Valášek Petr, Müller Miroslav, Šleger Vladimír, Kolář Viktor, Hromasová Monika, D'Amato Roberto, Ruggiero Alessandro
Department of Material Science and Manufacturing Technology, Faculty of Engineering, Czech University of Life Sciences Prague, Kamycka 129, 6-Suchdol, 165 00 Prague, Czech Republic.
Department of Mechanical Engineering, Faculty of Engineering, Czech University of Life Sciences Prague, Kamycka 129, 6-Suchdol, 165 00 Prague, Czech Republic.
Materials (Basel). 2021 May 18;14(10):2636. doi: 10.3390/ma14102636.
Composite materials with natural fillers have been increasingly used as an alternative to synthetically produced materials. This trend is visible from a representation of polymeric composites with natural cellulose fibers in the automotive industry of the European Union. This trend is entirely logical, owing to a preference for renewable resources. The experimental program itself follows pronounced hypotheses and focuses on a description of the mechanical properties of untreated and alkali-treated natural vegetable fibers, coconut and abaca fibers. These fibers have great potential for use in composite materials. The results and discussion sections contribute to an introduction of an individual methodology for mechanical property assessment of cellulose fibers, and allows for a clear definition of an optimal process of alkalization dependent on the content of hemicellulose and lignin in vegetable fibers. The aim of this research was to investigate the influence of alkali treatment on the surface microstructure and tensile properties of coir and abaca fibers. These fibers were immersed into a 5% solution of NaOH at laboratory temperature for a time interval of 30 min, 1 h, 2 h, 3 h, 6 h, 12 h, 24 h, and 48 h, rinsed and dried. The fiber surface microstructures before and after the alkali treatment were evaluated by SEM (scanning electron microscopy). SEM analysis showed that the alkali treatment in the NaOH solution led to a gradual connective material removal from the fiber surface. The effect of the alkali is evident from the visible changes on the surface of the fibers.
含有天然填料的复合材料已越来越多地被用作合成材料的替代品。从欧盟汽车行业中含天然纤维素纤维的聚合物复合材料的情况就能看出这一趋势。由于对可再生资源的偏好，这一趋势完全合乎逻辑。实验项目本身遵循明确的假设，并专注于描述未经处理和经碱处理的天然植物纤维（椰子纤维和马尼拉麻纤维）的机械性能。这些纤维在复合材料中具有很大的应用潜力。结果与讨论部分有助于引入一种用于纤维素纤维机械性能评估的独特方法，并能根据植物纤维中半纤维素和木质素的含量清晰定义最佳碱化工艺。本研究的目的是调查碱处理对椰壳纤维和马尼拉麻纤维的表面微观结构和拉伸性能的影响。将这些纤维在实验室温度下浸入5%的氢氧化钠溶液中，浸泡时间分别为30分钟、1小时、2小时、3小时、6小时、12小时、24小时和48小时，然后冲洗并干燥。通过扫描电子显微镜（SEM）评估碱处理前后纤维的表面微观结构。扫描电子显微镜分析表明，在氢氧化钠溶液中的碱处理导致纤维表面的连接材料逐渐去除。从纤维表面明显的变化可以看出碱的作用。
