A breakthrough in the recycling of epoxy resin-based plastics has been achieved by researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa). Epoxy resins are used in many products, including wind turbines, but their tightly cross-linked polymer chains have made them difficult to recycle. According to Wenyu Wu of Empa, “Today, fibre-reinforced plastics are practically not recyclable, except under extreme conditions that damage the fibres. Once they have served their purpose, they are burned or disposed of in landfills.” However, the Empa team has developed a fully recyclable plastic by adding a phosphonic acid ester molecule to the epoxy resin. This creates a tight mesh of phosphorus-carbon and phosphorus-oxygen bonds that can be reorganised at high temperatures, allowing the resin to be melted and reused.
The added molecule was originally developed as a fire retardant, making the resulting plastic less flammable than conventional versions. The Empa researchers believe that the innovative resin could be ideal for coating wood, producing a clear, robust surface that is also fire-resistant. Heat and pressure could even be used to repair damage such as scratches. In the longer term, the team aims to develop a composite material in which both the fibres and the plastic matrix can be recycled separately.
This development could have significant implications for the use of epoxy resins in a wide range of products, reducing waste and environmental impact. The research has been published in the Chemical Engineering Journal.
