fredsav - 24-12-2010 at 04:37
Hi guys,
I am seeking the ways to convert a polyester polyol based polyurethane polymer into its monomers. I am aware that i can not obtain the isocyanate
functional groups back, however i am interested in getting the starting materials in any way possible. Any suggestion of hydrolysis or decomposition
of an anionic polyurethane?? Thanks in advance.
Nicodem - 24-12-2010 at 10:05
You can get the corresponding diamine/dianiline by extraction from the basic hydrolysis and further purification, but recovering the corresponding
diol and/or dihydroxycarboxylic acid is not going to be easy since they commonly partitionate better into water and are nonvolatile with steam. I
don't think it is worth the hassle as the price of the diol monomer is generally lower than that of the diamine part (which can be regenerated into
the diisocyanate if so desired).
fredsav - 24-12-2010 at 14:11
how about the route to hydrolysis? shall i just reflux the anionic polyurethane in a strong acid or shall i convert the anionic polymer in to a
nonionic one and reflux in acidic medium.
not_important - 24-12-2010 at 16:40
Reflux in 18-20 percent aqueous HCl, distill off excess HCl until the residue starts getting much solids. Neutralise with NaOH to ph >= 13, steam
distill off the amines, acidify the residue, evaporate until nearly dry, extract with alcohol to get the acids in alcoholic solution.
fredsav - 24-12-2010 at 23:35
ty for the info i will let you know about the result, but have some other work to do these days so it can take some time.