Selected Properties of Wood Strand and Oriented Strandboard From Small-Diameter Southern Pine Trees

Authors

  • Guangping Han
  • Qinglin Wu
  • John Z. Lu

Keywords:

Southern pine, small diameter, strand, OSB, property, fines

Abstract

Thermal and mechanical properties of southern pine and willow strands and properties of southern pine oriented strandboard (OSB) from small-diameter logs were investigated in this study. The effects of density and species group on tensile strength, dynamic moduli, and thermal stability of wood strands, and of strand quality (i.e., wood fines) on three-layer OSB properties were analyzed.

Strand tensile strength and dynamic storage moduli (E') increased with the increase of strand density. A large variation in both tensile strength and E' values was observed for southern pine, while willow strands showed much smaller variability. The dynamic moduli (E") of strands decreased with increase of temperature in the range of 25° to 200°C. Small loss modulus (E") peaks were observed over the temperature range studied. The strands with higher densities had higher E". Thermogravimetric analysis results revealed that high-density strands were thermally more stable than low-density strands.

Three-layer OSB made of small-diameter southern pine trees showed satisfactory strength and dimensional stability properties. As the fines loading levels increased, linear expansion (LE) along the parallel direction decreased, while the LE value along the perpendicular direction and thickness swelling increased. With increased fines levels, the internal bond strength showed an increasing trend up to the 20% fines level, and bending strength and modulus varied little in the parallel direction and slightly decreased in the perpendicular direction.

References

American Society for Testing and Materials (ASTM). 1998. Annual book of ASTM standard D1037-96. ASTM. Philadelphia, PA. 646 pp.nAlen, R., E. Kuoppala, and P. Oesch. 1996. Formation of the main degradation compound groups from wood and its components during pyrolysis. J. Anal. Appl. Pyrolysis36:137-148.nAlen, R., R. Kotilainen, and A. Zaman. 2002. Wood Sci. Technol.36:163-171.nBackman, A. C. 2001. Differences in wood material responses for radial and tangential direction as measured by dynamic mechanical thermal analysis. J. Mat. Sci.36:3777-3783.nBakker, R. R., R. J. A. Gosselink, R. H. W. Maas, T. De Vrije, and E. De Jong. 2004. Biofuel production from acid-impregnated willow and switchgrass. 2nd World Conference for Energy, Industry and Climate Protection, 10-14 May 2004, Rome, Italy. Pp. 1467-1470.nBarnes, D. 2000. Integrated model of the effect of processing parameters on the strength properties of oriented strand wood products. Forest Prod. J.50(11/12):33-42.nBarnes, D. 2001. A model of the effect of strand length and strand thickness on the strength properties of oriented wood composites. Forest Prod. J.51(2):36-46.nBendtsen, B. A. 1978. Properties of wood from improved and intensively managed trees. Forest Prod. J.28(10):61-72.nElder, T. 1990. Pyrolysis of wood. Pages 665-699 in D. N. S. Hon and N. Shiraishi, eds. Wood and cellulosic chemistry. Marcel Dekker, Inc., New York, NY.nEngineered Wood Research Foundation (EWRF). 2001. OSB fines grant—request for proposal. EWRF, Tacoma, WA.nFuruta, Y., M. Makinaga, H. Yano, and H. Kajita. 1997. Thermal-softening properties of water swollen wood II. Anisotropic characteristics of thermal softening properties. Mokuzai Gakkaishi43(1):16-23.nGeimer, R. L. 1976. Flake alignment in particleboard as affected by machine variables and particle geometry. Res. Paper 275. USDA, Forest Prod. Lab., Madison, WI.nGeimer, R. L., J. Mahoney, S. P. Loehnertz, and R. W. Meyer. 1985. Influence of processing-induced damage on strength of strands and strandboards. Research Paper FPL-463. USDA Forest Service, Forest Prod. Lab., Madison, WI. 15 pp.nKretschmann, D. E., R. C. Moody, R. F. Pellerin, B.A. Bendtsen, J. M. Cahill, R. H. McAlister, and D. W. Sharp. 1993. Effect of various proportions of juvenile wood on laminated veneer lumber. Research Paper FPL-RP-521. USDA Forest Prod. Lab., Madison, WI. 31 pp.nKelly, M. W. 1977. Critical literature review of relationships between processing parameters and physical properties of particleboard. Gen. Tech. Rep. FPL-GTP-10. USDA-forest Serv., Forest Prod. Lab., Madison, WI. Pp. 4-16.nLee, J. N., and Q. Wu. 2003. Continuum modeling of engineering constants of oriented strandboard. Wood Fiber Sci.35(1):24-40.nLeVan S. L. 1989. Thermal degradation. Pp. 271-273 In A. P. Schniewind, ed. Concise Encyclopedia of Wood & Wood-Based Materials. Pergamon Press, Exeter, England.nPrice, E. W. 1975. Determining tensile properties of sweetgum veneer flakes. Forest Prod. J.26(10):50-53.nPearson, R. G., and R. C. Gilmore. 1971. Characterization of the strength of juvenile wood of loblolly pine. Forest Prod. J.21(1):23-30.nRowell, R. M., and W. B. Banks. 1987. Tensile strength and toughness of acetylated pine and line flakes. British Polymer J.19:478-482.nSalmen L. 1984. Viscoelastic properties of in situ lignin under water-saturated conditions. J. Mater. Sci.19:3090-3096.nShafizadeh F. 1985. Pyrolytic reactions and products of biomass. Pages 183-217 in P. P. Overend, T. A. Milne, and L. K. Mudge, eds.: Fundamentals of Thermalchemical Biomass Conversion. Elsevier, New York, NY.nSmulski, S. 1997. Engineered Wood Products—A guide for specifiers, designers and users. PFS Research Foundation. Madison, WI.nUSDA Forest Products Laboratory (FPL). 1999. Wood handbook—Wood as an engineering material. Gen. Tech. Rep. FPL-GTR-113. USDA Forest Serv., Forest Products Lab. Madison, WI. 463 pp.nWolfe R. 2000. Research challenge for structural use of small-diameter round timbers. Forest Prod. J.50(2):21-29.nWu, Q., Z. Cai, and J. N. Lee. 2005. Tensile and dimensional properties of wood strands made from plantation southern pine lumber. Forest Prod. J.52(2):1-6.nWu, Q., Z. Cai, G. Han, and J. N. Lee. 2006. Tensile and thickness swelling properties of flakes from southern hardwood and southern pine: effect of hot pressing and resin application. Forest Products J. In-press.n

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Published

2007-06-05

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Research Contributions