Elucidating the nature of bonding in mechanical pulps

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Please use this identifier to cite or link to this item: http://hdl.handle.net/1853/7096

Title: Elucidating the nature of bonding in mechanical pulps
Author: Lehtonen, Lauri Kalevi
Abstract: Bond strength is classically characterized into two separate factors; area of the bond and specific bond strength. This separation is especially important in pulps that lack strength properties, and are specifically used for their optical properties, such as mechanical pulps. In this research the applicability of the Ingmansson and Thode method for distinguishing between specific bonded area and specific bond strength in mechanical pulps is studied. It is shown that the rigid, non-collapsable, nature of the mechanical pulp can be overcome by press drying the sheets until they approach their 50% relative humidity moisture content. Mechanical pulps have been assumed to operate in a domain where fiber failure can be considered insignificant, and the bonded area to tensile strength relationship is linear. In this study it was shown that most commercial pulps operate in a significant fiber failure domain. However, it is shown that pure fines and fines rich mechanical pulp better follow a linear bonded area to tensile strength relationship rather than a non-linear (significant fiber failure) model, suggesting that only the fiber fraction undergoes fiber failure and the finer fractions predominantly bond failure. The Ingmansson and Thode method relies on the use of scattering coefficient as a measure of specific surface area. It is shown that scattering coefficient is an accurate estimate of mechanical pulp specific surface area at a constant wavelength of light, provided that the wavelength used to measure scattering coefficient is above the significant absorption limit.
Type: Dissertation
URI: http://hdl.handle.net/1853/7096
Date: 2004-11
Publisher: Georgia Institute of Technology
Subject: Pulp mixtures
Scattering coefficient
Fiber properties
Paper properties
Fines
Paper physics
Heterogeneous
Mechanical pulps
Department: Institute of Paper Science and Technology
Advisor: Committee members: Alan Rudie, Derek Page, Douglas Coffin, and Timothy Patterson
Degree: Ph.D.

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