MWCNTs Elastomer Nanocomposite, Part 2: The Addition of MWCNTs to an Oil-extended SBR-based Carbon Black-filled Rubber Compound

Multi-walled carbon nanotubes (MWCNTs) were tested in a styrene-butadiene copolymer (E-SBR)-based rubber compound as partial replacement of N375 carbon black at 5 and 10phr level. The composite studied was characterized by a high content of plasticizing oil. It is shown by the increase of the apparent shape factor of the MWCNTs that the oil permits a better dispersion and alignment of the MWCNTs in the rubber matrix. The reinforcing effect of MWCNTs has been studied both on sulphur-cured and radiation-cured nanocomposites. In both cases, a strong reinforcing effect has been measured at low elongations, but the extra-reinforcement tends to disappear at higher elongations due to the poor interaction between the MWCNTs surface and the rubber matrix. The presence of high levels of plasticizer permits to partially reduce the strong heat build up and hence the strong mechanical hysteresis normally observed in nanocomposites prepared with MWCNTs.