Expanding the range of auxetic polymeric products using a novel melt‐spinning route

AbstractThe first auxetic fibre was successfully produced in polypropylene using a novel melt‐spinning route. These fibres were extruded at 159 °C with a screw speed 10 rpm (1.05 rad s–1) and 2 mpm (0.03 m s–1) take‐up speed. Characterisation of these fibres involved optical techniques (videoextensometry) to measure the strains along both the length and the width simultaneously during deformation. The unique processing route has now been developed to expand the range of auxetic extruded polymeric products. We report here that auxetic polypropylene films have been developed, and auxetic polyester and polyamide fibres have now been produced. We also report the development of a simple rough particle model to predict auxetic behaviour that may be applicable to the developed fibres and films. Finally, a review of some potential applications for auxetic fibres and films will be presented. These include as reinforcements in composites, anchoring devices, smart bandages for health‐care, breathable packaging and tear resistant films. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)