3
The Effect of Binding Free Sulfur in Vulcanized Soybean Oil
ABSTRACT
The effect that different accelerators have on binding the free sulfur in Vulcanized Vegetable Oil (VVO) to improve long term heat aging properties in a NR compound were evaluated. Research on using 1.0 PHR of a thiuram accelerator (TMTD) to bind the free sulfur in VVO to improve heat aging properties has been undertaken in the past by the University of Akron. The purpose of this study is to see if other accelerators or higher loading levels of accelerators can bind the free sulfur within the VVO as well as, or better than 1.0 PHR of TMTD. Five different types of accelerators were reviewed at different levels and 1.0 PHR of a dithiocarbamate (ZDMC), 2.0 PHR of a thiazole (MBTS), and 2.0 PHR of a guanidine (DPG) had the most dramatic effects on aging. Most accelerators evaluated improved their ability to bind free sulfur at higher levels. The addition of some accelerators was able to improve aging properties while maintaining the improved ozone resistance typical to a NR compound containing VVO.