After the cut ot the chemically modified bromobutyl rubber the two ends are put together and heal by itself at room temperature, as testing shows in a video from ACS Headline Science on youtube. (Source: ACS Chemistry for Life)
The research study was published 2 Sept. in the American Chemical Society journal ACS Applied Materials and Interfaces (ACS Appl. Mater. Interfaces, 2015, 7 (37), pp 20623–20630, http://pubs.acs.org/doi/pdf/10.1021/acsami.5b05041, DOI: 10.1021/acsami.5b05041) by the Leibniz-Institut für Polymerforschung Dresden and Technische Universität Dresden, both in Germany, and Tampere University of Technology, Finland.
The researchers found, that transformation of the bromine functionalities of BIIR into ionic imidazolium bromide groups results in the formation of reversible ionic associates that exhibit physical cross-linking ability. 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.
Other mechanical properties, such as the elastic modulus, tensile strength, ductility, and hysteresis loss, were found to be superior to those of conventionally sulfur-cured BIIR. This simple and easy approach to preparing a commercial rubber with self-healing properties offers unique development opportunities in the field of highly engineered materials, such as tires, for which safety, performance, and longer fatigue life are crucial factors.
Testing showed that a cut in the material healed at room temperature, a property that could allow a tire to mend itself while parked. And after 8 days, the rubber could withstand a stress of 754 pounds per square inch. Heating it to 212 degrees Fahrenheit for the first 10 minutes accelerated the repair process. The researchers say their product could be further strengthened by adding reinforcing agents such as silica or carbon black.
Watch a video from ACS Headline Science on youtube to see the rubber heal by itself – please click here:
(dw)
