What if we could perform an intricate study of the make-up of rubber vehicle tyres in order to engineer the tyre manufacturing process to produce tyres with superior performance? This kind of detailed study has not been possible … until now
Sumitomo Rubber industries, in collaboration with Ibaraki University, has discovered a technique to study individual materials within tyre rubber, utilising a new particle beam microscope to observe, for the first time ever, the sulphur cross-link density.
This ground-breaking technique makes it possible to evaluate the actual rubber that is used in mass-produced tyres (rather than processed test samples), creating enormous potential for the acceleration of future applications in materials development.
The rubber used in vehicle tyres is made up of dozens of different materials, including polymers, for example, natural and synthetic rubber, as well as reinforcing agents like carbon and silica. These materials form complex, hierarchical structures within the rubber, and so, in order to improve overall tyre performance, it is necessary to gain a clearer understanding of these hierarchical structures by observing them individually.
In particular, the structures formed by sulphur cross-links, which give rubber its elasticity, have long been thought to be closely related to rubber’s strength and the changes in its properties over time, for example, its degradation. However, until now, the details of these structures within rubber have remained a mystery.
CEO of Sumitomo Rubber, Satoru Yamamoto, says, “Through this joint research undertaken with Ibaraki University, we have already succeeded in observing the coarse and fine areas (or density) of sulphur cross-links within rubber, in vivid detail, for the first time ever.”
While conventional observation techniques only provide image data that shows an inextricable mixture of sulphur and other reinforcing agents, this new technique generates clear images in which specific compound components, such as silica cross-links, or other reinforcing agents, are each assigned specific colours.
This image data can be used to come up with internal structures for tyres that will provide superior performance in terms of fuel efficiency, wear resistance, and more. Thus, this new breakthrough creates enormous potential for the material development process.