8Carbon black nanoparticles (CB lp ) were derived from waste tire rubbers via a 9 melt-extrusion pyrolysis process at 300 o C. A polymeric shell was observed on the 10 surface of CB lp , which was formed by bound rubber. The chemical structure and 11 content of the bound rubber shell were characterized and quantified, and compared with 12 the commercial carbon black N330 and pyrolytic carbon black (CB p ). The average 13 particle size of CB lp is about 22 nm, with a rubber shell thickness of 7-12 nm. 14 Functional carboxylic group and ZnO were detected on the surface of CB lp by FTIR 15 and XRD, respectively, which are absent from N330 and CB p . The core-shell structure 16 of CB lp facilitate the dispersion and interfacial interaction in natural rubber, and lead to 17 a higher reinforcement effect as compared those of N330 and CB p .