Phosphonated Fluoroelastomers for Dry High-Temperature Proton Conduction

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Solution Overview

Problem

Existing phosphonized aryl polymers are mechanically unstable and prone to breaking in a dry, non-hydrated state, especially at high temperatures, limiting their application in electromembrane systems.

Innovation Solution

Phosphonization of non-conductive fluor-elastomers (FKM and FFKM) using trialkylphosphites like tris(trimethylsilyl) phosphite, which maintains mechanical and chemical stability while enabling proton conductivity even above 100°C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phosphonated aryl polymers are used to achieve proton conductivity at high temperatures, then proton conductivity is improved, but mechanical stability deteriorates causing fracture in dry state

Engineering Contradiction:
Improveproton conductivityVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the base polymer material from aryl polymers to fluorinated elastomers (FKM/FFKM), which fundamentally alters the mechanical properties while maintaining chemical stability. This parameter change in the polymer backbone structure enables the material to retain flexibility and strength in dry state while incorporating phosphonic acid groups for proton conductivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure by combining fluorinated elastomer backbone with phosphonic acid functional groups. The fluorinated elastomer provides mechanical strength and chemical stability, while the phosphonic acid groups provide proton conductivity, achieving a synergistic effect that resolves the contradiction between mechanical stability and proton conductivity.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If phosphonated aryl polymers are used to achieve thermal stability, then chemical stability is improved, but mechanical stability deteriorates in non-hydrogenated state

Engineering Contradiction:
Improvechemical stabilityVSAvoidmechanical stability
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent changes the polymer backbone from aryl structure to fluorinated elastomer structure, which maintains high chemical and thermal stability inherent to fluorinated polymers while providing superior mechanical properties compared to phosphonated aryl polymers. The fluorinated backbone resists chemical degradation while maintaining flexibility across a wide temperature range.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies phosphonic acid functional groups locally to the fluorinated elastomer backbone at controlled phosphonation degrees (0.1-5000 wt.%). This localized functionalization provides necessary proton conductivity and chemical stability without compromising the overall mechanical integrity of the fluorinated elastomer matrix.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If phosphonated polymers are made soluble in organic solvents for membrane production, then ease of manufacture is improved, but mechanical stability may deteriorate

Engineering Contradiction:
Improvesolubility in organic solventsVSAvoidmechanical stability
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the base polymer to fluorinated elastomers which inherently possess good solubility in common organic solvents due to their fluorinated structure. This enables solution processing for membrane fabrication while the fluorinated backbone maintains mechanical strength and flexibility, resolving the contradiction between manufacturability and mechanical stability.

Inventive Principle:
Principle #35Parameter changes

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 resulting phosphonized fluor-elastomers exhibit enhanced mechanical and chemical stability, excellent proton conductivity at high temperatures, and solubility in organic solvents, making them suitable for electromembrane applications.

Implementation Method 1

The most frequently described phosphonated systems are based on aryl polymers synthesized by nucleophilic substitution (Michaelis-Arbusow and Michaelis-Becker rearrangement) of aryl halides and di- or trialkyl phosphite

Methodology Applied
Scientific EffectNucleophilic substitution: Chemical Bonding

Implementation Method 2

They also exhibit good proton conductivity, even in the non-humidified state at temperatures above 100°C

Methodology Applied
Scientific EffectProton conduction: Conduction (electrical)

Data Source

PatentEP4298137B1Novel phosphonated fluoroelastomers (PFKMS), phosphonated perfluoroelastomers (pffkms), their process of preparation and use in electromembrane applications
Publication Date: 2025.04.02 RIVA POWER SYST GMBH & CO KG
  • EP4298137B1 patent drawingFigure 1
  • EP4298137B1 patent drawingFigure 2
  • EP4298137B1 patent drawingFigure 3

AI summary

The invention relates to a novel class of substances of highly and low phosphonated aliphatic fluoropolymer rubbers (pFKM) and perfluoropolymer rubbers (pFFKM) on the basis of FKM and FFKM and to their process of preparation and uses.