Determination of Strength Properties of Pine and Its Comparison with Birch and Eucalyptus

Abstract

The purpose of this bachelor’s thesis was to analyze the strength properties of pine (Pinus Sylvestris) Kraft pulp required for paper making process. This thesis also compares the result with the earlier study done on birch (Betula pendula) and eucalyptus (Eucalyptus Grandis) which were part of an ongoing research on different wood species and their properties by Saimaa University of Applied Sciences, Imatra.

In the experimental part, two different types of Kraft pulp were studied; one with low lignin content and the other with high lignin content. These pulps were ob-tained after pulping fresh pine chips in liquid circulated batch digester by Kraft pulping process. Screened pulps were beaten in PFI mill to different degrees. Handsheets were made with Rapid Köthen equipment. Different strength and optical properties were measured from the prepared sheets. This study on pine is compared with the earlier studies done on birch and eucalyptus. The result reflects basic comparison of pine with birch and eucalyptus but does not deal with details.

Although these species could not be compared directly due to various pros and cons of individual species, general conclusions were derived. Long and strong fibres of pine pulped by Kraft process provides possibility to manufacture strong and durable end product, whereas birch and eucalyptus are well known for good formation, superior opacity and in addition to that, they could be bleached to higher brightness level compared to pine. If these species are combined, the end product will be much better compared to one particular species.