Polyarylene Ether Sulfone Membranes via Controlled Polycondensation
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Solution Overview
Problem
Existing processes for producing polyarylene ether sulfone polymers result in materials with inadequate mechanical properties and high polydispersity, particularly for membrane applications, and require long reaction times.
Innovation Solution
A process involving a reaction mixture with a dihalogen component, a dihydroxy component, and potassium carbonate, where the potassium carbonate has a volume-average particle size of less than 25 μm, is used for polycondensation in an aprotic polar solvent, allowing for a single-stage reaction that reduces polydispersity and enhances mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional carbonate method with fine potassium carbonate (≤20 μm) is used, then reaction proceeds at reasonable speed, but the resulting polymers exhibit insufficient mechanical properties and high polydispersity
Solution Approach 1:
The patent changes the particle size parameter of potassium carbonate from fine (≤20 μm) to coarse (25-50 μm), which fundamentally alters the reaction mechanism. The larger particles provide a different surface area to volume ratio and dissolution rate, leading to more controlled monomer conversion and reduced polydispersity while maintaining acceptable reaction speeds.
2Strength
If longer reaction time is used, then molecular weight builds up better, but the process becomes economically unviable
Solution Approach 1:
By changing the potassium carbonate particle size to 25-50 μm, the patent achieves faster reaction kinetics that build sufficient molecular weight in 4-12 hours, compared to conventional methods requiring longer times. The altered particle morphology and surface characteristics enable more efficient reaction progress.
3Ease of manufacture
If fine ground sodium carbonate is used as in EP 0 412 499, then polycondensation can proceed, but the polymers obtained exhibit insufficient mechanical properties for membrane applications
Solution Approach 1:
The patent switches from sodium carbonate to potassium carbonate and changes the particle size from fine ground (≤20 μm) to coarse (25-50 μm). This dual parameter change results in polymers with significantly improved mechanical properties suitable for membrane applications, while maintaining process feasibility through the same polycondensation mechanism.
4Productivity
If conventional processes are used, then production can proceed, but complex separation of cyclic oligomers is required
Solution Approach 1:
By using potassium carbonate with particle size 25-50 μm, the patent suppresses cyclic oligomer formation through more controlled reaction kinetics. This eliminates the need for complex separation processes, as the polymers can be directly isolated by filtration and precipitation without requiring additional separation steps.
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 process achieves polyarylene ether sulfone polymers with low polydispersity and improved mechanical properties, suitable for membrane applications, while shortening reaction times and eliminating the need for complex separation of cyclic oligomers.
Implementation Method 1
The reaction mixture (RG) is reacted. The reaction mixture (RG) contains at least one dihalide as component (A1), at least one dihydroxy compound as component (B1), potassium carbonate as component (C), and at least one aprotic polar solvent as component (D).
Data Source
AI summary
The invention relates to a method for producing a polyarylene ether sulfone polymer by reacting a reaction mixture (RG) containing a dihalogen component (A1), a dihydroxy component (B1) and potassium carbonate (C1) having an average volumetric particle size of < 25 µm. The invention also relates to the polyarylene ether sulfone polymers obtained according to said method and to products, such as membranes, which are obtained from said polyarylene ether sulfone polymer and which are produced from the polyarylene ether sulfone polymer.