A Comparative Life Cycle Assessment of Hemp-based and Polylactide (PLA) Composite 3D Printing Filaments

There is a growing interest in exploring the potential use of bio-based 3D printing filaments as sustainable substitutes for traditional polymer-based filaments. This study analyzes the environmental impacts of hemp materials (hemp straw, hemp hurd, and hemp fiber) when blended with pure PLA (Polylactic Acid) for 3D printing filaments. A comparative Life Cycle Assessment (LCA) was conducted using the ReCiPe 2016 method to evaluate midpoint and endpoint impact categories, along with two single-issue methods, Cumulative Energy Demand (CED) and IPCC Global Warming Potential (GWP100), to assess energy and carbon-related impacts of such filaments. The results indicate that hemp straw PLA filament has the lowest environmental impacts, followed by hemp hurd PLA, hemp fiber PLA, and pure PLA, with the last exhibiting the highest overall impacts in all endpoint categories (human health, ecosystems, and resources) using the ReCiPe 2016 method. Moreover, pure PLA demonstrates the highest global warming potential (GWP) across all filaments, while hemp fiber PLA displays higher impacts in energy consumption due to its higher density. Sensitivity analyses exploring the effects of varying the PLA blend ratio on environmental outcomes reveal that increased PLA content raises energy demand and carbon emissions across all filaments. Hemp-based PLA filaments, particularly hemp straw and hurd, hold promise as sustainable alternatives to pure PLA, especially for applications not requiring high-performance mechanical properties. Future research will focus on evaluating the use of treated biomass in filament production, specifically emphasizing hemp straw to enhance the sustainability performance of 3D printing filament materials.