Development and characterization of polyurethane matrix composites derived from castor oil reinforced with titica vine

ABSTRACT In this work, a natural fiber extracted from “titica” vines ( Heteropsis Flexuosa ) was used, as reinforcement for a biodegradable castor oil derived polyurethane (COPU) matrix. The composites were fabricated with 50, 60 and 70 vol.% of titica vine fibers (TVF). The fibers were characterized by tensile testing and scanning electron microscopy (SEM), and their density was determined as 0.55 g/cm 3 by water pycnometry. Mechanical properties of the composites were evaluated through tensile, flexural, and impact tests, along with dilatometry analysis. The hollow microstructure presented by the TVF corroborates the low density and relatively low tensile strength 39.8 ± 23.8 MPa as well as the high dispersion found in the extraction region within the vine. Despite this, it was found that the fibers acts as reinforcement on the COPU resin whereas the lowest performance composites presented 23.8 ± 4.7 MPa, 100.7 ± 24.5 MPa and 17.6 ± 4.6 J/m an increase, on average, of 119, 200 and 4 times when compared to the neat resin for tensile strength, flexural strength and charpy notch resistance, respectively. Furthermore, dilatometry results indicate that the presence of fibers restricts polymer chain mobility, contributing to the observed increase in stiffness of the composites.