Savicheva Sofya, Rapp Bastian E, Teuscher Nico
Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg im Breisgau, Germany.
Fraunhofer Institute for Microstructure of Materials and Systems IMWS, 06120 Halle (Saale), Germany.
Materials (Basel). 2024 Aug 28;17(17):4244. doi: 10.3390/ma17174244.
Fiber-reinforced composites (FRCs) represent a promising class of engineering materials due to their mechanical performance. However, the vast majority of FRCs are currently manufactured using carbon and glass fibers, which raises concerns because of the difficulties in recycling and the reliance on finite fossil resources. On the other hand, the use of natural fibers is still hampered due to the problems such as, e.g., differences in polarity between the reinforcement and the polymer matrix components, leading to a significant decrease in composite durability. In this work, we present a natural fiber-reinforced composite (NFRC), incorporating plasma pre-treated flax fibers as the reinforcing element, thermoplastic polylactic acid (PLA) as a matrix, and a key point of the current study-a thermoset coating based on epoxidized linseed oil for adhesion improvement. Using atmospheric plasma-jet treatment allows for increasing the fiber's surface energy from 20 to 40 mN/m. Furthermore, a thermoset coating layer based on epoxidized linseed oil, in conjunction with dodecyl succinic anhydride (DDSA) as a curing agent and 2,4,6-tris(dimethyl amino methyl) phenol (DMP-30) as a catalyst, has been developed. This coated layer exhibits a decomposition temperature of 350 °C, and there is a substantial increase in the dispersive surface-energy part of the coated flax fibers from 8 to 30 mN/m. The obtained natural fiber-reinforced composite (NFRC) was prepared by belt-pressing with a PLA film, and its mechanical properties were evaluated by tensile testing. The results showed an elastic modulus up to 18.3 GPa, which is relevant in terms of mechanical properties and opens up a new pathway to use natural-based fiber-reinforced bio-based materials as a convenient approach to greener FRCs.
纤维增强复合材料（FRCs）因其机械性能而成为一类很有前景的工程材料。然而，目前绝大多数FRCs是使用碳纤维和玻璃纤维制造的，由于回收困难以及对有限化石资源的依赖，这引发了人们的担忧。另一方面，天然纤维的使用仍然受到阻碍，原因是存在诸如增强材料与聚合物基体组分之间极性差异等问题，导致复合材料耐久性显著下降。在这项工作中，我们展示了一种天然纤维增强复合材料（NFRC），它包含经等离子体预处理的亚麻纤维作为增强元素、热塑性聚乳酸（PLA）作为基体，以及当前研究的一个关键点——基于环氧化亚麻籽油的热固性涂层以改善附着力。使用常压等离子体射流处理可使纤维的表面能从20毫牛顿/米增加到40毫牛顿/米。此外，还开发了一种基于环氧化亚麻籽油的热固性涂层，它与作为固化剂的十二烷基琥珀酸酐（DDSA）以及作为催化剂的2,4,6 - 三（二甲氨基甲基）苯酚（DMP - 30）一起使用。该涂层的分解温度为350℃，涂覆亚麻纤维的分散表面能部分从8毫牛顿/米大幅增加到30毫牛顿/米。所制备的天然纤维增强复合材料（NFRC）通过与PLA膜进行带式压制而成，其机械性能通过拉伸试验进行评估。结果表明弹性模量高达18.3吉帕斯卡，就机械性能而言这具有重要意义，并为使用天然基纤维增强生物基材料作为制造更环保FRCs的便捷方法开辟了一条新途径。
