Collaborative research project leads to development of crack-resistant material by Yokohama

Yokohama, in collaboration with Shinshu University, has developed a rubber material with crack resistance made from nanoparticle-based tough polymers that do not use any additives, such as organic solvents and reinforcing agents.

The development is the result of a collaborative effort between the tire maker and a research group led by associate professor Daisuke Suzuki of Shinshu University’s Graduate School of Textile Science and Technology and RISM (Research Initiative for Supra-Materials). Further research based on the knowledge gained during the project is expected to lead to the development of safer and more durable tires and rubber products.

The developed rubber material can be easily recycled without deterioration and could play a key role in the realization of a circular economy.

The research project used nanoparticle-based polymers (hereafter, nanoparticles) synthesized via mini-emulsion polymerization (a well-known polymerization method) and a nanoparticle dispersed aqueous solution to create a nanoparticle film (rubber material) formed by evaporating the water from the dispersed aqueous solution. Inserting rotaxane molecules (also known as supramolecular compounds) into these nanoparticles as a crosslinking agent enhances resistance to crack propagation without using other additives, such as reinforcing agents. This nanoparticle film also contributes to the rubber material’s high elasticity.

Nanoparticle films composed of only nanoparticles can be decomposed simply by immersing them in a water-ethanol solution. Since this water-ethanol solution can be returned to the dispersed aqueous solution that is composed of nanoparticles and water simply by evaporating the highly volatile ethanol, the nanoparticle film can be easily regenerated without any deterioration.