Effect of Aromatic OIL on PHASE Dynamics of S-SBR/BR Blends for Passenger CAR Tire Treads

Wednesday, October 12, 2016: 10:45 AM
Akansha Rathi1, Marianella Hernández2, Wilma K. Dierkes3, J.W.M. Noordermeer3, Cristina Bergmann4, Juergen Trimbach5 and Anke Blume3, (1)Elastomer Technology and Engineering, University of Twente, Enschede, Netherlands, (2)Novel Aerospace Materials, Delft University of Technology, Delft, Netherlands, (3)Engineering Technology, University of Twente, Enschede, Netherlands, (4)R&D, Hansen & Rosenthal KG, Hamburg, Germany, (5)R&D, Hansen & Rosenthal Group, Hamburg, Germany
Even though S-SBR/BR blends are commonly used for passenger car tire treads, little is known about the phase dynamics arising from the local morphological heterogeneities. The present study aims the understanding of: (i) the influence of aromatic oil on the dynamics of the individual phases in S-SBR/BR blends, and (ii) the preference of  the specific oil in either phase.

S-SBR/BR (50/50) blends with varying concentrations of aromatic oil were studied. Conventional techniques for the determination of Tg (glass transition temperature or α-relaxation process), such as Differential Scanning Calorimetry and Dynamic Mechanical Analysis were of limited use for fulfilling the aim. Therefore, Broadband Dielectric Spectroscopy, a more sensitive technique to study the α-relaxation process was employed. It was possible to de-convolute the dielectric loss (ε") peak of the vulcanized blends into two super-positioned relaxation processes, α' and α (in increasing order of frequency), which were attributed to the S-BR and BR phases, respectively. The distinct effective Tg’s (Tgeff) of the S-SBR and BR phases varied with the amount of aromatic oil added. Tgeff of the BR phase was close to the Tg of virgin BR, whereas Tgeff of the S-SBR phase was close to the blend average Tg. This is in accordance with the model for phase dynamics of miscible blends by Lodge and McLeish (2000). With this study novel insight into the dynamic heterogeneity of traditional S-SBR/BR blends is obtained.

Key words: S-SBR/BR blends, aromatic oil, phase dynamics, glass transition temperaturedielectric loss (ε")