Wood Plastic Composites with Tennessee Species
Wood Plastic Composites (WPCs) are mixtures of plastic and wood flour that can be made into various products. The most common example is the decking boards that are widely available as substitutes for treated wood. Common brand names include Trex, ChoiceDek and Eon.
WCPs use about 50% wood as a filler to lighten and stiffen the finished product. Wood is also cheaper than plastic, so the wood filler reduces the final cost. However, the properties of the wood itself generally are not an important consideration. Maple and pine are the most commonly-used species because they are widely available and inexpensive.
Tennessee is home to a wide variety of species with interesting properties. Some examples are Osage orange, cherry, black walnut and red cedar, each of which has significant natural resistance to rot and insect attack. Recent research at UT has examined the possibility of using these different wood species in WPCs.
It turns out that structurally-sound WPCs can be made using any of the species tested. However, the WPCs made with cherry, cedar and Osage orange had superior properties in terms of not absorbing water and swelling and their resistance to mold and rot. This isn't too surprising – it's simply a matter of the inherent wood properties being passed on to the WPCs.
Tennessee has abundant forests with diverse wood species. These wood species have many interesting properties. By taking advantage of the inherent properties of the wood in new products such as WPCs, we can make better products.