Researchers from the University of Liverpool have developed a new sulfur polymer that provides an environmentally friendly alternative to traditional petrochemical based plastics.
University of Liverpool chemist and Royal Society Research Fellow, Dr Tom Hasell and his team, have published two papers which demonstrate practical and exciting developments for sulfur polymer technologies and application.
Increasing Strength of Sulfur Polymers
Sulfur is a waste product from many industrial processes and in recent years a growing number of materials scientists have become interested in using it as an environmentally alternative to manufacture plastics. As well as being in plentiful supply, sulfur also has the added advantage of leading to more easily recyclable polymers.
In the first paper, Dr Hasell has made discoveries which addresses the weakness of sulfur polymers, a factor that has limited its application. Led by PhD student Peiyao Yan, the paper demonstrates that adding urethane bonds increases the strength of sulfur polymers by up to 135 times. The way this bonding is introduced means that its amount can be controlled, and in turn controls the physical properties of the polymers.
The strengthened sulfur polymers were found to have shape-memory effects – they can be set in one shape, before being temporarily deformed into another. When heated a little, they ‘remember’ the previous shape and go back to it. The setting process and temporary deformation can be repeated multiple times.
Easy-to-recycle Sulfur Bonds with Various Applications
The sulfur bonds of the polymers are easy to recycle and opens potential applications in areas such as soft robotics, medicine, and self-repairing objects.
In the second paper, Dr Hasell’s group teamed up with researchers at Flinders University in Australia to show that sulfur polymers can form rubber like materials that can be easily self-repaired to their original strength, just by applying an amine catalyst.
The new kind of rubber and catalyst can be used with low energy consumption to make flexible, repairable, sustainable objects – providing a very real and useful application for these new sulfur polymers.
Polymers made from waste sulfur are a viable replacement material for some traditional petrochemical based plastics. The polymers are easily recycled and has new properties for materials chemists to explore.
Source: University of Liverpool