(Y.L. Yao). Available online at www.sciencedirect.com

; ac e 5 This letter discusses the effect of bonding energy on the delamination resistance of laminate composites using a ductile interleaf. The mechanism and methods for interleaf toughening are reviewed and the improvement in delamination resistance discussed. The bonding energy between the ductile interleaf polymer and the fibers as well as between the ductile interleaf polymer and the brittle matrix polymer is shown to be a limiting factor in the interleaf toughening of epoxy based laminates. A dual bonding approach, that is, melt bonding and ing and material costs of any matrix. Laminate PMC fab- (called ply drop-offs shown in Figure 1a) between the root ture surface (Figure 1). Inter-laminar toughening is of crit-ical importance in composite applications with demanding geometric requirements such as tapers, free edges, and holes