Right, so if i've got this right, 4,4'-oxydianiline is this (pairs of parens are supposed to be circles denoting benzene rings; apologies for writing out the carbons, i can't do plain hexagons):
C - C C - C
/ \ / \
H2N-C ( ) C-O-C ( ) C-NH2
\ / \ /
C - C C - C
The paraformaldehyde does its job as monomeric formaldehyde (the double quote is a double bond running vertically, horrific i know):
O
"
HO-C-OH
And the polymerisation is a straightforward condensation of the formaldehyde with one of the amines, so the monomer is:
C - C C - C O
/ \ / \ "
...-NH-C ( ) C-O-C ( ) C-NH-C-...
\ / \ /
C - C C - C
And here's a monomer with a bit of its neighbourhood:
- C O C - C C - C O C -
\ " / \ / \ " /
) C-NH-C-NH-C ( ) C-O-C ( ) C-NH-C-NH-C (
/ \ / \ / \
- C C - C C - C C -
There's nothing really radical in terms of the building blocks, but it's a novel combination. Cool.
I had never come across oxydiamine before, but i get the impression it's a common component in polymers, and it looks fairly boring and inert. I guess it's not a single big aromatic system, right? Wrong number of electrons.
The reason this is described as a "hemiaminal" is because the formaldehyde carbon can do keto-enol tautomerism and turn into this:
- C OH C -
\ | /
) C-NH-C-NH-C (
/ | \
- C OH C -
Which has hydroxyl groups and nitrogens on the same carbon, and so is a hemiaminal.
I couldn't figure out the "further cyclize at high temperatures, producing poly(hexahydrotriazine)s", though. Does that mean cyclising using linkages like this? Or is there some way the chains can crosslink?