Styrene-butadiene rubber thermal degradation

Sometimes the term reversion is applied to other types of nonoxidative degradation, especially with respect to rubbers not based on isoprene. For example, thermal aging of SBR (styrene-butadiene rubber), which can cause increased crosslink density and hardening, has been called reversion, since it can be the result of overcure and can also degrade a product s usefulness. 

Radhakrishnan, C., Alex, R., Unnikrishnan, G., Thermal, ozone and gamma ageing of styrene butadiene rubber and poly(ethylene-co-vinyl acetate) blends. Polymer Degradation and Stability 2006,91,902-910. 

Pyrolysis coupled with gas chromatography - mass spectroscopy (Py-GC-MS) in an inert atmosphere has been used to study thermal degradation products of styrene-butadiene rubber (SBR). Introduction of samples, using the pyrolysis carrier... 

The thermal stability of NR and carboxylated styrene butadiene rubber (XSBR) lattices and their blends were studied by thermogravimetric methods by Stephen et The thermal degradation and ageing properties of these individual lattices and their blends were investigated with special reference to blend ratio and vulcanization techniques. As already described, as the XSBR content in the blends increased, their thermal stability was also found to increase. Among sulphur and radiation-vulcanized samples, radiation cured possessed higher thermal stability due to the higher thermal stability of carbon carbon crosslinks. 

Thermal degradation of SBR rubber gives rise to monomers (1,3-butadiene and styrene) as well as to some toluene which turns into carbon dioxide, carbon, monoxide and water, at high temperatures. 

Our laboratory developed ID and 2D spectra-spatial ESRI for the study of het-erophasic systems, such as poly(acrylonitrile-butadiene-styrene) (ABS) and heterophasic propylene-ethylene copolymers (HPEC) containing bis(2,2,6,6-tetram-ethyl-4-piperidinyl) sebacate (Tmuvin 770) as the HAS, and exposed to thermal treatment and UV irradiation.The major objectives were to examine polymer degradation under different conditions to assess the effect of rubber phase (polybutadiene in ABS and ethylene-propylene rubber in HPEC) on the extent of degradation and to evaluate the extent of stabilization by HAS. The repeat units in ABS and the formula of Tinuvin 770 are shown in Fig. 2. 

---