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.

摘要

以商用聚乳酸 (PLA)为基体, 用PLA长丝和剑麻纤维组成的混杂平纹机织物增强, 通过薄膜叠层和模压成型制备了新型层内混杂复合材料 (IHC). 研究了两种不同的堆积结构. 在一种配置中, 所有织物层的纬纱和经纱方向是相等的, 而在另一种配置中, 织物层的纬纱和经纱方向是交替的. 研究了堆叠顺序对材料形貌, 热性能和拉伸性能的影响. 由于天然纤维和PLA长丝的存在, 所有获得的复合材料均表现出比基体更高的热稳定性, 并且, 机织物中木质纤维素化合物的存在导致残炭, 阻燃性能预期会得到改善. 尽管两种IHC均表现出高度各向异性的拉伸行为, 但具有交替织物层结构的复合材料在两个主要正交加载方向上表现出良好的刚度和强度平衡.

关键词:

• 混杂复合材料
• 堆叠顺序
• 层内混杂复合材料
• 聚乳酸
• 剑麻纤维
• 力学性能

KEYWORDS:

• Hybrid composites
• stacking sequence
• intralayer hybrid composites
• polylactic acid
• sisal fiber
• mechanical behavior