TDAE aromatic oil preference for polymer blends: An analysis of S-SBR, BR, and miscible S-SBR/BR systems

This study assesses the impact of Treated Distillate Aromatic Extract (TDAE) oil, at concentrations of 0–20 parts per hundred rubber (phr), on the glass transition temperature (Tg) of High Vinyl/Low Styrene Styrene-Butadiene Rubber (HVLSS-SBR), polybutadiene rubber (BR), and their blends with weight ratios of 70/30 and 50/50. Using Dynamic Mechanical Analysis, Broadband Dielectric Spectroscopy, and Positron Annihilation Lifetime Spectroscopy, we found that TDAE modifies Tg and fractional free volume (Fv) differently across materials. In HVLSS-SBR, TDAE reduced Tg by approximately 10 °C and increased Fv by 0.8 %. In BR, TDAE raised Tg by 5–7 °C without altering Fv. The 70/30 blend showed no Tg change but a 0.6 % Fv increase. For the 50/50 blend, one Havriliak-Negami equation indicated a Tg rise of 2–3 °C and a 0.4 % Fv increase. A two-equation analysis revealed a 6 °C Tg increase and 0.9 % Fv boost in the BR-rich phase, versus a 2 °C rise and 0.3 % Fv uptick in the HVLSS-SBR-rich phase. The sequence of compatibility, influenced by TDAE, is crystalline BR > amorphous BR > HVLSS-SBR >70/30 blend >50/50 blend. This study provides valuable insights into the behavior of TDAE oil in rubber blends and can serve as a basis for further research in this field.