On the mechanical properties of co-continuous polymer blends: experimental and modelling

Abstract

Mechanical properties of polymer blends with co-continuous morphologies were measured and compared to the properties of blends of the same polymers with a droplet/matrix morphology. For this purpose, poly(ether–ester)/PS and SEBS/PP blends were prepared with both morphologies, which was facilitated by the rheological properties of the block copolymers. The elastic moduli of co-continuous blends were significantly higher than the moduli of the dispersed blends, but no significant difference in tensile or impact strength was found when co-continuous blends were compared to blends with a droplet/matrix morphology. A model was proposed depicting the basic element of co-continuous structures as three orthogonal bars of one component embedded in a unit cube where the remaining volume was occupied by the other component. This model was shown to predict the moduli of polymer blends with co-continuous morphologies over the complete composition range.