Formation of more efficient thermally conductive pathways due to the synergistic effect of boron nitride and alumina in poly(3-hydroxylbutyrate)

PHB/BN/Al₂O₃ composites with high thermal conductivity were fabricated in melt blending process. A synergistic effect in the thermal conductivity enhancement of PHB composites was achieved. DSC results indicate that the crystallinity of PHB slightly changes and the XRD results show that the crystal forms of PHB remain unchanged. Additionally, the rheological properties indicate that thermally conductive fillers have formed thermally conductive pathways in PHB in the low frequencies. However, the viscosity of PHB composites remarkably decreases after the introduction of Al₂O₃ which facilitates the processibility of the PHB composites. Consequently, it can be suggested that more efficient thermally conductive pathways, originates from the alignment of BN on the Al₂O₃ surfaces, are formed due to the lower viscosity which leads to a decreased thermal interface resistance along the BN/Al₂O₃ hybrid filler network. This synergistic effect provides a method to acquire a polymer composite with higher thermal conductivity, but with lower viscosity.