Auxetic polypropylene fibres Part 1 - Manufacture and characterisation

The term 'auxetic' is applied to materials that possess a negative Poisson's ratio nu. The use of auxetic polymers has been limited because of problems with deploying them in their fabricated forms, i.e. as 10 mm diameter cylinders. This paper reports the successful development of a processing route to produce a more useful and usable form of auxetic polymeric material, namely fibres. A conventional polymer processing technique (melt spinning) is the basis of this technique, with novel modifications. Video extensometry was used to measure the Poisson's ratio and a value of nu = -0.60 +/- 0.05 was obtained. (C) 2002 IoM Communications Ltd. Published by Maney for the Institute of Materials, Minerals and Mining.