Microporous Polyimides via Contorted Dianhydrides
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Solution Overview
Problem
Commercially available polyimides exhibit poor processability due to high melting temperatures and limited solubility in organic solvents, restricting their practical usage, and the synthesis of microporous polyimides is challenging due to limitations in suitable monomers, particularly dianhydrides.
Innovation Solution
A method for synthesizing highly rigid, short dianhydrides with a site of contortion, such as spirobisindane- and ethanoanthracene-based dianhydrides, from biscatechol precursors, which enhances the synthesis of microporous polyimides, improving their solubility, thermal stability, and microporosity, and allows for the production of novel linear and network polyimides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polyimides are used, then thermal stability is achieved, but processability deteriorates due to high melting temperature and limited solubility
Solution Approach 1:
The patent introduces microporous polyimides with intrinsic microporosity created by contortion sites in the polymer backbone. These porous structures provide channels for solvent penetration and polymer chain mobility, significantly improving solubility and processability while maintaining the thermal stability provided by the polyimide backbone structure.
Solution Approach 2:
The patent employs composite monomer structures combining rigid aromatic dianhydrides with diamines containing contortion sites (such as spirobiphenyl, tetraphenylethane, or troger's base units). This composite approach integrates the thermal stability of conventional polyimides with the enhanced processability provided by the contortion-containing moieties.
2Ease of manufacture
If microporous polyimides are synthesized, then processability is improved, but synthesis difficulty increases due to limitations in suitable monomers
Solution Approach 1:
The patent systematically varies the structural parameters of the dianhydride monomers, introducing different contortion sites (spirobiphenyl, tetraphenylethane, troger's base) and adjusting the substitution patterns on the aromatic rings. This parameter variation enables access to multiple microporous polyimide structures with tailored properties while using established condensation polymerization methods.
Solution Approach 2:
The patent develops a universal synthesis approach using condensation polymerization that can accommodate multiple types of dianhydride monomers containing contortion sites. The same general methodology applies whether using spirobiphenyl-based, tetraphenylethane-based, or other contortion-containing dianhydrides, simplifying the synthesis process despite the diversity of specific monomers.
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 synthesized dianhydrides and polyimides exhibit intrinsic microporosity, good thermal stability, and enhanced solubility, enabling their application in various industrial fields, including aerospace, electronics, and gas separation membranes.
Implementation Method 1
Microporous polyimides, formed by condensation of the dianhydrides and diamines containing site of contortion
Data Source
AI summary
The present disclosure provides for a multi-anhydride, a polyimide, a method of making a dianhydride, a method making a multi-anhydride, a method of making a polyimide, and the like.