<![CDATA[The development of biomaterial-based filaments has become a strategic approach to promoting sustainability in additive manufacturing technologies. This study aims to analyze the crystalline structure and phase behavior of polylactic acid (PLA)-based biocomposite filaments reinforced with Oil Palm Empty Fruit Bunch (OPEFB) cellulose as an environmentally friendly filler for fused deposition modeling (FDM) applications. The biocomposite filaments were fabricated via an extrusion process using PLA as the polymer matrix and OPEFB cellulose in the form of microfibrillated cellulose, with composition variations of 0, 2, 10, and 30 wt.%. Extrusion was conducted at a processing temperature of 135 °C and a screw speed of 840, under controlled conditions to ensure stable filament formation and uniform diameter. The crystalline structure and phase characteristics of the filaments were characterized using X-ray Diffraction (XRD). The XRD results reveal that all filament compositions retain the primary crystalline phase of PLA, indicating that the incorporation of OPEFB cellulose does not alter the fundamental crystal structure of the polymer matrix. However, increasing OPEFB content leads to a reduction in diffraction peak intensity and a corresponding increase in the amorphous phase contribution, indicating a decrease in the degree of crystallinity of PLA. This reduction becomes more pronounced at OPEFB contents of 10 wt.% and 30 wt.% due to restricted molecular chain mobility caused by the presence of cellulose as a reinforcing filler. Overall, the findings demonstrate that OPEFB cellulose influences the crystalline structure of PLA filaments in a progressive manner without inducing the formation of new crystalline phases. Filaments with low to moderate OPEFB contents exhibit the most favorable balance between crystalline and amorphous structures, highlighting their potential as sustainable filament materials for 3D printing applications]]>
