STUDIES ON THE STRUCTURAL CHARACTERIZATION OF NR VULCANIZATES

The study deals with the estimation of various sulfidic network struct ure and their influence on the strength of the vulcanizates derived fr om 4 ''safe'' binary systems of accelerators containing N-methyl piper azine, namely. (i) MBT and thiuram, (ii) CBS and thiuram, (iii) MBTS a nd thiocarbamyl sulfenamide and (iv) MBTS and dithiodiamines. The stud y reveals that the MBTS-MPTS system can be a safe combination of accel erators for the production of rubber articles. Dithiodiamine in the pr esence of MBTS exhibits the highest activity with regard to strength a s well as number of crosslinkages of the gum vulcanizates, but the rev erse is true for carbon black loaded compounds. A probable reaction me chanism for this has been put forward. From the data regarding the dis tribution of various sulfidic linkages it appears that disulfidic link ages have a significant role in the enhancement of tensile strength of rubber vulcanizates.