Scientists at the University of Liverpool have discovered a new process to make polymers out of sulfur which could provide a way of making plastics less harmful to the environment.
Sulfur, whilst being identified as a possible alternative to carbon in the manufacture of polymers, cannot form a stable polymer on its own.
However, as revealed in a process called ‘inverse vulcanisation’ it must be reacted with organic crosslinker molecules to make it stable.
This process can require high temperatures, long reaction times, and produce harmful by-products.
In light of this, researchers from the University of Liverpool’s Stephenson Institute of Renewable Energy, working in the field of materials chemistry, have made a potentially game changing discovery.
In a study published in Nature Communications, they report the discovery of a new catalytic process for inverse vulcanisation that reduces the required reaction times and temperatures, whilst preventing the production of harmful by-products.
It also increases the reaction yields, improves the physical properties of the polymers, and allows a wider range of crosslinkers to be used.
“Making polymers (plastics) out of sulfur is a potential game changer. To be able to produce useful plastic materials from sulfur, a by-product of petroleum, could reduce society’s reliance on polymers made from petroleum itself. In addition, these sulfur polymers may be easier to recycle, which opens up exciting possibilities for reducing current use of plastics,” said Dr Tom Hasell, Royal Society University Research Fellow at the University, whose group conducted the research.
"In addition to this, is the scope for unique new polymers with unprecedented properties. The properties of sulfur are very different to carbon, and this has already opened up a world of possible applications for sulfur polymers including thermal imaging lenses, batteries, water purification and human health."
He added: “We made the key discovery when we decided to look to the acceleration of traditional rubber vulcanisation for inspiration. This research now marks a significant step forward in the development of inverse vulcanised polymers. It makes inverse vulcanisation more widely applicable, efficient, eco-friendly and productive than the previous routes, not only broadening the fundamental chemistry itself, but also opening the door for the industrialisation and broad application of these fascinating new materials in many areas of chemical and material science.”
The research was led by University of Liverpool and involved collaboration with the University of Lancaster.