2.3. Testing of rubber vulcanizates
Determination of the crosslink density was
carried out by immersing the test specimens in
toluene for 72 h at room temperature (23 1C). After
immersion, the specimens were blotted with filter
paper prior to the determination of mass change.
The swelling ratio was then calculated. The dynamic
properties, i.e., storage modulus (E0), and damping
factor (tan d), were investigated using a dynamic
mechanical analyzer (DMA, Gabo Eplexor 25N).
The test was carried out under tension mode at a
frequency of 10 Hz. The test temperature was varied
from 90 to 25 1C. The tensile properties and tear
strength were determined using a universal testing
machine (Instron 5539 series) following ISO 37 and
34, respectively. The hardness was measured using a
Wallace Shore A durometer according to ISO 7619
Part 1. The rebound resilience was determined using
a Dunlop tripsometer (Toyoseiki 221).