Processing, thermal and mechanical properties of composite laminates with natural fibers prepregs

This work manufactured prepregs by impregnating discontinuous curaua fibers with B-stage epoxy resin. The prepreg layers were then stacked to produce laminates by hot compression. Alkaline treatments were previously applied to the curaua fibers to improve their interface with the polymer matrix. Then, the prepregs and the final composites were studied regarding their thermal, dynamic mechanical, mechanical, and morphological behavior. The treatments promoted defibrillation by removing lignin and hemicellulose from the fibers, which allowed better impregnation of the treated fibers with epoxy resin. In general, laminates that used treated fibers exhibited the largest storage modulus in the glassy region. The mechanical results showed the laminates produced with treated fibers prepregs presented a highest tensile and flexural resistance than those manufactured with untreated fibers and neat epoxy resin. The NaOH-treated curaua/epoxy laminate exhibited high tensile strength (56.2 MPa) and modulus (3.3 GPa). Overall, fracture morphology indicated better fiber adhesion for the treated fiber composites. The results demonstrate that natural fibers prepregs can be successfully produced and present proper physical and mechanical behavior in components.