Poly(ether-ketone)/Silica Nanocomposites: Storage Modulus and Hardness

Abstract Dynamic mechanical properties of the poly(ether-ketone) (PEK) based nanocomposites reinforced with 0–30 wt.% (0-20.2 vol.%) SiO₂ nanoparticles (20–40 nm) were investigated at 1 Hz over the temperature range of 30–250°C for the application in printed circuit boards/electronic substrates. It was found that uniform dispersion of SiO₂ nanoparticles in the PEK matrix resulted in significant increase in storage modulus and microhardness. The highest increase in storage modulus measured at 50 ℃ (glassy region) and 250 ℃ (rubbery region) was more than 100% and 250% than that of neat PEK, respectively. A linear relationship between the storage modulus and microhardness of the nanocomposites with a correlation factor (R²) of 0.96 was obtained. The ratio of storage modulus to microhardness (E′/H) was ~ 0.09. The nanocomposites exhibited lower peak values of the tan δ than that of neat PEK. Scanning electron microscopy revealed good interfacial adhesion between the PEK matrix and the SiO₂ nanoparticles which was validated by Kubat parameter. The glass transition temperatures determined from the loss modulus and tan δ are slightly increased for the nanocomposites. However, differential scanning calorimetry could not detect glass transition temperature.