Mir Hamid Reza Ghoreishy - Department of Rubber Processing and Engineering Group, Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box: 14975-112, Tehran, Iran.
Ghasem Naderi - Department of Rubber Processing and Engineering Group, Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box: 14975-112, Tehran, Iran.
Bahram Roohandeh - Department of Rubber Processing and Engineering Group, Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box: 14975-112, Tehran, Iran.

This research work is devoted to the study of the effect of ozone degradation on the hyperelastic behavior of a sidewall compound based on NR/BR blend. Two hyperelastic equations namely as Yeoh and Arruda-Boyce models were selected. Four rubber compounds in which all ingredients were kept similar except for paraffin wax were prepared and tensile tests were carried out on them before and after exposing to ozone. Paraffin wax is well-known for its anitiozonant effect. The parameters of the models were determined using uniaxial test data in conjunction with an appropriate curve fitting method. It was shown that the parameters of these models changes significantly with ozone and wax content. The initial shear modulus and chain extensibility factor were also calculated from the computed values of the model parameters. It was also shown that these physical parameters are directly related to the structure of the polymer chains and degradation occurred inside them

Hyperelastic models - Ozone degradation - Tire sidewall