Core-shell Co-C@CNT engineered to enable concurrent thermal conductivity and microwave absorption for Poly(4, 4′-dihydroxybiphenyl isophthalate)

As electronic devices trend toward miniaturization and higher performance, effective heat dissipation and electromagnetic interference suppression have become critical challenges. The development of thermally conductive/microwave absorption polymer composites is urgently required. In this work, carbon nanotube (CNT) is grown in-situ on Co-C surface through pyrolysis of thermally robust, large-particle zeolitic imidazolate framework-67 (ZIF-67) and melamine (MF). The obtained core-shell Co-C@CNT is blended with a self-synthesized side-chain poly(4, 4′-dihydroxybiphenyl isophthalate) (S-PDI) to prepare Co-C@CNT/S-PDI composites using “solution coating-stacking-hot pressing” process. When the MF:ZIF-67 mass ratio is 1.5:1, an optimal core-shell morphology and the highest thermal conductivity of Co-C@CNT are achieved. 25 wt% Co-C@CNT/S-PDI composites exhibit thermal conductivity of 0.84 W/(m·K), which is 133.3% higher than that of S-PDI (0.36 W/(m·K)). Moreover, corresponding minimum reflection loss, elasticity modulus and heat resistance index reach −53.8 dB (8.08 GHz), 5.3 GPa and 185.0 °C, respectively.