Carbon Molecular Sieve Membrane Processing via Homogeneous Dehydrohalogenation
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Solution Overview
Problem
Conventional methods for producing carbon molecular sieve (CMS) membranes face challenges in processability due to the insolubility of precursor polymers in common solvents, leading to uneven dehalogenation and production inefficiencies.
Innovation Solution
A method involving the homogeneously dehydrohalogenation of precursor polymers using an organic amine base to form partially dehydrohalogenated polymers, which are soluble in solvents, followed by pyrolysis to create CMS membranes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional precursor polymers are used for producing CMS membranes, then the production process can proceed, but the polymers are insoluble in common solvents leading to slow production speed and processing difficulties
Solution Approach 1:
The patent modifies the chemical structure of precursor polymers by introducing soluble side chains or modifying the polymer backbone to improve solubility in common solvents. This parameter change in molecular structure allows the polymers to dissolve properly, enabling solution processing methods and significantly improving production speed while maintaining CMS membrane performance
Solution Approach 2:
The patent employs composite precursor polymers that combine carbon-forming moieties with solvent-compatible side chains or functional groups. This composite structure allows the polymer to maintain its ability to form carbon molecular sieves upon pyrolysis while simultaneously achieving good solubility and processability in conventional solvents
2Manufacturing precision
If heterogeneous dehalogenation is used on precursor polymers, then dehalogenation can occur, but it causes uneven dehalogenation with extensive dehalogenation at the surface and limited dehalogenation near the center
Solution Approach 1:
The patent applies preliminary action by first dissolving the precursor polymer in a suitable solvent to create a homogeneous solution before dehalogenation. This preliminary dissolution step ensures uniform distribution of polymer chains and reagents, allowing subsequent dehalogenation to proceed uniformly throughout the entire polymer matrix rather than creating surface-only reactions
Solution Approach 2:
The patent uses a solvent as an intermediary medium to facilitate uniform dehalogenation. The solvent acts as a mediator that allows homogeneous contact between the polymer chains and dehalogenating agents, ensuring consistent reaction conditions throughout the solution and producing uniformly dehalogenated polymers with controlled double bond formation
3Ease of manufacture
If homogeneous dehydrohalogenation is applied to dissolved precursor polymers, then the polymers become soluble in common solvents, but this requires dissolving the polymer first which adds a step to the process
Solution Approach 1:
The patent modifies the chemical parameters of the precursor polymer by incorporating soluble side chains or modifying the polymer architecture to enhance intrinsic solubility. This parameter change in molecular structure allows the polymer to dissolve readily in common solvents, and the dehalogenation can then proceed in the dissolved state, making the additional dissolution step beneficial rather than burdensome
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 enhances the solubility and processability of CMS membranes, allowing for efficient production without melting and improving separation performance.
Implementation Method 1
homogeneously dehydrohalogenating the dissolved halogenated precursor polymer with an organic amine base to form a partially dehydrohalogenated polymer
Implementation Method 2
pyrolyzing the thin film to form the carbon molecular sieve membrane
Data Source
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AI summary
A method of forming a carbon molecular sieve membrane includes dissolving a halogenated precursor polymer in a solvent, thereby forming a dissolved halogenated precursor polymer. Homogeneously dehydrohalogenating the dissolved halogenated precursor polymer with an organic amine base to form a partially dehydrohalogenated polymer. Forming a thin film from the partially dehydrohalogenated polymer. Pyrolyzing the thin film to form the carbon molecular sieve membrane.