Enhanced the thermal conductivity of PDMS composites under cyclic compression or thermal-oxidative aging through incorporating BN and SiC hybrid fillers

Polydimethylsiloxane (PDMS) is an important thermal interface materials in electronic packaging industry with the aid of incorporating thermal conductive fillers. However, the thermal conductivity of PDMS composites is easily affected by outside thermal aging or force field. Herein, hybrid fillers containing boron nitride (BN) and silicon carbide (SiC) or silicon carbide nanowires (SiCNW) were used to construct stable thermal conductive pathways in PDMS matrix under cyclic compression or thermal-oxidative aging conditions. The optimum weight ratio of BN to SiC or SiCNW is 9:1 to obtain high thermal conductivity in PDMS. The thermal conductivity of BN 9 /SiC 1 /PDMS and BN 9 /SiCNW 1 /PDMS composites are slightly decreased by 4.50 and 4.20%, respectively after 64 h of thermal-oxidative aging when the mass ratio of BN to SiC or SiCNW is 9:1. Higher load bearing capacity of BN 9 /SiCNW 1 /PDMS composite can guarantee the good stability of thermal conductivity under cyclic compression. The thermal conductivity of BN 9 /SiCNW 1 /PDMS composite material is increased from 0.96 to 1.12 W m −1  K −1 , with a growth rate of 16.60% after 30 cycles of 1000 N compression, while the thermal conductivity of the BN/PDMS composite is decreased under the same compression conditions. Mechanisms of the cyclic compression effect on the variation of structure and thermal conductivity were proposed. This indicates that BN and SiC hybrid filled polymer composites could maintain high thermal conductivity under thermal-oxidative aging or cyclic compression.