Synthesis of Guaiacol-Based Phenolic Epoxy Resins and Their Thermal Conductivity Study

With the development of electronic devices toward higher integration, miniaturization, and higher power density, epoxy molding compounds (EMCs) face higher standards in terms of fluidity, low-temperature curing, and thermal management characteristics. To address these challenges, the development of EMCs with improved thermal conductivity and processing performance has become a core research topic. In recent years, biobased epoxy resins, due to their renewability and environmental benefits, have emerged as a potential alternative to petroleum-based resins. This study focuses on the design and synthesis of a phenolic resin (OMN) and epoxy resin (EOMN) using biobased guaiacol as the raw material, and optimizing its flowability, curing reactivity, and thermal stability by adjusting the molecular structure. The results show that the curing temperature and activation energy of the EOMN-OMN system are approximately 50 °C and 9.2 kJ/mol lower than those of the conventional petroleum-based epoxy resin, and the EOMN-OMN system exhibits superior flowability below 125 °C. Further enhancement of the system’s thermal conductivity was achieved by incorporating four thermally conductive fillers, namely boron nitride (BN), hexagonal aluminum nitride, silicon carbide, and cubic silicon nitride, with the BN-EOMN-OMN composite exhibiting the highest thermal conductivity of 0.340 W/(m·K), which was 215% of that of the pure resin. Moreover, BN was found to significantly improve the hardness and Young’s modulus of the EOMN-OMN composite. This study provides useful insights for the design of biobased resin systems with potential relevance to EMC-related applications.