Durability of wood/plastic composites made from Parthenium species

Previous study indicated that the natural chemical constituents of the guayule plant (Parthenium argentatum) improved some durability properties of wood when it was treated with resin extracted from guayule. At present, there are about a dozen species of Parthenium growing in the North American continent. P. argentatum is the only species with harvestable amounts of the rubber latex. Other species such as P. incanum and P. tomentosum produce primarily resinous materials, but which could be as useful as the P. argentatum species for making composites. The predicted commercialization of guayule for its hypoallergenic latex will result in a significant amount of waste plant material or bagasse that can be put to use in making wood products and would otherwise be a disposal problem. Thus, the guayule fiber residues can be a source of natural wood preservative to improve the durability of wood/plastic composites. Preliminary laboratory tests were conducted to determine the resistance of wood/plastic composites made from three Parthenium species against Eastern subterranean termite. The physical properties of these three types of composites were also measured, namely dimensional stability (water absorption, thickness swelling, two-hour boil, and linear expansion), and the strength properties such as bending and internal-bond (IB) or tensile stress perpendicular to face. The results were compared with a wood/plastic composite made from the commercial pine wood flour or fibers.