Is the biodegradable PCB environmentally friendly enough?

PCB is an integral part of every electronic product. With the increase in the use of electronic gadgets in all aspects of our lives and due to their shortened lifespan, one thing is the increase in the amount of e-waste. With the development of emerging industries such as the Internet of Things and the vigorous development of advanced driver assistance technologies in the automotive sector, this growth will only accelerate.


Why PCB waste is a real problem?

Although PCB designs can be used for many years, the fact is that these small tools that PCB dominate are being replaced at an alarming frequency. Therefore, a key issue that arises is the decomposition problem, which leads to many environmental problems. Especially in developed countries, because a large number of discarded electronic products are transported to landfills, they release toxic substances into the environment, such as:

Mercury-may cause kidney and brain damage.

Cadmium-known to cause cancer.

Lead-known to cause brain damage

Brominated flame retardants (BFR)-known to affect women’s hormonal function.

Beryllium-known to cause cancer

Even if the board is recycled and reused instead of throwing it into a landfill, the recycling process is dangerous and can cause health hazards. Another problem is that as our equipment gets smaller and lighter, it is a difficult task to take them apart to recycle the recyclable parts. Before withdrawing any recyclable materials, all glues and adhesives used need to be manually removed. Therefore, the process is very laborious. Usually, this means shipping PCB boards to less developed countries with lower labor costs. The answer to these questions (electronic equipment piled up in landfills or they are recycled) is obviously biodegradable PCB, which can greatly reduce e-waste.

Replacing current toxic materials with transient metals (such as tungsten or zinc) is a big step in this direction. A team of scientists at the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign has set out to create a fully functional PCB that decomposes when exposed to water. The PCB is made of the following materials:

Commercial off-the-shelf components

Magnesium paste

Tungsten Paste

Sodium Carboxymethyl Cellulose (Na-CMC) Substrate

Polyethylene oxide (PEO) bonding layer

In fact, fully biodegradable PCBs have been developed using biocomposites made of natural cellulose fibers extracted from banana stems and wheat gluten. The biocomposite material does not contain chemical substances. These biodegradable transient PCBs have similar properties to conventional PCBs. Some biodegradable PCBs have also been developed using chicken feathers and glass fibers.

Biopolymers such as carbohydrates and proteins are biodegradable, but the natural resources they require (such as land and water) are becoming scarce. Renewable and sustainable biopolymers can also be obtained from agricultural waste (such as banana fiber), which is extracted from plant stems. These agricultural by-products can be used to develop fully biodegradable composite materials.

Is the environmental protection board reliable?

Usually, the term “environmental protection” reminds people of the image of fragile products, which is not the attribute we want to associate with PCBs. Some of our concerns regarding green PCB boards include:

Mechanical properties-The fact that environmentally friendly boards are made of banana fiber makes us think that boards may be as fragile as leaves. But the fact is that researchers are combining substrate materials to make boards that are comparable in strength to conventional boards.

Thermal performance-PCB needs to be excellent in thermal performance and not easy to catch fire. It is known that biological materials have a lower temperature threshold, so in a sense, this fear is well-founded. However, low temperature solder can help avoid this problem.

Dielectric constant-This is the area where the performance of the biodegradable board is the same as that of the traditional board. The dielectric constants achieved by these plates are well within the required range.

Performance under extreme conditions-If the PCB of the biocomposite material is exposed to high humidity or high temperature, the output deviation will not be observed.

Heat dissipation-biocomposite materials can radiate a lot of heat, which is a required characteristic of PCBs.

As the use of electronic products becomes more and more widespread, electronic waste will continue to grow to an alarming extent. However, the good news is that with the further development of research on environmental protection options, green boards will become a commercial reality, thereby reducing e-waste and e-recycling issues. While we are contending with past e-waste and current electronic equipment, it is time for us to look to the future and ensure the widespread use of biodegradable PCBs.