Method for dissolving natural cellulose

A natural cellulose and solution technology, applied in the field of natural polymers, can solve the problems of low reactivity of cellulose, long dissolution time, complex conditions, etc., and achieve the effects of good stability, strong operability and high safety

Inactive Publication Date: 2014-05-14
SHANGHAI UNIV OF ENG SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The dissolution of natural cellulose is difficult because of its high degree of polymerization, and there are relatively few related documents and patents. In 2010, Chinese patent CN102061001A mentioned that the method of dissolving cellulose in LiCl / DMAC requires vacuum distillation in a vacuum kettle , complex conditions, long dissolution time, and can only degrade cellulose with a degree of polymerization not exceeding 900, and cellulose with a degree of polymerization higher than 900 cannot be dissolved
[0004] Due to the existence of a large number of hydrogen bonds in and between molecules of natural cellulose, and the complexity and high crystallinity of cellulose morphological structure and aggregated structure, a large number of reactive hydroxyl groups are blocked, making it difficult to dissolve and low reactivity of cellulose. , poor uniformity

Method used

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  • Method for dissolving natural cellulose

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Embodiment 1

[0029] (1) Cut 5g of natural cotton fibers into pieces, put them into 200mL of NaOH solution with a mass concentration of 17%, activate them with ultrasonic wave at room temperature for 60min, wash the cotton fibers with deionized water until neutral; Cotton fibers were first immersed in 50mL of dimethylacetamide (DMAC) for 45 minutes; then immersed in 50mL of anhydrous methanol for 45 minutes, and finally dried in an electric blast drying oven;

[0030] (2) Dry LiCl in a vacuum oven at 150°C for 18 hours. Under the protection of nitrogen, take dry 10g LiCl and add it to 100mL of DMAC, stir and dissolve, heat up to 100°C, add to step (1) and dry Keep the temperature of 100°C, stir for 120min, and the stirring speed is 500rpm / min; drop to room temperature and continue stirring, the stirring speed is still 500rpm / min, stirring and dissolving for 4 hours, ultrasonic vibration and defoaming of the solution for 60min, to obtain Uniform and transparent spinning solution, the mass fr...

Embodiment 2

[0033] (1) Cut 3 g of natural cotton fibers into pieces, put them into 200 mL of NaOH solution with a mass concentration of 17%, activate them with ultrasonic waves at room temperature for 50 minutes, and wash the cotton fibers to neutral with deionized water; Cotton fibers were first immersed in 50mL of dimethylacetamide (DMAC) for 40 minutes; then immersed in 50mL of anhydrous methanol for 40 minutes, and finally dried in an electric blast drying oven;

[0034] (2) Dry LiCl in a vacuum oven at 150°C for 18 hours. Under the protection of nitrogen, take dry 10g LiCl and add it to 100mL of DMAC, stir and dissolve, raise the temperature to 100°C, add to step (1) and dry Keep the temperature of 100°C, stir for 120min, and the stirring speed is 450rpm / min; drop to room temperature and continue stirring, the stirring speed is still 450rpm / min, stirring and dissolving for 4 hours, ultrasonic vibration and defoaming of the solution for 60min, to obtain Uniform and transparent spinnin...

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Abstract

The invention belongs to natural macromolecules and particularly relates to a method for dissolving natural cellulose. The method comprises the steps of cutting the natural cellulose into pieces, adding the natural cellulose into a NaOH solution, performing ultrasonic activation for 40-90 minutes, cleaning the natural cellulose with deionized water until the natural cellulose is neutral, respectively immersing the natural cellulose into a dimethylacetamide solution and an anhydrous alcohol solution for 30-60 minutes, and drying; under the protection of nitrogen, dissolving LiCl into dimethylacetamide, heating to 90-110 DEG C, adding the dried natural cellulose at 90-110 DEG C and stirring for 100-140min till the dried natural cellulose is dissolved; cooling to 20-25 DEG C, stirring for 3-5 hours, and performing ultrasonic oscillation. The method for dissolving the natural cellulose, which is provided by the invention, is used for performing activation pretreatment on the natural cellulose, so that the crystallinity of the cellulose is reduced, and the dissolving time of the cellulose is shortened; furthermore, the solution is uniform and stable. The method is friendly to the environment, pollution-free, high in operability, low in production cost and high in safety.

Description

technical field [0001] The invention relates to the field of natural polymers, in particular to a method for dissolving natural cellulose. Background technique [0002] Natural cellulose fiber is a renewable resource. Plants such as trees, cotton, rice stalks, and corn in nature and the secretions of some bacteria contain a large amount of natural cellulose. According to statistics, the world uses natural biosynthesis to produce hundreds of billions of tons of cellulose every year, which cannot be compared with petroleum resources. [0003] The solvent system of cellulose generally includes two types: one is the traditional dissolution method of cellulose, viscose method or cuproammonia method, which chemically reacts with cellulose to form derivatives to achieve the purpose of dissolution, mainly using acetone, carbon disulfide, etc. Solvents and additives, and the required cellulose needs to be yellowed, aged and matured. The dissolution process involves volatile reagents...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/09C08L1/02D01D1/02D01F2/02
Inventor 曹延娟辛斌杰吴湘济杜卫平张杰方珩刘岩潘劲
Owner SHANGHAI UNIV OF ENG SCI
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