Impact of Stereocontrolled Polynorbornene Synthesis on Degradation Rate

We synthesized a family of polynorbornenes with a wide range of <i>cis</i>/<i>trans</i> compositions by ring-opening metathesis polymerization (ROMP) with a variety of ruthenium catalysts and subjected these materials to ultrasonication as a proxy for mechanical degradation. Increasing the <i>cis</i>-alkene content enhanced the degradation rate for both short (∼70 kDa) and long (∼700 kDa) polynorbornenes. These data suggest that the heightened allylic strain in <i>cis</i>- versus <i>trans</i>-polynorbornene promotes faster degradation independent of molecular weight under mechanical stress. Our results complement existing plastics recycling research by isolating the understudied relationship between backbone stereochemistry and degradability.