Sulfonated PEEK Fiber Screen for Cost-Effective Cation Exchange

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Solution Overview

Problem

Current cation exchange membranes, such as those made from PEEK, are inefficient for water transport due to their hydrophobic nature, and alternatives like Nafion are costly and environmentally unfriendly.

Innovation Solution

A sulfonated PEEK (SPEEK) screen is fabricated by sulfonating PEEK fibers in a sulfuric acid bath, creating hydrophilic regions that enhance water interaction and ion transport, offering a cost-effective and environmentally friendly alternative to Nafion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PEEK fibers are used to make cation exchange membranes, then the membranes have good mechanical properties and chemical stability, but they are hydrophobic and inefficient for water transport

Engineering Contradiction:
Improvemechanical properties and chemical stabilityVSAvoidhydrophobicity causing inefficient water transport
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by sulfonating the PEEK polymer fibers, which chemically modifies the material properties. The sulfonation reaction introduces sulfonic acid groups (-SO3H) onto the PEEK backbone, transforming the hydrophobic PEEK into hydrophilic SPEEK. This chemical parameter change enables the membrane to efficiently transport water and ions while preserving the underlying PEEK structure's mechanical and chemical stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material structure where sulfonic acid groups are integrated into the PEEK fiber matrix. The resulting SPEEK membrane combines the robust mechanical and chemical properties of PEEK with the hydrophilic and ion-conductive characteristics of sulfonic acid groups, achieving both structural integrity and efficient water/ion transport.

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If Nafion is used as an alternative to PEEK for cation exchange membranes, then water transport efficiency is improved, but cost increases and environmental friendliness decreases

Engineering Contradiction:
Improvewater transport efficiencyVSAvoidcost and environmental impact
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent employs a cost-effective approach by using readily available PEEK fibers and performing sulfonation in situ using common sulfuric acid. This eliminates the need for expensive Nafion material while achieving comparable or superior performance. The process uses inexpensive, environmentally friendly reagents and avoids the costly manufacturing and disposal issues associated with Nafion.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent transforms ordinary PEEK into high-performance SPEEK through chemical sulfonation, creating a material with water transport efficiency comparable to Nafion but at a fraction of the cost. The parameter change approach allows optimization of hydrophilicity and ion exchange capacity without requiring expensive proprietary materials.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If sulfonation reaction is performed on PEEK fibers, then hydrophilicity and ion exchange capacity are improved, but excessive sulfonation may degrade the polymer structure

Engineering Contradiction:
Improvehydrophilicity and ion exchange capacityVSAvoidpolymer structure integrity
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent applies partial action by controlling the sulfonation process to achieve optimal rather than complete sulfonation. By limiting the reaction time, temperature, and sulfuric acid concentration, the process achieves sufficient hydrophilicity and ion exchange capacity while preventing excessive sulfonation that would degrade the PEEK backbone structure. This controlled partial modification optimizes the balance between performance and structural stability.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent incorporates feedback control in the sulfonation process by monitoring reaction conditions and adjusting parameters to maintain polymer structure integrity. The process is designed to stop at the optimal point where desired hydrophilicity is achieved without compromising the mechanical and chemical stability of the PEEK framework.

Inventive Principle:
Principle #23Feedback

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 SPEEK screen enables efficient water penetration and ion transport, reducing the contact angle of water droplets and improving the ion exchange capacity, making it suitable for electro-catalytic conversion of CO2 into value-added chemicals and synthetic fuels.

Implementation Method 1

contacting a plurality of unsulfonated polymer fibers with an acid comprising a sulfur containing group to sulfonate the plurality of unsulfonated polymer fibers in a sulfonation reaction

Methodology Applied
Scientific EffectSulfonation:

Implementation Method 2

The SPEEK screen enables efficient water penetration and ion transport, reducing the contact angle of water droplets and improving the ion exchange capacity

Methodology Applied
Scientific EffectIon Exchange: Ion Exchange

Data Source

PatentEP4223922A1Polymer fiber screen surface modifications for cation exchange membranes
Publication Date: 2023.08.09 XEROX CORP
  • EP4223922A1 patent drawingFigure 1
  • EP4223922A1 patent drawingFigure 2
  • EP4223922A1 patent drawingFigure 3

AI summary

A sulfonated polymer fiber screen and a method for fabricating the same is disclosed. For example, a composition may include a plurality of sulfonated polymer fibers. The sulfonated polymer fibers may include polyether ether ketone (PEEK) fibers or polyaryl ether ketone (PAEK) fibers that are contacted with an acid bath that includes a sulfur containing group.