Fine Cellulose Fiber Production via Ionic Liquid Fibrillation
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Solution Overview
Problem
Current methods for producing fine cellulose fibers face challenges such as fiber damage, low crystallinity, and high energy consumption due to the need for strong mechanical fibrillation and dehydration steps, as well as issues with cost and permeability of solvents in existing chemical methods.
Innovation Solution
A method involving impregnation of cellulose with a fibrillation solution containing a carboxylic acid vinyl ester or aldehyde and an aprotic solvent with a donor number of 26 or more, which cleaves hydrogen bonds without mechanical crushing, allowing for fibrillation and surface modification without damaging the crystal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strong mechanical fibrillation is used to separate microfibrils, then the hydrogen bonds between cellulose fibers are cleaved and fibrillation is achieved, but the cellulose nanofibers are damaged and fiber shape damage occurs
Solution Approach 1:
The patent replaces strong mechanical fibrillation with chemical fibrillation using an ionic liquid. The ionic liquid penetrates the cellulose structure and cleaves hydrogen bonds through chemical interaction, achieving microfibril separation without the need for intense physical force that would damage the fibers.
Solution Approach 2:
The patent changes the physical-chemical parameters of the cellulose by using ionic liquid as a solvent. The ionic liquid alters the hydrogen bonding network and swelling behavior of cellulose, enabling fibrillation through chemical means rather than mechanical force, thus preserving fiber integrity while achieving separation.
2Ease of manufacture
If dehydration treatment is performed after fibrillation to composite cellulose microfibrils with resin, then the cellulose and resin can be combined, but high energy consumption is required
Solution Approach 1:
The ionic liquid acts as an intermediary medium that enables direct compositing of cellulose microfibrils with resin without requiring dehydration. The ionic liquid maintains a suitable environment for both cellulose and resin, allowing them to be combined directly while the ionic liquid can be recovered and reused.
Solution Approach 2:
Instead of discarding the ionic liquid through energy-intensive dehydration, the patent recovers and reuses the ionic liquid after the compositing process. This recovery approach significantly reduces energy consumption while maintaining the compositing capability of the system.
3Manufacturing precision
If mixed solvent containing ionic liquid and organic solvent is used for swelling and esterification, then fine cellulose fibers with esterified surfaces can be produced, but the cost of recovery and reuse of ionic liquid is high
Solution Approach 1:
The patent extracts and removes the organic solvent from the mixed solvent system, using only the ionic liquid for the esterification process. This simplification reduces the complexity of solvent recovery and reuse, thereby lowering the cost while still achieving surface modification of the cellulose fibers.
Solution Approach 2:
The patent employs a simplified solvent system where the ionic liquid can be easily recovered and reused multiple times. By eliminating the need to handle and recover mixed solvents, the effective cost per use of the ionic liquid is reduced, making the surface modification process more economically viable.
4Manufacturing precision
If organic solvent and esterifying agent are used together with mechanical pulverization for esterification, then the surface of cellulose can be esterified and dissociated, but the solution has low permeability and chemical fibrillation is not performed
Solution Approach 1:
The patent replaces mechanical pulverization with chemical fibrillation using ionic liquid. The ionic liquid penetrates deeply into the cellulose structure through chemical interaction, enabling both esterification and microfibril separation simultaneously without relying on mechanical force.
Solution Approach 2:
The patent changes the permeability parameter by using ionic liquid instead of organic solvent. The ionic liquid has superior penetration capability into the cellulose matrix due to its unique ionic structure and ability to disrupt hydrogen bonding, allowing efficient impregnation and chemical modification throughout the fiber structure.
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
This approach results in fine cellulose fibers with high crystallinity and reduced fiber shape damage, achieving efficient fibrillation and surface modification while reducing energy consumption and improving redispersibility and interfacial adhesive properties.
Implementation Method 1
a fibrillation solution containing a carboxylic acid vinyl ester or an aldehyde and an aprotic solvent having a donor number of 26 or more and impregnating the cellulose with the fibrillation solution to fibrillate the cellulose
Implementation Method 2
a fibrillation solution containing a carboxylic acid vinyl ester or an aldehyde and impregnating the cellulose with the fibrillation solution to fibrillate the cellulose
Data Source
AI summary
Provided is a method of producing fine cellulose fibers that are nanosized, that have a high crystallinity degree, and that are less vulnerable to fiber shape damage, the method including impregnating cellulose with a fibrillation solution to fibrillate the cellulose without mechanical crushing, and modifying the cellulose. The method of producing cellulose microfibrils of the present invention includes impregnating cellulose with a fibrillation solution containing a carboxylic acid vinyl ester or an aldehyde and an aprotic solvent having a donor number of 26 or more to fibrillate the cellulose. The aldehyde is at least one kind of aldehyde selected from the group consisting of an aldehyde represented by the following formula (1), paraformaldehyde, cinnamaldehyde, perillaldehyde, vanillin, and glyoxal:R1—CHO (1)where R1 represents a hydrogen atom, an alkyl group having 1 to 16 carbon atoms, an alkenyl group, a cycloalkyl group, or an aryl group.