Carbon Nanotube and Carbon Black Filled SBR: Comparative Analysis

SBR was compounded with carbon black (CB) and multi-wall carbon nanotube (CNT) to systematically compare properties of compounds and their vulcanizates. The effects of filler loadings on rheology, bound rubber, vulcanization behavior of the compounds and crosslink density, mechanical properties, abrasion, electrical volume resistivity, morphology of the vulcanizates were investigated. At the same filler loadings, dynamic complex viscosity, storage modulus and maximum torque of curing of CNT-filled compounds were higher than those of CB-filled compounds. Also, the comparison indicated that the lower amount of bound rubber was found in CNT-filled compounds. Crosslink density, modulus at different strains, tensile strength and storage modulus of CNT-filled vulcanizates were higher. It was found that typically over two times larger amount of CB must be added to achieve properties similar to those of CNT-filled compounds and vulcanizates. Even the elongation at break of CNT-filled vulcanizates was found to be lower, their abrasion resistance was better. Tan δ at T_g and in the range of 0 to 60 °C of CNT-filled vulcanizates were lower and higher, respectively. The electrical percolation thresholds of CNT- and CB-filled vulcanizates were about 5 and 25 phr, respectively. Morphology of CNT- and CB-filled vulcanizates observed by AFM was compared.