A process for preparing cellulose nanocrystal dispersion based on controllable dissolution

Abstract

The invention discloses a process method for preparing cellulose nanocrystal dispersion liquid based on controllable dissolution. The cellulose solvent is used as an organic alkali / urea / water mixed system, the concentration of organic alkali is 30-45wt%, and the concentration of urea is 1-24wt. %, the rest is water, and the cellulose concentration is 0.1~35.0wt%. Based on the principle of regulating the amphiphilic properties of the cellulose solvent and inducing it to produce differential solubility for regions with different crystallization degrees of cellulose, the present invention proposes a controllable and selective dissolution technology for cellulose. Controllable and selective dissolution of crystalline and semi-crystalline regions to prepare a cellulose nanocrystal dispersion, and then obtain pure cellulose nanocrystals through further conventional processing. The prepared cellulose nanocrystal has the chemical structure of natural cellulose. The invention has simple process, mild conditions, low equipment requirements, no pollution to the environment in the preparation process, is suitable for industrial production, and has wide application prospects.

Description

Technical field [0001] The invention belongs to the technical field of cellulose nanocrystalline products, and particularly relates to a method for preparing a cellulose nanocrystalline dispersion based on controllable dissolution. Background technique [0002] As the most abundant renewable resource in nature, cellulose is widely distributed worldwide and the total amount is huge. In recent years, as the total amount of non-renewable fossil resources such as petroleum has decreased, the importance of renewable resources such as cellulose has become increasingly significant. It has many excellent properties, such as excellent mechanical properties, good biocompatibility, biodegradability, high specific surface area and abundant active sites. The processing of cellulose nanocrystals from natural cellulose is a high-value cellulose utilization form. It has been widely used in the fields of food, medicine, cosmetics, and composite materials. It has also been used in supercapacitors...

AI Technical Summary

Problems solved by technology

The acid hydrolysis method can usually obtain cellulose nanocrystals with a diameter of 10-30nm and a length of 100-300nm, but it needs to consume a large amount of acid-base reagents, the production efficiency is low, and the preparation and post-treatment process is relatively complicated and cumbersome, which is harmful to the equipment. Corrosion resistance also puts forward higher requirements

The TEMPO oxidation method can usually obtain cellulose nanocrystals with a diameter of about 5-10nm and a relatively large aspect ratio, but it also has the problem of cumbersome preparation and post-treatment processes, and the prepared cellulose nanocrystals are a derivatized fiber white

Although the physical and mechanical method has a relatively simple process, it puts forward higher requirements for mechanical equipment, and usually only cellulose microfibers can be obtained, and the scale is larger than that of cellulose nanocrystals.

Although the microbial fermentation method can prepare nanocellulose fibers with nanoscale diameter and high aspect ratio, usually these fibers are not easy to disperse due to a large amount of entanglement, and the preparation conditions are harsh and the cycle is long.

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