Thermal conductivity enhancement of poly(3-hydroxylbutyrate) composites by constructing segregated structure with the aid of poly(ethylene oxide)

Thermally conductive poly (3-hydroxylbutyrate) (PHB)/poly (ethylene oxide) (PEO)/boron nitride (BN) composites were fabricated by powder mixing. The thermal conductivity of PHB composite was remarkably enhanced by incorporating a small amount of PEO. SEM images revealed that segregated and co-continuous structures were formed in PHB composites. Owing to the addition of PEO, acting as a binder, BN particles were able to stack more closely and covered larger size of PHB aggregates than PHB/BN composites did. In addition, the partial miscibility between PHB and PEO could efficiently improve the interaction between BN particles and PHB matrix. Besides, during the hot pressing process, PEO could penetrate into the voids existing between BN particles and lead the phonon scattering to decrease. The hydrogen bonding existed between PEO and BN particles also played an important role to the thermal conductivity enhancement of PHB composites. These factors combined were believed to result in higher thermal conductivity of PHB/PEO/BN composites than PHB/BN composites fabricated by powder mixing.