UV-Treated Polyimide Membranes for Gas Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Commercial gas separation membranes face challenges in achieving high permeability and selectivity simultaneously, with existing methods requiring heat treatment or functional groups cross-linkable to UV light, which can be cumbersome or inefficient.
Innovation Solution
A polyimide membrane with the formula derived from pyromellitic dianhydride, 2,4,6-trimethyl-1,3-phenylenediamine, and 4,4'-methylene bis(2,6-dimethylaniline) is synthesized through a two-step condensation reaction and solution chemical imidization process, followed by UV treatment to enhance permeability and selectivity without the need for heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If heat treatment is applied to achieve high permeability, then permeability is improved, but process complexity increases
Solution Approach 1:
The patent replaces thermal treatment (heat) with UV irradiation to achieve cross-linking and enhance permeability. This substitution eliminates the need for complex heat treatment processes while achieving the same functional outcome of improving gas permeability through controlled cross-linking of the polyimide matrix.
Solution Approach 2:
The patent changes the treatment parameter from thermal energy to UV radiation energy. By using UV irradiation instead of heat treatment, the process achieves cross-linking at lower temperatures with simpler equipment, thereby improving permeability without increasing process complexity.
2Manufacturing precision
If functional groups cross-linkable to UV light are incorporated, then selectivity is improved, but polymer synthesis complexity increases
Solution Approach 1:
The patent introduces specific functional groups (carbonyl or sulfonyl) at localized positions within the polyimide chain that are capable of UV-induced cross-linking. This localized incorporation of reactive groups allows selective cross-linking in the regions that need enhanced selectivity, without requiring complex modifications throughout the entire polymer structure.
Solution Approach 2:
The patent creates a composite polyimide structure combining standard polyimide segments with UV-reactive functional groups. This composite approach allows the material to maintain the base polyimide's good permeability while adding cross-linking capability for enhanced selectivity, avoiding the need to redesign the entire polymer synthesis process.
3Quantity of substance
If membrane area is increased to achieve high permeability, then permeability is improved, but capital cost increases
Solution Approach 1:
The patent changes the physical-chemical parameters of the membrane material through UV-induced cross-linking, which enhances the permeability coefficient at the material level. This allows achieving high overall permeability with smaller membrane areas, thereby reducing capital costs without needing to scale up the physical membrane size.
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 polyimide membrane exhibits high CO2 and H2 permeabilities exceeding commercial membranes, with UV treatment significantly increasing selectivity for CO2/CH4 separation, demonstrating improved performance without the need for heat treatment.
Implementation Method 1
selectivity can be tuned via cross-linking in the presence of UV light
Implementation Method 2
Separation is based on a solution-diffusion mechanism. This mechanism involves molecular-scale interactions of the permeating gas with the membrane polymer
Data Source
AI summary
Polyimide membranes are provided that provide extremely high permeability. The polyimides do not contain carbonyl or sulfonyl functional groups. These membranes are useful in separating gases including the separation of gas pairs including carbon dioxide/methane, hydrogen/methane and propylene/propane as well as other gas mixtures. The membrane selectivity can be adjusted by exposure to ultraviolet light.