Porous Polyimide Powders via Precipitation for Rapid Dissolution
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Solution Overview
Problem
Current methods for producing polyimide powders, such as cryo-grinding and jet milling, result in slow dissolution in solvents and polymers like epoxy, leading to high conversion costs, dust inhalation hazards, and material handling difficulties, while also extending cycle times and increasing costs.
Innovation Solution
The development of a method involving precipitation processes without surfactants to produce porous polyimide particles, where a polyimide solution is mixed with water at high shear rates or injected into a steam atmosphere, allowing for the removal of solvents and resulting in fluffy, porous powders with high surface area and rapid dissolution in epoxy matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If polyimide powders are produced by cryo-grinding or jet milling to achieve fine particle size, then dissolution rate in solvents and polymers is improved, but conversion costs increase and dust inhalation hazards arise
Solution Approach 1:
The patent applies the porous materials principle by producing polyimide powders with a porous internal structure through precipitation processes. The porous structure provides high surface area and rapid dissolution without requiring ultra-fine particle sizes. The pores allow solvent penetration throughout the particle interior, achieving fast dissolution rates while maintaining larger, safer particle dimensions that reduce dust hazards and manufacturing costs.
2Speed
If polyimide powders are ground to less than 100 microns or preferably less than 45 microns to improve dissolution, then dissolution rate is improved, but dust inhalation hazards and explosion risks increase
Solution Approach 1:
The patent uses the porous materials principle to create particles with internal porosity rather than relying on external surface area reduction alone. The porous structure allows rapid solvent penetration and dissolution while maintaining larger particle sizes that are safer to handle. The pores provide internal surface area for dissolution without creating the fine dust particles that pose inhalation and explosion hazards.
3Ease of manufacture
If conventional precipitation methods are used without porosity enhancement, then manufacturing is simpler, but dissolution rate in epoxy matrices remains slow
Solution Approach 1:
The patent applies the porous materials principle by modifying the precipitation process to create porous particles. The porous structure is formed during precipitation by controlling solvent removal and phase separation, creating an internal network of pores that dramatically accelerates dissolution rates in epoxy matrices while maintaining manufacturing simplicity. The porosity provides rapid solvent access to the polymer interior without complex additional processing steps.
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 porous polyimide powders exhibit rapid dissolution in solvents and polymers, reducing cycle times, eliminating the need for specialized handling, and providing cost savings by avoiding dust inhalation hazards and high conversion costs.
Implementation Method 1
mixing a solution with water at a high shear rate to form an emulsion
Implementation Method 2
mixing a solution with water at a high shear rate to form an emulsion
Implementation Method 3
The solvent can be removed by heating the solution and the resulting powder can be isolated and dried
Implementation Method 4
injecting a solution into a flowing steam atmosphere
Implementation Method 5
injecting a solution into a flowing steam atmosphere, wherein the solution comprises polyimide and an organic solvent
Data Source
AI summary
Polyetherimide particles or powders with a high surface area and high porosity can be prepared by precipitation of polymer solution in hot water or steam without the use of any additives. The particles or powders produced rapidly dissolved in organic solvents as well as epoxy matrices.