Interfacial effects on thermal conductive properties in PEEK composites

Polyether ether ketone (PEEK) is a high-performance thermoplastic composite matrix material renowned for its exceptional mechanical properties and thermal stability, making it highly suitable for high-temperature applications. However, the interfacial thermal resistance (ITR) at the micro-scale interfaces between the polymer matrix and fillers in PEEK composites, which significantly impacts heat transfer, has not been extensively explored. In this study, we investigated the interfacial thermal properties of PEEK composites with various filler materials using molecular dynamics simulations and the theoretical model. Our results indicate that PEEK/SiO₂ composites exhibit superior interfacial thermal properties compared to other selected materials, while PEEK/SiC composites display the highest interfacial thermal resistance. Due to the effect of ITR, the introduction of fibers may not always improve the effective thermal conductivity of the composite. The effect of ITR is also related to the filler size and shape. Reducing the size of the filler magnifies the effect of ITR, and there is a critical filler length which could be used to distinguish between the positive and negative thermal effects of introducing fillers. Our research illustrates a multiscale modeling approach to evaluate the ITR effect on the thermal properties of PEEK composite, which could be extended to other composite systems. The findings could benefit the multiscale modeling of composite manufacturing and the micro-structure design of composites with consideration of thermal management.