Flexible composite strands through extrusion of crimped fiber reinforced thermoplastic elastomers

Flexible composites made of an elastomeric matrix reinforced with wavy fibers combine the major properties of both materials: the flexibility and high elongation of the elastomer and the strength of the fibers. Wavy fiber reinforced elastomers show a J-shaped stress-strain relationship, starting with a region of low stiffness, followed by a rapid onset and a region of high stiffness. Such mechanical behavior is also known from biological soft tissues like tendons, ligaments and skin, making wavy fiber reinforced elastomers potentially useful in artificial biomaterials. The aim of this study was to investigate thermoplastic extrusion for the manufacturing of wavy fiber reinforced elastomers, which could be produced on a large scale. The resulting composite strands showed a distinct J-shaped stress-strain relationship, with an onset point at 3-12% strain, depending on the manufacturing parameters.