Expanded graphite reinforced flexible microencapsulated phase change composites for efficient thermal management

Problems of leakage and low thermal conductivity of phase change materials (PCMs) limit their applications to practical thermal management systems. To overcome these obstacles, a series of flexible composite phase change materials (FCPCMs) of silicone rubber (SR)/paraffin@melamine-formaldehyde resin (Pa@MF) microcapsules/expanded graphite (EG) were prepared in this study. The prepared FCPCMs showed significantly improved normal thermal conductivity with a value of 2.357 W/(m·K) at a microcapsule mass fraction of 25 % and EG mass fraction of 20 % (FCPCM-20), which are 1339 % higher than that of pure SR. Furthermore, the composite has excellent thermal buffering and heat dissipation capability. In the chip thermal management test, FCPCM-20 can significantly reduce the operating temperature of the chip, which is 66.77 % lower than that of SR. By comparing with the sample that only has added an equal amount of EG, the temperature reduction at heating powers of 10 W, 15 W and 20 W reached 19.80 %, 22.79 %, and 23.53 %, respectively. The results demonstrate that the fabricated composites possess superior thermal buffering and thermal regulation performance, showcasing great potential of applications to chip thermal management such as heat dissipation.