Abstract
The substantial heat generation due to miniaturization and high-degree integration of electronic devices is one of the major issues to facilitate efficient thermal management in power electronics. Though epoxy-based composites have shown great interest in different applications such as laminated circuit board, electronic component encapsulations, and potting, they have low application temperature (up to 150 °C) and higher mismatch of coefficient of thermal expansion (CTE) between the heat source and heat sink. Here, poly(ether ether ketone) (PEEK) composites reinforced with hexagonal boron nitride (hBN) nanoplatelets have been developed by liquid mixing and re-melting method for a step change in composite materials with lower CTE and significantly improved thermal dissipation capability. The lowest achieved CTE is 2.1 µm m−1 K−1, and the highest thermal conductivity is 1.04 W m−1 K−1 in PEEK/hBN composites at 30 wt% hybrid hBN content (hBN platelets with two different sizes, i.e. 70 nm and 500 nm, taken as 1:1 weight ratio), due to the formation of thermally conductive inter-filler networks. The composites show negligible variation in K with the working temperature up to 250 °C. The developed composites also exhibit excellent electrical insulation properties; thus, they will have good potential in thermal management for power electronic applications.Graphical abstract
Highlights
The continuing miniaturization and increasing power output of electronic devices have created several challenges in thermal management and electronic packaging
The hexagonal boron nitride (hBN) nanoparticles are randomly distributed throughout the polymer matrix even after melting the mixed powders to get the bulk composite, which is shown as cross-sectional scanning electron microscopy (SEM) images in Fig. 1c, f
The composites with different filler loadings show additional diffraction peaks of hexagonal hBN at 2h of 26.6° and 41.6° corresponding to the reflection from (002) and (100) plane, respectively, indicating the phase of hBN nanoparticles remains unchanged inside the poly(ether ether ketone) (PEEK) matrix
Summary
The continuing miniaturization and increasing power output of electronic devices have created several challenges in thermal management and electronic packaging. Among the different inorganic fillers, hexagonal boron nitride (hBN) has attracted much attention due to their hightemperature stability, low dielectric constant, high electrical insulation, high heat and chemical resistance, good mechanical properties and extremely high thermal conductivity (300 W m-1 K-1 for inplane direction, K// and 30 W m-1 K-1 along through-plane direction, K\) with very low CTE (1.1–4.3 lm m-1 K-1) [24,25,26,27,28]. GNPs/CF [35] and CF/hBN/Cu [36] In this present work, we have investigated the effect of nano hBN loadings, and hybrid fillers with different hBN sizes (70 nm and 500 nm) on the thermal conductivity and CTE of PEEK/hBN composites. A flat sample of 2.5 mm thickness was placed between two electrodes, and measure the direct-current voltage applied to the electrode and the current flowing through the volume of the sample and dividing the two values, the volume resistivity of the composite was obtained
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