The Strength of Cellulose Nanofibre Sheets

The sheet strength of cellulose nanofibre sheets is of interest in a wide variety of applications. This study looks at understanding the mechanisms of nanofibre sheet strength by using up to 80% silica nanoparticles as a spacer between the nanoparticles. The silica nanoparticles are largely inert and by varying the amount of silica nanoparticles we can vary the fibre density of the network. The cellulose nanofibre network does not act as a conventional wood fibre network. The data show that the nanofibers are forming a non-woven network with highly efficient stress transfer between the fibres, requiring relatively few fibre-fibre bonds to efficiently transfer load through the network, thus tensile strength was essentially independent of fibre density, while stiffness went up with reduced network density and strain at break went down. These changes may be explained by the nanoparticles physically limiting rearrangement of the fibre network to accommodate the load applied to the network. The results will then be discussed in terms of theories of paper strength and compared with data from the literature.