Bipolar Membrane Cation Exchange Layer Crosslinking
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Solution Overview
Problem
Existing bipolar membranes (BPMs) face challenges in achieving good permselectivity and producing high-purity acids and bases.
Innovation Solution
A bipolar membrane comprising an anion exchange layer (AEL) and a cation exchange layer (CEL) is developed, where the CEL is obtained by curing a curable composition containing specific crosslinking agents, including a first crosslinking agent with an anionic group and polymerisable groups, a second crosslinking agent with multiple vinyl groups and no ionic groups, and a third crosslinking agent with fewer polymerisable groups and no ionic groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bipolar membranes are used, then the structure is simple, but the permselectivity is insufficient and high-purity acid and base production is not achieved
Solution Approach 1:
The patent applies composite materials by combining three different crosslinking agents in the cation exchange layer: (a1) a first crosslinking agent with anionic groups and polymerisable groups, (b1) a second crosslinking agent with multiple vinyl groups and no ionic groups, and (c1) a third crosslinking agent with fewer polymerisable groups and no ionic groups. This composite approach creates a complex crosslinked network structure that enhances permselectivity while maintaining membrane integrity, directly resolving the contradiction between simple structure and high performance.
2Manufacturing precision
If conventional bipolar membranes are used, then the manufacturing process is simple, but high-purity acid and base production is not achieved
Solution Approach 1:
The patent employs preliminary action by using a curable composition that is prepared in advance with specific crosslinking agents (a1), (b1), and (c1) already incorporated. The composition is designed to be cured into the final membrane structure through a subsequent curing process, allowing the complex crosslinked network to be formed during manufacturing rather than requiring complex multi-step synthesis. This enables high-purity acid and base production while maintaining ease of manufacture.
3Productivity
If conventional bipolar membranes are used, then the production efficiency is low, but high-purity products are not achieved
Solution Approach 1:
The patent applies parameter changes by optimizing the composition and ratios of the three crosslinking agents in the cation exchange layer. Specifically, it defines precise compositional parameters: (a1) first crosslinking agent with anionic groups and polymerisable groups, (b1) second crosslinking agent with at least 5 vinyl groups, and (c1) third crosslinking agent with 2, 3 or 4 polymerisable groups. These parameter optimizations create a crosslinked network that enhances both production efficiency and product purity simultaneously, resolving the contradiction between productivity and reliability.
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 developed bipolar membrane exhibits improved permselectivity and is capable of producing high-purity acids and bases, enhancing its performance and efficiency in applications such as bipolar electrodialysis devices.
Implementation Method 1
a curable composition comprising: (a1) a first crosslinking agent comprising an anionic group and at least two polymerisable groups; (b1) a second crosslinking agent comprising at least 5 vinyl groups and being free from ionic groups; (c1) a third crosslinking agent comprising 2, 3 or 4 polymerisable groups and being free from ionic groups
Implementation Method 2
the cation exchange layer is obtainable by curing a curable composition comprising... a first crosslinking agent... a second crosslinking agent... a third crosslinking agent
Implementation Method 3
Bipolar membranes (BPMs) have both a cationic layer (sometimes called an anion exchange layer or 'AEL') and an anionic layer (sometimes called a cation exchange layer or 'CEL')
Data Source
AI summary
A bipolar membrane comprising an anion exchange layer and a cation exchange layer, wherein the cation exchange layer is obtainable by curing a composition comprising: (a) a first crosslinking agent comprising an anionic group and at least two polymerisable groups; (b) a second crosslinking agent comprising at least 5 vinyl groups and being free from ionic groups; (c) a third crosslinking agent comprising 2, 3 or 4 polymerisable groups and being free from ionic groups.