New material for printed circuit boards is set to revolutionise their sustainability
No electronic device works without a circuit board. The problem is that they are difficult to recycle. A new material is now set to improve this.
Researchers at the University of Washington have developed a new printed circuit board (PCB). It is just as powerful as today's printed circuit boards and can be recycled with minimal material loss.
Computer chips, transistors and other components are located on PCBs. Today, they usually consist of fine layers of glass fibre coated with plastic and laminated with copper. This coating makes recycling more difficult because it is difficult to separate from the glass fibres.
With vitrimers to success
The new material used by the researchers is a vitrimer. This substance belongs to the class of polymers developed in 2015. The plastic turns into a kind of jelly when it comes into contact with an organic solvent at a relatively low boiling point. This causes the plastic to swell without damaging the glass panes and electronic components. The material can then be detached from the solid components of the circuit board, allowing the components to be reused. What's more, the vitrimer material itself is also recyclable. The researchers have used it several times to produce new, high-quality printed circuit boards.
Little material is lost in the process. 98 per cent of the vitrimer and 91 per cent of the solvent could be recovered. As much as 100 per cent of the glass fibres contained could be reused. Damaged PCBs with cracks or bends can even be repaired thanks to the vitrimer. According to co-author of the study Vikram Iyer, PCBs make up a large proportion of electronic waste. The new process could therefore avoid a lot of scrap.
Less changes required in the manufacturing process
The vPCB (short for: vitrimer Printed Circuit Board) boards are manufactured in a similar way to conventional PCBs: Usually, semi-cured PCB layers are stored in cool, dry rooms where they have a limited shelf life. They are then laminated in a heat press. As vitrimers form new compounds under certain conditions, the vPCB layers are laminated fully cured. Only minor adjustments would therefore be required in the production of the new printed circuit boards.
In tests, the researchers also found that the material has similar properties to FR4 in terms of strength and electrical properties. This is the most commonly used PCB material. According to initial tests, the production of the new printed circuit boards is expected to produce 48 per cent fewer greenhouse gases and 81 per cent fewer carcinogenic emissions.
Despite the positive properties of the new material, the researchers point out that incentives for recycling are needed. Otherwise, even the most sustainable material won't help. <p
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