Thermoset polymers with permanently cross-linked networks have outstanding mechanical properties and solvent resistance, but they cannot be reprocessed or recycled. On the other hand, vitrimers with covalent adaptable networks can be recycled. Here we provide a simple and practical method coined as "vitrimerization" to convert the permanent cross-linked thermosets into vitrimer polymers without depolymerization. The vitrimerized thermosets exhibit comparable mechanical properties and solvent resistance with the original ones. This method allows recycling and reusing the unrecyclable thermoset polymers with minimum loss in mechanical properties and enables closed-loop recycling of thermosets with the least environmental impact.
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http://dx.doi.org/10.1021/acsmacrolett.0c00299 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, 800 Dongchuan Road, 200240, Shanghai, CHINA.
Covalent adaptable networks (CANs), a novel class of crosslinked polymers with dynamic covalent bonds, have gained significant attention for combining the durability of thermosets with the reprocessability of thermoplastics, making them promising for emerging applications. Here, we report the first example of poly[2]rotaxane-type CANs (PRCANs), in which oligo[2]rotaxane backbones characterized by densely packed mechanical bonds, are cross-linked through dynamic C-N bond. Oligo[2]rotaxane backbones could guarantee the mechanical properties of CANs.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
Department of Advanced Materials Engineering, Chung-Ang University, Anseong, 17546, Republic of Korea.
Transport equipment manufacturers in the automotive and aerospace industries are focused on developing materials that enhance fuel efficiency and reduce carbon dioxide emissions. A significant approach is employing lightweight materials like aluminum, magnesium, and polymer-based composites. Polyamide-based composites, particularly nylon 66, as viable alternatives due to their excellent rigidity, chemical resistance, and thermal stability are investigated to address the limitations of traditional thermosetting resins, which are difficult to recycle and have lengthy molding processes that hinder mass production.
View Article and Find Full Text PDFChemSusChem
January 2025
Qingdao University, College of Chemistry and Chemical Engineering, 308 Ningxia Road, Qingdao, CHINA.
Polyurethane (PU), as a thermoset polymer, is extensively utilized in various applications, such as refrigerator foams, sponges, elastomers, shoes, etc. However, the recycling of post-consumed PU poses significant challenges due to its intricate and extensive crosslinking structures. Catalytic hydrogenation is one of the most effective methods for recycling PU waste, nevertheless, there is currently a lack for a hydrogenation catalyst that is both high-performing, recyclable, and cost-effective for breaking down post-consumed PU materials.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Materials Science and Engineering, Norwegian University of Science and Technology, NTNU, Sem Sælands vei 12, 7034 Trondheim, Norway.
In thermosetting epoxies, thermomechanical properties can be enhanced by conscious selection of curing agents. Full cross-linking leads to a maximum in the glass- transition temperature. However, the relation between the glass transition temperature and the epoxy matrix depends on several factors beyond the cross-linking degree, such as the molecular weight of the polymers, network organization, amount of branching, and the presence of hydrogen bonds.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States.
Highly energetic boron (B) particles embedded in hydroxyl-terminated polybutadiene (HTPB) thermosetting polymers represent stable solid-state fuel. Laser-heating of levitated B/HTPB and pure HTPB particles in a controlled atmosphere revealed spontaneous ignition of B/HTPB in air, allowing for examination of the exclusive roles of boron. These ignition events are probed via simultaneous spectroscopic diagnostics: Raman and infrared spectroscopy, temporally resolved high-speed optical and infrared cameras, and ultraviolet-visible (UV-vis) spectroscopy.
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