Enhanced thermal conductivity and wear resistance of polytetrafluoroethylene via incorporating hexagonal boron nitride and alumina particles

Polytetrafluoroethylene (PTFE) receives wide attention in electronic packaging materials due to its excellent dielectric properties, friction properties and thermal stability. However, its extremely low thermal conductivity limits its further application. In this work, hexagonal boron nitride (h-BN) platelets are added into PTFE matrix to improve the thermal conductivity as the expense of largely deteriorated friction property. To make up the loss of friction property, alumina particles (AO) are also added and the effects of filler ratio between h-BN and alumina on the thermal conductivity and tribological performance of PTFE composites are investigated. It is interesting to find that when the filler ratio of h-BN and alumina is fixed at 2:1, the through-plane and in-plane thermal conductivity of PTFE composite filled with 30 vol% hybrid filler can be increased to 1.544 Wm(-1) K-1 and 2.029 Wm(-1) K-1 (5.5 and 5.7 times that of PTFE), respectively. Furthermore, the coefficient of friction of PTFE composites only increases by 21.32% and the wear rate decreased by 48.09%, compared with that of PTFE. Our work demonstrates a facile method to achieve much improved thermal conductivity of PTFE while maintaining its excellent dielectric properties and friction properties by using hybrid filler of h-BN and AO.