4. Conclusions
The results show that modulus, hardness and tear
strength of NR filled with conventional fillers and clay are
superior to those of the gum. Hardness and modulus
increase noticeably when 6 phr of clay is added. At equal
loading of fillers, clay-filled NR vulcanizate exhibits higher
modulus, hardness, tensile strength compression set but
lower heat build-up resistance and crack growth resistance
than those of NR vulcanizates containing conventional
fillers. However, their tear strength is not much different.
Compared to CB, a higher amount of silica is needed to
achieve the same hardness as that of the clay-filled sample