Deformation and fracture behavior of natural fiber reinforced polypropylene

Abstract

Recent works about the mechanical and fracture behavior of natural fiber reinforced polypropylene composites were presented, focusing on the deformation characteristics and the fracture and failure mechanisms exhibited by these materials. The effect of loading conditions and microstructure was analyzed. Test speed and fiber orientation have the same effect observed in synthetic composites. In natural fiber reinforced PP, mechanical fiber degradation may also lead to defibrillation which may counteract the effect of fiber breakage. The great number of influencing factors on the mechanical behavior of fiber reinforced composites is increased when natural fibers are used. Generally, both fiber and matrix modification leads to improved mechanical properties in comparison to unmodified systems. Furthermore, interfacial adhesion can be modified to induce changes in the mode of failure. Introducing an elastomeric component in the coupling agent seems to be the most promising mean of improving fracture properties in these materials, without sacrificing other important mechanical properties. Only a few data of fracture toughness values have been reported in the literature. These values will be needed if these composites are used in structural or semi-structural applications. Finally, natural fiber reinforced polypropylene composites exhibit the same failure mechanisms of their synthetic counterparts. Additional energy absorption mechanisms derived from the presence of natural fibers complicate the failure behavior of these composites.