Researchers at The University of Manchester have demonstrated that when a small amount of graphene is added to thin rubber films, they become significantly stretchier and stronger.
Graphene - the wonder material - is the strongest and thinnest substance in the world. Dr Maria Iliut and Dr Aravind Vijayaraghavan observed that when this material is added to rubber films, the elasticity and strength of these films increased by as much as 50%. Ubiquitous in everyday life, thin rubber films are utilized in many different applications, ranging from condoms to gloves.
The results of the study have been reported in Carbon.
During the experiments, the team examined two types of rubbery materials – a synthetic rubber known as polyurethane and a natural rubber made of polyisoprene material. Graphene of different sizes, kinds, and amounts was added to both types of rubber. In the majority of experiments, it was seen that the resulting composite material can be significantly extended with more force before it breaks off. Adding a very small amount of graphene - one tenth of one percent - was sufficient to make the rubber 50% stronger.
Dr Vijayaraghavan, who heads the Nano-functional Materials Group at The University of Manchester, explains “A composite is a material which contains two parts, a matrix which is soft and light and a filler which is strong. Taken together, you get something which is both light and strong. This is the principle behind carbon fibre composites used in sports cars, or Kevlar composites used in body armour. In this case, we have made a composite of rubber, which is soft and stretchy but fragile, with graphene and the resulting material is both stronger and stretcher”
We use a form of graphene called graphene oxide, which unlike graphene is stable as a dispersion in water. The rubber materials are also in a form that is stable in water, allowing us to combine them before forming thin films with a process called dip molding. The important thing here is that because these films are so thin, we need a strengthening filler which is also very thin. Fortunately, graphene is both the thinnest and strongest material we know of.
Dr Maria Iliut, Research Associate, University of Manchester
The study was initiated from a call by the Bill & Melinda Gates Foundation to devise a preferable condom. This composite material holds immense implications in everyday life, according to Dr Vijayaraghavan.
Our thinking was that if we could make the rubber used in condoms stronger and stretchier, then you could use that to make even thinner condoms which would feel better without breaking. Similar arguments can be made for using this material to make better gloves, sportswear, medical devices and so on. We are seeing considerable industrial interest in this area and we hope more companies will want to get involved in the commercial opportunities this research could create.
Dr Aravind Vijayaraghavan, Head of the Nano-Functional Materials Group, University of Manchester