Polyethylene terephtalate Biodegradability [closed]








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I'm looking into plastics and how they break down. I have learned 3 ways oxo-biodegradation, photodegradation and thermaldegradation. Does anyone know how PET (polyethylene terephtalate) degrades?




It's oxo-biodegradation\* with an asterisk. PET polymers are [polyester](https://en.wikipedia.org/wiki/Polyester) meaning that the monomer units are link by [ester](https://en.wikipedia.org/wiki/Ester) functional groups. This ester group can be [hydrolyzed](https://en.wikipedia.org/wiki/Ester#Hydrolysis_and_saponification) in the presence of water to for the alcohol and acid that formed the ester. For PET the alcohol is [ethylene glycol](https://en.wikipedia.org/wiki/Ethylene_glycol) which is readily digestible by bacteria and the acid is [terephthalic acid](https://en.wikipedia.org/wiki/Terephthalic_acid) which is not as redily digestable but still digestable.


It is for this same reason that [poly(glycolic acid)](https://en.wikipedia.org/wiki/Polyglycolide) which is used in dissolvable stitches and [poly(lactic acid)](https://en.wikipedia.org/wiki/Polylactic_acid) which is used in food containers (and 3D printing) are also biodegradable.


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