SOLID-STATE C-13 NMR-STUDIES OF VULCANIZED ELASTOMERS .13. TBBS ACCELERATED, SULFUR-VULCANIZATION OF CARBON-BLACK FILLED NATURAL-RUBBER

Solid state C-13 NMR has been used to compare the chemistry of accelerated vulcanization of natural rubber using N-t-butyl-2-benzothiazole sulfenamide in the presence and absence of carbon black. The carbon black filler has an influence on the vulcanization chemistry in addition to its accepted role in reinforcment and stabilization. The basic network structure formation is modified to the extent that crosslink desulfurization from poly to monosulfide structures occurs earlier in the cure in the presence of carbon black. No main chain scission or double bond migration was detected.