Pressure’s On

High-strength building products

It was a great idea, just ahead of its time. More than 50 years ago, engineers came up with a way to increase the strength and stiffness of wood. By applying steam, heat and pressure, they increased strength by about 250 percent. Problem was, strong wood was in plentiful supply. So, except for some minor applications, the technology languished.

But that is changing.

Fred Kamke, professor in the OSU Department of Wood Science and Engineering, has now improved the process, achieving strength increases up to 400 percent, taking less time and using less mechanical force. He has applied for a patent on the technique, known as viscoelastic thermal compression, or VTC. The strength and stiffness of VTC wood is better than the best available Douglas fir.

This time around, the stars may be aligned for wood processed in this manner. Demand for wood products is rising, and supplies of high-strength timber are dropping. “When you can find it, you pay a high price for it,” says Kamke, who holds the JELD-WEN Chair in Wood-Based Composites Science at OSU.

In the Northwest, opportunity knocks on thousands of acres of fast-growing hybrid poplar. Oregon has about 20,000 acres, originally intended for the pulp and paper industry. Now, the low price of pulp has landowners looking for a more valuable way to use the wood. But hybrid poplar is weak, as useful as jelly for load-bearing structural components.

Kamke has used the VTC process to create a high-strength hybrid poplar composite. “The VTC wood is strategically placed where needed most in the composite. It may be bonded to ‘normal’ wood, which more or less acts as a filler,” says Kamke.

Businesses are now showing interest in using VTC wood materials in new wood products. “I can see uses for it in building construction, and I think there could be applications for flooring materials because it has good hardness properties,” Kamke adds.

In addition to VTC technology, Kamke studies wood adhesives, a critical element of engineered wood composites. Despite thousands of years of experience with wood glues (starting with the ancient Egyptians), the chemical and physical details of how they work are poorly known. Better understanding, Kamke adds, could pave the way for stronger and more durable building products.

Wood composites are the fastest growing segment of the forest products industry. Through its endowment, Klamath Falls-based JELD-WEN (the country’s second-largest window and door manufacturer) has shown its commitment to helping Oregon take advantage of that trend. “JELD-WEN values research and innovation and has a long history of working with and supporting Oregon State,” says Kamke.

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