Verbessertes Entwässerungsverhalten von elektronenbestrahlten Holzstoffen am Beispiel von Wasserrückhaltevermögen und spezifischer Oberfläche

Pre-treatment of wood chips and wood log discs with electron irradiation results in significant changes of the mechanical pulp properties. Interesting conclusions for the application of such mechanical pulps can be drawn not only from the energy savings during refining (TMP) and grinding (SGW), but also from the resulting pulp properties such as fibre morphology and drainability. The suitability for a partial application in newsprint has already been shown in mill-scale1, and now, the property changes are focused more in detail. The varied morphology of mechanical pulps after raw material irradiation appears i.a. in shorter and more straight fibres with reduced cross-sectional dimensions and thus, with a lower coarseness. In the light microscope, smoother and more closed fibre surfaces could be observed. The swelling ability and the ability to bond water onto the fibre surface, respectively, that can be removed mechanically, decreased. Subsequently, a better drainability for these pulps was measured by water retention value and hydrodynamic specific surface area. The development of strength properties for handsheets was discussed based on the results from fiber morphology and drainability leading to the conclusion that mechanical pulps after electron irradiation can be produced more energy-efficient with good drainability but some strength decay.