Microscopical study on the effects of partial removal of xylan on the swelling properties of birch kraft pulp fibres

摘要

A study was made of the effect of xylan removal on the surface structure and swelling properties of unbleached and bleached birch kraft pulp fibres. Wetting experiments were undertaken using an environmental scanning electron microscope (ESEM) and a confocal laser scanning microscope (CLSM) in order to examine the effects of partial removal of xylan on the swelling properties of fibres. The dimensional changes in fully saturated samples were monitored as they dried. The dry fibres were then rewetted and swelling behaviour observed. Xylan removal produced no observable changes in fibre surface structure. However, the wetting experiments showed that fibre swelling properties were severely affected by the partial removal of xylan; both unbleached and bleached pulp fibres with reduced xylan content collapsed on drying and swelled very little on rewetting as compared with the corresponding intact pulp fibres. In practise this might result to a need of additional beating in order to maintain desired paper properties.