Mechanical properties and morphologies of polypropylene composites synergistically reinforced-toughened by styrene-butadiene rubber and graphene oxide nanosheets

Chemically reduced graphene (C-rGO) nanosheets were first prepared from graphene oxide (GO), and then the polypropylene (PP) composites synergistically reinforced-toughened by styrene-butadiene rubber (SBR), and C-rGO nanosheets were fabricated via melt blending. The mechanical properties of PP can be considerably improved by synergistically filling with C-rGO nanosheets and SBR, especially for the notched Izod impact strength (IS). The results from the X-ray diffraction, polarizing optical micrographs, scanning electron microscope, differential scanning calorimetric, dynamic mechanical analysis, and thermogravimetric analysis measurements reveal that: (1) the beta-phase crystal structure of the PP is formed when the C-rGO and SBR are synergistically filled with PP and its formation plays a role for the enhancement of the impact strength for PP/SBR/C-rGO composites; (2) the dispersion of the C-rGO and SBR in the PP/SBR/C-rGO composites is homogeneous, indicating that synergistic incorporating method decreases the aggregation of nanosheets and thus increases the sites for dissipation of shock for impact energy in the PP/SBR/C-rGO composites; and (3) the thermal analysis shows high thermal stability for the PP/SBR/C-rGO composites.