CONICET | Buscador de Institutos y Recursos Humanos

The best disposal method is under discussion. In the case of plastics there are different available methods: landfills, biodegradation, reuse and recycling. In this work, two different solutions have been presented: reuse and recycling. In the first approach flax fibre/vinylester composite were milled and mixed with virgin matrices to produce composites. The effect of this powder on the mechanical properties of a thermosetting (vinylester: VE) and a thermoplastic (polypropylene: PP) was studied.For VE flexural and tensile strength decreased with the adittion of powder.For filler contents higher than 50%, the strength reached a constant value.Flexural and Young’s modulus was independent on the powder contents. For PP, strength and modulus decreased when powder replaced fibers. Both, fibers and powder acted as reinforcement because modulus increased.Impact properties were improved with the addition of powder and fibers in comparisson to the pure matrix.In the second one, the influence of multiple extrusion cycles on the behavior of 20 wt.% flax fibres / polypropylene composites was studied. Final fibers dimensions (length and diameter) were measured by optical microscopy. Mechanical properties of matrix and composites were measured after each extrusion cycle. The elastic modulus of the matrix was higher after the first cycle than that of the virgin material, mainly due to chain scission. In the next cycles, the modulus kept constant. For composites, the elastic modulus after a single extrusion step was lower than that predicted by the Halpin – Tsai model probably due to a poor mixing and the low fibre/matrix adhesion. In the following two steps, modulus increased because of the better fibre dispersion. For the final two extrusion cycles, the slow decrease in this property was correlated with the darkening and poor organoleptic properties observed as a result of thermal degradation.