Dependence of Sheet Properties on Formation and Forming Variables – Prepared Contribution

Abstract

As with all papermaking characteristics, the interpretation of observations on the behaviour of wood fibre networks is made more difficult by the heterogeneous nature of the fibres in a given pulp. The fractionation of fibres by length indeed makes analysis of the phenomena easier, but the flexibilities of fibres of equal lengths in the same pulp are very varied and it is well known that this factor has a great deal to do with wet web formation and its strengthening during drying. We were able to compare, for example, the development during slow drying of the strength of wet webs made of fibres from the same unbeaten pulp, fibres of the same length, but of different flexibility and wall thickness. The method for sorting pulp fibres by flexibility is a simple one that uses the differences in behaviour of these fibres in the networks while in motion. We shall say a few words about this method later, as we think it can make useful contributions in the field of papermaking fibrous networks.