Recyclable Solid‐solid Phase Change Polymer‐based Composites With High Latent Heat and Ultrahigh Thermal Conductivity via Dynamic Internal‐catalyzed Esterification and Vertically Oriented Conductive Pathway

Abstract At present, the internal design of electronic devices tends to be integrated and miniaturized, and there is an urgent demand for composites with both high latent heat and high thermal conductivity (TC) to realize rapid heat dissipation. Herein, a simple and efficient strategy is proposed to fabricate solid‐solid phase change materials (SSPCMs) based on thermally conductive composites with high latent heat, ultrahigh TC, and reprocessability. The SSPCMs (MP) are synthesized by internal‐catalyzed esterification between styrene‐maleic anhydride copolymer (SMA) and polyethylene glycol (PEG), and then the composites (MP‐OCF) are obtained by filling the reaction in vertically oriented carbon fiber arrays (OCF). The resulting MP attains a phase transition enthalpy of 151.1 J g⁻¹, in which transesterification occurs internally at 120 °C for reprocessability. The composite MP1‐2‐OCF possesses an ultrahigh TC of 128.12 W m⁻¹ K⁻¹ and high phase transition enthalpy of 116.3 J g⁻¹ within 28.62 vol% CFs, which can be reprocessed at 120 °C and restored to its original state and property. Furthermore, the composites MP‐OCF have a good application in heat dissipation and solar energy storage. This work provides a facile method for the preparation of thermally conductive composites that can be widely applied in thermal management.