OCSiAl test finds no free-standing nanotubes from tire tread wear

Luxembourg – A recent tire wear simulation test commissioned by OCSiAl, has found no free-standing carbon nanotubes in the analysis of airborne particles.

Performed by Akron Rubber Development Laboratory (ARDL) in Cleveland, Ohio, the test introduced OCSiAl’s Tuball nanotubes into tire tread to check the probability of nanoparticles exposure during wear.

Then, an independent laboratory captured any possible aerosol released and applied a specific quantification method relying on Raman spectroscopy for the detection of airborne particles, OCSiAl said in a recent statement.

“Only rubber particles with nanotubes embedded into the matrix were discovered,” said Gunther Van Kerckhove, health & safety lead manager at OCSiAl.

The absence of aerosolised nanotubes, the company said, is expected to promote the "mass use" of single wall carbon nanotubes in the tire industry.

The results tie in with a previous test carried out by European research and technology organisation Vito in 2017.

The Taber abrader tests on single wall carbon nanotube-enhanced epoxy, polyethylene, and elastomer samples showed “no free-standing or protruding nanotubes”, OCSiAl said.

According to the Luxembourg manufacturer, the reason lies in single wall carbon nanotubes’ bonding strength and their unique morphology: ultra-flexible with a 3000:1 length-to-diameter ratio.

“Exposure monitoring studies with material samples are not sufficient for the tire industry,” explained Jean-Nicolas Helt, development and support leader for elastomers at OCSiAl.

“We wanted to check the exposure of a real tire with nanotubes during wear similar road conditions,” he added.

With this result, Helt went on to say, the next step will be to verify that there is no exposure during recycling of the end-of-life tires either.

Single wall carbon nanotubes, also known as graphene nanotubes, are currently offered as alternative rubber reinforcement compared to standard tire additives, such as silica and carbon black.

OCSiAl said it took a lead in initiating the test to address the environmental concerns of the tire industry.