Recovered carbon black (rCB) is the first sustainable rubber filler available on an industrial scale. It is mainly obtained by pyrolysis of end-of-life tires (ELT) and used in new tire compounds in the sense of circularity. There is a consensus in both the rCB and tire industries that rCB is not carbon black but a new sustainable type of filler. Differences arise from its heterogeneous composition, carbonaceous residues and thermal history. From an analytical point of view, one of the new challenges is to identify rCB in the final tire components. Electron microscopy and molecular spectroscopy are suitable methods for this purpose.

• Key differences between virgin carbon black (vCB) and recovered carbon black (rCB)
• Insights into the microstructure of rubber compounds filled with rCB
• Molecular spectroscopy is an alternative characterization method for recovered carbon black (rCB)