Polystyrene/polycarbonate blends compatibilization: Morphology, rheological and mechanical properties

The compatibilization of PC/PS (70/30 wt%) blends was realized by the addition of 1.125, 2.5 and 5 wt% of SEBS-g-PC. SEM pictures revealed that the droplet-matrix microstructure was refined, from droplets of 0.787 μm diameter to 0.420 μm. The complex viscosity decreased, and, correlated to the size of the droplets, was the result of the decrease of the interfacial tension between PC and PS. The transition temperature of the PS increased for 12 °C with 5 wt% of SEBS-g-PC, showing a compatibilizing effect of this copolymer. The two maxima observed in Van Gurp–Palmen plots merger confirming the compatibilization. Finally, mechanical properties were widely improved. Impact strength evolved from 3.8 to 6.9 kJ m−2, and elongation at break was multiplied by two (from 19.6 to 40.5%) when 5 wt% of copolymer is added. The interfacial adhesion increase was due to the compatibilization effect of the SEBS-g-PC onto PC/PS blends.