Aramid fiber reinforced composites (AFRCs) have received increasing attention because of their excellent comprehensive performance including high mechanical strength, high modulus, and light weight. However, full recycling of AFs from ARCFs is difficult to achieve. Herein, fully recyclable ARCFs are fabricated using reversible cross-linked polyurea plastics (PUHA) as the matrix. PUHA plastics are fabricated by cross-linking linear polyurea using hemiaminal groups. By changing the main chain structures, two types of PUHA plastics are prepared with excellent mechanical performance, which is comparable to that of traditional engineering plastics. PUHA plastics can be reprocessed at least five times without losing their original mechanical properties because of the dynamic exchangeability of the hemiaminal groups. Meanwhile, PUHA plastics can be rapidly depolymerized into linear polyurea under acidic conditions. When PUHA plastics are used as a matrix to fabricate AFRCs, the AFRCs exhibit excellent mechanical strength. Moreover, due to the simple chemical recycling ability of PUHA plastics, AFRCs can be fully decomposed into intact AFs and linear polyurea with high purity. This work presents the use of reversible cross-linked polyurea plastics in the fabrication of fully recyclable AFRCs and provides the future direction of developing fully recyclable and high-performance fiber-reinforced composites.

中文翻译：

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化学可回收、可再加工且机械强度高的可逆交联聚脲塑料，用于完全可回收的芳纶纤维增强复合材料


芳纶纤维增强复合材料 （AFRCs） 因其高机械强度、高模量和重量轻等优异的综合性能而受到越来越多的关注。但是，很难实现 ARCF 中 AF 的完全回收。在此，使用可逆交联聚脲塑料 （PUHA） 作为基体制造完全可回收的 ARCF。PUHA 塑料是通过使用半氨基交联线性聚脲制成的。通过改变主链结构，制备出两种类型的PUHA塑料，具有优异的机械性能，与传统工程塑料相当。由于半氨基的动态交换性，PUHA 塑料可以进行至少五次再加工而不会失去其原始的机械性能。同时，PUHA 塑料可以在酸性条件下快速解聚成线性聚脲。当 PUHA 塑料用作制造 AFRC 的基体时，AFRC 表现出优异的机械强度。此外，由于 PUHA 塑料的简单化学回收能力，AFRC 可以完全分解成完整的 AF 和高纯度的线性聚脲。这项工作介绍了可逆交联聚脲塑料在制造完全可回收的 AFRC 中的应用，并为开发完全可回收和高性能纤维增强复合材料提供了未来方向。