Clean preparation method of carboxymethyl nanocellulose material

Abstract

The invention relates to a clean preparation method of a carboxymethyl nanocellulose material. The clean preparation method is prepared by the following steps: pretreatment of nanocellulose raw materials, oxygen bleaching and pulping, continuous oxygen bleaching, bleaching, crushing and activation of the pulp, etherification, neutralization and purification and nanocrystallization. According to the clean preparation method, multiple straws and plant wastes are utilized as raw materials for clean pulping to prepare cellulose pulp and then prepare the carboxymethyl cellulose nanofiber, so that the range of raw materials for nanocellulose preparation is expanded, the process is simple and continuous, and environment-friendly and low cost effects are achieved, a new path for preparing the nanocellulose is opened up and wide prospect is provided for application of the nanocellulose. According to the clean preparation method, the cellulose can be used as the raw material to directly prepareand obtain functional nanocellulose fiber, the prepared modified nanocellulose contains carboxyl groups, has good degree of crystallinity, is small in crystalline grain and provides a good basis for later application of the product.

Description

technical field [0001] The invention belongs to the field of fine chemical industry, and in particular relates to a clean preparation method of carboxymethyl nanocellulose material. Background technique [0002] Nano-cellulose materials are nano-sized cellulose products obtained from cotton, wood, straw and other types of cellulose through acid hydrolysis, enzymatic hydrolysis, alkalization catalysis or mechanical shearing. In the prior art, according to different preparation methods, nanocellulose materials are mainly divided into two categories: Cellulose Nanohiskers (abbreviated as CNWs) and nanocellulose (Cellulose Nanofibrils, abbreviated as CNFs), each of which has its own advantages in different applications. own performance advantages. The manufacturing methods of nanocellulose materials reported at home and abroad mainly include: chemical methods, physical methods, biological methods and synthetic methods. Among them, the biological enzymatic hydrolysis method is ...

AI Technical Summary

Problems solved by technology

Chemical methods are usually treated with strong acids, such as hydrochloric acid, sulfuric acid or phosphoric acid, etc., which are difficult and costly to recover after acidolysis of cellulose, and can only be used in laboratories at present; physical methods, such as direct use of ultrasonic , homogenization, mechanical crushing and ball milling, etc., are extremely difficult to make cellulose reach the nanoscale, which makes it difficult to control the nanoscale of the product. At the same time, there are also problems such as high energy consumption caused by strong treatment, so they have not entered the application stage.

[0003] In addition, if the cellulose is nano-sized first, and then carboxymethylated or esterified, due to the disadvantages of easy agglomeration, difficult dispersion, difficult control of the derivatization process, and difficult collection of nano-cellulose in alkali and organic solvents, especially nano-cellulose It is more difficult to prepare cellulose ether ester mixed derivative materials, so to realize the etherification of nanocellulose, it must first be alkalized, and alkalization will greatly destroy the nanometer characteristics of nanocellulose. If etherification is achieved through chemical reactions, then It is more difficult to maintain the nano-morphology of cellulose, so it is difficult to directly prepare nano-cellulose with functional groups

[0004] At present, plant cellulose products such as wheat, corn, cotton stalks, bamboo, reed, and rice straw residues are rich in sources and have strong regeneration capabilities. However, papermaking and low-end weaving are still the main ways of utilization, and even incineration is still used to pollute the environment. The means of processing these products has brought serious environmental pollution and waste of cellulose raw materials. Therefore, the rational use of products will be the development direction of this kind of fiber raw materials.

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