Vitrimer Chemistry Brings Reversability to Thermoset Resins

Techstorm (Shanghai, China and Denver, Colo., U.S.) has developed a vitrimer-based recyclable epoxy pultrusion resin system aimed at closing the recycling gap in the wind energy industry.

As wind energy capacity expands, so does the disposal challenge for large wind turbine blades (WTBs), most of which relies on thermoset resins that are not reversible or recyclable by conventional means. Vitrimers, on the other hand, are a class of polymers that are reversible, while also retaining the advantages of thermosets — strength, durability, and chemical and temperature resistance. Moreover, their base epoxy chemistry remains unchanged. Dynamic covalent bonds inserted into the epoxy matrix allow the cured resin to break down when exposed to a targeted degradation solution. This ensures that customers are able to use familiar epoxy resin systems rather than introducing a new chemistry that would require long-term testing and validation.

Vitrimer-based recyclable resins degrade into oligomers that can be reused as chemicals or additives, while recovered fiber reinforcements can be reprocessed into compounds for applications such as injection molded fiber-reinforced polymer (FRP) parts.

Techstorm’s patent-pending, vitrimer-based pultrusion epoxy resin systems are designed to recycle at temperatures as low as 80°C using a nonhazardous targeted degradation solution. Developed specifically for WTB carbon fiber spar cap planks, the resin designed to enable recovery of recycled carbon fiber reinforcements at end of life, as well as immediate recycling of manufacturing waste generated during pultrusion and WTB production.

Techstorm says the same technology platform is being extended to infusion resins, along with urethane- and acrylic-based structural adhesives, with the aim of enabling recyclability across all parts of FRP components, including bonded accessories, working toward full wind turbine blade recyclability.