TOUGHNESS ENHANCEMENT OF POLYAMIDE-6 MODIFIED WITH DIFFERENT TYPES OFRUBBER - THE INFLUENCE OF INTERNAL RUBBER CAVITATION

The toughening enhancement of Polyamide 6 blended with different types of functionalized elastomers was studied. Morphological analysis by s canning electron microscopy (SEM) were performed on undeformed samples in order to determine particle-size distribution. Yet more SEM examin ation of the damage zone ahead of notch tip in uniaxial tensile test p rovided insight into the failure mechanisms. The best impact strength was achieved with the PA6/EPDM-g-MA. (terpolymer ethylene-propylene-di ene monomer grafted with Maleic Anhydride) blend, unlike ULDPE-g-MA (u ltra-low-density polyethylene grafted with maleic anhydride), which po ssesses the poorest toughening efficiency even though opposite results would be expected from particle-size evaluation. The higher cavitatio n resistance of EPDM compared to ULDPE observed during low strain rate tensile test plays a crucial role in understanding the best performan ces of its blends. (C) 1997 John Wiley & Sons, Inc.