Effects of chain structure on damping property and local dynamics of phenyl silicone rubber: Insights from experiment and molecular simulation

Abstract

The dynamic mechanical property of silicone rubbers with different phenyl units and phenyl contents were comprehensively investigated by means of experiments combined with molecular dynamics (MD) simulation. Experimentally, the results indicate that the phenyl units are randomly distributed in the polymer chains and the damping capacity is considerably improved with the augment of phenyl contents. Compared with methylphenyl units, diphenyl units endow the silicone rubber with enhanced mechanical stability, which leads to a wider glass transition region and effective damping temperature range. Furthermore, the MD simulation reveals the equilibrium structures and local dynamics by monitoring the changes of molecular interactions, bond rotation, conformational transition and molecular diffusion during the cooling process, which correlates the dynamic mechanical response to the molecular relaxation behavior. This work provides a deeper insight into the relationship among the composition, microstructure and damping property, which may promote theoretical predictions and scientific basis for the designs of silicone rubber with desired performances.

Keywords

• Silicone rubber
• Damping property
• Molecular dynamics simulation
• Local dynamics
• Sequence distribution