Specimens for tensile and tear testing were
punched out from the vulcanized sheets.
Tensile testing was done as per ASTM D412,
using dumb-bell specimens and at a rate of
grip separation of 500 50 mm/min. For the
hardness test, a Shore A type durometer was
employed to find out the hardness of the
vulcanizates. The method adopted is the same
as that of ASTM D 2240 and the readings
were taken after 5 s of indentation. Resilience
was done according to ASTM D 2632 using
a Vertical Rebound. Figure 1, that plot of
stress versus strain. Measures the area undereath the stress-strain curve called toughness.
Toughness is really a measure of the energy a
sample can absorb before specimen breaks.