which is printed with a logo, and it can be seen that: the cellulose in example 3 dissolves well in the solvent, and the film formed has good uniformity and transparency.
FIG. 6 is a graph showing the effect of dissolving 1 wt% of cellulose obtained in comparative example 1 in cetyl trimethylammonium hydroxide, which shows that the solvent has no significant effect of dissolving cellulose at room temperature.
Detailed Description
The following examples are given to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention.
Example 1
5 parts of molecular weight about 0.4 x 105The microcrystalline cellulose is added into 95 parts of 1.5M N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution, and the mixture is rapidly shaken or ultrasonically treated for about 5min at the normal temperature of 30 ℃ to prepare colorless transparent solution with the cellulose concentration of 5 wt%.
Example 2
5 parts of the mixture are mixed to obtain a mixture with a molecular weight of about 1.0 x 105The cotton pulp is added into 95 parts of 1.5M N, N, N-trimethyl-1-adamantyl ammonium hydroxide aqueous solution, and is vibrated or ultrasonically treated for about 5min at normal temperature to prepare colorless transparent solution with the cellulose concentration of 5 wt%.
Example 3
Taking 5 parts of molecular weight of about 1.3 x 105The cellulose powder was added to 95 parts of 1.5M aqueous solution of N, N, N-trimethyl-1-adamantyl ammonium hydroxide, shaken well, frozen at-15 ℃ for 8 hours, and then thawed at room temperature to obtain a colorless transparent solution having a cellulose concentration of 5 wt%.
Example 4
5 wt% of the molecular weight obtained in example 3 was 1.3 x 105The cellulose solution is spread on a glass plate, and then water is used as a coagulating bath for precipitation, so that the cellulose film material can be prepared.
Comparative example 1
Will 1The molecular weight of the fraction is about 0.4 x 105The microcrystalline cellulose is added into 99 parts of 1.5M hexadecyl trimethyl ammonium hydroxide aqueous solution, and the mixture is rapidly vibrated or ultrasonically treated for about 5min at normal temperature, so that the cellulose is not obviously dissolved.