Researchers at the University of Surrey in England have developed a polymer that turns into a gas when heated to 90°C and reforms into the original waterproof material when cooled.
The research, published in the scientific journal Macromolecules, describes a polymer with properties similar to PE. It is soft, insoluble and hydrophobic, but differs from conventional plastics in the way it responds to heat.
At 90°C, the polymer undergoes depolymerisation, breaking down into its individual building blocks, known as monomers. While many depolymerisation processes produce monomers in liquid form, the University of Surrey material produces a gas. As the material cools, it reforms into the original polymer.
Potential uses
The researchers demonstrated several potential uses for the material as part of the study.
In one demonstration, they produced a waterproof polymer coating by allowing the polymer vapour to condense onto a surface. The coating could then be removed by reheating it, causing the polymer to evaporate.
The team also demonstrated how the approach could be used to purify the polymer. A contaminated sample was subjected to sublimation, allowing the polymer to be separated from a model additive before reforming as a clean solid.
The researchers said the work was intended as a proof of concept for a new class of circular materials. The approach could eventually be used for applying and removing waterproof coatings, particularly where liquid coatings have difficulty covering complex surfaces.
‘Behaves very differently’
Dr Peter Roth, school postgraduate research director and senior lecturer in Applied Organic/Polymer Chemistry at the University of Surrey, said: “Most plastics are designed to be stable, which is exactly what makes them difficult to recycle or remove.
“We’ve shown that it’s possible to create a material that behaves very differently, one that can transform into a vapour at relatively low temperatures before naturally rebuilding itself into the same polymer.
“This isn’t a replacement for conventional plastics, and it’s certainly not a solution to the global plastics waste problem. But it does introduce a new concept that could inspire an entirely new generation of circular materials.”
