New resins made from sawdust, straw, and other woody waste could be up to 76% stronger than the fossil‑based glues that hold together strong, lightweight materials used in the construction, transportation, and renewable energy industries. The sustainable glue alternatives could make it easier to recycle the heaps of trash produced by those industries.
High-performance composite materials are essential for modern car and aircraft bodies, wind turbine blades, flooring and roofing materials, and electronics. These composites, known as epoxy thermoset plastics, are made of glass or carbon fibers held together with epoxy resins.
Epoxy resins are tough glues derived from fossil fuel sources. They have big energy and carbon footprints. And the reason they are ideal for advanced composites is also what makes these materials notoriously difficult to recycle. The cured resins form tough cross-linked chemical bonds that are very hard to break.
Recycling the composites is possible, but it takes expensive processes using specialty chemicals, and it’s hard to scale up. This is why wind turbine blades, aircraft parts, and electronic boards and other components mostly end up in landfills.
So researchers at the University of Oulu, Finland made plant-based epoxies that match the performance of conventional epoxies. One of the two key building blocks of an epoxy is a compound called bisphenol-A. The research team replaced that with a recyclable alternative, furfural-derived diepoxy, which they made from biomass.
Woody biomass is composed of cellulose, hemicellulose and lignin. The researchers converted these compounds into furfural, made furfural-derived diepoxies, and used them to create glass fiber reinforced composites. In laboratory tests, the bio-based composites were significantly stronger and tougher.
The composites are also recyclable. Chemical reactions with a potassium carbonate catalyst broke the bonds in the furfural, which made it easy to separate the components of the composite. The furfural epoxy broke down into its building block, which could be reused to make the resin.
“This work presents a conceptually new and a promising strategy to develop high-performance composites with enhanced sustainability and recyclability,” the team writes in their paper published in Composites Part B: Engineering.
Source: Reima A. Terho, Bianca Dal Pont, Tuomo P. Kainulainen et al. Circular composite materials: Biomass-based furan epoxies with high-performance and closed-loop recyclability, Composites Part B: Engineering, 2026.
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