Ask A Scientist Materials Science Archive

name         Martin
status       other
grade        other
location     N/A

Question -   Why are thermosetting products used? They cannot be 
re-cycled and therefore are not eco-friendly. What advantages do they 
have which make them useable?
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This is more of an economics question then a science question. Certainly, 
thermosets are more difficult to recycle. However, from the producer's 
standpoint, such thermosets are cheap to manufacture and such 
cost-effectiveness is ultimately transferred to the consumer. Until 
consumers are willing to pay a higher price for eco-friendly products (or 
governments legislate it) we will be faced with such materials.

Greg (Roberto Gregorius)
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Thermosetting polymers are essentially one large molecule. This makes them
much more resistant to corrosion, wear, and heat than thermoplastic
polymers of similar composition. That alone does not make them
environmentally bad. It is a tradeoff their greater durability, which
makes what ever they are used to make last longer, or applications where
thermoplastic polymers are not suitable. An example is automobile tires.
Without crosslinked rubber we would not have automobiles, at least as we
know them today.  It is not necessarily true that they cannot be
re-cycled. Tires, for example, can be chopped up and used as "filler" for
asphalt. Other examples of things we take for granted that in many cases
require thermosetting polymers are: electrical insulation and circuit
boards (You would not be reading this e-mail message without thermosetting
polymer components.), particle board used to make desks, counter tops and
the like require a thermosetting "glue" to hold the wood chips together.
Without the thermosetting "glue" there would be no particle board and
there would be millions of tons of wood chips that have very little use
and would otherwise be burned (not very eco-friendly) or dumped in the
garbage
(also not very eco-friendly). In tagging a substance, process, etc.
"unfriendly" it is necessary to look at all facets of the use from cradle to
the grave in assessing how friendly something is. People often focus on one
facet of the problem and come to narrow conclusions which are not correct.

Vince Calder
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