Interlaminar fracture toughness and fatigue delamination of carbon nanofibers modified polyester/ glass fiber laminates

Laminated composites are most vulnerable to delamination due to a weak matrix/ reinforcement interface. This research presents the effects of modifying unsaturated polyester resin with carbon nanofibers (CNFs) on the composites' response to delamination and fatigue. Several composites were manufactured from glass fiber and neat resin, 0.5wt%CNFs, or 1.0wt% CNFs modified resin solutions. An artificial crack was introduced between laminates of the glass fiber during composite manufacturing. Mode-I interlaminar fracture toughness and Mode-I fatigue delamination growth onset were studied. Results revealed an increased ability of CNFs modified resin composites to sustain higher loads and provide structural improvements to the composites. The decrease in the interlaminar fracture toughness in the modified resin solutions is attributed to the interaction of CNFs with the curing compound and interaction with the resin. Under fatigue testing, delamination length propagates shorter distances for the same number of cycles in CNFs modified resins than in neat resin.