Cocontinuous morphology of immiscible high density polyethylene/polyamide 6 blend induced by multiwalled carbon nanotubes network

The effect of functionalized multiwalled carbon nanotubes (FMWCNTs) on the phase morphology of immiscible high density polyethylene/polyamide 6 (HDPE/PA6, 50/50) blend has been investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study both the morphology variation of the nanocomposites and the selective distribution of FMWCNTs in the nanocomposites. It is clear that adding small amount of FMWCNTs (<2.0 wt.%) does not exert profound influence on the sea-island morphology of the nanocomposites. However, at moderate content of FMWCNTs (2.0 and 5.0 wt.%), a typical cocontinuous morphology is detected. Further increasing FMWCNTs content (10.0 wt.%) induces phase inversion. The crystallization behaviors of both HDPE and PA6 components were investigated by using differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). The results show the apparent nucleation effect of FMWCNTs for PA6 crystallization due to the selective distribution of FMWCNTs in PA6 phase. Rheological measurements exhibit the presence of FMWCNTs network structure in the nanocomposites. It is suggested that the formation of the cocontinuous morphology and the novel crystallization behaviors of PA6 at high content of FMWCNTs are ascribed to the formation of the FMWCNTs network structure.

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► We detected the morphology changes of HDPE/PA6 (50/50) with the increase of FMWCNTs content.
► The selective distribution of FMWCNTs in the nanocomposites was characterized.
► We detected the formation of FMWCNTs network structure in the nanocomposites.
► A model was suggested to explain the mechanism of the morphology changes.