Physical and chemical characterization of representative samples of recycled rubber from end-of-life tires

- A large number of ELTs were sampled and classified by type, age and origin.
- Selected recycled tyre rubber samples were characterized.
- PAH contents were homogeneous and fell within in a narrow range.
- Recent ELT recycled rubber had a reduction H-bay index than older material.
- PAH characterization can be employed to calculate the H-bay index.

A large number of end-of-life tires (ELTs) were sampled and classified by type, age and origin to obtain recycled rubber samples representative of the materials placed on the Italian market. The selected recycled tire rubber samples were physically and chemically characterized and a chemometric approach was used to determine correlations. The polycyclic aromatic hydrocarbons (PAHs) content was correlated to the aromaticity index and a model was built to establish the H-Bay aromaticity index (H-Bay) from the PAH concentrations. ELT of different origin and age produced in non-European countries generally had higher PAH content and a higher H-Bay index. H-Bay values of all the samples were lower than the REACH limits and old tires had higher aromatic content than recent ones, possibly due to the replacement of aromatic oils in tire production.