A comparative study of viscoelastic characteristics in polymer composite with respect to the damping performance and structural behavior

This study systematically investigates the viscoelastic characteristics and damping performance of polymer composites, examining the interplay between filler morphology, matrix-filler interactions, and structural behavior. The purpose is to understand and predict how different fillers influence key viscoelastic properties to enable tailored composite design. Methods and Key Findings: Dynamic mechanical analysis (DMA) and forced vibration tests were used to characterize temperature- and frequency-dependent viscoelastic properties, including storage modulus (E′), loss modulus (E′′), and damping factor (tanδ). Key results demonstrate distinct effects: Spherical calcium carbonate increased stiffness (E′) by 45% at 15 wt% loading but restricted damping (tan δ) due to agglomeration-induced stress concentrations. In contrast, core-shell rubber particles increased tan δ by 280% through interfacial slip, achieving a damping ratio (ζ) of 0.052 (2.8 times higher than neat epoxy). Nanoclay composites exhibited frequency-dependent damping anisotropy from processing alignment. Hybrid filler systems showed synergistic damping effects within the 10–50 Hz range. Optimal performance occurred at 5 wt% Al₂O₃, balancing moderate stiffness (E′ = 1.5 GPa) with peak damping (tan δ = 0.82). Microstructural analyses (SEM/AFM) correlated maximized interfacial friction and damping with an agglomerate area fraction <10%. A validated multi-scale computational model (<7% error) successfully bridged nanoscale mechanisms to macroscale performance. Significance and Applications: This work provides a predictive framework for designing next-generation composites. It enables tailored material design—prioritizing damping for applications like automotive NVH systems or stiffness for aerospace components—advancing fundamental knowledge of composite viscoelasticity and offering practical strategies for industrial vibration mitigation.