A three-year research program at the University of North Texas (UNT) has seen a collaboration of biologists and engineers develop and test a structured insulated panel made from a plant similar to bamboo that could help create greener buildings.

The researchers turned to kenaf, a plant in the hibiscus family, as an attractive prospect because their fibres offer the same strength to weight ratio as glass fibres. They found that the materials using kenaf could provide up to 20 per cent energy savings, reduce energy consumption and reduce overall carbon footprint, compared to fibreglass or steel and Styrofoam products.

Scientists worldwide have begun turning to plants as a resource for biodegradable, renewable and environmentally friendly products and materials that can reduce landfill waste, help the environment and cause little to no damage to natural ecosystems.

Led by UNT’s College of Engineering, the research has been funded by the National Science Foundation with the materials tested in UNT’s Zero Energy Laboratory.

UNT’s Zero Energy Laboratory

The attractiveness of the solution has been further enhanced by the development of a low-cost process by teams in UNT’s Biology and Health Science Departments to prepare the kenaf for use as a building material.

Kenaf is soaked in a microbial solution, and the microbes dissolve everything but the essential plant fibres. This also minimises water absorption and creates a 40 per cent increase in mechanical properties over steam-processing the plant fibres, which is a common alternative used to create other similar plant-based products.

"The development of natural fibre alternatives to fibreglass, and plant-modified structural foam, offers a zero volatile compound option to enable greener buildings," said Nandika D'Souza, a professor of engineering at UNT. "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."

"Plant biologists determined a new method to process grown fibre that materials and mechanical engineers determined had remarkable physical properties and architectures. Construction engineers enabled the building of the housing using the panels."

The team has also been working with industrial partners to help scale up the project.

Kengro, a bioremediation and absorption product manufacturer, has been growing the fibres over multiple acres, while Rubberlite, a rubber and plastic manufacturer, has provided a recycled tire-based structural foam for the panels that led to reduced energy consumption in the zero net energy model.

The next step for the team will be to use the materials in a zero net energy model home construction at UNT's Discovery Park campus.