No abstract

The kinetics of thermal dissociation of urethane, oxazolidone, and isocyanurate groups were measured on model compounds [5-(phenoxymethyl)-3-phenyl-2-oxazolidinone (I), 5-(phenoxymethyl)-3cyclohexyl-2-oxazolidinone (II), l,3,5-triphenyl-s-triazine-2,4,6-(líf,3íf,5H)-trione (III), 1,3,5-tricyclohexyls-triazine-2,4,6-(IH,3H,8H)-trione (IV), and butyl phenylcarbamate] by using and IR-sealed ampule method, developed for these measurements. The kinetics of the initial stage of the thermal decomposition of the model compounds followed first-order kinetics and the kinetic parameters E", A, and TD were determined. It was found that thermal stability of the above-mentioned groups increased in the following order: carbamate < oxazolidone < isocyanurate. The activation energies increased in the same order. Model oxazolidones with the cycloaliphatic substituent on the nitrogen had higher thermal stability than oxazolidones with the aromatic (phenyl) substituent. The cleavage of the oxazolidone rings proceeded through the formation of carbon dioxide and other intermediates which further decomposed, forming aniline, phenol, and various hydrocarbons.

No abstract

The thermal stability of isocyanate-based polymers was investigated as a function of their structure by examining the thermal behavior of model compounds, as well as model polymers.