The Area of Molecular Contact in Fiber-Fiber Bonds
2013 (English)In: Advances in Pulp and Paper Reserach, Cambridge 2013: Transactions of the 15th Fundamental Research Symposium / [ed] S.J. I'Anson, 2013, 201-223 p.Conference paper (Refereed)
We are presenting a coherent theoretical concept as well as empirical evidence suggesting that there is a high degree of molecular contact in fiberfiber bonds, the surfaces might even be in full contact.
Fundamental theoretical relations from contact mechanics governing the area in molecular contact between surfaces are reviewed and proposed for the quantitative analysis of the area in molecular contact in fiber-fiber bonds.
The key parameters determining the degree of molecular contact according to the theory are indentation hardness and elastic modulus of the wet pulp fibers, surface roughness of the wet fibers and the pressure applied to the fiber bonds during bond formation.
We provide results for fiber indentation hardness and effective elastic modulus from nanoindentation measurements of fiber surfaces at varying relative humidity and in water. The fiber surface properties have been determined with an atomic force microscopy technique specifically designed to measure soft, viscoelastic materials. Also, surface roughness has been measured in the wet and dry state.
Experiments with individual fiber-fiber joints show that the breaking strength of these joints is independent from the pressure during bond formation indicating that the surfaces in fiber-fiber bonds are in a high degree of molecular contact, maybe even full contact. This is the case even if they are formed without external pressure. Computer simulations of the degree of mechanical contact of fiber surfaces during drying were performed indicating that capillary adhesion is pulling the fiber surfaces into a high degree of molecular contact. These findings are discussed with respect to the literature considering FRET microscopy and Transmission Electron Microscopy of fiber-fiber bonds.
Place, publisher, year, edition, pages
2013. 201-223 p.
Paper, Pulp and Fiber Technology Applied Mechanics
IdentifiersURN: urn:nbn:se:kth:diva-136449ISBN: 978-0-9926163-0-4OAI: oai:DiVA.org:kth-136449DiVA: diva2:676214
15th Fundamental Research Symposium Held in Cambridge: September 8-13, 2013
QC 201401312013-12-052013-12-052014-01-31Bibliographically approved