Low Melt Viscosity Imide Oligomers for RTM Processing
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Solution Overview
Problem
Current polyimides used in composite fabrication processes, such as RTM and RI, face challenges in achieving high glass transition temperatures, mechanical performance, thermo-oxidative stability, and processability, particularly requiring high cure temperatures and exhibiting high melt viscosities, which limits their use in complex shape fabrication and increases costs.
Innovation Solution
The development of novel polyimide oligomers comprising 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 2-(3,4-dicarboxy phenyl)-1-phenylacetylene anhydride, and a mixture of 1,3-diaminobenzene and 4,4′-(1,3-phenylenediisopropylidene) bisaniline, which exhibit low melt viscosity and can be fully cured at lower temperatures, enhancing their suitability for RTM and RI processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional aromatic polyimides are used to achieve high glass transition temperature and thermo-oxidative stability, then thermal performance is improved, but melt viscosity remains high which limits processability in RTM and RI
Solution Approach 1:
The patent changes the molecular weight parameter of the polyimide by using oligomeric polyimides with controlled low molecular weights (specifically designed oligomer structures) instead of high molecular weight polymers. This parameter change reduces melt viscosity while maintaining the high glass transition temperature and thermo-oxidative stability characteristics of aromatic polyimides, enabling processability in RTM and RI applications.
2Strength
If high cure temperatures are used to achieve complete curing and mechanical performance, then material properties are improved, but energy consumption increases and complex shape fabrication becomes more difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the oligomeric polyimide system by incorporating specific aromatic dianhydrides, aromatic diamines, and terminal functional groups (such as carboxylic acid, hydroxyl, or isocyanate groups) that enable complete curing at lower temperatures. This composition optimization allows achieving complete curing and excellent mechanical properties at reduced cure temperatures compared to traditional polyimide systems.
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
These oligomers demonstrate improved toughness, mechanical performance, thermo-oxidative stability, and lower cure temperatures, enabling the fabrication of composite materials with higher glass transition temperatures and reduced costs, while maintaining excellent processing characteristics suitable for complex shape fabrication.
Implementation Method 1
polyimide oligomers comprising 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 2-(3,4-dicarboxy phenyl)-1-phenylacetylene anhydride, and a mixture of 1,3-diaminobenzene and 4,4′-(1,3-phenylenediisopropylidene) bisaniline
Implementation Method 2
The molten resin permeates through the woven preform to completely wet out the preform
Implementation Method 3
During this step, external hydrostatic pressure is often applied to the mold to ensure consolidation
Implementation Method 4
these materials exhibit significantly lower melt viscosities
Data Source
AI summary
The present invention relates to novel imide oligomer compositions, polyimides formed therefrom, and methods for making and using the same. In particular, the invention relates to novel polyimide oligomers comprising 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), 2-(3,4-dicarboxy phenyl)-1-phenylacetylene anhydride (PE), and a mixture of 1,3-diaminobenzene and 4,4′-(1,3-phenylenediisopropylidene) bisaniline. The polyimide oligomers demonstrate low melt viscosity (these resins are melt processable) while retaining exceptional thermo-oxidative stability, high glass transition temperature, and good mechanical properties in the cured state.