Nanofiber Production via Solvent Diffusion Extrusion
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Solution Overview
Problem
Current nanofiber production methods, such as electrospinning, are hazardous due to high voltage requirements and often produce nonwoven fabrics, while melt nano dispersion spinning necessitates preliminary melting and fiber drawing, which are cumbersome processes.
Innovation Solution
A solvent diffusion method is developed to produce nanofibers at normal temperature without drawing, involving an organic solvent solution of an oil-soluble diblock copolymer with blocks from aliphatic polyester resin and hydrophilic polymer being extruded into an aqueous surfactant solution, allowing solvent diffusion and fiber formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrospinning method is used to produce nanofibers, then nanofibers can be produced easily, but high voltage is required which creates safety hazards
Solution Approach 1:
The patent replaces the electrostatic field-based electrospinning method with a mechanical extrusion system. The nanofiber-forming solution is extruded through a nozzle under mechanical pressure into a coagulation bath, where fibers form through phase separation rather than electrostatic forces, eliminating the need for high voltage equipment
Solution Approach 2:
The invention uses hydraulic or pneumatic pressure to extrude the nanofiber-forming solution through the nozzle. The pressurized fluid flow controls the extrusion rate and fiber formation process, replacing the electrical field with a fluid dynamic system that is inherently safer
2Productivity
If melt nano dispersion spinning method is used to produce nanofibers, then nanofibers can be produced, but preliminary melting and fiber drawing are required which are cumbersome processes
Solution Approach 1:
The patent performs preliminary dissolution of the polymer in a solvent to create a nanofiber-forming solution before extrusion. This pre-preparation step allows the polymer to be in the optimal state for fiber formation during extrusion, eliminating the need for subsequent melting and drawing operations
Solution Approach 2:
The invention extracts the polymer from its solid state and dissolves it in a solvent to create a processable solution. This extraction into solution phase allows direct extrusion and fiber formation without requiring melting and drawing steps that would be necessary for solid or molten polymer processing
3Productivity
If conventional fiber production methods are used, then fibers can be produced, but fiber width control is limited and drawing operations are required
Solution Approach 1:
The patent controls fiber width by adjusting extrusion parameters including extrusion rate, nozzle diameter, and coagulation bath conditions. These parameter changes directly control the phase separation process and fiber morphology, enabling precise fiber width control without drawing operations that could damage fibers
Solution Approach 2:
The invention uses dynamic control of the extrusion process, where the extrusion rate can be adjusted in real-time to control fiber diameter. The continuous phase separation process allows dynamic adjustment of fiber properties during production, providing flexibility and precision not available in static conventional methods
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 method enables efficient production of nanofibers with controlled diameters, avoiding high voltage and drawing operations, and can produce nanofibers in spun filament form, offering improved productivity and flexibility in fiber width control.
Implementation Method 1
an organic solvent solution of an oil-soluble diblock copolymer with blocks from aliphatic polyester resin and hydrophilic polymer being extruded into an aqueous surfactant solution, allowing solvent diffusion and fiber formation
Data Source
AI summary
The invention provides a method for producing nanofibers of an aliphatic polyester resin (a biodegradable resin) with higher productivity than heretofore achieved, for example, without the need of cumbersome steps such as drawing and with operability at normal temperature. The method for producing nanofibers according to the invention includes (1) an extrusion step of extruding an organic solvent solution (S) into filaments in an aqueous solution (W) including a surfactant (SF) and water, the organic solvent solution (S) including an aliphatic polyester resin (A0) or an oil-soluble low block copolymer (A) including a block derived from an aliphatic polyester resin (A1) and a block derived from a hydrophilic polymer (A2), and an organic solvent (S1); and (2) a spinning step of collecting the filaments of the organic solvent solution (S) extruded in the step (1) while simultaneously diffusing or extracting the organic solvent (S1) of the organic solvent solution (S) into the aqueous solution (W), thereby forming fibers including the aliphatic polyester resin (A0) or the oil-soluble low block copolymer (A).