Evaluation of Pyrolytic Oil from Scrap Tires as Plasticizer of Rubber Compounds

Abstract

A heavy fraction of oil obtained from pyrolysis of rubber crumb derived from scrap tires was studied by H-NMR and FT-IR spectroscopy in comparison to a distillate aromatic extract (DAE) derived from petroleum and currently used as plasticizer in rubber mixes. The spectral data suggest a rough chemical analogy between the two oils although the viscosity and the density of the pyrolysis oil are significantly lower that that of the aromatic extract suggesting a significantly lower average molecular weight for the pyrolytic oil in comparison to the reference DAE oil.

The two oils were tested at 10 and 15 phr level in a NR-based formulation and the cure kinetics and the mechanical properties of the rubber compounds have been measured. The pyrolytic oil gives accelerated cure kinetics, reduced scorch safety and lower compound viscosity in comparison to reference compounds with DAE oil. The mechanical properties of the cured compounds prepared with pyrolysis oil from scrap tires appear similar to the reference compounds prepared with DAE oil. However, the ageing resistance of the pyrolysis oil are worse than the reference compound with DAE oil.