MECHANICAL PROPERTIES CHARACTERIZATIONS OF GREEN COMPOSITES MADE FROM POLY (LACTIC ACID) AND VARIOUS MILLED FIBERS WITH A MELT MIXING EXTRUDER FOR ADDITIVE MANUFACTURING APPLICATIONS
In the present study, as a preliminary report of the present authors on "On Additive Manufacturing of Green Composites" poly(lactic acid) PLA, composites, which is reinforced with two different kinds of reinforcing fibers in the form of milled filler, i.e. kenaf and carbon fibers, were molded by melt mixing and then filament extruding processes to make green composite filaments for 3D printing additive manufacturing purposes. From tensile test results of single monofilaments extruded from a FDM (Fused Deposition Modeling) 3D printer with a nozzle of 1mm diameter, it was found that the milled carbon fibers were able to reinforce PLA, while milled kenaf fibers and, for comparison purpose, cellulose base nano fillers were found to make little contribution for improvement in terms of strength and modulus of the present additive manufactured green composites. From the scanning electron microscope (SEM) fractography of the fracture surfaces in the present green composites, interface imperfections between PLA matrix and reinforcing fibers except carbon fibers, unevenness of reinforcing fiber distribution as well as existence of resin rich portions in the composites may have affected the present poor results obtained in this preliminary study.