The End of Plastic

César, Expansion n°37, 1972

Peak oil means peak petroleum products, which could mean the golden age of plastic fabrication is already past

Debbie Chachra is a materials scientist. Working out of Olin College — an engineering school set up like a liberal arts college — she teaches undergraduates, researches better ways of teaching undergraduates, and does strange things with bees. Beyond her professional duties, she runs Daily Idioms, a Tumblr of striking ideas.

Chachra has a knack for noticing and pointing out the underlying forces that shape the stuff our stuff is made of and how the properties of that stuff in turn shapes our tech and so our culture. Last year, Warren Ellis asked her to write about whatever was on her mind. The result was a fascinating exploration of the consequences of peak oil for industrial design. She called it "peak plastic." Tim Maly talks with Chachra about peak plastic, the challenges of the 3-D printing revolution, and honey bees.

Tim Maly: I've been wanting to talk to you about peak plastic for a while. As I understand it, the idea is that though plastic accounts for less than 10 percent of petroleum use, it is used in a huge portion of the materials that surround us. If it's true that we're running out of oil (and it seems like we are) then not only are we facing an energy crisis, we're also facing a materials crisis. Is that about right?

Debbie Chachra: I'm not sure if crisis is the word that I would use. It's certainly an opportunity to think hard about what we use to make things. The first thing that it's worth noting is that the materials around us are mostly invisible, and plastic more than most.

At the Museum of Science and Industry in Chicago, they have a German U-boat from World War II on display, and you can walk through it. By far the most striking thing about it, for me, was the complete absence of plastic. The cupboards were wood with glass windows, the dishes inside made of metal. And this in an environment that was constantly wet. The only synthetic polymer that I saw inside the submarine was used to wrap the codebooks that went with the Enigma machine.

I'm writing this in my living room, and just looking around I see: my furniture is upholstered in synthetic textiles, my bookshelves are made with laminate, my lamp has a plastic diffuser, the walls are covered in paint made with synthetic polymers, the wooden floor has a polyurethane finish, one of my chairs is made of polypropylene, the dustjackets are made of coated stock, and there is a big stack of records and of CDs. With the exception of the windows and a brushed stainless steel lamp, virtually everything I can see is either made of polymer or is coated in polymer. That's the difference between 2013 and 1945.

Now, granted, this is a very developed-world description. My parents' house in India looks quite different, and a shanty in a favela outside Rio would look different still. But I promise you that there's plastic to be found in both.

TM: How will this change if we start running out of oil?

DC: Well, before we run out entirely, the price of oil is likely to go up. Since one of the major virtues of plastic is how inexpensive it is, this will be an incentive to change how we do things.

The simplest thing is to change the feedstock to something like natural gas. This will need some retooling, but would otherwise be pretty straightforward. Polyethylene is already mostly made from natural gas, not oil. And that's likely to be an intermediate step.

TM: I wonder how much time that really buys us.

DC: That's a bit of an open question, but probably a decent amount.

But really, this is an opportunity to think about what should be made of plastic, and why. As the price of plastic creeps up, we can start bringing alternative materials online. A good example is switching disposable cutlery to bioderived, compostable plastics — there's really no reason why something that has a functional life measured in minutes needs to be made of something like polystyrene that essentially lasts forever.

It also means, I hope, that we get better at recycling and it becomes more cost-effective. It's not just about crunchy-granola save-the-earth stuff; it really offends my sense of efficiency as an engineer that most plastic just ends up sequestered in landfills. From a materials perspective, so many products are massively overengineered. So I'm hoping to see more cradle-to-cradle design with plastic.

TM: I'm reminded of peak whale oil and how kerosene distilled from petroleum saved the whales by giving humans something better than whale oil to burn.

DC: Ironically, we may very well find ourselves going in the opposite direction with plastics: from petroleum to biologically-derived polymers. The most promising area, I think, is the use of agricultural by-products as a feedstock: for example, feeding bacteria the waste material from palm oil production and having them synthesize biodegradable polymer.

TM: One of the darlings of future of materials stuff is the suite of technologies that allow (or will allow) desktop fabrication. I'm talking about 3-D printers, CNC lathes, laser cutters, wire benders and so on. There's a lot of excitement about how these new things will drive demand for new materials. Do you share in that?

DC: Rright now, I think the opposite is happening: that existing materials are driving demand for new manufacturing techniques, whether it's low-power lasercutters to cut fabrics for quilting, or easy-to-use wire benders, or figuring out how to 3-D print a wider range of materials.

To me, the last of those is a particular challenge. It's a central tenet of materials science that the material, how it's processed (such as the manufacturing technique), and its physical properties are inextricably linked.

TM: Today, when we talk about future of fabrication stuff, we mostly talk about a particular kind of 3-D printer. The most popular versions of the current tech that's caught everyone's imagination are essentially glue guns attached to servo motors, I'm thinking of devices like the MakerBot family.

