Hybrid Crosslinked Polymer Membrane for CO2 Separation
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Solution Overview
Problem
Existing polymer membranes used for separating carbon dioxide from natural gas face challenges such as reduced CO2 permeability and selectivity due to plasticization under high pressure, and inefficient crosslinking processes that affect durability and chemical resistance.
Innovation Solution
A hybrid crosslinked polymer membrane is developed, comprising 70-90% glassy polymer with a first functional group and 10-30% ladder-structured polysilsesquioxane with a second functional group capable of reacting with the first. The membrane is formed by dissolving the polymer composition in an organic solvent, casting into a membrane shape, and thermally treating to create a crosslinked structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure swing adsorption (PSA) process is used to remove carbon dioxide from natural gas, then carbon dioxide can be selectively removed, but the process becomes expensive and uneconomical for small-scale refining
Solution Approach 1:
The patent changes the operational parameters by using a membrane separation process instead of PSA, operating at high pressure (30-100 atm) to achieve selective CO2 permeation. This parameter change enables small-scale applications to be economically viable while maintaining high CO2 removal efficiency
Solution Approach 2:
The patent replaces the mechanical PSA system with a membrane-based separation system that uses pressure-driven permeation. This substitution eliminates the complexity and cost of PSA equipment while achieving the same separation goal through the selective permeability of the crosslinked polymer membrane
2Reliability
If crosslinking of polyimide using an amine crosslinking agent is performed, then plasticization resistance is improved, but free volume decreases which reduces CO2 permeability
Solution Approach 1:
The patent creates a composite crosslinked structure by reacting polyimide with a diisocyanate crosslinking agent. This composite approach combines the plasticization resistance of crosslinked networks with the high CO2 permeability of polyimide, achieving both improved reliability and maintained quantity of CO2 transport
Solution Approach 2:
The patent changes the crosslinking chemistry from amine-based to isocyanate-based crosslinking. This parameter change in the crosslinking mechanism preserves more free volume compared to amine crosslinking, thereby maintaining high CO2 permeability while still achieving adequate plasticization resistance
3Reliability
If crosslinked membranes using bromination/debromination are employed, then plasticization resistance is enhanced, but process efficiency becomes poor due to multiple treatment steps
Solution Approach 1:
The patent extracts the complex bromination/debromination steps from the process and replaces them with a single isocyanate crosslinking step. This removal of unnecessary steps maintains the plasticization resistance benefit while dramatically improving process efficiency and productivity
Solution Approach 2:
Instead of using the conventional bromination/debromination route to achieve crosslinking, the patent inverts the approach by using direct isocyanate crosslinking of polyimide. This inverted methodology achieves the same plasticization resistance with a single step process, eliminating the need for multiple treatment steps
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 hybrid crosslinked polymer membrane exhibits enhanced CO2 permeability, improved plasticization resistance, increased chemical resistance, and durability, effectively addressing the limitations of existing membranes in gas separation applications.
Implementation Method 1
a crosslinked structure formed by a reaction of the first functional group and the second functional group
Implementation Method 2
dissolving a polymer composition comprising 70 to 90% by weight of a glassy polymer having a first functional group and 10 to 30% by weight of a ladder-structured polysilsesquioxane having a second functional group in an organic solvent
Implementation Method 3
thermally treating the hybrid polymer precursor membrane obtained in step (2) to form a crosslinked structure
Data Source
AI summary
A hybrid crosslinked polymeric membrane and a process for fabricating the same are provided. Specifically, the hybrid crosslinked polymer membrane comprises a glassy polymer and a ladder-structured polysilsesquioxane and has a crosslinked structure. The hybrid crosslinked polymer membrane can have an excellent permeability of carbon dioxide by virtue of an increase in the free volume and enhanced plasticization resistance, chemical resistance, and durability.