Tensile properties and potential applications of Moringa Oleifera bark-silicone biocomposite

Abstract

Moringa Oleifera plant is known as a Miracle Tree, where its bark contains medicinal properties. In an attempt to embed this superior capability, Moringa Oleifera bark (MOB) fibre was reinforced into a silicone matrix. This study investigated the effect of various MOB fibre content (0wt%, 4wt%, 8wt%, 12wt%, and 16wt%) on the tensile behaviour of silicone biocomposites. Tensile tests were carried out according to ASTM D412 for silicone biocomposites (soft composites). Due to the nature of non-linear, large-deformation behaviour, the silicone-biocomposites were assumed to be hyperelastic and its tensile properties were quantified based on the Neo-Hookean hyperelastic constitutive equation. The results showed that the value of Neo-Hookean material constant, C1, for MOB–Silicone biocomposite increased from 0.036 MPa to 0.059 MPa when fibre content increased to 16wt%. Pure silicone showed the highest elongation, indicating the hyperelastic stretch ratio of 11.07 before fracture. At 16wt%, the stretch ratio restrained to 8.01 before fracture. By computation, the stiffness of 16wt% fibre content for silicone biocomposite has increased by 64% while the stretch ratio is reduced by 27%. Thus, it can be concluded that reinforcing MOB fibre has affected the stiffness more than the elongation of silicone rubber under uniaxial tension. Finally, the quantified properties are compared to other materials for benchmarking purposes and exploring potential applications.