The University of Georgia recently released a study showing that an estimated 111 million metric tons of plastic garbage will pile up around the world by 2030. Plastic waste that could be recycled ends up in the oceans and in landfills, and there are plastics that can't be recycled at all.
Here & Now's Jeremy Hobson speaks with Jamie Garcia, polymer chemist at IBM, about how to make plastic that's easier to recycle and ways to improve the plastic recycling system. She says “not very much” of the plastic materials we use are even recyclable.
“In the U.S., we recover 8.8 percent [of plastic materials] to do various things at the end of its life with, which is quite low,” Garcia says. “So there's not very much that's recycled in the U.S.”
On why only a small percentage of plastics are recyclable
"When we invented plastics, they were invented and produced to be durable. So that in and of itself is the biggest challenge for actually being able to recycle some of these virgin plastic materials and get recycled materials that have the same properties. In addition to that there’s a lot of different varieties, and we have a method to recycling all of them, which doesn’t necessarily work equally for each for each type of plastic."
On mechanical recycling
"So that’s typically what people think of when they think of recycling. So that entails taking a plastic, cutting it down into small pieces, decontaminating it and washing it of all organics, and then melting it down and remolding it into the new product."
On chemical recycling
“Chemical recycling is a different approach where instead of using a mechanical process where you're physically melting an object and then remolding it, what we're doing is we're actually tackling breaking bonds at the molecular level. So we design catalysts, for example, to go after very specific chemical functional groups and the backbone of a polymer, for example. And so what that enables us to do is actually target each different type selectively and use a different approach to break down each different type of plastic.”
On the advantages of chemical recycling
“The advantages that you get: selectivity. So you're able to go back. In an ideal world, chemical recycling would yield the monomer, which is the basic most fundamental starting material of any plastic. And what that allows you to do is if you take that monomer and then repolymerize it — so you turn it back into a plastic again — you'll get a material at the end with identical properties as the virgin material. So in other words, you don't have this issue that we have right now with mechanical recycling where you get a diminishment in materials and you have to downcycle.”
"Chemical recycling is a different approach where instead of using a mechanical process where you're physically melting an object and then remolding it, what we're doing is we're actually tackling breaking bonds at the molecular level."Jamie Garcia
On why chemical recycling has very limited availability
“Right now, chemical recycling is very isolated to different processes that require very high temperatures. So a lot of times what happens is if you've ever heard of thermal cracking of a polymer, that is what falls into the chemical recycling bucket right now of technologies, and what that usually requires is an energy input of 500 to 900 degrees Celsius. You usually have a catalyst in there and then once you depolymerize it, you oftentimes will get a mixture of different products that you then have to separate.
"So in the end, the processes that are in place right now are oftentimes more expensive, and so they're not economically feasible compared to things like mechanical recycling. So the challenge there is going to be finding new catalysts that can act at lower temperatures and have better selectivity, so that instead of getting a mixture of products, get maybe just one thing, preferably the monomer, to be able to reuse.”
On the difficulty of creating plastics that are chemically recyclable
“I think it's going to be a little bit tough because a lot of the virgin materials that we use, the commodity plastics ... they've been used for a long time, and a lot of them they've been specialized for a very specific application. Industry really likes using it. They're cheap materials as an alternative to other types of materials. And so I think the hurdle there is really going to be getting industries to wrap their head around using a different type of material that has equally as good properties and performance as materials that they're used to using and then getting the cost down over time. So there's a little bit of an energy of activation there to go into an area where you're going to start using new materials that they're not necessarily familiar with.”
This segment aired on July 16, 2018.
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