Environment

Reversible adhesive could boost recycling of electronics

According to the United Nations, 20 to 50 million metric tons (22 to 55 US tons) of e-waste are discarded annually
According to the United Nations, 20 to 50 million metric tons (22 to 55 US tons) of e-waste are discarded annually
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According to the United Nations, 20 to 50 million metric tons (22 to 55 US tons) of e-waste are discarded annually
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According to the United Nations, 20 to 50 million metric tons (22 to 55 US tons) of e-waste are discarded annually

Electronic waste is a growing problem, and if we're ever going to get on top of it, then we need to be able to recycle electronic devices as thoroughly as possible. Thanks to a new temperature-sensitive adhesive, doing so could soon be easier than ever.

The various components of gadgets such as smartphones are often bonded to one another with adhesive, as opposed to being screwed or riveted. This approach keeps the weight of the device down, plus the adhesive may also sometimes serve extra purposes such as insulation or damping.

Unfortunately, though, disassembling those devices may be difficult. De-bonding the components can take a lot of time and energy, and sometimes involves the use of harsh chemicals. Additionally, the parts can be damaged in the process of pulling them apart.

Led by Prof. Christopher Barner-Kowollik, scientists at Germany's Karlsruhe Institute of Technology (KIT) instead looked to an adhesive that they originally developed for use in dentistry.

Made up of long-chain polymer molecules with predetermined breaking points, it remains stable and bonded at room temperature, but disintegrates at temperatures that are significantly warmer yet still not impractically hot. And while the exact "target" temperature can be tweaked according to the intended use of the adhesive, Barner-Kowollik tells us that the effect can be achieved at temps as low as 60 ºC (140 ºF).

This means that electronic devices utilizing the adhesive would presumably still hold together in hot weather, yet wouldn't require too much energy to be heated sufficiently for recycling. And as an added bonus, the adhesive indicates that it's reached the disintegration point by turning pink.

KIT has patented the technology, and is now working with industrial partners to commercialize it.

Source: Karlsruhe Institute of Technology

5 comments
yawood
OK, it won't fall apart on a hot day but what about the heat generated inside the electronic device? Sometimes they can get pretty hot. It will need to be tweaked a fair way.
Mr T
Interesting material, a lot of makers would like to get their hands on this glue as well.
MerlinGuy
Interesting idea that misses the point completely. The major phone maker don't want their products to be easily recycled because that means they can be easily repaired. More repaired, less sold. Wake up.
aki009
If this ever becomes popular, the easiest way to disassemble a cell phone will be to "forget" it on the dashboard of a car in the summer...
Douglas Bennett Rogers
I have a working 286 computer and 3 VCRs, not to mention lots of Generac parts!