Morphological, Mechanical and Thermal Characterization of Intralayer Hybrid Composites Based on Polylactic Acid (PLA) and Sisal Fiber

Abstract

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.