The static mechanical properties, such as tensile strength, mod- ulus at 100% and 300% elongation, and reinforcing index (RI) were investigated, and the results are shown in Fig. 7. It can be observed in Fig. 7A that with increasing modification temperature, the mod- ulus at 100% elongation of the MSaDT/SSBR composites increases obviously, reaches a maximum at 50 °C, and then decreases with the modified temperature rising from 30 °C to 70 °C. The modulus at 300% elongation of the composites shows the same tendency as the modulus at 100%. As shown in Fig. 7B, the tensile strength of the composites also has a peak (a value of 15.5 MPa) at the modi- fication temperature of 50 °C. Some researchers [2,35] considered that the reinforcing effect of filler filled rubber composites can be measured by the reinforcing index (RI), which is the ratio of the modulus at 300% elongation to that at 100% elongation. A high value of RI corresponds to high reinforcing effect and strong rub- ber–filler interaction. As shown in Fig. 7B, the variation of RI fol- lows the same trend as that of tensile strength, modulus at 100% elongation, and modulus at 300% elongation, indicating that the modification temperature of 50 °C is best for silica modification. At this temperature, the silica combined with TESPT by strong chemical bonds, and TESPT improves the compatibility between the rubber matrix and silica, resulting in the enhancement of rub- ber–filler interaction, which can be intuitively reflected by the sta- tic mechanical properties.