Polydicyclopentadiene is made by a nifty reaction called ring-opening metathesis polymerization (ROMP) from
the monomer endo-dicyclopentadiene. Click here if you want to see the monomer in 3-D.
But it's not done yet! There's a double bond left in the bottom ring, as
you can see in the picture of polydicyclopentadiene. These can undergo
vinyl polymerization, to give us a crosslinked thermoset material.
This thermoset is good stuff, but you can't mold a thermoset. So how do
make anything from it? The answer is to make it in chunks that are
already shaped like we want them. The fancy name for this is called
reaction injection molding or RIM for short. Put simply, we fill a
mold full of the monomer, and polymerize it in the mold. That's how we can
make products from thermosets.
Here are some other polymers used as thermosets:
Polymer Science Learning Center
Department of Polymer Science
The University of Southern Mississippi