Cellulose and lignocellulose nanofibril suspensions and films: A comparison

A comparative study on the morphology and physico-mechanical properties of cellulose nanofibrils (CNF) and lignocellulose nanofibrils (LCNF) produced using a pilot-scale ultra-refining facility in the form of slurries and films was conducted. Suspensions and films of CNF and LCNF at different fines contents from 50% to 100% were prepared from bleached kraft pulp and old corrugated container (OCC) feedstock, respectively. We showed that the effect of film density on mechanical properties of CNF and LCNF films can outweigh the effect of fines content (or degree of fibrillation) and consequently an equally strong and stiff film can be produced from lower grades of CNF or LCNF at higher densities. After density normalization, particle size was found to be the main determining factor. Finally we conclude that a CNF or LCNF suspension with 70 % fines will yield films as strong and stiff as the materials with 100 % fines providing an opportunity for cost reduction.