Perfluorodioxolane Copolymer Membranes for Gas Separation
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Solution Overview
Problem
Current gas separation membranes, such as those made from perfluoropolymers like Hyflon® AD and Teflon® AF, suffer from low selectivity for gas pairs like H2/CH4, He/CH4, CO2/CH4, and N2/CH4, despite having high chemical resistance and flux, limiting their industrial application.
Innovation Solution
The use of copolymers formed from specific perfluorodioxolane monomers, particularly perfluoro-2-methylene-1,3-dioxolane and perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolane, in the selective layer of the membrane, which enhances selectivity while maintaining high flux and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If copolymer membranes containing perfluorodioxolane monomers are used, then gas selectivity is improved, but membrane complexity increases
Solution Approach 1:
The patent employs copolymer membranes composed of perfluorodioxolane monomers combined with other fluorinated monomers to achieve superior gas separation performance. The composite structure integrates different monomer units with complementary properties, where perfluorodioxolane provides high selectivity while other monomers contribute to membrane stability and processability, resolving the contradiction between enhanced selectivity and increased complexity.
Solution Approach 2:
The patent optimizes the compositional parameters of the copolymer system by varying the ratio of perfluorodioxolane monomers to other fluorinated monomers. This parameter adjustment allows tuning of the membrane's gas permeability and selectivity characteristics, achieving high H2/CH4, CO2/CH4, and N2/CH4 selectivities while maintaining acceptable membrane complexity through controlled composition design.
2Reliability
If traditional perfluoropolymer membranes are used, then chemical resistance is improved, but gas selectivity deteriorates
Solution Approach 1:
The patent creates composite copolymer systems that integrate perfluorodioxolane monomers (providing high gas selectivity) with fluorinated monomers known for chemical resistance (maintaining reliability). This composite approach allows the membrane to simultaneously achieve superior gas separation performance and maintain the chemical stability characteristic of perfluoropolymers, effectively resolving the contradiction between selectivity and chemical resistance.
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
These copolymers achieve higher selectivity for gas separation compared to traditional membranes, making them suitable for industrial applications such as separating nitrogen, helium, carbon dioxide, and hydrogen from methane, and are thermally stable with high chemical resistance.
Implementation Method 1
passing the gas mixture across a separation membrane having a feed side and a permeate side, the separation membrane having a selective layer comprising a copolymer formed from at least two perfluorodioxolane monomers
Implementation Method 2
providing a driving force for transmembrane permeation
Data Source
AI summary
Disclosed herein is a process for separating components of a gas mixture using gas-separation copolymer membranes. These membranes use a selective layer made from copolymers of perfluorodioxolane monomers. The resulting membranes have superior selectivity performance for gas pairs of interest while maintaining fast gas permeance compared to membranes prepared using conventional perfluoropolymers, such as Teflon® AF, Hyflon® AD, and Cytop®.