Influence of Fibre Morphology and Processing on the Softwood Sulphate Pulp Fibre and Paper Properties

摘要

Pulp is not a bulk product any more. Each end-product sets its own pulp fiber requirements. In order to fulfil customer needs, every pulp maker must understand how to produce softwood sulfate pulp fibers with specific properties (fiber strength, flexibility and bonding potential). However, it is almost impossible to know which factors are responsible for good or poor paper properties, if the papermaking potential of pulp fibers is characterized in the conventional way by testing laboratory hand sheets. The research reviewed in this paper examines how wood fiber properties (morphological, fine-structural and chemical) and specific cooking parameters affect the papermaking potential of sulfate pulp fibers and their development in beating. In addition, a method for characterization of pulp quality (papermaking potential) through pulp fiber and network properties was developed and tested. In this work, pulp fiber properties comprise cell wall thickness (coarseness), length-weighted fiber length and fines, intrinsic fiber strength, conformability (wet fiber) flexibility and collapsibility) and degree of external fibrillation. Network properties are defined as bonding potential of fibers (bonding strength and bonded area) and network structure (geometrical properties). The results clearly showed that the papermaking potential of softwood sulfate pulp fibers depends on the morphological properties of wood fibers, especially on cell wall thickness. Although low alkali charge improves fibers flexibility and high sulfidity prevents fiber strength reduction in cooking, it is not possible by means of such process parameters to compensate for the pulp quality variations caused by variations in raw material.