Crosslinked Poly(ether-b-amide) Membranes for Gas Separation

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Solution Overview

Problem

Current polymeric membranes for natural gas separation face challenges in achieving high CO2 permeability, thermal stability, and CO2/CH4 selectivity, while also being prone to plasticization and physical aging.

Innovation Solution

Crosslinked poly(ether-b-amide) membranes are developed using a diisocyanate polyether, where the poly(ether-b-amide) copolymer forms urethane crosslinks with the diisocyanate polyether, enhancing mechanical strength and resistance to plasticization, and improving gas separation selectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polymeric membranes are used for gas separation, then permeability and selectivity are achieved, but physical aging and plasticization occur

Engineering Contradiction:
Improveresistance to plasticizationVSAvoidphysical aging
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses a composite crosslinked structure combining poly(ether-b-amide) copolymer with diisocyanate polyether crosslinker. This composite approach creates a network structure that resists plasticization and physical aging while maintaining gas separation performance. The crosslinked composite material exhibits superior stability compared to conventional uncrosslinked polymeric membranes.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If conventional polymeric membranes are used for CO2 separation, then CO2/CH4 selectivity is achieved, but CO2 permeability is limited

Engineering Contradiction:
ImproveCO2 permeabilityVSAvoidCO2/CH4 selectivity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent modifies the membrane structure by introducing crosslinks through diisocyanate polyether, which changes the physical and chemical parameters of the poly(ether-b-amide) matrix. This parameter change creates a more open structure with enhanced CO2 permeability while maintaining selectivity through the specific crosslinking architecture and urethane bond formation.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If polymeric membranes are designed for gas separation, then permeability is improved, but thermal stability decreases

Engineering Contradiction:
Improvegas permeabilityVSAvoidthermal stability
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The crosslinked composite structure combines the gas permeability of poly(ether-b-amide) with the thermal stability enhancement provided by the diisocyanate crosslinking network. The urethane crosslinks formed during crosslinking create a thermally stable framework that maintains membrane performance at elevated temperatures while preserving gas separation capability.

Inventive Principle:
Principle #40Composite materials

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 membranes exhibit significantly increased CO2 permeability and CO2/CH4 selectivity, along with improved mechanical properties and resistance to plasticization, effectively separating sour gas components in natural gas.

Implementation Method 1

the poly(ether-b-amide) copolymer forms urethane crosslinks with the diisocyanate polyether

Methodology Applied
Scientific EffectUrethane crosslinking: Chemical Bonding

Implementation Method 2

The crosslinked membranes exhibit significantly increased CO2 permeability and CO2/CH4 selectivity

Methodology Applied
Scientific EffectGas permeation: Permeation

Data Source

PatentEP3661633B1Crosslinked polymeric blended membranes for gas separation
Publication Date: 2021.01.20 SAUDI ARABIAN OIL CO
  • EP3661633B1 patent drawingFigure 1
  • EP3661633B1 patent drawingFigure 2~3
  • EP3661633B1 patent drawingFigure 4~5

AI summary

Methods of making a gas separation membrane, a gas separation membrane, and method of gas separation. The gas separation membrane includes cross-linked poly(ether-b-amide) copolymer, in which the poly(ether-b-amide) copolymer comprise urethane crosslinks which is the reaction product of poly(ether-b-amide) copolymer and diisocyanate polyether according to formula (I).