Tran Hoang Thanh Tuyen, Baur Johannes, Radjef Racim, Nikzad Mostafa, Bjekovic Robert, Carosella Stefan, Middendorf Peter, Fox Bronwyn
Department of Mechanical Engineering and Product Design Engineering, Swinburne University of Technology, Melbourne 3122, Australia.
Institute of Aircraft Design, University of Stuttgart, 70569 Stuttgart, Germany.
Polymers (Basel). 2025 Jul 8;17(14):1891. doi: 10.3390/polym17141891.
This work presents the development of two vanillin-based vitrimer epoxy flax fibre-reinforced composites, with both the VER1-1-FFRC (a vitrimer-to-epoxy ratio of 1:1) and VER1-2-FFRC (a vitrimer-to-epoxy ratio of 1:2), via a vacuum-assisted resin infusion. The thermal and mechanical properties of the resulting vitrimer epoxy flax composites were characterised using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and mechanical four-point bending tests, alongside studies of solvent resistance and chemical recyclability. Both the VER1-1-FFRC (degradation temperature T of 377.0 °C) and VER1-2-FFRC (T of 395.9 °C) exhibited relatively high thermal stability, which is comparable to the reference ER-FFRC (T of 396.7 °C). The VER1-1-FFRC, VER1-2-FFRC, and ER-FFRC demonstrated glass transition temperatures T of 54.1 °C, 68.8 °C, and 83.4 °C, respectively. The low T of the vitrimer composite is due to the low crosslink density in the vitrimer epoxy resin. Particularly, the crosslinked density of the VER1-1-FFRC was measured to be 319.5 mol·m, which is lower than that obtained from the VER1-2-FFRC (434.7 mol·m) and ER-FFRC (442.9 mol·m). Furthermore, the mechanical properties of these composites are also affected by the low crosslink density. Indeed, the flexural strength of the VER1-1-FFRC was found to be 76.7 MPa, which was significantly lower than the VER1-2-FFRC (116.2 MPa) and the ER-FFRC (138.3 MPa). Despite their lower thermal and mechanical performance, these vitrimer composites offer promising recyclability and contribute to advancing sustainable composite materials.
本研究通过真空辅助树脂灌注法制备了两种基于香草醛的热固性弹性体环氧亚麻纤维增强复合材料，即VER1-1-FFRC（热固性弹性体与环氧树脂的比例为1:1）和VER1-2-FFRC（热固性弹性体与环氧树脂的比例为1:2）。通过热重分析（TGA）、差示扫描量热法（DSC）、动态力学分析（DMA）和机械四点弯曲试验，对所得热固性弹性体环氧亚麻复合材料的热性能和力学性能进行了表征，并研究了其耐溶剂性和化学可回收性。VER1-1-FFRC（降解温度T为377.0℃）和VER1-2-FFRC（T为395.9℃）均表现出较高的热稳定性，与参考ER-FFRC（T为396.7℃）相当。VER1-1-FFRC、VER1-2-FFRC和ER-FFRC的玻璃化转变温度T分别为54.1℃、68.8℃和83.4℃。热固性弹性体复合材料的低T是由于热固性弹性体环氧树脂中的交联密度较低。特别是，VER1-1-FFRC的交联密度经测量为319.5 mol·m，低于VER1-2-FFRC（434.7 mol·m）和ER-FFRC（442.9 mol·m）。此外，这些复合材料的力学性能也受到低交联密度的影响。事实上，VER1-1-FFRC的弯曲强度为76.7 MPa，明显低于VER1-2-FFRC（116.2 MPa）和ER-FFRC（138.3 MPa）。尽管这些热固性弹性体复合材料的热性能和力学性能较低，但它们具有良好的可回收性，有助于推动可持续复合材料的发展。
