Effect of replacing EPDM with high molecular weight amorphous poly(۱-hexene) on the mechanical behavior of iPP/iPP-g-MA/EPDM blends

Varying amounts of a high molecular weight poly(۱-hexene) (PH, Mv=۱.۷×۱۰۶ Da) are substituted for EPDM in an iPP/iPP-g-MA/EPDM blend (weight ratio: ۷۶:۴:۲۰) and mechanical properties as well as phase morphology of the blends are studied and compared. The results show that by substituting the entire EPDM with PH, the tensile strength-at-break increases from ۱۸.۷ to ۲۱.۱ MPa, elongation-at-break increases from ۱۵.۵% to ۳۷۰.۸%, and impact strength increases from ۶.۴ to ۵۰.۱ kJ.m-۲. Dynamic mechanical thermal analysis (DMTA) of the blends proved their immiscibility and SEM analysis confirmed these findings by showing droplet-matrix morphologies. Studying the creep behavior of the samples shows that the blends containing PH have more creep so that by substituting all EPDM in the blends with PH, the permanent deformation increases from ۰.۴۲۵% to ۰.۵۰۵%. According to the results, PH is introduced as a candidate for improving the impact properties of iPP/iPP-g-MA/EPDM blend.

Keywords:

Rubber toughened iPP , Creep behavior , Two phase morphology , DMTA , Immiscible blends