| People | Locations | Statistics |
|---|---|---|
| Naji, M. |
| |
| Motta, Antonella |
| |
| Aletan, Dirar |
| |
| Mohamed, Tarek |
| |
| Ertürk, Emre |
| |
| Taccardi, Nicola |
| |
| Kononenko, Denys |
| |
| Petrov, R. H. | Madrid |
|
| Alshaaer, Mazen | Brussels |
|
| Bih, L. |
| |
| Casati, R. |
| |
| Muller, Hermance |
| |
| Kočí, Jan | Prague |
|
| Šuljagić, Marija |
| |
| Kalteremidou, Kalliopi-Artemi | Brussels |
|
| Azam, Siraj |
| |
| Ospanova, Alyiya |
| |
| Blanpain, Bart |
| |
| Ali, M. A. |
| |
| Popa, V. |
| |
| Rančić, M. |
| |
| Ollier, Nadège |
| |
| Azevedo, Nuno Monteiro |
| |
| Landes, Michael |
| |
| Rignanese, Gian-Marco |
|
Ketoja, Jukka A.
VTT Technical Research Centre of Finland
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (17/17 displayed)
- 2022Lignin interdiffusion - a mechanism behind improved wet strength
- 2022Utilizing and Valorizing Oat and Barley Straw as an Alternative Source of Lignocellulosic Fiberscitations
- 2022Utilizing and Valorizing Oat and Barley Straw as an Alternative Source of Lignocellulosic Fiberscitations
- 2021General mean-field theory to predict stress-compression behaviour of lightweight fibrous materials
- 2020Crossover from mean-field compression to collective phenomena in low-density foam-formed fiber materialcitations
- 2018Foam-formed fibre materials
- 2018Effect of cellulosic fibers on foam dynamics
- 2017Novel biobased micro- and nanomaterials in porous foam formed structures
- 2017Design-driven integrated development of technical and perceptual qualities in foam-formed cellulose fibre materialscitations
- 2017Design-driven integrated development of technical and perceptual qualities in foam-formed cellulose fibre materialscitations
- 2016Tailoring the microporous structure of fibre materials with foam carrier
- 2016Porous structure of fibre networks formed by a foaming process: a comparative study of different characterization techniquescitations
- 2015The effect of physical adhesion promotion treatments on interfacial adhesion in cellulose-epoxy
- 2014Wet fibre-laden foams in axial mixing with macro-instabilities
- 2013Bubble size and air content of wet fibre foams in axial mixing with macro-instabilitiescitations
- 2009Wet Web Rheology on a Paper Machine
- 2008Simulation of triaxial deformation of wet fiber networkscitations
Places of action
| Organizations | Location | People |
|---|
document
Lignin interdiffusion - a mechanism behind improved wet strength
Abstract
We have studied ways of improving strength properties of paper made from high yield pulps and lignin-rich chemical pulps by utilizing the thermoplastic properties of the lignin present in the fibre walls. Both dry and wet strength can be improved by hot pressing of sheets made from lignin-rich pulps. In this paper, we focus on aspects of the wet-strength development as a function of lignin content and temperature. Here we apply an activation energy evaluation approach to study lignin intermixing or interdiffusion. By means of hot pressing, it is possible to reach wet strength levels up to 50% of the dry strength level, provided that we use pulps with high enough lignin content. Our study included hot pressing of high yield pulps such as thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), high-temperature chemithermomechanicalpulps (HTCTMP), unbleached northern softwood kraft (NSK) and northern bleached softwood kraft (NBSK). The sheet pressing trials were performed for varied temperatures from room temperature up to 270°C. As the activation energy for the high yield pulps and the lignin-rich NSK were all in the range of 20-32 kJ/mol, we suggest that the wet strength development as function of temperature has a similar mechanism as long as the pulp fibres contain enough lignin. We also suggest that the phenomenon involves intermixing and/or interdiffusion of wood polymers between adjacent fibres when they are in a close contact. Most probably both the amorphous wood polymers, i.e. the linear hemicelluloses and the cross-linked lignin, mix with each other across the fibre-fibre or even more probable over the fibril-fibril contact surface. While the hemicellulose can intermix already at room temperature under moist conditions, the lignin intermixes more easily at the higher temperature we use. We do not know how far the hemicellulose or lignin could move within the fibre walls, but it seems that the amount of lignin present on the fibre surfaces plays an important role.