A group of scientists are doing their best to create new applications of bio-material for cellulose-based components for 3D printing applications that will replace raw materials derived from fossil. The project is called the Design Driven Value Chains in the World of Cellulose (DWoC) 2.0 project. The VTT Technical Research Centre situated in Finland. This government programme focuses on the importance of bioeconomy. Vice-president of Research at VTT Johanna Buchert said that that constant renewal demands huge leaps in research, taking risks and needing national investment innovation and research. Wood is called the green gold of Finland, it is renewable material. Wood cellulose can be a good opportunity when they come up with applications of high value, all along with traditional pulp and paper industry.
During the first phase of the project the team hopes to find the methods how to combine materials and designs; and a wide range of such formulations were considered and tested. The project resulted in some of the product ideas like making threads from pulp fiber suspensions. Such a product immediately came into production stage, when it has been rolled out this year by Spinnova.
It may also be textile applications for 3D printing of cellulose which looks more promising. What especially drives 3D production methods are designs. The potential of the technology to produce small amounts of products in an economical and flexible way is based on using two main kinds of plastic – PLA and ABS. The work carried out in Finland is aimed at extending the available range of colours by finding and creating more renewable materials. The Finns are working to investigate the compatibility of 3D FDM printing with the cellulose-based raw materials applying thermoplastic cellulose by-products.
For the first trials materials processing at low temperatures have been chosen. However the pure cellulose by-products showed poor results during tests. But it was the insufficient layer adhesion that they blamed. So they increased the quality of the material via plasticization, which simultaneously lowered melt ductility and reduced glass transaction temperature. Layer sticking and general performance were upgraded to such a degree that 3D strictures could be developed from the thermoplastic cellulose by-product.
Tiia-Maria Tenhunen, Tuomas Hänninen and Marjaana Tanttu from Aalto University developed the concepts, whose purpose was to create “multifunctional pattering” for sportswear fabrics. Their work became part of Master’s thesis in Textile Art and Design. According to the team, the possible applications succeeded in developing self-standing things and 3D printed surface constructions on textiles and other underlying layers. To do this they used the method of direct-write 3D printing (the nScrypt). The method is a kind of process based on extrusion that uses paste-like materials distributed via the syringe pump system. The Alto team says that such a technique will allow for a wider range of various materials to be 3D printed – cellulose based plastics, pulp fibers composites, and hydrogels.
The structures of “cellulosic hydrogel” were developed with cellulose diluted in ionic liquid or using hydrophilic oxidized nanocellulose. Such structures can be kept in extremely humid conditions. The hydrogels can also be used for creating very porous, aerogel-like things. A hard-cellulose product may be printed and dried soon in the air with a small percentage of shrinkage. The Aalto group also says that products of soft cellulose were most suitable to develop flexible structures and to make prints on textile. Being part of the process, colorants and pulp fibers were mixed with hard and soft cellulose products to help develop fibrous complex materials. Each of the materials looked and felt absolutely different.
The team 3D printed the hard or soft structures, fragile and strong, pliant and stiff, thick and spongy. They can be straight printed either on textiles or on substrates. As part of the demonstration the researchers used the soft cellulose product to create a string of pearls. In this product they added a mixture of 10% cellulose fibers into the soft cellulose product.
This study may lead to a great variety of new applications for 3D printing. If you have ever considered trying cellulose-based materials for some 3D printing project, go ahead!