Plant Cellulose – Stiffness of Steel
Recent scientific findings that unveil the remarkable structural performance of plants could completely change what we think of a “green architecture.” Researchers at Purdue University, who conducted an experiment on cellulose nanocrystals concluded that the material, which is the structural basis of plant life, has the stiffness of steel. The same tiny cellulose crystals that give trees and plants their high strength, light weight and resilience, have now been shown to have the stiffness of steel. The nanocrystals might be used to create a new class of biomaterials with wideranging applications, such as strengthening construction materials and automotive components.
Cellulose can be found in plants, vegetables, algae, some marine organisms and bacteria. According to a recent experiment conducted at Purdue University in Indiana, this biomaterial could be the ultimate renewable resource, particularly since it is so abundant and produced as waste in the paper and food industry. Cellulose nanocrystals are a potential alternative to carbon nanotubes, polymers and concrete. When the researchers tested cellulose nanocrystals during the Purdue experiment, they found that this seemingly fragile material is only 500 nanometers long, but exhibits the remarkable stiffness of 206 gigapascals – the same as steel. Because of tiny samples sizes, testing this material was impossible in the past. The nanocrystals are about 3 nanometers wide by 500 nanometers long – or about 1/1,000th the width of a grain of sand – making them too small to study with light microscopes and difficult to measure with laboratory instruments. This time the scientists used quantum mechanics to unlock the super material’s potential, a scientific breakthrough that could open the door to a future in which all architecture could mimic the structural performance and behavior of plants. The findings represent a milestone in understanding the fundamental mechanical behavior of the cellulose nanocrystals.
“It is very difficult to measure the properties of these crystals experimentally because they are really tiny,” said Pablo Zavattieri, a Purdue University assistant professor of civil engineering. “For the first time, we predicted their properties using quantum mechanics.”
“It is also the first step towards a multiscale modeling approach to understand and predict the behavior of individual crystals, the interaction between them, and their interaction with other materials,” Zavattieri said. “This is important for the design of novel cellulose-based materials as other research groups are considering them for a huge variety of applications, ranging from electronics and medical devices to structural components for the automotive, civil and aerospace industries.”
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Materials provided by the School of Civil Engineering, Purdue University