This talk will report that the radical cage effect is the underlying phenomenon responsible for controlling the rates of polymer photochemical degradation reactions. In particular, the radical cage effect controls how and explains why the rates of polymer photodegradation are dependent on the molecular weight of the polymer, the temperature, the morphology of the polymer, the intensity and wavelength of the light, and on the stresses on the polymer sample. The efficiency of radical cage escape from the radical cage pair (see the figure) is the determining factor in controlling the rate of polymer degradation. In turn, the efficiency of cage escape is determined by the local environment around the radicals produced by photolysis. To facilitate our mechanistic studies of polymer photodegradation, we synthesize and study polymers with metal-metal bonds along their backbones. These polymers are photochemically reactive, and the relative straightforwardness of their degradation reactions allowed us to probe in great detail how the local environment around the polymer radicals impacts the degradation rates. The implications of these results for the degradation of commodity polymers and plastics will be discussed.

Importance of radical cage effects in the photochemical degradation of polymers

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.