A University of Regina professor who has spent decades researching how to recycle waste turns her attention to disposable face masks.
It’s their way of tackling a seemingly insurmountable, global problem caused by plastic personal protective equipment.
“I grew up on a farm, so we’re used to taking bail or twine and barbed wire to fix things,” Denise Stilling said. “Repurposing and repurposing is part of my DNA as a Saskatchewan farm girl.”
Stilling, an associate professor of mechanical engineering, has been experimenting for years with melting down waste products like old tires and sacks of grain into new materials like cobblestones.
When face masks were made mandatory in certain public places to slow the spread of COVID-19, she found her next challenge.
“When the pandemic hit and you saw all these masks littering the sidewalks and coming into our waterway, I went — let’s make masks.”
Hundreds of billions of masks in the trash
A 2020 study found that 129 billion masks were being used around the world every month at the time.
Many of the disposable masks are made from polypropylene plastic, a material that will not degrade for hundreds of years. Although personal protective equipment is a means to slow the spread of COVID, researchers and environmentalists have highlighted the damage plastic has been causing since the pandemic began.
Stilling hopes that may change.
“What a great opportunity as we look at our filled landfills,” she said.
“If we don’t have to worry about pollution, we can use sand and dirt as an additive, we have a raw material source that costs us next to nothing.”
Face masks: a baking ingredient?
A University of Regina basement lab contains more than a dozen garbage bags and Tupperware containers full of used masks. Stilling collected them from bins on campus.
She waits a considerable amount of time before using them to allow the virus to die off and allow her to safely handle the material.
First, she removes the ear loops and metal nose piece. Then she manually cuts the masks into strips. These strips go into a shredder, which pumps out a fluffy material.
Then Stilling mixes the lint with other waste products, such as used tires and sand. She also adds olive oil to bind them.
This mixture goes into a mold that bakes in a convection oven at 200 C for two and a half hours.
The resulting material comes out in a tile shape. Stilling then tests this material for stretch and strength.
“If it’s something brittle,” she said, holding up a thin tile, “then, as you can see, that would make a great clipboard. I can make rulers out of it.”
Stilling is working on different recipes. The material can be made into anything from countertops to pavers, depending on what’s using it, she said.
Little help for the future
Stilling does not do the work alone. Since autumn 2021 she has been recruiting doctoral students to carry out tests and experiment with combinations.
Some students say this work is important because their generation will be forced to deal with plastic pollution.
“Right now there is a greater awareness among people about pollution,” said Anaamalaai Annamalai Senthilnathan, a 24-year-old graduate student who is helping with the experiments.
“Most places are banning single-use plastic and looking for alternatives. That’s a solution, but what do we do with the plastic that’s in place right now? We have to recycle it.”
Stilling said she is doing her part to help the environment by developing the prototypes and the materials. She hopes others, like entrepreneurs or governments, can take the next step: do something with it.
