With few exceptions, it can be shown that the onset of oxidative degradation limits the useful lifetime of commodity thermoplastics. A considerable amount of chemical information has been generated concerning how to make such materials last longer by reducing the rate at which heat, radiation and mechanical stress cause the molecular weight reductions which give rise to the loss of useful properties. Combinations of stabilizing additives are universally used. In contrast, formulation have been developed which are characterized by enhanced sensitivity to sunlight; photodegradable plastics are produced commercially which last “indefinitely” indoors but which disintegrate in a few months outdoors. Commodity thermoplastics are largely very resistant to microorganisms and cannot be converted to “biodegradable” plastics bag admixture with anything.
