Fluorinated Copolymer Coated Membrane for Hot Sulfuric Acid
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Solution Overview
Problem
Porous fluoropolymer membranes, such as PTFE, lack resistance to extremely corrosive or oxidative fluids like hot sulfuric acid, limiting their suitability for applications in microelectronics and other industries.
Innovation Solution
A porous membrane comprising a fluorinated polymeric support coated with a copolymer consisting of halogenated vinyl monomers, perfluoro(alkyl vinyl)ether compounds with sulfonic acid groups or their salts, sulfonyl fluoride groups, and optionally vinylidene fluoride, which provides long-term stability in hot concentrated sulfuric acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If porous fluoropolymer membranes (PTFE) are used, then mechanical strength, chemical resistance, and thermal stability are improved, but resistance to extremely corrosive fluids (hot sulfuric acid) deteriorates
Solution Approach 1:
The patent applies composite materials by combining PTFE base membrane with a fluorinated copolymer coating layer. The copolymer contains perfluoro(alkyl vinyl)ether compounds with sulfonic acid groups or salts, creating a multi-layer composite structure where each layer contributes specific properties: PTFE provides mechanical strength and baseline chemical resistance, while the copolymer coating provides enhanced resistance to hot sulfuric acid and oxidative fluids
Solution Approach 2:
The patent changes chemical parameters by introducing sulfonic acid groups or salts into the copolymer structure. This chemical modification allows the membrane surface to interact with and resist hot sulfuric acid through ionic interactions and proton exchange mechanisms, fundamentally changing how the membrane responds to corrosive environments
2Adaptability or versatility
If surface coating is applied to modify PTFE, then suitability for specific applications is improved, but long-term stability in hot concentrated sulfuric acid deteriorates
Solution Approach 1:
The patent applies local quality by creating a specialized copolymer coating layer with specific chemical composition (perfluoro(alkyl vinyl)ether compounds with sulfonic acid groups) on the PTFE surface. This localized modification provides targeted chemical resistance properties in the coating layer while maintaining the bulk PTFE's mechanical properties, enabling the membrane to withstand hot sulfuric acid exposure over long periods
3Reliability
If plasma treatment or high energy surface modification is used, then surface chemical properties are improved, but resistance to oxidative fluids deteriorates
Solution Approach 1:
The patent changes chemical parameters by incorporating sulfonic acid groups or salts into the copolymer structure through controlled chemical synthesis. This creates a chemically stable surface layer that resists oxidative degradation, unlike plasma-treated surfaces that create reactive radical sites vulnerable to oxidative attack
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 coated membranes exhibit enhanced stability and resistance to hot concentrated sulfuric acid, maintaining performance and integrity at temperatures ranging from 150°C to 200°C, making them suitable for filtering fluids and treating corrosive substances.
Implementation Method 1
the first copolymer comprising polymerized monomeric units A and B... B is a perfluoro (alkyl vinyl)ether compound, a perfluoroalkyl vinyl compound, or a perfluoro alkoxyalkyl vinyl ether compound, each compound having one or more sulfonic acid groups or a salt thereof, one or more sulfonyl fluoride groups, one or more sulfonamide groups, or one or more sulfonate ester groups
Data Source
AI summary
Disclosed are porous membranes including a porous support and a coating comprising a copolymer having monomeric units A and B, and optionally monomeric units C; wherein A is a halogenated vinyl monomer other than tetrafluoroethylene, a halogenated alkyl vinyl ether, or an alkene of the formula CnH2n, wherein n is 1-6; B is a perfluoro (alkyl vinyl)ether compound, a perfluoroalkyl vinyl compound, or a perfluoro alkoxyalkyl vinyl ether compound, each compound having one or more sulfonic acid groups or a salt thereof, one or more sulfonyl fluoride groups, one or more sulfonamide groups, or one or more sulfonate ester groups, and C is vinylidene fluoride. Also disclosed are methods of preparing such porous membranes and methods of treating fluids by the use of these membranes.