Polyimide Material with Aliphatic Segments for Peel Strength
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Solution Overview
Problem
Polyimide materials currently available do not simultaneously exhibit high peel strength, tear strength, flexibility, and high glass transition temperature, which are required for advanced applications in aerospace, microelectronics, electronics, and automobile fields.
Innovation Solution
A polyimide material comprising repeating units with specific chemical structures and a coupling agent-containing filler, where the intrinsic viscosity of polyamic acid is controlled within a certain range, allowing for improved mechanical properties and imidization to form a non-close-type cross-linked structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyimide structures are used, then good mechanical properties and electrical properties are achieved, but peel strength and tear strength are insufficient
Solution Approach 1:
The patent uses a composite molecular structure combining aromatic rings (for strength and stability) with aliphatic chains (for flexibility and processability). The polyimide contains both rigid aromatic segments and flexible aliphatic segments in its backbone, creating a composite material at the molecular level that simultaneously achieves high strength and good flexibility.
Solution Approach 2:
The patent introduces different functional groups at specific positions in the molecular chain - aromatic rings at key positions for strength, aliphatic chains for flexibility, and hydroxyl groups for hydrogen bonding. This local differentiation of molecular properties allows simultaneous optimization of multiple performance characteristics.
2Strength
If higher rigidity and mechanical strength are achieved through full-aromatic polyimides, then peel strength improves, but flexibility and processability deteriorate
Solution Approach 1:
The patent changes the molecular parameters by introducing aliphatic chain segments with adjustable lengths (controlled by parameters m and n in the formula) into the polyimide backbone. This allows continuous tuning of the balance between rigidity and flexibility, enabling optimization for specific applications while maintaining good processability.
Solution Approach 2:
The patent places flexible aliphatic chain segments locally within the molecular structure rather than making the entire chain aromatic. This local flexibility introduction maintains the rigid aromatic segments needed for strength while adding flexibility where needed, resolving the contradiction between peel strength and flexibility.
3Temperature
If glass transition temperature is increased for high-temperature applications, then heat resistance improves, but molecular mobility and processability decrease
Solution Approach 1:
The patent uses parameter m and n to control the ratio of rigid aromatic segments to flexible aliphatic segments. By adjusting these parameters, the glass transition temperature can be precisely controlled to meet specific application requirements while maintaining adequate processability during manufacturing.
Solution Approach 2:
The aliphatic chain segments act as intermediaries between the rigid aromatic segments, providing molecular mobility that facilitates processing while the aromatic segments maintain high-temperature stability. This intermediary structure allows the material to be processed at moderate temperatures and then perform at high temperatures.
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 polyimide material achieves enhanced peel strength, tear strength, flexibility, and high glass transition temperature, meeting the comprehensive performance requirements for advanced applications.
Implementation Method 1
contacting the polyamic acid with an aliphatic dicarboxylic acid of formula (II) to produce an intermediate... and imidizing the intermediate to produce the polyimide material
Implementation Method 2
A polyimide material comprising repeating units of formula (I)... and a coupling agent-containing filler
Data Source
AI summary
A polyimide material comprises a polyimide. The polyimide has repeating units of formula (I). The polyimide material further comprises a coupling agent-containing filler.A method for preparing a polyimide material comprises allowing a mixture comprising an aromatic tetracarboxylic dianhydride, an aromatic diamine, and a coupling agent-containing filler to react to produce a polyamic acid. The method further comprises contacting the polyamic acid with an aliphatic dicarboxylic acid of formula (II) to produce an intermediate, and imidizing the intermediate to produce the polyimide material.A polyimide comprises repeating units of formula (I).