2.8. Measurement of crosslink density
Swelling tests on the rubber vulcanisates were performed
in toluene in accordance with ISO 1817. The cured
test pieces (30 mm  5 mm 2 mm) were weighed using
an electrical balance and swollen in toluene until equilibrium,
which took 72 h at room temperature. The samples
were taken out of the liquid, the toluenewas removed from
the sample surfaces and the weight was determined. The
samples were then dried in the oven at 60 C until constant
weight was obtained. The swelling results were used to