Researchers from Singapore University of Technology and Design have demonstrated 3D printing with one of the Earth’s most abundant organic compounds: cellulose.
Instead of going with the cellulose associated with green plants, however, the sustainable manufacturing method reproduces the walls of fungus-like oomycetes, which, in addition to cellulose, contain the fibrous substance chitin.
By introducing chitin within the cellulose fibers, the SUTD researchers created a fungal-like reaction.
The result: FLAM!
Or more specifically: Fungal-like Adhesive Materials. The strong, lightweight, and biodegradable FLAM can be molded or processed using woodworking techniques.
No organic solvents or synthetic plastics are required to manufacture the material.
“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, where materials are produced, used, and degraded in closed regional systems,” said UTD Assistant Prof Javier Gomez Fernandez.
Fernandez spoke with Tech Briefs about what kinds of 3D-printed objects can be made with the fungal-like adhesive materials.
Tech Briefs: What inspired you to do this work?
Prof. Javier Gomez Fernandez: We have been working in this direction for the past 6 years. While I was working in Harvard, we hypothesized that natural molecules and the way they arrange in living organisms to form structures are two sides of the same coin.
Taking the oomycetes’ wall as inspiration, we developed FLAM and the technique to fabricate with it in a holistic manner.
Tech Briefs: Why did you choose the oomycete for inspiration?
Prof. Fernandez: The technique, in contrast to regular 3D printing, has a fine control of parameters such as pressure, water content, or pH, which are crucial for natural materials but irrelevant for plastic. We chose the oomycete wall as a target because it is one of the few biological structures where the two most abundant organic components on earth (cellulose and chitin) are used to form strong structures.
Tech Briefs: What exactly is the Fungal-Like Adhesive material?
Prof. Fernandez: The material is a composite of cellulose and chitosan in a 8:1 ration (i.e,. almost 90% of the composite is cellulose). It is made by dispersing cellulose fibers in a chitosan solution in 1% acetic acid. We then remove the water based solution in a controlled manner. During this process, the chitosan forms a crystal structure intermingled with the cellulose.
Tech Briefs: How is this process different from previous attempts at 3D printing with cellulose?
Prof. Fernandez: What is very important and different from previous claims of 3D printing cellulose is that we don’t modify the natural molecules. Previous attempts have been focused on trying to modify cellulose to be more “plastic like,” producing Rayon or cellulose acetate, and dissolving them in acetone or carbon disulfide. All these processes are extremely harmful and environmentally unfriendly; that is why they never were explored outside labs. Our process can be reproduced in a kitchen.
Instead of trying to transform the molecule in something we know how to work with, we study natural systems to understand and reproduce the way to work with the biological molecules, without modifications.
Tech Briefs: Why is cellulose such a great material to use for 3D printing?
Prof. Fernandez: Cellulose, similar to chitin, is not only the most abundant organic molecule on earth, it is also the most ubiquitous, and can be found in large amounts almost anywhere. 3D printing with cellulose, without chemical modifications, is therefore the catalyst for circular economy, where we would only need an electric plug to manufacture. All the material is produced, manufactured, and degraded in a closed regional system.
More importantly, in the U.S., for example, 14% of the municipal waste is wood, while industries such as agriculture, food, textile, and paper produce a high amount of waste with high cellulose content. We have demonstrated that we can 3D print any cellulosic byproduct, independently of its origin. We can, for example, transform your old cotton t-shirts into a coffee table or your old coffee table in a different one.
Also, differently from previous attempts to manufacture with cellulose, all the process is completely sustainable and doesn’t require any solvent, and all the products are 100% biodegradable in months and in your backyard, outside composting facilities.
Tech Briefs: What kinds of products can be made?
Prof. Fernandez: Currently we are producing from bowls to turbine blades, but our next objective is to aim for much larger structures.
Tech Briefs: Are there limitations to the material that limit what can be made?
Prof. Fernandez: The material is fully biodegradable, and that — depending on the application — might be a limitation. For example, similar to timber, it changes when submerged in water for extended periods of time. Similar to timber, however, we have coated/painted FLAM objects to make them water resistant.
Tech Briefs: How do you envision this being used in the future?
Prof. Fernandez: We aim to regionalize big parts of the global production, and we believe we have just developed the technology necessary for that. We can finally and globally move towards circular and sustainable manufacturing models. We developed an additive manufacturing system for the material because we want a manufacturing technique of great versatility at the cost of large-number production. We envision that a technique with these characteristics can be used to produce on-demand in regional manufacturing facilities, supplying consumer goods to a specific region from where the facility also receives the resources to manufacture.
What do you think? Do you see cellulose as a valuable 3D-printing material? Share your thoughts and questions below.