Printed circuit boards (PCBs) are a major component of the world's fastest growing e-waste. Such items are currently made from non-biodegradable and hard-to-recycle substances, but researchers see great potential in manufacturing them from bio-based components.
What are circuit boards made of?
Most PCBs in use today are designed with functionality and cost in mind, not what happens to the product when it is no longer in use.
According to the list of components of PCB materials, a material called "FR-4", which is a mixture of woven glass fibers, epoxy resin and copper foil, is the most prevalent.
FR-4 begins with a composite of paper and glass fibers, called composite epoxy, which are woven together to form a fabric-like sheet impregnated with epoxy resin. Epoxy is a thermosetting plastic that provides a protective electrical insulation against short circuits.
The entire surface of the FR-4 base layer is coated with a layer of copper. A chemical is used to invisibly paint over the copper to remove the final circuit design. When the whole thing is immersed in a caustic chemical bath, the excess copper areas dissolve away, leaving only metal lines to mark the chemtrail circuit design. Silver ink can also be used to depict circuit boards, although copper is more common.
What's wrong with PCBs?
FR-4 is so popular in PCBs because the material used in it is resistant to moisture, chemicals and heat. However, it contains toxic chemicals within it.
In addition to epoxy resins, other resins can be used to reinforce fiberglass panels. These may be cyanate esters, polyimides, polyesters.
However, regardless of what they are specifically made of, most PCB materials are not safe for human or environmental health. One of the most toxic components of PCBs are halogenated flame retardants, which cause cancer and disrupt neurological function in humans and animals.
Moreover, less than 20% of used PCBs are recycled and the economic incentives are non-existent. Their disposal of used PCBs is costly and inefficient, and they lack well-designed collection systems.
The lack of e-waste management policies means that most circuit boards end up in landfills, where synthetic polymers release toxic compounds.
Advantages of BioBoard?
Biodegradable circuit boards will go a long way in helping to reduce the environmental hazards of e-waste.
Bio-based materials for PCBs address the environmental concerns of existing circuit boards in two ways: they reduce the ecotoxicity of PCBs at the end of their useful life, and they also reduce emissions from the production process.
The researchers say that paper circuit boards emit much less global warming emissions than FR-4, and have much better environmental impact metrics for each of its entire life cycle, except for land use (after all, paper needs forests).
What kind of biomaterials can go into circuit boards?
What materials can be used to make bio-based circular circuit boards?
We should know that a printed circuit board is a relatively simple concept: a board is just an instruction manual or a kind of electronic map. This is for basic prototyping. Engineers can even draw circuits manually with metal ink using simple paper or cardboard.
This is why materials such as paper, linen and bio-based resin matrices in the prototype PCBs were seen as effective alternatives to FR-4, at least in the demonstration program.
They have also been shown to reduce the environmental impact of PCB materials, improve the recycling and reuse of metals and electronic components, minimize the use of toxic flame retardants, and provide pathways to safer end-of-life management.
Theoretical possibilities for PCB materials even include banana and cellulose fibers, although these have not yet been made into functional prototypes.
However, how do you get this low-resource-intensity material to be practically applicable on a commercial scale? This is a great challenge. Paper, for example, is great for prototyping, but not tough enough to be used as a durable PC component, and it is not flame retardant. This is a problem when hand-inked metal circuits are replaced by heat-intensive assembly processes such as soldering.
Hampshire Leads in Biobased PCBs
Hampshire, UK-based Jiva Materials has found a way to commercialize bio-based circuit boards. The company claims to have created the world's first fully recyclable rigid printed circuit board under the brand name Soluboard.
The recyclability of its PCBs comes from its natural fiber composition, replacing the glass fibers and epoxy resins used in traditional circuit board manufacturing.
In Jiva Material's circuit board manufacturing process, the braided fibers are not made from plastic or glass, but from unprocessed natural materials. The braided fiber fabric is then impregnated with water-soluble polymers and halogen-free flame retardants. Natural materials are designed to reduce the overall carbon footprint of the product compared to traditional manufacturing routes. Halogen-free flame retardants are slightly less harmful to the product.
Reducing ecologically harmful materials does more than just reduce the amount of carbon released by PCBs. It also makes it easier to recycle the board and everything printed on it. Once a circuit board reaches the end of its useful life, organic circuit boards can be dissolved in hot water in a controlled environment, leaving only copper, any other valuable metal components and natural fibers - all of which can be reused. Water-soluble circuit boards can reduce the high cost issues that hinder the recycling of today's circuit boards.
Jiva's research into bio-based PCBs is ongoing. The company is working with the University of Southampton to test the properties of other natural fibers, such as jute, flax and hemp, as potential laminating materials.
According to project advisor Stephen Woodhouse, the program is designed to scale up Jiva Materials' products while allowing the company to pursue additional technological innovations by reaching out to university researchers in the materials field.
Chip maker pilots biological motherboards
Jiva Materials' customer, Infineon Technologies, has begun trialing biodegradable Soluboard in consumer applications.Last year, Infineon produced 500 PCBs of three different types using Soluboard material to reveal how semiconductors on bio-based circuit boards can be reused and recycled.
Infineon is a German-based semiconductor specialist founded in 2009 as a subsidiary of Siemens. Tracking Soluboard is part of the company's strategy to reduce the carbon footprint of demo and evaluation boards, which are used to test the functionality of PCB designs.
The company says the drive to reduce carbon emissions from its electronics comes from the European Commission's Green Deal climate neutrality targets, suggesting that there could be a wave of new demand for bio-based PCB innovations from EU electronics manufacturers in the near future.
Microsoft invests in sustainable PCB research
Microsoft is also working on more sustainable PCB substrate materials made with renewable materials.
They are working with a team from the Intelligence Research Group, a collaborative effort at the University of California, Irvine, to research biodegradable and non-toxic PWB materials and develop a framework for best practices in manufacturing sustainable circuit boards.
In 2022, a team from Microsoft published an article in Nature on the possibility of replacing polymers, resins, and other synthetic materials with bio-based alternatives, demonstrating the need for more research into new materials and regulatory policies for e-waste management.
Disappearing electronics
Some researchers dream of an entirely different model of e-resource utilization where fully biodegradable products are the norm.
In this technological vision, all materials used in the manufacture of hardware can be collected and reused at the end of their life cycle in one sector or another: the degradation of paper circuit boards into nutrient-rich agricultural mulch also releases any critical minerals from the boards in the process, preparing them for reuse in electronics and industry.
Researcher Vincent Arroyos and his colleagues have envisioned a life cycle for sustainably degradable circuit boards. "We may be a long way from realizing ephemeral plant-based electronics, but there is already optimism that the use of some bio-based materials in common components could help reduce the environmental harm caused by e-waste."
