Photodegradable plastics are synthetic polymers with light-sensitive chemical additives or copolymers that weaken the bonds of the polymer in the presence of ultraviolet radiation.
These plastics are designed to become weak and brittle upon prolonged exposure to sunlight. Biodegradation occurs only after an initial photodegradation stage in which UV light triggers degradation of the polymer. UV sensitizers in the polymer assist this process.
Initially, the polymer is converted into low-molecular-weight materials, such as waxes, and then further broken down into carbon dioxide and water by bacterial action.