Radiation-Crosslinked Ionic Polymer Membrane for High Ion Exchange
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Solution Overview
Problem
Commercial ionic polymer membranes face challenges with high production costs and low thermo-stability, and hydrocarbon-based membranes have issues with dimensional stability as ion exchange capacity increases, making it difficult to produce membranes with high ion exchange capacity and durability.
Innovation Solution
A flexible crosslinked ionic polymer membrane is developed by mixing commercial ionic polymers with specially synthesized double bond-introduced hydrophilic poly(vinyl alcohol) and irradiating the mixture to create a 3-dimensional network structure, allowing for high ion exchange capacity and durability while reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perfluorinated ionic polymer membrane is used, then ion exchange capacity is improved, but production cost increases and thermo-stability decreases
Solution Approach 1:
The patent replaces expensive perfluorinated polymers with cheaper hydrocarbon-based polymers as the base material, achieving cost reduction while maintaining functional performance through additive modification rather than using inherently expensive materials
Solution Approach 2:
The patent creates a composite system by combining hydrocarbon-based polymer with poly(vinyl alcohol) and crosslinking agents, achieving both low cost and high ion exchange capacity through material composition rather than relying on expensive base polymers
2Ease of manufacture
If hydrocarbon based ionic polymer membrane is used, then production cost is reduced, but dimensional stability deteriorates with increasing ion exchange capacity
Solution Approach 1:
The patent introduces crosslinkable functional groups (double bonds) into the poly(vinyl alcohol) before membrane formation, enabling subsequent crosslinking to pre-establish dimensional stability before the membrane is put into service, preventing the dimensional instability that would otherwise occur with high ion exchange capacity
Solution Approach 2:
The patent changes the chemical structure of poly(vinyl alcohol) by introducing double bonds at specific positions, transforming it from a non-crosslinkable to a crosslinkable polymer, thereby enabling dimensional stability while maintaining low production cost
3Strength
If thermal-crosslinking method is used, then crosslinked structure is formed, but processing time increases
Solution Approach 1:
The patent replaces thermal energy input with radiation energy (electron beam or gamma ray) to induce crosslinking, eliminating the need for prolonged thermal processing while achieving the same crosslinked structure formation, thereby dramatically reducing processing time
Solution Approach 2:
The patent utilizes radiation-induced phase transition in the crosslinking process, where radiation energy directly triggers chemical bond formation without requiring the thermal phase transitions and extended heating periods needed in conventional thermal-crosslinking methods
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 solution results in an ionic polymer membrane with excellent processability, high ion exchange capacity, and durability, enabling cost-effective mass production suitable for applications like capacitive deionization, electrodialysis, and seawater desalination, with a significant reduction in processing time compared to conventional thermal-crosslinking methods.
Implementation Method 1
the present inventors developed a flexible crosslinked ionic polymer membrane with a high ion exchange capacity and high dimensional stability that has been produced simply by mixing the commercial ionic polymer having 100 mol % of ion-exchangeable functional group with a specially synthesized double bond-introduced hydrophilic poly(vinyl alcohol) at a certain ratio, followed by irradiation
Data Source
AI summary
The present invention provides an ionic polymer membrane prepared by irradiating the compound represented by formula 1 and an ionic polymer. The ionic polymer membrane of the present invention has the advantage of excellent processability, low production costs, high ion exchange capacity and high durability. Also, the method for preparing the ionic polymer membrane of the invention not only facilitates the production of the ionic polymer membrane in a 3-dimensional network structure which has high ion exchange capacity and high dimensional stability but also makes it easy to produce membranes in various forms and sizes by using the composition itself as a coating solution with using the commercialized inexpensive ionic polymer without additional high-risk multi-step introduction process of ionic exchange group. In the aspect of preparation process, the simplicity of the process and suitable for the mass-production, and the production cost is reduced by saving the processing time as much as minimum 1/15 (56 min.) in comparison to the processing time of the conventional thermal-crosslinking (1 hour).