Characteristics of CNF-reinforced PA6 for PBF 3D Printers

抄録

Cellulose is the most abundant, renewable, and environmentally friendly bio-based polymer, which is available from non-edible biomass sources such as wood, grass, and agricultural residues. Cellulose is attracting much attention as a reinforcing material for resin that can replace glass fibers and glass beads. Composites of resin and cellulose nanofibers （CNFs） have been prepared for many attempts in the injection molding field, but only few tries in the 3D printing industry. Therefore, we have produced CNF-reinforced composites in demonstration facility, and verified the application of CNF-reinforced composites to powder bed fusion （PBF） 3D printers. In this research, we prepared a 5 wt% CNF compounded PA6 （CNF5%/PA6） powder by compounding of modified pulp fibers and PA6 pellets and followed by cryogenic powdering. The obtained CNF5%/PA6 powder was then molded to prepared test pieces by a PBF 3D printer, and the mechanical properties of the pieces were evaluated. As a result, the tensile strength and modulus of the CNF5%/PA6 test pieces were 60MPa and 2.6 GPa, and the bending strength and modulus were 95 MPa and 2.7 GPa, respectively. These values of the CNF5%/PA6 test pieces were similar to or better than mechanical properties of 20% glass bead-reinforced PA6 composites composite （GB20%/PA6）. Moreover, the CNF5%/PA6 3D model samples were almost 10% lighter than GB20%/PA6 because of characteristics of the lower density of CNFs than that of GB. Therefore, the CNF5%/PA6 powder is expected to be an important candidate as the raw material for the PBF type 3D printers.