A1 Journal article (refereed)
Lignin Inter-Diffusion Underlying Improved Mechanical Performance of Hot-Pressed Paper Webs (2021)

Mattsson, A., Joelsson, T., Miettinen, A., Ketoja, J. A., Pettersson, G., & Engstrand, P. (2021). Lignin Inter-Diffusion Underlying Improved Mechanical Performance of Hot-Pressed Paper Webs. Polymers, 13(15), Article 2485. https://doi.org/10.3390/polym13152485

JYU authors or editors

Publication details

All authors or editors: Mattsson, Amanda; Joelsson, Tove; Miettinen, Arttu; Ketoja, Jukka A.; Pettersson, Gunilla; Engstrand, Per

Journal or series: Polymers

eISSN: 2073-4360

Publication year: 2021

Publication date: 28/07/2021

Volume: 13

Issue number: 15

Article number: 2485

Publisher: MDPI AG

Publication country: Switzerland

Publication language: English

DOI: https://doi.org/10.3390/polym13152485

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/77608

Abstract

Broader use of bio-based fibres in packaging becomes possible when the mechanical properties of fibre materials exceed those of conventional paperboard. Hot-pressing provides an efficient method to improve both the wet and dry strength of lignin-containing paper webs. Here we study varied pressing conditions for webs formed with thermomechanical pulp (TMP). The results are compared against similar data for a wide range of other fibre types. In addition to standard strength and structural measurements, we characterise the induced structural changes with X-ray microtomography and scanning electron microscopy. The wet strength generally increases monotonously up to a very high pressing temperature of 270 °C. The stronger bonding of wet fibres can be explained by the inter-diffusion of lignin macromolecules with an activation energy around 26 kJ mol−1 after lignin softening. The associated exponential acceleration of diffusion with temperature dominates over other factors such as process dynamics or final material density in setting wet strength. The optimum pressing temperature for dry strength is generally lower, around 200 °C, beyond which hemicellulose degradation begins. By varying the solids content prior to hot-pressing for the TMP sheets, the highest wet strength is achieved for the completely dry web, while no strong correlation was observed for the dry strength.

Keywords: pulp and paper industry; paper; packaging material; manufacturing; ecological character; fibres; lignin; diffusion (physical phenomena); temperature; tensile strength; biotechnology; biophysics

Free keywords: hot-pressing; paper web; fibre; lignin; diffusion; activation energy

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2021

JUFO rating: 1