3D printer started a manufacturing revolution and is still advancing rapidly. There are robots printing steal bridges, printers printing food and many simple desktop 3D printers that enthusiasts use to produce prototypes or other various things. However, such printers mostly use fossil-based plastics and metals. Now scientists from Chalmers University of Technology have managed to print an object made entirely by cellulose for the first time.
3D printing is extremely attractive and rapidly developing process of manufacturing. That is because designs can become reality pretty fast, no material goes to waste and there is unprecedented freedom of design. But most of the materials used are not organic. Now scientists are using cellulose and other raw materials based on wood to produce three-dimensional objects.
Professor Paul Gatenholm, leader of the research team, explained that “Combing the use of cellulose to the fast technological development of 3D printing offers great environmental advantages”. He also pointed out environmental benefits of the material – “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.”
Unlike other materials used in 3D printing, cellulose does not melt when heated, which raises a big challenge for the scientists. It means, conventional printers cannot be used. Scientists used an interesting approach to solve this problem – they mixed cellulose nanofibrils in a hydrogel consisting of 95-99% water. Then researchers used 3D bioprinter, which was earlier used to produce scaffolds for growing cells, where the end application is patient-specific implants. Of course, since the object was made with a gel that is mostly water, it then had to be dried, which was a challenge in itself.
Drying the printed object is difficult, since the shape has to be maintained for the manufacturing process to be any useful. Scientists froze the object and removed water by variety of different means. They found that they can control the shape, for example, making it lean by controlling drying process.
In further research scientists mixed the cellulose gel with carbon nanotubes, which conduct electricity, to create electrically conductive ink after drying. Using two gels together, one of which is conductive and the other is not, allowed scientists to create three-dimensional circuits, where the resolution increased significantly upon drying. Such integrated circuits would be useful for a variety of applications from sensors integrated with packaging, to textiles that convert body heat to electricity, and wound dressings that can communicate with healthcare workers. Now scientists will try to use all wood biopolymers, besides cellulose.
This is a small scientific advancement in a very popular field of 3D printing. Using biodegradable materials is a crucial part of further success of 3D printing and this research seems to provide good ideas of what these materials could be. Also, scientists are already thinking of improving the process and finding practical applications so we will have to wait and see in what this discovery will develop into.
Source: Chalmers University of Technology via mynewsdesk.com