See towards the bottom of the page, under the section on Moisture-Cured Systems.
http://www.coatings.us.rhodia.com/chemistry.asp (http://www.coatings.us.rhodia.com/chemistry.asp)
or see here:
http://www.psrc.usm.edu/macrog/foamsyn.htm (http://www.psrc.usm.edu/macrog/foamsyn.htm)
> See towards the bottom of the page, under the section on
> Moisture-Cured Systems.
> http://www.coatings.us.rhodia.com/chemistry.asp (http://www.coatings.us.rhodia.com/chemistry.asp)
That is overly simplified. Most one-component systems contain 'capped' isocyanates or amines. Isocyanates are usually derivatised with butanone oxime, amines used as aldimines or ketimines, which hydrolyse with moisture.
isocyanates aren't that moisture sensitive, you certainly don't need anhydrous conditions to work with them. Lots of the polyurethane-based coatings are made in water emulsion (solvent-free laquers), and there is no immediate reaction of the isocyanate with water.
Let's not get into too much detail, polyurethane chemistry is a vast area (during the first 30 or so years no real scientific research was done, there are not many refs, mostly patents from that time, it was mainly trial and error done by the industry)
I'm not fat just horizontally disproportionate.