Investigation into hydroxypropyl-methylcellulose-reinforced polylactide composites for fused deposition modelling

Polylactide (PLA) is an aliphatic polyester biopolymer that can be derived from renewable agricultural products, such as corn, potatoes, rice, tapioca, and cane sugar. In this study, hydroxypropyl methylcellulose (HPMC)/PLA composite filaments with up to 7 % HPMC were prepared and used to produce parts via fused deposition modelling (FDM). The effect of the HPMC content on the microstructure, chemical structure, thermal properties, mechanical properties, and water contact angle (CA) was investigated. A uniform dispersion of HPMC within the PLA matrix was obtained. The incorporation of HPMC had no effect on the PLA chemical structure. Additionally, the cold crystallisation temperature decreased from 111 degrees C for the neat PLA filament to 104 degrees C for the composite filament with 7 % HPMC. The strengths of the composite filaments with 5 % and 7 % HPMC (51 MPa and 49 MPa, respectively) were maintained at a level comparable to that of their neat PLA counterpart (53 MPa). However, the tensile and impact strengths of the printed samples both decreased with the addition of HPMC, owing to the increased porosity. The hydrophilicity of the composites was significantly enhanced with the addition of HPMC, and the water contact angle of the sample with 7 % HPMC was reduced by approximately 30 degrees. This work represents a step towards a simple but promising way to prepare biocompatible HPMC/PLA composites for FDM.