DC: Right now, our additive manufacturing technologies just aren't very good compared to traditional technologies: it's why Shapeways specifies that "3-D printed products are intended for decorative purposes." As you might imagine, there is a lot of work going on to try and get better at 3D printing materials, and to bring new materials online.

Much as I'm fascinated by 3-D printing, there's a pretty serious catch, and it has to do with that processing/properties relationship. You can 3-D-print a Japanese sword out of steel, with sub-micron precision, but it still won't have the amazing properties of the forged version, which results in a carefully-controlled atomic architecture of steel and carbon atoms. More prosaically, the same is true for a plastic shopping bag—the act of drawing the polymer into a film orients the molecules, making it stronger and stiffer.

So one thing I'd love to see more of is people combining 3-D printing and traditional techniques, like printing out algorithmically-generated structures and using them as the positive mold for lost-wax casting.

TM: Even if people take on that second step, the first step mostly spits out plastic, which results in piles of non-biodegradable tchotchkes and failed experiments. I have these visions of the early years of computerized offices when the paperless office resulted in a sharp uptick of paper consumption because people would just print off a dozen copies of a document for a meeting, then trash them, then print off more next time they were needed.

DC: Scott Smith raised this issue over at Changeist—are we looking at a world full of "crapjects"? I think the evolution of printing and photocopying might tell us something about the evolution of 3-D printing. When photocopiers were new, you only photocopied what you really had to. If you had to do any serious printing or photocopying you went to a print shop like Kinko's, and got the professionals to do it for you, with their industrial-scale machinery. Two major things have changed. One is that the level of reliability of an office photocopier is infinitely higher: partly because they're just more robust, and partly because of how user-serviceable they are — I'm always amazed at the degree of design effort that has gone into making it easy for a Jane Schmoe like me to clear a jam. But the other important change is the design side. Almost every piece of software that has a print button is either WYSIWYG, has a print preview button, or both. These days it's rare that I print something and then need to re-print it because I messed up.

So I think of 3-D printing as at the stage of dot-matrix printing (yes, I'm old). There'll likely be the equivalent of Kinko's (Shapeways, for example, or even Staples, who are experimentally offering 3-D-printed papier-mâché), where professionals will print your objects for you. Eventually, 3-D printers will get robust enough and—more importantly—the usability of the CAD software will get good enough—that it'll make sense to have local machines. When that happens, we'll make fewer crapjects, just like we rarely have failed printouts. As I said above, what people get excited about is the ability to do things, and right now computer-aided design is still hard. Getting the materials you want is hard. Getting them to print at a high enough quality is hard. We'll need to solve those three problems before 3-D printing becomes widespread.

Of course, even my Very Serious printer/photocopier/scanner at work has reams of paper stacked beside it, and a recycling bin next to it. One of the promises of 3-D printing is distributed manufacturing, but that doesn't mean much if you're still plugged into a global supply chain for materials. So I'm pretty stoked by things like the Filabot, which lets you extrude waste plastic into printing filament. It's remarkably similar to the closed-loop, environmentally sustainable approach of a company like Preserve (who make your new toothbrush out of old toothbrushes).

I kind of want my future 3-D printer to be flanked with a bioreactor that makes plastic out of waste agricultural material, and with an extruder that takes both the bioreactor plastic and my failed objects as feedstock.

TM: You've done work with bees, specifically a bee that makes a very plastic-like material. Does that work relate to these problems at all?

DC: One of my side projects is looking at a type of plastic made by the Colletes family of bees. Unlike honeybees, these bees are solitary. Every spring, the female bees dig underground nests in which they'll lay the eggs. They consist of several tunnels that dead-end into nest cells, each about the size and shape of the last joint of your little finger. The bee lines the nest with a material that looks for all the world like cellophane; then she provisions the nest with a mixture of pollen and nectar, lays an egg, and seals it off. Over the course of the next year, the egg will hatch into a larva, eat the food, develop into an adult bee and, the following spring, dig itself out of the nest to continue the cycle.

The clear plastic nest cell lining protects the contents of the nest while it's buried in the dirt for a year, which is a pretty intense environment, especially in the temperate New England summers, where we get a decent amount of rain. The nest cells are made out of something chemically similar to polyesters, and are remarkably resistant to degradation — annoyingly so, if you're trying to analyze what it's made of! But they obviously degrade eventually, or else we'd be up to our eyeballs in all the nest cells made since the last Ice Age.

So I'm working with a microbiologist to try to find bacteria that degrade it. We're not really about the commercial side of it (although my friends tease me about wanting an army of bees to do my bidding). It's mostly a proof-of-concept: a plastic that's resistant to degradation under normal conditions, but when you're done with it, you can throw it into a bioreactor and break it down, instead of sending it to landfill.

It's possible that our material environment will look exactly the same after we run out of oil. But I think it's far more likely that we'll see a range of new polymers, that do a better job of filling niches. At least I really hope so.