Composition of SBR
In rubber analysis, the sample is frst heat-
ed to 600 °C under inert conditions. The
volatile components (plasticizers, often
oils) vaporize and pyrolysis of the polymer
begins shortly afterward at about 400 °C.
At 600 °C, the atmosphere is then switched
from inert to oxidative, resulting in the
combustion of the carbon black additive.
Inorganic components remain behind as a
residue. The SBR sample analyzed in the
example contained 6.4% plasticizer, 68.2%
polymer and 21.8% carbon black. The resi-
due (mainly zinc oxide) was 3.6%.