Well if this isn’t an innovative reuse of fast food waste, then I don’t know what is. Researchers from the University of Toronto have achieved an exciting first by turning used cooking oil from McDonald’s into a high-resolution 3D printing resin. The material, which is also biodegradable, could provide a cheaper and more eco-friendly alternative to traditional 3D printing resins.
Plastics made from synthetic chemicals pose an environmental threat. Though they are consumed on the regular, those that are not recycled are destined to end up in landfills because they are not biodegradable. Having plastic materials made from nature-derived materials could pave the way to more eco-friendly consumption.
“The reasons plastics are a problem is because nature hasn’t evolved to handle human-made chemicals,” explained Andre Simpson, a professor at U of T Scarborough’s Department of Physical and Environmental Sciences. “Because we’re using what is essentially a natural product—in this case fats from cooking oil—nature can deal with it much better.”
Simpson was inspired to develop the oil-based resin after acquiring his own 3D printer a few years ago and noticing that many molecules in commercial resins were similar to those in cooking oils. After reaching out to many fast food chains, Simpson was eventually contacted by McDonald’s, which provided him with used cooking oil from its locations in Scarborough, Ontario.
With the used deep frying oil, Simpson and his team employed a one-step chemical process to transform the oil into resin. The process successfully turned one liter of oil into about 420 ml of resin.
The U of T team tested the resin by 3D printing a butterfly. Impressively, the sample print demonstrated that the cooking oil-based resin could create parts with features as small as 100 micrometers. The butterfly also proved to be structurally and thermally stable when exposed to warm temperatures.
“We found that McDonald’s waste cooking oil has excellent potential as a 3D printing resin,” added Simpson, who is also the director of the Environmental NMR Centre at U of T Scarborough.
In addition to providing a more eco-friendly alternative for resin 3D printing materials, the biodegradable resin also offers a novel solution to cooking oil waste, which itself is a major environmental concern. Used cooking oil derived from homes and restaurants is difficult to dispose of and can cause serious clogs in sewage pipes as fat builds up.
Transforming the oil into a high-resolution 3D printing resin is a high-value solution that could actually make it easier to recycle used cooking oil. That is, because 3D printing resins are a high value commodity, it could help alleviate the financial barriers of recycling cooking oil waste.
In terms of cost, the oil-based resin can reportedly be made for as little as $300 per tonne—today’s high-resolution resins cost upwards of $525 per liter. The material can also be cured in sunlight, which creates additional application opportunities. In terms of biodegradability, the researchers found that two weeks after burying a sample print in soil, the part had already lost 20% of its weight.
“If you bury it in soil, microbes will start to break it down because essentially it’s just fat,” Simpson explained. “It’s something that microbes actually like to eat and they do a good job at breaking it down.”
The research project is supported by the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, the Government of Ontario and the Krembil Foundation.