Sumitomo advances understanding of rubber breakdown mechanism

Tokyo – Sumitomo Rubber Industries (SRI) has presented new findings on a study into the mechanism of rubber failure, a key factor that determines the durability of tires, SRI announced 19 March.

 The joint research with prof Gert Heinrich of Dresden University of Technology, Saxony, Germany, was presented at an invited lecture at the American Chemical Society, 6-7 March in Orlando, Florida.

The work, which involved Leibniz Institute of Polymer Research Dresden, focused in on the "cracking phenomenon," in which cracks and fissures that occur in rubber materials progress, according to SRI.

Until now, it explained, “rubber durability has been evaluated using tear tests and other methods, but there were many unknowns about the structural changes at the microscale at the tip of the crack.”

For the latest research programme, simulation technology was used to analyse the forces acting on the tip of a crack in rubber and clarify the factors that determine the development of cracking.

The tip of a crack in rubber undergoes expansion deformation, generating voids which, as they grow and coalesce, worsen the crack. However, it was also revealed that the generation of voids reduces the stress concentrated at the tip of the crack.

“We will continue to conduct research into the force distribution and crack characteristics when changing the void dispersion state,” said SRI, highlighting its goals to enhance the wear resistance and reduce the environmental impact of tires.

“By utilising the data obtained from this joint research… we will promote the development of more highly functional and high-quality tires,” the Japan-based tire manufacturer concluded.