Improved thermal conductivity of immiscible polyamide 6 (PA6)/polyolefin elastomer (POE) blend by controlling selective localization of aluminum nitride (AlN)

The effect of selective localization of aluminum nitride (AlN) on the thermal conductivity of immiscible polyamide 6/polyolefin elastomer (PA6/POE/70/30) was studied. Morphological characterization proved that the neat blend had droplet-matrix morphology, and adding 10% (by wt) AlN to the minor phase resulted in stable co-continuous morphology formation. We have shown that the localization of AlN depends on the interfacial tensions between different blend components. AlN, which was first wetted by POE phase, tended to migrate to the interface due to thermodynamic tendency. AlN was first wetted by the PA6 phase following its dispersion in this phase. The rheological results confirmed the strong peculated structure formed in 70/30/10 (PA6/POE/AlN) sample and better thermal conductivity compared to pure blend. The thermogravimetric measurement revealed that the thermal stability of the composite with a double percolation structure increased by 8 °C compared to the pure sample. DSC analysis results showed that the crystallinity of 70/30/10 (PA6/POE/AlN) sample decreased nearly 25% due to increased interfacial area. The impact strength of 70-30-AO₁₀ reached 8.8 kJ.mm^–2, which was about 2 times higher than the pure PA6. The thermal conductivity of PA6/POE composite with 10% (by wt) AlN was enhanced to 3.76 W.(mK)⁻¹, nearly nine times higher than the pure blend. In summary, a stable co-continuous morphology with high thermal conductivity, fairly good mechanical properties, and low percolation threshold were obtained in immiscible (PA6/POE/70/30) blend by controlling the selective localization of 10% (by wt) AlN particles which can be a perspective for designing and producing composites especially in electronic devices.

Graphical abstract