FTIR spectroscopy and swelling studies successfully explained the role of different coagents, namely metallic coagent ZDA, methacrylic coagent (TMPTMA), and allylic coagent (TAC), in the peroxide vulcanization of NR. ZDA and TMPTMA, as Type I coagents increased the delta torque, favoring an addition reaction leading to the homopolymerization and subsequent grafting to the polymer chains.