Study on properties of polylactic acid/lemongrass fiber biocomposites prepared by fused deposition modeling

In this paper, poly(lactic acid) grafted with maleic anhydride (PLA-g-MAH) was prepared by melt grafting, and added into poly(lactic acid)/lemongrass fiber (PLA/LF) biocomposites after analyzing the chemical properties of LF. The effect of PLA-g-MAH on the properties of PLA/LF biocomposites was studied. Differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), scanning electron microscope (SEM) were used to characterize the crystallinity, isothermal crystallization behavior, thermal stability and microstructure of the biocomposites. In addition, the mechanical properties of biocomposites prepared by fused deposition modeling (FDM) 3D printing technology were also characterized. The results show that, the contents of cellulose, hemicellulose and lignin are 22.5%, 36.4%, and 22.8%, respectively in the composition of LF. With the addition of LF, the flexural modulus, crystallinity and crystallization rate of biocomposites are improved. After PLA-g-MAH was added, the crystallization rate of PLA is further slightly increased, but the crystallinity is not changed much. The mechanical properties of the PLA/LF biocomposites are improved to the greatest extent when 5 wt% PLA-g-MAH was added. PLA-g-MAH can significantly reduce the internal cavity and fiber peeling phenomenon, and there is no obvious gap between phases so that interface compatibility of PLA and LF is improved obviously.