Regeneration of carbon black from waste automobile tires

Carbon black, an important ingredient in tires, was regenerated from waste automobile tires. Waste tires were cut to separate the tread cap, tread base, side wall, and inner ply and were crushed and pyrolyzed in a muffle furnace at 430°C for 3 h. This black was again heated at 430°C for 1.5 h to increase the surface area to get regenerated black (RB). To find out the effect of heating during pyrolysis, the original black was also heated at 430°C for 1.5 h to get heat-treated black (HTB). The regenerated black (RB) was characterized by different methods. It was mixed in different formulations, with few required properties of the final mixed compounds measured, and then cured maintaining technical cure time and temperature; physicomechanical properties of the cured specimen were measured and compared with that of the virgin black (VB) and the heat-treated black (HTB). From all these results it was concluded that regenerated black has a higher surface area, higher elongation at break, and higher heat buildup but a lower cure rate, a lower modulus, and a comparable state of cure, dispersion, hardness, tensile strength, and tear strength compared with those of the virgin black. It was also found that for the regenerated black, the structure and agglomerate size were slightly changed. Some polar acidic groups were incorporated into the carbon black during pyrolysis or during heat treatment. Regenerated black had better aging properties than did the virgin or heat-treated black. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 465–473, 2003