Trialkylsulfonium-Based Reprocessable Polyurethane Thermosets

Unprecedented associative exchange in CO2-sourced cyclic S,O-acetal-based covalent adaptable networks

“…disulfides, thioesters, or sulfonium salts). 24–31 While modifying the architectural features of CANs ( e.g. cross-link density, backbone stiffness and polarity) allows for fine-tuning their dynamic properties, 32 there remains a need to further explore new dynamic chemistry platforms.…”

Thermoreversible [2 + 2] Photodimers of Monothiomaleimides and Intrinsically Recyclable Covalent Networks Thereof

“…Covalent network materials, such as thermosets, are indispensable for their superior durability and thermomechanical robustness but also cause ever-increasing concerns because of their chemically unrecyclable nature . Considerable research efforts have focused on improving the sustainability of polymer networks by replacing the permanent 3D cross-linked network structure with reversible bond connectivity. , As a result, a plethora of covalent chemistry platforms have been developed to prepare dynamic polymer networks, thereby introducing material reshaping, healing, and reprocessing capabilities. − Predominantly thermal activation of the embedded dynamic cross-links has been harvested to induce covalent bond rearrangement and reshuffling of the network structure. A fundamental limitation using thermal equilibrium reactions, however, is the inability to exclusively trigger either the bond forming or bond breaking process in an orthogonal manner. , Hence, complete de-cross-linking and depolymerization back into the initial building blocks requires demanding reaction conditions (e.g., high temperatures) and/or additional chemicals (e.g., solvolysis) to shift the dynamic equilibrium toward the completely debonded state. , …”

Aliphatic C–H Insertion Strategies Enhancing Interactions among Waste Rubbers for Recycling

“…In the field of chemical biology, carbenes, known for linking small molecules to protein targets, show high reactivity with C–H bonds through C–H insertions. − Jürgen Rühe’s group has designed a series of diazo compounds (carbene precursors) which produce carbenes upon UV irradiation or heat, enabling polymer surface modification via carbene-mediated C–H insertions. − These optimally designed carbene precursors can be used to facilitate enhanced interactions among WR. Moreover, designing dynamic interactions is an effective approach to impart reprocessable properties to cross-linked polymers. − Our group anticipates that introducing dynamic interactions will grant reprocessability to recycled WR.…”