Solid state NMR studies on inhomogeneous structure of fibre wall in kraft pulp

Tiina Liitiä, Sirkka-Liisa Maunu, Bo Hortling

Research output: Contribution to journalArticleScientificpeer-review

25 Citations (Scopus)

Abstract

Solid state NMR spectroscopy was used to analyse the inhomogeneous structure of kraft fibre. Primary fines, isolated from the original kraft pulp, and secondary fines, isolated after refining, were compared with the corresponding long fibres. To fractionate fibre wall surface material, the kraft pulp was refined in stages. After each stage, the secondary fines and long fibres were separated and the long fibres refined again to peel off the surface material. It was found that the crystallinity of cellulose is lower in fines compared with the corresponding long fibres. When the fines fractions were compared with each other, the cellulose crystallinity was observed to increase towards the inner parts of the fibre surface. A very clear gradient was also seen in the amount of extractives, which was highest in the primary fines rich in ray cells. The contents of lignin and some hemicelluloses, mainly xylan and glucomannan, were also higher in fines. Residual lignin isolated from the fines was found to be slightly more condensed than residual lignin from long fibres.
Original languageEnglish
Pages (from-to)503-510
JournalHolzforschung
Volume55
Issue number5
DOIs
Publication statusPublished - 2001
MoE publication typeNot Eligible

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Kraft pulp
Nuclear magnetic resonance
Fibers
Lignin
Cellulose
Xylans
Nuclear magnetic resonance spectroscopy
Refining

Cite this

Liitiä, Tiina ; Maunu, Sirkka-Liisa ; Hortling, Bo. / Solid state NMR studies on inhomogeneous structure of fibre wall in kraft pulp. In: Holzforschung. 2001 ; Vol. 55, No. 5. pp. 503-510.
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Solid state NMR studies on inhomogeneous structure of fibre wall in kraft pulp. / Liitiä, Tiina; Maunu, Sirkka-Liisa; Hortling, Bo.

In: Holzforschung, Vol. 55, No. 5, 2001, p. 503-510.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Liitiä, Tiina

AU - Maunu, Sirkka-Liisa

AU - Hortling, Bo

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AB - Solid state NMR spectroscopy was used to analyse the inhomogeneous structure of kraft fibre. Primary fines, isolated from the original kraft pulp, and secondary fines, isolated after refining, were compared with the corresponding long fibres. To fractionate fibre wall surface material, the kraft pulp was refined in stages. After each stage, the secondary fines and long fibres were separated and the long fibres refined again to peel off the surface material. It was found that the crystallinity of cellulose is lower in fines compared with the corresponding long fibres. When the fines fractions were compared with each other, the cellulose crystallinity was observed to increase towards the inner parts of the fibre surface. A very clear gradient was also seen in the amount of extractives, which was highest in the primary fines rich in ray cells. The contents of lignin and some hemicelluloses, mainly xylan and glucomannan, were also higher in fines. Residual lignin isolated from the fines was found to be slightly more condensed than residual lignin from long fibres.

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