Coca-Cola and several other major companies recently invested millions of dollars to push forward a nascent resin called PEF, and the move raises questions about the composition of the plastics recycling stream in the decades to come.

The $50 million in funding, announced earlier this month, aims to help a Dutch research and technology company called Avantium further develop a process that could open the door to plastic bottles and other products made from 100 percent plant-based materials.

The plastic being researched looks and feels like PET but is actually a material with a different molecular structure. Just like PET, the first ingredient is ethylene glycol, but instead of being combined with a terephthalic acid, it is joined with a furanic, creating polyethylene furanoate, or PEF.

“It’s still a polyester but using this process, the material offers some potential advantages in terms of barrier, thermal and mechanical properties,” said Scott VItters, general manager of the PlantBottle packaging platform at Coca-Cola. Early tests on PEF bottles, Vitters said, have shown they could help beverage makers lengthen shelf life and create lighter weight bottles without compromising strength. “It’s very compelling from both the environmental and economic perspective to our business,” said Vitters.

YXY, the Avantium technology used to make PEF — which is also being backed by DANONE, Swire Pacific and ALPLA — is one avenue Coca-Cola is exploring as it tries to manufacture its PlantBottle packaging entirely from bio-based sources. PlantBottles are currently in wide use in the U.S. and many other markets. They are made of PET plastic, leveraging ethylene glycol derived from plant-based sources, and they can be recycled within the PET stream.

However, ethylene glycol makes up 30 percent of the molecular weight of bottles, and the remaining 70 percent of a PlantBottle continues to be made using petroleum as a source. Coca-Cola has publicly stated it intends to eventually market a PlantBottle made entirely from plants or other renewable sources. PEF could achieve that need because Avantium’s YXY process uses carbohydrates from sugar cane, sugar beet, corn or wheat as feedstock.

And according to Avantium CEO Tom van Aken, the company is researching how it can use “second generation” feedstock materials such as agricultural waste or paper waste.

To be sure, PEF bottles are still just in a testing phase and are years away from actually hitting the marketplace — van Aken said the latest round of investment is being used to finance the first commercial-scale plant for the manufacture of the material, and he noted the facility won’t be fully operational until 2017.

But members of the plastics recycling industry are no doubt taking notice. If Coca-Cola and other companies embrace PEF down the road, what will that mean for processing lines, particularly those with a focus on PET?

Vitters is quick to point out that though Coca-Cola has been encouraged by early PEF tests, the company has no plans to move away from PET any time soon. “We have a recycling business, and we’ve been a leader in advancing recycled content technologies,” Vitters said. “We have a shared interest in ensuring the PET market is protected, given the investments we’ve made.”

Vitters and van Aken said initial recycling tests have focused on whether PEF bottles can be recycled back into new PEF bottles as well as whether recycled PEF can be used in the clothing, carpet and other polyester markets. They said the material has shown it performed well in both those applications.

However, it remains unclear how much PEF content a PET stream could handle. A post last April on a blog called Polymer Innovation stated the current PET stream could be made up of up to 5 percent PEF without contamination. Jeff Gotro, who wrote the blog post and is president of plastics technology firm InnoCentrix, said in an email he got that statistic from an Avantium presentation at the BioPlastics Conference in June 2012.

Avantium’s van Aken would not confirm the 5 percent figure. “Avantium and its partners are carefully reviewing the impact of PEF in the rPET stream,” the executive said when asked how PEF and PET could potentially intermingle. “The company is working with players in the plastics and PET recycling business to evaluate the recycling and sorting of PEF in relation with other recycling streams to determine how PEF may affect other recycling streams and to come to the best end-of-life option.”

Vitters said it’s too early in the research and development process to make any claims about how much PEF a PET stream can handle. And he said his business will incorporate industry organizations into the picture if and when PEF starts to make its way to the market. “On the recycling side, Coke with any new material would follow the existing protocols either from the EU or the United States,” he said. “There’s APR and the Petcore protocol for assessing recycling impact. That’s the kind of work we’ll do as we’re advancing the technology to better understand what the recycling impact might be and ensure it is managed responsibly.”

He also indicated that should PEF be the bio-based solution ushered forward by Coca-Cola and other plastics players, a PEF-only recycling stream may very likely follow. “If the material delivers the kind of properties that seem to be [present], you can imagine the interest that might be there beyond just in the beverage space,” Vitters said. “If those are delivered on clearly, the scale would be there so that, if needed, you could argue for potentially creating a separate stream around this material.”