In general, rubber is vulcanized with sulfuric agents for
durability. Analyzing the chemical states of sulfur found in rubber
(monosulfide, disulfide, or polysulfide bond) is typically difficult.
X-ray absorption near-edge structure (XANES) has been used to
determine the chemical states of elements [4,5]. Recently, XANES
analysis for sulfur chemical states was reported [6–12], as well as
for sulfur included in the rubber [13,14]. The sulfur chemical states
change when tire rubber degrades over time or usage. As a result,
variability exists among the sulfur chemical states included in each
tire because the chemical state changes from the time of purchase
to the time of disposal depending on the environment the tire has
been exposed to or the history of usage. Therefore, the tire rubber
may be discriminated based on the chemical states of sulfur.