G. A. Razuvaev, B. B. Troitskiǐ, O. S. D'Jachkovskaya
Feb 1, 1974
Citations
0
Influential Citations
2
Citations
Journal
European Polymer Journal
Abstract
Abstract Investigation was made on the effects of mixtures of organic phosphites (tributyl-, trioctyl-, diphenylisooctyl) with isocyanates (triethyl-, tributyl-, triphenyl-, tribenzyltin) upon the rate of dehydrochlorination and crosslinking, and on the absorption spectrum of PVC during degradation in evacuated ampoules at 180°. The effectiveness of stabilizing action of these synergistic mixtures depends on the chemical structures of both phosphite and isocyanate. The activity of isocyanates in mixtures with phosphites decreases in the order: Bz3SnNCO, Ph3SnNCO > Bu3SnNCO > Et3SnNCO. At 180°. triphenyltin isocyanate decomposes with formation of tetraphenyltin and diphenyltin diisocyanate; parallel with disproportionation, decarboxylation of triphenyltin isocyanate occurs, during which carbon dioxide and N,N′-bis(triphenyltin)carbodiimide are generated. N,N′-bis(triphenyltin)carbodiimide is a stabilizer for PVC in thermal degradation and gives synergistic mixtures with organic phosphites.