Excellent thermal conductivity and electrical insulation in polyimide/graphene oxide/carbon nanotubes composites

Abstract

AbstractPolymer composites with heat resistance, good thermal conductivity, and insulation properties can meet the special needs of electronics and electrical appliances. In this work, graphene oxide (GO) and carbon nanotubes (CNTs) are coated by polydopamine (PDA). 4,4′‐diaminodiphenyl ether (ODA), pyromellitic dianhydride (PMDA), and 4,4′‐oxydiphthalic anhydride (ODPA) in‐situ polymerize to prepare poly(amide acid) (PAA) containing thermally conductive yet insulating fillers (PDA@GO, PDA@CNTs). As the concentration of fillers in PI composites increases, the thermal conductivity rises, but the insulation property decreases. Keeping the filler content constant and varying the ratio of PDA@GO and PDA@CNTs, the thermal conductivity increases and then decreases. When PDA@GO and PDA@CNTs have a mass ratio of 10:1, the significant synergistic effect affects the thermal conductivity. The PI/PG10C1–25 sample has a thermal conductivity of 1.46 W/(m·K), which is 6.9 times greater than the pure PI. Additionally, the volume resistivity, dielectric permittivity, and dielectric loss (100 kHz) of PI/PG10C1–25 are 2.8 × 1013 Ω cm, 5.4 and 0.28, respectively. The heat resistance of PI composites is almost the same as that of pure PI. Given these outstanding attributes, the developed PI composites offer vast applications in many fields.Highlights Synergistic PDA@GO and PDA@CNTs (10:1) optimize thermal conductivity. PI/PG10C1–25 achieves 6.9 times higher thermal conductivity than pure PI. Volume resistivity of PI/PG10C1–25 reaches 2.8 × 1013 Ω·cm. Dielectric permittivity of PI/PG10C1–25 reaches 5.4 at 100 kHz. Developed PI composites maintain excellent heat resistance.