Mechanically-induced chemical changes in polymeric materials

Mechanically-induced chemical changes in polymeric materials were studied. Polymeric materials exhibit an extraordinary range of mechanical responses, which depend on the chemical and physical structure of the polymer chains. The mechanical response of thermoplastic polymers is highly influenced by the molecular mass, chain entanglements, chain alignment, and degree of crystallinity. The mechanical properties of these amorphous polymers depend on the molecular mass and the cross-link density. The ability to predict the behavior and limitations of polymers in response to mechanical stress is important for determining their performance in a variety of applications. Quantum mechanical calculations and simulations have been used to predict the energy required to break bonds in small molecules and polymers and to predict which bonds are most likely to be cleaved. Mechanophores that undergo cross-linking reactions triggered by a mechanical field could provide a mechanism for modulating material properties in response to an external force field.