Ask A Scientist Chemistry Archive

name         Hannah S.
status       student
age          10

Question -   How long does it take plastic to decompose?
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Hannah,

Unless the plastic is specially designed to decompose in the soil, such
materials can last a very long time because the chemical bonds that hold
the molecules together are often stronger than nature's power to take
them apart. This means that soil micro-organisms that can easily attack
and decompose things like wood and other formerly living materials
cannot break the various kinds of strong bonds that are common to most
plastics.

Try an experiment: Collect small pieces of a bunch of different kinds of
plastics and a few pieces of different kinds of wood. Bury small samples
of each (a few inches deep) in your yard someplace where they won't be
disturbed. Make a map of what is buried where. If you can remember to do
it, dig them up when you graduate from high school. I think you'll be
surprised at what you learn.

Regards,
ProfHoff 346
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This depends upon the plastic (polymer) and the environment to which it is
exposed. Polystyrene decomposes quickly when exposed to sun and weather, as
do polyvinyl acetates, other polyesters, and polyvinylchloride. On the other
hand, polyvinylfluoride  (DuPont's Teflon (TM)) is virtually indestructable. Even the same
polymer can differ quite widely in its decomposition depending upon how it
is formulated.

Vince Calder
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