Sigmoid pH-rate profile

Even though UF adducts are known to be present in OSB, formaldehyde emissions are not elevated over those expected of an unmodified PF. There are three reasons for this. First, the molar ratio of formaldehyde-to-urea in these situations is very low. It is at least an order of magnitude lower than practical molar ratios for curable UF resin binders. Second, UF adducts are quite stable under the alkaline conditions that prevail in PF-bonded OSB. Finally, the urea only reacts with the formaldehyde that was left behind during polymerization and would have been largely emitted in pressing and cool-down. Urea additions have been shown to reduce PF formaldehyde emissions from hot pressing [121 ].  [c.895]

Chemical kinetics the study of reaction rates in solution (1990) -- [ c.277 ]