Thermoplastic polypropylene/aluminum nitride nanocomposites with enhanced thermal conductivity and low dielectric loss

Polymer dielectrics with high thermal conductivity and low dielectric loss are highly attractive for applications in electric and electronic industry. In this paper, surface modified aluminum nitride (AlN) nanoparticles were introduced into polypropylene (PP) matrix via melt blending to prepare thermoplastic dielectrics with enhanced thermal conductivity and low dielectric loss. The microstructure, DC conductivity, dielectric properties, breakdown strength, space charge behavior, thermal conductivity and thermal stability of the nanocomposites were investigated. It is found that the inclusion of surface modified AlN nanoparticles results in improved thermal conductivity and thermal stability of PP/AlN nanocomposites. The dielectric constant shows a slight increase with AlN nanofiller content, and the dielectric loss remains at very low level of below 0.003. DC conductivity of PP/AlN nanocomposites increases but shows desirable weak dependence on electric field. DC and AC breakdown strength slightly decrease with the AlN nanoparticle content but it is still high enough for dielectric applications. More importantly, the PP/AlN nanocomposites is a thermoplastic material which is potential to be recycled and has less impact on the environment.