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Method for dissolving chitosan through combined use of acid and alkali

A technology of chitosan and combined use, applied in the field of acid-alkali combined use to dissolve chitosan, can solve the problems of affecting the mechanical properties of products, increasing molecular weight polydispersity, reducing molecular weight, etc., to avoid acid-catalyzed hydrolysis, avoid The effect of degrading and improving the preparation efficiency

Inactive Publication Date: 2013-12-25
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The intramolecular glycosidic bond of chitosan is also a hemiacetal structure. Therefore, when the acidic solution of chitosan is placed, an acid-catalyzed hydrolysis reaction will occur, and the main chain of the molecule will be continuously broken due to hydrolysis, resulting in a decrease in molecular weight and molecular weight. The polydispersity increases, which seriously affects the mechanical properties and other qualities of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] 1) Mix 8.0g lithium hydroxide, 2.0g potassium hydroxide, 6.0g urea and 84g water to obtain alkaline aqueous solution;

[0015] 2) The molecular weight of 3g is 2.5×10 6 Add 100 mL of acetic acid solution with a mass concentration of 1.0% to the chitosan raw material, stir and disperse for 20 seconds to obtain a chitosan-containing solution;

[0016] 3) Stir and mix the solution obtained in step 1) and the solution obtained in step 2) at a volume ratio of 1:1, freeze at -60°C for 1 hour, thaw at room temperature with stirring to obtain a chitosan solution.

Embodiment 2

[0018] 1) Mix 12.0g lithium hydroxide, 2.0g potassium hydroxide, 9.0g urea and 77g water to obtain alkaline aqueous solution;

[0019] 2) The molecular weight of 3g is 3.0×10 6 Add 100 mL of 0.5% hydrochloric acid solution to the chitosan raw material, stir and disperse for 60 seconds to obtain a chitosan-containing solution;

[0020] 3) The solution obtained in step 1) and the solution obtained in step 2) were stirred and mixed evenly at a volume ratio of 1:1, frozen at -40°C for 4 hours, thawed at room temperature and supplemented by stirring to obtain a chitosan solution.

Embodiment 3

[0022] 1) Mix 8.0g lithium hydroxide, 8.0g potassium hydroxide, 9.0g urea and 75g water to obtain alkaline aqueous solution;

[0023] 2) The molecular weight of 2g is 2.5×10 6 Add 100 mL of 4.0% hydrochloric acid solution to the chitosan raw material, stir and disperse for 30 seconds to obtain a chitosan-containing solution;

[0024] 3) Stir and mix the solution obtained in step 1) and the solution obtained in step 2) at a volume ratio of 1:1, freeze at -20°C for 3 hours, thaw at room temperature with stirring to obtain a chitosan solution.

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PUM

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Abstract

The invention discloses a method for dissolving chitosan through combined use of acid and alkali. The method comprises the steps of mixing lithium hydroxide, potassium hydroxide, urea and water according to mass percentage, so as to obtain an alkaline aqueous solution; adding a chitosan raw material into an acetic solution or hydrochloric solution, and carrying out stirring dispersion for 20-60 seconds, so as to obtain a chitosan-containing solution; uniformly stirring and mixing the alkaline aqueous solution and the chitosan-containing solution according to the volume ratio of 1: 1, freezing and unfreezing, thereby obtaining a chitosan solution. According to the method, acidic-alkaline solvent systems are used in a combined manner, so that an alkaline system solution of chitosan is obtained, and the degradation of chitosan in an acidic solution is avoided; moreover, the processes of swelling and solvent system pre-cooling are not required, so that the dissolving time is shortened, and the dissolving efficiency is increased.

Description

technical field [0001] The invention relates to a method for dissolving chitosan, in particular to a method for dissolving chitosan by combining acid and alkali. Background technique [0002] As the only natural alkaline polysaccharide, chitosan has a wide range of sources and abundant yield in nature. Chitosan has excellent biocompatibility and good biodegradability, and at the same time, its biological safety and low toxicity are very attractive. In addition, chitosan also has various biological activities, such as antibacterial properties and low immunogenicity. It has applications in medicine, environmental treatment, food industry, textile industry, etc., such as hemostatic and wound protection materials, heavy metal recovery, food additives, antibacterial fabrics, etc. [0003] The stability of chitosan solution has special and great significance for the application of chitosan. Chitosan can be dissolved in various inorganic acids and some organic acids, such as dil...

Claims

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Application Information

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IPC IPC(8): C08J3/03C08L5/08
Inventor 胡巧玲聂景怡王征科
Owner ZHEJIANG UNIV
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