Polyether Purification via Adsorbent Solid-Liquid Separation
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Solution Overview
Problem
Conventional methods for purifying aromatic polyethers, such as polyetherimides and polyethersulfones, face challenges in efficiently removing alkali metal halides and catalysts, leading to contamination and reduced recovery rates due to emulsification issues during water extraction processes.
Innovation Solution
A method involving the adsorption of guanidinium catalysts and alkali metal halides in the substantial absence of water, using a polymerization mixture with less than 0.005 weight percent water, where the catalyst is adsorbed onto alkali metal halide, allowing for their removal through solid-liquid separation without water washing, thereby preventing emulsification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If water extraction methods are used to remove alkali metal halide and catalyst, then these contaminants are transferred to the aqueous phase, but emulsions form and prevent efficient phase separation
Solution Approach 1:
The patent extracts and removes the harmful contaminants (alkali metal halide and catalyst) from the polymer solution using a solid adsorbent material. This solid-liquid extraction method avoids the emulsion formation problem inherent in water extraction, enabling both high purity recovery and rapid separation.
Solution Approach 2:
The patent introduces a solid adsorbent as an intermediary substance to facilitate the removal of contaminants. This adsorbent acts as a mediator between the polymer solution and the contaminants, allowing efficient removal without direct water-polymer interaction that causes emulsification.
2Manufacturing precision
If water extraction is performed to remove contaminants, then alkali metal halide and catalyst are transferred to aqueous phase, but recovery efficiency decreases due to emulsification
Solution Approach 1:
The patent extracts contaminants using a solid adsorbent that selectively binds alkali metal halide and catalyst, removing them from the polymer solution without the emulsion formation that plagues water extraction methods. This enables complete recovery of both the polymer and contaminants.
Solution Approach 2:
The patent employs a disposable solid adsorbent material that can be used once to remove contaminants and then discarded or regenerated. This single-use approach eliminates the need for complex water separation and recovery systems, improving overall recovery efficiency.
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
This approach effectively reduces the presence of catalysts and alkali metal halides in the polymer solution, enhancing the purity and recovery efficiency, and avoids the formation of emulsions, facilitating faster phase separation and improved production rates.
Implementation Method 1
the polymerization mixture is subjected to a second temperature to allow adsorption of the guanidinium catalyst with the alkali metal halide to form an adsorbed component
Data Source
AI summary
A method for the purification of aromatic polyether polymers prepared by a halide displacement polymerization process comprises adsorbing the catalyst with an alkali metal halide to form an adsorbent component and then removing the adsorbent component. Mixtures resulting from this method are also discussed.