LAUSR

Abstract In this study, the atmospheric plasma process (APP) was used to modify the surface of aluminum nitride (AlN) powder with different particle sizes and morphologies (non-spherical and spherical), using modified AlN powder as fillers for polydimethylsiloxane (PDMS) to form AlN/PDMS composites. The functional groups on the surface of the AlN powder, before and after APP modification of the AlN powder, were examined using a Fourier transform infrared spectrometer (FTIR). The thermal conductivity (k) of the sample was measured using a k measurement apparatus that conformed to the ASTM D5470-06 standard. In addition, the k of the sample with the highest k was further increased by the semi-curing technique. Finally, the applicable temperature range of the semi-cured sample was measured by thermogravimetric analysis (TGA). The results show that APP-modified AlN powder can be combined with a C–H functional group to make an APP-modified AlN powder with better adhesion to increase the k of the samples. The filling weight percentage of AlN powder had a nonlinear proportional relationship with k, and the spherical particles enhanced the k of the sample better than the non-spherical particles. The k values of 75 wt% APP-modified non-spherical AlN/PDMS composites and 80 wt% APP-modified spherical AlN/PDMS composites were 1.60 times and 1.48 times higher than unmodified AlN/PDMS composites, respectively. Semi-cured 80 wt% APP-modified spherical AlN/PDMS composites had a k of 4.19 W/mK and an enhancement of 1.4 times that compared with fully cured composites. Furthermore, semi-cured 80 wt% APP-modified spherical AlN/PDMS worked safely within the range of 200 °C and had a superior k.