Effect of mechanically induced micro deformations on extensibility and strength of individual softwood pulp fibers and sheets

Jarmo Kouko (Corresponding Author), Marina Jajcinovic, Wolfgang Fischer, Annika Ketola, Ulrich Hirn, Elias Retulainen

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)

Abstract

Abstract: Tensile tests of individual bleached kraft pulp fibers and paper sheets of industrial origin were conducted in order to investigate the effect of refining and small-scale fiber deformations on the extensibility of fibers and paper. The shape of the tensile curves of most of the fibers was concave upward (i.e., increasing slope) and consisted of two or three phases suggesting that the fibrillar structure and disordered regions in the fiber wall were straightened out during straining. Only a few of the individual BSKP fiber tensile curves were apparently linear. Elongation of the individual kraft fibers varied from 8 to 32% and the average elongation was not increased by high consistency refining. Tensile test results of laboratory sheets made of the same BSKP pulp suggested that the fiber bonding not only governs paper strength, but also is highly relevant for the elongation of fiber networks. The key conclusion related to this investigation and freely dried sheets was that the increased network elongation and strength after refining is mainly due to increased inter-fiber bonding and a higher shrinkage tendency of the fiber network and not due to the increased elongation or strength of individual fibers. Graphical abstract: [Figure not available: see fulltext.].

Original languageEnglish
Pages (from-to)1995-2012
Number of pages18
JournalCellulose
Volume26
Issue number3
DOIs
Publication statusPublished - 15 Feb 2019
MoE publication typeNot Eligible

Fingerprint

Softwoods
Pulp
Fibers
Elongation
Fiber bonding
Refining
Bleached pulp
Kraft pulp

Keywords

  • Individual softwood pulp fiber
  • Single fiber elongation
  • Stress–strain curve
  • Tensile testing
  • Viscose fiber

Cite this

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title = "Effect of mechanically induced micro deformations on extensibility and strength of individual softwood pulp fibers and sheets",
abstract = "Abstract: Tensile tests of individual bleached kraft pulp fibers and paper sheets of industrial origin were conducted in order to investigate the effect of refining and small-scale fiber deformations on the extensibility of fibers and paper. The shape of the tensile curves of most of the fibers was concave upward (i.e., increasing slope) and consisted of two or three phases suggesting that the fibrillar structure and disordered regions in the fiber wall were straightened out during straining. Only a few of the individual BSKP fiber tensile curves were apparently linear. Elongation of the individual kraft fibers varied from 8 to 32{\%} and the average elongation was not increased by high consistency refining. Tensile test results of laboratory sheets made of the same BSKP pulp suggested that the fiber bonding not only governs paper strength, but also is highly relevant for the elongation of fiber networks. The key conclusion related to this investigation and freely dried sheets was that the increased network elongation and strength after refining is mainly due to increased inter-fiber bonding and a higher shrinkage tendency of the fiber network and not due to the increased elongation or strength of individual fibers. Graphical abstract: [Figure not available: see fulltext.].",
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Effect of mechanically induced micro deformations on extensibility and strength of individual softwood pulp fibers and sheets. / Kouko, Jarmo (Corresponding Author); Jajcinovic, Marina; Fischer, Wolfgang; Ketola, Annika; Hirn, Ulrich; Retulainen, Elias.

In: Cellulose, Vol. 26, No. 3, 15.02.2019, p. 1995-2012.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Effect of mechanically induced micro deformations on extensibility and strength of individual softwood pulp fibers and sheets

AU - Kouko, Jarmo

AU - Jajcinovic, Marina

AU - Fischer, Wolfgang

AU - Ketola, Annika

AU - Hirn, Ulrich

AU - Retulainen, Elias

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N2 - Abstract: Tensile tests of individual bleached kraft pulp fibers and paper sheets of industrial origin were conducted in order to investigate the effect of refining and small-scale fiber deformations on the extensibility of fibers and paper. The shape of the tensile curves of most of the fibers was concave upward (i.e., increasing slope) and consisted of two or three phases suggesting that the fibrillar structure and disordered regions in the fiber wall were straightened out during straining. Only a few of the individual BSKP fiber tensile curves were apparently linear. Elongation of the individual kraft fibers varied from 8 to 32% and the average elongation was not increased by high consistency refining. Tensile test results of laboratory sheets made of the same BSKP pulp suggested that the fiber bonding not only governs paper strength, but also is highly relevant for the elongation of fiber networks. The key conclusion related to this investigation and freely dried sheets was that the increased network elongation and strength after refining is mainly due to increased inter-fiber bonding and a higher shrinkage tendency of the fiber network and not due to the increased elongation or strength of individual fibers. Graphical abstract: [Figure not available: see fulltext.].

AB - Abstract: Tensile tests of individual bleached kraft pulp fibers and paper sheets of industrial origin were conducted in order to investigate the effect of refining and small-scale fiber deformations on the extensibility of fibers and paper. The shape of the tensile curves of most of the fibers was concave upward (i.e., increasing slope) and consisted of two or three phases suggesting that the fibrillar structure and disordered regions in the fiber wall were straightened out during straining. Only a few of the individual BSKP fiber tensile curves were apparently linear. Elongation of the individual kraft fibers varied from 8 to 32% and the average elongation was not increased by high consistency refining. Tensile test results of laboratory sheets made of the same BSKP pulp suggested that the fiber bonding not only governs paper strength, but also is highly relevant for the elongation of fiber networks. The key conclusion related to this investigation and freely dried sheets was that the increased network elongation and strength after refining is mainly due to increased inter-fiber bonding and a higher shrinkage tendency of the fiber network and not due to the increased elongation or strength of individual fibers. Graphical abstract: [Figure not available: see fulltext.].

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