A tiny chair made of wood cellulose was made using a 3-D bioprinter. Photo by Chalmers University of Technology
STOCKHOLM, Sweden, June 17 (UPI) -- Researchers in Sweden have developed a 3-D printer capable of building objects out of cellulose from wood. The scientists say plant-derived biomaterials could soon rival fossil-based materials like plastic and metal in additive manufacturing.
Additive manufacturing, or 3-D printing, is the process of building objects from the ground up -- accreting material as opposed to deleting material. Traditional manufacturing would see a baseball bat carved from a large block of wood. Additive manufacturing might stack layers of cellulose to form the bat, minimizing waste.
Most first-generation 3-D printers employ plastic because it's easiest to work with. Both plastics and metals melt and high temperatures and become easily malleable, allowing the precise robotic arms of a 3-D printer to shape and layer the material into form.
Now, researchers at Chalmers University of Technology have found a way to use biomaterials like wood cellulose to print 3-D objects.
"Combing the use of cellulose to the fast technological development of 3D printing offers great environmental advantages," lead researcher Paul Gatenholm said in a press release. "Cellulose is an unlimited renewable commodity that is completely biodegradable, and manufacture using raw material from wood, in essence, means to bind carbon dioxide that would otherwise end up in the atmosphere."
Biomaterials like cellulose don't melt like plastics, so researchers had to find a way to make them malleable. To do so, the scientists suspended cellulose nanofibrils in a water-based gel. Researchers then had to find away to dry the 3-D printed gelatin object without causing it to collapse.
"The drying process is critical," Gatenholm explained. "We have developed a process in which we freeze the objects and remove the water by different means as to control the shape of the dry objects. It is also possible to let the structure collapse in one direction, creating thin films."
Gatenholm was also able to integrate carbon nanotubes into the gel, allowing the construction of cellulose objects capable of conducting electricity.
"Potential applications range from sensors integrated with packaging, to textiles that convert body heat to electricity, and wound dressings that can communicate with healthcare workers," said Gatenholm. "Our research group now moves on with the next challenge, to use all wood biopolymers, besides cellulose."
The researchers recently shared their new technology with attendees at this week's "New Materials From Trees" conference in Stockholm.
