Abstract:
The present study aims to investigate the industrial feasibility of using embira fiber, derived from the inner bark of the Embira-branca (Daphnopsis utilis) tree from the Atlantic Forest, as reinforcement in polymer matrix composites made of polyurethane resin (PU) derived from castor oil. Therefore, composites reinforced with 50%, 60%, 70%, 80%, and 90% mass fractions of embira were manufactured and subjected to three-point bending tests. The results show that even with increasing embira mass fractions, the specific flexural strength of the composites remained constant. However, the specific modulus of elasticity in flexure for the composites with 50% reinforcement reached 7.65 MPa.cm³/g, the highest average value, classified as group (a). In contrast, those with 60% and 70% reinforcement, showing no statistically significant differences in their means, were classified as group (b) and had the lowest average, only about 30% of the stiffness of composite (a). Composites reinforced with 70%, 80%, and 90%, classified as group (c), also showed no statistically significant differences in their means, with about 43% of the stiffness of group (a), with the 70% reinforcement fraction common to both groups (b) and (c).