Amidized Polyimide Nanowebs for Hydrolysis-Resistant Filtration
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Solution Overview
Problem
Aromatic polyimide nanowebs are hydrolytically unstable at temperatures above 100°C and require specialized adhesives for substrate adhesion, limiting their compatibility and durability in various applications, such as filtration and battery separators.
Innovation Solution
Surface modification of aromatic polyimide nanowebs by contacting them with a primary amine solution containing a hydrocarbyl radical functional group, which forms a secondary amide, enhancing chemical stability and compatibility while maintaining porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If aromatic polyimide nanowebs are used as filtration media or battery separators, then porosity and thermal stability are improved, but hydrolytic stability deteriorates at temperatures above 100°C
Solution Approach 1:
The patent applies parameter changes by modifying the surface chemistry of the polyimide nanoweb through reaction with primary amines. This chemical modification changes the surface properties to introduce hydrophobic character and improve hydrolytic stability while preserving the bulk thermal stability and porosity of the nanoweb structure
Solution Approach 2:
The patent creates a composite structure by combining polyimide nanofibers with surface-modified amine groups. The resulting material has a core-shell like structure where the polyimide core provides thermal stability and the amine-modified surface layer provides hydrolytic stability and hydrophobicity
2Temperature
If aromatic polyimide nanowebs are used as filtration media, then porosity and thermal stability are improved, but compatibility with substrates deteriorates, requiring specialized adhesives
Solution Approach 1:
The patent modifies surface parameters by introducing amine functional groups that can form secondary amides with carboxylic acid groups on substrates. This chemical modification enables direct bonding between the nanoweb and substrates like epoxies, eliminating the need for specialized adhesives while maintaining thermal stability
Solution Approach 2:
The amine-modified surface acts as an intermediary layer that provides chemical bonding capability between the polyimide nanoweb and substrate materials. The secondary amide bonds formed at the interface serve as a strong chemical bridge, improving adhesion without requiring additional adhesive materials
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 surface-modified nanowebs exhibit improved chemical resistance, hydrophobicity, and reduced swelling, making them suitable for filtration and battery separator applications with enhanced performance and stability.
Implementation Method 1
contacting them with a primary amine solution containing a hydrocarbyl radical functional group, which forms a secondary amide
Implementation Method 2
The surface-modified nanowebs exhibit improved chemical resistance, hydrophobicity, and reduced swelling
Data Source
AI summary
The present invention is directed to the preparation and use of aromatic polyimide nanowebs with amide-modified surfaces. Uses include as a filtration medium, and as a separator in batteries, particularly lithium-ion batteries. The invention is also directed to a filtration apparatus comprising the aromatic polyimide nanoweb with amide-modified surface. The invention is further directed to a multi-layer article comprising the aromatic polyimide nanoweb with amide-modified surface, and to an electrochemical cell comprising the multi-layer article.