Short kevlar fiber–thermoplastic polyurethane composite

Mechanical and dynamic mechanical behavior of short Kevlar fiber‐filled thermoplastic polyurethane (TPU) have been studied with respect to fiber loading and orientation. The strength of the composite is improved at higher fiber content with a minimum at 10 phr of fibers. Storage and loss moduli (E′, E″) are increased and tan δmax is reduced progressively with fiber loading, the effect on moduli being more pronounced at post‐Tg temperatures. Anisotropy in strength is evident beyond 15 phr fiber loading. Impact strength is reduced considerably at all fiber loading irrespective of fiber orientation. Study of the fracture furface by scanning electron microscopy (SEM) shows good correlation between the modes of failure and strength of the composites. SEM study of the extracted fibers shows the existence of a kinking stage through which the fiber undergoes severe breakage during processing.