Open this publication in new window or tab >>2013 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]
Improved understanding regarding how to optimise the degree of swelling in the wood fibre wall may be a way to reduce the energy demand in the refining process. The forces necessary to achieve fibrillation (internal as well as external) are greatly influenced by the swelling properties of the fibre wall. The degree and position of swelling is also the main cause to where in the wood matrix the fibre separation will take place. Refining of wood chips in different state of swelling will result in mechanical pulp fibres with different optical and mechanical properties.
The typical parameters that influence the wood fibres’ ability to swell are temperature, pH, ionic form, amount of charged groups and ionic strength. Water retention value is one way to measure the pulp´s capacity to retain water after centrifugation and is strongly correlated to the swelling ability of wood fibres.
A blowline-sample of Norway spruce thermomechanical pulp (TMP) taken out directly after the chip-refining step was used as reference material for this study. The sample was treated with sodium sulphite under different conditions to introduce a range of very low to very high degrees of sulphonic acid groups in the cell walls. In a similar way alkaline hydrogen peroxide was used to introduce a range of very low to very high degrees of carboxylic acid groups. Each sample was then ion-exchanged into proton, sodium, calcium and aluminium form.
The effect of the amount of sulphonic and carboxylic acid groups in combination with the effect of counter ion, on the swelling capacity of mechanical pulp fibres was investigated. In addition, all samples were measured in a temperature interval between 25°C and 95°C to monitor changes in the softening temperature due to lignin structure modifications.
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-20636 (URN)
Conference
8th International Fundamental Mechanical Pulp Research Seminar (IFMPRS), Åre, Sweden, Jan 29-31, 2013
Projects
Maximized Fibre Wall Swelling in TMP & CTMP Refining
2013-12-112013-12-112013-12-12Bibliographically approved