Date of Award
Bachelor of Science
Paper Science and Engineering
Recycled paper is a viable and economical source of useful wood fiber for paper manufacture. Two of the largest contributors to today's paper waste stream are Mixed-Office Waste (Softwood Kraft Pulp) and Newsprint (Stone Groundwood Pulp). When paper is recycled the fibers are unavoidably, and irreversibly damaged. This damage is caused by Hornification (irreversible effect of re-drying fibers) and from the morphological changes on the fiber surface and structure from repeated re-slurring. The combination of these effects will affect the actual strength of the fiber, the bonding potential of the fiber and the freeness of the pulp (drainage rate equivalent). By tracking the fiber/bond strength, fiber length and freeness it was determined that Stone Groundwood and Softwood Kraft recycle similarly; although the Kraft pulp showed more significant changes in properties between recycles than the Groundwood. The Softwood Kraft consistently out-performed the Stone Groundwood as expected in physical testing, irrespective of freeness levels.
Liverance, Timothy Clifford, "An Evaluation of Never-Dried Pulp at Multiple Freeness Levels" (1998). Paper Engineering Senior Theses. 297.