Ask A Scientist Chemistry Archive

Question:
What chemical reaction takes place when the two halves of epoxy glue are 
joined together?  And why do some epoxies take longer to cure than others?
 gregoruyyu

Answer:  OK, this may not answer the question, but here goes.
The McGraw-Hill encyclopedia of Science and Technology says
that epoxy resin is a polyether resin formed by the polymerization
of bisphenol A and epichlorohydrin.
 
Past all the 10-dollar words, what that means is that the
two halves of the glue are a resin (composed of relatively
small molecules) and a catalyst (which initiates and speeds up
the reaction).  The reaction that happens involves the
joinging together of smaller molecules, plus reacting them
with oxygen-containing compounds, to form a "polyether resin."
This resin is nice and hard, and very stable.
 
Why some resins require more time to cure, or harden, than
others do, I wasn't able to find out. But I hope
that this helps.  You might try asking this also in the
engineering section...
 
topper