Tailoring silicone rubber properties through silica nanoparticle reinforcement: A molecular dynamics Perspective

YX Liu and KW Huang and K Yang and QZ Han and SL Zhong and ZM Dang, COMPUTATIONAL MATERIALS SCIENCE, 258, 114097 (2025).

DOI: 10.1016/j.commatsci.2025.114097

Silicone rubber is extensively employed in high-voltage power equipment, such as cable joints, owing to its excellent insulating properties and processability. The incorporation of silica (SiO2) nanoparticles has been shown to significantly enhance both the mechanical and dielectric performance of silicone rubber composites. Establishing robust structure-property relationships across multiple scales is therefore of critical importance for the rational design of such materials. In this study, a molecular dynamics (MD) simulation framework was developed to systematically investigate the influence of molecular chain architecture, crosslinking networks, and nanoparticle surface modifications on the physicochemical, processing, and electrical properties of silicone rubber nanocomposites. The simulation results demonstrate that silicone rubber with a denser crosslinking network exhibits more pronounced mechanical reinforcement upon the addition of nano-silica. For instance, with 20 wt% nano-silica, the mechanical strength of a system with a chain length of 33 and 23 active crosslinking sites is over 1.5 times higher than that of a system with a chain length of 11 and 8 active sites. However, excessive nanoparticle aggregation detrimentally affects the dielectric performance. Optimal dielectric properties are achieved when the effective diameter of dispersed or aggregated silica nanoparticles is approximately 14 angstrom, corresponding to a free volume fraction of similar to 36 % and a relative dielectric constant of similar to 7. These findings offer valuable guidance for the design and optimization of high-performance silicone rubber composites in high-voltage insulation applications.

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