Thermal, mechanical and dielectric properties of flexible BN foam and BN nanosheets reinforced polymer composites for electronic packaging application

A series of novel flexible polymer composites consisted of boron nitride foam (BNF), boron nitride nanosheets (BNNS) and polydimethylsiloxane (PDMS) were designed and fabricated by vacuum-assisted infiltrating BNNS/PDMS mixtures into 3D BNF synthesized via chemical vapor deposition (CVD). Their microstructure, thermal, mechanical and dielectric properties were studied. Contributed to the interconnected networks of BNF and synergistic effect of BNNS with BNF, 10 wt% BNNS/BNF/PDMS composite shows a high thermal conductivity of 0.56 W m−1 K−1, high heat resistance index of 275.6 °C, 33% increment of Young's modulus compared to PDMS, relative permittivity of 3, dissipation factor of 0.0051, EMI shielding effectiveness of 1.5 dB at X band and breakdown strength of 21.8 MV/m. Due to the outstanding comprehensive properties, BNNS/BNF/PDMS composites have a promising potential application in wide electronic packaging field.