Solvent-Soluble Polyimide Copolymer Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polyimide films are solvent-insoluble and have poor storage stability, making them difficult to modify and use in various applications due to their low solubility and rapid decomposition in water.
Innovation Solution
A novel three-step polycondensation process is developed to synthesize solvent-soluble four-component polyimides using specific imide oligomer intermediates and a catalyst system based on lactone equilibrium, allowing for the production of high-purity polyimide copolymers with improved thermal stability and solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polyimide films are used, then high heat resistance is achieved, but solvent solubility is poor
Solution Approach 1:
The patent creates a four-component copolymer system combining PMDA, BPDA, DADE, and DAT in specific ratios. This composite polymer structure integrates the high heat resistance of PMDA-DADE segments with the enhanced solubility characteristics of BPDA-DAT segments, achieving both thermal stability and processability in common solvents like chloroform and dimethylformamide
Solution Approach 2:
The invention introduces local structural variation through the four-component copolymer architecture where different monomer units provide different functional properties. The BPDA-DAT segments contribute to solvent interaction and solubility, while PMDA-DADE segments maintain the core heat resistance, creating localized functional zones within the polymer chain
2Ease of manufacture
If polyamic acid is used as intermediate, then polyimide film can be formed, but storage stability is poor due to water decomposition
Solution Approach 1:
The patent performs the imidization reaction in advance during the polymerization process itself, converting the polyamic acid intermediate directly to the polyimide structure before film formation. This preliminary conversion eliminates the unstable polyamic acid from the final product, preventing water-induced decomposition during storage while maintaining film-forming capabilities
Solution Approach 2:
The invention converts the potentially harmful polyamic acid intermediate, which is prone to water decomposition, into the beneficial polyimide structure through acid-catalyzed imidization. The harmful instability of the intermediate is transformed into a processing advantage, allowing direct conversion to the stable final product
3Productivity
If acid catalyst is used for polycondensation, then polyimide can be synthesized, but catalyst must be separated to prevent deterioration
Solution Approach 1:
The patent introduces water as an intermediary carrier for the acid catalyst. The catalyst is dissolved in water, which acts as a temporary medium during the polycondensation reaction. After completion, the water-based catalyst solution is easily separated from the organic polymer product through phase separation or evaporation, eliminating the need for complex catalyst removal procedures while maintaining high 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
The process results in polyimides with thermal decomposition onset temperatures of 500°C or more and no observed glass transition temperature up to 430°C, enabling their use in diverse applications such as high-heat electronic components, medical materials, and construction materials with enhanced storage stability.
Implementation Method 1
A polyimide film serving as a highly heat-resistant resin was first manufactured in 1960 by DuPont and called KAPTON, which consists of pyromellitic dianhydride (PMDA) and 1,4-diaminodiphenyl ether (DADE).
Implementation Method 2
Polyamic acids readily decompose in water so that they are poor storage stability.
Data Source
AI summary
Heat-resistant polyimide copolymers having the following four components: pyromellitic dianhydride (PMDA), 1,4-diaminodiphenyl ether (DADE), biphenyltetracarboxylic dianhydride (BPDA), and 2,4-diaminotoluene (DAT) are provided. In an embodiment the molar ratio of (BPDA):(DADE):(PMDA):(DAT) is 2:2:m:m, in which m is an integer of 3, 4 or 5.