Purpose This study aims to investigate the effects of adding a minimal amount (0.5 Wt.%) of hexagonal boron nitride (hBN) nanoparticles to polylactic acid (PLA) and evaluate how two different dispersion methods, namely, dry mixing and ethanol-assisted physical blending, influence the mechanical, thermal, morphological and tribological properties of the resulting nanocomposites. Design/methodology/approach PLA/hBN nanocomposites were prepared via two physical mixing routes, extruded into filaments and three-dimensional printed using fused deposition modeling. Mechanical properties were assessed through tensile, Charpy impact and hardness tests. Tribological performance was evaluated via pin-on-disk friction tests. Thermal stability and chemical interactions were analyzed using thermogravimetric analysis, differential thermal analysis and Fourier-transform infrared spectroscopy (FTIR). Morphology and dimensional accuracy were examined using scanning electron microscopy and precision dimensional measurements. Findings The incorporation of only 0.5 Wt.% hBN significantly improved key properties of PLA. Tensile strength increased by up to 19.2% with dry mixing and 9.3% with ethanol-assisted mixing. Impact resistance showed remarkable enhancement, rising approximately fourfold for dry-mixed and 4.5-fold for ethanol-mixed composites. The coefficient of friction decreased by 33.8% and 35.3% for dry- and ethanol-mixed specimens, respectively. Thermal stability was maintained, and FTIR confirmed successful hBN integration with indications of interfacial interactions. Ethanol-assisted mixing promoted more homogeneous nanoparticle dispersion, leading to superior impact performance and more stable frictional behavior. Practical implications This work demonstrates that ultralow loadings of hBN can meaningfully enhance PLA’s performance, offering a viable and sustainable route to produce high-performance, biodegradable composites suitable for demanding applications in sectors such as aerospace, automotive and precision engineering, where a balance of strength, toughness and tribological performance is required. Originality/value While hBN reinforcement of polymers has been studied, research on ultralow filler concentrations (=0.5 Wt.%) and the direct comparison of simple, scalable dry- versus solvent-assisted physical mixing methods for PLA/hBN composites has been limited. This study provides new insights into how minimal filler content and dispersion methodology critically affect the multifunctional properties of biodegradable nanocomposites, presenting a practical framework for developing high-performance sustainable materials with minimal environmental and processing burden.
Sertkaya et al. (Wed,) studied this question.