Wang Baolong, Sun Xueying, Lu Fei, Shen Yibo, Xu Ningdi, Liu Yingying, Huang Yudong, Hu Zhen
School of Chemistry and Chemical Engineering, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, Harbin Institute of Technology, Harbin, 150001, China.
School of Chemistry and Chemical Engineering, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, Harbin Institute of Technology, Harbin, 150001, China.
Chemosphere. 2022 Nov;307(Pt 1):135780. doi: 10.1016/j.chemosphere.2022.135780. Epub 2022 Jul 20.
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 Fe catalyst in-situ forming strategy was exploited to nondestructively recycle carbon fiber (CF) from UPR composites via Fenton-like reaction. The nano-Fe catalyst employed in this strategy activated HO 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 Fe 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-Fe showed more efficient degradation ability than added nano-Fe or Fe 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 Fe catalytic degradation strategy may provide a promising practical application for nondestructively recycle CF from UPR composites.
热固性不饱和聚酯树脂（UPR）复合材料在工业上有广泛应用。然而，交联网络中大量稳定的碳 - 碳键使其难以降解，导致大量复合材料废弃物产生。在此，开发了一种纳米级铁催化剂原位形成策略，通过类芬顿反应从UPR复合材料中无损回收碳纤维（CF）。该策略中使用的纳米铁催化剂激活羟基自由基以去除UPR，具有温和的条件和高效的降解能力。为了使催化剂易于生长，通过碱性体系水解制备了多孔UPR。随后通过硼氢化物还原在水解树脂表面原位形成纳米级铁催化剂。得益于快速的传质过程，原位生长的纳米铁在类芬顿反应中比添加的纳米铁或铁催化剂表现出更高效的降解能力。实验表明，水解树脂在80℃下80分钟内可降解90%以上。通过气相色谱 - 质谱联用（GC - MS）、傅里叶变换红外光谱（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。特别是，观察到从复合材料中显著回收CF的过程，树脂被100%去除。回收的CF布保留了99%的强度，并保持了纺织结构、微观形貌和化学结构，实现了CF的无损回收。这种原位形成的纳米级铁催化降解策略可能为从UPR复合材料中无损回收CF提供一种有前景的实际应用方法。
