Ethylene-octene copolymer (POE) toughened polyamide 6/polypropylene nanocomposites : effect of POE maleation

Abstract

Ethylene-octene elastomer (POE) and ethylene-octene elastomer grafted maleic anhydride (POEgMAH) toughened nanocomposites of polyamide 6/polypropylene (PA6/PP) containing 4 wt% organophilic modified montmorillonite (MMT) were produced by melt compounding followed by injection moulding. The PA6/PP composition was kept constant (PA6/PP = 70/30 parts) while the elastomer (either POE or POEgMAH) content varied between 5 and 20 wt%. PP grafted maleic anhydride (PPgMAH) was used to compatibilize the blend system. The impact strength of the nanocomposite system was examined by the conventional Izod impact test at room temperature (RT). In addition, linear elastic fracture mechanics (LEFM) approach was used to study the fracture response of the notched three point bending type specimens at room temperature (RT) and -40 degrees C. Fracture surfaces of the broken specimens were examined using scanning electron microscopy. The results show that while POEgMAH can remarkably improve the compatibility between PA6 and the elastomer thus increasing the toughness, the unmodified POE has less significant contribution to PA6/PP/organoclay toughness. Elastomer domains of POEgMAH show a finer and more uniform dispersion than that of POE in the PA6/PP/organoclay matrix. It is also observed that the toughness increased with the increasing elastomer concentration for both unmaleated and maleated POE.