Tue 01, Jan 2019
Researchers have identified that combination of lignin with nylon delivers a composite that demonstrates increased room temperature stiffness and decreased melt viscosity.
Scientists from Oak Ridge National Laboratory (Oak Ridge, TN, US) have successfully developed a renewable 3D printing feedstock using lignin, which is a byproduct of biofuels.
Led by Amit Naskar, the team said to combine melt-stable hardwood lignin with conventional plastic, which is a low-melting nylon and carbon fiber. This resulted in developing a composite that possess the right attributes for extrusion and weld strength between layers during the printing process. It also offers good mechanical properties.
Typically, lignin has low heat resistance and can only be heated to a certain temperature for softening and extrusion from a 3D-printing nozzle. ORNL researchers discovered that pairing lignin with nylon increased the composite’s room temperature stiffness and decreased its melt viscosity. As per ORNL, the scientists successfully mixed a higher percentage of lignin - 40% to 50% by weight and then they added 4% to 16% carbon fiber.
The lignin-nylon composite is yet to be patented and the work is in progress to further refine the material and identify alternate ways to process it. The research was funded by DOE’s Office of Energy Efficiency and Renewable Energy’s Bioenergy Technologies Office.
The market for 3d-printed composites is on the rise and is likely to clock an annual revenue of US$ 111.1 in 2022, according to Stratview Research. Currently, most of the composite parts are fabricated through labor-intensive manufacturing processes, such as hand layup, which place this versatile material behind in the race compared with other competing materials in the mass-produced applications. Over the past two decades, composites industry has experienced a sheer transformation in the development of manufacturing process in terms of automation; however, end-use industries, such as automotive, are still demanding further reduction in the overall cycle time of finished parts. At the same time, they are also looking for such a process which curtails wastage during production. Here, 3D printing plays a vital role in delivering the customers’ expectation by making parts in lesser time with reduced wastage.