Natural fiber-reinforced composite (NFRC) filaments for 3D printing were fabricated using polylactic acid (PLA) reinforced with 1–5 wt% henequen flour comprising particles with sizes between 90–250 μm. The flour was obtained from natural henequen fibers. NFRCs and pristine PLA specimens were printed with a 0° raster angle for tension tests. The results showed that the NFRCs’ measured density, porosity, and degree of crystallinity increased with flour content. The tensile tests showed that the NFRC Young’s modulus was lower than that of the printed pristine PLA. For 1 wt% flour content, the NFRCs’ maximum stress and strain to failure were higher than those of the printed PLA, which was attributed to the henequen fibers acting as reinforcement and delaying crack growth. However, for 2 wt% and higher flour contents, the NFRCs’ maximum stress was lower than that of the printed PLA. Microscopic characterization after testing showed an increase in voids and defects, with the increase in flour content attributed to particle agglomeration. For 1 wt% flour content, the NFRCs were also printed with raster angles of ±45° and 90° for comparison; the highest tensile properties were obtained with a 0° raster angle. Finally, adding 3 wt% content of maleic anhydride to the NFRC with 1 wt% flour content slightly increased the maximum stress. The results presented herein warrant further research to fully understand the mechanical properties of printed NFRCs made of PLA reinforced with natural henequen fibers.
Novel intralayer hybrid composites (IHC) based on a commercial polylactic acid (PLA) matrix reinforced with a hybrid plain-woven fabric, composed of PLA filaments and sisal fibers, were obtained by film stacking followed by compression molding. Two different stacking configurations were explored. In one configuration, weft and warp directions of all fabric layers were equally oriented whereas in the other configuration, weft and warp directions of fabric layers were alternately oriented. The effect of the stacking sequence on the materials morphology and thermal and tensile behavior was investigated. All obtained composites presented higher thermal stability than the matrix due to the presence of the natural fibers and PLA filaments and also, the existence of lignocellulosic compounds in the woven fabric led to a char yield residue, with the expected improvement of flame retardant properties. Although both IHCs exhibited highly anisotropic tensile behavior, the composite having an alternated fabric layers configuration, presented a good balance of stiffness and strength for the two main orthogonal loading directions.