Manufacturing of polymer continuous nanofibers using a novel co-extrusion and multiplication technique

A novel co-extrusion and two-dimensional multiplication technique was developed for continuous production of nanofibers using melt-processable polymers. This solvent-free and environment-friendly fiber fabrication approach has significant advantages over existing solvent-based techniques such as electrospinning. The flexibility of the co-extrusion processing for nanofiber fabrication is demonstrated using three examples. Multicomponent extrudate strands of polycaprolactone (PCL)/polyethylene oxide (PEO), polyamide 6 (PA6)/polyethylene terephthalate (PET) and polyethylene (PE)/polypropylene (PP) were fabricated for nanofiber production. PCL nanofibers were produced by removal of PEO component using water as a solvent. PCL fibers down to 70 nm thickness were successfully produced using this approach. In contrast, a mechanical separation approach was used to produce fibers from PA6/PET and PE/PP systems. Both systems resulted into formation of mixed fibers. A post processing technique was utilized to increase the fiber orientation and mechanical properties. An order of magnitude improvement was observed in mechanical properties after orientation. This novel fabrication approach has enabled solvent-free production of nanofibers at large scale for various applications such as scaffolds, filtration media and others. (C) 2013 Published by Elsevier Ltd.