University 3D Prints Green Architectural Materials
A hydrogel material formed from nanocellulose and algae has been tested for what considered the first time as an alternative, more sustainable building material at Chalmers University of Technology in Gothenburg, Sweden.
The study, from the university and the Wallenberg Wood Science Center, reportedly shows how the green material can be 3D printed into a variety of architectural components, using less energy than traditional construction methods.
The research was recently published in the journal Materials and Design.
About the Materials
According to Chalmers, the construction industry today consumes 50% of the world’s fossil resources, generates 40% of global waste and causes 39% of global carbon dioxide emissions.
While nanocellulose is not a new biomaterial, it is typically used in the field of biomedicine in its hydrogel form, where it can be printed into tissue and cell growth due to its biocompatibility and wetness. The university notes that it has never been dried and used as a building material.
This process was first developed by the university in 2015; however, this is the first time that the technology is being scaled up to building applications.
“For the first time we have explored an architectural application of nanocellulose hydrogel. Specifically, we provided the so far missing knowledge on its design-related features, and showcased, with the help of our samples and prototypes, the tuneability of these features through custom digital design and robotic 3D printing,” said Malgorzata Zboinska, lead author of the study from Chalmers University of Technology.
For the research, the team reportedly used nanocellulose fibers and water, with the addition of an algae-based material called alginate. The alginate allowed the researchers to produce a 3D printable material, since the alginate added an extra flexibility to the material when it dried.
Cellulose is coined as the most abundant eco-friendly alternative to plastic, as it is one of the byproducts of the world’s largest industries, Chalmers adds.
“The nanocellulose used in this study can be acquired from forestry, agriculture, paper mills and straw residues from agriculture. It is a very abundant material in that sense,” said Zboinska.
As building standards shift towards more sustainable practices, the architectural industry must look at methods such as reuse and recycling of materials, as well as more circular digital technologies, according to the researchers.
“3D printing is a very resource efficient technique. It allows us to make products without other things such as dies and casting forms, so there is less waste material. It is also very energy efficient. The robotic 3D printing system we employ does not use heat, just air pressure. This saves a lot of energy as we are only working at room temperature,” explained Zboinska.
The energy efficient process reportedly relies on the shear thinning properties of the nanocellulose hydrogel. When pressure is applied, the product liquifies, allowing it to be 3D printed. When that pressure is removed, the product maintains its shape. This, the researchers say, allows them to work without the energy intensive processes that are commonplace in the construction industry.
Zboinska and her team reportedly designed many different toolpaths to be used in the robotic 3D printing process to see how the nanocellulose hydrogel would behave when it dried in different shapes and patterns.
These shapes could then be applied as a basis to design a wide array of architectural standalone components, such as lightweight room dividers, blinds, and wall panel systems.
Additionally, they could form the basis for coatings of existing building components, such as tiles to clad walls, acoustic elements for damping sound, and combined with other materials to clad skeleton walls.
“Traditional building materials are designed to last for hundreds of years. Usually, they have predictable behaviors and homogenous properties. We have concrete, glass and all kinds of hard materials that endure and we know how they will age over time. Contrary to this, biobased materials contain organic matter, that is from the outset designed to biodegrade and cycle back into nature,” said Zboinska.
“We, therefore, need to acquire completely new knowledge on how we could apply them in architecture, and how we could embrace their shorter life cycle loops and heterogenous behavior patterns, resembling more those found in nature rather than in an artificial and fully controlled environment. Design researchers and architects are now intensely searching for ways of designing products made from these materials, both for function and for aesthetics.”
According to the university, the study provides the first steps of demonstrating the potential of upscaling ambient-dried, 3D-printed nanocellulose membrane constructs.
Additionally, it offers a new understanding of the relationship between the design of the material’s deposition pathways via 3D printing, and the dimensional, textural, and geometric effects in the final constructs. This will reportedly allow the team to develop applications of nanocellulose in architectural products that need to meet specific functional and aesthetic user requirements.
“The yet not fully known properties of novel biobased materials prompt architectural researchers to establish alternative approaches to designing these new products, not only in terms of the functional qualities, but also the acceptance from the users. The aesthetics of biobased materials are an important part of this,” said Zboinska.
“If we are to propose these biobased materials to society and people, we need to work with the design as well. This becomes a very strong element for the acceptance of these materials. If people do not accept them, we will not reach the goals of a circular economy and sustainable built environment.”
Researchers involved in the study include Zboinska, Sanna Sämfors and Paul Gatenholm. The work was supported by Adlerbertska Research Foundation and Chalmers University of Technology’s Area of Advance Materials Science.