Kinetics of vulcanization of low-protein natural rubber (LPNR) was studied with the use of a vulcameter. In the induction period of vulcanization, the time t(0) of LPNR is longer than that of natural rubber (NR), and the temperature dependences of the time t(dis) and the rate constant k(1)(1/alpha) of LPNR are greater than that of NR. Both the curing periods of LPNR and NR (except 170 degrees C for LPNR) consist of two stages. The first stage follows first-order reaction. The rate constant k(2) of LPNR in the first stage is substantially the same as that of NR at the same temperature, and so is the activation energy E-2. The second stage (end stage of the curing period) does not follow first-order reaction, and the calculated reaction order n is in the range of 0.67-0.73. Both rate constants of LPNR (except 170 degrees C) and NR at the same temperature are approximately the same, and so is the activation energy E-3. The whole process of curing period for LPNR at 170 degrees C follows n = 0.7 order reaction. (c) 2007 Wiley Periodicals, Inc.