Researchers from Freiburg University used a DIW 3D printing technique (pictured) to test their novel environmentally-friendly wood-based 3D printing material. Image via Lisa Ebers, Freiburg University.
Economically upgrading lignin
What sets the UD research apart from others in the area is its focus on the economics of the upscaling process. One of the main drawbacks of upgrading lignin is that many existing processes operate at very high temperatures, and are therefore expensive and difficult to scale. Current industrial techniques also still come with the safety concerns, capital costs, and energy consumption associated with traditional solvents, temperatures, or pressures.
To address these challenges, the UD research team replaced methanol, a traditional solvent used in lignin deconstruction, with glycerin to enable the process to take place at a normal atmospheric pressure. Glycerin is an inexpensive ingredient typically used in liquid cosmetics, soaps and shampoos for its moisturizing benefits, but can also be used to break down lignin into its chemical building blocks, from which a broad range of bio-based products like 3D printing resins can be made.
Replacing methanol with glycerin provided the same chemical functionality but at a much lower vapor pressure, eliminating the need for a closed system. This enabled the researchers to complete the process’ reaction and separation steps simultaneously, leading to a more cost-effective system.
According to the researchers, operating at atmospheric pressure is not only safer, but also provides a straightforward route to scale the method up from small batches to run continuously, which they say will create more material cheaper, faster, and with less manual labor.