The comparison effects of palm oil fatty acid and stearic acid in various natural rubber compounds

The effect of palm oil fatty acid (POFA) and stearic acid on dynamic properties, curing characteristics and mechanical properties of natural rubber (SMR L) and epoxidized natural rubber (ENR 50) was investigated in the concentration range of 1 to 7 phr. Results indicate that scorch time, t(2), cure time, t(90) and maximum elastic torque increased with increasing both acid concentrations. The incorporation of palm oil fatty acid and stearic acid in both rubbers also resulted in lower damping (lower tan delta ) and lower hysteresis (lower viscous torque). The tensile modulus (modulus at 100% elongation and 300% elongation, M300) and hardness increased with increasing acid concentration whereas tensile and tear strengths increased up to a maximum value and then decreased. At similar acid concentration, stearic acid and palm oil fatty acid in ENR 50 compounds show higher M100, M300 and hardness, but lower tensile and tear strengths than in SMR L compounds.