LAUSR

Abstract Fine fibres (fines) occur at various stages of the papermaking process. The high specific surface of fines may be of special interest in applications beyond papermaking. In the present study, foamy water suspensions of fines were freeze-dried, and in this way their porous structure was maintained. The density and porosity of these foams could be governed by varying the water content of the suspensions. The obtained matrices were highly hydrophobic because of the sizing applied during the papermaking process. Consequently, a high oil sorption capacity of the fines was observed. Up to a porosity of 98%, more than 80% of the overall volume of the foam-like material could be soaked with liquid. At higher porosities, the absorbed volume decreased. Mechanical reinforcement of the foams with poly(methyl methacrylate) (PMMA) as accomplished by dip-coating had no negative impact on the sorption behaviour. However, the performance of reinforced samples suffered from strong shrinkage upon drying, especially for high porosity matrices.