High-DP Cellulose Fiber Solubilization With Zinc–Formic Acid
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Solution Overview
Problem
Existing methods for processing cellulose and protein fibers face limitations such as instability, hydrolysis, and inability to dissolve cellulose with high degrees of polymerization, leading to weak and brittle reconstituted materials.
Innovation Solution
A process involving solubilization of cellulose and protein sources using a solvent comprising zinc ions and formic acid, followed by extrusion into a coagulation bath, treatment with an oxidizing solution, and freezing to stabilize the materials for textile applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cellulose with high degree of polymerisation (DP > 1200) is processed using conventional wet spinning or solvent spinning systems, then the cellulose cannot be dissolved, but the invention uses zinc ions and formic acid to achieve solubility
Solution Approach 1:
The invention changes the chemical parameters of the solvent system by using zinc ions combined with formic acid instead of conventional solvents. This parameter change enables the dissolution of high DP cellulose (DP > 1200) that cannot be dissolved in traditional wet spinning or solvent spinning systems, while maintaining the integrity of the cellulose polymer chains.
2Reliability
If zinc salts and formic acid are used to dissolve cellulose, then the cellulose becomes soluble, but the material becomes susceptible to hydrolysis and degradation
Solution Approach 1:
The invention performs preliminary oxidation of the cellulose while it is in the dissolved state, before the cellulose can undergo hydrolysis or degradation. This preliminary action of oxidation stabilizes the cellulose structure and prevents subsequent hydrolytic degradation that would otherwise occur in the acidic zinc salt/formic acid environment.
Solution Approach 2:
The invention converts the potentially harmful effect of the acidic environment (which causes hydrolysis) into a beneficial process by using controlled oxidation. The oxidation process, initially seeming to be a degradation mechanism, actually stabilizes the cellulose by creating a more resistant structure that prevents further hydrolytic damage.
3Ease of manufacture
If conventional derivatisation to cellulose acetate is used, then the material becomes extrudable, but the invention seeks to avoid derivatisation while achieving similar results
Solution Approach 1:
The invention extracts or removes the need for conventional derivatisation processes (such as cellulose acetate formation) by using a novel solvent system based on zinc ions and formic acid. This extraction of the derivatisation step simplifies the manufacturing process while still achieving the desired extrudability of high DP cellulose.
4Stability of the object's composition
If natural fibres are used, then sustainability and moisture interaction are improved, but fibre diameter and staple length are limited by natural formation
Solution Approach 1:
The invention segments the natural cellulose into a dissolved state, allowing it to be reconstituted with controlled properties. By breaking down the natural fibre structure into molecular-level dissolution and then reassembling it through extrusion, the process maintains the sustainable and moisture-interacting properties of natural cellulose while gaining precise control over fibre diameter and other morphological parameters.
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
Produces stable cellulose and cellulose/protein fibers suitable for textile processing, overcoming the limitations of previous methods by achieving high solubility and stability, allowing for consistent fiber diameter and improved tensile properties.
Implementation Method 1
contacting a cellulose source with a solvent comprising zinc ions and formic acid to provide a solution
Implementation Method 2
extruding the solution from (a) into a coagulation bath to provide a solid material
Implementation Method 3
immersing the solid material from (b) in an oxidising solution
Implementation Method 4
freezing the oxidising solution in which the solid material is immersed
Data Source
AI summary
Disclosed is a process for solubilising cellulose and coagulating the resulting solution to form a cellulose-containing material. The process comprises contacting a cellulose source with a solvent comprising zinc ions and formic acid to provide a solution, coagulating the solution to provide a solid material, treating the solid material, and isolating the solid material after treatment, to provide the cellulose-containing material. The process can further comprise solubilising protein and coagulating the resulting solution to form a cellulose/protein-containing material. The cellulose-containing materials and cellulose/protein-containing materials can be produced, for example, as reconstituted fibres and films.