In order to improve the thermal conductivity of polyetheretherketone (PEEK), the ZA8 zinc aluminum alloy powder was used as a thermal conductive filler. PEEK / ZA8 thermal composites were prepared by the molding process. The effects of surface modification and ZA8 contents on the thermal conductivity and mechanical properties of PEEK / ZA8 composites were investigated. Meanwhile, the first-principle calculation method based on density functional theory was used to study the surface adsorption characteristics and interface bonding mechanism of the PEEK / ZA8. Results show that the thermal conductivity of the composites is improved after ZA8 surface modification, but the mechanical properties of the composites decreased with the increase of ZA8 content. When the ZA8 content is 40%, the thermal conductivity of the composites is 0.298 Wm^-1K^-1, which is 72.25% higher than that of pure PEEK. On this basis, 5 wt% graphite is added, the thermal conductivity is 0.418 Wm^-1K^-1, which is 40.27% higher than that of PEEK / ZA8 without graphite, and 141.62% higher than that of pure PEEK. The first-principle calculation results show that the existence of hydroxyl group can change the adsorption properties of aluminate on Zn (001) surface. From physical adsorption to chemical adsorption, the bond strength between aluminate and Zn surface is greatly improved

Keywords: thermal conductivity, interface bonding mechanism, first-principle, hydroxyl group, aluminate