MOFs as New Catalytic Platform for Covalent Adaptable Networks: Catalysis Meets Reinforcement

Catalysis of bond exchange reactions is a versatile route to adjust kinetics and onset temperature of bond exchange reactions in covalent adaptable networks (CANs). In this work, we introduce a novel heterogeneous catalytic platform for CANs by immobilizing bases of low molecular weight on metal organic frameworks (MOFs). Specifically, the base 1,5,7-triazabicyclo(4.4.0)dec-5-ene (TBD) was coordinated on the MOF UiO-66. The obtained catalyst UiO-TBD benefits from the high loading capacity of the MOF and exhibits similar catalytic activity in accelerating thiol-thioester exchange reactions in dynamic photopolymers compared to free TBD while outperforming non-porous heterogeneous systems using ZrO₂ nanoparticles as a carrier. Moreover, it demonstrates a 37% higher thermal stability based on decreased volatility relative to free TBD. Beyond its catalytic role, UiO-TBD simultaneously reinforces the material, leading to enhanced mechanical performance and reduced creep. This approach offers broad applicability, driven by its modularity and scalability. UiO-TBD represents a two-in-one additive that not only catalyzes exchange reactions in CANs but also strengthens the network, opening new opportunities for multifunctional catalyst design in (dynamic) polymer systems.