Chemical resistance evaluation of polystyrene / polypropylene blends : effect of blend compositions and SEBS comtent

Abstract

The present study investigates the effect of styrene-b-(ethylene-co-butylenes)- b-styrene (SEBS) and blend ratio on the chemical resistance of PS/PP blends. Using a Brabender PL2000 twin-screw extruder, blends of PS rich PS/PP (composition ranging of 90–60 wt % PS) containing different amount of SEBS were prepared and injection moulded to be evaluated for chemical resistance. The results showed that the chemical resistance of PS to acetone and tetrahydrofuran (THF) increased with increasing PP content. The chemical resistance of PS/PP blends increased with increasing SEBS content at relatively lower PP content but decreased with increasing SEBS content at higher PP content. Dynamic mechanical analysis showed that 60/40/25 PS/PP/ SEBS blends had better miscibility than 60/40/5 PS/PP/SEBS blends. However better miscibility did not result in enhanced chemical resistance since SEBS itself was effected by the chemicals