Effect of BaTiO3 on the Mechanical Properties of Nitrile-Butadiene Rubber (NBR) Vulcanizates

The effect of BaTio3 content on the elastic behaviour of Nitrrile-
Butadiene Rubber (NBR) vulcanizates loaded with 65 phr of Super Reinforced
Furnace (SRF) black has been studied by carrying out equilibrium stress-strain
measurements at 300K. Young’s modulus (E) and the number of effective chains
per unit volume (ν) as a function of BaTiO3 content were calculated. A small
increase at low contents was detected followed with a large decrease at high
concentrations. The average molecular weight (Me) was found to have an
opposite behaviour of (ν). The maximum change in entropy (ΔSmax) and the
work done (W) on rubber chains during extension were found to decrease
slightly at low loading followed with a high increase at high BaTiO3 loadings.
Stress-strain cycling was also carried out and hysteresis was found. The energy
density loss and the remnant strain after each cycle were also studied.