The fatigue behaviour of white rice husk ash (WRHA) filled ENR-50 compounds was compared with those of silica (Vulcasil-S) and carbon black (N 330) filled compounds. The effect of WRHA loading on scorch time and Mooney viscosity was also studied. The incorporation of WRHA in ENR-50 compounds reduced the scorch time but increased the Mooney viscosity. The increment in filler loadings has resulted in the reduction of the fatigue life. The fatigue behaviour of ENR-50 vulcanizates was observed to be strain dependent. At a similar filler loading, silica filled vulcanizates showed the highest fatigue life followed by those of WRHA and carbon black.

The paper reports on the fatigue behaviour of white rice husk ash (WRHA), silica and carbon black-filled ENR 50 vulcanizates. The properties investigated include the stressstrain behaviour, effect of coupling agent and hysteresis. Carbon black filled vulcanizates showed the highest stress-strain behaviour followed by silica and WRHA. This observation was supported by the plot of accumulated strain energy versus extension ratio. Carbon black showed the highest value followed by silica and WRHA. The incorporation of silane coupling agent has improved the fatigue life of WRH-filled vulcanizates. Hysteresis studies showed that as the filler loading increased there was an increase in hysteresis and carbon black filled vulcanizate exhibited the highest hysteresis i.e. the most sensitive towards changes in strain energy.