High Thermal Conductivity and Latent Heat Phase Change Materials Enabled by One-Step Reactive Grafting and a 3D Quasi-Hyperbolic Thermal Network

With the rapid advancement of big data, cloud computing, and artificial intelligence, the demand for efficient thermal management in electronic devices has become increasingly critical. Phase change materials (PCMs) are considered ideal candidates; however, traditional PCMs suffer from issues such as leakage during the melting phase and low thermal conductivity (TC). In this study, a highly reactive one-step epoxy–carboxylic acid grafting method was employed to graft stearic acid (SA) onto the backbone of polyethylene-co-methyl acrylate-co-glycidyl methacrylate (PEMAGMA). This process enables the fabrication of grafted solid–solid phase change materials (SS-PCMs) with high latent heat (155.4 J/g) and low leakage (1.85%) within a relatively short preparation time of 6 h. Then, the SP was combined with an electrochemically expanded graphite (EEG) framework to enhance TC. The final composite exhibited a high TC of 17.7 W/(m·K), high latent heat (94.53 J/g), and excellent antileakage performance (0.07%). The LED heat dissipation experiment demonstrated the practical applicability of the SP/EEG composites, reducing the LED’s maximum operating temperature by 15 °C compared to commercial thermal interface materials (TIMs), thereby enhancing thermal management efficiency. This study provides a simple and efficient strategy for synthesizing high-performance composites for advanced thermal management applications.