Abstract
The mechanical properties and morphologies of PP/SBR/SiO~2~ nanocomposites have been studied using mechanical testing, wide‐angle X‐ray diffraction (WAXD), polarizing optical microscopy (POM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The mechanical properties of neat polypropylene can be considerably improved by synergistically filling with SiO~2~ and SBR nanoparticles, especially for the notched Izod impact strength. The results from the WAXD, POM, SEM, DSC, and TGA measurements reveal that: (i) the β‐phase crystal structure of PP is formed when SiO~2~ and SBR nanoparticles are synergistically filled with polypropylene and its formation plays a role for the enhancement of the impact strength for PP/SBR/SiO~2~ nanocomposites; (ii) the dispersion of SiO~2~ and SBR nanoparticles in PP/SBR/SiO~2~ composites is homogeneous, indicating that synergistic incorporating method decreases the aggregation of nanoparticles and thus increases the sites for dissipation of shock for impact energy in PP/SBR/SiO~2~ nanocomposites; (iii) the thermal analysis shows high thermal stability for the PP/SBR/SiO~2~ nanocomposites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008