Wet fibre surface - does it behave like a gel?

Annika Ketola, Miika Leppänen, Tuomas Turpeinen, Petri Papponen, Anna Sundberg, Kai Arstila, Elias Retulainen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


The physico-chemical characteristics of wet fibre surfaces and their role in fibre bonding and paper properties have been under debate and research for decades. The gel-likeness of the fibre surfaces has been addressed in many studies but has not been explicitly demonstrated. In this study, the structure of wet beaten kraft pulp fibre surface and its similarity with microfibrillated cellulose (CMF) was shown using helium ion microscopy (HIM) imaging. Beaten kraft fibres and CMF were dried using two mild drying methods to preserve the delicate fibrillated structures. The fibre surface had a strong resemblance with gel-like CMF material. The amount of external fibrillation varied along the fibre length and was often shown to extend tens of micrometers from the fibre surface. The gel-like behaviour of wet fibrillated material was demonstrated using rheological tests. The examined CMF and CNF samples with solids contents of 1.97% and 1.06%, respectively, showed gel-like behaviour. A low gelling point suggests that fibrillated fibre surfaces have the ability to transfer forces at very low consistencies, and that the ability increases as a power function of the solids content. This is assumed to play a remarkable role in increasing inter-fibre adhesion and in transmitting inter-fibre forces within consolidating webs, whether arising from external tensions or internal drying stresses.
Original languageEnglish
Title of host publicationAdvances in Pulp and Paper Research, Cambridge 2022
Subtitle of host publicationTransactions of the 17th Fundamental Research Symposium
EditorsDouglas W. Coffin, Warren J. Batchelor
PublisherPulp & Paper Fundamental Research Society
ISBN (Print)978-0-9926163-6-6
Publication statusPublished - 29 Aug 2022
MoE publication typeA4 Article in a conference publication
Event17th Fundamental Research Symposium - Cambridge, United Kingdom
Duration: 29 Aug 20221 Sept 2022


Conference17th Fundamental Research Symposium
Country/TerritoryUnited Kingdom


Dive into the research topics of 'Wet fibre surface - does it behave like a gel?'. Together they form a unique fingerprint.

Cite this