Effect of inter-fibre bonding on the fracture of fibrous networks with strong interactions

The mechanical response of cellulose nanopaper composites is investigated using a three-dimensional (3D) finite element fibrous network model with focus on the effect of inter-fibre bonds. It is found that the Young's modulus and strength, for fixed fibre properties, are mainly controlled by the density and strength of the inter-fibre bonds. An increase of the inter-fibre bond density and inter-fibre bond strength results in an increase of both the Young's modulus and strength of the fibrous network materials. The fracture energy of the inter-fibre bonds has a minor effect on the mechanical properties of the cellulose nanopapers. The inter-fibre bond properties and density have a minor effect on the strain to failure of the cellulose nanopaper. The effect of the fibre properties, through the ratio of fibre tensile strength to fibre Young's modulus, has also a significant impact on mechanical response of the network including the strain to failure.