Adhesion and tensile properties of an aged and non-aged SBR rubber blend,analyzed using Multiscale-Contact-Mechanics and a chemical kinetics aging Model

摘要

This study observed the effect of aging on a Styrene Butadiene-lsoprene(80:20)rubber blend.In particular,we investigated the adhesion between smooth glass and both non-aged and aged rubber.In addition,we also studied changes in morphology,elongation at break toughness,viscoelastic profile,and strain relaxation of the rubber with aging.The adhesion results show that the rubber was only slightly modified by the aging process up to 6 and 8 weeks at 80°C and 70°C respectively,but both the elongation at break and rubber toughness were greatly reduced.We attribute the later alteration to the age-induced formation of a low concentration of crack-like defects,which have negligible influence on adhesion,but a large effect on the rubber’s tensile properties such as elongation at break and toughness.The study also shows a decrease in the activation energies calculated from the frequency-temperature superposition(FTS)maximum of tangent 8 and the stress relaxation time-temperature superposition(TTS).Furthermore,there large difference observed in activation energies between the viscoelastic(-242 kJ/mol)and the strain relaxation(-83 kJ/mol)testing indicates the different nature of the aging processes addressed by both techniques.Consequently when studying the aging behavior of elastomers is of paramount importance to probe the functionally-critical properties of the elastomer depending of the application.