Study on Thermodynamic Performance of Nano-Silicide Filled Epoxy Resin Composite Materials

The performance requirements for epoxy resin (EP) used in ultra-high voltage power systems are becoming increasingly demanding, with frequent incidents of breakdowns occurring. Studies have shown that the incorporation of silicide nanomaterials (SiO2, Si3N4, SiC) into EP composites holds significant potential for enhancing thermodynamic properties. However, there is currently no clear consensus on the specific composition and proportion of these materials for improving the thermodynamic performance of EP. Furthermore, most studies rely on traditional experimental methods, while molecular simulation techniques can predict the properties of EP composites and guide experimental designs, thereby conserving resources. This study presents a molecular simulation of EP composites filled with SiO2, Si3N4, and SiC nanoparticles. The results indicate that the EP/SiC composite exhibits the most stable Mean Square Displacement (MSD), with more compact internal bonding and the highest interfacial binding energy of - 3026 kJ/mol. Compared to EP, the Young’s Modulus of Elasticity (E) of the three composites is improved by approximately 3.24% to 4.10%, the Glass Transition Temperature (Tg) is increased by approximately 10.75% to 12.80%, and the thermal conductivity is reduced by approximately 5.9% to 8.9%. Among the EP/SiO2, EP/Si3N4, and EP/SiC composites, the EP/SiC composite demonstrates superior overall thermodynamic properties. For the composites with 1.5% SiO2, Si3N4, and 1.0%, 1.5%, and 2.0% SiC (wt.%), the 1.5%-EP/SiC shows the best thermodynamic performance. Experimentally, composites with 0.5% SiO2, Si3N4, SiC, and 1.5% SiC were prepared, and their thermodynamic properties were evaluated. The experimental results show that the storage modulus of the different silicide-based composites shows minimal variation, increasing by approximately 11% compared to EP. The Tg is enhanced by 1.6% to 4.7%, and the thermal conductivity ranges from 0.125 to 0.147 W/m·K, which is lower than that of EP (0.164 W/m·K). Compared to 0.5%-EP/SiC, the 1.5%-EP/SiC composite exhibits superior thermodynamic performance, with a 35.0% increase in storage modulus, a 9.8% increase in Tg, and a thermal conductivity of 0.154 W/m·K. The results of this study provide valuable insights for improving the thermodynamic properties of EP.