Abstract：
Thermosetting unsaturated polyester resin (UPR) composites were found widespread industrial applications. However, the numerous stable carbon-carbon bonds in cross-linked networks made them intractable for degradation, causing the large-scale composite wastes. Here a nanoscale Fe0 catalyst in-situ forming strategy was exploited to nondestructively recycle carbon fiber (CF) from UPR composites via Fenton-like reaction. The nano-Fe0 catalyst employed in this strategy activated H2O2 for removing UPR, featuring mild conditions and efficient degradation ability. Aiming at facile growth of the catalyst, a porous UPR was achieved by the hydrolysis of alkalic system. The nanoscale Fe0 catalyst was subsequently formed in-situ on the surface of hydrolyzed resin by borohydride reduction. Benefiting from fast mass transfer, the in-situ grown nano-Fe0 showed more efficient degradation ability than added nano-Fe0 or Fe2+ catalyst during Fenton-like reaction. The experiments indicated that hydrolyzed resin could be degraded more than 90% within 80 min, 80 °C. GC-MS, FT-IR analysis and Density functional theory (DFT) calculation were conducted to explained the fracture processes of carbon skeleton in hydrolyzed resin. Especially, a remarkable recovery process of CF from composites was observed, with a 100 percent elimination of resin. The recycled CF cloth exhibited a 99% strength retention and maintained the textile structure, microtopography, chemical structure, resulting in the nondestructive reclaim of CF. This in-situ formed nanoscale Fe0 catalytic degradation strategy may provide a promising practical application for nondestructively recycle CF from UPR composites.
摘要：
热固性不饱和聚酯树脂（UPR）复合材料被发现广泛的工业应用。然而,交联网络中众多稳定的碳-碳键使它们难以降解，造成大规模的复合废物。在这里，利用纳米级Fe0催化剂原位形成策略，通过类Fenton反应从UPR复合材料中无损回收碳纤维（CF）。该策略中使用的纳米Fe0催化剂活化H2O2以去除UPR，具有温和的条件和高效的降解能力。针对催化剂的容易生长，通过碱体系的水解实现了多孔UPR。随后通过硼氢化物还原在水解树脂的表面上原位形成纳米级Fe0催化剂。受益于快速传质，在类Fenton反应过程中，原位生长的纳米Fe0比添加的纳米Fe0或Fe2催化剂显示出更有效的降解能力。实验表明，水解树脂可以在80min内降解90%以上，80°CGC-MS,通过FT-IR分析和密度泛函理论(DFT)计算来解释水解树脂中碳骨架的断裂过程。尤其是,从复合材料中观察到CF的显着恢复过程，100%消除树脂。回收的CF布表现出99％的强度保留和保持纺织结构，微观形貌,化学结构,导致CF的无损回收。这种原位形成的纳米级Fe0催化降解策略可以为从UPR复合材料中无损回收CF提供有前途的实际应用。
