Synergistic catalytic effect of triple dynamic bonds for fast-reprocessing and high-performance cross-linked polymers

Abstract

Dynamic cross-linked polymers (DCPs) are supposed to possess favourable reprocessability and degradability as well as excellent thermal and mechanical properties. However, achieving rapid reprocessing and high performance for DCPs is still a formidable challenge. Herein, a strategy of using a synergistic catalysis effect between different kinds of dynamic bonds (imine bonds, disulfide bonds and multiple hydrogen bonds) to accelerate dynamic exchange reactions was proposed and verified through small-molecule model reactions and DFT simulation computation, and it was applied to prepare high-performance and rapidly reprocessable DCPs. In addition, the viscosity of the DCPs decreased with rising shear rate by virtue of the dissociation of dynamic bonds in the network, which made this a promising material for preparing polyurethane composites through resin film infusion (RFI). Furthermore, the RFI process was simulated and confirmed by Moldex 3D. This work reveals the dynamic exchange accelerating mechanism for multiple dynamic systems and provides a strategy to produce DCPs combining high performance and fast reprocessability.