Polyimide Synthesis via Water-Soluble Salt Polycondensation
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Solution Overview
Problem
The high energy and equipment expenditure required to generate hydrothermal conditions for using water as a solvent in polyimide synthesis is a significant disadvantage, despite recent advancements allowing for crystalline polyimide production under these conditions.
Innovation Solution
A process involving the preparation of water-soluble stoichiometric salts of polycarboxylic acids or their polyanhydrides, which are then subjected to a processing step and subsequently heated to undergo polycondensation, allowing for direct conversion to polyimides without the need for expensive solvent removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If water is used as a solvent under hydrothermal conditions for polyimide synthesis, then crystalline polyimides can be produced, but high energy and equipment expenditure is required to generate hydrothermal conditions
Solution Approach 1:
The invention changes the physical-chemical parameters of the reaction system by using water-soluble monomer salts instead of requiring hydrothermal conditions. The salts dissolve in water at ambient temperature, enabling the reaction to proceed without high temperature and pressure, thus resolving the contradiction between producing crystalline polyimides and reducing energy consumption
Solution Approach 2:
The invention employs water as a disposable, inexpensive solvent that can be easily removed without requiring energy-intensive equipment. The water-soluble monomer salts enable the use of water as solvent, and after the reaction, water can be simply evaporated or dried away, eliminating the need for complex solvent removal systems required by traditional organic solvents
2Ease of manufacture
If water is used as a solvent for polyimide synthesis, then solvent removal is simplified, but high energy expenditure is required for solvent removal in conventional processes
Solution Approach 1:
Water is used as a disposable solvent that can be easily removed by simple evaporation or drying processes. Unlike organic solvents that require complex distillation equipment and high energy input, water can be removed using low-energy methods such as ambient drying or low-temperature evaporation, thus achieving both ease of manufacture and low energy consumption
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 reduces the energy and equipment costs associated with polyimide production by enabling the use of water as a solvent while achieving crystalline polyimides, and allows for the production of polyimide coatings, foams, and molded products with improved handling and properties.
Implementation Method 1
polycondensation of previously prepared stoichiometric salts of polycarboxylic acids or their polyanhydrides and polyamines by heating the salts for dehydration
Implementation Method 2
heating the salts for dehydration
Implementation Method 3
heating—preferably to a temperature Tp above the solid-phase polymerization temperature of the salt to ensure complete conversion of the polycondensation reaction
Data Source
AI summary
The invention relates to a method for producing polyimides by the polycondensation of previously produced stoichiometric salts from polycarboxylic acids or their polyanhydrides and polyamines, by heating the salts for dehydration, the method being characterised in that: a) an aqueous solution of a water-soluble stoichiometric salt is produced from polycarboxylic acid and polyamine; b) the aqueous solution undergoes a processing step; and c) the salt contained in the solution is simultaneously or subsequently polycondensed, by means of heating, to form a polyimide.