Plastics: Rising To the Challenge

05/24/2022
By Ed Brennen

At roughly three times the size of France, the Great Pacific Garbage Patch is the planet’s most glaring scar from our dependency on plastic.

“You hear about global warming and how plastics have a bad reputation because of bags and straws floating around,” says plastics engineering graduate Terri-Ann Heang ’22. “I used to think, ‘Why are we making more plastics? They’re bad for the world.’ But everything is made out of plastics, even our clothes. You can’t really avoid it, so you might as well make the best use of it to help the planet.”

Students in the Francis College of Engineering are learning to do just that. Through senior capstone projects, plastics engineering majors are rolling up their sleeves and working on ways to recycle plastics, be it for 3D printing filament or food packaging.

And this year, the college introduced a new, required first-year course, Introduction to Polymer Sustainability. Taught by Prof. Margaret Sobkowicz-Kline, the course provides students with a foundation in the principles of environmental sustainability and the relationship of polymers and plastics to the environment.

“There’s quite a bit of bad press—and bad reality—about plastics in the environment,” says Sobkowicz-Kline, who researches renewable polymers and is a member of UML’s Climate Change Initiative. “We need plastics engineers to solve these challenging problems. Who else is going to solve them?”

Sobkowicz-Kline discusses the pros and cons of plastics with students “because these aren’t clear-cut issues,” she says. In one class this spring, she covered everything from the carbon cycling process to producing lighter-weight electric vehicles.

While the course is intended for first-year students, several upper-class students jumped at the chance to take it this spring.

“Plastics are going to be in the environment and in the world, so how can we make them better?” asks Kareem Halwani-Plaza, a senior plastics engineering major from Watertown, Massachusetts, who is also looking ahead to the career implications. “Sustainability is where the money is. If you can make plastics more efficient, that’s the million-dollar idea.”

Here is a look at three of this year’s senior capstone projects that take on the challenge of plastics sustainability:

Pilot Scale Multilayer Extrusion With Recyled Content

Terri-Ann Heang (Lowell), Jacob Landry (Uxbridge, Massachusetts), James Nordberg (Attleboro, Massachusetts) and Michael Pugatch (Westford, Massachusetts) with Prof. David Kazmer

Two years ago, Industrial Advisory Board member Jo Ann Ratto ’88, ’93, a since-retired research engineer at the U.S. Army Natick Soldier Systems Center, arranged to have a multilayer extrusion machine donated to the Plastics Engineering Department. Originally used to make packaging for soldiers’ MREs (meals ready to eat), the machine sat disassembled in Room 101 of Ball Hall on North Campus for nearly a year.

This year, it has been brought back to life by a senior capstone team, which is working with Prof. David Kazmer to see if the machine can produce multilayer film containing recycled plastic.

“It’s a fairly new concept,” Heang says as she explains how plastic pellets are fed into five extruders, each of which produces a layer that goes through the machine “like rolling taffy in a candy shop” to produce a five-layer film.

Because recycled materials are not clean enough to be used for the film’s outer layers for food or medical applications, the students have experimented with using the recycled plastic on the inner layers and new material on the outside.

Landry, who has taken several sustainability-related classes at UML, likes knowing that the team’s work “hopefully will have an impact on the world’s recycling problem”—while also giving him a leg up in the job market.

“There’s a lot of groundbreaking technology in sustainability right now, so it’s important to have that experience,” he says. “If you can become specialized in a new market for sustainable materials, that’s a great opportunity.”

Pugatch adds that just getting the machine up and running was a valuable experience.

“Usually, you work on a system that’s already put together. We definitely had our work cut out for us,” he says.

The group is also creating standard operating procedures so that future students will know how to run the equipment.

Kazmer and Ph.D. student Sixtus Nzeh are part of a research team that recently received a $2 million National Science Foundation grant to develop the multilayer films. Johns Hopkins and Georgetown universities, the Air Force and the National Institute of Standards and Technology are the other team participants.

“It’s an important problem to solve,” says Nordberg, who appreciates the opportunity to work on a sustainability-related capstone. “Being able to run this system and test it out with recycled materials can help improve the future of films, which are used so much for food and packaging.”

Chemical Recycling Of High-Value Plastics From Electronic Waste Using Safer Solvents

Evan Yu (Brookline, Massachusetts) with Asst. Prof. Wan-Ting (Grace) Chen

An estimated 50 million tons of electronic waste—old computers, phones and TVs that people no longer want — ended up in the world’s landfills last year. About 20% of that e-waste was plastics treated with flame retardants, which make them difficult to recycle.

For his senior capstone and Honors thesis project, Evan Yu is treating crushed pieces of e-waste with a variety of chemical solvents that dissolve the plastic and remove the hazardous flame retardants. The plastics can then be brought back to a solid form and potentially reused.

“No one really focuses on electronic waste — what happens when you throw away your old TV,” says Yu, who joined Chen’s lab as a sophomore. “Over time, these additives and flame retardants in plastics get released and go into the environment, and that causes a big environmental hazard.”

Yu, who is now pursuing a master’s degree, says the senior capstone project has been a great way “to match the theory learned in the classroom with actual experiments.”

Foam 3D Printing With Recycled Polyethylene

Stephen Hart (Boston), Yrvanie Joseph (Randolph, Massachusetts) and Zarek Nieduzak (Bridgewater, New Jersey) with Asst. Prof. Amir Ameli

With 3D printers now available for less than $200, more at-home hobbyists are giving them a try. Most printer filament (the “ink”) is made out of polylactic acid, but a capstone group is working with Asst. Prof. Amir Ameli to see if recycled polyethylene can be used instead.

“Every time plastics are recycled, their molecular weight breaks down, so the properties are worse,” Nieduzak explains. “With recycled high-density polyethylene, it warps and shrinks” when used in a 3D printer.

To combat this degradation, the students are adding a foaming agent—microspheres of liquid hydrocarbons in a polymer shell — to recycled polyethylene pellets in a single-screw extruder to make a filament. When the filament is heated in a 3D printer, the microspheres’ outer shells melt, allowing the gas inside to expand and produce a foam structure.

“Seeing this project through has been amazing,” Hart says. “To take an idea and get it to actually work is something I’ll take with me into my professional career, for sure.”

Yrvanie Joseph, who has taken on sustainability-related projects during two internships at Procter & Gamble, traces her interest in the topic to a mission trip she took with her mom to Haiti the summer before her freshman year at UML.

“I saw a lot of trash in the streets, most of it plastic waste,” says Joseph, who switched her major from biomedical to plastics engineering so “I could focus on that issue.”

Ameli enjoys meeting with the students every week to discuss their capstone’s challenges and solutions.

“They learn by doing the hands-on work,” he says. “They get to try so many things—most of the time it doesn’t work, but sometimes it works. Those are the ‘aha’ moments that are really good.”