Estimating the transverse dimensions of cellulose fibres in wood and paper using 2D and 3D microscopy techniques

We describe a duo of experimental methods for determining the transverse dimensions of individual wood fibres using 2D optical microscopy and 3D X-ray tomography. These non-invasive optical sectioning methods, in conjunction with segmentation through image analysis, enables in situ identification of individual fibres in a paper sheet. The relationship between local fibre dimensions, i.e. diameter and fibre wall thickness, are established for kraft (NBSK) pulp fibres and compared to values obtained from wood. For the first time, we propose a criterion for transverse fibre collapse during the papermaking process that is based on both fibre diameter and wall thickness.Graphical abstract