Novel Diamine Compound for Transparent Polyimide Film
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Solution Overview
Problem
Aromatic polyimides used in high-tech industries face challenges due to strong coloration from intramolecular charge transfer complexes, limiting their application in optoelectronics where transparency and colorlessness are required, and they also suffer from thermal decomposition during high-temperature processing of flexible devices.
Innovation Solution
A novel diamine compound with a specific structure is developed, which, when used as a polymerization component, imparts improved thermal and mechanical properties to the polyimide film, reducing coloration and enhancing stability against thermal decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If aromatic polyimide is used for high-temperature processing, then heat resistance is improved, but thermal decomposition by hydrolysis occurs during high-temperature process
Solution Approach 1:
The patent modifies the chemical structure of the diamine component by introducing specific substituents (fluoro, alkoxy, alkyl groups) at controlled positions to alter the polymer's chemical resistance and storage stability while maintaining heat resistance. This changes the molecular parameters to achieve both high-temperature processing capability and resistance to hydrolytic decomposition.
Solution Approach 2:
The patent creates a composite polyimide structure by combining aromatic dianhydride with specially designed diamine compounds containing multiple functional groups. This composite molecular structure integrates the heat resistance of aromatic polyimide with enhanced chemical stability from the engineered diamine component, preventing thermal decomposition by hydrolysis.
2Strength
If aromatic polyimide is used, then mechanical strength is improved, but strong coloration occurs from intramolecular charge transfer complexes
Solution Approach 1:
The patent introduces specific local substituents (fluoro, alkoxy, alkyl groups) at defined positions on the diamine molecular structure. These localized chemical modifications alter the electron distribution and reduce intramolecular charge transfer, thereby reducing coloration while preserving the overall mechanical strength provided by the aromatic polyimide backbone.
Solution Approach 2:
The patent changes the chemical parameters of the diamine component by introducing electron-donating and electron-withdrawing groups at specific positions. This modifies the HOMO-LUMO energy gap and reduces charge transfer complex formation, resulting in transparent or lightly colored films while maintaining mechanical integrity.
Data Source
AI summary
Disclosed is a novel diamine compound in which an imide ring is directly bonded to a (hetero)aryl ring in a molecule, and a polyimide film prepared by polymerizing the novel diamine compound exhibits improved thermal properties and storage stability.