Effect of surface treatments on the dynamic mechanical behavior of piassava fiber-polyester matrix composites

The effect of several fiber surface treatments upon the dynamic mechanical behavior of piassava fiber-reinforced composites was evaluated. In the light of the experimental results obtained the critical volume fraction for the fibers to effectively perform as reinforcement was established. The results show that all treatments performed (mercerization, acetylation, and mercerization + acetylation) enhance the fiber/matrix adhesion, but some treatments also affect the fiber's integrity. At the elastic region the storage modulus of the composites fabricated with treated fibers was higher than that of the untreated fiber-reinforced composite. However, only the composite manufactured with 10 wt% mercerized fibers showed a statistically significant increase of the storage modulus. Above T-g the storage modulus was primarily governed by the volume fraction of fibers. Therefore, raw and treated fiber composites had essentially the same behavior.