Enhancing strength properties of kraft and CTMP fibre networks

E Retulainen, Kaarina Nieminen, Ilkka Nurminen

Research output: Contribution to journalArticleScientificpeer-review


In this study possibilities to increase the strength of paper without causing deterioration on the optical properties were examined. Starches of different cationicity were applied to the long fibre fractions of a CTMP and a bleached kraft pulp and the effect of fines and dry strength additives was studied. The starch adsorption depended both on the anionicity of the pulp and the cationicity of the starch. The amount adsorbed was clearly greater with CTMP fibres despite of their lower surface area. The same starch, one of low cationicity, proved to be the most efficient strength aid with both types of fibres. The tensile strength of CTMP sheets could not, however, be increased much by addition of starch due to the low conformability of the fibres. The tensile strength of the kraft fibre network was increased appreciably by a kraft fines addition and the light scattering was increased by a TMP fines addition. In both cases, if the starch was added to the long fibres before fines addition, the tensile strength improved significantly. The results demonstrate the great potential of using fines properties as active control variables.
Original languageEnglish
Pages (from-to)33-38
JournalAppita Journal
Issue number1
Publication statusPublished - 1993
MoE publication typeA1 Journal article-refereed


  • fines
  • strength properties
  • optical properties
  • bonding
  • cationic starch


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