No abstract

No abstract

The pyrolysis of a polyurethane obtained from tolylene 2,4‐diisocyanate and ethylene glycol was studied in nitrogen, air, and oxygen from the double aspect of structural change and color formation. The dissociation of the polymer into its components followed by further reactions liberates diisocyanate, the corresponding diamine, and the polypseudourea ether, as well as other degradation products. The color is attributed to the yellowing of TDI, the oxidation of the diamine, and the presence of the polypseudourea ether.

SynopsisThe labile hydrogen of the carbamate group is primarily responsible for color develop ment in the thermal degradation of polyurethane. Replacement of this hydrogen by an alkyl group prevents back-dissociation. Accordingly, a number of N-substituted polyurethanes were prepared, including the methyl, benzyl, bensoyl, acetyl, and the (N'-phenylamido) derivatives. Comparative studies at 150-155OC. showed that the N-methyl and N-bemyl polymers possess outstanding stability under the condition of our testing.

No abstract