Shear-Induced Fragmentation for Polymer Fibre Production
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Solution Overview
Problem
Current methods for producing discontinuous polymer fibres face challenges such as low production rates and difficulties in post-treatment, especially when using template techniques like electrospinning and solution dispersion processes that involve organic solvents and high viscosity dispersants, making it hard to purify and isolate the fibres effectively.
Innovation Solution
A process involving introducing a fibre-forming liquid into a dispersion medium with a viscosity range of 1 to 100 centiPoise, forming a filament, and shearing it to fragment into fibres, allowing for the production of colloidal polymer fibres with controlled dimensions and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If template techniques such as template replication and microfluidics are used to produce discontinuous polymer fibres, then high morphological and dimensional control is achieved, but post-treatment becomes difficult and production rate becomes very low
Solution Approach 1:
The patent replaces complex template-based mechanical systems with a simpler shear-induced fragmentation mechanism. Instead of using microfluidic devices or template replication tools that require precise mechanical control and subsequent difficult post-treatment, the invention uses a viscous non-solvent medium to induce spontaneous filament formation and fragmentation through shear forces, dramatically simplifying the process and enabling high-volume production while maintaining fibre dimensional control
Solution Approach 2:
The patent changes the key parameter from template geometry to shear rate and viscosity ratios. By controlling the shear rate applied to the polymer solution in the viscous non-solvent medium, and by adjusting the viscosity ratio between solution and dispersant, the fibre dimensions are controlled without requiring complex template structures or post-treatment steps, thus achieving both precision and high productivity
2Ease of manufacture
If solution dispersion process uses organic solvents and high viscosity dispersants to form polymer rods, then fibre formation is achieved, but purification and isolation become difficult
Solution Approach 1:
The patent changes the viscosity parameter of the dispersant medium, using viscous non-solvent media with specific viscosity ranges (e.g., 10-1000 cP) that provide sufficient shear for filament formation but allow easy separation. The patent also changes the chemical nature parameter by using non-solvent media that do not require complex purification steps, enabling simple filtration or decantation to isolate the formed fibres
Solution Approach 2:
The patent extracts the harmful organic solvents and high viscosity dispersants from the process by using alternative viscous non-solvent media. These alternative media achieve the same fibre formation function through shear-induced fragmentation but can be easily removed or separated from the final fibre product, eliminating the purification difficulty associated with conventional solution dispersion processes
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
This process enables the production of fibres with controlled dimensions and properties, such as diameters ranging from 15 nm to 5 μm, and lengths up to 3 mm, with narrow polydispersity, and facilitates easier purification and isolation, improving the efficiency and scalability of fibre production.
Implementation Method 1
In forming the gelled filament the fibre-forming liquid may exhibit a gelation rate in the range of from about 1×10−6 m/sec1/2 to 1×10−2 m/sec1/2 in the dispersion medium
Implementation Method 2
The shearing of the gelled filament includes applying a shear stress in the range of from about 100 to about 190,000 cP/sec
Data Source
AI summary
The present invention relates to a process for the preparation of fibers and fibers prepared by the process. The process can provide discontinuous colloidal polymer fibers in a process that employs a low viscosity dispersion medium.