Mooney scorch time of epoxidized natural rubber
Article first published online: 10 MAR 2003
Copyright © 1991 John Wiley & Sons, Inc.
Journal of Applied Polymer Science
Volume 42, Issue 5, pages 1407–1416, 5 March 1991
How to Cite
Poh, B. T. and Tan, B. K. (1991), Mooney scorch time of epoxidized natural rubber. J. Appl. Polym. Sci., 42: 1407–1416. doi: 10.1002/app.1991.070420525
- Issue published online: 10 MAR 2003
- Article first published online: 10 MAR 2003
- Manuscript Accepted: 11 MAY 1990
- Manuscript Received: 28 FEB 1990
The scorch property of accelerated sulfur vulcanization of three grades of expoxidized natural rubber (viz. ENR 10, ENR 25, and ENR 50) was studied by using Mooney Shearing Disk Viscometer in the temperature range of 100–180°C. Effects of accelerator types, concentration of accelerator, and carbon black on ENR 10 were also determined. Results obtained indicate a similar scorch behavior as that reported earlier for SMR L. However, some differences in the magnitude of scorch times in the temperature and concentration studies are observed between ENR and SMR L. These differences are attributed to the activation of a double bond by the adjacent epoxide group in ENR, the effect being more significant for a higher degree of epoxidation of natural rubber. In the case of ENR 50, differential scanning calorimetry measurement suggests that additional crosslink occurs via a ring-opening reaction at about 155°C. Based on first-order reaction kinetics, the apparent activation energy of vulcanization for the rubbers studied is estimated and discussed.