Coefficient of thermal expansion and thermal conductivity of poly(ether-ketone)–silica nanocomposites for electronic packaging substrate

The current study discusses the fabrication of poly(ether-ketone) (PEK)–SiO2 nanocomposites containing 0–30 wt% SiO2 nanoparticles using an industry-friendly planetary ball mill in a controlled atmosphere followed by hot pressing. The ball milling technique resulted in excellent and uniform dispersion of SiO2 nanoparticles in the PEK matrix. The linear coefficient of thermal expansion (CTE) of the nanocomposites was reduced by 30% while the thermal conductivity increased significantly. It was also observed that annealing of the samples above the glass transition temperature further improved the thermal conductivity of neat PEK and its nanocomposites. However, there was a minimal increase in the dielectric constant (< 4.1) and dissipation factor (< 0.006) for the nanocomposites over the studied frequency range. The volume resistivity of the nanocomposites was affected insignificantly and the nanocomposites remain insulating. Thus, the proposed PEK/SiO2 nanocomposites might be potential futuristic materials for the electronic packaging substrates and printed circuit boards requiring their use at high temperatures.