A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Engineering in Pulp and Paper Technology

Thesis (M.Eng.) - Asian Institute of Technology, 2007

This thesis is based on the study of frayed fiber. A softwood pulp (mixture of hemlock and pine) was refined in the range of 200-450 kWh/t using specific edge load of 3w.s/m. The pulp then was examined visually for frayed fiber using magnifying microscope. The population of frayed fiber was increased with the increase of refining energy, although the population of the frayed fiber was much less than expected due to the shorter fiber length and smaller coarseness of the unrefined pulp (i.e., the original pulp). The resolution of the microscope was very low, so the details of the frayed fiber was not observed, however, fibers by similar characteristics of frayed fibers was visible with the microscope or naked eye as compared with the control fibers. The refined pulp was examined for pulp characteristics and papermaking quality. Fiber length and fiber coarseness were reduced, but the fines percentage of the pulps were increased. All strength and optical properties were increased except zero-span tensile strength. R30 fraction of the most refined pulp (i.e., pulp refined to 450kWh/t) was assumed to represent frayed fiber. Different percentage of the frayed fiber was mixed with Eucalyptus pulp refined in PFI mill to 4000 revs. The result compared with the pulp refined to 300 kWh/t using Escher Wyss. It was concluded that the papermaking quality of the fine paper made using frayed fiber well competes with the whole refined pulp (i.e., pulp refined to 300kWh/t). Frayed fiber as a reinforced pulp also shows better drainage, air permeability and bulk, which are critical factors in many papermaking applications.