From Fryer to Glue: Waste Cooking Oil Converted Into Polyethylene‑Like Plastic and Superglue

Scientists have developed a chemical process that transforms discarded restaurant cooking oil into recyclable polymers that mimic polyethylene and into an adhesive strong enough to tow a car in a demonstration test.

Researchers, including teams from the University of South Carolina, describe the method in a paper published in the Journal of the American Chemical Society. The approach repurposes long fatty acid chains in used cooking oil through a series of chemical reactions to build long polymer backbones that resemble those found in conventional polyethylene (PE).

The resulting materials show physical and chemical properties similar to PE: they can be flexible or rigid, and their mechanical strength is comparable to conventional plastics made from fossil fuels. By controlling the polymer architecture—whether backbone chains are linear or branched—the team tuned material properties: linear polymers pack tightly and are stiffer, while branched chains yield more flexible plastics.

Some polymers produced by the process exhibited adhesive properties. In a notable demonstration, researchers bonded two stainless-steel plates with the polymer; the joint supported up to 123 kg (270 lb), and the glued plates stayed intact while towing a sedan up a gentle incline.

Potential Applications and Sustainability

The authors suggest the waste-derived polymers and adhesives could be useful in packaging, automotive components, medical devices, electronics, and other areas where PE-like materials or strong bonds are required. Because the feedstock is non-edible waste oil, the approach aligns with circular-economy principles and could reduce reliance on fossil-derived feedstocks for common plastics.

“Waste streams offer a potentially attractive alternative to biomass-derived feedstocks [to make plastics],” the researchers write, highlighting the method’s promise for sustainable materials innovation.

While the laboratory-scale results are encouraging, further work will be needed to assess large-scale production, lifecycle emissions, recyclability of the new polymers, and economic feasibility before commercial adoption.