Study on kinetic of natural rubber vulcanization by using vulcameter

The velocity of vulcameter torque change during the vulcanization of natural rubber consists of two increasing and decreasing stages. The vulcanization process in the stage of velocity increasing is not a simple reaction, and can be expressed in an equation of ln(MH − Mt) = lnA − K1(t − t0)α, which is different from the famous equation of Vut = − (aK3/K4)ln[(K2eK1t − K1eK2t)/(K2 − K1)] deduced by Coran, the value of K11/α in the former can be used as a rate constant to calculate the value of activation energy (E1) according to the Arrhenius equation. The vulcanization process in the stage of velocity decreasing consists of two first‐order reactions, and can be expressed in a kinetic equation of ln(MH − Mt) = lnB − K(t − tdis). The time (tp) at which the torque change reaches to the maximum velocity (Vm) is corresponding to the time (tdis) suggested by Coran.