PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL FROM THE PUBLISHERS OF PAPER TE Volume 7, Number 2, 2021
On the strength improvement of lightweight fibre networks by polymers, fibrils and fines Tiina Pöhler, Jukka A. Ketoja, Timo Lappalainen, Veli-Matti Luukkainen, Ilkka Nurminen, Panu Lahtinen & Katariina Torvinen Novel lightweight cellulose fibre materials containing various strength enhancing polymeric and fibrillar components were formed with the help of foam technology. Increasing inter-fibre bond strength and local material density was attempted with unique lignin-containing wood fines (V-fines), cellulose microfibrils (CMF), TEMPO-oxidized cellulose nanofibrils (TCNF), and macromolecules such as cationic starch, polyvinyl alcohol (PVA), and locust bean gum (LBG). The investigated fibres included both long hemp bast fibres and northern bleached softwood Kraft pulp. In the low-density range of 38 – 52 kg/m3, the compression stress and modulus were highly sensitive to inter-fibre bond properties, the multi-scale features of the fibre network, and the foaming agent employed. Still, the compression-stress behaviour in most cases approached the same theoretical curve, derived earlier by using a mean-field theory to describe the deformation behaviour. At 10% addition level of fine components, the specific compression stress and compression modulus increased in the order of V-fines\CMF\TCNF. A tremendous increase in the compression modulus was obtained with LBG, leading to a material surface that was very hard. In general, the foams made with PVA, which acts both as foaming agent and reinforcing macromolecule, led to better strength than what was obtained with a typical anionic sodium dodecyl sulphate surfactant. Strength could be also improved by refining the softwood pulp. Contact information: Solutions for Natural Resources and Environment, VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044 Espoo, Finland
Cellulose (2020) 27:6961 – 6976 https://doi.org/10.1007/s10570-020-03263-x Creative Commons Attribution 4.0 International License
The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology International and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .
Article 1 – Foam Forming & Strength Improvement
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