In our modern world, we use electronic devices every day, but what happens to them when they are not usable anymore?
Unfortunately, they often end up as electronic waste or e-waste, which can be dangerous to both our health and the environment.
Traditional ways of recycling e-waste, like burning it (pyrometallurgy), can create even more problems. Printed Electronics (PE), which are electronic devices printed mainly on fossil-based materials like plastic, have their unique challenges when it comes to recycling.
To tackle this issue, researchers are exploring more sustainable methods like hydrometallurgy, which is kinder to the planet and can recover more valuable materials. However, even this method has its downsides since it still relies on harmful chemicals.
There are new, high-tech ways to recycle metals from electronics that use heat, but these also face obstacles when it comes to PE.
Although many studies have been conducted on recyclable and biodegradable printed electronics, few have successfully demonstrated their production, usage, and end-of-life disposal, and even fewer have addressed the scalability of these designs, which is a key factor for practical implementation. Indeed, recycling PE can be challenging due to the deterioration of materials after each cycle, making it difficult to reuse them.
So, what would be a safe solution for e-waste recycling?
The SaP project has come up with an innovative solution to tackle this problem!
First, let’s understand each part of a PE device.
A generic printed electronic device consists basically of four main components that work together to provide its functionality.
It is the base layer of the device and provides the necessary mechanical support. It is typically made of a flexible or rigid material, such as PET (polyethylene terephthalate) or FR4 (a type of fiberglass epoxy), respectively. The substrate material plays an important role in the overall device performance, as it needs to be able to withstand the processing conditions and provide the necessary mechanical stability for the device.
They are applied to the substrate to form the conductive traces and components of the device. These inks are made of various materials, such as silver, gold, or carbon, and can be printed using various printing techniques. The choice of ink material and printing technique depends on the specific device requirements, such as conductivity, resolution, and cost.
It is used to separate the conductive traces and prevent electrical shorts. It is typically made of a non-conductive material, such as a polymer or ceramic, and can be printed using various techniques, such as inkjet or spray coating.
It is used to bond the device to other components or a final product. It is typically made of a pressure-sensitive adhesive, such as acrylic or rubber-based adhesives, or a thermosetting adhesive, such as epoxy or silicone. The choice of adhesive material depends on the specific application requirements, such as adhesion strength, environmental resistance, and temperature resistance.
Recycling devices like this takes not only a solution to dissemble their discrete components but also to recover and reuse them. The development of sustainable and eco-friendly materials and processes for these components is crucial for the advancement of green printed electronics.
Now, coming back to the SaP solution…
THE SaP SOLUTION
The SaP consortium is developing a more sustainable and holistic approach to product design based on lifecycle analysis and recycling methods for e-waste, including nano-waste. SaP aims to reduce the use of chemical leaching agents and use greener alternatives, ultimately improving the overall sustainability of PE.
The solution focuses on the entire path of production and scalability, aiming to improve the current state-of-the-art of recyclable and biodegradable PE to create circular avenues for PE and reduce 95-98% of the carbon footprint of the technology. The goal is to extract and recycle over 90% of the metal used in PE, making it a more sustainable option for the environment.
Furthermore, SaP aims to tackle one of the major challenges in PE: the separation of discrete components. These components, such as chip capacitors and resistors, are bonded onto the PE circuits with strong adhesives that are not easily disassembled. Besides, these components represent a considerable material cost and value in PE products. To address this SaP will develop a de-mounting process to break the bonds between the PE parts and separate them easily. These parts can then be reused in other devices resulting in energy and material conservation, and economic gains when upscaled.
To wrap up:
Ultimately, the SaP project is an excellent example of how innovation and sustainability can work together to build a better future for us all.
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6 T. Kasuga et al., ACS Appl. Mater. Interfaces, vol. 11, no. 46, pp. 43488–43493, 2019
7 P. Usapein et al., App. Envi. Res., 38 (1), 11-17, 2016. & https://ecoinvent.org/the-ecoinvent-database/
8 Sustain-a-Print Grant Agreement 101070556 – part B, pp. 103-104, 2022.
Funded by the European Union under the GA no 101070556. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or RIA. Neither the European Union nor the granting authority can be held responsible for them.