Rheology of pulp fibre suspensions: A critical review

This paper reviews past studies on the measurement of rheological properties of pulp fibre suspensions. Such suspensions are complex fluids important in the manufacture of many pulp-fibre based products, such as communication papers, hygiene products, packaging, as well as other fibre-based materials. Pulp suspensions play a role in other biomass conversion processes as well. This review focuses on key properties of fibre suspensions, such as regimes of behaviour based on inter-fibre contact, apparent yield stress, apparent viscosity, and viscoelasticity. Difficulties encountered in measurement of these properties due to flow regime changes, heterogeneous mass distribution, and formation of depletion layers at solid boundaries is discussed and methods to overcome them are reviewed.