The increasing demand of thermal management materials consumes a large amount of petrochemical and inorganic mineral resources. It is essential to develop a kind of highly thermally conductive composite with realizable closed-loop recycling. Based on the covalent adaptable networks (CANs), which are filled with boron nitride (BN) and liquid metal (LM), recyclable biphenyl epoxy composites (LEP/BN/LM) with directional controllable thermal conductivity have been prepared in this study. The induced dual-aligned liquid metal and boron nitride in the preparative film composites is obtained using repeated pressing-rolling technique. The bulk composites are fabricated by film-stacking method, relying on self-healing via interesterification between each layer. By altering the stacking mode, high thermal conductivity can be obtained in the desired direction, which realizes the directional controllable high thermal conductivity. The result shows that a high thermal conductivity of 5.41 W m⁻¹ K⁻¹ can be achieved in the predominant direction of the LEP composite. The experiment indicates that the prepared composites have excellent thermal management ability. It also confirms that the filler and the organic compounds can be completely separated by mild chemical routes, which can be reused further.

Phase change materials (PCMs) exhibit significant potential for overcoming the issues related to thermal energy storage and management. However, they have faced persistent challenges in applications due to liquid leakage and solid rigidity. Novel tough and sustainable solid–solid phase change materials (SSPCMs) have been achieved using the designed carboxyl-epoxy group reactive system, which forms a reversible vitrimeric structure after crosslinking. It is demonstrated that the networks overcome the limitations of liquid leakage and solid rigidity, showing excellent phase stability after being heated for 5 hours with a tensile strength of 13.5 MPa and an elongation at break of 45%. The highest phase transition enthalpy of the prepared SSPCMs is 92.01 J g⁻¹. The reversible phase transition of polyethylene glycol (PEG) segments locked within the networks enables excellent smart shape memory features. Notably, the networks can undergo rearrangement through interesterification, thereby acquiring recyclability and self-healing properties. Additionally, the thermal conductivity of the matrix is enhanced through the addition of BN. It is further demonstrated that the thermally conductive PCMs retain high toughness, recyclability and shape memory features, while simultaneously exhibiting potential thermal management capabilities.