Date of Award
Bachelor of Science
Paper Science and Engineering
Although wood has remained the dominant raw material for papermaking since the late 19th century, a number of recent financial and environmental contingencies have reverted attention back to the possible utilization of non-wood fibers for papermaking purposes. In particular, recycling remains an omnipresent facet of the forest products industry. Studies indicate that kenaf provides the greatest potential as a papermaking crop within the United States and can be employed to produce high-quality newsprint, and kenaf utilization provides a number of inherent and environmental benefits. Because the CTMP process produces the most functional kenaf pulp; this study of the effects of recycling on kenaf bast CTMP handsheets was conducted to establish trends and help determine the feasibility of incorporating kenaf fibers into recycled paper grades.
After some kenaf bast CTMP was received from Mr. John Stahl of The Evanescent Press, the stock was dispersed using a valley beater and screened via a six-cut screen. Virgin handsheets were then created using the Noble and Wood apparatus, and some of those sheets were conditioned and tested for density, burst index, breaking length, scattering coefficient, brightness, folding endurance, and tear force. The remaining sheets were repulped using the valley beater, and this process was completed through four levels of recycling. Finally, two samples of recycled pulp were refined to different freeness levels using a PFI mill. The resultant pulp was used to create, condition and test handsheets as well.
As expected, the directions of change of kenaf bast CTMP handsheet properties during recycling mimic those of chemical wood sheets: as burst index, breaking length, folding endurance, and density decrease, the tear force, scattering coefficient, and brightness increase. However, the magnitude of these changes far exceeds those of chemical wood sheets. Fortunately, refining the kenaf bast CTMP not only retrieves lost strength properties, but maintains the improved values of properties that showed increases. In general, kenaf will be utilized primarily as a reinforcement pulp. Assuming that most recycling procedures employ a refining stage, the appropriation of kenaf into recycled paper streams should increase recycled sheet quality and possibly facilitate quality control and efficiency of recycled paper operations.
Willoughby, David B., "The Effects of Recycling on Kenaf Handsheet Properties" (1998). Paper Engineering Senior Theses. 572.