Chapter 25
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Wood Composite Protection Douglas J. Gardner, Cihat Tascioglu, and MagnusE.P. Wålinder Advanced Engineered Wood Composites Center, University of Maine, Orono, ME 04469
Wood composites should be protected against microbial and insect attack when used outdoors, especially in construction applications with prolonged exposure to moisture. Preservative systems and treatment processes affect composite properties, especially adhesive/wood bonding and mechanical properties. Several common systems for preservation of composites include: 1) the use of pretreated wood, applicable particularly to some solid lumber laminates; 2) in-process preservative treatments favored for composites made from flakes, particles, andfiberswhere the preservative treatment is incorporated during the manufacturing process; 3) postprocess preservative treatments which are generally favored for wood composites madefromlumber and veneer; and 4) the use of recycled treated wood elements in manufacturing or the use of wood species with a high natural resistance against biodegradation. This chapter discusses these four preservative methods and presents a general overview of current research concerning preservation practices and techniques in North America including the effect of preservatives on composite properties, durability issues, and degradation modes.
© 2003 American Chemical Society In Wood Deterioration and Preservation; Goodell, B., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2003.
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Introduction The production of wood-based composites has increased dramatically over the past three decades due to a number of factors including the changing wood supply, development of new composite technologies, and the widespread acceptance by architects and builders of wood composites for use in construction. Depending on the particular application, wood composites require protectionfromthe effects of moisture, weather, biological infestation (decay, insects, marine borers), andfire.It must be emphasized, however, that decay problems are in most cases a result of faulty design or construction, incorrect installation, lack of reasonable care in the handling of the wood, or improper maintenance of the structure (i). In fact, with a good design, including applications of surface coatings and the addition of wax, some wood composites, such asfiberboard,have been utilized for several decades as exterior siding with good results. The preservation or protection of wood composites is a topic that continues to receive considerable attentionfromresearchers and manufacturers (2, 3). The public perception of wood composites is both good and bad Unfortunately, much of the recognition of wood composites in the popular media has centered on class action lawsuits resultingfromproduct failures such as the thermal degradation offire-retardanttreated plywood (4) and the oriented strandboard siding failures (J). The topic of wood composite protection remains important as the impact of energy efficient construction practices (
