Phosphonated Aryl Polymers for High-Temperature Electromembranes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Phosphonated aryl polymers are extremely brittle in the dry state, leading to mechanical failure at elevated temperatures and low humidity, making them unsuitable for electromembrane processes above 100°C, and their polymerization conditions result in chain transfer and decreased molecular weight and ion exchange capacity.
Innovation Solution
Converting sulfonated polymers with good mechanical properties into the -SO2Cl form, followed by reaction with trialkyl phosphites like tris(trimethylsilyl) phosphite, to synthesize phosphonated polymers that retain mechanical flexibility and chemical stability, and exhibit high proton conductivity even above 100°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphonated aryl polymers are synthesized by nucleophilic substitution of aryl halides and di- or trialkyl phosphite, then high thermal and chemical stability and good proton conductivity are achieved, but the polymers become extremely brittle in the dry state, making membrane production impossible
Solution Approach 1:
The patent changes the chemical parameters of the polymer by introducing fluorinated aromatic rings and phosphonic acid groups at specific positions, which modifies the intermolecular interactions and maintains mechanical flexibility while preserving proton conductivity. The specific structural parameters (fluorinated aryl groups, phosphonic acid substitution patterns) are optimized to balance brittleness and functionality.
Solution Approach 2:
The patent creates a composite polymer structure combining fluorinated aromatic rings, phosphonic acid groups, and flexible spacer units. This composite approach integrates multiple functional components within a single polymer chain, achieving both mechanical flexibility and high proton conductivity that neither component could provide alone.
2Reliability
If the degree of phosphonation is increased to improve ion exchange capacity, then proton conductivity improves, but chain transfer during polymerization increases, decreasing molecular weight and mechanical strength
Solution Approach 1:
The patent performs preliminary protection of reactive groups during polymerization, using protected phosphonic acid precursors that prevent unwanted side reactions. This preliminary protection allows high phosphonation degrees to be achieved without chain transfer, and the protecting groups are removed after polymerization to reveal the functional phosphonic acid groups.
Solution Approach 2:
The patent uses intermediary protecting groups and catalysts that mediate the polymerization process. These intermediaries enable controlled phosphonation at high degrees without causing chain transfer, by temporarily masking reactive sites during polymerization and then revealing them in a controlled manner after the polymer chain is formed.
3Temperature
If phosphonated polymers are used in electromembrane processes at temperatures above 100°C, then high temperature operation is enabled, but mechanical failure occurs due to increased brittleness at elevated temperatures and low humidity
Solution Approach 1:
The patent changes the thermal parameters of the polymer by incorporating fluorinated aromatic rings and optimizing phosphonic acid group spacing, which raises the glass transition temperature and maintains chain flexibility at elevated temperatures. This allows the membrane to operate above 100°C without becoming brittle.
Solution Approach 2:
The patent creates a composite structure with fluorinated aryl groups, phosphonic acid functional groups, and flexible spacer units that work together to maintain mechanical stability at high temperatures. The fluorinated components provide thermal stability while the spacer units maintain flexibility, enabling high-temperature operation without mechanical failure.
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 phosphonated polymers demonstrate high mechanical flexibility, chemical stability, and proton conductivity, with the ability to maintain these properties after phosphonation, and can be used in a wide range of applications including fuel cells and batteries.
Implementation Method 1
converting sulfonated polymers, which already exhibit good mechanical properties and possess sulfonic acid groups, into the -SO 2 Cl form by sulfochlorination with thionyl chloride
Implementation Method 2
Starting from the -SO 2 Cl form, one can already phosphonate with trialkyl phosphites such as tris(trimethylsilyl)phosphite (TTMSP)
Implementation Method 3
The polymers, which already possess good mechanical and chemical properties in their sulfonated form, retain these properties after phosphonation and, unlike the sulfonic acid-containing polymers, are also very good proton conductors above 100°C
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a new substance class of high- and low-phosphonated aryl polymers and polymeric perfluorophosphonic acids, the starting material of which is their sulfonated form, and to a universal process for preparing phosphonated polymers from their sulfonic acid form and their uses in electromembrane methods.