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Abstract
Loblolly pine chips, separated into mature and juvenile portions, were refined at three pressures (4, 8, and 12 bar) in a single disc refiner at the BioComposites Centre. Fibres were dried in a flash drier to a moisture content of approximately 12 percent. The mechanical properties of single fibres from each refining pressure were determined using a tensile strength tester. The tensile tester is a custom-built screw-driven cross-head fitted with a 5 Newton-capacity load cell. Fibres were tested at an elongation rate of 80 microns/minute. Load-elongation traces were converted to stress-strain curves with tensile span and cross-sectional area. Tensile span was measured as cross-head movement and was approximately 1mm. The cross-sectional area of each tested fibre was measured using confocal microscopy. Fibre modulus of elasticity and ultimate tensile stress were then detelmined from the stress-strain curves. Fibre stiffness and strength were further studied to evaluate their effect on structural fibreboard panels. Small MDF panels were prepared with a urea-formaldehyde adhesive at an addition level of 12 percent solids to determine this effect. The dimensions of the mini-panels were 100 x 125 x 3mm The panels were tested for MOE, MOR and internal bond strength. Correlations were then drawn between fibre and subsequent panel properties.
Citation
Groom, Les; Rials, Timothy; Snell, Rebecca. 2000. Effects of varying refiner pressure on the machanical properties of loblolly pine fibres. Proceedings of the Fourth Panel Products Symposium, Llandudno, Wales UK, October 11-13, Hague; Griffiths; McLauchlin; Mayhead; Skinner; Tomkinson, eds.
