Radiation-Curable Composite Membrane for Gas Separation
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Solution Overview
Problem
Current composite membranes for gas separation lack a rapid and efficient process for preparing membranes with good flux, selectivity, and robustness, which are essential for effective gas separation applications.
Innovation Solution
A process involving the application of a radiation-curable composition containing polymerisable dialkylsiloxane and a metal to a porous support, followed by irradiation to form a polymeric layer, and subsequent formation of a discriminating layer, with a specific molar ratio of metal to silicon, to create a composite membrane with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional coating methods are used to prepare composite membranes, then the membrane structure can be formed, but the preparation process is time-consuming and lacks efficiency
Solution Approach 1:
The patent replaces conventional thermal curing methods with radiation-curable technology. The composition is applied to the porous support and then cured using radiation (UV, visible, or infrared) instead of prolonged heating, dramatically reducing the curing time from hours to minutes or seconds while maintaining membrane quality and structural integrity
Solution Approach 2:
The patent changes the curing parameter from thermal energy over extended periods to radiation energy with immediate effect. By using radiation-curable compositions with specific photoinitiators or radiation-sensitive groups, the curing process is accelerated without compromising the membrane's flux, selectivity, or mechanical properties
2Strength
If the polymeric layer is made thicker to improve robustness, then mechanical strength increases, but gas flux decreases
Solution Approach 1:
The patent employs a thin polymeric layer (50-500 nm) that provides sufficient mechanical robustness while maintaining high gas flux. The radiation-curable composition forms a uniform, defect-free thin film that adheres well to the porous support, achieving the optimal balance between thickness for strength and thinness for permeability without requiring thick layers
Solution Approach 2:
The patent creates a composite membrane structure where a thin polymeric layer (50-500 nm) is deposited on a porous support. This composite architecture allows the thin polymeric layer to provide selectivity and sufficient mechanical strength, while the porous support contributes mechanical robustness and maintains high gas flux through its open pore structure, achieving both robustness and high flux simultaneously
3Manufacturing precision
If the discriminating layer is made more selective to improve separation performance, then selectivity increases, but the complexity of the preparation process increases
Solution Approach 1:
The patent achieves high selectivity by carefully controlling the composition parameters of the radiation-curable coating, including the metal-to-silicon molar ratio (at least 0.0005) and the types of polymerisable dialkylsiloxane compounds used. By adjusting these compositional parameters rather than adding complex processing steps, the method achieves CO2/CH4 selectivity greater than 10 while keeping the preparation process relatively simple and scalable
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 composite membranes exhibit improved selectivity and flux, making them suitable for efficient gas separation, particularly in separating gases like CO2 and CH4, with a CO2/CH4 selectivity greater than 10, as demonstrated by exposure to a 13/87 mixture at 6000 kPa and 40°C.
Implementation Method 1
irradiating the radiation-curable composition on the support, thereby forming a polymeric layer comprising dialkylsiloxane groups and a metal on the porous support
Data Source
AI summary
A composite membrane comprising: a. a porous support; b. a polymeric layer comprising dialkylsiloxane groups and a metal, the polymeric layer being present on the porous support; c. a discriminating layer present on the polymeric layer; and d. optionally a protective layer present on the discriminating layer wherein the polymeric layer has a molar ratio of metal:silicon of at least 0.0005.