The Intrinsic Mechanochemical Reactivity of Vinyl‐Addition Polynorbornene

Herein we report the discovery of the intrinsic mechanochemical reactivity of vinyl‐addition polynorbornene (VA‐PNB), which has strained bicyclic ring repeat units along the polymer backbone. VA‐PNBs with three different side chains were found to undergo ring‐opening olefination upon sonication in dilute solutions. The sonicated polymers exhibited spectroscopic signatures consistent with conversion of the bicyclic norbornane repeat units into the ring‐open isomer typical of polynorbornene made by ring‐opening metathesis polymerization (ROMP‐PNB). Thermal analysis and evaluation of chain‐scission kinetics suggest that sonication of VA‐PNB results in chain segments containing a statistical mixture of vinyl‐added and ROMP‐type repeat units.