Ethylene vinyl acetate (EVA) cross-linked with dicumyl peroxide (DCP): Studies of viscoelastic and damping properties

Uncontrolled vibrations reduce safety, durability, efficiency, comfort, and overall performance in engineering systems; therefore, effective vibration damping is essential. Viscoelastic materials play a crucial role in vibration damping due to their ability to dissipate energy, their tunable properties, and their broad range of applications. Ethylene vinyl acetate (EVA), a thermoplastic copolymer with inherent viscoelastic properties, is widely used in vibration-damping applications. However, its damping capacity can be further improved through cross-linking. This study investigates the damping performance of ethylene vinyl acetate with 18 wt%. vinyl acetate content (EVA-18) modified with 1–4 wt.% dicumyl peroxide (DCP) as a cross-linking agent. Mechanical properties were measured through tensile testing, and viscoelastic behaviour was characterized using Dynamic Mechanical Analysis (DMA). Damping performance was evaluated by Experimental Modal Analysis (EMA) in free-layer damping (FLD) and constrained-layer damping (CLD) configurations. Frequency-dependent system loss factors were predicted using B.C. Nakra’s analytical formulations were compared with EMA results. In FLD, the 1 wt.The DCP sample (EVA-1) showed the highest average loss factor (0.034), whereas in CLD, the unmodified EVA-0 exhibited the most significant loss factor (0.069). These results clarify how controlled DCP cross-linking modifies the viscoelastic and damping behaviour of EVA-18 and indicate its potential use in vibration control applications in automotive, aerospace, and structural engineering.