Biuret, thermal stability

Structure 4.1) [7,8,42] as well as absence of unstable biuret and allophanate units [9] seem to be responsible for increased thermal stability and chemical resistance to nonpolar solvents. The reactivity of amine is shown in Scheme 4.2 [42],... 

Of the two reactions, isocyanurate formation is the most widely utilized. Diisocyanates can be converted via this reaction into trifunctional isocyanurate derivatives and subsequently used to introduce branching and crosslinking into a polyurethane.These crosslinks have greater thermal stability than either allophonate or biuret linkages, and hence they are more useful in elevated temperature applications. 

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