Physico-mechanical properties of elastomers based on natural rubber filled with silica and clay

The elastomers based on natural rubber (NR) and silica and clay fillers have been investigated for its physico-mechanical properties. The various mixes were compounded in a Banbury-Pullen laboratory mill and vulcanized using the efficient vulcanization system. The Oscillating Disc Rheometer (ODR) was used for determination of cure characteristics. It was estimated that replacement of silica with clay up to 30 phr (50% replacement) increased the compound cure rate with a reduction in absolute torque level (Tmax) of the natural rubber mix. Scorch time (Ts2) was observed to be highest at 30/30 filler ratio. Hardness and tensile properties of obtained elastomeric materials were studied. Results show a decrease in parameters as the replacement of silica with natural clay progresses. There was an improvement in elongation at break with increasing the clay content. The replacing of silica filler with clay reduced the abrasion properties (mg. loss/1000 rev.).