Impact of processing conditions on interactions between silica and functionalized SBR
Styrene butadiene rubber (SBR) was initially developed as a substitute for natural rubber and became the most widely used synthetic rubber in the tire industry. Environmental concerns lead to solutions to reduce rolling resistance to reduce fossil fuel consumption. Rolling resistance can be reduced by replacing carbon black with silica with silanes in the formulation of SBR compounds, and is influenced by the way the particle interacts with the polymer chains. The insertion of functional groups into the SBR chain to form functionalized SBRs (f-SBR) enables, for example, to increase interaction with the silica or to immobilize chain segments via primary and/or secondary bonds. If f-SBRs are prominent in the tire industry, it is necessary to understand the interactions between functional groups and silica, and optimize processing conditions to favor these interactions for each functionalization. In this study, three f-SBRs with different functionalizations were chosen. The work aims to identify the reactions that occurred between silica and f-SBR polymers during the mixing process and the degree of polymer charge interaction achieved by solid NMR, FTIR and torque rheometer. From these results, different mixing conditions with a Bambury type mixer are explored, varying times and temperatures to understand the influence of the properties of the compounds.