Origin of critical molecular weight of amorphous polymer by mechanical degradation

Abstract

Polymer mechanochemistry is a burgeoning field as an alternative to solvent-based chemistry, thus regarded as green and energy-efficient approach to induce chemical reaction. Current study on polymer mechanochemistry mainly consists of mechanically induced degradation and polymerization. In both cases, existence of molecular weight limit (critical molecular weight) prohibits the degrading or synthesizing polymers in a mechanical manner. Although the importance to investigate the critical molecular weight for extending availability of polymer mechanochemistry, origin of the critical molecular weight still remains elusive. In this study, critical molecular weight of polymers are calculated based on a reptation model and suggests that entanglement plays a key role in mechanical degradation by hindering molecular diffusion of polymer chains.