ABSTRACT

The use of vegetable fibers in the modern engineering industry represents a worldwide need for sustainable low-cost materials with desirable mechanical characteristics, such as high strength, modulus of elasticity and strain capacity. In order to be used as a reinforcement in composite systems, the Curauá fibers' durability and interface characteristics with the different matrices should be improved. The present work aims to characterize and compare the behavior of curauá filaments both in natural and treated conditions focusing on increasing their durability and bond performance. To minimize the degradation and high water absorption, two types of polymeric coatings were impregnated in the fibers: aluminum oxide and sand. Direct tensile tests were performed and correlated to the morphological observations of the fiber structure by SEM images. The adhesion between matrix and fiber was evaluated by pull-out tests. Volumetric changes due to the wetting and drying of the fibers were also analyzed. The results indicated an improvement of the fiber-matrix bond, fiber tensile strength and stiffness after the surface treatments. Additionally, the coating had a positive effect on the hydrophilic nature of the fiber, decreasing its water absorption capacity.

摘要

现代工程工业中植物纤维的使用代表了全球对具有理想机械特性（例如高强度、弹性模量和应变能力）的可持续低成本材料的需求。为了在复合材料系统中用作增强材料，Curauá 纤维的耐久性和与不同基体的界面特性应得到改善。目前的工作旨在描述和比较 curauá 长丝在自然和处理条件下的行为，重点是提高它们的耐用性和粘合性能。为了最大限度地减少降解和高吸水率，两种类型的聚合物涂层被浸渍在纤维中：氧化铝和沙子。进行直接拉伸试验，并将其与通过 SEM 图像对纤维结构的形态观察相关联。通过拔出试验评估基质和纤维之间的粘合力。还分析了由于纤维的润湿和干燥引起的体积变化。结果表明，表面处理后纤维与基体的结合力、纤维拉伸强度和刚度都有所提高。此外，涂层对纤维的亲水性有积极影响，降低了其吸水能力。