Study on the influence of silane coupling Agent-Modified BN on the thermodynamic properties of polytetrafluoroethylene

Abstract To study the effect of different silane coupling agents modified boron nitride (BN) fillers on the thermodynamic properties of PTFE, this work selects KH550, KH560, and KH580 silane coupling agents to modify BN, and constructs a PTFE composite model in Materials Studio . The thermal conductivity, mechanical properties, and cohesive energy density of the composite models are analyzed using molecular dynamics methods. The results indicate that coupling agent modification can further improve the thermodynamic stability of the composite. Among them, KH550 has the optimal modification effect, with a thermal conductivity of 0.192 W/(m·K), an increase of 66.9% compared to the pristine. The underlying mechanism for the improvement of thermodynamic properties is elucidated from the perspectives of molecular thermal motion and intermolecular interaction forces through the calculation of cohesive energy density as well as the fractional free volume. This study provides theoretical guidance for the screening of coupling agent modification and the design of high-performance polymer composite based on molecular simulation.