Study on the Morphology of Paper-making Hemps. III

The Effect of Beating on the Structure of Fibre Walls and Hand-sheets from Non-wood Fibres

Abstract

Fibres of flax waste and kenaf bark were studied on their morphological changes during pulping and beating by means of scanning electron microscopy and specific surface measurement. Following results were obtained.
1) Flax fibres were frozen smashed in liquid nitrogen and gently delignified with chloriteacetic acid solutions. Thus middle lamellae and the primary walls were removed and disappeared, then the secondary walls with fibrils of about 10° inclined S helics were exposed. These fibrils were split into fibril bundles of one to several μm width parallel to the fibrilar angle. Moreover, the secondary walls were delaminated easily to separate.
2) Kenaf fibres, which were treated as flax fibres, exposed the secondary walls with fibrils of Z helics of about 10°. However, no fibril bundle was observed. This can be considered that a cohesion force between fibrils of kenaf fibres is stronger than that of flax fibres.
3) At the same freeness level, specific surface area of handsheet from flax fibres was larger than that of kenaf. This is because flax fibre is more subjected to the external fibrillation, so fibril bundles and fibrils are easily separated from a parent fibre to form a closed sheet structure.
On the other hand, kenaf fibres are least changed macroscopically during pulping and beating, so fibres are the main geometrical component of the sheet strcture.