Hybrid nanoparticles with different surface chemistries show higher efficiency in compatibilizing immiscible polymer blends

This study demonstrated that a higher efficiency of fumed silica nanoparticles in compatibilizing polypropylene (PP)/polystyrene (PS) blends can be achieved by replacing a small portion of hydrophobic nanoparticles (R974) with hydrophilic ones (A200). Calorimetric and morphological analysis indicated that both hydrophobic and hydrophilic silica nanoparticles possessed good morphological refinement effect on the PP/PS (20/80) blends through different compatibilization mechanisms. The two-step mixing method was more efficient than the one-step mixing method in preparing blends with compatibilized morphology. A higher refinement of the domain size and more profound fractionated crystallization phenomenon in PP/PS blends were observed with simultaneously adding R974 nanosilica and a small amount of A200 nanosilica. This suggested that different compatibilization mechanisms of nanosilica could work synergistically to refine the morphology of polymer blends.