Making PNB from…PNB? Yep.

Congrats to Daniel Lee and Tori Kensy! Their work, in collaboration with Prof. Brian Long and Christopher Maroon (each at UT-Knoxville), was just accepted for publication in Angewandte Chemie. This paper describes the mechanochemical conversion …

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 to 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.