Saturday 29 December 2012

Bicomponent Fibers by overjacketing extrusion and electrospinning

Felix A. Reifler of EMPA Laboratory for Advanced Fibers, St. Gallen (Switzerland) was using overjacketing extrusion to add a sheath or sheaths to a monofil core. The technology was essentially that used to apply insulation to fine copper wires.  The main application appears to be applying an insulating sheath to silver-coated yarns for use in conductive textiles.  An 80 micron polyester is plasma-sputter coated with silver and overcoated with 8 microns of thermoplastic PA12-based elastomer at 25 m/min.  Dip-coating can also be used.  PLA and PVA sheaths have also been tried.  Adhesion of the sheath needs improving and the work continues.

Juan Esteban Diaz Gómez of NanoMyP Nanomateriales y Polímeros S.L., Armilla (Spain) has been spinning bicomponent nanofibres from annular nozzles where the core polymer solution can be a non-electrospinnable polymer.  Hollow nanofibres, and liquid filled nanofibres (hydrophobic liquid inside a hydrophilic polymer) are also possible.  They are now working on scaling up the process and further improving it with air-jets (“electroblowing”) or rotation (“Forcespinning™).  “Smart materials with physicochemical properties tailored to customer needs” is now the subject of a new department.  P&G, Unilever and Henkel were among the companies listed as customers of NanoMyP.

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