Thermal conductivity of polymer composites with oriented boron nitride

•Thermal conductivity depended on the orientation of BN in the polymer matrices.•Hexagonal boron nitride (BN) particles were treated by C27H27N3O2 and C14H6O8.•Amphiphilic-agent-treated BN particles are more easily oriented in the composite.•BN/PVA composites with C14H6O8-treated BN showed the highest thermal conductivity.•Thermal conductivity of the composites was compared with several theoretical models.

Thermal conductivity of boron nitride (BN) with polyvinyl alcohol (PVA) and/or polyvinyl butyral (PVB) was investigated as a function of the degree of BN orientation, the numbers of hydroxyl groups in the polymer matrices and the amphiphilic agents used. The composites with in-plane orientation of BN showed a higher thermal conductivity than the composites with out-of-plane orientation of BN due to the increase of thermal pathway. For a given BN content, the composites with in-plane orientation of BN/PVA showed higher thermal conductivity than the composites with in-plane orientation of BN/PVB. This result could be attributed to the improved degree of orientation of BN, caused by a larger number of hydroxyl groups being present. Those treated with C14H6O8 amphiphilic agent demonstrated a higher thermal conductivity than those treated by C27H27N3O2. The measured thermal conductivity of the composites was compared with that predicted by the several theoretical models.

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