Abstract

Polymer blending is commonly used to engineer materials with favorable properties. Due to the low entropy of mixing, in most cases, polymer blending results in a phase-separated morphology which governs the ultimate properties. Nanoparticles can significantly alter the phase morphology even at low contents. In the case of droplet-matrix morphology, the addition of nanoparticles can cause refinement, produce large and irregular domains, or even induce a co-continuous morphology. By employing a proper strategy of mixing for a particular system it is possible to manipulate the morphology and achieve desired properties. In this study, I investigate the impact of graphene particles on the phase morphology and mechanical and electrical properties of polyamide 6/ polyolefin elastomer blends. It is shown that a wide range of properties can be obtained by changing the composition and the localization of graphene. Inducing a co-continuous morphology at low graphene host phase content results in unique mechanical and electrical properties. The mechanism of graphene-induced co-continuity was further investigated by changing the rheological properties of the POE and the addition of compatibilizer. I found that the final phase morphology is governed by the structural features of the graphene network structure which in turn is dependent on the self-assembly of graphene particles.
The graphene 3D structure and phase morphology are not stable and evolve during annealing. Rheological and morphological characterization were employed to track the evolution of microstructure and correlate the relationship between self-similar graphene 3D structure and phase morphology. It is revealed that the graphene content and annealing time have the same impact on the rheological and electrical properties.