View Full Version : Chemical diagram of spandex joined to spandex
pgood7
Aug 26, 2010, 04:38 AM
I want to have a chemical diagram of spandex joined to spandex so I can see the forces that hold these chemicals together
Unknown008
Aug 26, 2010, 07:52 AM
If you go first to this wikipedia page: Spandex - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Spandex)
Then, following the links to the constituents of the polymer,
Polyurethane - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Polyurethane)
Polyurea - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Polyurea)
You get this:
http://upload.wikimedia.org/wikipedia/commons/c/ca/Polyurethane.png
And this:
http://upload.wikimedia.org/wikipedia/en/0/04/Polyurea.jpg
Those two 'monomer' parts of spandex should help you in finding what are the possible forces which hold spandex together :)
Post what you get! :)
DrBob1
Aug 26, 2010, 11:01 AM
Just to add a little bit to Unknown008's excellent answer.
Spandex is a BLOCK COPOLYMER, that is, it has domains of a "hard" polyurea/polyurethane polymer joined to a "soft" polyester or polyether material. As you can see from the structural formulas, there is a lot of hydrogen bonding in the polyurea portion. The other polymers are flexible, and can stretch under tension.
Thus the Spandex molecules can elongate until the polyester chains are fully extended and then they are stopped by the hard segments. When tension is relaxed entropy takes over and the long, ordered chains recoil and the fabric returns to its original shape.
Spandex is an elastomer, like rubber, but is chemically more stable and longer lasting.
The hydrogen bonds are what hold the molecules together, but by themselves you would have a rock. The soft portions are not associated and, by themselves, would give you soup. But together the two segments give the properties that make the product so successful.