On the Effect of Recycling on Cross-Sectional Shapes and Dimensions of Sulphate Pulp Fibres, 1997 Recycling Symposium Proceedings

A prerequisite for the interfibre bonding needed in strong papers is that fibres should be flexible in order to conform and come in close contact during forming and consolidation of the sheet. Fibre flexibility depend on fibre wall thickness; fibre width and fibre collapsibility, as well as the elastic and plastic properties of the fibre wall.

The purpose of this study was to investigate the effect of recycling and beating on cross-sectional shapes and dimensions of chemical pulp fibres. The distributions and/or average values of fibre wall thickness, fibre wail area, lumen area, fibre width, inner and outer perimeter, degree of collapse and cross-sectional shape are reported and discussed.

In order to measure cross-sectional fibre dimensions before shrinkage due to drying, freeze dried fibre samples from virgin as well as unbeaten and beaten recycled chemical pulp fibres with either hydrogen or sodium as counter-ions of acidic groups were investigated using SEM and image analysis techniques....