Cation Exchange Membrane Composition for Low Brittleness and Resistance
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Solution Overview
Problem
Existing cation exchange membranes (CEMs) are unstable, prone to phase separation, leading to inhomogeneities that increase electrical resistance and decrease perm selectivity, and are often brittle, making them costly and less effective for applications such as fuel cells and electrolysis.
Innovation Solution
A cation exchange membrane composition comprising specific ratios of crosslinking agents with anionic and ethylenically unsaturated groups, polymerized by electron beam or actinic radiation, and optionally with a porous support, to enhance stability and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If standard curable compositions are used to prepare CEMs, then the membranes can be formed, but they become unstable and phase separate leading to inhomogeneities
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking agents, specifically using agents with at least 5 vinyl groups and freedom from ionic groups, which fundamentally alters the polymerization behavior and prevents phase separation while maintaining homogeneity
Solution Approach 2:
The patent creates a composite crosslinking system combining multiple crosslinking agents with specific characteristics (high vinyl content, no ionic groups) that work synergistically to produce a homogeneous membrane structure with improved stability
2Reliability
If conventional CEM compositions are used, then membrane formation is achieved, but electrical resistance increases due to inhomogeneities
Solution Approach 1:
The patent modifies the crosslinking agent parameters (vinyl group count ≥5, absence of ionic groups) to achieve a more uniform polymer network, which reduces electrical resistance by eliminating inhomogeneities that act as resistance barriers
3Reliability
If traditional CEM formulations are employed, then ion exchange function is provided, but perm selectivity decreases due to inhomogeneities
Solution Approach 1:
The patent changes the molecular parameters of the crosslinking agents to achieve uniform polymer distribution, which directly improves perm selectivity by ensuring consistent ion transport pathways throughout the membrane
4Strength
If standard CEM compositions are used, then membrane function is achieved, but mechanical strength decreases making membranes brittle
Solution Approach 1:
The patent changes the crosslinking density and network structure by using agents with at least 5 vinyl groups, creating a more flexible and durable polymer network that maintains mechanical strength while reducing brittleness
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 composition results in a stable, low-resistance, and high-permselectivity membrane with improved mechanical properties, suitable for various applications including fuel cells and electrolysis.
Implementation Method 1
polymerized by electron beam or actinic radiation
Implementation Method 2
polymerized by electron beam or actinic radiation
Data Source
AI summary
Compositions and cation exchange membranes having low brittleness, low ER, good pH stability and good PS 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; and (c) a third crosslinking agent comprising 2, 3 or 4 polymerisable groups and being free from ionic groups.