The world’s demand for natural rubber is increasing, and many are concerned that the rubber tree (a.k.a. the Hevea tree) won’t be able to keep up. It’s only grown in a relatively thin strip around the equator in jungle-like locations that are not fun for workers, and where landowners have more lucrative crop options (some legal, some not so much). On top of that, it takes seven years before you can harvest rubber from a rubber tree.
So a consortium — led by Cooper Tires and which includes Arizona State University — has a $6.9-million grant from the U.S. government to look into the possibility of large-scale growth and production of guayule-based natural rubber.
Arizona State is looking at the entire social and environmental impact of turning desert into guayule farmland.
We could just use more synthetic rubber, sourced from petrochemicals, but that’s not ideal, and natural rubber is a very unique product.
Even with all their laboratories and white coats, tire scientists still prefer to use natural rubber in tires.
“Natural rubber is the closest thing to the perfect elastomer. If I could only use one elastromer in a tire, I would chose natural rubber,” says Cooper Tire research scientist Howard Colvin, from the company’s headquarters in Findlay, Ohio.
Colvin says natural rubber has lots of beneficial properties, but among the most prized is its ability to self-heal.
“When you get a small crack in the rubber compound, the crack stops immediately. In synthetics that is not the case. This is especially important in a sidewall, where you have a lot of flexing going on.”
Natural rubber stays “cooler” than synthetic rubbers.
According to Colvin, the rubber fibres sourced from guayule are remarkably similar to fibres sourced from Hevea, except that guayule, “smells a lot better … fresher … a bit like Pine Sol.”
Guayule can be harvested every 18 months, and harvesting nets useful byproducts, such as resins and biomass that can be processed into fuel.
Many tire makers, including Cooper, are also looking into Russian dandelion-sourced rubber; its main byproduct is sugars.
Colvin’s colleague, Chuck Yurkovich, Cooper’s vice-president of global technology, personally feels that guayule is closer to being a realist rubber resource than Russian dandelion. How close?
“We’re at the point where we are building and testing tires. But a lot also depends on the success of the agronomic part of the equation. Then there would be manufacturing capabilities to be built up. But theoretically you could have a product on the market that uses some guayule rubber in five to 10 years. A lot depends on what happens in the next 12 to 18 months.”