Strain energy density of carbon-black-loaded rubber vulcanizates

The strain energy density behaviour is studied at room temperature, for 100 phr (parts per 100 parts of rubber by weight) FEF carbon-black-loaded styrene-butadiene rubber (SBR), natural rubber (NR), butadiene-acryle nitrial rubber (NBR), butyl rubber (IIR) and butadiene rubber (BR). This behaviour is also studied for 100 phr of different types of carbon-black, (intermediate super abrasion furnace) (ISAF), high abrasion furnace (HAF), fast extrusion furnace (FEF), semi-reinforcing furnace (SRF) and easy processing channel (EPC)-)loaded SBR rubber vulcanizates and for different concentrations of FEF carbon-black-loaded SBR rubber vulcanizates. The shear modulus for all composites is also obtained and discussed. These data are used to calculate the strain energy density using the equation proposed by Blatz et al (1974 Trans. Soc. Rheol. 18 145-61), based on the n -measure of Sethe. It is found that the n -measure is still a material constant, even after the addition of carbon black, but with higher values than that for unloaded rubber.