Nylon toughened with functionalized EPDM rubber: Morphology and properties

Rubber-toughened nylon blends were prepared by melt-mixing nylon-6 with ethylene-propylene-diene rubber (EPDM), maleated EPDM (M-EPDM) or zinc sulfonated EPDM (Zn-SEPDM). In each case, blends covering a composition from 0-50 wt % were prepared by letting-down a 50/50 masterbatch of the polyamide and the rubber. Testing was done to determine the effect of type and content of rubber on mechanical properties and impact toughness. 1% secant modulus and tensile strength decreased with increasing rubber content in all cases. Elongation at break also decreased with increasing rubber content, but only to a small extent in the case of blends with the M-EPDM probably due to reaction between the rubber and nylon-6 during extrusion. The addition of rubber increased the notched impact toughness in all cases with the greatest enhancement occurring when M-EPDM was used.