Butterfly 3D printed in food waste oil-derived resin. Source: Don Campbell/University of Toronto ScarboroughResearchers from the University of Toronto Scarborough are turning cooking oil waste into high-resolution resins for 3D printing.

Researchers discovered that the molecules found in standard 3D printing resins are similar to the fats in cooking oils. As such, the team recovered cooking oil waste from a local McDonald's to demonstrate its performance as a 3D printing resin.

To convert the waste oil, the team acrylated the cooking oil in a one-step chemical process that turned 1 liter of cooking oil into 420 milliliters of 3D printing resin. Following the addition of a photoinitiator, the 3D printing resin was then used to create a 3D printed plastic butterfly that was both structurally and thermally stable.

There are many implications for such a development, according to the University of Toronto Scarborough team. The process could result in a potential cost savings for the additive manufacturing industry. Currently high-resolution resins for 3D printing can cost $525 per liter versus the cost of converting food waste oil into resin that costs just $300 per tonne, according to its developers.

Additionally, the process offers a solution for the disposal of food oil waste, which is difficult to dispose of and can lead to sewer build up, potentially contributing to so-called fatbergs that clog sewer systems.

Additionally, the 3D printing resin derived from cooking oil fat is biodegradable. Consequently, products manufactured in the oil will likely degrade faster than 3D printed products produced in standard resins. The University of Toronto Scarborough team discovered that a product produced in the oil-derived resin degraded by 20% after it had been buried in soil for two weeks.

The study, "Direct conversion of McDonald’s waste cooking oil into a biodegradable high-resolution 3D-printing resin," appears in ACS Sustainable Chemistry and Engineering.