Enhancement of the interlaminar fracture toughness and damping properties of carbon fiber reinforced composites using cellulose nanofiber interleaves

Cellulose nanofibers (CNFs), with excellent mechanical properties, could be obtained from plant fibers and prepared by the combined mechanical and chemical methods. Waterborne epoxy was used to reduce the hydrophilicity of CNFs before the CNFs films were prepared by freeze-drying and inserted between layers of carbon fiber reinforced polymer composites (CFRPs). The effects of CNFs content on the interlaminar fracture toughness and damping properties of CFRPs were investigated, and the lay-up sequences of CNFs interleaves on the loss factors of CFRPs were also examined. The results reveal that by the addition of 0.075 wt% and 0.05 wt% CNFs, the mode I and mode II interlaminar fracture toughness of CFRPs were improved by 22% and 25%, respectively. With the addition of 0.25 wt% CNFs, the loss factor of CFRPs was increased by 31%. However, the tensile and flexural properties of interleaved CFRP were only slightly decreased.