New bio-resin could enable truly circular 3D printing

Researchers at Birmingham University have developed a new type of bio-based resin that can be 3D printed in high definition then recycled back into its constituent parts and reprinted.

A 3D-printed complex part made from the entirely bio-sourced feedstock
A 3D-printed complex part made from the entirely bio-sourced feedstock - Birmingham University

Described in the journal Nature, the photopolymer resin uses a feedstock derived from lipoic acid, a naturally occurring fatty acid molecule commonly sold as a dietary supplement. The Birmingham team made a combination of two monomers from the lipoic acid from which they were able to make a resin that could be recycled either back into the monomers, or back to the original molecule for recycling.

As part of the study, the researchers completed two printing ‘recycles’ with the material but anticipate that further recycles would be possible. Reprinting the resin requires the addition of just a small amount of photoinitiator to maintain the material’s curable properties.

“Our approach is an important step away from relying on 3D-printable resins made from petrochemicals, which cannot be efficiently recycled,” said lead researcher Professor Andrew Dove, from Birmingham’s School of Chemistry.

“While we still have improvements to make to the properties of the new resin, this research opens up exciting new avenues for development.”

Uses for the material could include industries where rapid prototyping is used to test products before moving to mass production. Although currently the material is more flexible than might be commonly used in industry, future applications could include automotive parts, medical and dental components, and even jewellery design.

“Enabling recycling within the light-mediated 3D printing industry is essential since it is a rapidly expanding method for materials production,” said co-lead researcher Assistant Professor Josh Worch.

“We now have the prospect, with our technology, to help ensure that recycling becomes a built-in feature of 3D printing.”

University of Birmingham Enterprise has filed a patent application covering the resin and its use in 3D printing.