EXPERIMENTAL STUDY OF RELAXATION BEHAVIOR OF INJECTED COMPOSITES WITH POLYPROPYLENE REINFORCED BY SHORT FLAX FIBERS

The use of thermoplastic composites reinforced with flax fibers in several fields, particularly in the automotive and aeronautics sectors, provides a favorable response to environmental requirements and new regulations on the recycling composite materials. In this work, we present the experimental study of mechanical behavior, relaxation and morphological evolution of injected polypropylene / short flax fibers, depending on the mold temperature, the fiber content and the nature of coupling agent. This approach is motivated by the existence of relations between the microstructure, the thermal and mechanical parameters of injection molding and the viscoelastic properties of the material that we seek to highlight. The mold temperature and the coupling agent rate have a decisive importance on the morphology and the mechanical properties of the injected composites. Finally, we improve the control of the injection molding process to optimize the visoelastic properties of manufactured parts