by Staff Writers
Goteborg, Sweden (SPX) Jun 22, 2015
A group of researchers at Chalmers University of Technology have managed to print and dry three-dimensional objects made entirely by cellulose for the first time with the help of a 3D-bioprinter. They also added carbon nanotubes to create electrically conductive material.
The effect is that cellulose and other raw material based on wood will be able to compete with fossil-based plastics and metals in the on-going additive manufacturing revolution, which started with the introduction of the 3D-printer. 3D printing is a form of additive manufacturing that is predicted to revolutionise the manufacturing industry.
The precision of the technology makes it possible to manufacture a whole new range of objects and it presents several advantages compared to older production techniques. The freedom of design is great, the lead time is short, and no material goes to waste.
Plastics and metals dominate additive manufacturing. However, a research group at Chalmers University of Technology have now managed to use cellulose from wood in a 3D printer.
"Combing the use of cellulose to the fast technological development of 3D printing offers great environmental advantages," says Paul Gatenholm, professor of Biopolymer Technology at Chalmers and the leader of the research group. "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.
The breakthrough was accomplished at Wallenberg Wood Science Center, a research center aimed at developing new materials from wood, at Chalmers University of Technology.
The difficulty using cellulose in additive manufacturing is that cellulose does not melt when heated. Therefore, the 3D printers and processes designed for printing plastics and metals cannot be used for materials like cellulose.
The Chalmers researchers solved this problem by mixing cellulose nanofibrils in a hydrogel consisting of 95-99 percent water. The gel could then in turn be dispensed with high fidelity into the researchers' 3D bioprinter, which was earlier used to produce scaffolds for growing cells, where the end application is patient-specific implants.
The next challenge was to dry the printed gel-like objects without them losing their three-dimensional shape.
"The drying process is critical," Paul Gatenholm explains. "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.
Furthermore, the cellulose gel was mixed with carbon nanotubes to create electrically conductive ink after drying. Carbon nanotubes conduct electricity, and another project at Wallenberg Wood Science Center aims at developing carbon nanotubes using wood.
Using the two gels together, one conductive and one non-conductive, and controlling the drying process, the researchers produced three-dimensional circuits, where the resolution increased significantly upon drying.
The two gels together provide a basis for the possible development of a wide range of products made by cellulose with in-built electric currents.
"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," says Paul Gatenholm. "Our research group now moves on with the next challenge, to use all wood biopolymers, besides cellulose.
The research findings are presented this week at the conference "New Materials From Trees" that takes place in Stockholm, Sweden, June 15-17.
The research team members are Ida Henriksson, Cristina de la Pena, Karl Hakansson, Volodymyr Kuzmenko and Paul Gatenholm at Chalmers University of Technology.
Chalmers University of Technology
Space Technology News - Applications and Research
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.|