Towards Sustainable Recycling of Epoxy-Based Polymers: Approaches and Challenges of Epoxy Biodegradation

Composites are especially important for the development and implementation of sustainable technologies such as wind power, energy-efficient aircrafts, and electric cars. Despite their advantages, their non-biodegradability raises challenges for the recycling of polymer and composites in particular.

University of Hamburg, Hamburg, Germany

Epoxy polymers are widely used in various industries, e.g., as coatings, adhesives, and for lightweight construction due to their unique properties such as high strength, chemical resistance, and adhesion to various surfaces. Therefore, one of the most prominent applications is their use as matrix material in fiber-reinforced composites, which are heavily employed in the aerospace sector. However, the disposal of epoxy polymers and composites thereof has become a significant concern due to their recalcitrant nature and the adverse environmental effects caused by traditional recycling methods.

In this context, the overall production of plastic waste is projected to double within the next 20 years, with only 18 percent currently being recycled, leading to the deposition of around 12,000 Mt of plastic waste in landfills and the environment by 2050 (see figure 1). Even though epoxy polymers only accounted for a rather small share of the global plastic production volume of around 7.1 percent in 2021, the demand for fiber-reinforced polymers is steadily increasing. This is closely linked to emerging sustainable technologies such as off and on-shore wind power plants or electric vehicles that rely on lightweight construction materials for increased efficiency. To cover the resource demand of the composite industry and to reduce the environmental impact of accumulated epoxy waste, there is an urgent need for the development of sustainable recycling methods.