CN102877342A - Method for preparing cellulose nanocrystals - Google Patents

Abstract

The invention discloses a method for preparing cellulose nanocrystals. The method comprises the following steps of: (1) putting refined cotton linter into water of which the mass is 10 to 20 times that of the refined cotton linter, and performing ultrasonic stirring in an ultrasonic generator for 4 to 8 hours; (2) continuously adding a 0.5mol/L sulfuric acid aqueous solution of which the mass is 5 to 8 times that of the refined cotton linter and a 0.5mol/L hydrochloric acid aqueous solution of which the mass is 2 to 6 times that of the refined cotton linter into the ultrasonic generator, and performing ultrasonic stirring at the temperature of between 30 and 60 DEG C for 8 to 12 hours; and (3) washing a solid product obtained in the step (2) by using water until the pH value is 6 to 7. The method is simple in process and low in cost; and the prepared cellulose nanocrystals are uniform in granularity and high in performance.

Description

A kind of preparation method of nano micro crystal cellulose

Technical field

The present invention relates to the cellulose derivative technology field, especially relate to a kind of cellulosic method of nano-sized crystal for preparing.

Background technology

Microcrystalline cellulose is a kind of pure cellulose depolymerization product, and granule size is at 20 ~ 80 μ m.By the native cellulose preparation, it is the crystalline powder of odorless, tasteless.Product is useful as drug excipient and tablet disintegrant on medical industry; Can make important functional food ingredient---dietary cellulosic in food industry, be a kind of desirable food supplement; Utilize its thixotropy and the thickening property thickener and the emulsifying agent that can be used as water based paint at coatings industry; It integrates filler, thickening and emulsification on cosmetics, and oily matter is had good emulsifying capacity; In wet method manufacturer fabricate-leather is produced, use as tackify and filler, make artificial leather surface smoothing, even thickness.This shows, the purposes of microcrystalline cellulose is very extensive, and domestic demand to this product will constantly increase.

Nano micro crystal cellulose not only has basic structure and the performance of microcrystalline cellulose, also has the characteristic of nano particle, and such as huge specific area, superpower adsorption capacity and high reactivity, so its application prospect is very wide.The method that present degraded cellulose prepares microcrystalline cellulose mainly contains acid-hydrolysis method and enzyme hydrolysis method.Need high concentration strong acid in the acid-hydrolysis method, corrosivity is large, and cost is high; The degradation efficiency of enzyme hydrolysis is lower, is difficult to realize suitability for industrialized production.

Summary of the invention

For the problems referred to above that prior art exists, the applicant provides a kind of preparation method of nano micro crystal cellulose.This method technique is simple, and is with low cost, and preparation-obtained nano micro crystal cellulose epigranular is functional.

Technical scheme of the present invention is as follows:

A kind of preparation method of nano micro crystal cellulose, concrete steps are as follows:

(1) refined cotton linter is dropped into quality in its water of 10 ~ 20 times, placed the supersonic generator ultrasonic agitation 4 ~ 8 hours;

(2) continuing to add quality in supersonic generator is the aqueous sulfuric acid of the 0.5mol/L of 5 ~ 8 times of refined cotton linter quality, and quality is the aqueous hydrochloric acid solution of the 0.5mol/L of 2 ~ 6 times of refined cotton linter quality, keep to stir under 30 ~ 60 ℃ temperature ultrasonic 8 ~ 12 hours;

(3) step (2) gained solid product being washed with water to pH value 6 ~ 7 gets final product.

The technique effect that the present invention is useful is:

The present invention is ultrasonic agitation pretreatment of fiber element at first, water generates microbubble under ultrasonic effect, the moment of microbubbles rupture produces high energy, can effectively refined cotton linter be separated and crack, make cellulosic molecule be in the state that elongation is stretched, be convenient in follow-up acidolysis process, be degraded.Stirring can make the more even of refined cotton linter dispersion, does not produce caking.

Because cellulose has passed through preliminary treatment, so the acidolysis process reduces greatly to the concentration requirement of sulfuric acid and hydrochloric acid, ultrasonic wave is so that acid solution forms a large amount of high energy minute bubbles simultaneously, in chemical degradation, also increased the physical action of bombardment cellulose macromolecule, heating is so that the active increase of the group of cellulose macromolecule, therefore more easily be broken down into little molecule, can be easy to cellulose degradation be that particle is the nano-sized crystal cellulose of 5 ~ 10nm to method provided by the present invention.

The specific embodiment

Embodiment 1

(1) the 3g refined cotton linter being dropped into quality is in the water of 30g, places the supersonic generator ultrasonic agitation 8 hours;

(2) continuing to add quality in supersonic generator is the aqueous sulfuric acid of the 0.5mol/L of 15g, and quality is the aqueous hydrochloric acid solution of the 0.5mol/L of 18g, keeps stirring under 30 ℃ temperature ultrasonic 12 hours;

(3) step (2) gained solid product being washed with water to pH value 6 ~ 7 gets final product.

Embodiment 2

(1) the 3g refined cotton linter being dropped into quality is in the water of 45g, places the supersonic generator ultrasonic agitation 6 hours;

(2) continuing to add quality in supersonic generator is the aqueous sulfuric acid of the 0.5mol/L of 21g, and quality is the aqueous hydrochloric acid solution of the 0.5mol/L of 12g, keeps stirring under 50 ℃ temperature ultrasonic 10 hours;

(3) step (2) gained solid product being washed with water to pH value 6 ~ 7 gets final product.

Embodiment 3

(1) the 3g refined cotton linter being dropped into quality is in the water of 60g, places the supersonic generator ultrasonic agitation 4 hours;

(2) continuing to add quality in supersonic generator is the aqueous sulfuric acid of the 0.5mol/L of 24g, and quality is the aqueous hydrochloric acid solution of the 0.5mol/L of 6g, keeps stirring under 60 ℃ temperature ultrasonic 8 hours;

(3) step (2) gained solid product being washed with water to pH value 6 ~ 7 gets final product.

Claims (1)

1. the preparation method of a nano micro crystal cellulose is characterized in that concrete steps are as follows:

(1) refined cotton linter is dropped into quality in its water of 10 ~ 20 times, placed the supersonic generator ultrasonic agitation 4 ~ 8 hours;

(2) continuing to add quality in supersonic generator is the aqueous sulfuric acid of the 0.5mol/L of 5 ~ 8 times of refined cotton linter quality, and quality is the aqueous hydrochloric acid solution of the 0.5mol/L of 2 ~ 6 times of refined cotton linter quality, keep to stir under 30 ~ 60 ℃ temperature ultrasonic 8 ~ 12 hours;

(3) step (2) gained solid product being washed with water to pH value 6 ~ 7 gets final product.