The mechanical properties of natural fibers are influenced by the composition, structure and number of defects in a fiber. Under stress, tensile failure occurs by intercellular and/or intracellular modes. In fibers having higher cellulose content such as those in bananas and pineapples, cracks propagate through weak bonding between cells, causing intercellular fracture without the removal of microfibrils [25]. By contrast, cracks propagate through the cells in fibers with lower cellulose content such as coir,resulting in intracellular fracture with microfibrillar pullout [8,25]. Elongation of fibers depends on the degree of crystallinity, orientation and the angle of
the microfibrils to the fiber axis. The high extensibility of coir fibers is primarily a result of the perfect helical spirals formed by the microfibrils around the fiber axis