Scientists have developed a new type of rubber that could be used to make tires that never go flat.
Vulcanized rubber is durable and elastic, but it if gets a torn, breaking its chemical bonds, it can’t be repaired with anything other than a patch, which reduces its strength. Tire companies have tried to overcome this drawback by developing tires with built-in foam or gel sealing systems, but they only fill in the holes and don’t reconstitute the rubber itself.
However, in a report published in the American Chemical Society’s Applied Materials and Interfaces journal, a team of German chemists describe how they were able to treat a commonly used tire rubber with a carbon and nitrogen additive that resulted in giving it superior mechanical properties -- including tensile strength and ductility – to vulcanized rubber without using any vulcanization, while along with the ability to heal itself.
The study found that the material can repair itself at room temperature, and after eight days it will withstand over 750 pounds per square inch of pressure, far more than required by an automotive tire. Heating the material to 212 degrees F shortly after a tear accelerated the process, but was not necessary to make it work.
The researchers say that silica and carbon black additives can make the material even stronger, and while it’s not yet ready for commercialization, even more promising for automotive tire use.