Sumitomo Rubber Industries, Ltd. (CEO: Satoru Yamamoto) was pleased to announce that, through joint research undertaken with Ibaraki University, SRI has established a new technique for selectively observing any of the various materials contained within tyre rubber.
Utilising a new particle beam microscope recently developed by Ibaraki University, this groundbreaking 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 future applications in materials development. Using this technique, the company said they have already succeeded in observing both coarse areas and fine areas (i.e. density) of sulfur cross-links*1within rubber in vivid detail for the first time*2ever.
The rubber used in automobile tyres is made up of dozens of different types of materials, including polymers such as natural and synthetic rubber, reinforcing agents such as carbon and silica and so forth. These various materials form complex, hierarchical structures within the rubber. And so, in order to improve overall tyre performance, it is thus necessary to gain a clearer understanding of these hierarchical structures by observing the structures of each of the materials that make up tyre rubber in isolation. In particular, the structures formed by sulfur cross-links, which give rubber its elasticity, have long been thought to be closely related to rubber strength and changes in rubber properties over time, (such as degradation), as well. However, up until now, the details of these structures within rubber have remained shrouded in mystery.
While conventional observation techniques only provide image data that shows an inextricable mixture of sulfur 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 colors. By allowing evaluation of the very structures of tyres themselves, 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 so forth. Thus, this new breakthrough creates enormous potential for the acceleration of the material development process.