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University of Sussex researchers have developed an adhesive that releases in the presence of a magnetic field.
In a new research paper, published by the European Polymer Journal, [Dr. Barnaby Greenland, Lecturer in Medicinal Chemistry, working in conjunction with Stanelco RF Technologies Ltd and Prof Wayne Hayes at the University of Reading] describe a new type of adhesive which contains tiny particles of metal. When passed through an alternating electromagnetic field, the glue melts and products simply fall apart.
The adhesive works with plastic, wood, glass and metal and in terms of strength, is comparable to those currently used in industry.
Dr. Greenland said: "In as little as 30 seconds, we can unstick items using a relatively weak magnetic field.
Relatively little residue remains making recycling easier and the magnetic field levels required are low and safe to be around.
In principle, the formula could be applied to any thermal adhesive making it an innovation which could be incorporated into industry relatively easily.
Dr. Greenland said: "In essence, we could have a big conveyor belt of products going through a magnetic field where they enter fully assembled, and come out the other end completely dismantled.
This technique eliminates the need for harsh chemicals that are generally required to disassemble adhesives currently.
Journal Reference
Sara Salimi et al. Composite polyurethane adhesives that debond-on-demand by hysteresis heating in an oscillating magnetic field[$], European Polymer Journal (2019). DOI: 10.1016/j.eurpolymj.2019.109264
(Score: 0) by Anonymous Coward on Tuesday November 05 2019, @10:46PM
This does not seem to be for hot melt glue common use cases. And some (all?) of those glues already detach if you apply ethanol (maybe also isopropyl alcohol, never tried that one), a tiny drop is enough and there seems to be no real chemical reaction (capillarity based?). Other sticky things disolve in alcohols in a reusable way, like shellac. Or weaken and fall apart with water, like many white glues (PVA, and now you know why basic wood working glues are rated for interior use only).
As for the uses that this glue would replace... maybe those things could use screws. Make them pretty, or placed in such a way that one screw holds other parts that slot into others, puzzle style or as the central stone of an arch that holds everything, eliminating any use of glue (or a tiny drop of locking one). Things that fall apart quick are far from "green solutions". Items would need a label that says "do not place near (electro)magnetic fields, like radios or modern induction kitchens". "Demagnetized card" problem becomes "many things disassemble at random" problem. Great. Not.
But I guess the point is not making things really greener (easier to fix, recyclable but also longer lasting, etc), but saying they are green while the resource consumption grows.