McDonald's waste cooking oil converted into 3D print resin by Canadian professor

Feb 21 2020, 2:38 pm

It’s widely acknowledged that, although mouth-watering, fast food has its downsides — the amount of grease that pools at the bottom of the paper takeout bag, for instance.

But that oil is exactly what University of Toronto Scarborough Professor Andre Simpson has used to break ground in the realm of 3D printing.

The reason this conversion is possible today is due to the type of fats that are used in fast food restaurants today. Currently, these spots rely on unsaturated fats, which are better for the body than the saturated fats used in the past.

Unsaturated fats, Simpson tells Daily Hive, are healthy for humans because they can be easily converted into other forms for use in the body.

“Similarly these same reactive sites can be cross linked to form a plastic,” he says. “We tag the fats with molecules that react with light and join the fats together to make a solid plastic.”

Simpson says that if this had been attempted 30 years in the past, when fast food chains used saturated fats, this cross-linkage wouldn’t have been possible. But today, when the importance of finding sustainable alternatives to our everyday practices is perhaps at its most pressing, the option exists.

And it is, in fact, sustainable. Simpson says that the plastic begins to biodegrade when buried in soil.

“In this case what is healthy for us is also good for the environment.”

Plastic butterfly derived from the waste cooking oil in Simpson’s lab. (University of Toronto)

The products of Simpson’s discovery have been tested and found to be stable under “normal conditions,” thus far, in terms of durability. So creations made through 3D printing with this type of resin aren’t going to particularly flimsy or fragile.

He tells Daily Hive that he hopes his study will encourage further research into the conversion of used oils. It’s his goal that recycled oil might be transformed into printable or photocurable resins on a commercial scale.

And, per Simpson’s findings, it seems like the transition towards a more sustainable material such as this one wouldn’t break the bank either.

“In this study all the chemicals but one can be recycled, making the cost [about] $300 ($396.50 CAD) per tonne, [or 40 cents per litre] resulting in the recycled oil being priced competitively with even the cheapest everyday plastics.”

Much of the cost of recycling, Simpson explains, is the transportation of used oil. He says he hopes that this discovery could remove financial barriers, making it possible for oil to be reused and recycled.

Simpson says that it could be “transformative” for recycling programs if high-value commodities were able to be manufactured — and easily — from waste cooking oil.

Rajshree Ghosh Biswas, a PhD student in Professor Andre Simpson’s lab. (University of Toronto)

In this case, Simpson’s lab used digital light projection (DLP) 3D printing. This means that light is projected into the resin to make solid shapes. He says that as long as a user has a DLP printer, the recycled resin should print successfully.

After the prints are complete, the carbon should return to the soil through biodegradation, which closes the carbon loop, Simpson explains. All of this while avoiding the use of fossil fuels, which conventional plastics are derived from.

Simpson says the possibilities for creations that could come from this recycled resin stem far beyond plastic butterflies. He says that since the resin would set in sunlight, it has significant potential.

“Examples could be a plastic concrete that cures on site, a UV curing glue and as it floats on water, maybe even a self-curing plastic sheet, walkway, or cover,” he says.

Imagine: Strolling down a walkway 3D printed with resin made from waste cooking oil.

The future, it seems, might not be so far away. Just follow the recycled resin road.