The world has been smacked in the face with plexiglass, or more accurately shielded from other faces. When the coronavirus pandemic hit and the World Health Organization recommended using glass or plastic barriers, plexiglass went from an industrial material to an everyday object.
Restaurants put gleaming new sheets of plastic on takeout pickup windows to protect their tellers. Grocery stores and pharmacies affixed sheets to cash registers. At farmers’ markets, city parks and out on walks in the neighborhood, it’s not uncommon to see at least a few sneeze screens among the hordes of masks.
According to a store manager of TAP Plastics quoted in a National Public Radio article, a year's supply of the plastic sheets was gone in two months.
"The whole market just went absolutely crazy," David Smith, the circular economy program lead at Lucite, told GreenBiz. "It was like a sixfold increase in orders." Lucite is an international seller and manufacturer of acrylic plastic products.
According to Marc Tracey, communications lead at Roehm America, the makers of Acrylite and Plexiglas (the brand, not the overarching product), saw demand increase 12 times initially, with things leveling off to five to 10 times its normal demand.
The whole market just went absolutely crazy. It was like a sixfold increase in orders.
It’s clear (haha, get it) that plexiglass barriers aren’t going anywhere while the threat of COVID-19 remains. And with some schools welcoming students back to classrooms, demand could rise again for interesting and innovative barriers that protect students and teachers.
Plexiglas (with one s) is actually a brand name. But like Kleenex is to tissues, it also has become the catchall term for a clear plastic sheet of acrylic. But mostly what people refer to as plexiglass is polymethyl methacrylate, or PMMA. That material can come from a few suppliers including Roehm, Lucite and Perspex.
Before the virus, demand for such plastics had been decreasing, as innovation allowed for thinner sheets in appliances such as TVs. As demand spikes, there’s a need for a sustainable, recyclable and ultimately circular option. Thankfully, that option could be imminent.
PMMA has beaten other plastics to circularity
Currently, industrial PMMA waste — such as swarf, plastic shavings made from cutting and smoothing the PMMA — and end-of-life PMMA products are downcycled into depolymerized MMA (dMMA), mainly used for coatings that can’t be recycled again. That only give the PMMA one extra life before heading to the landfill.
The screens being deployed all over the world to cope with coronavirus won’t be applicable for such recycling — dMMA requires high quality and pure PMMA.
"There’s going to be thousands and thousands and thousands of sneeze screens coming back," Smith said. "They will not be suitable for the dMMA because the chances are they will have been wiped with some kind of alcohol cleaning product every day for years and will start to deteriorate. So [dMMA] will be pretty useless."
So a new type of recycling is the goal. Unlike PET, its sister plastic in the bottle industry, PMMA has a clear path forward to circularity. Lucite is working on this type of fully circular PMMA with Oregon-based company Agilyx.
According to Smith, PMMA can be turned back into its monomer, methylmethacrylate (MMA), using thermal depolymerization. This thermal depolymerization can create virgin-like MMA, the holy grail of a circular plastic.
By heating the plastic to a certain temperature, the chemical bonds break apart, creating a crude oil. And because the resulting oil can be purified, high-quality untainted PMMA isn’t needed. Instead, the process can use a wide variety of feedstocks, including deteriorating end-of-life products.
"The circularity market for PMMA is more mature, as a percentage of market share, for PMMA than PET," Chris Faulkner, CTO of Agilyx, wrote in an email. "PMMA depolymerizes nicely into its monomer MMA through advanced recycling at high concentrations – making circularity and recovery of materials straightforward."
This thermal depolymerization can create virgin-like MMA, the holy grail of a circular plastic.
Agilyx develops advanced recycling technology, specializing in polystyrene, also known as styrofoam. According to Agilyx, its scientists have studied hundreds of plastics to understand the different properties. They realized that both polystyrene and PMMA have a similar ability to depolymerize into their monomers chemical so the method Agilyx had perfected in polystyrene could be transferred over to PMMA.
"The fact that Agilyx has proven that they can successfully depolymerize polystyrene back to styrene, that gave us 99 percent confidence that we could do the same with PMMA and MMA," Smith said.
After purification, Lucite can create its own circular PMMA products or sell the recycled MMA. "Some of our customers are already screaming for recycled MMA," he said.
Lucite plans to have a PMMA recycling plant open in 2023 somewhere in Europe. Another organization, The MMAtwo Project, is working on constructing a supply chain for recycled MMA in Europe.
Can PMMA stand out in the recycling stream?
Like with most recycling innovations, this strategy for making plexiglass circular could be thwarted by consumers. Today, only 30,000 tons of PMMA waste is collected to be recycled, about 10 percent of yearly production. Right now, that 10 percent is mostly signage, where Smith says there is an established market. Before the pandemic, Lucite was focusing on creating a market to incentivize industrial businesses to return recovered PMMA.
According to Smith, a common example is the auto industry. PMMA is incorporated into taillights, but they are attached to a polycarbonate that can’t be recycled in the same way.
"We need to help create a market so the [mechanics] will want to dismantle the taillight," he said.
Right now a junkyard won’t spend the time, money and resources separating every taillight from cars for a recycling stream that doesn’t exist. The explosion of PMMA screens in the consumer market is also creating another new obstacle when it comes to waste management.
"To the consumer, plastic is plastic," Smith said. "I think the challenge for PMMA is to stand out from other plastics as fully recyclable."
Smith said Lucite is already working on a mini-project to understand how it might get those sneeze screens back from customers on the day we jubilantly remove them from between our faces and rejoice the end of the pandemic.