DRESDEN, Germany (Sept. 29, 2015) — Unvulcanized, tire-grade bromobutyl rubber can be made to heal cuts or tears through ionic modification, according to a group of German and Finnish researchers.
The research study was published Sept. 2 in the American Chemical Society journal ACS Applied Materials and Interfaces.
“Chemical cross-linking of rubbers by sulfur vulcanization is the only method by which modern automobile tires are manufactured,” according to the abstract of the paper titled Ionic Modification Turns Commercial Rubber into a Self-Healing Material.
Vulcanization substantially reduces rubber's viscous properties, the abstract said, but taking commercially available bromobutyl and transforming its bromine functionalities into ionic imidazolium bromide groups creates cross-linking abilities without vulcanization, it said.
“The reversibility of the ionic association facilitates the healing processes by temperature- or stress-induced rearrangements, thereby enabling a fully cut sample to retain its original properties after application of the self-healing process,” the abstract said.