IEC Panel: Material innovations driving greater sustainability

CLEVELAND—Polymer Sciences resonated with Lance Miller. As a student at the University of Akron, he was drawn to the challenges they offered.

It was the place his scientific heart just needed to be. And for more than two decades he's found his place in the rubber industry, first at Gates Corp., then Veyance Technologies and now Continental ContiTech where he is an R&D Fellow.

Still, through it all, there was always something that just never felt quite right.

"It always bothered me a little bit inside that what we were doing was so petroleum-based and we were damaging the world for products that we thought were enabling a better quality of life," he said of the polymer sciences and their related industries.

But his heart finds hope in the new ideas—big ideas—that are driving the rubber industry toward more sustainable materials.

"To see these sustainability initiatives coming out of so many different companies and universities, consortia—it is a wonderful time to be science," Miller said.

During a panel discussion that helped to kick off the first day of the ACS Rubber Division's International Elastomer Conference on the expo floor, Miller was joined by others across the industry who helped to detail some of the developments that are driving change.

Developments of the recycled kind, for instance.

One of the most promising feedstocks for recycled and recovered materials is end-of-life tires. The tire pyrolysis process yields incredibly valuable materials such as recovered carbon blacks and process oils that can help ensure greater circularity for the industry overall.

"I think it is important to think about the pyrolysis process, which gets you the recovered carbon black, also produces tire pyrolysis oil, which has a lot of value downstream for a lot of sustainable carbon black and sustainable process oil," said Ronald Shaffer, senior manager of materials and sustainability at Bridgestone Americas Inc. "Try to think of this as an ecosystem.

"We need some of the rCB materials, but we also need some of the other products that process produces in order to build up that ecosystem so that our compounders have a sort of portfolio or menu of options at our disposal."

One of the tricky things about recovered carbon blacks, though, is that it can be tough to ensure the consistency of the product, particularly when you consider the diversity of the waste tire feedstock itself.

"You start with end-of-life tires, so what you get out the other end is a mixture of different grades of carbon black," Shaffer said, "so that has to be something that the compounders have to account for. That is part of the strategy."

Another part of the strategy for the industry involves virgin carbon black production that relies on more sustainable manufacturing methods. Take methane pyrolysis, which uses a plasma arc reactor to form the CB during methane decomposition.

Because the process produces only sustainable hydrogen as a byproduct, it offers great sustainability benefits.

And the way Nihat Isitman—a polymer materials scientist at Apple Inc.—sees it, the methane pyrolysis method could be one of the most promising on a commercial scale.

"From a commercial and supply chain standpoint, I think the runner up is going to be a methane pyrolysis carbon black," Isitman said. "… As soon as a similar solution is found, it will be easier to get into reinforcement blacks. That solution, from a carbon footprint standpoint and a supply chain standpoint, that is going to be the most easy to scale."

For Bridgestone, one of the most prominent renewable materials is guayule. Over more than a decade the tire maker has invested more than $100 million in the cultivation, study and scale-up of the alternative natural rubber.

And that investment has proven itself, Shaffer said, pointing to the ways in which Bridgestone has incorporated the guayule in its products—specifically a 75-percent sustainable materials demonstration tire and the sidewall of the Firestone Firehawk racing tires.

But Shaffer was quick to note that the Firestone Firehawk tires prove out the value of another sustainable rubber concept that shouldn't be lost in the conversation—more sustainable SR.

"There is certainly a role for sustainable synthetic rubber as well where you are producing the rubber from a sustainable monomer feedstock," Shaffer said. "A good example of that is … where Firestone Indy Car racing tires used a sustainable synthetic rubber in it. And that is going to continue to be a major part of the tire and rubber industry."

When it comes to bio-sourced materials, though, one of the most encouraging are those silicas that can be derived from renewable and bio-based sources, such as rice husk.

"It took me a while to realize that material was out there, but when I did, I was quite pleased," Miller said. "It did a very good job—in fact, it did a wonderful job replacing some of the regular products. There can be a little mismatch between the surface area and the amount of reinforcement given in the rice husk version, but you can make the adjustments and make it work. It was great to see that that was out there."

Moving forward one of the key points of focus, Miller said, should be working to ensure more domestic supplies of the material. Already, he said, PPG has brought this product to the market in the Americas, but ensuring a greater supply would be ideal, in part because local supplies help to reduce overall carbon footprints.

"It would be nice to have some domestic supply of that here in the Americas because typically the supply of that comes from other areas of the world—Asia primarily," Miller said. "But they are good materials, I am not going to turn it down."

Another material that Miller won't be quick to turn down? Plant-based oils.

"I would like it to be that we could use corn oil that is popular to be able to use it less in high-fructose corn syrup world and use it more in softening rubber components. I think that would be a wonderful thing not only for human diets, but everyone's wellbeing.

Sustainability can be a tricky prospect. Because there is so much to consider beyond what makes up a product or how a material is derived.

It was a point that Gabriela Quevedo-Silvetti, global marketing and sustainability manager for TotalEnergies S.E., emphasized.

Any moves toward more sustainable materials, she said, has to "avoid deforestation, avoid an impact on biodiversity and avoid, also, an impact on food. It has to be safe at full upscale."

Miller agreed.

In the end, he said, the movement toward more sustainable materials—as well as sustainable products and operations—is about doing what's right overall. It's about protecting the planet and its people as best as possible, even if it means making some missteps along the way.

"I want to do the right thing," Miller said. "Sometimes, what seems to be the right thing today is found tomorrow to not be. … Do I think we will have these solutions tomorrow? (No.) Do I think we will make some mistakes along the way? Sure. But this has got to be the right way to go, and I applaud all the companies that have 2050 goals to get to that route."

In an industry as innovative as polymers, he's certain they'll achieve it.