Oak Ridge National Laboratory (ORNL) and Mitsubishi Chemical America have collaborated to develop a nearly 100% bio-based, biodegradable pelletized feedstock for large-format additive manufacturing (LFAM). Designed for large-scale 3D printing applications-such as construction tooling and single-use molds-this material offers a novel end-of-life solution for bio-based 3D-printed components.
While large-format 3D printing is increasingly used in construction and tooling, most current printing materials are petroleum-based polymers, which are difficult to recycle or dispose of in an environmentally friendly manner once the components reach the end of their service life. To address this challenge, the research team utilized poly(butylene succinate) (PBS)-a bio-based polyester commonly used in agriculture and packaging-as the primary matrix. By compounding it with polylactic acid (PLA) and wood flour (WF), they created a bio-composite pellet feedstock tailored for ORNL's large-scale, pellet-extrusion 3D printing systems (distinct from the filament-based materials used in desktop FDM printers).
As an agricultural and forestry-derived filler, wood flour improves printability, reduces raw material costs, and enhances material rigidity. However, high loading levels of wood flour typically compromise the tensile strength of composites, limiting their practical utility. In this study, the researchers incorporated a chain extender as a compatibilizing agent. This improved the interface between the PBS and PLA phases, as well as the bonding between the polymer matrix and the wood flour-even at wood flour loadings of up to 30 wt%. This approach effectively recovered the tensile mechanical properties lost due to the addition of the biomass filler, overcoming the strength limitations often associated with highly filled bio-composites.
The research team successfully validated the material through an engineering-grade prototype: they 3D-printed a mold for a precast concrete catch basin and poured 750 pounds of concrete into it. The mold withstood the load, demonstrating its practical potential for use as a single-use casting mold in construction applications. Aerobic biodegradation test results indicate that this composite material achieves a 40% biodegradation rate over 90 days-a performance that surpasses that of mainstream bio-based printing materials currently on the market. Once a component has reached the end of its service life, it can gradually biodegrade in aerobic environments such as compost or soil, eliminating the need for complex recycling processes. This makes the material particularly well-suited for short-term applications, including industrial tooling, temporary construction components, and landscape elements.
This work is detailed in a technical report published by Oak Ridge National Laboratory (ORNL). Authored by researchers including Cait Clarkson, Katie Copenhaver, Halil Tekinalp, and Soydan Ozcan, the report is available via the Office of Scientific and Technical Information (OSTI) public repository (accession number 3384917). The study also notes certain inherent limitations: the inclusion of wood flour as a filler leads to high water absorption, which can cause a decline in mechanical properties in humid environments. Furthermore, because biodegradation relies on aerobic composting conditions, the process takes significantly longer in typical outdoor settings. Consequently, the material is best suited for single-use or short-term components not subject to heavy, long-term loads, and it is not appropriate for use in permanent structural applications.
