Chitosan Fiber Spinning Solution Dissolving Process
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Solution Overview
Problem
Current chitosan fiber production processes result in low dry breaking strength, poor spinnability, and fluctuating product quality due to the use of medium deacetylation degree chitosan powder, which destroys the molecular chain structure and slows down the dissolving process, making it unsuitable for industrial continuous production.
Innovation Solution
A spinning solution using flake chitosan with a deacetylation degree ≥92% and viscosity ≥1000 mpa·s, where the flake chitosan is screened, vacuum-sealed, and dissolved with acetic acid under controlled conditions to maintain the molecular structure and enhance dissolving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flake chitosan is ground into powder to form spinning solution, then the dissolving process becomes easier, but the molecular chain structure is destroyed and viscosity decreases
Solution Approach 1:
The flake chitosan undergoes preliminary treatment including decalcification and deproteinization to create spaces between tissues that can be filled with acetic acid solution, facilitating subsequent dissolving without mechanical grinding that would destroy the molecular structure
Solution Approach 2:
Acetic acid solution acts as an intermediary that penetrates into the spaces of flake chitosan structure, enabling dissolving without direct mechanical contact that would break the molecular chains, thus maintaining viscosity while achieving dissolution
2Strength
If flake chitosan is used as raw material, then the molecular chain structure is preserved, but the dissolving rate is too slow for industrial production
Solution Approach 1:
The flake chitosan is pre-treated with decalcification and deproteinization to create a more open structure with spaces between tissues, which accelerates the subsequent dissolving rate without requiring mechanical grinding that would damage the molecular structure
Solution Approach 2:
The process utilizes liquid penetration where acetic acid solution infiltrates the flake chitosan structure through capillary action and pressure differential, enabling rapid dissolving while preserving the molecular chain integrity
3Ease of manufacture
If medium deacetylation degree chitosan is used, then the raw material is easier to obtain, but the dry breaking strength and spinnability of fiber are reduced
Solution Approach 1:
The process changes the deacetylation degree parameter from medium (75-85%) to high (≥92%), which fundamentally improves the fiber's dry breaking strength, spinnability, and functionality. This parameter change is achieved through optimized chemical treatment conditions during chitosan production
4Strength
If flake chitosan is vacuum-sealed and dissolved with acetic acid under controlled conditions, then the molecular structure is maintained and dissolving efficiency is enhanced, but the process complexity increases
Solution Approach 1:
The vacuum-sealed environment creates an inert atmosphere that prevents oxidation and degradation of chitosan during dissolving, preserving the molecular structure. The vacuum condition also removes air from the flake structure, enabling faster and more complete penetration of acetic acid solution
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method maintains the original molecular chain structure of chitosan, increases dry breaking strength and spinnability, and improves the uniformity and speed of the spinning solution preparation, meeting the requirements for high-performance industrial production.
Implementation Method 1
adding 0.9%-6% acetic acid solution, and soaking at the room temperature for 40-60 minutes; uniformly stirring at a rate of 26-60 rpm for 7.5-19 hours under a pressure of ≤5000 pa in the dissolving kettle
Implementation Method 2
putting in a dissolving kettle the screened flake chitosan raw material with a weight which is 3%-8% of the total weight of the spinning solution, sealing the dissolving kettle, and evacuating into vacuum
Data Source
AI summary
It is an object of the present invention to provide a spinning solution for industrial production of pure chitosan fiber and the method for fabricating the same. The method comprises the steps of: step (a): screening a flake chitosan raw material and removing impurities; step (b): putting in a dissolving kettle the screened flake chitosan raw material with a weight which is 3%-8% of the total weight of the spinning solution, sealing the dissolving kettle, and evacuating into vacuum; step (c): adding 0.9%-6% acetic acid solution, and soaking at the room temperature for 40-60 minutes; step (d): uniformly stirring at a rate of 26-60 rpm for 7.5-19 hours under a pressure of ≦5000 pa in the dissolving kettle, standing for 1-3 hours, and obtaining a spinning solution. By using this method, it is possible to not only maintain the original state structure of the molecular chain of chitosan, but also fast and uniformly dissolve flake chitosan and the spinning solution fabricated by this method in unit time, so as to meet the requirements in the industrial continuous production.