Study on vulcanization kinetics of constant viscosity natural rubber by using a rheometer MDR2000

Vulcanization kinetics of constant viscosity natural rubber (CVNR) prepared with hydroxylamine hydrochloride was studied by using a Rheometer MDR2000. The results show that the first stage of curing period follows first-order reaction, but the induction period and the end stage of curing period does not. The calculated reaction order n of the end stage of curing period of CVNR is in the range of 0.01–0.52, and that of natural rubber (NR) is in the range of 0.38–0.66. The reaction orders of the end stages of curing periods of CVNR and NR increase with increasing curing temperature, and the reaction order of the end stage of curing period of CVNR is smaller than that of NR at the same temperature. The rate constants of the induction period, the first stage of curing period and the end stage of curing period of CVNR are smaller than that of NR at the same temperature. The activation energies of the induction period, the first stage of curing period and the end stage of curing period of CVNR are greater than that of NR. The activation energy of the induction period of CVNR is increased by13.52%, the activation energy of the first stage curing period of CVNR is increased by 3.95%, and the activation energy of the end stage of curing period of CVNR is increased by 1.60% compared with the activation energies of NR. The time tdis of CVNR is longer than that of NR at the same temperature. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013