Polylactide/hemp hurd biocomposites as sustainable 3D printing feedstock

Industrial hemp hurd (HH) is emerging as a bio-based filler in thermoplastic biocomposites. In this paper, HH/polylactide (PLA) biocomposites were developed as fused deposition modelling (FDM) feedstock through parametric analysis of the effects of HH loading with respect to melt flow, rheology, physical, thermo-mechanical, and mechanical properties of the biocomposites. Poly (butylene adipate-co-terephthalate) (PBAT) and ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EGMA) were used as toughening and compatibilisation agents respectively in melt-compounding and extrusion to produce FDM filament. The FDM-printed standard samples were compared against corresponding injection-moulded biocomposites. The FDM filament exhibited a diameter tolerance within +/- 0.02 mm, and roundness variability below 0.03 mm, and the FDM-printed parts with HH loading under 30 phr showed higher impact toughness than the commercial PLA filament control. In addition, the FDM-printed samples exhibited greater dimensional accuracy with increasing HH loading.