Bulletproof vests and other super-strong materials could become tougher and more environmentally friendly with the help of so-called “al dente” fibers. Researchers from ETH Zurich have developed a method for spinning polyethylene fibers from natural fats, such as oils from olives and peanuts. These materials can also be used for many other tasks that require strength.

Polyethylene fibers made with olive oil could help make super-durable materials even stronger. Image credit: American Chemical Society.But the researchers says that making the fibers with today’s commercial processes has drawbacks. For example, one of the methods of producing ultrahigh-modulus/ultrahigh-strength fibers and films—gel spinning of "virgin" (that is, never molten or fully dissolved), ultrahigh molecular-weight polyethylene—requires large amounts of solvents that are flammable and toxic.

The research group, led by Theo Tervoort and Paul Smith from ETH Zurich, wanted to find more environmentally friendly materials to produce the fibers. They did so by replacing the hazardous solvents with natural, safer alternatives, including extra virgin olive oil, peanut oil and stearic acid, which is a substance found in animal and vegetable fats. Using relatively "poor" solvents such as these suggest recovery and environmental advantages. The researchers report a more efficient process than current methods, with the fibers up to two times stronger than commercially available products.