Porous Polyimide Nanostructure for Mechanical Strength and Heat Resistance
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Solution Overview
Problem
Existing porous polyimide aerogels and porous carbon sheets face challenges such as poor mechanical strength, low light transmittability, and insufficient heat resistance, which limits their applications in thermal insulation, filter materials, and catalyst carriers.
Innovation Solution
A porous polyimide with a uniform nanostructure and a polyimide wet gel or porous carbon sheet with specific pore size distributions and crosslinked structures are developed, featuring average pore sizes between 1.0 nm and 7.0 nm, high bending elastic modulus, and improved heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyimide aerogels are used, then heat resistance is satisfied, but mechanical strength and toughness are poor
Solution Approach 1:
The patent uses composite materials by combining polyimide with other materials (such as carbon nanotubes, graphene, or ceramic particles) to create aerogels that simultaneously achieve high mechanical strength and heat resistance. The composite structure allows the polyimide matrix to provide heat resistance while the reinforcing materials enhance mechanical properties.
Solution Approach 2:
The patent applies local quality by creating regions with different properties within the aerogel structure. The polyimide matrix provides heat resistance in certain regions, while reinforcing fibers or particles are strategically placed in specific locations to enhance mechanical strength where needed, achieving both properties without compromising either.
2Strength
If porous structure is introduced to reduce density, then heat insulating properties improve, but mechanical strength deteriorates
Solution Approach 1:
The patent employs porous materials by introducing a controlled pore structure into the polyimide aerogel. The porous structure reduces density and improves heat insulation by trapping air pockets, while the polyimide walls between pores maintain mechanical strength. The pore size and distribution are optimized to balance insulation performance with structural integrity.
Solution Approach 2:
The patent uses composite materials to reinforce the porous structure. By incorporating high-strength materials such as carbon nanotubes or aromatic polyamides into the porous polyimide matrix, the aerogel maintains mechanical strength despite the reduced density from porosity. The composite structure allows the porous framework to provide insulation while the reinforcing phase carries mechanical loads.
3Strength
If crosslinked structure is formed to improve mechanical strength, then heat resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the crosslinking degree and type to optimize both mechanical strength and heat resistance. By adjusting crosslinking density, crosslinking agent selection, and curing conditions, the patent achieves a balanced structure where moderate crosslinking provides mechanical strength without creating rigid structures that would deteriorate heat resistance. The crosslinking parameters are tuned to maintain polymer chain mobility necessary for heat dissipation while providing structural reinforcement.
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 developed materials exhibit enhanced toughness, mechanical strength, and heat resistance, making them suitable for a wider range of applications, including thermal insulation and filter materials, while maintaining structural uniformity and transparency.
Implementation Method 1
Aerogels have various characteristics such as low density, high porosity, porousness (mesopore), high specific surface area, high specific strength, high heat insulating properties
Implementation Method 2
Aerogels have various characteristics such as low density, high porosity, porousness (mesopore), high specific surface area, high specific strength, high heat insulating properties, high electrical insulating properties
Data Source
AI summary
The present invention provides a porous polyimide or polyimide wet gel with excellent physical properties. One aspect provides a porous polyimide in which an average pore size (d) obtained by using small-angle x-ray scattering is 1.0 nm to 7.0 nm. One aspect provides a porous polyimide in which the minimum value of the differential coefficient when the logarithmic value log[I(q)] of the scattering intensity I(q) is differentiated by the logarithmic value log[q] of the scattering vector q is −1.0 to 0.0 within a range in which the size of the scattering vector q in small-angle x-ray scattering is 0.025 nm−1 to 0.075 nm−1.