Synthesis, Recycling and High‐Throughput Reprocessing of Phase‐Separated Vitrimer‐Thermoplastic Blends

Abstract Phase‐separated polymer blends including a transesterification vitrimer and polypropylene are synthesized from widely available precursors through reactive processing. It is shown that proper formulation during the process including a viscosity modifier of the vitrimer precursors and a reactive interface compatibilizer yields well‐dispersed vitrimer phases with fractions up to 75 wt.% in the polypropylene phase. These vitrimer blends can be easily reprocessed by multiple shredding‐injection cycles and processed in high‐shear conditions through capillary rheometry. Rheological analyses reveal that a percolating dynamic network is formed across the vitrimer domains. It breaks apart during high shear reprocessing of the material and dynamically reforms after thermal annealing of the blends. It therefore ideally combines the mechanical and high‐throughput (re)processing properties of the thermoplastic matrix minor phase with the chemical, thermomechanical, and dynamic properties of the vitrimer major phase. This work illustrates the decoupling of processing at high shear rates enabled by the polypropylene processing aid from the kinetics of dynamic exchanges of the vitrimer phase and thermomechanical properties at the service temperature of the blends.