Rodricks Carol Winnifred, Greenfeld Israel, Fiedler Bodo, Wagner Hanoch Daniel
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 7610001, Israel.
Institute of Polymers and Composites, Hamburg University of Technology, D-21073 Hamburg, Germany.
Materials (Basel). 2022 Jan 24;15(3):890. doi: 10.3390/ma15030890.
The fibre-matrix interface plays an important role in the overall mechanical behaviour of a fibre-reinforced composite, but the classical approach to improving the interface through chemical sizing is bounded by the materials' properties. By contrast, structural and/or geometrical modification of the interface may provide mechanical interlocking and have wider possibilities and benefits. Here we investigate the introduction of polymer beads along the interface of a fibre and validate their contribution by a single fibre fragmentation test. Using glass fibres and the same epoxy system for both matrix and beads, an increase of 17.5% is observed in the interfacial shear strength of the beaded fibres compared to fibres with no polymer beads. This increase should lead to a similar improvement in the strength and toughness of a beaded fibre composite when short fibres are used. The beads were also seen to stabilise the fragmentation process of a fibre by reducing the scatter in fragment density at a given strain. A case could also be made for a critical beads number-4 beads in our experimental system-to describe interfacial shear strength, analogous to a critical length used in fibre composites.
纤维-基体界面在纤维增强复合材料的整体力学行为中起着重要作用，但通过化学上浆改善界面的传统方法受材料性能的限制。相比之下，界面的结构和/或几何改性可提供机械联锁，具有更广泛的可能性和益处。在此，我们研究了沿纤维界面引入聚合物珠粒，并通过单纤维断裂试验验证其作用。使用玻璃纤维以及用于基体和珠粒的相同环氧树脂体系，与没有聚合物珠粒的纤维相比，带珠粒纤维的界面剪切强度提高了17.5%。当使用短纤维时，这种提高应会使带珠粒纤维复合材料的强度和韧性得到类似的改善。还观察到珠粒通过降低给定应变下碎片密度的离散度来稳定纤维的断裂过程。在我们的实验体系中，也可以提出一个临界珠粒数——4个珠粒——来描述界面剪切强度，这类似于纤维复合材料中使用的临界长度。
