DEGRADATION OF HYDROGENATED STYRENE-BUTADIENE RUBBER AT HIGH-TEMPERATURE

Degradation of hydrogenated styrene-butadiene rubber (HSBR) having dif ferent levels of unsaturation has been studied over a wide range of te mperatures under anaerobic and aerobic conditions using thermogravimet ric analysis (TGA), differential scanning calorimetry (DSC), IR and NM R spectroscopy. TGA data indicate higher thermal stability of hydrogen ated rubber as compared to SBR in nitrogen, although an anomalous beha vior is observed in air due to crosslinking and oxidation of styrene-b utadiene rubber (SBR). Isothermal data confirm the above observations. IR and NMR results reveal thermal isomerization, cyclization, oxidati on, depolymerization, and chain scission processes. The nature and amo unt of products formed depend on the time and temperature of degradati on and also on the level of hydrogenation of SBR.