Fiber-reinforced thermosetting resin composites, especially carbon fiber reinforced epoxy resin composites and glass fiber reinforced unsaturated polyester resin composites, are widely used in aviation, aerospace, automotive, marine, circuit board, wind power and other fields. The recovery methods of thermosetting resin matrix composites mainly include mechanical recovery, heat recovery and chemical recovery, among which chemical recovery is the most promising recovery method. At present, chemical recovery mainly utilizes high-temperature or strong oxidants to non-selectively destroy the chemical structure of the resin matrix to obtain small-molecule degradation products and reinforcing fibers. The components of the degradation products are complex and difficult to recycle, and the fibers are seriously damaged.
The research team led by Hou Xianglin, a researcher at the Institute of Coal Chemistry of the Chinese Academy of Sciences, proposed a new approach for the selective degradation of bond-recovery thermoset resins, and used selective or weak coordination metal ions to selectively break the resin bond and achieve thermosetting properties. Resin-based composites for efficient degradation and full-component recovery. The use of unsaturated zinc ions in the aqueous phase system to selectively break the carbon-nitrogen bond of the epoxy resin enables efficient degradation and recycling of carbon fiber-reinforced epoxy resins (Green Chem., 2015, 17, 2141-2145). The use of weakly coordinated aluminum ion selective cleavage of ester bonds enables the degradation of glass fiber-reinforced unsaturated matrix resin (commonly known as FRP) (Green Chem., 2015, DOI: 10.1039/C5GC01048A). Relevant work At the same time, declare three national invention patents, one of which has been authorized (ZL 201310163799.1, 201410562107.5, 201510056492.0).
Because of its insoluble and infusible three-dimensional structure, thermosetting resins are very difficult to recycle. Economically, it is a research hotspot in the field of catalysis and environmental protection to open the solid CN bonds and CO bonds in thermosetting resins. The challenge of selective bond breaking lies in the selective activation of reactive sites. The coordination of unsaturated or weakly coordinated metal ions has a strong tendency to complex, easily interacts with heteroatoms in the resin, weakens the carbon heteroatom bond, and catalyzes Selective fracture. The study has little damage to recycled fibers, and the selective cleavage chemical bonds make the matrix degradation products unique in composition, which is beneficial for re-use; at the same time, the study selectively activates and breaks CN bonds or CO bonds by regulating the coordination state of metal ions. Important scientific value.
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