Flash Photolysis of Aromatic Diisocyanate-Based Polyurethanes
Polymers and High Performance Materials
The laser flash photolysis of aromatic diisocyanate based polyurethanes in solution provides evidence for a dual mechanism for photodegradation. One of the processes, an N-C bond cleavage, is common to both TDI (toluene diisocyanate) and MDI (methylene 4,4′-diphenyldiisocyanate) based polyurethanes. The second process, exclusive to MDI based polyurethanes, involves formation of a substituted diphenylmethyl radical. The diphenylmethyl radical, which readily reacts with oxygen, is generated either by direct excitation (248 nm) or indirectly by reaction with a tert-butoxy radical produced upon excitation of tert-butyl peroxide at 351 nm.
ACS Symposium Series
Hoyle, C. E.,
No, Y. G.,
Ezzell, K. S.
(1989). Flash Photolysis of Aromatic Diisocyanate-Based Polyurethanes. ACS Symposium Series, 381, 43-56.
Available at: https://aquila.usm.edu/fac_pubs/16113