Our latest range of thermoplastic veils have been developed specifically to increase the interlaminar fracture toughness of a composite.

An improvement of up to 400% in the Mode-I and Mode-II fracture toughness is achieved by interleaving these lightweight thermoplastic veils between reinforcement plies and infusing the structure with resin.

Fibre reinforced composites, comprising of a layup of carbon reinforcement fabrics infused with epoxy resin, can exhibit low interlaminar fracture toughness. In service these composite materials can be prone to interlaminar failure under both Mode-I and Mode-II. The presence of interlaminar damage can be very detrimental to the delamination fatigue properties of a fibre reinforced composite and ultimately compromise the mechanical performance of the structure.

TFP has developed an extensive range of thermoplastic veils which deliver a proven increase in the interlaminar fracture toughness of a composite, these include; Polyimide, PEEK, PPS, PEI and Polyester. The improvement is achieved by interleaving these lightweight thermoplastic veils between the reinforcement plies and then infusing the structure with resin.

Recent studies1 have measured the effect of interleaving various veil types, relative to a control, for both Mode-I and Mode-II testing. The data indicates that the use of TFP’s thermoplastic veils can engineer a significant improvement in the Mode-I and particularly Mode-II fracture toughness, for the latter an improvement of up to 350% & 430% (for initiation & propagation respectively) can be achieved.

1V.A. Ramirez, P.J. Hogg, W.W. Sampson - The influence of the nonwoven veil architectures on interlaminar fracture toughness of interleaved composites, Composites Science and Technology 110 (2015) 103-110.