DALLAS — Plastics certainly can be recycled, said Adrian Merrington.
Some can be recycled economically. Some can be recycled environmentally. And some can even be recycled very profitably.
But not all, said the senior associate scientist at the Michigan Molecular Institute in Midland, Mich.
“Remember, we're competing with inexpensive gas and oil that makes virgin material” less costly these days, Merrington said.
“I think the biggest hurdle to recycling right now is shale oil and shale gas and the price of oil dropping,” he said. When oil prices are higher, “recycling makes a lot of sense.” And when they are lower, “It's hard to make that sale.”
Plastics, compared with other typical materials in the recycling stream, also are not easy to recycle. Plastics reclaimers face challenges like no other, he said.
Factors such as additives, heat histories and even the mix of plastics collected can all complicate the job of plastics recyclers, he said at the Plastics Recycling in 2015 Workshop.
The workshop organized by the Plastics Environmental division of the Society of Plastics Engineers brought together folks on Feb. 23 in Dallas to talk about plastics recycling.
“Even plastics that have the same name may be different from different producers,” Merrington said. “The way they are produced can give us different properties.”
The properties of recycled glass, steel and aluminum, for example, are essentially equivalent to their virgin material counterparts. But that's not always the case for plastics.
Infrastructure, ultimately, is a key in successfully recycling plastics, he said.
“It's the infrastructure. If there's infrastructure, then I believe that the scientists and the engineers are capable of solving any issues,” Merrington said. “But it's the collection infrastructure.”
He pointed to New York City's recent decision to ban expanded polystyrene as an example in his view.
“As we saw the problem in New York, there's no way to collect the expanded polystyrene and get it to where you needed to get it and that's the issue. And keep it separated,” he said.
While the markets for recycled steel and aluminum are pretty clear, that's not always the case for certain recycled plastics.
Recyclers have to consider the relative interest in their end product. Just because a plastic can be recycled doesn't mean there's a viable market for the material, he said.
PET and high density polyethylene have well-established recycling markets and enjoy the highest recycling rates. And polypropylene is seeing a great upswing these days.
But other resins recycled at a much lower level, especially when they are mixed.
Despite the challenges facing plastics recycling, Merrington believes there remains a great opportunity to capture more of the material. That's because, he said, 87 percent of the plastics produced are landfilled within eight weeks.
“As recyclers, we see that as a huge source of material we can go after,” he said.
“If there's design for engineering, there's design for recycling, if those concepts are maintained, if the infrastructure exists to recovery the materials and get it to the person who can do the processing, then I think we'll see successful recycling,” he said.