POLYSTYRENE EVA MELT BLENDS COMPATIBILIZED WITH EVA-GRAFT-POLYSTYRENE/

The influence of poly [(ethylene-co-vinyl acetate)-g-polystyrene] (EVA -g-PS) on the mechanical and morphological properties of polystyrene a nd the blends with EVA copolymers has been investigated. The melt blen ds have been performed in a twin-screw extruder. The addition of the g raft copolymer enhances the mechanical properties and impact resistanc e of the PS matrix and PS/EVA (90 : 10 wt %) blends. Better results on impact strength and elongation at break have been achieved by using a EVA-g-PS graft copolymer with a higher EVA proportion by weight. This graft copolymer also contains a lower molecular weight of the PS-graf ted segments than the PS matrix. Morphological studies by scanning ele ctron microscopy revealed some interfacial adhesion between the compon ents in the compatibilized polymer blends. (C) 1997 John Wiley & Sons, Inc.