Biodegradation

n The gradual breakdown of plastics and matter by living organisms such as bacteria, fungi, and yeasts. Most of the commonly used plastics are essentially not biodegradable, exhibiting limited susceptibility to assimilation by microorganisms. An exception is Polycaprolactam. However, the growing emphasis on environmental aspects of discarded plastics has stimulated research in ways of attaining biodegradability after a predetermined time period. One method is to add a UV-light sensitizer that causes photodegradation after a period of exposure to light, followed by breakup after prolonged exposure to the elements, after which bacteria will finish the job. A third method is the deliberate incorporation of weal links in the polymer chain, temporarily protected by a degradable stabilizer. (Zaiko GE (ed) (1995) Degradation and stabilization of polymers. Nova Science Publishers, Inc., New York) See also Photodegradation.