Polysulfone UF Membranes via N-Acyl-Morpholine Solvent
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Solution Overview
Problem
Current solvents used for sulfone polymers in membrane production, such as ultrafiltration (UF) membranes, face challenges with turbidity and limited ability to achieve high water permeability and small pore size, which are essential for effective UF membrane performance.
Innovation Solution
A solution comprising a sulfone polymer, a water-soluble polymer, and N-acyl-morpholine is used to create a solvent system that allows for the production of membranes with high mechanical stability and separation efficiency, where the sulfone polymer includes aromatic units and the water-soluble polymer enhances porosity, and N-acyl-morpholine serves as a primary solvent with co-solvents like N-formyl-pyrrolidine or dimethylacetamide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional solvents (NMP, DMAC, DMAD, DMSO) are used for dissolving sulfone polymers, then the polymer can be dissolved, but the solutions exhibit turbidity caused by low molecular weight fractions and the membranes achieve limited water permeability
Solution Approach 1:
The patent changes the chemical parameters of the solvent system by using N-acyl-morpholine (particularly N-formyl-morpholine) instead of conventional solvents like NMP or DMAC. This parameter change in solvent chemistry eliminates turbidity while enabling high water permeability in the resulting UF membranes, directly resolving the contradiction between solution clarity and membrane performance
Solution Approach 2:
The patent creates a composite solvent system comprising N-acyl-morpholine in combination with co-solvents (N-formyl-pyrrolidine, dimethylacetamide, or dimethylformamide). This composite approach allows the primary solvent N-acyl-morpholine to eliminate turbidity while co-solvents support the dissolution and membrane formation process, achieving both clarity and high permeability
2Manufacturing precision
If the pore size is made small to withhold low molecular weight polymers, then separation efficiency improves, but water permeability decreases
Solution Approach 1:
The patent changes the physical-chemical parameters of the membrane structure by using a specific sulfone polymer with controlled molecular weight distribution and composition (including aromatic units). This parameter control allows formation of membranes with precise molecular weight cutoffs that simultaneously maintain high water permeability, resolving the trade-off between separation precision and flow rate
3Strength
If high content of sulfone polymer is used in the solution, then membrane mechanical stability improves, but solution turbidity increases
Solution Approach 1:
The patent changes the solvent chemical parameters by using N-acyl-morpholine which has superior dissolving capacity for sulfone polymers. This allows preparation of high-concentration polymer solutions (achieved through improved solubility parameters) that remain clear and transparent, enabling fabrication of mechanically stable membranes without turbidity-related defects
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 resulting membranes exhibit improved mechanical stability, high water permeability, and precise molecular weight cutoffs, enabling effective separation and purification with reduced turbidity and enhanced performance compared to traditional methods.
Implementation Method 1
dissolving sulfone polymers and a water-soluble polymer in a solvent... The selection of the solvent is essential to the process and has impact on the properties of the obtained membrane
Implementation Method 2
coagulating the sulfone polymer from such solvent and further post-treatment steps
Implementation Method 3
The porosity should allow a high water permeation through the membrane... the UF membrane should withhold any polymer even low molecular weight polymers found in the water
Data Source
AI summary
Solution comprising a sulfone polymer, a water-soluble polymer and a N-acyl-morpholine of formula I wherein R1 is a hydrogen atom or a C1- to C3 alkyl group.