Plastic when exposed to UV sunlight; plastics can undergo a process called photodegradation.
Photodegradation is a chemical reaction that breaks down the polymer chains that make up the plastic.
Plastic absorbs the UV radiation, which excites the electrons in the polymer chains, the excited electrons break chemical bonds, creating highly reactive molecules called free radicals. Free radicals attack the polymer chains, causing them to break down into smaller fragments As the polymer chains are degraded, the plastic becomes weaker, brittle, starts to crack and flake.
Plastics that are particularly susceptible to photodegradation:
Polypropylene (PP): Often used for outdoor furniture and containers.
Polyethylene (PE): Used in plastic bags, bottles, and pipes.
Polystyrene (PS): Used in foam cups, packaging materials, and toys.
