The Effect of Hygroscopic Properties on the Hygromorph of Pla/Nanolignin Smart Biocomposite

Abstract

The field of Hygromorph BioComposites (HBC) is gaining traction due to their unique biological functionality resulting from the hygroscopic anisotropic properties of natural fiber ultrastructures. These properties, characterized by moisture-induced changes in stiffness, make them responsive to humidity variations. Although the use of HBC is a new development, there is still a lack of research on how they respond to changes in humidity levels. This study aims to fill this gap by investigating how the addition of nanolignin and epoxidized palm oil (EPO) as a plasticizer affects the hygroscopic properties of 3D-printed PLA/nanolignin biocomposites. The research also seeks to identify the optimal 3D printing layer height parameter that significantly impacts the hygroscopic characteristics of PLANanolignin biocomposites. Additionally, the study aims to determine the maximum water absorption capacity of the resulting PLA/Nanolignin smart biocomposites. These objectives were accomplished through the fabrication of PLA/Nanolignin filament using an extrusion process, followed by the production of 3D-printed biocomposites utilizing fused deposition modeling (FDM) techniques. Among the tested formulations, PLA supplemented with nanolignin (PLANL) exhibited the highest water absorption capacity at 7.39%, with a printing layer height of 0.6 mm. Scanning electron microscopy (SEM) was used to study the morphological features of the biocomposites. The results of this study provide new insights into the relationship between hygroscopic behavior and material composition, and they also offer guidance for the design and development of 3D-printed PLA/nanolignin biocomposites with improved hygroscopic properties.