Dense-Surface Poly(4-Methyl-1-Pentene) Membrane for Gas Permeability
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Solution Overview
Problem
Conventional separation membranes made from poly(4-methyl-1-pentene) suffer from insufficient solvent resistance and gas permeability, with membranes having high strength exhibiting poor porosity, and vice versa.
Innovation Solution
A separation membrane comprising poly(4-methyl-1-pentene) with a dense layer and a lamellar crystal area ratio of 5 to 50% on one surface, enhancing solvent resistance and gas permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If poly(4-methyl-1-pentene) membrane is made with dense structure to improve solvent resistance, then gas permeability deteriorates
Solution Approach 1:
The membrane is designed with a dense layer on the solvent-contact surface to provide high solvent resistance, while the interior maintains a porous structure to ensure gas permeability. This local differentiation of structure allows each region to optimize its function: the dense surface layer blocks solvent penetration while the porous interior facilitates gas transport.
Solution Approach 2:
The membrane combines poly(4-methyl-1-pentene) polymer matrix with a controlled porous structure to create a composite material that exhibits both solvent resistance and gas permeability. The composite structure integrates the dense polymer regions for solvent barrier properties with controlled pore networks for gas transport pathways.
2Productivity
If membrane porosity is increased to improve gas permeability, then mechanical strength deteriorates
Solution Approach 1:
The membrane structure differentiates between surface and interior regions: the surface contains a dense layer with high polymer concentration for mechanical strength, while the interior develops a porous structure for gas permeability. This local quality variation allows the membrane to simultaneously achieve high strength and high gas permeability without compromising either property.
3Strength
If conventional polyolefin-based membrane is used to achieve high strength, then solvent resistance deteriorates
Solution Approach 1:
The invention changes the critical parameter of surface density by forming a dense layer on the membrane surface through controlled phase separation during fabrication. This parameter change in the surface region provides high solvent resistance while the bulk material maintains its mechanical strength properties, resolving the contradiction between strength and solvent resistance.
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 high solvent resistance and gas permeability, with a N2 permeability of 5 GPU or more at 100 kPa and a gas separation coefficient α(CO2/N2) of 1.0 or more, suitable for gas-liquid separation applications.
Implementation Method 1
a polymer solution in which a polyolefin-based polymer is dissolved in a good solvent is extruded from a spinneret at a temperature higher than the melting point of a polyolefin resin, and this polymer solution is brought into contact with a cooling solvent to form a membrane having an asymmetric structure having a dense layer on one surface by thermally induced phase separation
Implementation Method 2
a polyolefin-based resin is extruded from a spinneret at a temperature equal to or higher than the melting point and thus cooled and solidified
Data Source
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AI summary
A separation membrane including poly(4-methyl-1-pentene) as a main component, a dense layer in at least one surface layer, and a lamellar crystal at an area ratio of 5 to 50% in a surface (1) on a side having the dense layer. According to the present invention, a separation membrane having high solvent resistance and high gas permeability is provided using poly(4-methyl-1-pentene).