Abstract
The modification of bleached never-dried cellulose fibers was studied under controlled compression and shearing conditions. Fibers were further treated in a high-intensity mixing device in low-consistency to determine if the fiber structure was weakened in the in-pad attrition. The difference between the development of the softwood and hardwood fibers was examined. The fiber properties were analyzed using a fiber morphology analyzer, fractional fiber analysis and an electron microscope. The results indicate that the shearing under the controlled compression at high consistency modified the softwood and hardwood fibers already at low-energy consumptions. The fiber length and width decreased, and the formation of curls and kinks was pronounced. However, the intensive mixing after in-pad attrition revealed that the fiber structure was not weakened under compression and shear forces; conversely, the fiber cell wall was more resistant for the intensive mixing. When comparing the results for hardwood and softwood fibers, the softwood fibers were more modified during in-pad attrition, whereas the fiber wall strengthening was more significant in the hardwood fibers.
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References
Alén R (2000) Structure and chemical composition of wood. In: Stenius P (ed) Papermaking science and technology book 3: papermaking part 1, forest products chemistry, 1st edn. Fapet Oy, Helsinki, Finland, pp 11–57
Bäckström M, Kolar MC, Htun M (2008) Characterisation of fines from unbleached kraft pulps and their impact on sheet properties. Holzforschung 62:546–552
Bergander A, Salmén L (2002) Cell wall properties and their effects on the mechanical properties of fibers. J Mater Sci 37:151–156
Chakraborty A, Sain M, Kortschot M (2005) Cellulose microfibrils: a novel method of preparation using high shear refining and cryocryshing. Holzforschung 59:102–107
Donaldson L (2008) Microfibril angle: measurement, variation and relationships—a review. IAWA J 29(4):345–386
Fardim P, Durán N (2003) Modification of fibre surfaces during pulping and refining as analysed by SEM, XPS and ToF-SIMS. Colloids Surf A Physicochem Eng Aspects 223:263–2276
Fernando D, Daniel G (2004) Micro-morphological observations on spruce TMP fibre fractions with emphasis on fibre cell wall fibrillation and splitting. Nordic Pulp Paper Res J 19(3):278–285
Hamad WY (1998) On the mechanism of cumulative damage and fracture in native cellulose fibres. J Mater Sci 17:433–436
Hamad WY, Provan JW (1995) Microstructural cumulative material degradation and fatigue-failure micromechanisms in wood-pulp fibres. Cellulose 2:159–177
Hartler N (1995) Aspects on curled and microcompressed fibers. Nordic Pulp Paper Res J 1:4–7
Hartman RR (1984) Mechanical treatment of pulp fibers for property development, dissertation. The institute of Paper Science and Technology, Atlanta, Georgia
Illikainen M, Niinimäki J (2007) Energy dissipation in a TMP refiner disc gap. In: Proceedings of the 6th Biennal Johan Gullichsen Colloquium, Espoo, Finland, pp 49–57
Illikainen M, Härkönen E, Ullmar M, Niinimäki J (2008) Disruptive shear stress in spruce and pine TMP pulps. Paperi Ja Puu Paper Timber 90(1):47–52
Karnis A (1989) High-consistency refining of bleached sulfate pulps. Tappi J 72(6):96–102
Karnis A (1994) The mechanism of fibre development in mechanical pulping. J Pulp Paper Sci 20(10):J280–J288
Koskenhely K (2008) Refining of chemical pulp fibres. In: Paulapuro H (ed) Papermaking science and technology book 8: papermaking part 1, stock preparation and wet end, 2nd edn. Finnish Paper Engineers’ Association/Paperi ja Puu Oy, Helsinki, Finland, pp 94–139
Laine C, Wang X, Tenkanen M, Varhimo A (2004) Changes in the fiber wall during refining of bleached pine kraft pulp. Holzforschung 58:233–240
Laitinen O (2011) Utilisation of tube flow fractionation in fibre and particle analysis, dissertation. Department of process and environmental engineering, University of Oulu, Finland
Lowe RM, Page DH, Waterhouse JF, Hsieh J, Cheluka N, Ragauskas AJ (2007) Deformation behavior of wet lignocellulosic fibers. Holzforschung 61:261–266
Lumiainen J (2000) Refining of chemical pulp. In: Paulapuro H (ed) Papermaking science and technology book 8: papermaking part 1, stock preparation and wet end, 1st edn. Fapet Oy, Helsinki, Finland, pp 87–122
Lundin T, Batchelor W, Fardim P (2008) Fiber trapping in low-consistency refining: new parameter to describe the refining process. Tappi J 7(7):15–21
Luo XL, Zhu JY, Gleisner R, Zhan HY (2011) Effects of wet-pressing-induced fiber hornification on enzymatic saccharification of lignocelluloses. Cellulose 18:1055–1062
Mahoney TC, Paulapuro H (1999) The formation of pores in the cell wall. J Pulp Paper Sci 25(12):430–436
Marton R, Agarwal AK (1965) Papermaking properties of hardwood vessel elements. Tappi J 48(5):264–269
Miles KB, Karnis A (1991) The response of mechanical and chemical pulps to refining. Tappi J 74(1):157–164
Page DH (1989) The beating of chemical pulps—the action and effect. 9th Fundamental Research Symposium Notes, UK, Cambridge, p 1
Salmén L, Burgert I (2009) Cell wall features with regard to mechanical performance. A review. Holzforschung 63(2):121–129
Sjöberg JC, Höglund H (2007) High consistency refining of kraft pulp for reinforcing paper based on TMP furnishes. International Mechanical Pulping Conference, Minneapolis, Minnesota, USA
Stone JE, Scallan AM, Abrahamson B (1968) Influence of beating on cell wall swelling and internal fibrillation. Svensk Papperstidning 19:687–694
Wang X, Maloney TC, Paulapuro H (2007) Fibre fibrillation and its impact on sheet properties. Paperi Ja Puu Paper Timber 89(3):148–151
Xu EC, Koefler H, Antensteiner P (2003) Some latest developments in alkali peroxide mechanical pulping, part 2: low consistency secondary refining. Pulp Paper Canada 104(10):T256–T260
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The authors thank Mr. Jani Österlund for his help during the practical work and the Graduate School in Chemical Engineering (GSCE) for the financial support.
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Kekäläinen, K., Illikainen, M. & Niinimäki, J. Morphological changes in never-dried kraft fibers under mechanical shearing. Cellulose 19, 879–889 (2012). https://doi.org/10.1007/s10570-012-9670-z
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DOI: https://doi.org/10.1007/s10570-012-9670-z