Hollow Fiber Carbon Membrane Crosslinking for Shape Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for producing hollow fiber carbon membranes using polyphenylene oxide result in impaired moldability and gas separation performance due to the melting of polyphenylene oxide during infusibilization treatment, leading to crushing and breakage of hollow fibers, and require complex processes.
Innovation Solution
A membrane-forming dope with polyphenylene oxide and sulfur is prepared, spun using a non-solvent induced separation method, followed by crosslinking at 200-240°C, infusibilization at 250-350°C, and carbonization at 450-850°C, preventing melting and ensuring excellent moldability and gas separation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyphenylene oxide is used as a raw material for hollow fiber carbon membranes, then cost is reduced and moldability is improved, but the hollow fiber shape is impaired due to melting during infusibilization treatment
Solution Approach 1:
Crosslinking treatment is performed before infusibilization treatment to prevent melting. The crosslinking creates a network structure that maintains the hollow fiber shape during subsequent high-temperature infusibilization, allowing polyphenylene oxide to be used without shape impairment.
Solution Approach 2:
The addition of sulfur changes the thermal properties of polyphenylene oxide by forming crosslinked structures. This parameter change enables the material to withstand infusibilization temperatures without melting, resolving the contradiction between cost-effectiveness and shape maintenance.
2Device complexity
If conventional two-step heating process is used for polyphenylene oxide, then production process is simplified, but hollow fibers undergo crushing and breakage due to melting
Solution Approach 1:
Crosslinking treatment is introduced as a preliminary step before infusibilization to prevent the crushing and breakage that would otherwise occur during the two-step heating process. This maintains hollow fiber integrity while preserving process simplicity.
3Manufacturing precision
If sulfur is added to membrane-forming dope, then crosslinking prevents melting during infusibilization, but additional material cost is incurred
Solution Approach 1:
Sulfur is added in small amounts (0.1-5 wt%, preferably 0.5-2 wt%) to achieve crosslinking. This minimal addition provides the necessary shape stability during infusibilization while keeping the additional material cost low, making the approach economically viable.
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 method prevents melting and breakage of hollow fibers, achieving excellent moldability and high gas separation performance for hollow fiber carbon membranes without complex processes.
Implementation Method 1
performing a crosslinking treatment at 200 to 240° C. in the air
Implementation Method 2
preparing the membrane-forming dope for carbon membranes into a hollow shape by means of a spinning method in accordance with a non-solvent induced separation method
Implementation Method 3
performing an infusibilization treatment by heating at 250 to 350° C.
Implementation Method 4
performing a carbonization treatment by heating at 450 to 850° C. in an inert atmosphere or under vacuum
Data Source
AI summary
A hollow fiber carbon membrane is produced by preparing a membrane-forming dope for carbon membranes by dissolving polyphenylene oxide in an amount giving a concentration of 15 to 40 wt. % in the membrane-forming dope, and sulfur in an amount giving a ratio of 0.2 to 3.0 wt. % based on the polyphenylene oxide, in a solvent capable of dissolving these components; preparing the membrane-forming dope for carbon membranes into a hollow shape by means of a spinning method in accordance with a non-solvent induced separation method using a double annular nozzle; performing a crosslinking treatment at 200 to 240° C. in the air; then performing an infusibilization treatment by heating at 250 to 350° C.; and further performing a carbonization treatment by heating at 450 to 850° C. in an inert atmosphere or under vacuum.