Date of Award
Bachelor of Science
Paper Science and Engineering
A batch of chips was subjected to an oxygen pulping and a kraft pulping system. The resulting pulp was tested in its unbleached condition. It was then bleached, tested again. Handsheets were tested using the Pulmac zero span tensile tester and other standard physical tests. The pulps were tested using the Pulmac permeability tester. This procedure gave the opportunity to look at how the differences between the individual fibers and their components affect the differences in the strength between oxygen and kraft pulp handsheets.
The oxygen pulp was severely degraded than was the kraft pulp. This led to shorter, weaker individual fibers, but fibers with better bondability. The increased bondability gave oxygen pulp handsheets with superior strength in every test except tear. The increased bondability was caused by the higher hemicellulose content in the oxygen pulp. Bleaching increased the strength of both pulps, but oxygen pulp strength was increased to a higher degree. The oxygen pulp also had a larger specific surface area than did the kraft pulp. This increased the number of sites available for bonding which helped to increase the sheet strength. For these handsheets, the bondability played a more important role in the final strength than did the strength of the individual fibers.
Pobanz, Jeff C., "How Lignin, Hemicellulose, and Cellulose Affect the Properties of Oxygen Versus Kraft Pulps" (1977). Paper Engineering Senior Theses. 399.