Reversible adhesive could boost recycling of electronics
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.