In an previous article we have seen that nature uses simple basic components but fits them so skillfully together, that quality materials result. Its above all design that makes intelligent materials out of basic ones. We have described how we can use 3d printing and generative design technology with simple materials to create similar complex structures like nature is doing it.
But in order to transition our economy into a circular one, we also need to switch to local resources. A natural material that is locally available in most areas of the world is cellulose. It is the most abundant organic material on earth and is the main basic polymer for plants and trees, also being used for producing paper. Cellulose plays an integral role in keeping the structure of plant cell walls stable. As stability and strength are characteristics that are demanded in human applications, researchers at Desy, a national research center in Hamburg, have produced from cellulose the strongest bio-material that has ever been made. This material is biodegradable but stronger than steel.
The ultrastrong material is made of cellulose nanofibres (CNF). Using a novel production method, called hydrodynamic focussing, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. The process helps to align the nanofibres in the right direction, where the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibers. It’s a change in the nano structure design that enables the strength and stiffness in the polymer. The resulting material even has the potential for biomedicine since cellulose is not rejected by the body. Though it is still in development state, the researchers expect that the material will be ready to use for industrial applications in three to five years, also for 3d printing.
The second most abundant organic material after cellulose is Chitin, the main ingredient in the exoskeletons of beetles, spiders, crabs, and shrimps but also in the cell walls of fungis. Combining these two materials, researchers at the Singapore University of Technology and Design (SUTD) have grown a 3D printable material that is cheap, lightweight, and 100% sustainable.
By introducing controlled amounts of chitin between cellulose fibers, SUTD researchers managed to trigger a fungal-like development of the materials, making them stronger and easier to work with.
The material is producible at scale and no organic solvent is being used, making it completely ecologically sustainable. In order to produce a 1.2 meter turbine blade, the SUTD scientists mixed cellulose and chitin in an industrial dough mixer.
The resulting materials was loaded into an ABB robotic arm, the polymer was used to 3d print the 1.2 meter long turbine blade, weighing just 5.2kg. To make the blade smooth after printing, it was plastered in another layer of FLAM and polished.
FLAM has about the same cost as commodity plastics and is 10 times cheaper than common plastic filaments like ABS and PLA.
SUTD Assistant Professor Javier Gomez Fernandez explains: “We believe this first large-scale additive manufacturing process with the most ubiquitous biological polymers on earth will be the catalyst for the transition to environmentally benign and circular manufacturing models”. The only limitation is that, in general, it is hard to understand for those outside our field the enormous revolution that is coming. We are in the middle of an inflection point in the way we manufacture and our relation with the ecology of earth. It is probably the greatest achievement in the field of bioinspired materials and symbolizes the first example of a technology and material that can challenge the current paradigms in manufacturing.”
The next step for the team is to seek industrial partners who can help bring FLAM to market.