Crosslinked Polymer Membranes UV Crosslinking
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Solution Overview
Problem
Current gas separation membranes face challenges with long-term stability, particularly in the presence of water, and suffer from a trade-off between permeability and selectivity, with existing crosslinking methods being inefficient and costly, and often resulting in inferior performance.
Innovation Solution
Development of crosslinked polymer compositions with specific structural units that can be exposed to energetic radiation to form crosslinks, enhancing selectivity and durability while maintaining commercially viable permeability, using polymers with benzylic hydrogens and carbonyl groups for crosslinking reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crosslinking is performed using conventional methods (chemical crosslinkers, thermal treatment), then selectivity and durability are improved, but manufacturing complexity and cost increase, and processing becomes more difficult
Solution Approach 1:
The patent replaces conventional chemical crosslinking methods (using crosslinking agents like epichlorohydrin or complex thermal treatments) with direct UV irradiation. The polymer contains built-in photoreactive groups (benzylic hydrogens and carbonyl groups) that undergo crosslinking upon UV exposure without requiring additional chemical crosslinkers or complex processing equipment, thereby simplifying the manufacturing process while achieving durable crosslinked membranes
Solution Approach 2:
The polymer is designed with self-contained photoreactive functional groups (benzylic hydrogens and carbonyl groups) that enable autonomous crosslinking when exposed to UV light. The polymer structure itself provides the necessary reactive sites for crosslinking, eliminating the need for external crosslinking agents or catalysts, thus reducing manufacturing complexity and cost
2Productivity
If highly permeable polymers are used, then gas permeability is improved, but selectivity deteriorates due to the permeability-selectivity trade-off
Solution Approach 1:
The patent changes the physical-chemical parameters of the polymer by introducing crosslinked structures through UV irradiation. This creates a three-dimensional network that modifies the free volume distribution and chain mobility, allowing highly permeable base polymers to achieve enhanced selectivity after crosslinking without sacrificing their inherent high permeability characteristics
3Reliability
If polyimide systems are used, then selectivity is improved, but hydrolytic stability deteriorates due to susceptibility to water-induced degradation
Solution Approach 1:
The patent creates a composite structure within the polyimide system by incorporating photoreactive functional groups (benzylic hydrogens and carbonyl groups) into the polymer chain. Upon UV irradiation, these groups form crosslinked structures that create a more resistant network against hydrolytic degradation, effectively combining the high selectivity of polyimides with improved water stability through the crosslinked architecture
4Stability of the object's composition
If specialized monomers (e.g., benzocyclobutene-based monomers) are incorporated for crosslinking, then thermal crosslinking is achieved, but manufacturing cost increases and gas separation performance deteriorates
Solution Approach 1:
The patent substitutes thermal crosslinking mechanisms (which require specialized monomers like benzocyclobutene) with UV-photoinduced crosslinking. The polymer contains built-in photoreactive groups that enable crosslinking upon UV exposure, eliminating the need for specialized thermal-crosslinkable monomers and their associated processing requirements, thereby maintaining excellent gas separation performance while achieving crosslinked durability
Solution Approach 2:
The patent uses simple, readily available photoreactive functional groups (benzylic hydrogens and carbonyl groups) that are already present in common polymer structures, replacing expensive specialized monomers. These functional groups provide sufficient crosslinking capability without requiring complex or costly monomer synthesis, achieving cost-effective crosslinked membranes with maintained performance
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 crosslinked polymer membranes exhibit improved selectivity and durability, resisting hydrolytic instability and swelling, thus providing enhanced performance in gas separation applications.
Implementation Method 1
The crosslinking of membrane materials by ultraviolet (UV) irradiation
Implementation Method 2
exposing to UV radiation the polymer composition of formula (I) to form a crosslinked polymer composition of formula (II)
Data Source
AI summary
Gas separation membrane compositions including at least one crosslinked polymer, gas separation membranes made of such compositions, methods for making such gas separation membranes, and methods of using such membranes to separate gases are described. In one embodiment, the crosslinked polymer includes polyarylene ethers (PAE).