DENTON, Texas — After three years of research, experts at the University of North Texas (UNT) believe they have found a plant-based material that is cost-efficient to manufacture and capable of significantly reducing energy consumption.
Researchers at UNT developed and tested structured insulated panel building materials made from kenaf, a plant in the hibiscus family that is similar to bamboo. Kenaf fibers are an attractive prospect because they offer the same strength to weight ratio as glass fibers.
Kenaf materials, including composite panels, provide up to 20 percent energy savings and reduce energy consumption and overall carbon footprint compared to fiberglass or steel and Styrofoam products.
“The development of natural fiber alternatives to fiberglass, and plant-modified structural foam, offers a zero volatile compound option for home, automotive and consumer applications,” said Nandika D’Souza, a professor in UNT’s College of Engineering and leader of the study, in a statement.
The study was made possible through grant funding from the National Science Foundation. UNT used its Zero Energy Laboratory to test kenaf and other sustainable building materials and technologies. Opened in 2012, the lab is a 1,200-square-foot facility that offers hands-on experience with testing alternative energy technologies and how they can produce enough energy to power a building.
A low-cost process to prepare kenaf for use as a building material was developed by UNT Associate Professor of Biology Brian Ayre and University of California Riverside Professor of Biology Michael Allen. The process involved using a microbial solution to extract and prepare plant fibers. Kenaf is soaked in the microbial solution, and the microbes dissolve everything but the essential fibers.
Researchers found that using the microbial solution minimized water absorption and created a 40 percent increase in mechanical properties over steam-processing the plant fibers, which is a common alternative used to create other plant fiber products.
The work to study kenaf is a project in the Farmer-Academic-Industry Partnership for the Development of Sustainable, Energy Efficient, Multifunctional Bioproducts for the Built Environment.
The team also worked with industrial partners as part of the National Science Foundation's Partnership for Innovation program. Kengro, based in Charleston, Miss., is a bioremediation and absorption product manufacturer, and Rubberlite, based in Huntington, W. Va., is a rubber and plastic manufacturer. Kengro grew fibers over multiple acres to help increase the scale of the project, and Rubberlite provided a recycled tire-based structural foam for the panels that led to reduced energy consumption in the net zero energy model.
“None of this would have been possible without the collaboration of our interdisciplinary team of plant biologists; construction engineers; and materials, mechanical and energy engineers and their collective recognition of, and contribution to, the intellectual value of this work,” D’Souza said. “Plant biologists determined a new method to process grown fiber that materials and mechanical engineers determined had remarkable physical properties and architectures. Construction engineers enabled the building of the housing using the panels.”