Polymeric materials under harsh conditions undergo appreciable degradation, such as color change, lowering of mechanical strength, crack formation and deterioration. It has been established that these obvious changes are initiated by chain scissions owing to chemical reactions, such as oxidation and hydrolysis depending on the polymer skeletal structure. The subsequent degradation phenomena propagate through the architecture in a wide length scale from nanometers to micrometers. Accordingly, the time scale of degradation phenomena ranges from picosecond of the molecular motions to tens of years of aging of plastic molds such as gas pipes. In the present review, fundamentals of polymer degradation are described, and related topics are presented.
