Vitrimers have gained a great deal of attention from researchers, yet research on its application is still lacking. This study, a novel bio-based vitrimer was developed from epoxy (EP) and bio-based curing agents, that is, cashew nut shell liquid (CNSL) and citric acid (CA), and then reinforced by carbon fiber. The vitrimers with different ratios of acid to epoxy (R ratio) at 0.30–0.40 contained ester and ether linkages. All EP/CA/CNSL vitrimers showed the stress relaxation over 70–100°C due to transesterification. The vitrimers were applied as polymer matrices for the carbon fiber composites and then used as repair patches. By using the carbon fiber-reinforced vitrimer with the R ratio of 0.30, patch repair on a damaged alloy sheet revealed that approximately 98% of the tensile strength of the damaged alloy sheet was recovered. The vitrimer can be dissolved from carbon fiber composite to recover carbon fiber. The recovered carbon fiber retained good tensile strength compared to the pristine composite. Based on this study, the EP/CA/CNSL vitrimers showed the comparable thermomechanical properties with the epoxy vitrimer cured by the petroleum-based curing agent. The vitrimer composite patch could therefore be an alternative new repair method to extend the service life of damaged structures.

中文翻译：

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用生物基固化剂固化的碳纤维/环氧玻璃体复合补片用于一步修复金属板及其可回收性

玻璃体已经得到了研究人员的广泛关注，但对其应用的研究仍然缺乏。本研究采用环氧树脂（EP）和生物基固化剂，即腰果壳油（CNSL）和柠檬酸（CA）开发了一种新型生物基玻璃体，然后用碳纤维增强。具有 0.30-0.40 的不同酸与环氧基比（R 比）的玻璃体包含酯和醚键。由于酯交换作用，所有 EP/CA/CNSL 玻璃体在 70-100°C 时都表现出应力松弛。玻璃体被用作碳纤维复合材料的聚合物基质，然后用​​作修复补片。通过使用 R 比为 0.30 的碳纤维增强玻璃体，对受损合金板的修补修复表明，受损合金板的抗拉强度恢复了约 98%。玻璃体可以从碳纤维复合材料中溶解以回收碳纤维。与原始复合材料相比，回收的碳纤维保持了良好的拉伸强度。基于这项研究，EP/CA/CNSL 玻璃体显示出与由石油基固化剂固化的环氧玻璃体相当的热机械性能。因此，玻璃体复合贴片可能是一种替代的新修复方法，可延长受损结构的使用寿命。