Polyamide Membrane Streak Recesses for Permeation
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Solution Overview
Problem
Conventional polyamide porous membranes exhibit decreased fluid permeation performance, particularly in the molecular weight cut-off range of 200 to 50,000, making it difficult to achieve appropriate filtration performance.
Innovation Solution
A polyamide porous membrane with a dense layer featuring streak-like recessed portions extending in one direction, having an orientation angle of 0 to 5.0° or 175.0 to 180.0° and an orientation intensity of 1.5 to 2.0, produced using a combination of thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) methods, followed by uniaxial stretching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyamide porous membranes are used with molecular weight cut-off in the range of 200 to 50,000, then organic solvent resistance is maintained, but fluid permeation performance decreases
Solution Approach 1:
The invention applies local quality by creating a dense layer with a specific streak-like recessed portion structure on the membrane surface. This localized structural feature (streak-like recessed portions with specific orientation angle and intensity) improves fluid permeation performance in the molecular weight cut-off range of 200 to 50,000 while maintaining the organic solvent resistance provided by the polyamide material throughout the membrane structure.
2Measurement precision
If the molecular weight cut-off is reduced to improve separation precision, then separation performance improves, but fluid permeation performance decreases
Solution Approach 1:
The invention changes the structural parameters of the membrane surface by forming streak-like recessed portions with specific orientation angles (0 to 5.0° or 175.0 to 180.0°) and orientation intensity (1.5 to 2.0). This parameter change in the surface morphology allows the membrane to achieve both improved separation precision and maintained fluid permeation performance, resolving the typical trade-off between these two characteristics.
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 membrane achieves improved fluid permeation performance, enhanced productivity, energy savings, and lower production costs, while maintaining resistance to organic solvents and preventing fouling by hydrophobic substances.
Implementation Method 1
Porous membranes are used as filtration membranes in various fields... nanofiltration membranes and ultrafiltration membranes have been put into practical use... for removal of bacteria, viruses, pesticides, odorous components, and hardness components
Implementation Method 2
polyamide resins have high organic solvent resistance... separation membranes formed using materials with high organic solvent resistance have been reported
Implementation Method 3
a polyamide porous membrane formed by using thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) in combination
Data Source
AI summary
An object of the present invention is to provide a polyamide porous membrane having improved fluid permeation performance. A polyamide porous membrane having a dense layer formed on at least one surface, wherein the polyamide porous membrane has a streak-like recessed portion extending in one direction of a surface of the dense layer, and the streak-like recessed portion has an orientation angle of 0 to 5.0° or 175.0 to 180.0° and an orientation intensity of 1.5 to 2.0 according to predetermined orientation analysis.