Abstract: Polyamide 6 (PA6)/boron nitride (h-BN) composites with a high thermal conductivity were prepared via melt compounding. A silane coupling agent, KH 550, and a titanate coupling agent, TM-P, were used to enhance the interfacial adhesion between PA6 and h-BN and also improve the thermal conductivity. An orthogonal experiment was conducted to investigate the effects of the particle size of h-BN, the loading of h-BN and the amounts of coupling agents on the thermally conductive performance of composites. The results indicated that the optimum amounts of coupling agent used were 2.5 wt % and 1 wt% for KH550 and TM-P, respectively, when the loading of h-BN was set to 20 vol %. TM-P exhibits a better modification effect than KH 550, thus leading to a higher thermal conductivity. The thermal conductivity of composites showed an increase at first and then began to decline with an increase of h-BN loading, but the yield strength tend to decrease. The composites achieved much better mechanical properties when using TM-P as a coupling agent. An optimum processing condition was obtained as follows: the content of h-BN was set to 25 vol % and the particle size of h-BN was determined as 10~15 μm. Under this condition, the composites achieved a thermal conductivity of 2.446 W/(m·K).

Key words: boron nitride, polyamide 6, coupling agent, thermal conductivity