Thermal, dielectric, and mechanical properties of h-BN-filled PTFE composites

摘要

In order to obtain materials for improved printed circuit boards (PCBs) with high thermal conductivity and low dielectric losses, hexagonal boron nitride (h-BN) was incorporated into a polytetrafluoroethylene (PTFE) matrix. The filler loading in the composite was varied up to a filler volume content of 50%. Thermal conductivity and coefficient of thermal expansion (CTE) were investigated with respect to filler orientation. Further dielectric and mechanical properties were investigated. The incorporation of h-BN improved the heat transport significantly, while the loss factor decreased. Fillers with a higher aspect ratio have a greater effect on increasing thermal conductivity. For a filler volume loading of 30%, the in-plane thermal conductivity was up to 14 times higher than the thermal conductivity of the matrix, while the loss factor decreased slightly. The permittivity increased with the increasing filler volume content, while the CTE also decreased. Though the filler affects the mechanical properties negatively, 40% of the tensile strength could be maintained if a filler volume content of 30% is not exceeded. Such compositions may be used as raw materials for future printed circuit boards. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46859.