A team of chemists at McMaster has discovered an innovative way to break down and dissolve the rubber used in automobile tires, a process which could lead to new recycling methods that have so far proven to be expensive, difficult and largely inefficient.
The method, outlined in the journal Green Chemistry, addresses the enormous environmental burden posed by tires, approximately 3 billion of which were manufactured and purchased worldwide in 2019.
“The chemistry of the tire is very complex and does not lend itself to degradation – for good reason,” says Michael Brook, a professor in the Department of Chemistry & Chemical Biology at McMaster and lead author of the study. “The properties that make tires so durable and stable on the road also make them exceptionally difficult to break down and recycle.”
In the paper, researchers describe a process to efficiently break down the polymeric oils by breaking the sulfur-to-sulfur bond. Brook likens the structure to a piece of fishnet.
“We have found a way to cut all the horizontal lines so instead of having a net, you now have a large number of ropes, which can be isolated and reprocessed much more easily,” he says.
The new method could help to eliminate and prevent the major environmental concerns and dangers posed by stockpiled tires.
While promising, researchers caution that the new method has some limitations because it is expensive for industrial applications.
