Interest in wood-plastic composites—commonly used for outdoor decking and indoor molding—is growing as builders look for low-maintenance, rot-resistant materials. One problem: Composite boards are thick and heavy. The bulk increases strength. But a recent development from researchers at Oregon State University's Department of Wood Science and Engineering may allow manufacturers to improve strength while reducing heft.
“Our research has been focused on improvement of interfacial adhesion between wood and plastic, producing lighter and stronger wood-plastic,” explains Kaichang Li, OSU associate professor.
Li created a “compatibilizer,” a polymer that improves the interface between the plastic and the wood. It allows for more stress transfer, increasing strength and stiffness.
Additionally, the compatibilizer will allow manufacturers to use inexpensive plastic material to create a product that “is lighter, stronger, and potentially cheaper.” The cheaper materials include old carpet fibers, about 4.4 billion pounds of which are sent to landfills annually.
Home builders, especially those in areas of the country with drastic climate changes, welcome the innovation. “Wood expands and contracts causing joints to be exposed—composite does not,” explains Bob McLemore, president of HouseRaising in Charlotte, N.C. The company manages projects from design and cost estimation to construction for affiliated builders. “Porch columns, siding, and large interior moldings perform better as composite materials for the same reason.”
The OSU product has only been tested in the lab, but Li and his team will soon test their composite on a near-industrial scale.
Margot Carmichael Lester is a freelance writer based in Carrboro, N.C.
Learn more about markets featured in this article: Charlotte, NC.