3. Results and discussion
3.1. Processing characteristics
The variation in the mixing torque with respect to time during
the preparation of TPVs was recorded from the Haake Rheomix and
shown in Fig. 1. Dynamic vulcanization is evident from the increase
in torque value with the addition of curative (coagent assisted peroxide).
Reversion of the torque values after reaching maximum is
expected due to the combined effect of disintegration of crosslinked
EOC domains and the degradation in the PP phase [20].
The peak torque values obtained for the composition employed
in the study are shown in Table 2. With the addition of 1,2-PB as
coagent, peak torque value increases which suggests the increase
in the extent of crosslinking in the EOC phase. The peak torque value
increases gradually up to 3 phr of and then decreases with the
increase in concentration of 1,2-PB. The possible reason is that, 1,2-
PB eventually undergoes intramolecular cyclization to form a six
member ring system [21] and utilize the free radicals to form coagent
clusters particularly at higher concentrations. The homopolymerization
and/or cyclopolymerization dominates over the
grafting and/or crosslinking reaction with the addition of 1,2-PB
in PP/EOC TPVs especially at higher concentration. Fig. 2 shows