Abstract
De-esterification and sulfonation reactions, which create new anionic groups in the middle lamella and primary wall layers, are the key chemical reactions in chemithermomechanical pulping. The effects of these reactions on the resulting fibre dimensions, refining energy demand, hand-sheet bulk and strength properties were assessed by laboratory-scale chemical pre-treatments and refining of Norway spruce chips. After pre-treatments with alkaline, sulfite, alkaline sulfite and alkaline peroxide liquors, a Wing defibrator-type batch refiner was used. The refining energy was measured. The degree of alkaline hydrolysis of acetyl and methyl ester groups in galactoglucomannans (GGMs) and pectins, and the degree of lignin sulfonation were determined. Hand-sheets were prepared and their physical properties were tested. The data were subjected to multivariate analysis and the order of significance of the chemical reactions towards pulp and paper properties was estimated. Chemical pre-treatments were found to increase the fibre length and the energy demand considerably. The fibre length and width after refining were strongly influenced by lignin sulfonation and pectin demethylation. GGM deacetylation had little influence on preserving the fibre dimensions in CTMP refining. The bulk, on the other hand, was highly influenced by GGM deacetylation. Peroxide reactions in alkaline peroxide treatments had no effect on the pulp and paper properties.
References
Atack, D., Heitner, C., Stationwala, M.I. (1978) Ultra high yield pulping of eastern black spruce. Svensk Papperstidn.81:164–176.Search in Google Scholar
Atack, D., Heitner, C., Stationwala, M.I. (1980) Ultra high yield pulping of eastern black spruce Part 2. Svensk Papperstidn.83:133–141.Search in Google Scholar
Beatson, R.P., Heitner, C., Atack, D. (1984) Factors affecting the sulphonation of spruce. J. Pulp Pap. Sci.10:12–17.Search in Google Scholar
Hafrén, J., Daniel, G. (2003) Distribution of methyl-esterified galacturonan in chemical and mechanical pulp fibres. J. Wood Sci.49:361–365.10.1007/s10086-002-0488-4Search in Google Scholar
Hatton, J.V., Johal, S.S. (1996) Mechanical pulping of commercial thinnings of six softwoods from New Brunswick. Pulp Pap. Can.97:93–97.Search in Google Scholar
Holmbom, B., Pranovich, A. (1998) Fibre chemistry of alkaline treatment and peroxide bleaching of mechanical pulp. In: Proceedings of the 5th European Workshop on Lignocellulosics and Pulp, Aveiro. pp. 559–562.Search in Google Scholar
ISO standard (1998) ISO 5263:1995, Pulps – Laboratory wet disintegration.Search in Google Scholar
ISO standard (1998) ISO 5269-1:1979, Pulps – Preparation of laboratory sheets for physical testing Part 1: Conventional sheet formed method.Search in Google Scholar
ISO standard (1998) ISO 5267-2:1980, Pulps – Determination of drainability Part 2: “ Canadian Standard ” freeness method.Search in Google Scholar
ISO standard (1998) ISO 5270:1979, Pulps – Laboratory sheets – Determinations of physical properties.Search in Google Scholar
Iwamida, T., Sumi, Y., Nakano, J. (1980) Mechanisms of softening and refining in high yield sulfite pulping processes. Cell. Chem. Technol.14:253–268.Search in Google Scholar
Katz, S., Liebergott, N., Scallan A.M. (1981) A mechanism for the alkali strengthening of mechanical pulps. Tappi64:97–100.Search in Google Scholar
Konn, J., Holmbom, B., Nickull O. (2002) Chemical reactions in chemimechanical pulping: Material balances of wood components in a CTMP process. J. Pulp Pap. Sci.28:395–399.Search in Google Scholar
