The study focused on disposable nappies, of which 3.5 million tonnes end up in landfill every year. The superabsorbent properties of nappies come from SAPs: a matrix of polymers which expand when damp. In nappies, the material is based on polyacrylic acid.
There are two broad types of recycling: mechanical recycling and chemical recycling. Mechanical recycling – by far the most common – involves separating plastics by type, shredding them, melting them, and forming fresh feedstock. Although this feedstock is still useful, it is lower quality than raw plastic feedstock because it contains plastic manufactured by various companies containing all sorts of polymers.
“There’s just so many problems, everything usually gets down-cycled and ends up as carpet fibres or park benches,” said Professor Anne McNeil, a polymers expert and co-author of the Nature Communications paper. “Chemical recycling is this idea of using chemistry and chemical transformations to...