A study on the thermodynamic performance of nano-silicide filled epoxy resin composite materials

As the performance requirements for epoxy resin (EP) in ultra-high voltage systems become more stringent, electrical breakdowns remain a recurrent issue. Studies have shown that the incorporation of silicide nanomaterials (SiO₂, Si₃N₄, and 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. While most studies rely on conventional experimental approaches, molecular simulation techniques offer a promising alternative to predict the properties of EP composites and guide experimental design, thereby optimizing resource utilization. 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^-1. 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 (T_g) 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 composite shows the best thermodynamic performance. Composites with 0.5% SiO₂, Si₃N₄, SiC, and 1.5% SiC are experimentally prepared, and their thermodynamic properties are 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 T_g is enhanced by 1.6% to 4.7%, and the thermal conductivity ranges from 0.125 to 0.147 W m^-1 K^-1, which is lower than that of EP (0.164 W m^-1 K^-1). Compared to 0.5%-EP/SiC, the 1.5%-EP/SiC composite exhibits superior thermodynamic performance, with a 35.0% increase in the storage modulus, a 9.8% increase in T_g, and a thermal conductivity of 0.154 W m^-1 K^-1. The results of this study provide valuable insights for improving the thermodynamic properties of EP.