Modulating impact resistance of flax epoxy composites with thermoplastic interfacial toughening
Farzin Javanshour, Alexandros Prapavesis, T. Pärnänen, Olli Orell, Maria Clara Lessa Belone, Rama K. Layek, Mikko Kanerva, Pasi Kallio, Aart Willem Van Vuure, Essi Sarlin
Abstract
The application of natural flax fibre/epoxy composites is growing in the automotive sector due to their good stiffness and damping properties. However, the impact damage resistance of flax/epoxy composites is limited due to the brittle nature of both epoxy and flax fibres and strong fibre/matrix adhesion. Here, biobased thermoplastic cellulose acetate (CA) is deployed as a fibre treatment to alter the damage development of flax/epoxy composites subjected to low-velocity impact. The perforation threshold energy and the perforation energy of unmodified cross-ply composites increased respectively by 66% and 42% with CA-treated flax fibres. The CA-modification modestly decreased the transverse tensile strength and in-plane tensile shear strength of the composites. However, it altered the brittle nature of flax/epoxy laminates in quasi-static tests into ductile failure with clearly increased fibre–matrix debonding.