Recyclable and malleable thermosets enabled by activating dormant dynamic linkages

Reconfigurable, Solvent-Processable, NIR-Triggerable Shape Memory Cyanate Esters for Smart Molds

“…Therefore, the SMCE with DCB is expected to solve the problem of cyanate ester as a smart mold (preparation of complex structures achieved). Recently, alkyl-polycyanurate thermosets were reported to exhibit closed-loop recyclability and reprocessing capability through the activation of dormant dynamic linkages . In our work, the stress relaxation of CESC at the temperature range (180–260 °C) was investigated, as shown in Figure a; the stress relaxation curves of CESC3 confirm the presence of high-temperature DCB.…”

“…Recently, alkylpolycyanurate thermosets were reported to exhibit closed-loop recyclability and reprocessing capability through the activation of dormant dynamic linkages. 27 In our work, the stress relaxation of CESC at the temperature range (180−260 °C) was investigated, as shown in Figure 3a; the stress relaxation curves of CESC3 confirm the presence of high-temperature DCB. Concerning the pseudo-first-order reaction of DCB, the kinetics of the reaction was fitted by the Arrhenius plot, as shown in Figure 3b, and the activation energy of DCB is 128.63 kJ/mol.…”

Recent development of end-of-life strategies for plastic in industry and academia: bridging their gap for future deployment

“…14A), which exhibit strong mechanical properties with varying ductility based on the structure of monomer used. 40 The polycyanurates can also be depolymerized to reform the triazine monomer by refluxing in ethanol, and the depolymerization can be accelerated with the addition of K 2 CO 3 . The recovered monomers can be used to repolymerize materials of similar properties as the original virgin polymer (Fig.…”

Chemical Recycling of Thiol Epoxy Thermosets via Light-Driven C–C Bond Cleavage

“…Different strategies have been developed to address the recyclability of thermosets. ,− Conventional pyrolysis can degrade thermosets into lower molecular weight products under high temperatures, but such processes are energy-intensive and afford product mixtures that would require purification prior to use. − Milder chemical methods have also been developed, which rely almost exclusively on the hydrolysis of polymers carrying acid- or base-labile functional groups (Figure A). − While effective, this approach cannot be applied to materials that are not susceptible to hydrolysis, such as epoxies, which are among the most widely produced thermosets. − Alternatively, new thermosets with enhanced degradability have been developed by the inclusion of stimuli-triggered cleavable functional groups or dynamic covalent bonds within the network. − Although these materials show promise at the laboratory scale, they have yet to be broadly adopted for commercial applications. Thus, there remains a need to develop efficient recycling technologies for existing commercial thermosets, which are extremely limited compared with those for thermoplastics. − …”