Crosslinked Polysaccharide Membrane for Gas Separation
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Solution Overview
Problem
Existing gas separation membranes face challenges in reducing thickness without compromising separation factor, limiting the increase in permeation rate.
Innovation Solution
A gas separation membrane with a crosslinked polysaccharide structure, specifically chitosan, having a degree of crystallinity of 17% or less and containing Ag or Cu atoms, which enhances permeability coefficient and separation factor through X-ray diffraction and photoelectron spectroscopy analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of the separation layer is reduced to increase permeation rate, then the permeation rate increases, but the membrane strength and defect resistance deteriorate
Solution Approach 1:
The patent employs an ultrathin separation layer (1-10 μm) supported on a porous substrate, achieving high permeation rates while the porous support provides mechanical strength. The crosslinked polysaccharide structure in the thin film maintains structural integrity despite the reduced thickness, resolving the contradiction between thinness for permeation and strength for durability.
Solution Approach 2:
The membrane uses a composite structure combining a polysaccharide-based separation layer with a porous support layer. The crosslinked polysaccharide network provides both the separation function and enhanced mechanical properties, while the porous support adds structural strength, allowing the thin film to achieve high permeation without sacrificing strength.
2Volume of moving object
If the thickness of the separation layer is reduced to make equipment more compact, then the equipment size decreases, but the separation factor and performance deteriorate
Solution Approach 1:
The ultrathin separation layer (1-10 μm) enables compact equipment design while the crosslinked polysaccharide structure maintains high separation factor by preventing defects and controlling free volume. The crosslinking creates a dense, defect-free network that preserves separation performance even at ultrathin dimensions.
Solution Approach 2:
The patent changes the structural parameters of the polysaccharide by introducing crosslinks, which transforms the physical and chemical properties of the separation layer. This crosslinking allows the membrane to maintain high separation factor at reduced thickness by controlling chain conformation and free volume distribution.
3Manufacturing precision
If a non-porous polymer layer is used to achieve gas separation, then the separation factor improves, but the permeability coefficient and permeation rate are limited
Solution Approach 1:
The patent changes the molecular structure of the polysaccharide through crosslinking, creating a network with optimized free volume and chain conformation. This structural modification enables simultaneous achievement of high separation factor and high permeability by controlling the size and distribution of free volume elements at the molecular level.
Solution Approach 2:
The membrane combines crosslinked polysaccharide with appropriate plasticizers or modifiers to create a composite separation layer that achieves both high separation factor and high permeability. The composite structure allows optimization of both dense network for separation and chain mobility for permeation.
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 membrane achieves a high permeation rate and separation performance for target gases like propylene and CO2, with improved permeability coefficients and separation factors, while maintaining durability.
Implementation Method 1
imparting a suitable crosslinked structure to a polymer that composes the gas separation membrane
Implementation Method 2
the degree of crystallinity as represented by the following equation (1) is 17% or less
Implementation Method 3
Permeation rate is expressed as (permeability coefficient of gas)/(thickness of separation layer)
Implementation Method 4
when having carried out X-ray diffraction analysis on the gas separation membrane
Implementation Method 5
the scattering intensities of the crystalline peaks and Ia represents the sum of the integral values of the scattering intensities of the amorphous halo
Implementation Method 6
when having carried out X-ray photoelectron spectroscopy on the gas separation membrane
Data Source
AI summary
Provided is a gas separation membrane containing polysaccharides and being characterized by having a crystallinity of 17% or lower, the crystallinity being represented by equation (1) below: (1) Crystallinity (%)=[Ic/(Ic+Ia)]×100 (In equation (1), Ic is the sum of the integrals of the scattering intensities of crystalline peaks obtained from X-ray diffraction analysis of the gas separation membrane, and Ia is the sum of the integrals of the scattering intensities of the amorphous halo).