Konn, J., Pranovich, A., Holmbom B. (2006) Dissolution of fibre material in alkaline pre-treatment and refining of spruce CTMP. Holzforschung60:32–39.10.1515/HF.2006.007Search in Google Scholar
Lai, Y.-Z., Iwamida, T. (1992) Effects of chemical treatment on ultra-high-yield pulping. II. Fibre properties of Norway spruce chemimechanical pulps. Cell. Chem. Technol.26:333–344.Search in Google Scholar
Miles, K.B., Karnis, A. (1993) The refining characteristics of chemimechanical pulps. Tappi J.76:181–188.Search in Google Scholar
Öhlander, K., Salmén, L., Htun, M. (1989) Relation between mechanical properties of pulp fibres and the activation energy of softening as affected by sulfonation. Nord. Pulp Pap. Res. J.5:60–64.Search in Google Scholar
Page, D.H. (1994) A note on the mechanism of tearing strength. Tappi J.77:201–203.Search in Google Scholar
Pan, G.X. (2004) Relationship between dissolution of fibre materials and development of pulp strength in alkaline peroxide bleaching of mechanical pulp. Holzforschung58:369–374.10.1515/HF.2004.056Search in Google Scholar
Peng, F., Johansson, L. (1996) Characterisation of mechanical pulp fibres. J. Pulp Pap. Sci.22:252–257.Search in Google Scholar
Pranovich, A.V., Eckerman, C., Holmbom, B. (2002) Determination of methanol released from wood and mechanical pulp by headspace solid-phase microextraction. J. Pulp Pap. Sci.28:199–203.Search in Google Scholar
Pranovich, A.V., Sundberg, K., Holmbom, B. (2003) Chemical changes in thermomechanical pulp at alkaline conditions. J. Wood Chem. Technol.23:89–112.Search in Google Scholar
Salmén, L., Petterson, B. (1995) The primary wall; important for the fibre separation in mechanical pulping. Cell. Chem. Technol.29:331–337.Search in Google Scholar
Scallan, A.M. (1983) The effect of acidic groups on the swelling of pulps: A review. Tappi J.66:73–75.Search in Google Scholar
Sundberg, A., Sundberg, K., Lillandt, C., Holmbom, B. (1996) Determination of hemicelluloses and pectin in wood and pulp fibres by acid methanolysis and gas chromatography. Nord. Pulp Pap. Res. J.11:216–219, 226.Search in Google Scholar
Sundström, L., Brolin, A., Hartler, N. (1993) Fibrillation and its importance for the properties of mechanical pulp fibre sheets. Nord. Pulp Pap. Res. J.8:379–383.10.3183/npprj-1993-08-04-p379-383Search in Google Scholar
Westermark, U., Samuelsson, B. (1993) A spectrophotometric method for the determination of sulfonic acids in wood material. Nord. Pulp Pap. Res. J.8:358–359, 398.10.3183/npprj-1993-08-04-p358-359Search in Google Scholar
Westermark, U., Vennigerholz, F. (1995) Morphological distribution of acidic and methylesterified pectin in the wood cell wall. In: Proceedings of the 8th International Symposium on Wood Pulping Chemistry, Helsinki, Vol. 1. pp. 101–106.Search in Google Scholar
Westermark, U., Hardell, H.-L., Iversen, T. (1986) The content of protein and pectin in the middle lamella/primary wall from spruce wood. Holzforschung40:65–68.10.1515/hfsg.1986.40.2.65Search in Google Scholar
Westermark, U., Samuelsson, U., Simonson, R., Pihl, R. (1987) Investigation of a selective sulfonation of wood chips. Part 5. Thermomechanical pulping with low addition of sulfite. Nord. Pulp Pap. Res. J.2:146–151.10.3183/npprj-1987-02-04-p146-151Search in Google Scholar
Zhang, Y., Sjögren, B., Engstrand, P., Htun, M. (1994) Determination of charged groups in mechanical pulp fibres and their influence on pulp properties. J. Wood Chem. Technol.14:83–102.10.1080/02773819408003087Search in Google Scholar
©2006 by Walter de Gruyter Berlin New York