The scorch time of the curing process was acquired from t5 value ofthe rheograms and depicted in Fig. 3
as a function of cure temperature for the entire vulcanizates.Inaddition, Fig.
3 shows the cure time, calculated from the subtraction of t90 and t10 values, versus cure temperature for EPDM systems containing either nZnO or cZnO ingredients.
At a given activator content, an increase in curing temperature drives the cure process forward by decreasing both the scorch and cure times as expected. Such observation has been already reported by other authors and on the majority of cases has been explained with the availability of more thermal energy and lower viscosity of the compounds upon rising the cure temperature, leading to the facilitated crosslinking and network formation [10–12].
Moreover, the addition of nZnO nanoparticles instead of cZnO in the recipes seems to accelerate the cure reaction of EDPM system; since the scorch and cure times of nZnO-activated samples are lower than those of cZnO-activated ones.
This finding runs in harmony with results reported by other authors