Researchers have made a bit of a breakthrough with sustainable 3D printer resins.
3D printer resins are quite useful, but also problematic due to their typical toxicity and non-sustainable sourcing. The researchers intended to reduce the effect of the latter.
They produced a more sustainable resin by preparing a 50-50 mix of bio-sourced materials and synthetic polyethylene glycol diacrylate (PEGDA). PEGDA is a common component of 3D printer resins that provides the photo-reactive effect, cross-linking agents, and mechanical flexibility. It’s also made from fossil sources — unsustainable. The two components were easily mixed in a single step to create a testable resin.
The bio-sourced components were derived from succinic acid (DAS), malic acid (DAM), and tartaric acid (DAT). The researchers tested a variety of combinations of these components and 3D printed results to understand whether they would perform as viable resins.
While they all exhibited proper polymerization, there were differences in the resulting parts.
The DAS:PEGDA formulation performed best in terms of thermal stability, printability, and mechanical robustness. Meanwhile, the DAM and DAT combinations were more brittle and thermally unstable, especially under post-curing heat.
DAS:PEGDA samples showed good resolution and minimal shrinkage during DLP printing, and had a glass transition temperature (Tg) around 34°C, with a modulus of ~127 MPa and tensile strength of ~5.8 MPa. The relatively low Tg is a bit concerning, as that is even lower than PLA. This could constrain possible applications of this material.
The researchers also found that the printed DAS:PEGDA parts would biodegrade a bit faster than standard resins: a ~16% weight loss in 90 days using lipase was observed. They believe the parts would completely decompose within five years, which is far better than most resin-printed parts.
While these materials are unlikely to catch on due to lower performance, this research does show that it is possible to integrate bio-sourced components into 3D printer resins. This will make the resins somewhat more sustainable, particularly in the decomposition phase.
It may be possible to develop variants of these resins with other additives — possibly also bio-sourced — that can alleviate some of the performance concerns.
