28 Mai 2004

Opportunities and Challenges for Wood-Plastic Composites in Structural Applications

In response to consumer demands for low maintenance and durable timber construction and increased environmental regulation of preservative treated lumber, the wood-plastic composite (WPC) industry in North America and Asia has emerged in the last decade. These composite materials are produced by combining thermoplastic polymers with natural fibers derived from wood and agricultural crops. Complex structural sections can be formed using adaptations of conventional plastics processing techniques.

The retail value of this industry is growing nearly 16 percent annually since 1998; currently valued at over $0.75 billion. While primarily focused on residential products such as exterior decking, railing, doors, and windows, the industry has the opportunity to expand into a host of new products, including structural components for housing, marine, and transportation structures. Opportunities also exist in the development of structural components used to connect different structural systems in low-rise buildings. Structural components that simultaneously resist moisture intrusion and high loads arising from lateral forces present particular opportunity. To reach these product goals, current versions of wood-plastic composites are presented with certain challenges in performance and product design. Formulations with a variety of polymer types are sufficiently strong to resist the loads expected in many structural applications; however, improvements are necessary in both long-term bad performance and product weight. Consumer acceptance of hollow sections used to optimize structural performance is necessary. Alternatively, commercial foaming practices must be advanced to lower product density while maintaining solid cross-sections.

Higher structural uses of wood-plastic composites present a beneficial market opportunity to expanding the current decking dominated market for these materials. Such systems will likely add improvements to both new and existing products. Exterior structural applications such as marine, transportation, and deck structures are likely initial markets. However, engineered members to fill the growing need for seismic resistance are possible.

Although static mechanical properties of a variety of polyolefin-based formulations are more than adequate for many products, certain weakness in current products must be improved to realize these new applications. In particular improved long-term bad performance and reduced product weight will be necessary.

Comment: The “Progress in Woodfibre-Plastic Composites” Conference 2004 in Toronto (Canada), May 10-11, 2004, was organized by the University of Toronto. 400 participants from many different countries attented the conference.

(Vgl. Meldung vom 2003-12-09.)

Source: Opening lecture "Progress in Woodfibre-Plastic Composites", Toronto, May 10-11. Michael P. Wolcott (Washington State University) and Paul M. Smith (Pennsylvania State University).

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