Date of Award

Fall 12-4-2019

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Forest Resources

Advisor

Mehdi Tajvidi

Second Committee Member

Douglas J. Gardner

Third Committee Member

Douglas W. Bousfield

Additional Committee Members

William M. Gramlich

Stephen M. Shaler

Abstract

A novel application of cellulose nanofibrils (CNF) as a binding agent is proposed. In this work the utilization of CNF as a complete replacement for the conventional resin-adhesives in the formulation of particleboard (PB) was evaluated. PB panels with varying CNF contents and target densities were produced using a two-step (i.e. cold and hot) pressing process. For initial evaluation, the mechanical and physical properties of the manufactured panels were determined. The need to remove a considerable amount of water from the wood particle (WP)-CNF mixture during cold pressing, motivated the study of the furnish dewatering behavior. Dewatering was assessed through pressure filtration tests, centrifugation, and characterization of hard-to-remove (HR) water. Expressions to predict the dewatering behavior were compared to the results. In search of a cost-effective alternative to the highly refined (90% fines) CNF for the particleboard manufacture, lignin-containing CNF (LCNF) was produced at different fines fractions ranging from 50% to 100%, from recycled old corrugated containers (OCC) as a low-cost precursor. Comparisons of morphology, surface characteristics, turbidity, transparency, tensile and binding properties of the produced LCNF to the CNF at different levels of fines% were made. To investigate the feasibility of producing PB panels with LCNF, a selection of LCNF materials with various fines contents (i.e. 50, 70, 80, and 90%) were used to make the PB panels with the same processing parameters employed to make CNF-bonded PB panels and the physico-mechanical properties of the resulting LCNF-bonded panels were determined. It was found that LCNF 70% is the optimal binder formulation for PB manufacture both technically and economically.

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