High-frequency vibration damping properties of epoxy resins and their powder composites

The research on vibration damping of epoxy resins holds great potential, as it addressesthe ongoing risks posed by vibration environments to the maintainability and suitabilityof materials in diverse applications. The addition of fillers emerges as a key methodto transform epoxy resin properties, offering potential benefitsts.This research focused on zirconium tungstate, a ceramic powder with a negativethermal expansion coefficient. It was meticulously added to three epoxy resins, each basedon a bisphenol A diglycidyl ether epoxy and three different amine hardeners. The zirconiumtungstate was introduced in varying percentages (0.1, 0.5, and 1 wt.%) to the epoxies,and the effects on the epoxies' thermal expansion, glass transition, and vibration dampingproperties were rigorously studied in both low-frequency and high-frequency domains, up to2KHz.The glass transition temperature of the epoxies showed a decreasing trend with increasingfiller percentage, which is a typical finding when adding fillers to epoxy resins. Thethermal expansion coefficient (CTE) provided interesting results. There are two CTEs forthe epoxy resins. One below and one above the glass transition (Tg), the CTE below Tghighlight a suppression of the epoxies CTE, however above Tg, the CTE increased withincreasing filler content. Vibration damping in the low and high-frequency domains posednew challenges initially through the use of time-temperature superposition supported byKramers-Kronig relations to validate the shift curves, which saw the shift factors relate tothe Williams-Landen-Ferry model. A high-frequency set-up was created to explore the epoxyresin vibration responses up to 2KHz, in line with ASTM E756-05. The storage modulusincreased with increasing filler content at room temperature. Overall, this thesis exploresthe relation of the zirconium tungstate filler to the epoxy resin focusing on the vibrationdamping properties.