Fractal structures of PA6/POE blend nanocomposites and their dynamic properties

We investigate the effect of minor phase rheological properties and compatibilizer on the phase morphology and graphene 3D structure in polyamide-6 (PA6)/polyolefin elastomer (POE) blends. It is revealed that in blends containing low viscosity (LV) POE, graphene is better dispersed facilitating its localization at the interface. In the blend containing high viscosity (HV) POE with poor graphene dispersion, large graphene aggregates are observed inside the POE phase with less interfacial coverage. Interestingly, graphene induces a co-continuous morphology and electrical and rheological percolation in both systems, although at a lower graphene content for the LV system. The LV system exhibits a more interconnected morphology, while in the HV system we observe a compact fractal-like POE structure with a lower degree of interconnectivity. Our morphological observation suggests that co-continuous morphology in the LV system is dominated by sheet formation, while in the HV system it is dominated by coalescence between moderately elongated domains. Fractal analysis of the graphene 3D network (based on the rheological characterization) is correlated with the higher degree of connectivity of the graphene 3D structure in the LV system. The 2D fractal dimension of the POE phase (host phase for graphene) is in line with the fractal dimension of the graphene flocs, indicating that the graphene flocs influence the blend morphology. The addition of compatibilizer to the HV system did not result in improved electrical properties.

Automated summary

We investigated the influence of minor phase rheological properties and compatibilizer on the phase morphology and graphene 3D structure in PA6/POE blends. It was found that in blends with low viscosity POE, graphene dispersed better and localized at the interface. In blends with high viscosity POE and poor graphene dispersion, large graphene aggregates were observed inside the POE phase with less interfacial coverage. Interestingly, graphene induced co-continuous morphology and electrical and rheological percolation in both systems, although at a lower graphene content for the low viscosity system. Morphological observations suggested that sheet formation dominated the co-continuous morphology in the low viscosity system, while coalescence between moderately elongated domains dominated in the high viscosity system. Fractal analysis of the graphene 3D network showed a higher degree of connectivity in the low viscosity system. The addition of compatibilizer did not improve the electrical properties in the high viscosity system.