HFIP-Modified Polyimide Gas Separation Membrane
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Solution Overview
Problem
The existing gas separation membranes using polyimide materials are limited in chemical structure, making it difficult to design for strength and separation performance, and they are not easily soluble in organic solvents, which hampers their formability and effectiveness.
Innovation Solution
A gas separation membrane incorporating a polyimide with a 2-hydroxy-1,1,1,3,3,3-hexafluoroisopropyl group (HFIP) that is soluble in organic solvents, particularly polar solvents, enhancing separation performance and allowing for the design of membranes with improved strength and formability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyimide materials are used for gas separation membranes, then heat resistance and strength are improved, but solubility in organic solvents deteriorates
Solution Approach 1:
The invention modifies the chemical structure parameters of polyimide by introducing a 2-hydroxy-1,1,1,3,3,3-hexafluoroisopropyl group (HFIP) at specific positions in the repeating unit. This structural parameter change enables the polymer to maintain its strength characteristics while gaining solubility in organic solvents, resolving the contradiction between strength and ease of manufacture.
2Ease of manufacture
If chemical structure is limited to conventional diamine and carboxylic dianhydride, then synthesis is simplified, but design flexibility for strength and separation performance deteriorates
Solution Approach 1:
The invention segments the polyimide structure into distinct functional components: a base polyimide framework providing strength, and HFIP groups providing solubility and separation performance. This segmentation allows independent optimization of each component's properties while maintaining overall synthesis simplicity through conventional polycondensation methods.
Solution Approach 2:
The invention creates a composite chemical structure within the polyimide repeating unit, combining the robust imide ring structure with the solubilizing HFIP side group. This composite approach enables the material to exhibit both the strength of conventional polyimides and the enhanced solubility and separation performance required for membrane applications.
3Reliability
If hexafluoroisopropylidene group is introduced to enhance gas separation performance, then permeability and selectivity are improved, but chemical structure limitation persists
Solution Approach 1:
The invention changes the chemical structure from containing a hexafluoroisopropylidene group (-C(CF3)2-) to containing a 2-hydroxy-1,1,1,3,3,3-hexafluoroisopropyl group (HFIP). This parameter change in the chemical structure maintains the beneficial gas separation performance while enabling improved solubility and broader design flexibility for membrane fabrication.
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 HFIP-containing polyimide membrane exhibits superior gas separation performance, with increased solubility in organic solvents enabling the formation of membranes with enhanced strength and separation efficiency.
Implementation Method 1
The separation of gas is a technique for selectively separating a gas with the aid of the presence or absence of permeation and the differences in permeation rate according to the kind of gas which is to permeate through a gas separation membrane
Data Source
AI summary
[Problem] Diamine and carboxylic dianhydride for polymerizing a hexafluoroisopropylidene group-containing polyimide are limited in chemical structure when developed into a polyimide membrane, so that it is difficult to design a chemical structure with consideration paid to the strength and separation performance of a gas separation membrane. A gas separation membrane easily soluble in an organic solvent, excellent in formability so as to be readily usable for a gas separation membrane, and excellent in gas separation performance is obtained. [Solution] A gas separation membrane, including: a polyimide that contains a repeating unit represented by general formula (1). [In the formula (1), R1 is a divalent organic group and R2 is a tetravalent organic group, R1 containing a 2-hydroxy-1,1,1,3,3,3-hexafluoroisopropyl group (-C(CF3)2OH).]