Page 43 - Plastics News June 2024

FEATURE NEWS

Bio-based resins could offer recyclable future for 3D printing

A new type of recyclable resin, made from biosourced materials, has been designed for use in 3D printing ap-
plications.

n a study, published in Na- biomass, the recyclability of these is The feedstock for the process is made
ture, researchers from the still limited, because they rely on irre- from lipoic acid, a naturally occurring
University of Birmingham versible bonds being created when the fatty acid molecule that is commonly
showed that high-resolu- resin hardens. To break these bonds, sold as a dietary supplement. The team
tion, 3D printed structures can be additional chemicals have to be added made a combination of two monomers
manufactured from an entirely bio- at each stage, resulting in a ‘snowball- from the lipoic acid from which they
sourced feedstock. ing effect’, in which the only way to re- were able to make a resin that could
Once they have reached the end of cycle the material is to make more of it. be recycled either back into the mono-
their useful life, the products can be In contrast, the Birmingham-led team mers, or right back to the original mol-
recycled within an almost fully closed- has, for the first time, succeeded in ecule for recycling.
loop system. producing a photopolymer resin that In the study, the researchers complet-
Photopolymer resins, which harden can be printed at high resolution but ed two ‘recycles’, but anticipate that
– or cure – on exposure to light, are can then be broken back down to its further recycles would be possible.
commonly used in the manufacture constituent parts, recycled and reprint- Uses for the material could include
of bespoke 3D printed parts. Howev- ed, with the addition of just a small industries where rapid prototyping is
er, while technologies to improve the amount of photoinitiator to maintain used to test products before moving to
resolution of 3D printing and its speed the material’s curable properties. mass production. Although currently
of manufacture have advanced con- Lead researcher Professor Andrew the material is more flexible than might
siderably, the resins themselves have Dove said: “Our approach is an im- be commonly used in industry, future
changed very little since the process portant step away from relying on applications could include automotive
first emerged in the 1980s. 3D-printable resins made from petro- parts, medical and dental components,
The basic materials – usually epoxies chemicals, which cannot be efficiently and even jewellery design.
or acrylics – come mostly from petro- recycled. While we still have improve- University of Birmingham Enterprise
chemical feedstocks. Although some ments to make to the properties of the has filed a patent application covering
progress has been made in the use of new resin, this research opens up ex- the resin and its use in 3D printing.
more sustainable resins derived from citing new avenues for development.” Source – MPN

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