Nanocellulose from fractionated sulfite wood pulp

Fine fibre fractions in wood pulp may contribute to advantageous paper properties, but in some instances their removal from pulp may be beneficial to the production process of certain paper grades. In order to study the suitability of fine fibre fractions for the production of nanocellulose as an alternative use option, sulfite pulp was fractionated and homogenised, and cellulose nanopapers were produced. Characterisation revealed that fine fibre fractions were more easily homogenised than long fibres. Aqueous suspensions of nanocellulose produced from fines showed remarkably reduced viscosity compared to nanocellulose derived from long fibres. Nanopapers produced from all nanocellulose variants showed roughly similar mechanical performance. Only nanopaper produced from primary fines-derived nanocellulose deviated in that it showed a comparably high modulus of elasticity at a low strain at failure. Overall, fine fibre fractions separated from wood pulp were found to be highly suitable for nanocellulose production.