Characterisation of static and dynamic responses of natural rubber bio-composites

Abstract

Characterisation of static and dynamic behavioural are presented in this study of hybrid filled natural rubber. The hybrid filler consists of a combination of oil palm ash (OPA) and egg shell powder (ESP). Testing on the samples are conducted in three different aspects namely static compression testing, time dependent stress relaxation testing in compression and dynamic compression testing. Mechanical properties such as the static stiffnesses, hysteresis loss ratios, stress relaxation responses, dynamic stiffnesses, phase angles and damping ratios are reported. The static stiffness values of the hybrid filled rubber, although lower than rubber filled carbon black, presented potential if the ESP content were to be increased. The stress relaxation responses lacked consistency in the uploading stages but were fairly consistent in the unloading stages where the relaxation was close to that of rubber filled carbon black. The dynamic properties appear to be no significant improvement over that of rubber filled carbon black filled. All hybrid filled rubber samples conformed to general dynamic properties of viscoelastic material and did not display any unexpected behaviour. Collectively, there is a trend of improvement with increasing ESP content but no prominent improvement over rubber filled carbon black is observed.