Poly(amic acid) synthesis and conversion to high molecular weight polyimide
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Solution Overview
Problem
The synthesis of polyimides often results in the presence of organic solvent residues, which are undesirable in certain applications, and existing methods do not effectively produce polyimides with low organic solvent content.
Innovation Solution
A process involving the reaction of a dianhydride and a diamine in the presence of a higher monoamine in water, under an inert atmosphere, to produce a poly(amic acid) with minimal organic solvent content, which can then be converted to polyimide, either thermally or chemically, without residual solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyimide is synthesized using conventional organic solvent methods, then the synthesis process is efficient and well-established, but organic solvent residues remain in the final product which are undesirable for certain applications
Solution Approach 1:
The patent changes the fundamental parameter of the reaction medium from organic solvent to water. By conducting the polycondensation reaction in an aqueous environment with phase transfer catalysts, the process achieves efficient synthesis while eliminating organic solvent residues from the final polyimide product, directly resolving the contradiction between manufacturing efficiency and product purity
Solution Approach 2:
The patent introduces phase transfer catalysts as intermediary substances that enable the reaction between water-soluble poly(amic acid) and dianhydride to proceed efficiently. These catalysts mediate the interface between the aqueous phase and organic phase, allowing the synthesis to occur without requiring organic solvents, thus maintaining ease of manufacture while eliminating harmful solvent residues
2Object-generated harmful factors
If water is used as the reaction medium for poly(amic acid) synthesis, then organic solvent residues are eliminated, but the reaction efficiency and polymerization control become challenging
Solution Approach 1:
Phase transfer catalysts serve as intermediaries that bridge the aqueous reaction medium and the organic dianhydride reagent. These catalysts enable efficient mass transfer and reaction kinetics in the water-based system, overcoming the inherent inefficiency of using water as a reaction medium while maintaining complete elimination of organic solvent residues
Solution Approach 2:
The patent optimizes reaction parameters including temperature, pH, and catalyst concentration to enhance reaction efficiency in the aqueous medium. By carefully controlling these parameters, the system achieves high productivity and polymerization control without requiring organic solvents, thus resolving the contradiction between using water as medium and maintaining reaction efficiency
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
This method efficiently produces poly(amic acid) and polyimide with no organic solvent residues, offering a cost-effective and environmentally friendly solution suitable for applications where solvent-free products are required.
Implementation Method 1
reacting a dianhydride and a diamine in the presence of a higher monoamine, in water, at a temperature of 60° C. to 180° C., under an inert atmosphere, with agitation, to produce an aqueous poly(amic acid)
Implementation Method 2
The poly(amic acid) is then converted to the polyimide by cyclization, eliminating water
Data Source
AI summary
A process is disclosed for synthesis of a poly(amic acid), including reacting a dianhydride and a diamine in the presence of a tertiary amine, tertiary ammonium salt, tertiary ammonium hydroxide, secondary amine, secondary ammonium salt, secondary ammonium hydroxide, quaternary ammonium salt, quaternary ammonium hydroxide, ammonium hydroxide, or a combination comprising at least one of the foregoing, in water, at a temperature of 60 C to 180 C, or 60 C to 100 C, or 100 C to 180 C, under an inert atmosphere, with agitation, to produce an aqueous poly(amic acid).