From eucalypt fiber distributions to technical properties of paper

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Aalto-yliopiston teknillinen korkeakoulu | Doctoral thesis (article-based)
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Degree programme
Verkkokirja (1843 KB, 74 s.)
Kemian laitetekniikan raporttisarja, 56
The objective of this thesis was to examine interfiber bonding and fiber segment activation as basic phenomena: how different raw material parameters and fiber property distributions affect bonding and activation, and in turn, how bonding and activation relate to end use properties of paper, especially to strength, structural and hygroexpansional properties. The raw materials for this study consisted of eucalypt fibers. The findings of this thesis work confirm what has already been established about bonding: raw material parameters, fiber treatments and process parameters all play a significant role in bonding and bonding development. A new observation was the interdependence of interfiber bonding and fiber network activation for structural and strength properties and the link observed between hygroexpansion and fiber network activation. Fiber size analyses were made with an optical analyzer that applies image analysis techniques on single fibers. The effects of fiber length, fiber width, fiber wall thickness, fines content and fiber curl distributions on the quality potential of eucalypt fibers were evaluated. The results of this work improved the understanding of the effects of fiber property distribution characteristics on paper technical properties. Fiber curl and fiber wall thickness were found to be the most promising fiber parameters in the evaluation of eucalypt fiber quality potential. In the development of parameters derived from fiber property distributions, the variations in paper technical properties were most often explained with fiber curl and fiber wall thickness. In addition to metafiber properties developed during this study (wet pressed density and activation parameter), more explicatory power was sought from the structure of fiber wall by means of simple water retention value and fiber saturation point measurements, differential scanning calorimetry, and by using solid-state cross-polarization/magic angle spinning (CP/MAS) 13C nuclear magnetic resonance measurements.
Supervising professor
Alopaeus, Ville, Prof.
Thesis advisor
Fiskari, Juha, Dr.
activation, fiber network
Other note
  • [Publication 1]: Iiro Pulkkinen, Kari Ala-Kaila, and Juhani Aittamaa. 2006. Characterization of wood fibers using fiber property distributions. Chemical Engineering and Processing, volume 45, number 7, pages 546-554.
  • [Publication 2]: Iiro Pulkkinen, Juha Fiskari, and Juhani Aittamaa. 2007. The effect of refining on fiber transverse dimension distributions of eucalyptus pulp species. O Papel, volume 68, number 5, pages 58-66.
  • [Publication 3]: Iiro Pulkkinen, Ville Alopaeus, Juha Fiskari, and Olli Joutsimo. 2008. The use of fibre wall thickness data to predict handsheet properties of eucalypt pulp fibres. O Papel, volume 69, number 10, pages 71-85.
  • [Publication 4]: Iiro Pulkkinen, Juha Fiskari, and Ville Alopaeus. 2009. The effect of hardwood fiber morphology on the hygroexpansivity of paper. BioResources, volume 4, number 1, pages 126-141.
  • [Publication 5]: Iiro Pulkkinen, Juha Fiskari, and Ville Alopaeus. 2009. The effect of sample size and shape on the hygroexpansion coefficient - A study made with advanced methods for hygroexpansion measurement. TAPPSA Journal, March 2009, pages 26-33.
  • [Publication 6]: Iiro Pulkkinen, Juha Fiskari, and Ville Alopaeus. 2010. New model for predicting tensile strength and density of eucalyptus handsheets based on an activation parameter calculated from fiber distribution characteristics. Holzforschung, volume 64, number 2, pages 201-209.
  • [Publication 7]: Iiro Pulkkinen, Juha Fiskari, and Ville Alopaeus. 2009. CPMAS 13C NMR analysis of fully bleached eucalypt pulp samples: Links to handsheet hygroexpansivity and strength properties. Journal of Applied Sciences, volume 9, number 22, pages 3991-3998.
  • [Publication 8]: Stefan Antonsson, Iiro Pulkkinen, Juha Fiskari, Katarina Karlström, and Mikael E. Lindström. 2010. The relationship between hygroexpansion, tensile stiffness, and mechano-sorptive creep in bleached hardwood kraft pulps. Appita Journal, volume 63, number 3, pages 225, 231-234.