Fracture Toughness of Hydrothermally Aged Epoxy Systems with Different Crosslink Density
- Autori: Alessi, S; Di Filippo, M; Pitarresi, G; Scafidi, M; Toscano, A
- Anno di pubblicazione: 2015
- Tipologia: Articolo in rivista (Articolo in rivista)
- Parole Chiave: Fracture Toughness; Hydrothermal Aging; Image Analysis; Photoelastic Stress Analysis; Swelling Stresses; Thermosetting Resin; Engineering (all)
- OA Link: http://hdl.handle.net/10447/149963
Abstract
The present work investigates the fracture toughness behaviour of Single Edge Notched Bending (SENB) samples of epoxy systems subject to water uptake aging. Two epoxy systems with a significantly different Glass Transition Temperature, Tg, are in particular considered: a typical commercial non-aeronautical grade resin matrix for composite applications, reaching aTgof 90°C, and a DGEBA+DDS epoxy system achieving a Tg of 230°C.The materials have been conditioned by hydrothermal aging in a thermal bath at the temperature of 50°C. TransmissionPhotoelastic Stress Analysisis carried outon SENB samples during water aging, monitoring the presence and evolution of swelling stresses. The KIC Fracture toughness is measured and correlated with the internal stress field, with the water diffusion kinetics evaluated by gravimetric tests, and with the data from DMTA analyses. Results have highlighted significant differences in the fracture behaviour ofthe two epoxy systems.