The impact of Janus nanoparticles on the compatibilization of immiscible polymer blends under technologically relevant conditions.

Several hundred grams of Janus nanoparticles (d ≈ 40 nm) were synthesized from triblock terpolymers as compatibilizers for blending of technologically relevant polymers, PPE and SAN, on industry-scale extruders. The Janus nanoparticles (JPs) demonstrate superior compatibilization capabilities compared to the corresponding triblock terpolymer, attributed to the combined intrinsic properties, amphiphilicity and the Pickering effect. Straightforward mixing and extrusion protocols yield multiscale blend morphologies with "raspberry-like" structures of JPs-covered PPE phases in a SAN matrix. The JPs densely pack at the blend interface providing the necessary steric repulsion to suppress droplet coagulation during processing. We determine the efficiency of JP-compatibilization by droplet size evaluation and find the smallest average droplet size of d ≈ 300 nm at 10 wt % of added compatibilizer, whereas at 2 wt %, use of JPs is most economic with reasonable small droplets and narrow dispersity. In case of excess JPs, rheological properties of the system is changed by a droplet network formation. The large-scale synthesis of JPs, the low required weight fractions and their exceptional stability against extensive shear and temperature profiles during industrial extrusion process make JP promising next generation compatibilizers.